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[/] [openrisc/] [trunk/] [gnu-src/] [gdb-7.2/] [gdb/] [gdbserver/] [linux-low.c] - Rev 447
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/* Low level interface to ptrace, for the remote server for GDB. Copyright (C) 1995, 1996, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010 Free Software Foundation, Inc. This file is part of GDB. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see <http://www.gnu.org/licenses/>. */ #include "server.h" #include "linux-low.h" #include <sys/wait.h> #include <stdio.h> #include <sys/param.h> #include <sys/ptrace.h> #include <signal.h> #include <sys/ioctl.h> #include <fcntl.h> #include <string.h> #include <stdlib.h> #include <unistd.h> #include <errno.h> #include <sys/syscall.h> #include <sched.h> #include <ctype.h> #include <pwd.h> #include <sys/types.h> #include <dirent.h> #include <sys/stat.h> #include <sys/vfs.h> #include <sys/uio.h> #ifndef ELFMAG0 /* Don't include <linux/elf.h> here. If it got included by gdb_proc_service.h then ELFMAG0 will have been defined. If it didn't get included by gdb_proc_service.h then including it will likely introduce a duplicate definition of elf_fpregset_t. */ #include <elf.h> #endif #ifndef SPUFS_MAGIC #define SPUFS_MAGIC 0x23c9b64e #endif #ifndef PTRACE_GETSIGINFO # define PTRACE_GETSIGINFO 0x4202 # define PTRACE_SETSIGINFO 0x4203 #endif #ifndef O_LARGEFILE #define O_LARGEFILE 0 #endif /* If the system headers did not provide the constants, hard-code the normal values. */ #ifndef PTRACE_EVENT_FORK #define PTRACE_SETOPTIONS 0x4200 #define PTRACE_GETEVENTMSG 0x4201 /* options set using PTRACE_SETOPTIONS */ #define PTRACE_O_TRACESYSGOOD 0x00000001 #define PTRACE_O_TRACEFORK 0x00000002 #define PTRACE_O_TRACEVFORK 0x00000004 #define PTRACE_O_TRACECLONE 0x00000008 #define PTRACE_O_TRACEEXEC 0x00000010 #define PTRACE_O_TRACEVFORKDONE 0x00000020 #define PTRACE_O_TRACEEXIT 0x00000040 /* Wait extended result codes for the above trace options. */ #define PTRACE_EVENT_FORK 1 #define PTRACE_EVENT_VFORK 2 #define PTRACE_EVENT_CLONE 3 #define PTRACE_EVENT_EXEC 4 #define PTRACE_EVENT_VFORK_DONE 5 #define PTRACE_EVENT_EXIT 6 #endif /* PTRACE_EVENT_FORK */ /* We can't always assume that this flag is available, but all systems with the ptrace event handlers also have __WALL, so it's safe to use in some contexts. */ #ifndef __WALL #define __WALL 0x40000000 /* Wait for any child. */ #endif #ifndef W_STOPCODE #define W_STOPCODE(sig) ((sig) << 8 | 0x7f) #endif #ifdef __UCLIBC__ #if !(defined(__UCLIBC_HAS_MMU__) || defined(__ARCH_HAS_MMU__)) #define HAS_NOMMU #endif #endif /* ``all_threads'' is keyed by the LWP ID, which we use as the GDB protocol representation of the thread ID. ``all_lwps'' is keyed by the process ID - which on Linux is (presently) the same as the LWP ID. ``all_processes'' is keyed by the "overall process ID", which GNU/Linux calls tgid, "thread group ID". */ struct inferior_list all_lwps; /* A list of all unknown processes which receive stop signals. Some other process will presumably claim each of these as forked children momentarily. */ struct inferior_list stopped_pids; /* FIXME this is a bit of a hack, and could be removed. */ int stopping_threads; /* FIXME make into a target method? */ int using_threads = 1; /* True if we're presently stabilizing threads (moving them out of jump pads). */ static int stabilizing_threads; /* This flag is true iff we've just created or attached to our first inferior but it has not stopped yet. As soon as it does, we need to call the low target's arch_setup callback. Doing this only on the first inferior avoids reinializing the architecture on every inferior, and avoids messing with the register caches of the already running inferiors. NOTE: this assumes all inferiors under control of gdbserver have the same architecture. */ static int new_inferior; static void linux_resume_one_lwp (struct lwp_info *lwp, int step, int signal, siginfo_t *info); static void linux_resume (struct thread_resume *resume_info, size_t n); static void stop_all_lwps (int suspend, struct lwp_info *except); static void unstop_all_lwps (int unsuspend, struct lwp_info *except); static int linux_wait_for_event (ptid_t ptid, int *wstat, int options); static void *add_lwp (ptid_t ptid); static int linux_stopped_by_watchpoint (void); static void mark_lwp_dead (struct lwp_info *lwp, int wstat); static int linux_core_of_thread (ptid_t ptid); static void proceed_all_lwps (void); static int finish_step_over (struct lwp_info *lwp); static CORE_ADDR get_stop_pc (struct lwp_info *lwp); static int kill_lwp (unsigned long lwpid, int signo); static void linux_enable_event_reporting (int pid); /* True if the low target can hardware single-step. Such targets don't need a BREAKPOINT_REINSERT_ADDR callback. */ static int can_hardware_single_step (void) { return (the_low_target.breakpoint_reinsert_addr == NULL); } /* True if the low target supports memory breakpoints. If so, we'll have a GET_PC implementation. */ static int supports_breakpoints (void) { return (the_low_target.get_pc != NULL); } /* Returns true if this target can support fast tracepoints. This does not mean that the in-process agent has been loaded in the inferior. */ static int supports_fast_tracepoints (void) { return the_low_target.install_fast_tracepoint_jump_pad != NULL; } struct pending_signals { int signal; siginfo_t info; struct pending_signals *prev; }; #define PTRACE_ARG3_TYPE void * #define PTRACE_ARG4_TYPE void * #define PTRACE_XFER_TYPE long #ifdef HAVE_LINUX_REGSETS static char *disabled_regsets; static int num_regsets; #endif /* The read/write ends of the pipe registered as waitable file in the event loop. */ static int linux_event_pipe[2] = { -1, -1 }; /* True if we're currently in async mode. */ #define target_is_async_p() (linux_event_pipe[0] != -1) static void send_sigstop (struct lwp_info *lwp); static void wait_for_sigstop (struct inferior_list_entry *entry); /* Accepts an integer PID; Returns a string representing a file that can be opened to get info for the child process. Space for the result is malloc'd, caller must free. */ char * linux_child_pid_to_exec_file (int pid) { char *name1, *name2; name1 = xmalloc (MAXPATHLEN); name2 = xmalloc (MAXPATHLEN); memset (name2, 0, MAXPATHLEN); sprintf (name1, "/proc/%d/exe", pid); if (readlink (name1, name2, MAXPATHLEN) > 0) { free (name1); return name2; } else { free (name2); return name1; } } /* Return non-zero if HEADER is a 64-bit ELF file. */ static int elf_64_header_p (const Elf64_Ehdr *header) { return (header->e_ident[EI_MAG0] == ELFMAG0 && header->e_ident[EI_MAG1] == ELFMAG1 && header->e_ident[EI_MAG2] == ELFMAG2 && header->e_ident[EI_MAG3] == ELFMAG3 && header->e_ident[EI_CLASS] == ELFCLASS64); } /* Return non-zero if FILE is a 64-bit ELF file, zero if the file is not a 64-bit ELF file, and -1 if the file is not accessible or doesn't exist. */ int elf_64_file_p (const char *file) { Elf64_Ehdr header; int fd; fd = open (file, O_RDONLY); if (fd < 0) return -1; if (read (fd, &header, sizeof (header)) != sizeof (header)) { close (fd); return 0; } close (fd); return elf_64_header_p (&header); } static void delete_lwp (struct lwp_info *lwp) { remove_thread (get_lwp_thread (lwp)); remove_inferior (&all_lwps, &lwp->head); free (lwp->arch_private); free (lwp); } /* Add a process to the common process list, and set its private data. */ static struct process_info * linux_add_process (int pid, int attached) { struct process_info *proc; /* Is this the first process? If so, then set the arch. */ if (all_processes.head == NULL) new_inferior = 1; proc = add_process (pid, attached); proc->private = xcalloc (1, sizeof (*proc->private)); if (the_low_target.new_process != NULL) proc->private->arch_private = the_low_target.new_process (); return proc; } /* Wrapper function for waitpid which handles EINTR, and emulates __WALL for systems where that is not available. */ static int my_waitpid (int pid, int *status, int flags) { int ret, out_errno; if (debug_threads) fprintf (stderr, "my_waitpid (%d, 0x%x)\n", pid, flags); if (flags & __WALL) { sigset_t block_mask, org_mask, wake_mask; int wnohang; wnohang = (flags & WNOHANG) != 0; flags &= ~(__WALL | __WCLONE); flags |= WNOHANG; /* Block all signals while here. This avoids knowing about LinuxThread's signals. */ sigfillset (&block_mask); sigprocmask (SIG_BLOCK, &block_mask, &org_mask); /* ... except during the sigsuspend below. */ sigemptyset (&wake_mask); while (1) { /* Since all signals are blocked, there's no need to check for EINTR here. */ ret = waitpid (pid, status, flags); out_errno = errno; if (ret == -1 && out_errno != ECHILD) break; else if (ret > 0) break; if (flags & __WCLONE) { /* We've tried both flavors now. If WNOHANG is set, there's nothing else to do, just bail out. */ if (wnohang) break; if (debug_threads) fprintf (stderr, "blocking\n"); /* Block waiting for signals. */ sigsuspend (&wake_mask); } flags ^= __WCLONE; } sigprocmask (SIG_SETMASK, &org_mask, NULL); } else { do ret = waitpid (pid, status, flags); while (ret == -1 && errno == EINTR); out_errno = errno; } if (debug_threads) fprintf (stderr, "my_waitpid (%d, 0x%x): status(%x), %d\n", pid, flags, status ? *status : -1, ret); errno = out_errno; return ret; } /* Handle a GNU/Linux extended wait response. If we see a clone event, we need to add the new LWP to our list (and not report the trap to higher layers). */ static void handle_extended_wait (struct lwp_info *event_child, int wstat) { int event = wstat >> 16; struct lwp_info *new_lwp; if (event == PTRACE_EVENT_CLONE) { ptid_t ptid; unsigned long new_pid; int ret, status = W_STOPCODE (SIGSTOP); ptrace (PTRACE_GETEVENTMSG, lwpid_of (event_child), 0, &new_pid); /* If we haven't already seen the new PID stop, wait for it now. */ if (! pull_pid_from_list (&stopped_pids, new_pid)) { /* The new child has a pending SIGSTOP. We can't affect it until it hits the SIGSTOP, but we're already attached. */ ret = my_waitpid (new_pid, &status, __WALL); if (ret == -1) perror_with_name ("waiting for new child"); else if (ret != new_pid) warning ("wait returned unexpected PID %d", ret); else if (!WIFSTOPPED (status)) warning ("wait returned unexpected status 0x%x", status); } linux_enable_event_reporting (new_pid); ptid = ptid_build (pid_of (event_child), new_pid, 0); new_lwp = (struct lwp_info *) add_lwp (ptid); add_thread (ptid, new_lwp); /* Either we're going to immediately resume the new thread or leave it stopped. linux_resume_one_lwp is a nop if it thinks the thread is currently running, so set this first before calling linux_resume_one_lwp. */ new_lwp->stopped = 1; /* Normally we will get the pending SIGSTOP. But in some cases we might get another signal delivered to the group first. If we do get another signal, be sure not to lose it. */ if (WSTOPSIG (status) == SIGSTOP) { if (stopping_threads) new_lwp->stop_pc = get_stop_pc (new_lwp); else linux_resume_one_lwp (new_lwp, 0, 0, NULL); } else { new_lwp->stop_expected = 1; if (stopping_threads) { new_lwp->stop_pc = get_stop_pc (new_lwp); new_lwp->status_pending_p = 1; new_lwp->status_pending = status; } else /* Pass the signal on. This is what GDB does - except shouldn't we really report it instead? */ linux_resume_one_lwp (new_lwp, 0, WSTOPSIG (status), NULL); } /* Always resume the current thread. If we are stopping threads, it will have a pending SIGSTOP; we may as well collect it now. */ linux_resume_one_lwp (event_child, event_child->stepping, 0, NULL); } } /* Return the PC as read from the regcache of LWP, without any adjustment. */ static CORE_ADDR get_pc (struct lwp_info *lwp) { struct thread_info *saved_inferior; struct regcache *regcache; CORE_ADDR pc; if (the_low_target.get_pc == NULL) return 0; saved_inferior = current_inferior; current_inferior = get_lwp_thread (lwp); regcache = get_thread_regcache (current_inferior, 1); pc = (*the_low_target.get_pc) (regcache); if (debug_threads) fprintf (stderr, "pc is 0x%lx\n", (long) pc); current_inferior = saved_inferior; return pc; } /* This function should only be called if LWP got a SIGTRAP. The SIGTRAP could mean several things. On i386, where decr_pc_after_break is non-zero: If we were single-stepping this process using PTRACE_SINGLESTEP, we will get only the one SIGTRAP (even if the instruction we stepped over was a breakpoint). The value of $eip will be the next instruction. If we continue the process using PTRACE_CONT, we will get a SIGTRAP when we hit a breakpoint. The value of $eip will be the instruction after the breakpoint (i.e. needs to be decremented). If we report the SIGTRAP to GDB, we must also report the undecremented PC. If we cancel the SIGTRAP, we must resume at the decremented PC. (Presumably, not yet tested) On a non-decr_pc_after_break machine with hardware or kernel single-step: If we single-step over a breakpoint instruction, our PC will point at the following instruction. If we continue and hit a breakpoint instruction, our PC will point at the breakpoint instruction. */ static CORE_ADDR get_stop_pc (struct lwp_info *lwp) { CORE_ADDR stop_pc; if (the_low_target.get_pc == NULL) return 0; stop_pc = get_pc (lwp); if (WSTOPSIG (lwp->last_status) == SIGTRAP && !lwp->stepping && !lwp->stopped_by_watchpoint && lwp->last_status >> 16 == 0) stop_pc -= the_low_target.decr_pc_after_break; if (debug_threads) fprintf (stderr, "stop pc is 0x%lx\n", (long) stop_pc); return stop_pc; } static void * add_lwp (ptid_t ptid) { struct lwp_info *lwp; lwp = (struct lwp_info *) xmalloc (sizeof (*lwp)); memset (lwp, 0, sizeof (*lwp)); lwp->head.id = ptid; if (the_low_target.new_thread != NULL) lwp->arch_private = the_low_target.new_thread (); add_inferior_to_list (&all_lwps, &lwp->head); return lwp; } /* Start an inferior process and returns its pid. ALLARGS is a vector of program-name and args. */ static int linux_create_inferior (char *program, char **allargs) { struct lwp_info *new_lwp; int pid; ptid_t ptid; #if defined(__UCLIBC__) && defined(HAS_NOMMU) pid = vfork (); #else pid = fork (); #endif if (pid < 0) perror_with_name ("fork"); if (pid == 0) { ptrace (PTRACE_TRACEME, 0, 0, 0); #ifdef __SIGRTMIN /* Bionic doesn't use SIGRTMIN the way glibc does. */ signal (__SIGRTMIN + 1, SIG_DFL); #endif setpgid (0, 0); execv (program, allargs); if (errno == ENOENT) execvp (program, allargs); fprintf (stderr, "Cannot exec %s: %s.\n", program, strerror (errno)); fflush (stderr); _exit (0177); } linux_add_process (pid, 0); ptid = ptid_build (pid, pid, 0); new_lwp = add_lwp (ptid); add_thread (ptid, new_lwp); new_lwp->must_set_ptrace_flags = 1; return pid; } /* Attach to an inferior process. */ static void linux_attach_lwp_1 (unsigned long lwpid, int initial) { ptid_t ptid; struct lwp_info *new_lwp; if (ptrace (PTRACE_ATTACH, lwpid, 0, 0) != 0) { if (!initial) { /* If we fail to attach to an LWP, just warn. */ fprintf (stderr, "Cannot attach to lwp %ld: %s (%d)\n", lwpid, strerror (errno), errno); fflush (stderr); return; } else /* If we fail to attach to a process, report an error. */ error ("Cannot attach to lwp %ld: %s (%d)\n", lwpid, strerror (errno), errno); } if (initial) /* NOTE/FIXME: This lwp might have not been the tgid. */ ptid = ptid_build (lwpid, lwpid, 0); else { /* Note that extracting the pid from the current inferior is safe, since we're always called in the context of the same process as this new thread. */ int pid = pid_of (get_thread_lwp (current_inferior)); ptid = ptid_build (pid, lwpid, 0); } new_lwp = (struct lwp_info *) add_lwp (ptid); add_thread (ptid, new_lwp); /* We need to wait for SIGSTOP before being able to make the next ptrace call on this LWP. */ new_lwp->must_set_ptrace_flags = 1; /* The next time we wait for this LWP we'll see a SIGSTOP as PTRACE_ATTACH brings it to a halt. There are several cases to consider here: 1) gdbserver has already attached to the process and is being notified of a new thread that is being created. In this case we should ignore that SIGSTOP and resume the process. This is handled below by setting stop_expected = 1, and the fact that add_thread sets last_resume_kind == resume_continue. 2) This is the first thread (the process thread), and we're attaching to it via attach_inferior. In this case we want the process thread to stop. This is handled by having linux_attach set last_resume_kind == resume_stop after we return. ??? If the process already has several threads we leave the other threads running. 3) GDB is connecting to gdbserver and is requesting an enumeration of all existing threads. In this case we want the thread to stop. FIXME: This case is currently not properly handled. We should wait for the SIGSTOP but don't. Things work apparently because enough time passes between when we ptrace (ATTACH) and when gdb makes the next ptrace call on the thread. On the other hand, if we are currently trying to stop all threads, we should treat the new thread as if we had sent it a SIGSTOP. This works because we are guaranteed that the add_lwp call above added us to the end of the list, and so the new thread has not yet reached wait_for_sigstop (but will). */ new_lwp->stop_expected = 1; } void linux_attach_lwp (unsigned long lwpid) { linux_attach_lwp_1 (lwpid, 0); } int linux_attach (unsigned long pid) { linux_attach_lwp_1 (pid, 1); linux_add_process (pid, 1); if (!non_stop) { struct thread_info *thread; /* Don't ignore the initial SIGSTOP if we just attached to this process. It will be collected by wait shortly. */ thread = find_thread_ptid (ptid_build (pid, pid, 0)); thread->last_resume_kind = resume_stop; } return 0; } struct counter { int pid; int count; }; static int second_thread_of_pid_p (struct inferior_list_entry *entry, void *args) { struct counter *counter = args; if (ptid_get_pid (entry->id) == counter->pid) { if (++counter->count > 1) return 1; } return 0; } static int last_thread_of_process_p (struct thread_info *thread) { ptid_t ptid = ((struct inferior_list_entry *)thread)->id; int pid = ptid_get_pid (ptid); struct counter counter = { pid , 0 }; return (find_inferior (&all_threads, second_thread_of_pid_p, &counter) == NULL); } /* Kill the inferior lwp. */ static int linux_kill_one_lwp (struct inferior_list_entry *entry, void *args) { struct thread_info *thread = (struct thread_info *) entry; struct lwp_info *lwp = get_thread_lwp (thread); int wstat; int pid = * (int *) args; if (ptid_get_pid (entry->id) != pid) return 0; /* We avoid killing the first thread here, because of a Linux kernel (at least 2.6.0-test7 through 2.6.8-rc4) bug; if we kill the parent before the children get a chance to be reaped, it will remain a zombie forever. */ if (lwpid_of (lwp) == pid) { if (debug_threads) fprintf (stderr, "lkop: is last of process %s\n", target_pid_to_str (entry->id)); return 0; } do { ptrace (PTRACE_KILL, lwpid_of (lwp), 0, 0); /* Make sure it died. The loop is most likely unnecessary. */ pid = linux_wait_for_event (lwp->head.id, &wstat, __WALL); } while (pid > 0 && WIFSTOPPED (wstat)); return 0; } static int linux_kill (int pid) { struct process_info *process; struct lwp_info *lwp; struct thread_info *thread; int wstat; int lwpid; process = find_process_pid (pid); if (process == NULL) return -1; /* If we're killing a running inferior, make sure it is stopped first, as PTRACE_KILL will not work otherwise. */ stop_all_lwps (0, NULL); find_inferior (&all_threads, linux_kill_one_lwp, &pid); /* See the comment in linux_kill_one_lwp. We did not kill the first thread in the list, so do so now. */ lwp = find_lwp_pid (pid_to_ptid (pid)); thread = get_lwp_thread (lwp); if (debug_threads) fprintf (stderr, "lk_1: killing lwp %ld, for pid: %d\n", lwpid_of (lwp), pid); do { ptrace (PTRACE_KILL, lwpid_of (lwp), 0, 0); /* Make sure it died. The loop is most likely unnecessary. */ lwpid = linux_wait_for_event (lwp->head.id, &wstat, __WALL); } while (lwpid > 0 && WIFSTOPPED (wstat)); the_target->mourn (process); /* Since we presently can only stop all lwps of all processes, we need to unstop lwps of other processes. */ unstop_all_lwps (0, NULL); return 0; } static int linux_detach_one_lwp (struct inferior_list_entry *entry, void *args) { struct thread_info *thread = (struct thread_info *) entry; struct lwp_info *lwp = get_thread_lwp (thread); int pid = * (int *) args; if (ptid_get_pid (entry->id) != pid) return 0; /* If this process is stopped but is expecting a SIGSTOP, then make sure we take care of that now. This isn't absolutely guaranteed to collect the SIGSTOP, but is fairly likely to. */ if (lwp->stop_expected) { int wstat; /* Clear stop_expected, so that the SIGSTOP will be reported. */ lwp->stop_expected = 0; linux_resume_one_lwp (lwp, 0, 0, NULL); linux_wait_for_event (lwp->head.id, &wstat, __WALL); } /* Flush any pending changes to the process's registers. */ regcache_invalidate_one ((struct inferior_list_entry *) get_lwp_thread (lwp)); /* Finally, let it resume. */ ptrace (PTRACE_DETACH, lwpid_of (lwp), 0, 0); delete_lwp (lwp); return 0; } static int linux_detach (int pid) { struct process_info *process; process = find_process_pid (pid); if (process == NULL) return -1; /* Stop all threads before detaching. First, ptrace requires that the thread is stopped to sucessfully detach. Second, thread_db may need to uninstall thread event breakpoints from memory, which only works with a stopped process anyway. */ stop_all_lwps (0, NULL); #ifdef USE_THREAD_DB thread_db_detach (process); #endif /* Stabilize threads (move out of jump pads). */ stabilize_threads (); find_inferior (&all_threads, linux_detach_one_lwp, &pid); the_target->mourn (process); /* Since we presently can only stop all lwps of all processes, we need to unstop lwps of other processes. */ unstop_all_lwps (0, NULL); return 0; } /* Remove all LWPs that belong to process PROC from the lwp list. */ static int delete_lwp_callback (struct inferior_list_entry *entry, void *proc) { struct lwp_info *lwp = (struct lwp_info *) entry; struct process_info *process = proc; if (pid_of (lwp) == pid_of (process)) delete_lwp (lwp); return 0; } static void linux_mourn (struct process_info *process) { struct process_info_private *priv; #ifdef USE_THREAD_DB thread_db_mourn (process); #endif find_inferior (&all_lwps, delete_lwp_callback, process); /* Freeing all private data. */ priv = process->private; free (priv->arch_private); free (priv); process->private = NULL; remove_process (process); } static void linux_join (int pid) { int status, ret; struct process_info *process; process = find_process_pid (pid); if (process == NULL) return; do { ret = my_waitpid (pid, &status, 0); if (WIFEXITED (status) || WIFSIGNALED (status)) break; } while (ret != -1 || errno != ECHILD); } /* Return nonzero if the given thread is still alive. */ static int linux_thread_alive (ptid_t ptid) { struct lwp_info *lwp = find_lwp_pid (ptid); /* We assume we always know if a thread exits. If a whole process exited but we still haven't been able to report it to GDB, we'll hold on to the last lwp of the dead process. */ if (lwp != NULL) return !lwp->dead; else return 0; } /* Return 1 if this lwp has an interesting status pending. */ static int status_pending_p_callback (struct inferior_list_entry *entry, void *arg) { struct lwp_info *lwp = (struct lwp_info *) entry; ptid_t ptid = * (ptid_t *) arg; struct thread_info *thread; /* Check if we're only interested in events from a specific process or its lwps. */ if (!ptid_equal (minus_one_ptid, ptid) && ptid_get_pid (ptid) != ptid_get_pid (lwp->head.id)) return 0; thread = get_lwp_thread (lwp); /* If we got a `vCont;t', but we haven't reported a stop yet, do report any status pending the LWP may have. */ if (thread->last_resume_kind == resume_stop && thread->last_status.kind != TARGET_WAITKIND_IGNORE) return 0; return lwp->status_pending_p; } static int same_lwp (struct inferior_list_entry *entry, void *data) { ptid_t ptid = *(ptid_t *) data; int lwp; if (ptid_get_lwp (ptid) != 0) lwp = ptid_get_lwp (ptid); else lwp = ptid_get_pid (ptid); if (ptid_get_lwp (entry->id) == lwp) return 1; return 0; } struct lwp_info * find_lwp_pid (ptid_t ptid) { return (struct lwp_info*) find_inferior (&all_lwps, same_lwp, &ptid); } static struct lwp_info * linux_wait_for_lwp (ptid_t ptid, int *wstatp, int options) { int ret; int to_wait_for = -1; struct lwp_info *child = NULL; if (debug_threads) fprintf (stderr, "linux_wait_for_lwp: %s\n", target_pid_to_str (ptid)); if (ptid_equal (ptid, minus_one_ptid)) to_wait_for = -1; /* any child */ else to_wait_for = ptid_get_lwp (ptid); /* this lwp only */ options |= __WALL; retry: ret = my_waitpid (to_wait_for, wstatp, options); if (ret == 0 || (ret == -1 && errno == ECHILD && (options & WNOHANG))) return NULL; else if (ret == -1) perror_with_name ("waitpid"); if (debug_threads && (!WIFSTOPPED (*wstatp) || (WSTOPSIG (*wstatp) != 32 && WSTOPSIG (*wstatp) != 33))) fprintf (stderr, "Got an event from %d (%x)\n", ret, *wstatp); child = find_lwp_pid (pid_to_ptid (ret)); /* If we didn't find a process, one of two things presumably happened: - A process we started and then detached from has exited. Ignore it. - A process we are controlling has forked and the new child's stop was reported to us by the kernel. Save its PID. */ if (child == NULL && WIFSTOPPED (*wstatp)) { add_pid_to_list (&stopped_pids, ret); goto retry; } else if (child == NULL) goto retry; child->stopped = 1; child->last_status = *wstatp; /* Architecture-specific setup after inferior is running. This needs to happen after we have attached to the inferior and it is stopped for the first time, but before we access any inferior registers. */ if (new_inferior) { the_low_target.arch_setup (); #ifdef HAVE_LINUX_REGSETS memset (disabled_regsets, 0, num_regsets); #endif new_inferior = 0; } /* Fetch the possibly triggered data watchpoint info and store it in CHILD. On some archs, like x86, that use debug registers to set watchpoints, it's possible that the way to know which watched address trapped, is to check the register that is used to select which address to watch. Problem is, between setting the watchpoint and reading back which data address trapped, the user may change the set of watchpoints, and, as a consequence, GDB changes the debug registers in the inferior. To avoid reading back a stale stopped-data-address when that happens, we cache in LP the fact that a watchpoint trapped, and the corresponding data address, as soon as we see CHILD stop with a SIGTRAP. If GDB changes the debug registers meanwhile, we have the cached data we can rely on. */ if (WIFSTOPPED (*wstatp) && WSTOPSIG (*wstatp) == SIGTRAP) { if (the_low_target.stopped_by_watchpoint == NULL) { child->stopped_by_watchpoint = 0; } else { struct thread_info *saved_inferior; saved_inferior = current_inferior; current_inferior = get_lwp_thread (child); child->stopped_by_watchpoint = the_low_target.stopped_by_watchpoint (); if (child->stopped_by_watchpoint) { if (the_low_target.stopped_data_address != NULL) child->stopped_data_address = the_low_target.stopped_data_address (); else child->stopped_data_address = 0; } current_inferior = saved_inferior; } } /* Store the STOP_PC, with adjustment applied. This depends on the architecture being defined already (so that CHILD has a valid regcache), and on LAST_STATUS being set (to check for SIGTRAP or not). */ if (WIFSTOPPED (*wstatp)) child->stop_pc = get_stop_pc (child); if (debug_threads && WIFSTOPPED (*wstatp) && the_low_target.get_pc != NULL) { struct thread_info *saved_inferior = current_inferior; struct regcache *regcache; CORE_ADDR pc; current_inferior = get_lwp_thread (child); regcache = get_thread_regcache (current_inferior, 1); pc = (*the_low_target.get_pc) (regcache); fprintf (stderr, "linux_wait_for_lwp: pc is 0x%lx\n", (long) pc); current_inferior = saved_inferior; } return child; } /* This function should only be called if the LWP got a SIGTRAP. Handle any tracepoint steps or hits. Return true if a tracepoint event was handled, 0 otherwise. */ static int handle_tracepoints (struct lwp_info *lwp) { struct thread_info *tinfo = get_lwp_thread (lwp); int tpoint_related_event = 0; /* If this tracepoint hit causes a tracing stop, we'll immediately uninsert tracepoints. To do this, we temporarily pause all threads, unpatch away, and then unpause threads. We need to make sure the unpausing doesn't resume LWP too. */ lwp->suspended++; /* And we need to be sure that any all-threads-stopping doesn't try to move threads out of the jump pads, as it could deadlock the inferior (LWP could be in the jump pad, maybe even holding the lock.) */ /* Do any necessary step collect actions. */ tpoint_related_event |= tracepoint_finished_step (tinfo, lwp->stop_pc); tpoint_related_event |= handle_tracepoint_bkpts (tinfo, lwp->stop_pc); /* See if we just hit a tracepoint and do its main collect actions. */ tpoint_related_event |= tracepoint_was_hit (tinfo, lwp->stop_pc); lwp->suspended--; gdb_assert (lwp->suspended == 0); gdb_assert (!stabilizing_threads || lwp->collecting_fast_tracepoint); if (tpoint_related_event) { if (debug_threads) fprintf (stderr, "got a tracepoint event\n"); return 1; } return 0; } /* Convenience wrapper. Returns true if LWP is presently collecting a fast tracepoint. */ static int linux_fast_tracepoint_collecting (struct lwp_info *lwp, struct fast_tpoint_collect_status *status) { CORE_ADDR thread_area; if (the_low_target.get_thread_area == NULL) return 0; /* Get the thread area address. This is used to recognize which thread is which when tracing with the in-process agent library. We don't read anything from the address, and treat it as opaque; it's the address itself that we assume is unique per-thread. */ if ((*the_low_target.get_thread_area) (lwpid_of (lwp), &thread_area) == -1) return 0; return fast_tracepoint_collecting (thread_area, lwp->stop_pc, status); } /* The reason we resume in the caller, is because we want to be able to pass lwp->status_pending as WSTAT, and we need to clear status_pending_p before resuming, otherwise, linux_resume_one_lwp refuses to resume. */ static int maybe_move_out_of_jump_pad (struct lwp_info *lwp, int *wstat) { struct thread_info *saved_inferior; saved_inferior = current_inferior; current_inferior = get_lwp_thread (lwp); if ((wstat == NULL || (WIFSTOPPED (*wstat) && WSTOPSIG (*wstat) != SIGTRAP)) && supports_fast_tracepoints () && in_process_agent_loaded ()) { struct fast_tpoint_collect_status status; int r; if (debug_threads) fprintf (stderr, "\ Checking whether LWP %ld needs to move out of the jump pad.\n", lwpid_of (lwp)); r = linux_fast_tracepoint_collecting (lwp, &status); if (wstat == NULL || (WSTOPSIG (*wstat) != SIGILL && WSTOPSIG (*wstat) != SIGFPE && WSTOPSIG (*wstat) != SIGSEGV && WSTOPSIG (*wstat) != SIGBUS)) { lwp->collecting_fast_tracepoint = r; if (r != 0) { if (r == 1 && lwp->exit_jump_pad_bkpt == NULL) { /* Haven't executed the original instruction yet. Set breakpoint there, and wait till it's hit, then single-step until exiting the jump pad. */ lwp->exit_jump_pad_bkpt = set_breakpoint_at (status.adjusted_insn_addr, NULL); } if (debug_threads) fprintf (stderr, "\ Checking whether LWP %ld needs to move out of the jump pad...it does\n", lwpid_of (lwp)); return 1; } } else { /* If we get a synchronous signal while collecting, *and* while executing the (relocated) original instruction, reset the PC to point at the tpoint address, before reporting to GDB. Otherwise, it's an IPA lib bug: just report the signal to GDB, and pray for the best. */ lwp->collecting_fast_tracepoint = 0; if (r != 0 && (status.adjusted_insn_addr <= lwp->stop_pc && lwp->stop_pc < status.adjusted_insn_addr_end)) { siginfo_t info; struct regcache *regcache; /* The si_addr on a few signals references the address of the faulting instruction. Adjust that as well. */ if ((WSTOPSIG (*wstat) == SIGILL || WSTOPSIG (*wstat) == SIGFPE || WSTOPSIG (*wstat) == SIGBUS || WSTOPSIG (*wstat) == SIGSEGV) && ptrace (PTRACE_GETSIGINFO, lwpid_of (lwp), 0, &info) == 0 /* Final check just to make sure we don't clobber the siginfo of non-kernel-sent signals. */ && (uintptr_t) info.si_addr == lwp->stop_pc) { info.si_addr = (void *) (uintptr_t) status.tpoint_addr; ptrace (PTRACE_SETSIGINFO, lwpid_of (lwp), 0, &info); } regcache = get_thread_regcache (get_lwp_thread (lwp), 1); (*the_low_target.set_pc) (regcache, status.tpoint_addr); lwp->stop_pc = status.tpoint_addr; /* Cancel any fast tracepoint lock this thread was holding. */ force_unlock_trace_buffer (); } if (lwp->exit_jump_pad_bkpt != NULL) { if (debug_threads) fprintf (stderr, "Cancelling fast exit-jump-pad: removing bkpt. " "stopping all threads momentarily.\n"); stop_all_lwps (1, lwp); cancel_breakpoints (); delete_breakpoint (lwp->exit_jump_pad_bkpt); lwp->exit_jump_pad_bkpt = NULL; unstop_all_lwps (1, lwp); gdb_assert (lwp->suspended >= 0); } } } if (debug_threads) fprintf (stderr, "\ Checking whether LWP %ld needs to move out of the jump pad...no\n", lwpid_of (lwp)); return 0; } /* Enqueue one signal in the "signals to report later when out of the jump pad" list. */ static void enqueue_one_deferred_signal (struct lwp_info *lwp, int *wstat) { struct pending_signals *p_sig; if (debug_threads) fprintf (stderr, "\ Deferring signal %d for LWP %ld.\n", WSTOPSIG (*wstat), lwpid_of (lwp)); if (debug_threads) { struct pending_signals *sig; for (sig = lwp->pending_signals_to_report; sig != NULL; sig = sig->prev) fprintf (stderr, " Already queued %d\n", sig->signal); fprintf (stderr, " (no more currently queued signals)\n"); } p_sig = xmalloc (sizeof (*p_sig)); p_sig->prev = lwp->pending_signals_to_report; p_sig->signal = WSTOPSIG (*wstat); memset (&p_sig->info, 0, sizeof (siginfo_t)); ptrace (PTRACE_GETSIGINFO, lwpid_of (lwp), 0, &p_sig->info); lwp->pending_signals_to_report = p_sig; } /* Dequeue one signal from the "signals to report later when out of the jump pad" list. */ static int dequeue_one_deferred_signal (struct lwp_info *lwp, int *wstat) { if (lwp->pending_signals_to_report != NULL) { struct pending_signals **p_sig; p_sig = &lwp->pending_signals_to_report; while ((*p_sig)->prev != NULL) p_sig = &(*p_sig)->prev; *wstat = W_STOPCODE ((*p_sig)->signal); if ((*p_sig)->info.si_signo != 0) ptrace (PTRACE_SETSIGINFO, lwpid_of (lwp), 0, &(*p_sig)->info); free (*p_sig); *p_sig = NULL; if (debug_threads) fprintf (stderr, "Reporting deferred signal %d for LWP %ld.\n", WSTOPSIG (*wstat), lwpid_of (lwp)); if (debug_threads) { struct pending_signals *sig; for (sig = lwp->pending_signals_to_report; sig != NULL; sig = sig->prev) fprintf (stderr, " Still queued %d\n", sig->signal); fprintf (stderr, " (no more queued signals)\n"); } return 1; } return 0; } /* Arrange for a breakpoint to be hit again later. We don't keep the SIGTRAP status and don't forward the SIGTRAP signal to the LWP. We will handle the current event, eventually we will resume this LWP, and this breakpoint will trap again. */ static int cancel_breakpoint (struct lwp_info *lwp) { struct thread_info *saved_inferior; /* There's nothing to do if we don't support breakpoints. */ if (!supports_breakpoints ()) return 0; /* breakpoint_at reads from current inferior. */ saved_inferior = current_inferior; current_inferior = get_lwp_thread (lwp); if ((*the_low_target.breakpoint_at) (lwp->stop_pc)) { if (debug_threads) fprintf (stderr, "CB: Push back breakpoint for %s\n", target_pid_to_str (ptid_of (lwp))); /* Back up the PC if necessary. */ if (the_low_target.decr_pc_after_break) { struct regcache *regcache = get_thread_regcache (current_inferior, 1); (*the_low_target.set_pc) (regcache, lwp->stop_pc); } current_inferior = saved_inferior; return 1; } else { if (debug_threads) fprintf (stderr, "CB: No breakpoint found at %s for [%s]\n", paddress (lwp->stop_pc), target_pid_to_str (ptid_of (lwp))); } current_inferior = saved_inferior; return 0; } /* When the event-loop is doing a step-over, this points at the thread being stepped. */ ptid_t step_over_bkpt; /* Wait for an event from child PID. If PID is -1, wait for any child. Store the stop status through the status pointer WSTAT. OPTIONS is passed to the waitpid call. Return 0 if no child stop event was found and OPTIONS contains WNOHANG. Return the PID of the stopped child otherwise. */ static int linux_wait_for_event_1 (ptid_t ptid, int *wstat, int options) { struct lwp_info *event_child, *requested_child; event_child = NULL; requested_child = NULL; /* Check for a lwp with a pending status. */ if (ptid_equal (ptid, minus_one_ptid) || ptid_equal (pid_to_ptid (ptid_get_pid (ptid)), ptid)) { event_child = (struct lwp_info *) find_inferior (&all_lwps, status_pending_p_callback, &ptid); if (debug_threads && event_child) fprintf (stderr, "Got a pending child %ld\n", lwpid_of (event_child)); } else { requested_child = find_lwp_pid (ptid); if (!stopping_threads && requested_child->status_pending_p && requested_child->collecting_fast_tracepoint) { enqueue_one_deferred_signal (requested_child, &requested_child->status_pending); requested_child->status_pending_p = 0; requested_child->status_pending = 0; linux_resume_one_lwp (requested_child, 0, 0, NULL); } if (requested_child->suspended && requested_child->status_pending_p) fatal ("requesting an event out of a suspended child?"); if (requested_child->status_pending_p) event_child = requested_child; } if (event_child != NULL) { if (debug_threads) fprintf (stderr, "Got an event from pending child %ld (%04x)\n", lwpid_of (event_child), event_child->status_pending); *wstat = event_child->status_pending; event_child->status_pending_p = 0; event_child->status_pending = 0; current_inferior = get_lwp_thread (event_child); return lwpid_of (event_child); } /* We only enter this loop if no process has a pending wait status. Thus any action taken in response to a wait status inside this loop is responding as soon as we detect the status, not after any pending events. */ while (1) { event_child = linux_wait_for_lwp (ptid, wstat, options); if ((options & WNOHANG) && event_child == NULL) { if (debug_threads) fprintf (stderr, "WNOHANG set, no event found\n"); return 0; } if (event_child == NULL) error ("event from unknown child"); current_inferior = get_lwp_thread (event_child); /* Check for thread exit. */ if (! WIFSTOPPED (*wstat)) { if (debug_threads) fprintf (stderr, "LWP %ld exiting\n", lwpid_of (event_child)); /* If the last thread is exiting, just return. */ if (last_thread_of_process_p (current_inferior)) { if (debug_threads) fprintf (stderr, "LWP %ld is last lwp of process\n", lwpid_of (event_child)); return lwpid_of (event_child); } if (!non_stop) { current_inferior = (struct thread_info *) all_threads.head; if (debug_threads) fprintf (stderr, "Current inferior is now %ld\n", lwpid_of (get_thread_lwp (current_inferior))); } else { current_inferior = NULL; if (debug_threads) fprintf (stderr, "Current inferior is now <NULL>\n"); } /* If we were waiting for this particular child to do something... well, it did something. */ if (requested_child != NULL) { int lwpid = lwpid_of (event_child); /* Cancel the step-over operation --- the thread that started it is gone. */ if (finish_step_over (event_child)) unstop_all_lwps (1, event_child); delete_lwp (event_child); return lwpid; } delete_lwp (event_child); /* Wait for a more interesting event. */ continue; } if (event_child->must_set_ptrace_flags) { linux_enable_event_reporting (lwpid_of (event_child)); event_child->must_set_ptrace_flags = 0; } if (WIFSTOPPED (*wstat) && WSTOPSIG (*wstat) == SIGTRAP && *wstat >> 16 != 0) { handle_extended_wait (event_child, *wstat); continue; } if (WIFSTOPPED (*wstat) && WSTOPSIG (*wstat) == SIGSTOP && event_child->stop_expected) { int should_stop; if (debug_threads) fprintf (stderr, "Expected stop.\n"); event_child->stop_expected = 0; should_stop = (current_inferior->last_resume_kind == resume_stop || stopping_threads); if (!should_stop) { linux_resume_one_lwp (event_child, event_child->stepping, 0, NULL); continue; } } return lwpid_of (event_child); } /* NOTREACHED */ return 0; } static int linux_wait_for_event (ptid_t ptid, int *wstat, int options) { ptid_t wait_ptid; if (ptid_is_pid (ptid)) { /* A request to wait for a specific tgid. This is not possible with waitpid, so instead, we wait for any child, and leave children we're not interested in right now with a pending status to report later. */ wait_ptid = minus_one_ptid; } else wait_ptid = ptid; while (1) { int event_pid; event_pid = linux_wait_for_event_1 (wait_ptid, wstat, options); if (event_pid > 0 && ptid_is_pid (ptid) && ptid_get_pid (ptid) != event_pid) { struct lwp_info *event_child = find_lwp_pid (pid_to_ptid (event_pid)); if (! WIFSTOPPED (*wstat)) mark_lwp_dead (event_child, *wstat); else { event_child->status_pending_p = 1; event_child->status_pending = *wstat; } } else return event_pid; } } /* Count the LWP's that have had events. */ static int count_events_callback (struct inferior_list_entry *entry, void *data) { struct lwp_info *lp = (struct lwp_info *) entry; struct thread_info *thread = get_lwp_thread (lp); int *count = data; gdb_assert (count != NULL); /* Count only resumed LWPs that have a SIGTRAP event pending that should be reported to GDB. */ if (thread->last_status.kind == TARGET_WAITKIND_IGNORE && thread->last_resume_kind != resume_stop && lp->status_pending_p && WIFSTOPPED (lp->status_pending) && WSTOPSIG (lp->status_pending) == SIGTRAP && !breakpoint_inserted_here (lp->stop_pc)) (*count)++; return 0; } /* Select the LWP (if any) that is currently being single-stepped. */ static int select_singlestep_lwp_callback (struct inferior_list_entry *entry, void *data) { struct lwp_info *lp = (struct lwp_info *) entry; struct thread_info *thread = get_lwp_thread (lp); if (thread->last_status.kind == TARGET_WAITKIND_IGNORE && thread->last_resume_kind == resume_step && lp->status_pending_p) return 1; else return 0; } /* Select the Nth LWP that has had a SIGTRAP event that should be reported to GDB. */ static int select_event_lwp_callback (struct inferior_list_entry *entry, void *data) { struct lwp_info *lp = (struct lwp_info *) entry; struct thread_info *thread = get_lwp_thread (lp); int *selector = data; gdb_assert (selector != NULL); /* Select only resumed LWPs that have a SIGTRAP event pending. */ if (thread->last_resume_kind != resume_stop && thread->last_status.kind == TARGET_WAITKIND_IGNORE && lp->status_pending_p && WIFSTOPPED (lp->status_pending) && WSTOPSIG (lp->status_pending) == SIGTRAP && !breakpoint_inserted_here (lp->stop_pc)) if ((*selector)-- == 0) return 1; return 0; } static int cancel_breakpoints_callback (struct inferior_list_entry *entry, void *data) { struct lwp_info *lp = (struct lwp_info *) entry; struct thread_info *thread = get_lwp_thread (lp); struct lwp_info *event_lp = data; /* Leave the LWP that has been elected to receive a SIGTRAP alone. */ if (lp == event_lp) return 0; /* If a LWP other than the LWP that we're reporting an event for has hit a GDB breakpoint (as opposed to some random trap signal), then just arrange for it to hit it again later. We don't keep the SIGTRAP status and don't forward the SIGTRAP signal to the LWP. We will handle the current event, eventually we will resume all LWPs, and this one will get its breakpoint trap again. If we do not do this, then we run the risk that the user will delete or disable the breakpoint, but the LWP will have already tripped on it. */ if (thread->last_resume_kind != resume_stop && thread->last_status.kind == TARGET_WAITKIND_IGNORE && lp->status_pending_p && WIFSTOPPED (lp->status_pending) && WSTOPSIG (lp->status_pending) == SIGTRAP && !lp->stepping && !lp->stopped_by_watchpoint && cancel_breakpoint (lp)) /* Throw away the SIGTRAP. */ lp->status_pending_p = 0; return 0; } static void linux_cancel_breakpoints (void) { find_inferior (&all_lwps, cancel_breakpoints_callback, NULL); } /* Select one LWP out of those that have events pending. */ static void select_event_lwp (struct lwp_info **orig_lp) { int num_events = 0; int random_selector; struct lwp_info *event_lp; /* Give preference to any LWP that is being single-stepped. */ event_lp = (struct lwp_info *) find_inferior (&all_lwps, select_singlestep_lwp_callback, NULL); if (event_lp != NULL) { if (debug_threads) fprintf (stderr, "SEL: Select single-step %s\n", target_pid_to_str (ptid_of (event_lp))); } else { /* No single-stepping LWP. Select one at random, out of those which have had SIGTRAP events. */ /* First see how many SIGTRAP events we have. */ find_inferior (&all_lwps, count_events_callback, &num_events); /* Now randomly pick a LWP out of those that have had a SIGTRAP. */ random_selector = (int) ((num_events * (double) rand ()) / (RAND_MAX + 1.0)); if (debug_threads && num_events > 1) fprintf (stderr, "SEL: Found %d SIGTRAP events, selecting #%d\n", num_events, random_selector); event_lp = (struct lwp_info *) find_inferior (&all_lwps, select_event_lwp_callback, &random_selector); } if (event_lp != NULL) { /* Switch the event LWP. */ *orig_lp = event_lp; } } /* Set this inferior LWP's state as "want-stopped". We won't resume this LWP until the client gives us another action for it. */ static void gdb_wants_lwp_stopped (struct inferior_list_entry *entry) { struct lwp_info *lwp = (struct lwp_info *) entry; struct thread_info *thread = get_lwp_thread (lwp); /* Most threads are stopped implicitly (all-stop); tag that with signal 0. The thread being explicitly reported stopped to the client, gets it's status fixed up afterwards. */ thread->last_status.kind = TARGET_WAITKIND_STOPPED; thread->last_status.value.sig = TARGET_SIGNAL_0; thread->last_resume_kind = resume_stop; } /* Decrement the suspend count of an LWP. */ static int unsuspend_one_lwp (struct inferior_list_entry *entry, void *except) { struct lwp_info *lwp = (struct lwp_info *) entry; /* Ignore EXCEPT. */ if (lwp == except) return 0; lwp->suspended--; gdb_assert (lwp->suspended >= 0); return 0; } /* Decrement the suspend count of all LWPs, except EXCEPT, if non NULL. */ static void unsuspend_all_lwps (struct lwp_info *except) { find_inferior (&all_lwps, unsuspend_one_lwp, except); } /* Set all LWP's states as "want-stopped". */ static void gdb_wants_all_stopped (void) { for_each_inferior (&all_lwps, gdb_wants_lwp_stopped); } static void move_out_of_jump_pad_callback (struct inferior_list_entry *entry); static int stuck_in_jump_pad_callback (struct inferior_list_entry *entry, void *data); static int lwp_running (struct inferior_list_entry *entry, void *data); static ptid_t linux_wait_1 (ptid_t ptid, struct target_waitstatus *ourstatus, int target_options); /* Stabilize threads (move out of jump pads). If a thread is midway collecting a fast tracepoint, we need to finish the collection and move it out of the jump pad before reporting the signal. This avoids recursion while collecting (when a signal arrives midway, and the signal handler itself collects), which would trash the trace buffer. In case the user set a breakpoint in a signal handler, this avoids the backtrace showing the jump pad, etc.. Most importantly, there are certain things we can't do safely if threads are stopped in a jump pad (or in its callee's). For example: - starting a new trace run. A thread still collecting the previous run, could trash the trace buffer when resumed. The trace buffer control structures would have been reset but the thread had no way to tell. The thread could even midway memcpy'ing to the buffer, which would mean that when resumed, it would clobber the trace buffer that had been set for a new run. - we can't rewrite/reuse the jump pads for new tracepoints safely. Say you do tstart while a thread is stopped midway while collecting. When the thread is later resumed, it finishes the collection, and returns to the jump pad, to execute the original instruction that was under the tracepoint jump at the time the older run had been started. If the jump pad had been rewritten since for something else in the new run, the thread would now execute the wrong / random instructions. */ static void linux_stabilize_threads (void) { struct thread_info *save_inferior; struct lwp_info *lwp_stuck; lwp_stuck = (struct lwp_info *) find_inferior (&all_lwps, stuck_in_jump_pad_callback, NULL); if (lwp_stuck != NULL) { fprintf (stderr, "can't stabilize, LWP %ld is stuck in jump pad\n", lwpid_of (lwp_stuck)); return; } save_inferior = current_inferior; stabilizing_threads = 1; /* Kick 'em all. */ for_each_inferior (&all_lwps, move_out_of_jump_pad_callback); /* Loop until all are stopped out of the jump pads. */ while (find_inferior (&all_lwps, lwp_running, NULL) != NULL) { struct target_waitstatus ourstatus; struct lwp_info *lwp; ptid_t ptid; int wstat; /* Note that we go through the full wait even loop. While moving threads out of jump pad, we need to be able to step over internal breakpoints and such. */ ptid = linux_wait_1 (minus_one_ptid, &ourstatus, 0); if (ourstatus.kind == TARGET_WAITKIND_STOPPED) { lwp = get_thread_lwp (current_inferior); /* Lock it. */ lwp->suspended++; if (ourstatus.value.sig != TARGET_SIGNAL_0 || current_inferior->last_resume_kind == resume_stop) { wstat = W_STOPCODE (target_signal_to_host (ourstatus.value.sig)); enqueue_one_deferred_signal (lwp, &wstat); } } } find_inferior (&all_lwps, unsuspend_one_lwp, NULL); stabilizing_threads = 0; current_inferior = save_inferior; lwp_stuck = (struct lwp_info *) find_inferior (&all_lwps, stuck_in_jump_pad_callback, NULL); if (lwp_stuck != NULL) { if (debug_threads) fprintf (stderr, "couldn't stabilize, LWP %ld got stuck in jump pad\n", lwpid_of (lwp_stuck)); } } /* Wait for process, returns status. */ static ptid_t linux_wait_1 (ptid_t ptid, struct target_waitstatus *ourstatus, int target_options) { int w; struct lwp_info *event_child; int options; int pid; int step_over_finished; int bp_explains_trap; int maybe_internal_trap; int report_to_gdb; int trace_event; /* Translate generic target options into linux options. */ options = __WALL; if (target_options & TARGET_WNOHANG) options |= WNOHANG; retry: bp_explains_trap = 0; trace_event = 0; ourstatus->kind = TARGET_WAITKIND_IGNORE; /* If we were only supposed to resume one thread, only wait for that thread - if it's still alive. If it died, however - which can happen if we're coming from the thread death case below - then we need to make sure we restart the other threads. We could pick a thread at random or restart all; restarting all is less arbitrary. */ if (!non_stop && !ptid_equal (cont_thread, null_ptid) && !ptid_equal (cont_thread, minus_one_ptid)) { struct thread_info *thread; thread = (struct thread_info *) find_inferior_id (&all_threads, cont_thread); /* No stepping, no signal - unless one is pending already, of course. */ if (thread == NULL) { struct thread_resume resume_info; resume_info.thread = minus_one_ptid; resume_info.kind = resume_continue; resume_info.sig = 0; linux_resume (&resume_info, 1); } else ptid = cont_thread; } if (ptid_equal (step_over_bkpt, null_ptid)) pid = linux_wait_for_event (ptid, &w, options); else { if (debug_threads) fprintf (stderr, "step_over_bkpt set [%s], doing a blocking wait\n", target_pid_to_str (step_over_bkpt)); pid = linux_wait_for_event (step_over_bkpt, &w, options & ~WNOHANG); } if (pid == 0) /* only if TARGET_WNOHANG */ return null_ptid; event_child = get_thread_lwp (current_inferior); /* If we are waiting for a particular child, and it exited, linux_wait_for_event will return its exit status. Similarly if the last child exited. If this is not the last child, however, do not report it as exited until there is a 'thread exited' response available in the remote protocol. Instead, just wait for another event. This should be safe, because if the thread crashed we will already have reported the termination signal to GDB; that should stop any in-progress stepping operations, etc. Report the exit status of the last thread to exit. This matches LinuxThreads' behavior. */ if (last_thread_of_process_p (current_inferior)) { if (WIFEXITED (w) || WIFSIGNALED (w)) { if (WIFEXITED (w)) { ourstatus->kind = TARGET_WAITKIND_EXITED; ourstatus->value.integer = WEXITSTATUS (w); if (debug_threads) fprintf (stderr, "\nChild exited with retcode = %x \n", WEXITSTATUS (w)); } else { ourstatus->kind = TARGET_WAITKIND_SIGNALLED; ourstatus->value.sig = target_signal_from_host (WTERMSIG (w)); if (debug_threads) fprintf (stderr, "\nChild terminated with signal = %x \n", WTERMSIG (w)); } return ptid_of (event_child); } } else { if (!WIFSTOPPED (w)) goto retry; } /* If this event was not handled before, and is not a SIGTRAP, we report it. SIGILL and SIGSEGV are also treated as traps in case a breakpoint is inserted at the current PC. If this target does not support internal breakpoints at all, we also report the SIGTRAP without further processing; it's of no concern to us. */ maybe_internal_trap = (supports_breakpoints () && (WSTOPSIG (w) == SIGTRAP || ((WSTOPSIG (w) == SIGILL || WSTOPSIG (w) == SIGSEGV) && (*the_low_target.breakpoint_at) (event_child->stop_pc)))); if (maybe_internal_trap) { /* Handle anything that requires bookkeeping before deciding to report the event or continue waiting. */ /* First check if we can explain the SIGTRAP with an internal breakpoint, or if we should possibly report the event to GDB. Do this before anything that may remove or insert a breakpoint. */ bp_explains_trap = breakpoint_inserted_here (event_child->stop_pc); /* We have a SIGTRAP, possibly a step-over dance has just finished. If so, tweak the state machine accordingly, reinsert breakpoints and delete any reinsert (software single-step) breakpoints. */ step_over_finished = finish_step_over (event_child); /* Now invoke the callbacks of any internal breakpoints there. */ check_breakpoints (event_child->stop_pc); /* Handle tracepoint data collecting. This may overflow the trace buffer, and cause a tracing stop, removing breakpoints. */ trace_event = handle_tracepoints (event_child); if (bp_explains_trap) { /* If we stepped or ran into an internal breakpoint, we've already handled it. So next time we resume (from this PC), we should step over it. */ if (debug_threads) fprintf (stderr, "Hit a gdbserver breakpoint.\n"); if (breakpoint_here (event_child->stop_pc)) event_child->need_step_over = 1; } } else { /* We have some other signal, possibly a step-over dance was in progress, and it should be cancelled too. */ step_over_finished = finish_step_over (event_child); } /* We have all the data we need. Either report the event to GDB, or resume threads and keep waiting for more. */ /* If we're collecting a fast tracepoint, finish the collection and move out of the jump pad before delivering a signal. See linux_stabilize_threads. */ if (WIFSTOPPED (w) && WSTOPSIG (w) != SIGTRAP && supports_fast_tracepoints () && in_process_agent_loaded ()) { if (debug_threads) fprintf (stderr, "Got signal %d for LWP %ld. Check if we need " "to defer or adjust it.\n", WSTOPSIG (w), lwpid_of (event_child)); /* Allow debugging the jump pad itself. */ if (current_inferior->last_resume_kind != resume_step && maybe_move_out_of_jump_pad (event_child, &w)) { enqueue_one_deferred_signal (event_child, &w); if (debug_threads) fprintf (stderr, "Signal %d for LWP %ld deferred (in jump pad)\n", WSTOPSIG (w), lwpid_of (event_child)); linux_resume_one_lwp (event_child, 0, 0, NULL); goto retry; } } if (event_child->collecting_fast_tracepoint) { if (debug_threads) fprintf (stderr, "\ LWP %ld was trying to move out of the jump pad (%d). \ Check if we're already there.\n", lwpid_of (event_child), event_child->collecting_fast_tracepoint); trace_event = 1; event_child->collecting_fast_tracepoint = linux_fast_tracepoint_collecting (event_child, NULL); if (event_child->collecting_fast_tracepoint != 1) { /* No longer need this breakpoint. */ if (event_child->exit_jump_pad_bkpt != NULL) { if (debug_threads) fprintf (stderr, "No longer need exit-jump-pad bkpt; removing it." "stopping all threads momentarily.\n"); /* Other running threads could hit this breakpoint. We don't handle moribund locations like GDB does, instead we always pause all threads when removing breakpoints, so that any step-over or decr_pc_after_break adjustment is always taken care of while the breakpoint is still inserted. */ stop_all_lwps (1, event_child); cancel_breakpoints (); delete_breakpoint (event_child->exit_jump_pad_bkpt); event_child->exit_jump_pad_bkpt = NULL; unstop_all_lwps (1, event_child); gdb_assert (event_child->suspended >= 0); } } if (event_child->collecting_fast_tracepoint == 0) { if (debug_threads) fprintf (stderr, "fast tracepoint finished " "collecting successfully.\n"); /* We may have a deferred signal to report. */ if (dequeue_one_deferred_signal (event_child, &w)) { if (debug_threads) fprintf (stderr, "dequeued one signal.\n"); } else if (debug_threads) { fprintf (stderr, "no deferred signals.\n"); if (stabilizing_threads) { ourstatus->kind = TARGET_WAITKIND_STOPPED; ourstatus->value.sig = TARGET_SIGNAL_0; return ptid_of (event_child); } } } } /* Check whether GDB would be interested in this event. */ /* If GDB is not interested in this signal, don't stop other threads, and don't report it to GDB. Just resume the inferior right away. We do this for threading-related signals as well as any that GDB specifically requested we ignore. But never ignore SIGSTOP if we sent it ourselves, and do not ignore signals when stepping - they may require special handling to skip the signal handler. */ /* FIXME drow/2002-06-09: Get signal numbers from the inferior's thread library? */ if (WIFSTOPPED (w) && current_inferior->last_resume_kind != resume_step && ( #if defined (USE_THREAD_DB) && defined (__SIGRTMIN) (current_process ()->private->thread_db != NULL && (WSTOPSIG (w) == __SIGRTMIN || WSTOPSIG (w) == __SIGRTMIN + 1)) || #endif (pass_signals[target_signal_from_host (WSTOPSIG (w))] && !(WSTOPSIG (w) == SIGSTOP && current_inferior->last_resume_kind == resume_stop)))) { siginfo_t info, *info_p; if (debug_threads) fprintf (stderr, "Ignored signal %d for LWP %ld.\n", WSTOPSIG (w), lwpid_of (event_child)); if (ptrace (PTRACE_GETSIGINFO, lwpid_of (event_child), 0, &info) == 0) info_p = &info; else info_p = NULL; linux_resume_one_lwp (event_child, event_child->stepping, WSTOPSIG (w), info_p); goto retry; } /* If GDB wanted this thread to single step, we always want to report the SIGTRAP, and let GDB handle it. Watchpoints should always be reported. So should signals we can't explain. A SIGTRAP we can't explain could be a GDB breakpoint --- we may or not support Z0 breakpoints. If we do, we're be able to handle GDB breakpoints on top of internal breakpoints, by handling the internal breakpoint and still reporting the event to GDB. If we don't, we're out of luck, GDB won't see the breakpoint hit. */ report_to_gdb = (!maybe_internal_trap || current_inferior->last_resume_kind == resume_step || event_child->stopped_by_watchpoint || (!step_over_finished && !bp_explains_trap && !trace_event) || gdb_breakpoint_here (event_child->stop_pc)); /* We found no reason GDB would want us to stop. We either hit one of our own breakpoints, or finished an internal step GDB shouldn't know about. */ if (!report_to_gdb) { if (debug_threads) { if (bp_explains_trap) fprintf (stderr, "Hit a gdbserver breakpoint.\n"); if (step_over_finished) fprintf (stderr, "Step-over finished.\n"); if (trace_event) fprintf (stderr, "Tracepoint event.\n"); } /* We're not reporting this breakpoint to GDB, so apply the decr_pc_after_break adjustment to the inferior's regcache ourselves. */ if (the_low_target.set_pc != NULL) { struct regcache *regcache = get_thread_regcache (get_lwp_thread (event_child), 1); (*the_low_target.set_pc) (regcache, event_child->stop_pc); } /* We may have finished stepping over a breakpoint. If so, we've stopped and suspended all LWPs momentarily except the stepping one. This is where we resume them all again. We're going to keep waiting, so use proceed, which handles stepping over the next breakpoint. */ if (debug_threads) fprintf (stderr, "proceeding all threads.\n"); if (step_over_finished) unsuspend_all_lwps (event_child); proceed_all_lwps (); goto retry; } if (debug_threads) { if (current_inferior->last_resume_kind == resume_step) fprintf (stderr, "GDB wanted to single-step, reporting event.\n"); if (event_child->stopped_by_watchpoint) fprintf (stderr, "Stopped by watchpoint.\n"); if (gdb_breakpoint_here (event_child->stop_pc)) fprintf (stderr, "Stopped by GDB breakpoint.\n"); if (debug_threads) fprintf (stderr, "Hit a non-gdbserver trap event.\n"); } /* Alright, we're going to report a stop. */ if (!non_stop && !stabilizing_threads) { /* In all-stop, stop all threads. */ stop_all_lwps (0, NULL); /* If we're not waiting for a specific LWP, choose an event LWP from among those that have had events. Giving equal priority to all LWPs that have had events helps prevent starvation. */ if (ptid_equal (ptid, minus_one_ptid)) { event_child->status_pending_p = 1; event_child->status_pending = w; select_event_lwp (&event_child); event_child->status_pending_p = 0; w = event_child->status_pending; } /* Now that we've selected our final event LWP, cancel any breakpoints in other LWPs that have hit a GDB breakpoint. See the comment in cancel_breakpoints_callback to find out why. */ find_inferior (&all_lwps, cancel_breakpoints_callback, event_child); /* Stabilize threads (move out of jump pads). */ stabilize_threads (); } else { /* If we just finished a step-over, then all threads had been momentarily paused. In all-stop, that's fine, we want threads stopped by now anyway. In non-stop, we need to re-resume threads that GDB wanted to be running. */ if (step_over_finished) unstop_all_lwps (1, event_child); } ourstatus->kind = TARGET_WAITKIND_STOPPED; /* Do this before the gdb_wants_all_stopped calls below, since they always set last_resume_kind to resume_stop. */ if (current_inferior->last_resume_kind == resume_stop && WSTOPSIG (w) == SIGSTOP) { /* A thread that has been requested to stop by GDB with vCont;t, and it stopped cleanly, so report as SIG0. The use of SIGSTOP is an implementation detail. */ ourstatus->value.sig = TARGET_SIGNAL_0; } else if (current_inferior->last_resume_kind == resume_stop && WSTOPSIG (w) != SIGSTOP) { /* A thread that has been requested to stop by GDB with vCont;t, but, it stopped for other reasons. */ ourstatus->value.sig = target_signal_from_host (WSTOPSIG (w)); } else { ourstatus->value.sig = target_signal_from_host (WSTOPSIG (w)); } gdb_assert (ptid_equal (step_over_bkpt, null_ptid)); if (stabilizing_threads) return ptid_of (event_child); if (!non_stop) { /* From GDB's perspective, all-stop mode always stops all threads implicitly. Tag all threads as "want-stopped". */ gdb_wants_all_stopped (); } else { /* We're reporting this LWP as stopped. Update it's "want-stopped" state to what the client wants, until it gets a new resume action. */ gdb_wants_lwp_stopped (&event_child->head); } if (debug_threads) fprintf (stderr, "linux_wait ret = %s, %d, %d\n", target_pid_to_str (ptid_of (event_child)), ourstatus->kind, ourstatus->value.sig); current_inferior->last_status = *ourstatus; return ptid_of (event_child); } /* Get rid of any pending event in the pipe. */ static void async_file_flush (void) { int ret; char buf; do ret = read (linux_event_pipe[0], &buf, 1); while (ret >= 0 || (ret == -1 && errno == EINTR)); } /* Put something in the pipe, so the event loop wakes up. */ static void async_file_mark (void) { int ret; async_file_flush (); do ret = write (linux_event_pipe[1], "+", 1); while (ret == 0 || (ret == -1 && errno == EINTR)); /* Ignore EAGAIN. If the pipe is full, the event loop will already be awakened anyway. */ } static ptid_t linux_wait (ptid_t ptid, struct target_waitstatus *ourstatus, int target_options) { ptid_t event_ptid; if (debug_threads) fprintf (stderr, "linux_wait: [%s]\n", target_pid_to_str (ptid)); /* Flush the async file first. */ if (target_is_async_p ()) async_file_flush (); event_ptid = linux_wait_1 (ptid, ourstatus, target_options); /* If at least one stop was reported, there may be more. A single SIGCHLD can signal more than one child stop. */ if (target_is_async_p () && (target_options & TARGET_WNOHANG) != 0 && !ptid_equal (event_ptid, null_ptid)) async_file_mark (); return event_ptid; } /* Send a signal to an LWP. */ static int kill_lwp (unsigned long lwpid, int signo) { /* Use tkill, if possible, in case we are using nptl threads. If tkill fails, then we are not using nptl threads and we should be using kill. */ #ifdef __NR_tkill { static int tkill_failed; if (!tkill_failed) { int ret; errno = 0; ret = syscall (__NR_tkill, lwpid, signo); if (errno != ENOSYS) return ret; tkill_failed = 1; } } #endif return kill (lwpid, signo); } static void send_sigstop (struct lwp_info *lwp) { int pid; pid = lwpid_of (lwp); /* If we already have a pending stop signal for this process, don't send another. */ if (lwp->stop_expected) { if (debug_threads) fprintf (stderr, "Have pending sigstop for lwp %d\n", pid); return; } if (debug_threads) fprintf (stderr, "Sending sigstop to lwp %d\n", pid); lwp->stop_expected = 1; kill_lwp (pid, SIGSTOP); } static int send_sigstop_callback (struct inferior_list_entry *entry, void *except) { struct lwp_info *lwp = (struct lwp_info *) entry; /* Ignore EXCEPT. */ if (lwp == except) return 0; if (lwp->stopped) return 0; send_sigstop (lwp); return 0; } /* Increment the suspend count of an LWP, and stop it, if not stopped yet. */ static int suspend_and_send_sigstop_callback (struct inferior_list_entry *entry, void *except) { struct lwp_info *lwp = (struct lwp_info *) entry; /* Ignore EXCEPT. */ if (lwp == except) return 0; lwp->suspended++; return send_sigstop_callback (entry, except); } static void mark_lwp_dead (struct lwp_info *lwp, int wstat) { /* It's dead, really. */ lwp->dead = 1; /* Store the exit status for later. */ lwp->status_pending_p = 1; lwp->status_pending = wstat; /* Prevent trying to stop it. */ lwp->stopped = 1; /* No further stops are expected from a dead lwp. */ lwp->stop_expected = 0; } static void wait_for_sigstop (struct inferior_list_entry *entry) { struct lwp_info *lwp = (struct lwp_info *) entry; struct thread_info *saved_inferior; int wstat; ptid_t saved_tid; ptid_t ptid; int pid; if (lwp->stopped) { if (debug_threads) fprintf (stderr, "wait_for_sigstop: LWP %ld already stopped\n", lwpid_of (lwp)); return; } saved_inferior = current_inferior; if (saved_inferior != NULL) saved_tid = ((struct inferior_list_entry *) saved_inferior)->id; else saved_tid = null_ptid; /* avoid bogus unused warning */ ptid = lwp->head.id; if (debug_threads) fprintf (stderr, "wait_for_sigstop: pulling one event\n"); pid = linux_wait_for_event (ptid, &wstat, __WALL); /* If we stopped with a non-SIGSTOP signal, save it for later and record the pending SIGSTOP. If the process exited, just return. */ if (WIFSTOPPED (wstat)) { if (debug_threads) fprintf (stderr, "LWP %ld stopped with signal %d\n", lwpid_of (lwp), WSTOPSIG (wstat)); if (WSTOPSIG (wstat) != SIGSTOP) { if (debug_threads) fprintf (stderr, "LWP %ld stopped with non-sigstop status %06x\n", lwpid_of (lwp), wstat); lwp->status_pending_p = 1; lwp->status_pending = wstat; } } else { if (debug_threads) fprintf (stderr, "Process %d exited while stopping LWPs\n", pid); lwp = find_lwp_pid (pid_to_ptid (pid)); if (lwp) { /* Leave this status pending for the next time we're able to report it. In the mean time, we'll report this lwp as dead to GDB, so GDB doesn't try to read registers and memory from it. This can only happen if this was the last thread of the process; otherwise, PID is removed from the thread tables before linux_wait_for_event returns. */ mark_lwp_dead (lwp, wstat); } } if (saved_inferior == NULL || linux_thread_alive (saved_tid)) current_inferior = saved_inferior; else { if (debug_threads) fprintf (stderr, "Previously current thread died.\n"); if (non_stop) { /* We can't change the current inferior behind GDB's back, otherwise, a subsequent command may apply to the wrong process. */ current_inferior = NULL; } else { /* Set a valid thread as current. */ set_desired_inferior (0); } } } /* Returns true if LWP ENTRY is stopped in a jump pad, and we can't move it out, because we need to report the stop event to GDB. For example, if the user puts a breakpoint in the jump pad, it's because she wants to debug it. */ static int stuck_in_jump_pad_callback (struct inferior_list_entry *entry, void *data) { struct lwp_info *lwp = (struct lwp_info *) entry; struct thread_info *thread = get_lwp_thread (lwp); gdb_assert (lwp->suspended == 0); gdb_assert (lwp->stopped); /* Allow debugging the jump pad, gdb_collect, etc.. */ return (supports_fast_tracepoints () && in_process_agent_loaded () && (gdb_breakpoint_here (lwp->stop_pc) || lwp->stopped_by_watchpoint || thread->last_resume_kind == resume_step) && linux_fast_tracepoint_collecting (lwp, NULL)); } static void move_out_of_jump_pad_callback (struct inferior_list_entry *entry) { struct lwp_info *lwp = (struct lwp_info *) entry; struct thread_info *thread = get_lwp_thread (lwp); int *wstat; gdb_assert (lwp->suspended == 0); gdb_assert (lwp->stopped); wstat = lwp->status_pending_p ? &lwp->status_pending : NULL; /* Allow debugging the jump pad, gdb_collect, etc. */ if (!gdb_breakpoint_here (lwp->stop_pc) && !lwp->stopped_by_watchpoint && thread->last_resume_kind != resume_step && maybe_move_out_of_jump_pad (lwp, wstat)) { if (debug_threads) fprintf (stderr, "LWP %ld needs stabilizing (in jump pad)\n", lwpid_of (lwp)); if (wstat) { lwp->status_pending_p = 0; enqueue_one_deferred_signal (lwp, wstat); if (debug_threads) fprintf (stderr, "Signal %d for LWP %ld deferred " "(in jump pad)\n", WSTOPSIG (*wstat), lwpid_of (lwp)); } linux_resume_one_lwp (lwp, 0, 0, NULL); } else lwp->suspended++; } static int lwp_running (struct inferior_list_entry *entry, void *data) { struct lwp_info *lwp = (struct lwp_info *) entry; if (lwp->dead) return 0; if (lwp->stopped) return 0; return 1; } /* Stop all lwps that aren't stopped yet, except EXCEPT, if not NULL. If SUSPEND, then also increase the suspend count of every LWP, except EXCEPT. */ static void stop_all_lwps (int suspend, struct lwp_info *except) { stopping_threads = 1; if (suspend) find_inferior (&all_lwps, suspend_and_send_sigstop_callback, except); else find_inferior (&all_lwps, send_sigstop_callback, except); for_each_inferior (&all_lwps, wait_for_sigstop); stopping_threads = 0; } /* Resume execution of the inferior process. If STEP is nonzero, single-step it. If SIGNAL is nonzero, give it that signal. */ static void linux_resume_one_lwp (struct lwp_info *lwp, int step, int signal, siginfo_t *info) { struct thread_info *saved_inferior; int fast_tp_collecting; if (lwp->stopped == 0) return; fast_tp_collecting = lwp->collecting_fast_tracepoint; gdb_assert (!stabilizing_threads || fast_tp_collecting); /* Cancel actions that rely on GDB not changing the PC (e.g., the user used the "jump" command, or "set $pc = foo"). */ if (lwp->stop_pc != get_pc (lwp)) { /* Collecting 'while-stepping' actions doesn't make sense anymore. */ release_while_stepping_state_list (get_lwp_thread (lwp)); } /* If we have pending signals or status, and a new signal, enqueue the signal. Also enqueue the signal if we are waiting to reinsert a breakpoint; it will be picked up again below. */ if (signal != 0 && (lwp->status_pending_p || lwp->pending_signals != NULL || lwp->bp_reinsert != 0 || fast_tp_collecting)) { struct pending_signals *p_sig; p_sig = xmalloc (sizeof (*p_sig)); p_sig->prev = lwp->pending_signals; p_sig->signal = signal; if (info == NULL) memset (&p_sig->info, 0, sizeof (siginfo_t)); else memcpy (&p_sig->info, info, sizeof (siginfo_t)); lwp->pending_signals = p_sig; } if (lwp->status_pending_p) { if (debug_threads) fprintf (stderr, "Not resuming lwp %ld (%s, signal %d, stop %s);" " has pending status\n", lwpid_of (lwp), step ? "step" : "continue", signal, lwp->stop_expected ? "expected" : "not expected"); return; } saved_inferior = current_inferior; current_inferior = get_lwp_thread (lwp); if (debug_threads) fprintf (stderr, "Resuming lwp %ld (%s, signal %d, stop %s)\n", lwpid_of (lwp), step ? "step" : "continue", signal, lwp->stop_expected ? "expected" : "not expected"); /* This bit needs some thinking about. If we get a signal that we must report while a single-step reinsert is still pending, we often end up resuming the thread. It might be better to (ew) allow a stack of pending events; then we could be sure that the reinsert happened right away and not lose any signals. Making this stack would also shrink the window in which breakpoints are uninserted (see comment in linux_wait_for_lwp) but not enough for complete correctness, so it won't solve that problem. It may be worthwhile just to solve this one, however. */ if (lwp->bp_reinsert != 0) { if (debug_threads) fprintf (stderr, " pending reinsert at 0x%s\n", paddress (lwp->bp_reinsert)); if (lwp->bp_reinsert != 0 && can_hardware_single_step ()) { if (fast_tp_collecting == 0) { if (step == 0) fprintf (stderr, "BAD - reinserting but not stepping.\n"); if (lwp->suspended) fprintf (stderr, "BAD - reinserting and suspended(%d).\n", lwp->suspended); } step = 1; } /* Postpone any pending signal. It was enqueued above. */ signal = 0; } if (fast_tp_collecting == 1) { if (debug_threads) fprintf (stderr, "\ lwp %ld wants to get out of fast tracepoint jump pad (exit-jump-pad-bkpt)\n", lwpid_of (lwp)); /* Postpone any pending signal. It was enqueued above. */ signal = 0; } else if (fast_tp_collecting == 2) { if (debug_threads) fprintf (stderr, "\ lwp %ld wants to get out of fast tracepoint jump pad single-stepping\n", lwpid_of (lwp)); if (can_hardware_single_step ()) step = 1; else fatal ("moving out of jump pad single-stepping" " not implemented on this target"); /* Postpone any pending signal. It was enqueued above. */ signal = 0; } /* If we have while-stepping actions in this thread set it stepping. If we have a signal to deliver, it may or may not be set to SIG_IGN, we don't know. Assume so, and allow collecting while-stepping into a signal handler. A possible smart thing to do would be to set an internal breakpoint at the signal return address, continue, and carry on catching this while-stepping action only when that breakpoint is hit. A future enhancement. */ if (get_lwp_thread (lwp)->while_stepping != NULL && can_hardware_single_step ()) { if (debug_threads) fprintf (stderr, "lwp %ld has a while-stepping action -> forcing step.\n", lwpid_of (lwp)); step = 1; } if (debug_threads && the_low_target.get_pc != NULL) { struct regcache *regcache = get_thread_regcache (current_inferior, 1); CORE_ADDR pc = (*the_low_target.get_pc) (regcache); fprintf (stderr, " resuming from pc 0x%lx\n", (long) pc); } /* If we have pending signals, consume one unless we are trying to reinsert a breakpoint or we're trying to finish a fast tracepoint collect. */ if (lwp->pending_signals != NULL && lwp->bp_reinsert == 0 && fast_tp_collecting == 0) { struct pending_signals **p_sig; p_sig = &lwp->pending_signals; while ((*p_sig)->prev != NULL) p_sig = &(*p_sig)->prev; signal = (*p_sig)->signal; if ((*p_sig)->info.si_signo != 0) ptrace (PTRACE_SETSIGINFO, lwpid_of (lwp), 0, &(*p_sig)->info); free (*p_sig); *p_sig = NULL; } if (the_low_target.prepare_to_resume != NULL) the_low_target.prepare_to_resume (lwp); regcache_invalidate_one ((struct inferior_list_entry *) get_lwp_thread (lwp)); errno = 0; lwp->stopped = 0; lwp->stopped_by_watchpoint = 0; lwp->stepping = step; ptrace (step ? PTRACE_SINGLESTEP : PTRACE_CONT, lwpid_of (lwp), 0, /* Coerce to a uintptr_t first to avoid potential gcc warning of coercing an 8 byte integer to a 4 byte pointer. */ (PTRACE_ARG4_TYPE) (uintptr_t) signal); current_inferior = saved_inferior; if (errno) { /* ESRCH from ptrace either means that the thread was already running (an error) or that it is gone (a race condition). If it's gone, we will get a notification the next time we wait, so we can ignore the error. We could differentiate these two, but it's tricky without waiting; the thread still exists as a zombie, so sending it signal 0 would succeed. So just ignore ESRCH. */ if (errno == ESRCH) return; perror_with_name ("ptrace"); } } struct thread_resume_array { struct thread_resume *resume; size_t n; }; /* This function is called once per thread. We look up the thread in RESUME_PTR, and mark the thread with a pointer to the appropriate resume request. This algorithm is O(threads * resume elements), but resume elements is small (and will remain small at least until GDB supports thread suspension). */ static int linux_set_resume_request (struct inferior_list_entry *entry, void *arg) { struct lwp_info *lwp; struct thread_info *thread; int ndx; struct thread_resume_array *r; thread = (struct thread_info *) entry; lwp = get_thread_lwp (thread); r = arg; for (ndx = 0; ndx < r->n; ndx++) { ptid_t ptid = r->resume[ndx].thread; if (ptid_equal (ptid, minus_one_ptid) || ptid_equal (ptid, entry->id) || (ptid_is_pid (ptid) && (ptid_get_pid (ptid) == pid_of (lwp))) || (ptid_get_lwp (ptid) == -1 && (ptid_get_pid (ptid) == pid_of (lwp)))) { if (r->resume[ndx].kind == resume_stop && thread->last_resume_kind == resume_stop) { if (debug_threads) fprintf (stderr, "already %s LWP %ld at GDB's request\n", thread->last_status.kind == TARGET_WAITKIND_STOPPED ? "stopped" : "stopping", lwpid_of (lwp)); continue; } lwp->resume = &r->resume[ndx]; thread->last_resume_kind = lwp->resume->kind; /* If we had a deferred signal to report, dequeue one now. This can happen if LWP gets more than one signal while trying to get out of a jump pad. */ if (lwp->stopped && !lwp->status_pending_p && dequeue_one_deferred_signal (lwp, &lwp->status_pending)) { lwp->status_pending_p = 1; if (debug_threads) fprintf (stderr, "Dequeueing deferred signal %d for LWP %ld, " "leaving status pending.\n", WSTOPSIG (lwp->status_pending), lwpid_of (lwp)); } return 0; } } /* No resume action for this thread. */ lwp->resume = NULL; return 0; } /* Set *FLAG_P if this lwp has an interesting status pending. */ static int resume_status_pending_p (struct inferior_list_entry *entry, void *flag_p) { struct lwp_info *lwp = (struct lwp_info *) entry; /* LWPs which will not be resumed are not interesting, because we might not wait for them next time through linux_wait. */ if (lwp->resume == NULL) return 0; if (lwp->status_pending_p) * (int *) flag_p = 1; return 0; } /* Return 1 if this lwp that GDB wants running is stopped at an internal breakpoint that we need to step over. It assumes that any required STOP_PC adjustment has already been propagated to the inferior's regcache. */ static int need_step_over_p (struct inferior_list_entry *entry, void *dummy) { struct lwp_info *lwp = (struct lwp_info *) entry; struct thread_info *thread; struct thread_info *saved_inferior; CORE_ADDR pc; /* LWPs which will not be resumed are not interesting, because we might not wait for them next time through linux_wait. */ if (!lwp->stopped) { if (debug_threads) fprintf (stderr, "Need step over [LWP %ld]? Ignoring, not stopped\n", lwpid_of (lwp)); return 0; } thread = get_lwp_thread (lwp); if (thread->last_resume_kind == resume_stop) { if (debug_threads) fprintf (stderr, "Need step over [LWP %ld]? Ignoring, should remain stopped\n", lwpid_of (lwp)); return 0; } gdb_assert (lwp->suspended >= 0); if (lwp->suspended) { if (debug_threads) fprintf (stderr, "Need step over [LWP %ld]? Ignoring, suspended\n", lwpid_of (lwp)); return 0; } if (!lwp->need_step_over) { if (debug_threads) fprintf (stderr, "Need step over [LWP %ld]? No\n", lwpid_of (lwp)); } if (lwp->status_pending_p) { if (debug_threads) fprintf (stderr, "Need step over [LWP %ld]? Ignoring, has pending status.\n", lwpid_of (lwp)); return 0; } /* Note: PC, not STOP_PC. Either GDB has adjusted the PC already, or we have. */ pc = get_pc (lwp); /* If the PC has changed since we stopped, then don't do anything, and let the breakpoint/tracepoint be hit. This happens if, for instance, GDB handled the decr_pc_after_break subtraction itself, GDB is OOL stepping this thread, or the user has issued a "jump" command, or poked thread's registers herself. */ if (pc != lwp->stop_pc) { if (debug_threads) fprintf (stderr, "Need step over [LWP %ld]? Cancelling, PC was changed. " "Old stop_pc was 0x%s, PC is now 0x%s\n", lwpid_of (lwp), paddress (lwp->stop_pc), paddress (pc)); lwp->need_step_over = 0; return 0; } saved_inferior = current_inferior; current_inferior = thread; /* We can only step over breakpoints we know about. */ if (breakpoint_here (pc) || fast_tracepoint_jump_here (pc)) { /* Don't step over a breakpoint that GDB expects to hit though. */ if (gdb_breakpoint_here (pc)) { if (debug_threads) fprintf (stderr, "Need step over [LWP %ld]? yes, but found" " GDB breakpoint at 0x%s; skipping step over\n", lwpid_of (lwp), paddress (pc)); current_inferior = saved_inferior; return 0; } else { if (debug_threads) fprintf (stderr, "Need step over [LWP %ld]? yes, found breakpoint at 0x%s\n", lwpid_of (lwp), paddress (pc)); /* We've found an lwp that needs stepping over --- return 1 so that find_inferior stops looking. */ current_inferior = saved_inferior; /* If the step over is cancelled, this is set again. */ lwp->need_step_over = 0; return 1; } } current_inferior = saved_inferior; if (debug_threads) fprintf (stderr, "Need step over [LWP %ld]? No, no breakpoint found at 0x%s\n", lwpid_of (lwp), paddress (pc)); return 0; } /* Start a step-over operation on LWP. When LWP stopped at a breakpoint, to make progress, we need to remove the breakpoint out of the way. If we let other threads run while we do that, they may pass by the breakpoint location and miss hitting it. To avoid that, a step-over momentarily stops all threads while LWP is single-stepped while the breakpoint is temporarily uninserted from the inferior. When the single-step finishes, we reinsert the breakpoint, and let all threads that are supposed to be running, run again. On targets that don't support hardware single-step, we don't currently support full software single-stepping. Instead, we only support stepping over the thread event breakpoint, by asking the low target where to place a reinsert breakpoint. Since this routine assumes the breakpoint being stepped over is a thread event breakpoint, it usually assumes the return address of the current function is a good enough place to set the reinsert breakpoint. */ static int start_step_over (struct lwp_info *lwp) { struct thread_info *saved_inferior; CORE_ADDR pc; int step; if (debug_threads) fprintf (stderr, "Starting step-over on LWP %ld. Stopping all threads\n", lwpid_of (lwp)); stop_all_lwps (1, lwp); gdb_assert (lwp->suspended == 0); if (debug_threads) fprintf (stderr, "Done stopping all threads for step-over.\n"); /* Note, we should always reach here with an already adjusted PC, either by GDB (if we're resuming due to GDB's request), or by our caller, if we just finished handling an internal breakpoint GDB shouldn't care about. */ pc = get_pc (lwp); saved_inferior = current_inferior; current_inferior = get_lwp_thread (lwp); lwp->bp_reinsert = pc; uninsert_breakpoints_at (pc); uninsert_fast_tracepoint_jumps_at (pc); if (can_hardware_single_step ()) { step = 1; } else { CORE_ADDR raddr = (*the_low_target.breakpoint_reinsert_addr) (); set_reinsert_breakpoint (raddr); step = 0; } current_inferior = saved_inferior; linux_resume_one_lwp (lwp, step, 0, NULL); /* Require next event from this LWP. */ step_over_bkpt = lwp->head.id; return 1; } /* Finish a step-over. Reinsert the breakpoint we had uninserted in start_step_over, if still there, and delete any reinsert breakpoints we've set, on non hardware single-step targets. */ static int finish_step_over (struct lwp_info *lwp) { if (lwp->bp_reinsert != 0) { if (debug_threads) fprintf (stderr, "Finished step over.\n"); /* Reinsert any breakpoint at LWP->BP_REINSERT. Note that there may be no breakpoint to reinsert there by now. */ reinsert_breakpoints_at (lwp->bp_reinsert); reinsert_fast_tracepoint_jumps_at (lwp->bp_reinsert); lwp->bp_reinsert = 0; /* Delete any software-single-step reinsert breakpoints. No longer needed. We don't have to worry about other threads hitting this trap, and later not being able to explain it, because we were stepping over a breakpoint, and we hold all threads but LWP stopped while doing that. */ if (!can_hardware_single_step ()) delete_reinsert_breakpoints (); step_over_bkpt = null_ptid; return 1; } else return 0; } /* This function is called once per thread. We check the thread's resume request, which will tell us whether to resume, step, or leave the thread stopped; and what signal, if any, it should be sent. For threads which we aren't explicitly told otherwise, we preserve the stepping flag; this is used for stepping over gdbserver-placed breakpoints. If pending_flags was set in any thread, we queue any needed signals, since we won't actually resume. We already have a pending event to report, so we don't need to preserve any step requests; they should be re-issued if necessary. */ static int linux_resume_one_thread (struct inferior_list_entry *entry, void *arg) { struct lwp_info *lwp; struct thread_info *thread; int step; int leave_all_stopped = * (int *) arg; int leave_pending; thread = (struct thread_info *) entry; lwp = get_thread_lwp (thread); if (lwp->resume == NULL) return 0; if (lwp->resume->kind == resume_stop) { if (debug_threads) fprintf (stderr, "resume_stop request for LWP %ld\n", lwpid_of (lwp)); if (!lwp->stopped) { if (debug_threads) fprintf (stderr, "stopping LWP %ld\n", lwpid_of (lwp)); /* Stop the thread, and wait for the event asynchronously, through the event loop. */ send_sigstop (lwp); } else { if (debug_threads) fprintf (stderr, "already stopped LWP %ld\n", lwpid_of (lwp)); /* The LWP may have been stopped in an internal event that was not meant to be notified back to GDB (e.g., gdbserver breakpoint), so we should be reporting a stop event in this case too. */ /* If the thread already has a pending SIGSTOP, this is a no-op. Otherwise, something later will presumably resume the thread and this will cause it to cancel any pending operation, due to last_resume_kind == resume_stop. If the thread already has a pending status to report, we will still report it the next time we wait - see status_pending_p_callback. */ send_sigstop (lwp); } /* For stop requests, we're done. */ lwp->resume = NULL; thread->last_status.kind = TARGET_WAITKIND_IGNORE; return 0; } /* If this thread which is about to be resumed has a pending status, then don't resume any threads - we can just report the pending status. Make sure to queue any signals that would otherwise be sent. In all-stop mode, we do this decision based on if *any* thread has a pending status. If there's a thread that needs the step-over-breakpoint dance, then don't resume any other thread but that particular one. */ leave_pending = (lwp->status_pending_p || leave_all_stopped); if (!leave_pending) { if (debug_threads) fprintf (stderr, "resuming LWP %ld\n", lwpid_of (lwp)); step = (lwp->resume->kind == resume_step); linux_resume_one_lwp (lwp, step, lwp->resume->sig, NULL); } else { if (debug_threads) fprintf (stderr, "leaving LWP %ld stopped\n", lwpid_of (lwp)); /* If we have a new signal, enqueue the signal. */ if (lwp->resume->sig != 0) { struct pending_signals *p_sig; p_sig = xmalloc (sizeof (*p_sig)); p_sig->prev = lwp->pending_signals; p_sig->signal = lwp->resume->sig; memset (&p_sig->info, 0, sizeof (siginfo_t)); /* If this is the same signal we were previously stopped by, make sure to queue its siginfo. We can ignore the return value of ptrace; if it fails, we'll skip PTRACE_SETSIGINFO. */ if (WIFSTOPPED (lwp->last_status) && WSTOPSIG (lwp->last_status) == lwp->resume->sig) ptrace (PTRACE_GETSIGINFO, lwpid_of (lwp), 0, &p_sig->info); lwp->pending_signals = p_sig; } } thread->last_status.kind = TARGET_WAITKIND_IGNORE; lwp->resume = NULL; return 0; } static void linux_resume (struct thread_resume *resume_info, size_t n) { struct thread_resume_array array = { resume_info, n }; struct lwp_info *need_step_over = NULL; int any_pending; int leave_all_stopped; find_inferior (&all_threads, linux_set_resume_request, &array); /* If there is a thread which would otherwise be resumed, which has a pending status, then don't resume any threads - we can just report the pending status. Make sure to queue any signals that would otherwise be sent. In non-stop mode, we'll apply this logic to each thread individually. We consume all pending events before considering to start a step-over (in all-stop). */ any_pending = 0; if (!non_stop) find_inferior (&all_lwps, resume_status_pending_p, &any_pending); /* If there is a thread which would otherwise be resumed, which is stopped at a breakpoint that needs stepping over, then don't resume any threads - have it step over the breakpoint with all other threads stopped, then resume all threads again. Make sure to queue any signals that would otherwise be delivered or queued. */ if (!any_pending && supports_breakpoints ()) need_step_over = (struct lwp_info *) find_inferior (&all_lwps, need_step_over_p, NULL); leave_all_stopped = (need_step_over != NULL || any_pending); if (debug_threads) { if (need_step_over != NULL) fprintf (stderr, "Not resuming all, need step over\n"); else if (any_pending) fprintf (stderr, "Not resuming, all-stop and found " "an LWP with pending status\n"); else fprintf (stderr, "Resuming, no pending status or step over needed\n"); } /* Even if we're leaving threads stopped, queue all signals we'd otherwise deliver. */ find_inferior (&all_threads, linux_resume_one_thread, &leave_all_stopped); if (need_step_over) start_step_over (need_step_over); } /* This function is called once per thread. We check the thread's last resume request, which will tell us whether to resume, step, or leave the thread stopped. Any signal the client requested to be delivered has already been enqueued at this point. If any thread that GDB wants running is stopped at an internal breakpoint that needs stepping over, we start a step-over operation on that particular thread, and leave all others stopped. */ static int proceed_one_lwp (struct inferior_list_entry *entry, void *except) { struct lwp_info *lwp = (struct lwp_info *) entry; struct thread_info *thread; int step; if (lwp == except) return 0; if (debug_threads) fprintf (stderr, "proceed_one_lwp: lwp %ld\n", lwpid_of (lwp)); if (!lwp->stopped) { if (debug_threads) fprintf (stderr, " LWP %ld already running\n", lwpid_of (lwp)); return 0; } thread = get_lwp_thread (lwp); if (thread->last_resume_kind == resume_stop && thread->last_status.kind != TARGET_WAITKIND_IGNORE) { if (debug_threads) fprintf (stderr, " client wants LWP to remain %ld stopped\n", lwpid_of (lwp)); return 0; } if (lwp->status_pending_p) { if (debug_threads) fprintf (stderr, " LWP %ld has pending status, leaving stopped\n", lwpid_of (lwp)); return 0; } gdb_assert (lwp->suspended >= 0); if (lwp->suspended) { if (debug_threads) fprintf (stderr, " LWP %ld is suspended\n", lwpid_of (lwp)); return 0; } if (thread->last_resume_kind == resume_stop) { /* We haven't reported this LWP as stopped yet (otherwise, the last_status.kind check above would catch it, and we wouldn't reach here. This LWP may have been momentarily paused by a stop_all_lwps call while handling for example, another LWP's step-over. In that case, the pending expected SIGSTOP signal that was queued at vCont;t handling time will have already been consumed by wait_for_sigstop, and so we need to requeue another one here. Note that if the LWP already has a SIGSTOP pending, this is a no-op. */ if (debug_threads) fprintf (stderr, "Client wants LWP %ld to stop. " "Making sure it has a SIGSTOP pending\n", lwpid_of (lwp)); send_sigstop (lwp); } step = thread->last_resume_kind == resume_step; linux_resume_one_lwp (lwp, step, 0, NULL); return 0; } static int unsuspend_and_proceed_one_lwp (struct inferior_list_entry *entry, void *except) { struct lwp_info *lwp = (struct lwp_info *) entry; if (lwp == except) return 0; lwp->suspended--; gdb_assert (lwp->suspended >= 0); return proceed_one_lwp (entry, except); } /* When we finish a step-over, set threads running again. If there's another thread that may need a step-over, now's the time to start it. Eventually, we'll move all threads past their breakpoints. */ static void proceed_all_lwps (void) { struct lwp_info *need_step_over; /* If there is a thread which would otherwise be resumed, which is stopped at a breakpoint that needs stepping over, then don't resume any threads - have it step over the breakpoint with all other threads stopped, then resume all threads again. */ if (supports_breakpoints ()) { need_step_over = (struct lwp_info *) find_inferior (&all_lwps, need_step_over_p, NULL); if (need_step_over != NULL) { if (debug_threads) fprintf (stderr, "proceed_all_lwps: found " "thread %ld needing a step-over\n", lwpid_of (need_step_over)); start_step_over (need_step_over); return; } } if (debug_threads) fprintf (stderr, "Proceeding, no step-over needed\n"); find_inferior (&all_lwps, proceed_one_lwp, NULL); } /* Stopped LWPs that the client wanted to be running, that don't have pending statuses, are set to run again, except for EXCEPT, if not NULL. This undoes a stop_all_lwps call. */ static void unstop_all_lwps (int unsuspend, struct lwp_info *except) { if (debug_threads) { if (except) fprintf (stderr, "unstopping all lwps, except=(LWP %ld)\n", lwpid_of (except)); else fprintf (stderr, "unstopping all lwps\n"); } if (unsuspend) find_inferior (&all_lwps, unsuspend_and_proceed_one_lwp, except); else find_inferior (&all_lwps, proceed_one_lwp, except); } #ifdef HAVE_LINUX_USRREGS int register_addr (int regnum) { int addr; if (regnum < 0 || regnum >= the_low_target.num_regs) error ("Invalid register number %d.", regnum); addr = the_low_target.regmap[regnum]; return addr; } /* Fetch one register. */ static void fetch_register (struct regcache *regcache, int regno) { CORE_ADDR regaddr; int i, size; char *buf; int pid; if (regno >= the_low_target.num_regs) return; if ((*the_low_target.cannot_fetch_register) (regno)) return; regaddr = register_addr (regno); if (regaddr == -1) return; pid = lwpid_of (get_thread_lwp (current_inferior)); size = ((register_size (regno) + sizeof (PTRACE_XFER_TYPE) - 1) & - sizeof (PTRACE_XFER_TYPE)); buf = alloca (size); for (i = 0; i < size; i += sizeof (PTRACE_XFER_TYPE)) { errno = 0; *(PTRACE_XFER_TYPE *) (buf + i) = ptrace (PTRACE_PEEKUSER, pid, /* Coerce to a uintptr_t first to avoid potential gcc warning of coercing an 8 byte integer to a 4 byte pointer. */ (PTRACE_ARG3_TYPE) (uintptr_t) regaddr, 0); regaddr += sizeof (PTRACE_XFER_TYPE); if (errno != 0) error ("reading register %d: %s", regno, strerror (errno)); } if (the_low_target.supply_ptrace_register) the_low_target.supply_ptrace_register (regcache, regno, buf); else supply_register (regcache, regno, buf); } /* Fetch all registers, or just one, from the child process. */ static void usr_fetch_inferior_registers (struct regcache *regcache, int regno) { if (regno == -1) for (regno = 0; regno < the_low_target.num_regs; regno++) fetch_register (regcache, regno); else fetch_register (regcache, regno); } /* Store our register values back into the inferior. If REGNO is -1, do this for all registers. Otherwise, REGNO specifies which register (so we can save time). */ static void usr_store_inferior_registers (struct regcache *regcache, int regno) { CORE_ADDR regaddr; int i, size; char *buf; int pid; if (regno >= 0) { if (regno >= the_low_target.num_regs) return; if ((*the_low_target.cannot_store_register) (regno) == 1) return; regaddr = register_addr (regno); if (regaddr == -1) return; errno = 0; size = (register_size (regno) + sizeof (PTRACE_XFER_TYPE) - 1) & - sizeof (PTRACE_XFER_TYPE); buf = alloca (size); memset (buf, 0, size); if (the_low_target.collect_ptrace_register) the_low_target.collect_ptrace_register (regcache, regno, buf); else collect_register (regcache, regno, buf); pid = lwpid_of (get_thread_lwp (current_inferior)); for (i = 0; i < size; i += sizeof (PTRACE_XFER_TYPE)) { errno = 0; ptrace (PTRACE_POKEUSER, pid, /* Coerce to a uintptr_t first to avoid potential gcc warning about coercing an 8 byte integer to a 4 byte pointer. */ (PTRACE_ARG3_TYPE) (uintptr_t) regaddr, (PTRACE_ARG4_TYPE) *(PTRACE_XFER_TYPE *) (buf + i)); if (errno != 0) { /* At this point, ESRCH should mean the process is already gone, in which case we simply ignore attempts to change its registers. See also the related comment in linux_resume_one_lwp. */ if (errno == ESRCH) return; if ((*the_low_target.cannot_store_register) (regno) == 0) error ("writing register %d: %s", regno, strerror (errno)); } regaddr += sizeof (PTRACE_XFER_TYPE); } } else for (regno = 0; regno < the_low_target.num_regs; regno++) usr_store_inferior_registers (regcache, regno); } #endif /* HAVE_LINUX_USRREGS */ #ifdef HAVE_LINUX_REGSETS static int regsets_fetch_inferior_registers (struct regcache *regcache) { struct regset_info *regset; int saw_general_regs = 0; int pid; struct iovec iov; regset = target_regsets; pid = lwpid_of (get_thread_lwp (current_inferior)); while (regset->size >= 0) { void *buf, *data; int nt_type, res; if (regset->size == 0 || disabled_regsets[regset - target_regsets]) { regset ++; continue; } buf = xmalloc (regset->size); nt_type = regset->nt_type; if (nt_type) { iov.iov_base = buf; iov.iov_len = regset->size; data = (void *) &iov; } else data = buf; #ifndef __sparc__ res = ptrace (regset->get_request, pid, nt_type, data); #else res = ptrace (regset->get_request, pid, data, nt_type); #endif if (res < 0) { if (errno == EIO) { /* If we get EIO on a regset, do not try it again for this process. */ disabled_regsets[regset - target_regsets] = 1; free (buf); continue; } else { char s[256]; sprintf (s, "ptrace(regsets_fetch_inferior_registers) PID=%d", pid); perror (s); } } else if (regset->type == GENERAL_REGS) saw_general_regs = 1; regset->store_function (regcache, buf); regset ++; free (buf); } if (saw_general_regs) return 0; else return 1; } static int regsets_store_inferior_registers (struct regcache *regcache) { struct regset_info *regset; int saw_general_regs = 0; int pid; struct iovec iov; regset = target_regsets; pid = lwpid_of (get_thread_lwp (current_inferior)); while (regset->size >= 0) { void *buf, *data; int nt_type, res; if (regset->size == 0 || disabled_regsets[regset - target_regsets]) { regset ++; continue; } buf = xmalloc (regset->size); /* First fill the buffer with the current register set contents, in case there are any items in the kernel's regset that are not in gdbserver's regcache. */ nt_type = regset->nt_type; if (nt_type) { iov.iov_base = buf; iov.iov_len = regset->size; data = (void *) &iov; } else data = buf; #ifndef __sparc__ res = ptrace (regset->get_request, pid, nt_type, data); #else res = ptrace (regset->get_request, pid, &iov, data); #endif if (res == 0) { /* Then overlay our cached registers on that. */ regset->fill_function (regcache, buf); /* Only now do we write the register set. */ #ifndef __sparc__ res = ptrace (regset->set_request, pid, nt_type, data); #else res = ptrace (regset->set_request, pid, data, nt_type); #endif } if (res < 0) { if (errno == EIO) { /* If we get EIO on a regset, do not try it again for this process. */ disabled_regsets[regset - target_regsets] = 1; free (buf); continue; } else if (errno == ESRCH) { /* At this point, ESRCH should mean the process is already gone, in which case we simply ignore attempts to change its registers. See also the related comment in linux_resume_one_lwp. */ free (buf); return 0; } else { perror ("Warning: ptrace(regsets_store_inferior_registers)"); } } else if (regset->type == GENERAL_REGS) saw_general_regs = 1; regset ++; free (buf); } if (saw_general_regs) return 0; else return 1; return 0; } #endif /* HAVE_LINUX_REGSETS */ void linux_fetch_registers (struct regcache *regcache, int regno) { #ifdef HAVE_LINUX_REGSETS if (regsets_fetch_inferior_registers (regcache) == 0) return; #endif #ifdef HAVE_LINUX_USRREGS usr_fetch_inferior_registers (regcache, regno); #endif } void linux_store_registers (struct regcache *regcache, int regno) { #ifdef HAVE_LINUX_REGSETS if (regsets_store_inferior_registers (regcache) == 0) return; #endif #ifdef HAVE_LINUX_USRREGS usr_store_inferior_registers (regcache, regno); #endif } /* Copy LEN bytes from inferior's memory starting at MEMADDR to debugger memory starting at MYADDR. */ static int linux_read_memory (CORE_ADDR memaddr, unsigned char *myaddr, int len) { register int i; /* Round starting address down to longword boundary. */ register CORE_ADDR addr = memaddr & -(CORE_ADDR) sizeof (PTRACE_XFER_TYPE); /* Round ending address up; get number of longwords that makes. */ register int count = (((memaddr + len) - addr) + sizeof (PTRACE_XFER_TYPE) - 1) / sizeof (PTRACE_XFER_TYPE); /* Allocate buffer of that many longwords. */ register PTRACE_XFER_TYPE *buffer = (PTRACE_XFER_TYPE *) alloca (count * sizeof (PTRACE_XFER_TYPE)); int fd; char filename[64]; int pid = lwpid_of (get_thread_lwp (current_inferior)); /* Try using /proc. Don't bother for one word. */ if (len >= 3 * sizeof (long)) { /* We could keep this file open and cache it - possibly one per thread. That requires some juggling, but is even faster. */ sprintf (filename, "/proc/%d/mem", pid); fd = open (filename, O_RDONLY | O_LARGEFILE); if (fd == -1) goto no_proc; /* If pread64 is available, use it. It's faster if the kernel supports it (only one syscall), and it's 64-bit safe even on 32-bit platforms (for instance, SPARC debugging a SPARC64 application). */ #ifdef HAVE_PREAD64 if (pread64 (fd, myaddr, len, memaddr) != len) #else if (lseek (fd, memaddr, SEEK_SET) == -1 || read (fd, myaddr, len) != len) #endif { close (fd); goto no_proc; } close (fd); return 0; } no_proc: /* Read all the longwords */ for (i = 0; i < count; i++, addr += sizeof (PTRACE_XFER_TYPE)) { errno = 0; /* Coerce the 3rd arg to a uintptr_t first to avoid potential gcc warning about coercing an 8 byte integer to a 4 byte pointer. */ buffer[i] = ptrace (PTRACE_PEEKTEXT, pid, (PTRACE_ARG3_TYPE) (uintptr_t) addr, 0); if (errno) return errno; } /* Copy appropriate bytes out of the buffer. */ memcpy (myaddr, (char *) buffer + (memaddr & (sizeof (PTRACE_XFER_TYPE) - 1)), len); return 0; } /* Copy LEN bytes of data from debugger memory at MYADDR to inferior's memory at MEMADDR. On failure (cannot write to the inferior) returns the value of errno. */ static int linux_write_memory (CORE_ADDR memaddr, const unsigned char *myaddr, int len) { register int i; /* Round starting address down to longword boundary. */ register CORE_ADDR addr = memaddr & -(CORE_ADDR) sizeof (PTRACE_XFER_TYPE); /* Round ending address up; get number of longwords that makes. */ register int count = (((memaddr + len) - addr) + sizeof (PTRACE_XFER_TYPE) - 1) / sizeof (PTRACE_XFER_TYPE); /* Allocate buffer of that many longwords. */ register PTRACE_XFER_TYPE *buffer = (PTRACE_XFER_TYPE *) alloca (count * sizeof (PTRACE_XFER_TYPE)); int pid = lwpid_of (get_thread_lwp (current_inferior)); if (debug_threads) { /* Dump up to four bytes. */ unsigned int val = * (unsigned int *) myaddr; if (len == 1) val = val & 0xff; else if (len == 2) val = val & 0xffff; else if (len == 3) val = val & 0xffffff; fprintf (stderr, "Writing %0*x to 0x%08lx\n", 2 * ((len < 4) ? len : 4), val, (long)memaddr); } /* Fill start and end extra bytes of buffer with existing memory data. */ errno = 0; /* Coerce the 3rd arg to a uintptr_t first to avoid potential gcc warning about coercing an 8 byte integer to a 4 byte pointer. */ buffer[0] = ptrace (PTRACE_PEEKTEXT, pid, (PTRACE_ARG3_TYPE) (uintptr_t) addr, 0); if (errno) return errno; if (count > 1) { errno = 0; buffer[count - 1] = ptrace (PTRACE_PEEKTEXT, pid, /* Coerce to a uintptr_t first to avoid potential gcc warning about coercing an 8 byte integer to a 4 byte pointer. */ (PTRACE_ARG3_TYPE) (uintptr_t) (addr + (count - 1) * sizeof (PTRACE_XFER_TYPE)), 0); if (errno) return errno; } /* Copy data to be written over corresponding part of buffer. */ memcpy ((char *) buffer + (memaddr & (sizeof (PTRACE_XFER_TYPE) - 1)), myaddr, len); /* Write the entire buffer. */ for (i = 0; i < count; i++, addr += sizeof (PTRACE_XFER_TYPE)) { errno = 0; ptrace (PTRACE_POKETEXT, pid, /* Coerce to a uintptr_t first to avoid potential gcc warning about coercing an 8 byte integer to a 4 byte pointer. */ (PTRACE_ARG3_TYPE) (uintptr_t) addr, (PTRACE_ARG4_TYPE) buffer[i]); if (errno) return errno; } return 0; } /* Non-zero if the kernel supports PTRACE_O_TRACEFORK. */ static int linux_supports_tracefork_flag; static void linux_enable_event_reporting (int pid) { if (!linux_supports_tracefork_flag) return; ptrace (PTRACE_SETOPTIONS, pid, 0, (PTRACE_ARG4_TYPE) PTRACE_O_TRACECLONE); } /* Helper functions for linux_test_for_tracefork, called via clone (). */ static int linux_tracefork_grandchild (void *arg) { _exit (0); } #define STACK_SIZE 4096 static int linux_tracefork_child (void *arg) { ptrace (PTRACE_TRACEME, 0, 0, 0); kill (getpid (), SIGSTOP); #if !(defined(__UCLIBC__) && defined(HAS_NOMMU)) if (fork () == 0) linux_tracefork_grandchild (NULL); #else /* defined(__UCLIBC__) && defined(HAS_NOMMU) */ #ifdef __ia64__ __clone2 (linux_tracefork_grandchild, arg, STACK_SIZE, CLONE_VM | SIGCHLD, NULL); #else clone (linux_tracefork_grandchild, arg + STACK_SIZE, CLONE_VM | SIGCHLD, NULL); #endif #endif /* defined(__UCLIBC__) && defined(HAS_NOMMU) */ _exit (0); } /* Determine if PTRACE_O_TRACEFORK can be used to follow fork events. Make sure that we can enable the option, and that it had the desired effect. */ static void linux_test_for_tracefork (void) { int child_pid, ret, status; long second_pid; #if defined(__UCLIBC__) && defined(HAS_NOMMU) char *stack = xmalloc (STACK_SIZE * 4); #endif /* defined(__UCLIBC__) && defined(HAS_NOMMU) */ linux_supports_tracefork_flag = 0; #if !(defined(__UCLIBC__) && defined(HAS_NOMMU)) child_pid = fork (); if (child_pid == 0) linux_tracefork_child (NULL); #else /* defined(__UCLIBC__) && defined(HAS_NOMMU) */ /* Use CLONE_VM instead of fork, to support uClinux (no MMU). */ #ifdef __ia64__ child_pid = __clone2 (linux_tracefork_child, stack, STACK_SIZE, CLONE_VM | SIGCHLD, stack + STACK_SIZE * 2); #else /* !__ia64__ */ child_pid = clone (linux_tracefork_child, stack + STACK_SIZE, CLONE_VM | SIGCHLD, stack + STACK_SIZE * 2); #endif /* !__ia64__ */ #endif /* defined(__UCLIBC__) && defined(HAS_NOMMU) */ if (child_pid == -1) perror_with_name ("clone"); ret = my_waitpid (child_pid, &status, 0); if (ret == -1) perror_with_name ("waitpid"); else if (ret != child_pid) error ("linux_test_for_tracefork: waitpid: unexpected result %d.", ret); if (! WIFSTOPPED (status)) error ("linux_test_for_tracefork: waitpid: unexpected status %d.", status); ret = ptrace (PTRACE_SETOPTIONS, child_pid, 0, (PTRACE_ARG4_TYPE) PTRACE_O_TRACEFORK); if (ret != 0) { ret = ptrace (PTRACE_KILL, child_pid, 0, 0); if (ret != 0) { warning ("linux_test_for_tracefork: failed to kill child"); return; } ret = my_waitpid (child_pid, &status, 0); if (ret != child_pid) warning ("linux_test_for_tracefork: failed to wait for killed child"); else if (!WIFSIGNALED (status)) warning ("linux_test_for_tracefork: unexpected wait status 0x%x from " "killed child", status); return; } ret = ptrace (PTRACE_CONT, child_pid, 0, 0); if (ret != 0) warning ("linux_test_for_tracefork: failed to resume child"); ret = my_waitpid (child_pid, &status, 0); if (ret == child_pid && WIFSTOPPED (status) && status >> 16 == PTRACE_EVENT_FORK) { second_pid = 0; ret = ptrace (PTRACE_GETEVENTMSG, child_pid, 0, &second_pid); if (ret == 0 && second_pid != 0) { int second_status; linux_supports_tracefork_flag = 1; my_waitpid (second_pid, &second_status, 0); ret = ptrace (PTRACE_KILL, second_pid, 0, 0); if (ret != 0) warning ("linux_test_for_tracefork: failed to kill second child"); my_waitpid (second_pid, &status, 0); } } else warning ("linux_test_for_tracefork: unexpected result from waitpid " "(%d, status 0x%x)", ret, status); do { ret = ptrace (PTRACE_KILL, child_pid, 0, 0); if (ret != 0) warning ("linux_test_for_tracefork: failed to kill child"); my_waitpid (child_pid, &status, 0); } while (WIFSTOPPED (status)); #if defined(__UCLIBC__) && defined(HAS_NOMMU) free (stack); #endif /* defined(__UCLIBC__) && defined(HAS_NOMMU) */ } static void linux_look_up_symbols (void) { #ifdef USE_THREAD_DB struct process_info *proc = current_process (); if (proc->private->thread_db != NULL) return; /* If the kernel supports tracing forks then it also supports tracing clones, and then we don't need to use the magic thread event breakpoint to learn about threads. */ thread_db_init (!linux_supports_tracefork_flag); #endif } static void linux_request_interrupt (void) { extern unsigned long signal_pid; if (!ptid_equal (cont_thread, null_ptid) && !ptid_equal (cont_thread, minus_one_ptid)) { struct lwp_info *lwp; int lwpid; lwp = get_thread_lwp (current_inferior); lwpid = lwpid_of (lwp); kill_lwp (lwpid, SIGINT); } else kill_lwp (signal_pid, SIGINT); } /* Copy LEN bytes from inferior's auxiliary vector starting at OFFSET to debugger memory starting at MYADDR. */ static int linux_read_auxv (CORE_ADDR offset, unsigned char *myaddr, unsigned int len) { char filename[PATH_MAX]; int fd, n; int pid = lwpid_of (get_thread_lwp (current_inferior)); snprintf (filename, sizeof filename, "/proc/%d/auxv", pid); fd = open (filename, O_RDONLY); if (fd < 0) return -1; if (offset != (CORE_ADDR) 0 && lseek (fd, (off_t) offset, SEEK_SET) != (off_t) offset) n = -1; else n = read (fd, myaddr, len); close (fd); return n; } /* These breakpoint and watchpoint related wrapper functions simply pass on the function call if the target has registered a corresponding function. */ static int linux_insert_point (char type, CORE_ADDR addr, int len) { if (the_low_target.insert_point != NULL) return the_low_target.insert_point (type, addr, len); else /* Unsupported (see target.h). */ return 1; } static int linux_remove_point (char type, CORE_ADDR addr, int len) { if (the_low_target.remove_point != NULL) return the_low_target.remove_point (type, addr, len); else /* Unsupported (see target.h). */ return 1; } static int linux_stopped_by_watchpoint (void) { struct lwp_info *lwp = get_thread_lwp (current_inferior); return lwp->stopped_by_watchpoint; } static CORE_ADDR linux_stopped_data_address (void) { struct lwp_info *lwp = get_thread_lwp (current_inferior); return lwp->stopped_data_address; } #if defined(__UCLIBC__) && defined(HAS_NOMMU) #if defined(__mcoldfire__) /* These should really be defined in the kernel's ptrace.h header. */ #define PT_TEXT_ADDR 49*4 #define PT_DATA_ADDR 50*4 #define PT_TEXT_END_ADDR 51*4 #endif /* Under uClinux, programs are loaded at non-zero offsets, which we need to tell gdb about. */ static int linux_read_offsets (CORE_ADDR *text_p, CORE_ADDR *data_p) { #if defined(PT_TEXT_ADDR) && defined(PT_DATA_ADDR) && defined(PT_TEXT_END_ADDR) unsigned long text, text_end, data; int pid = lwpid_of (get_thread_lwp (current_inferior)); errno = 0; text = ptrace (PTRACE_PEEKUSER, pid, (long)PT_TEXT_ADDR, 0); text_end = ptrace (PTRACE_PEEKUSER, pid, (long)PT_TEXT_END_ADDR, 0); data = ptrace (PTRACE_PEEKUSER, pid, (long)PT_DATA_ADDR, 0); if (errno == 0) { /* Both text and data offsets produced at compile-time (and so used by gdb) are relative to the beginning of the program, with the data segment immediately following the text segment. However, the actual runtime layout in memory may put the data somewhere else, so when we send gdb a data base-address, we use the real data base address and subtract the compile-time data base-address from it (which is just the length of the text segment). BSS immediately follows data in both cases. */ *text_p = text; *data_p = data - (text_end - text); return 1; } #endif return 0; } #endif static int compare_ints (const void *xa, const void *xb) { int a = *(const int *)xa; int b = *(const int *)xb; return a - b; } static int * unique (int *b, int *e) { int *d = b; while (++b != e) if (*d != *b) *++d = *b; return ++d; } /* Given PID, iterates over all threads in that process. Information about each thread, in a format suitable for qXfer:osdata:thread is printed to BUFFER, if it's not NULL. BUFFER is assumed to be already initialized, and the caller is responsible for finishing and appending '\0' to it. The list of cores that threads are running on is assigned to *CORES, if it is not NULL. If no cores are found, *CORES will be set to NULL. Caller should free *CORES. */ static void list_threads (int pid, struct buffer *buffer, char **cores) { int count = 0; int allocated = 10; int *core_numbers = xmalloc (sizeof (int) * allocated); char pathname[128]; DIR *dir; struct dirent *dp; struct stat statbuf; sprintf (pathname, "/proc/%d/task", pid); if (stat (pathname, &statbuf) == 0 && S_ISDIR (statbuf.st_mode)) { dir = opendir (pathname); if (!dir) { free (core_numbers); return; } while ((dp = readdir (dir)) != NULL) { unsigned long lwp = strtoul (dp->d_name, NULL, 10); if (lwp != 0) { unsigned core = linux_core_of_thread (ptid_build (pid, lwp, 0)); if (core != -1) { char s[sizeof ("4294967295")]; sprintf (s, "%u", core); if (count == allocated) { allocated *= 2; core_numbers = realloc (core_numbers, sizeof (int) * allocated); } core_numbers[count++] = core; if (buffer) buffer_xml_printf (buffer, "<item>" "<column name=\"pid\">%d</column>" "<column name=\"tid\">%s</column>" "<column name=\"core\">%s</column>" "</item>", pid, dp->d_name, s); } else { if (buffer) buffer_xml_printf (buffer, "<item>" "<column name=\"pid\">%d</column>" "<column name=\"tid\">%s</column>" "</item>", pid, dp->d_name); } } } } if (cores) { *cores = NULL; if (count > 0) { struct buffer buffer2; int *b; int *e; qsort (core_numbers, count, sizeof (int), compare_ints); /* Remove duplicates. */ b = core_numbers; e = unique (b, core_numbers + count); buffer_init (&buffer2); for (b = core_numbers; b != e; ++b) { char number[sizeof ("4294967295")]; sprintf (number, "%u", *b); buffer_xml_printf (&buffer2, "%s%s", (b == core_numbers) ? "" : ",", number); } buffer_grow_str0 (&buffer2, ""); *cores = buffer_finish (&buffer2); } } free (core_numbers); } static void show_process (int pid, const char *username, struct buffer *buffer) { char pathname[128]; FILE *f; char cmd[MAXPATHLEN + 1]; sprintf (pathname, "/proc/%d/cmdline", pid); if ((f = fopen (pathname, "r")) != NULL) { size_t len = fread (cmd, 1, sizeof (cmd) - 1, f); if (len > 0) { char *cores = 0; int i; for (i = 0; i < len; i++) if (cmd[i] == '\0') cmd[i] = ' '; cmd[len] = '\0'; buffer_xml_printf (buffer, "<item>" "<column name=\"pid\">%d</column>" "<column name=\"user\">%s</column>" "<column name=\"command\">%s</column>", pid, username, cmd); /* This only collects core numbers, and does not print threads. */ list_threads (pid, NULL, &cores); if (cores) { buffer_xml_printf (buffer, "<column name=\"cores\">%s</column>", cores); free (cores); } buffer_xml_printf (buffer, "</item>"); } fclose (f); } } static int linux_qxfer_osdata (const char *annex, unsigned char *readbuf, unsigned const char *writebuf, CORE_ADDR offset, int len) { /* We make the process list snapshot when the object starts to be read. */ static const char *buf; static long len_avail = -1; static struct buffer buffer; int processes = 0; int threads = 0; DIR *dirp; if (strcmp (annex, "processes") == 0) processes = 1; else if (strcmp (annex, "threads") == 0) threads = 1; else return 0; if (!readbuf || writebuf) return 0; if (offset == 0) { if (len_avail != -1 && len_avail != 0) buffer_free (&buffer); len_avail = 0; buf = NULL; buffer_init (&buffer); if (processes) buffer_grow_str (&buffer, "<osdata type=\"processes\">"); else if (threads) buffer_grow_str (&buffer, "<osdata type=\"threads\">"); dirp = opendir ("/proc"); if (dirp) { struct dirent *dp; while ((dp = readdir (dirp)) != NULL) { struct stat statbuf; char procentry[sizeof ("/proc/4294967295")]; if (!isdigit (dp->d_name[0]) || strlen (dp->d_name) > sizeof ("4294967295") - 1) continue; sprintf (procentry, "/proc/%s", dp->d_name); if (stat (procentry, &statbuf) == 0 && S_ISDIR (statbuf.st_mode)) { int pid = (int) strtoul (dp->d_name, NULL, 10); if (processes) { struct passwd *entry = getpwuid (statbuf.st_uid); show_process (pid, entry ? entry->pw_name : "?", &buffer); } else if (threads) { list_threads (pid, &buffer, NULL); } } } closedir (dirp); } buffer_grow_str0 (&buffer, "</osdata>\n"); buf = buffer_finish (&buffer); len_avail = strlen (buf); } if (offset >= len_avail) { /* Done. Get rid of the data. */ buffer_free (&buffer); buf = NULL; len_avail = 0; return 0; } if (len > len_avail - offset) len = len_avail - offset; memcpy (readbuf, buf + offset, len); return len; } /* Convert a native/host siginfo object, into/from the siginfo in the layout of the inferiors' architecture. */ static void siginfo_fixup (struct siginfo *siginfo, void *inf_siginfo, int direction) { int done = 0; if (the_low_target.siginfo_fixup != NULL) done = the_low_target.siginfo_fixup (siginfo, inf_siginfo, direction); /* If there was no callback, or the callback didn't do anything, then just do a straight memcpy. */ if (!done) { if (direction == 1) memcpy (siginfo, inf_siginfo, sizeof (struct siginfo)); else memcpy (inf_siginfo, siginfo, sizeof (struct siginfo)); } } static int linux_xfer_siginfo (const char *annex, unsigned char *readbuf, unsigned const char *writebuf, CORE_ADDR offset, int len) { int pid; struct siginfo siginfo; char inf_siginfo[sizeof (struct siginfo)]; if (current_inferior == NULL) return -1; pid = lwpid_of (get_thread_lwp (current_inferior)); if (debug_threads) fprintf (stderr, "%s siginfo for lwp %d.\n", readbuf != NULL ? "Reading" : "Writing", pid); if (offset > sizeof (siginfo)) return -1; if (ptrace (PTRACE_GETSIGINFO, pid, 0, &siginfo) != 0) return -1; /* When GDBSERVER is built as a 64-bit application, ptrace writes into SIGINFO an object with 64-bit layout. Since debugging a 32-bit inferior with a 64-bit GDBSERVER should look the same as debugging it with a 32-bit GDBSERVER, we need to convert it. */ siginfo_fixup (&siginfo, inf_siginfo, 0); if (offset + len > sizeof (siginfo)) len = sizeof (siginfo) - offset; if (readbuf != NULL) memcpy (readbuf, inf_siginfo + offset, len); else { memcpy (inf_siginfo + offset, writebuf, len); /* Convert back to ptrace layout before flushing it out. */ siginfo_fixup (&siginfo, inf_siginfo, 1); if (ptrace (PTRACE_SETSIGINFO, pid, 0, &siginfo) != 0) return -1; } return len; } /* SIGCHLD handler that serves two purposes: In non-stop/async mode, so we notice when children change state; as the handler for the sigsuspend in my_waitpid. */ static void sigchld_handler (int signo) { int old_errno = errno; if (debug_threads) /* fprintf is not async-signal-safe, so call write directly. */ write (2, "sigchld_handler\n", sizeof ("sigchld_handler\n") - 1); if (target_is_async_p ()) async_file_mark (); /* trigger a linux_wait */ errno = old_errno; } static int linux_supports_non_stop (void) { return 1; } static int linux_async (int enable) { int previous = (linux_event_pipe[0] != -1); if (debug_threads) fprintf (stderr, "linux_async (%d), previous=%d\n", enable, previous); if (previous != enable) { sigset_t mask; sigemptyset (&mask); sigaddset (&mask, SIGCHLD); sigprocmask (SIG_BLOCK, &mask, NULL); if (enable) { if (pipe (linux_event_pipe) == -1) fatal ("creating event pipe failed."); fcntl (linux_event_pipe[0], F_SETFL, O_NONBLOCK); fcntl (linux_event_pipe[1], F_SETFL, O_NONBLOCK); /* Register the event loop handler. */ add_file_handler (linux_event_pipe[0], handle_target_event, NULL); /* Always trigger a linux_wait. */ async_file_mark (); } else { delete_file_handler (linux_event_pipe[0]); close (linux_event_pipe[0]); close (linux_event_pipe[1]); linux_event_pipe[0] = -1; linux_event_pipe[1] = -1; } sigprocmask (SIG_UNBLOCK, &mask, NULL); } return previous; } static int linux_start_non_stop (int nonstop) { /* Register or unregister from event-loop accordingly. */ linux_async (nonstop); return 0; } static int linux_supports_multi_process (void) { return 1; } /* Enumerate spufs IDs for process PID. */ static int spu_enumerate_spu_ids (long pid, unsigned char *buf, CORE_ADDR offset, int len) { int pos = 0; int written = 0; char path[128]; DIR *dir; struct dirent *entry; sprintf (path, "/proc/%ld/fd", pid); dir = opendir (path); if (!dir) return -1; rewinddir (dir); while ((entry = readdir (dir)) != NULL) { struct stat st; struct statfs stfs; int fd; fd = atoi (entry->d_name); if (!fd) continue; sprintf (path, "/proc/%ld/fd/%d", pid, fd); if (stat (path, &st) != 0) continue; if (!S_ISDIR (st.st_mode)) continue; if (statfs (path, &stfs) != 0) continue; if (stfs.f_type != SPUFS_MAGIC) continue; if (pos >= offset && pos + 4 <= offset + len) { *(unsigned int *)(buf + pos - offset) = fd; written += 4; } pos += 4; } closedir (dir); return written; } /* Implements the to_xfer_partial interface for the TARGET_OBJECT_SPU object type, using the /proc file system. */ static int linux_qxfer_spu (const char *annex, unsigned char *readbuf, unsigned const char *writebuf, CORE_ADDR offset, int len) { long pid = lwpid_of (get_thread_lwp (current_inferior)); char buf[128]; int fd = 0; int ret = 0; if (!writebuf && !readbuf) return -1; if (!*annex) { if (!readbuf) return -1; else return spu_enumerate_spu_ids (pid, readbuf, offset, len); } sprintf (buf, "/proc/%ld/fd/%s", pid, annex); fd = open (buf, writebuf? O_WRONLY : O_RDONLY); if (fd <= 0) return -1; if (offset != 0 && lseek (fd, (off_t) offset, SEEK_SET) != (off_t) offset) { close (fd); return 0; } if (writebuf) ret = write (fd, writebuf, (size_t) len); else ret = read (fd, readbuf, (size_t) len); close (fd); return ret; } static int linux_core_of_thread (ptid_t ptid) { char filename[sizeof ("/proc//task//stat") + 2 * 20 /* decimal digits for 2 numbers, max 2^64 bit each */ + 1]; FILE *f; char *content = NULL; char *p; char *ts = 0; int content_read = 0; int i; int core; sprintf (filename, "/proc/%d/task/%ld/stat", ptid_get_pid (ptid), ptid_get_lwp (ptid)); f = fopen (filename, "r"); if (!f) return -1; for (;;) { int n; content = realloc (content, content_read + 1024); n = fread (content + content_read, 1, 1024, f); content_read += n; if (n < 1024) { content[content_read] = '\0'; break; } } p = strchr (content, '('); /* Skip ")". */ if (p != NULL) p = strchr (p, ')'); if (p != NULL) p++; /* If the first field after program name has index 0, then core number is the field with index 36. There's no constant for that anywhere. */ if (p != NULL) p = strtok_r (p, " ", &ts); for (i = 0; p != NULL && i != 36; ++i) p = strtok_r (NULL, " ", &ts); if (p == NULL || sscanf (p, "%d", &core) == 0) core = -1; free (content); fclose (f); return core; } static void linux_process_qsupported (const char *query) { if (the_low_target.process_qsupported != NULL) the_low_target.process_qsupported (query); } static int linux_supports_tracepoints (void) { if (*the_low_target.supports_tracepoints == NULL) return 0; return (*the_low_target.supports_tracepoints) (); } static CORE_ADDR linux_read_pc (struct regcache *regcache) { if (the_low_target.get_pc == NULL) return 0; return (*the_low_target.get_pc) (regcache); } static void linux_write_pc (struct regcache *regcache, CORE_ADDR pc) { gdb_assert (the_low_target.set_pc != NULL); (*the_low_target.set_pc) (regcache, pc); } static int linux_thread_stopped (struct thread_info *thread) { return get_thread_lwp (thread)->stopped; } /* This exposes stop-all-threads functionality to other modules. */ static void linux_pause_all (int freeze) { stop_all_lwps (freeze, NULL); } /* This exposes unstop-all-threads functionality to other gdbserver modules. */ static void linux_unpause_all (int unfreeze) { unstop_all_lwps (unfreeze, NULL); } static int linux_install_fast_tracepoint_jump_pad (CORE_ADDR tpoint, CORE_ADDR tpaddr, CORE_ADDR collector, CORE_ADDR lockaddr, ULONGEST orig_size, CORE_ADDR *jump_entry, unsigned char *jjump_pad_insn, ULONGEST *jjump_pad_insn_size, CORE_ADDR *adjusted_insn_addr, CORE_ADDR *adjusted_insn_addr_end) { return (*the_low_target.install_fast_tracepoint_jump_pad) (tpoint, tpaddr, collector, lockaddr, orig_size, jump_entry, jjump_pad_insn, jjump_pad_insn_size, adjusted_insn_addr, adjusted_insn_addr_end); } static struct emit_ops * linux_emit_ops (void) { if (the_low_target.emit_ops != NULL) return (*the_low_target.emit_ops) (); else return NULL; } static struct target_ops linux_target_ops = { linux_create_inferior, linux_attach, linux_kill, linux_detach, linux_mourn, linux_join, linux_thread_alive, linux_resume, linux_wait, linux_fetch_registers, linux_store_registers, linux_read_memory, linux_write_memory, linux_look_up_symbols, linux_request_interrupt, linux_read_auxv, linux_insert_point, linux_remove_point, linux_stopped_by_watchpoint, linux_stopped_data_address, #if defined(__UCLIBC__) && defined(HAS_NOMMU) linux_read_offsets, #else NULL, #endif #ifdef USE_THREAD_DB thread_db_get_tls_address, #else NULL, #endif linux_qxfer_spu, hostio_last_error_from_errno, linux_qxfer_osdata, linux_xfer_siginfo, linux_supports_non_stop, linux_async, linux_start_non_stop, linux_supports_multi_process, #ifdef USE_THREAD_DB thread_db_handle_monitor_command, #else NULL, #endif linux_core_of_thread, linux_process_qsupported, linux_supports_tracepoints, linux_read_pc, linux_write_pc, linux_thread_stopped, NULL, linux_pause_all, linux_unpause_all, linux_cancel_breakpoints, linux_stabilize_threads, linux_install_fast_tracepoint_jump_pad, linux_emit_ops }; static void linux_init_signals () { /* FIXME drow/2002-06-09: As above, we should check with LinuxThreads to find what the cancel signal actually is. */ #ifdef __SIGRTMIN /* Bionic doesn't use SIGRTMIN the way glibc does. */ signal (__SIGRTMIN+1, SIG_IGN); #endif } void initialize_low (void) { struct sigaction sigchld_action; memset (&sigchld_action, 0, sizeof (sigchld_action)); set_target_ops (&linux_target_ops); set_breakpoint_data (the_low_target.breakpoint, the_low_target.breakpoint_len); linux_init_signals (); linux_test_for_tracefork (); #ifdef HAVE_LINUX_REGSETS for (num_regsets = 0; target_regsets[num_regsets].size >= 0; num_regsets++) ; disabled_regsets = xmalloc (num_regsets); #endif sigchld_action.sa_handler = sigchld_handler; sigemptyset (&sigchld_action.sa_mask); sigchld_action.sa_flags = SA_RESTART; sigaction (SIGCHLD, &sigchld_action, NULL); }
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