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/* Core dump and executable file functions below target vector, for GDB.

   Copyright (C) 1986, 1987, 1989, 1991, 1992, 1993, 1994, 1995, 1996, 1997,

   1998, 1999, 2000, 2001, 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 "defs.h"

#include "arch-utils.h"

#include "gdb_string.h"

#include <errno.h>

#include <signal.h>

#include <fcntl.h>

#ifdef HAVE_SYS_FILE_H

#include <sys/file.h>           /* needed for F_OK and friends */

#endif

#include "frame.h"              /* required by inferior.h */

#include "inferior.h"

#include "symtab.h"

#include "command.h"

#include "bfd.h"

#include "target.h"

#include "gdbcore.h"

#include "gdbthread.h"

#include "regcache.h"

#include "regset.h"

#include "symfile.h"

#include "exec.h"

#include "readline/readline.h"

#include "gdb_assert.h"

#include "exceptions.h"

#include "solib.h"

#include "filenames.h"

#include "progspace.h"

#ifndef O_LARGEFILE

#define O_LARGEFILE 0

#endif

/* List of all available core_fns.  On gdb startup, each core file

   register reader calls deprecated_add_core_fns() to register

   information on each core format it is prepared to read.  */

static struct core_fns *core_file_fns = NULL;

/* The core_fns for a core file handler that is prepared to read the core

   file currently open on core_bfd. */

static struct core_fns *core_vec = NULL;

/* FIXME: kettenis/20031023: Eventually this variable should

   disappear.  */

struct gdbarch *core_gdbarch = NULL;

/* Per-core data.  Currently, only the section table.  Note that these

   target sections are *not* mapped in the current address spaces' set

   of target sections --- those should come only from pure executable

   or shared library bfds.  The core bfd sections are an

   implementation detail of the core target, just like ptrace is for

   unix child targets.  */

static struct target_section_table *core_data;

/* True if we needed to fake the pid of the loaded core inferior.  */

static int core_has_fake_pid = 0;

static void core_files_info (struct target_ops *);

static struct core_fns *sniff_core_bfd (bfd *);

static int gdb_check_format (bfd *);

static void core_open (char *, int);

static void core_detach (struct target_ops *ops, char *, int);

static void core_close (int);

static void core_close_cleanup (void *ignore);

static void add_to_thread_list (bfd *, asection *, void *);

static void init_core_ops (void);

void _initialize_corelow (void);

struct target_ops core_ops;

/* An arbitrary identifier for the core inferior.  */

#define CORELOW_PID 1

/* Link a new core_fns into the global core_file_fns list.  Called on gdb

   startup by the _initialize routine in each core file register reader, to

   register information about each format the the reader is prepared to

   handle. */

void

deprecated_add_core_fns (struct core_fns *cf)

{

  cf->next = core_file_fns;

  core_file_fns = cf;

}

/* The default function that core file handlers can use to examine a

   core file BFD and decide whether or not to accept the job of

   reading the core file. */

int

default_core_sniffer (struct core_fns *our_fns, bfd *abfd)

{

  int result;

  result = (bfd_get_flavour (abfd) == our_fns -> core_flavour);

  return (result);

}

/* Walk through the list of core functions to find a set that can

   handle the core file open on ABFD.  Default to the first one in the

   list if nothing matches.  Returns pointer to set that is

   selected. */

static struct core_fns *

sniff_core_bfd (bfd *abfd)

{

  struct core_fns *cf;

  struct core_fns *yummy = NULL;

  int matches = 0;;

  /* Don't sniff if we have support for register sets in CORE_GDBARCH.  */

  if (core_gdbarch && gdbarch_regset_from_core_section_p (core_gdbarch))

    return NULL;

  for (cf = core_file_fns; cf != NULL; cf = cf->next)

    {

      if (cf->core_sniffer (cf, abfd))

        {

          yummy = cf;

          matches++;

        }

    }

  if (matches > 1)

    {

      warning (_("\"%s\": ambiguous core format, %d handlers match"),

               bfd_get_filename (abfd), matches);

    }

  else if (matches == 0)

    {

      warning (_("\"%s\": no core file handler recognizes format, using default"),

               bfd_get_filename (abfd));

    }

  if (yummy == NULL)

    {

      yummy = core_file_fns;

    }

  return (yummy);

}

/* The default is to reject every core file format we see.  Either

   BFD has to recognize it, or we have to provide a function in the

   core file handler that recognizes it. */

int

default_check_format (bfd *abfd)

{

  return (0);

}

/* Attempt to recognize core file formats that BFD rejects. */

static int

gdb_check_format (bfd *abfd)

{

  struct core_fns *cf;

  for (cf = core_file_fns; cf != NULL; cf = cf->next)

    {

      if (cf->check_format (abfd))

        {

          return (1);

        }

    }

  return (0);

}

/* Discard all vestiges of any previous core file and mark data and stack

   spaces as empty.  */

static void

core_close (int quitting)

{

  char *name;

  if (core_bfd)

    {

      int pid = ptid_get_pid (inferior_ptid);

      inferior_ptid = null_ptid;        /* Avoid confusion from thread stuff */

      exit_inferior_silent (pid);

      /* Clear out solib state while the bfd is still open. See

         comments in clear_solib in solib.c. */

      clear_solib ();

      xfree (core_data->sections);

      xfree (core_data);

      core_data = NULL;

      core_has_fake_pid = 0;

      name = bfd_get_filename (core_bfd);

      if (!bfd_close (core_bfd))

        warning (_("cannot close \"%s\": %s"),

                 name, bfd_errmsg (bfd_get_error ()));

      xfree (name);

      core_bfd = NULL;

    }

  core_vec = NULL;

  core_gdbarch = NULL;

}

static void

core_close_cleanup (void *ignore)

{

  core_close (0/*ignored*/);

}

/* Look for sections whose names start with `.reg/' so that we can extract the

   list of threads in a core file.  */

static void

add_to_thread_list (bfd *abfd, asection *asect, void *reg_sect_arg)

{

  ptid_t ptid;

  int core_tid;

  int pid, lwpid;

  asection *reg_sect = (asection *) reg_sect_arg;

  if (strncmp (bfd_section_name (abfd, asect), ".reg/", 5) != 0)

    return;

  core_tid = atoi (bfd_section_name (abfd, asect) + 5);

  if (core_gdbarch

      && gdbarch_core_reg_section_encodes_pid (core_gdbarch))

    {

      uint32_t merged_pid = core_tid;

      pid = merged_pid & 0xffff;

      lwpid = merged_pid >> 16;

      /* This can happen on solaris core, for example, if we don't

         find a NT_PSTATUS note in the core, but do find NT_LWPSTATUS

         notes.  */

      if (pid == 0)

        {

          core_has_fake_pid = 1;

          pid = CORELOW_PID;

        }

    }

  else

    {

      core_has_fake_pid = 1;

      pid = CORELOW_PID;

      lwpid = core_tid;

    }

  if (current_inferior ()->pid == 0)

    inferior_appeared (current_inferior (), pid);

  ptid = ptid_build (pid, lwpid, 0);

  add_thread (ptid);

/* Warning, Will Robinson, looking at BFD private data! */

  if (reg_sect != NULL

      && asect->filepos == reg_sect->filepos)   /* Did we find .reg? */

    inferior_ptid = ptid;                        /* Yes, make it current */

}

/* This routine opens and sets up the core file bfd.  */

static void

core_open (char *filename, int from_tty)

{

  const char *p;

  int siggy;

  struct cleanup *old_chain;

  char *temp;

  bfd *temp_bfd;

  int scratch_chan;

  int flags;

  target_preopen (from_tty);

  if (!filename)

    {

      if (core_bfd)

        error (_("No core file specified.  (Use `detach' to stop debugging a core file.)"));

      else

        error (_("No core file specified."));

    }

  filename = tilde_expand (filename);

  if (!IS_ABSOLUTE_PATH(filename))

    {

      temp = concat (current_directory, "/", filename, (char *)NULL);

      xfree (filename);

      filename = temp;

    }

  old_chain = make_cleanup (xfree, filename);

  flags = O_BINARY | O_LARGEFILE;

  if (write_files)

    flags |= O_RDWR;

  else

    flags |= O_RDONLY;

  scratch_chan = open (filename, flags, 0);

  if (scratch_chan < 0)

    perror_with_name (filename);

  temp_bfd = bfd_fopen (filename, gnutarget,

                        write_files ? FOPEN_RUB : FOPEN_RB,

                        scratch_chan);

  if (temp_bfd == NULL)

    perror_with_name (filename);

  if (!bfd_check_format (temp_bfd, bfd_core)

      && !gdb_check_format (temp_bfd))

    {

      /* Do it after the err msg */

      /* FIXME: should be checking for errors from bfd_close (for one thing,

         on error it does not free all the storage associated with the

         bfd).  */

      make_cleanup_bfd_close (temp_bfd);

      error (_("\"%s\" is not a core dump: %s"),

             filename, bfd_errmsg (bfd_get_error ()));

    }

  /* Looks semi-reasonable.  Toss the old core file and work on the new.  */

  discard_cleanups (old_chain); /* Don't free filename any more */

  unpush_target (&core_ops);

  core_bfd = temp_bfd;

  old_chain = make_cleanup (core_close_cleanup, 0 /*ignore*/);

  /* FIXME: kettenis/20031023: This is very dangerous.  The

     CORE_GDBARCH that results from this call may very well be

     different from CURRENT_GDBARCH.  However, its methods may only

     work if it is selected as the current architecture, because they

     rely on swapped data (see gdbarch.c).  We should get rid of that

     swapped data.  */

  core_gdbarch = gdbarch_from_bfd (core_bfd);

  /* Find a suitable core file handler to munch on core_bfd */

  core_vec = sniff_core_bfd (core_bfd);

  validate_files ();

  core_data = XZALLOC (struct target_section_table);

  /* Find the data section */

  if (build_section_table (core_bfd,

                           &core_data->sections, &core_data->sections_end))

    error (_("\"%s\": Can't find sections: %s"),

           bfd_get_filename (core_bfd), bfd_errmsg (bfd_get_error ()));

  /* If we have no exec file, try to set the architecture from the

     core file.  We don't do this unconditionally since an exec file

     typically contains more information that helps us determine the

     architecture than a core file.  */

  if (!exec_bfd)

    set_gdbarch_from_file (core_bfd);

  push_target (&core_ops);

  discard_cleanups (old_chain);

  /* Do this before acknowledging the inferior, so if

     post_create_inferior throws (can happen easilly if you're loading

     a core file with the wrong exec), we aren't left with threads

     from the previous inferior.  */

  init_thread_list ();

  inferior_ptid = null_ptid;

  core_has_fake_pid = 0;

  /* Need to flush the register cache (and the frame cache) from a

     previous debug session.  If inferior_ptid ends up the same as the

     last debug session --- e.g., b foo; run; gcore core1; step; gcore

     core2; core core1; core core2 --- then there's potential for

     get_current_regcache to return the cached regcache of the

     previous session, and the frame cache being stale.  */

  registers_changed ();

  /* Build up thread list from BFD sections, and possibly set the

     current thread to the .reg/NN section matching the .reg

     section. */

  bfd_map_over_sections (core_bfd, add_to_thread_list,

                         bfd_get_section_by_name (core_bfd, ".reg"));

  if (ptid_equal (inferior_ptid, null_ptid))

    {

      /* Either we found no .reg/NN section, and hence we have a

         non-threaded core (single-threaded, from gdb's perspective),

         or for some reason add_to_thread_list couldn't determine

         which was the "main" thread.  The latter case shouldn't

         usually happen, but we're dealing with input here, which can

         always be broken in different ways.  */

      struct thread_info *thread = first_thread_of_process (-1);

      if (thread == NULL)

        {

          inferior_appeared (current_inferior (), CORELOW_PID);

          inferior_ptid = pid_to_ptid (CORELOW_PID);

          add_thread_silent (inferior_ptid);

        }

      else

        switch_to_thread (thread->ptid);

    }

  post_create_inferior (&core_ops, from_tty);

  /* Now go through the target stack looking for threads since there

     may be a thread_stratum target loaded on top of target core by

     now.  The layer above should claim threads found in the BFD

     sections.  */

  target_find_new_threads ();

  p = bfd_core_file_failing_command (core_bfd);

  if (p)

    printf_filtered (_("Core was generated by `%s'.\n"), p);

  siggy = bfd_core_file_failing_signal (core_bfd);

  if (siggy > 0)

    /* NOTE: target_signal_from_host() converts a target signal value

       into gdb's internal signal value.  Unfortunately gdb's internal

       value is called ``target_signal'' and this function got the

       name ..._from_host(). */

    printf_filtered (_("Program terminated with signal %d, %s.\n"), siggy,

                     target_signal_to_string (

                       (core_gdbarch != NULL) ?

                        gdbarch_target_signal_from_host (core_gdbarch, siggy)

                        : siggy));

  /* Fetch all registers from core file.  */

  target_fetch_registers (get_current_regcache (), -1);

  /* Now, set up the frame cache, and print the top of stack.  */

  reinit_frame_cache ();

  print_stack_frame (get_selected_frame (NULL), 1, SRC_AND_LOC);

}

static void

core_detach (struct target_ops *ops, char *args, int from_tty)

{

  if (args)

    error (_("Too many arguments"));

  unpush_target (ops);

  reinit_frame_cache ();

  if (from_tty)

    printf_filtered (_("No core file now.\n"));

}

#ifdef DEPRECATED_IBM6000_TARGET

/* Resize the core memory's section table, by NUM_ADDED.  Returns a

   pointer into the first new slot.  This will not be necessary when

   the rs6000 target is converted to use the standard solib

   framework.  */

struct target_section *

deprecated_core_resize_section_table (int num_added)

{

  int old_count;

  old_count = resize_section_table (core_data, num_added);

  return core_data->sections + old_count;

}

#endif

/* Try to retrieve registers from a section in core_bfd, and supply

   them to core_vec->core_read_registers, as the register set numbered

   WHICH.

   If inferior_ptid's lwp member is zero, do the single-threaded

   thing: look for a section named NAME.  If inferior_ptid's lwp

   member is non-zero, do the multi-threaded thing: look for a section

   named "NAME/LWP", where LWP is the shortest ASCII decimal

   representation of inferior_ptid's lwp member.

   HUMAN_NAME is a human-readable name for the kind of registers the

   NAME section contains, for use in error messages.

   If REQUIRED is non-zero, print an error if the core file doesn't

   have a section by the appropriate name.  Otherwise, just do nothing.  */

static void

get_core_register_section (struct regcache *regcache,

                           const char *name,

                           int which,

                           const char *human_name,

                           int required)

{

  static char *section_name = NULL;

  struct bfd_section *section;

  bfd_size_type size;

  char *contents;

  xfree (section_name);

  if (core_gdbarch

      && gdbarch_core_reg_section_encodes_pid (core_gdbarch))

    {

      uint32_t merged_pid;

      int pid = ptid_get_pid (inferior_ptid);

      if (core_has_fake_pid)

        pid = 0;

      merged_pid = ptid_get_lwp (inferior_ptid);

      merged_pid = merged_pid << 16 | pid;

      section_name = xstrprintf ("%s/%s", name, plongest (merged_pid));

    }

  else if (ptid_get_lwp (inferior_ptid))

    section_name = xstrprintf ("%s/%ld", name, ptid_get_lwp (inferior_ptid));

  else

    section_name = xstrdup (name);

  section = bfd_get_section_by_name (core_bfd, section_name);

  if (! section)

    {

      if (required)

        warning (_("Couldn't find %s registers in core file."), human_name);

      return;

    }

  size = bfd_section_size (core_bfd, section);

  contents = alloca (size);

  if (! bfd_get_section_contents (core_bfd, section, contents,

                                  (file_ptr) 0, size))

    {

      warning (_("Couldn't read %s registers from `%s' section in core file."),

               human_name, name);

      return;

    }

  if (core_gdbarch && gdbarch_regset_from_core_section_p (core_gdbarch))

    {

      const struct regset *regset;

      regset = gdbarch_regset_from_core_section (core_gdbarch, name, size);

      if (regset == NULL)

        {

          if (required)

            warning (_("Couldn't recognize %s registers in core file."),

                     human_name);

          return;

        }

      regset->supply_regset (regset, regcache, -1, contents, size);

      return;

    }

  gdb_assert (core_vec);

  core_vec->core_read_registers (regcache, contents, size, which,

                                 ((CORE_ADDR)

                                  bfd_section_vma (core_bfd, section)));

}

/* Get the registers out of a core file.  This is the machine-

   independent part.  Fetch_core_registers is the machine-dependent

   part, typically implemented in the xm-file for each architecture.  */

/* We just get all the registers, so we don't use regno.  */

static void

get_core_registers (struct target_ops *ops,

                    struct regcache *regcache, int regno)

{

  struct core_regset_section *sect_list;

  int i;

  if (!(core_gdbarch && gdbarch_regset_from_core_section_p (core_gdbarch))

      && (core_vec == NULL || core_vec->core_read_registers == NULL))

    {

      fprintf_filtered (gdb_stderr,

                     "Can't fetch registers from this type of core file\n");

      return;

    }

  sect_list = gdbarch_core_regset_sections (get_regcache_arch (regcache));

  if (sect_list)

    while (sect_list->sect_name != NULL)

      {

        if (strcmp (sect_list->sect_name, ".reg") == 0)

          get_core_register_section (regcache, sect_list->sect_name,

                                     0, sect_list->human_name, 1);

        else if (strcmp (sect_list->sect_name, ".reg2") == 0)

          get_core_register_section (regcache, sect_list->sect_name,

                                     2, sect_list->human_name, 0);

        else

          get_core_register_section (regcache, sect_list->sect_name,

                                     3, sect_list->human_name, 0);

        sect_list++;

      }

  else

    {

      get_core_register_section (regcache,

                                 ".reg", 0, "general-purpose", 1);

      get_core_register_section (regcache,

                                 ".reg2", 2, "floating-point", 0);

    }

  /* Supply dummy value for all registers not found in the core.  */

  for (i = 0; i < gdbarch_num_regs (get_regcache_arch (regcache)); i++)

    if (!regcache_valid_p (regcache, i))

      regcache_raw_supply (regcache, i, NULL);

}

static void

core_files_info (struct target_ops *t)

{

  print_section_info (core_data, core_bfd);

}

struct spuid_list

{

  gdb_byte *buf;

  ULONGEST offset;

  LONGEST len;

  ULONGEST pos;

  ULONGEST written;

};

static void

add_to_spuid_list (bfd *abfd, asection *asect, void *list_p)

{

  struct spuid_list *list = list_p;

  enum bfd_endian byte_order

    = bfd_big_endian (abfd)? BFD_ENDIAN_BIG : BFD_ENDIAN_LITTLE;

  int fd, pos = 0;

  sscanf (bfd_section_name (abfd, asect), "SPU/%d/regs%n", &fd, &pos);

  if (pos == 0)

    return;

  if (list->pos >= list->offset && list->pos + 4 <= list->offset + list->len)

    {

      store_unsigned_integer (list->buf + list->pos - list->offset,

                              4, byte_order, fd);

      list->written += 4;

    }

  list->pos += 4;

}

static LONGEST

core_xfer_partial (struct target_ops *ops, enum target_object object,

                   const char *annex, gdb_byte *readbuf,

                   const gdb_byte *writebuf, ULONGEST offset, LONGEST len)

{

  switch (object)

    {

    case TARGET_OBJECT_MEMORY:

      return section_table_xfer_memory_partial (readbuf, writebuf,

                                                offset, len,

                                                core_data->sections,

                                                core_data->sections_end,

                                                NULL);

    case TARGET_OBJECT_AUXV:

      if (readbuf)

        {

          /* When the aux vector is stored in core file, BFD

             represents this with a fake section called ".auxv".  */

          struct bfd_section *section;

          bfd_size_type size;

          char *contents;

          section = bfd_get_section_by_name (core_bfd, ".auxv");

          if (section == NULL)

            return -1;

          size = bfd_section_size (core_bfd, section);

          if (offset >= size)

            return 0;

          size -= offset;

          if (size > len)

            size = len;

          if (size > 0

              && !bfd_get_section_contents (core_bfd, section, readbuf,

                                            (file_ptr) offset, size))

            {

              warning (_("Couldn't read NT_AUXV note in core file."));