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/* Handle SunOS and SVR4 shared libraries for GDB, the GNU Debugger.

   Copyright 1990, 91, 92, 93, 94, 95, 96, 98, 1999

   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 2 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, write to the Free Software

   Foundation, Inc., 59 Temple Place - Suite 330,

   Boston, MA 02111-1307, USA.  */

#include "defs.h"

/* This file is only compilable if link.h is available. */

#ifdef HAVE_LINK_H

#include <sys/types.h>

#include <signal.h>

#include "gdb_string.h"

#include <sys/param.h>

#include <fcntl.h>

#ifndef SVR4_SHARED_LIBS

 /* SunOS shared libs need the nlist structure.  */

#include <a.out.h>

#else

#include "elf/external.h"

#endif

#include <link.h>

#include "symtab.h"

#include "bfd.h"

#include "symfile.h"

#include "objfiles.h"

#include "gdbcore.h"

#include "command.h"

#include "target.h"

#include "frame.h"

#include "gdb_regex.h"

#include "inferior.h"

#include "environ.h"

#include "language.h"

#include "gdbcmd.h"

#define MAX_PATH_SIZE 512       /* FIXME: Should be dynamic */

/* On SVR4 systems, a list of symbols in the dynamic linker where

   GDB can try to place a breakpoint to monitor shared library

   events.

   If none of these symbols are found, or other errors occur, then

   SVR4 systems will fall back to using a symbol as the "startup

   mapping complete" breakpoint address.  */

#ifdef SVR4_SHARED_LIBS

static char *solib_break_names[] =

{

  "r_debug_state",

  "_r_debug_state",

  "_dl_debug_state",

  "rtld_db_dlactivity",

  NULL

};

#endif

#define BKPT_AT_SYMBOL 1

#if defined (BKPT_AT_SYMBOL) && defined (SVR4_SHARED_LIBS)

static char *bkpt_names[] =

{

#ifdef SOLIB_BKPT_NAME

  SOLIB_BKPT_NAME,              /* Prefer configured name if it exists. */

#endif

  "_start",

  "main",

  NULL

};

#endif

/* Symbols which are used to locate the base of the link map structures. */

#ifndef SVR4_SHARED_LIBS

static char *debug_base_symbols[] =

{

  "_DYNAMIC",

  "_DYNAMIC__MGC",

  NULL

};

#endif

static char *main_name_list[] =

{

  "main_$main",

  NULL

};

/* local data declarations */

/* Macro to extract an address from a solib structure.

   When GDB is configured for some 32-bit targets (e.g. Solaris 2.7

   sparc), BFD is configured to handle 64-bit targets, so CORE_ADDR is

   64 bits.  We have to extract only the significant bits of addresses

   to get the right address when accessing the core file BFD.  */

#define SOLIB_EXTRACT_ADDRESS(member) \

  extract_address (&member, sizeof (member))

#ifndef SVR4_SHARED_LIBS

#define LM_ADDR(so) (SOLIB_EXTRACT_ADDRESS ((so) -> lm.lm_addr))

#define LM_NEXT(so) (SOLIB_EXTRACT_ADDRESS ((so) -> lm.lm_next))

#define LM_NAME(so) (SOLIB_EXTRACT_ADDRESS ((so) -> lm.lm_name))

/* Test for first link map entry; first entry is a shared library. */

#define IGNORE_FIRST_LINK_MAP_ENTRY(so) (0)

static struct link_dynamic dynamic_copy;

static struct link_dynamic_2 ld_2_copy;

static struct ld_debug debug_copy;

static CORE_ADDR debug_addr;

static CORE_ADDR flag_addr;

#else /* SVR4_SHARED_LIBS */

#define LM_ADDR(so) (SOLIB_EXTRACT_ADDRESS ((so) -> lm.l_addr))

#define LM_NEXT(so) (SOLIB_EXTRACT_ADDRESS ((so) -> lm.l_next))

#define LM_NAME(so) (SOLIB_EXTRACT_ADDRESS ((so) -> lm.l_name))

/* Test for first link map entry; first entry is the exec-file. */

#define IGNORE_FIRST_LINK_MAP_ENTRY(so) \

  (SOLIB_EXTRACT_ADDRESS ((so) -> lm.l_prev) == 0)

static struct r_debug debug_copy;

char shadow_contents[BREAKPOINT_MAX];   /* Stash old bkpt addr contents */

#endif /* !SVR4_SHARED_LIBS */

struct so_list

  {

    /* The following fields of the structure come directly from the

       dynamic linker's tables in the inferior, and are initialized by

       current_sos.  */

    struct so_list *next;       /* next structure in linked list */

    struct link_map lm;         /* copy of link map from inferior */

    CORE_ADDR lmaddr;           /* addr in inferior lm was read from */

    /* Shared object file name, exactly as it appears in the

       inferior's link map.  This may be a relative path, or something

       which needs to be looked up in LD_LIBRARY_PATH, etc.  We use it

       to tell which entries in the inferior's dynamic linker's link

       map we've already loaded.  */

    char so_original_name[MAX_PATH_SIZE];

    /* shared object file name, expanded to something GDB can open */

    char so_name[MAX_PATH_SIZE];

    /* The following fields of the structure are built from

       information gathered from the shared object file itself, and

       are initialized when we actually add it to our symbol tables.  */

    bfd *abfd;

    CORE_ADDR lmend;            /* upper addr bound of mapped object */

    char symbols_loaded;        /* flag: symbols read in yet? */

    char from_tty;              /* flag: print msgs? */

    struct objfile *objfile;    /* objfile for loaded lib */

    struct section_table *sections;

    struct section_table *sections_end;

    struct section_table *textsection;

  };

static struct so_list *so_list_head;    /* List of known shared objects */

static CORE_ADDR debug_base;    /* Base of dynamic linker structures */

static CORE_ADDR breakpoint_addr;       /* Address where end bkpt is set */

static int solib_cleanup_queued = 0;     /* make_run_cleanup called */

extern int

fdmatch PARAMS ((int, int));    /* In libiberty */

/* Local function prototypes */

static void

do_clear_solib PARAMS ((PTR));

static int

match_main PARAMS ((char *));

static void

special_symbol_handling PARAMS ((void));

static void

sharedlibrary_command PARAMS ((char *, int));

static int

enable_break PARAMS ((void));

static void

info_sharedlibrary_command PARAMS ((char *, int));

static int symbol_add_stub PARAMS ((PTR));

static CORE_ADDR

  first_link_map_member PARAMS ((void));

static CORE_ADDR

  locate_base PARAMS ((void));

static int solib_map_sections PARAMS ((PTR));

#ifdef SVR4_SHARED_LIBS

static CORE_ADDR

  elf_locate_base PARAMS ((void));

#else

static struct so_list *current_sos (void);

static void free_so (struct so_list *node);

static int

disable_break PARAMS ((void));

static void

allocate_rt_common_objfile PARAMS ((void));

static void

solib_add_common_symbols (CORE_ADDR);

#endif

void _initialize_solib PARAMS ((void));

/* If non-zero, this is a prefix that will be added to the front of the name

   shared libraries with an absolute filename for loading.  */

static char *solib_absolute_prefix = NULL;

/* If non-empty, this is a search path for loading non-absolute shared library

   symbol files.  This takes precedence over the environment variables PATH

   and LD_LIBRARY_PATH.  */

static char *solib_search_path = NULL;

/*

   LOCAL FUNCTION

   solib_map_sections -- open bfd and build sections for shared lib

   SYNOPSIS

   static int solib_map_sections (struct so_list *so)

   DESCRIPTION

   Given a pointer to one of the shared objects in our list

   of mapped objects, use the recorded name to open a bfd

   descriptor for the object, build a section table, and then

   relocate all the section addresses by the base address at

   which the shared object was mapped.

   FIXMES

   In most (all?) cases the shared object file name recorded in the

   dynamic linkage tables will be a fully qualified pathname.  For

   cases where it isn't, do we really mimic the systems search

   mechanism correctly in the below code (particularly the tilde

   expansion stuff?).

 */

static int

solib_map_sections (arg)

     PTR arg;

{

  struct so_list *so = (struct so_list *) arg;  /* catch_errors bogon */

  char *filename;

  char *scratch_pathname;

  int scratch_chan;

  struct section_table *p;

  struct cleanup *old_chain;

  bfd *abfd;

  filename = tilde_expand (so->so_name);

  if (solib_absolute_prefix && ROOTED_P (filename))

    /* Prefix shared libraries with absolute filenames with

       SOLIB_ABSOLUTE_PREFIX.  */

    {

      char *pfxed_fn;

      int pfx_len;

      pfx_len = strlen (solib_absolute_prefix);

      /* Remove trailing slashes.  */

      while (pfx_len > 0 && SLASH_P (solib_absolute_prefix[pfx_len - 1]))

        pfx_len--;

      pfxed_fn = xmalloc (pfx_len + strlen (filename) + 1);

      strcpy (pfxed_fn, solib_absolute_prefix);

      strcat (pfxed_fn, filename);

      free (filename);

      filename = pfxed_fn;

    }

  old_chain = make_cleanup (free, filename);

  scratch_chan = -1;

  if (solib_search_path)

    scratch_chan = openp (solib_search_path,

                          1, filename, O_RDONLY, 0, &scratch_pathname);

  if (scratch_chan < 0)

    scratch_chan = openp (get_in_environ (inferior_environ, "PATH"),

                          1, filename, O_RDONLY, 0, &scratch_pathname);

  if (scratch_chan < 0)

    {

      scratch_chan = openp (get_in_environ

                            (inferior_environ, "LD_LIBRARY_PATH"),

                            1, filename, O_RDONLY, 0, &scratch_pathname);

    }

  if (scratch_chan < 0)

    {

      perror_with_name (filename);

    }

  /* Leave scratch_pathname allocated.  abfd->name will point to it.  */

  abfd = bfd_fdopenr (scratch_pathname, gnutarget, scratch_chan);

  if (!abfd)

    {

      close (scratch_chan);

      error ("Could not open `%s' as an executable file: %s",

             scratch_pathname, bfd_errmsg (bfd_get_error ()));

    }

  /* Leave bfd open, core_xfer_memory and "info files" need it.  */

  so->abfd = abfd;

  abfd->cacheable = true;

  /* copy full path name into so_name, so that later symbol_file_add can find

     it */

  if (strlen (scratch_pathname) >= MAX_PATH_SIZE)

    error ("Full path name length of shared library exceeds MAX_PATH_SIZE in so_list structure.");

  strcpy (so->so_name, scratch_pathname);

  if (!bfd_check_format (abfd, bfd_object))

    {

      error ("\"%s\": not in executable format: %s.",

             scratch_pathname, bfd_errmsg (bfd_get_error ()));

    }

  if (build_section_table (abfd, &so->sections, &so->sections_end))

    {

      error ("Can't find the file sections in `%s': %s",

             bfd_get_filename (abfd), bfd_errmsg (bfd_get_error ()));

    }

  for (p = so->sections; p < so->sections_end; p++)

    {

      /* Relocate the section binding addresses as recorded in the shared

         object's file by the base address to which the object was actually

         mapped. */

      p->addr += LM_ADDR (so);

      p->endaddr += LM_ADDR (so);

      so->lmend = max (p->endaddr, so->lmend);

      if (STREQ (p->the_bfd_section->name, ".text"))

        {

          so->textsection = p;

        }

    }

  /* Free the file names, close the file now.  */

  do_cleanups (old_chain);

  return (1);

}

#ifndef SVR4_SHARED_LIBS

/* Allocate the runtime common object file.  */

static void

allocate_rt_common_objfile ()

{

  struct objfile *objfile;

  struct objfile *last_one;

  objfile = (struct objfile *) xmalloc (sizeof (struct objfile));

  memset (objfile, 0, sizeof (struct objfile));

  objfile->md = NULL;

  obstack_specify_allocation (&objfile->psymbol_cache.cache, 0, 0,

                              xmalloc, free);

  obstack_specify_allocation (&objfile->psymbol_obstack, 0, 0, xmalloc,

                              free);

  obstack_specify_allocation (&objfile->symbol_obstack, 0, 0, xmalloc,

                              free);

  obstack_specify_allocation (&objfile->type_obstack, 0, 0, xmalloc,

                              free);

  objfile->name = mstrsave (objfile->md, "rt_common");

  /* Add this file onto the tail of the linked list of other such files. */

  objfile->next = NULL;

  if (object_files == NULL)

    object_files = objfile;

  else

    {

      for (last_one = object_files;

           last_one->next;

           last_one = last_one->next);

      last_one->next = objfile;

    }

  rt_common_objfile = objfile;

}

/* Read all dynamically loaded common symbol definitions from the inferior

   and put them into the minimal symbol table for the runtime common

   objfile.  */

static void

solib_add_common_symbols (rtc_symp)

     CORE_ADDR rtc_symp;

{

  struct rtc_symb inferior_rtc_symb;

  struct nlist inferior_rtc_nlist;

  int len;

  char *name;

  /* Remove any runtime common symbols from previous runs.  */

  if (rt_common_objfile != NULL && rt_common_objfile->minimal_symbol_count)

    {

      obstack_free (&rt_common_objfile->symbol_obstack, 0);

      obstack_specify_allocation (&rt_common_objfile->symbol_obstack, 0, 0,

                                  xmalloc, free);

      rt_common_objfile->minimal_symbol_count = 0;

      rt_common_objfile->msymbols = NULL;

    }

  init_minimal_symbol_collection ();

  make_cleanup ((make_cleanup_func) discard_minimal_symbols, 0);

  while (rtc_symp)

    {

      read_memory (rtc_symp,

                   (char *) &inferior_rtc_symb,

                   sizeof (inferior_rtc_symb));

      read_memory (SOLIB_EXTRACT_ADDRESS (inferior_rtc_symb.rtc_sp),

                   (char *) &inferior_rtc_nlist,

                   sizeof (inferior_rtc_nlist));

      if (inferior_rtc_nlist.n_type == N_COMM)

        {

          /* FIXME: The length of the symbol name is not available, but in the

             current implementation the common symbol is allocated immediately

             behind the name of the symbol. */

          len = inferior_rtc_nlist.n_value - inferior_rtc_nlist.n_un.n_strx;

          name = xmalloc (len);

          read_memory (SOLIB_EXTRACT_ADDRESS (inferior_rtc_nlist.n_un.n_name),

                       name, len);

          /* Allocate the runtime common objfile if necessary. */

          if (rt_common_objfile == NULL)

            allocate_rt_common_objfile ();

          prim_record_minimal_symbol (name, inferior_rtc_nlist.n_value,

                                      mst_bss, rt_common_objfile);

          free (name);

        }

      rtc_symp = SOLIB_EXTRACT_ADDRESS (inferior_rtc_symb.rtc_next);

    }

  /* Install any minimal symbols that have been collected as the current

     minimal symbols for the runtime common objfile.  */

  install_minimal_symbols (rt_common_objfile);

}

#endif /* SVR4_SHARED_LIBS */

#ifdef SVR4_SHARED_LIBS

static CORE_ADDR

  bfd_lookup_symbol PARAMS ((bfd *, char *));

/*

   LOCAL FUNCTION

   bfd_lookup_symbol -- lookup the value for a specific symbol

   SYNOPSIS

   CORE_ADDR bfd_lookup_symbol (bfd *abfd, char *symname)

   DESCRIPTION

   An expensive way to lookup the value of a single symbol for

   bfd's that are only temporary anyway.  This is used by the

   shared library support to find the address of the debugger

   interface structures in the shared library.

   Note that 0 is specifically allowed as an error return (no

   such symbol).

 */

static CORE_ADDR

bfd_lookup_symbol (abfd, symname)

     bfd *abfd;

     char *symname;

{

  unsigned int storage_needed;

  asymbol *sym;

  asymbol **symbol_table;

  unsigned int number_of_symbols;

  unsigned int i;

  struct cleanup *back_to;

  CORE_ADDR symaddr = 0;

  storage_needed = bfd_get_symtab_upper_bound (abfd);

  if (storage_needed > 0)

    {

      symbol_table = (asymbol **) xmalloc (storage_needed);

      back_to = make_cleanup (free, (PTR) symbol_table);

      number_of_symbols = bfd_canonicalize_symtab (abfd, symbol_table);

      for (i = 0; i < number_of_symbols; i++)

        {

          sym = *symbol_table++;

          if (STREQ (sym->name, symname))

            {

              /* Bfd symbols are section relative. */

              symaddr = sym->value + sym->section->vma;

              break;

            }

        }

      do_cleanups (back_to);

    }

  return (symaddr);

}

#ifdef HANDLE_SVR4_EXEC_EMULATORS

/*

   Solaris BCP (the part of Solaris which allows it to run SunOS4

   a.out files) throws in another wrinkle. Solaris does not fill

   in the usual a.out link map structures when running BCP programs,

   the only way to get at them is via groping around in the dynamic

   linker.

   The dynamic linker and it's structures are located in the shared

   C library, which gets run as the executable's "interpreter" by

   the kernel.

   Note that we can assume nothing about the process state at the time

   we need to find these structures.  We may be stopped on the first

   instruction of the interpreter (C shared library), the first

   instruction of the executable itself, or somewhere else entirely

   (if we attached to the process for example).

 */

static char *debug_base_symbols[] =

{

  "r_debug",                    /* Solaris 2.3 */

  "_r_debug",                   /* Solaris 2.1, 2.2 */

  NULL

};

static int

look_for_base PARAMS ((int, CORE_ADDR));

/*

   LOCAL FUNCTION

   look_for_base -- examine file for each mapped address segment

   SYNOPSYS

   static int look_for_base (int fd, CORE_ADDR baseaddr)

   DESCRIPTION

   This function is passed to proc_iterate_over_mappings, which

   causes it to get called once for each mapped address space, with

   an open file descriptor for the file mapped to that space, and the

   base address of that mapped space.

   Our job is to find the debug base symbol in the file that this

   fd is open on, if it exists, and if so, initialize the dynamic

   linker structure base address debug_base.

   Note that this is a computationally expensive proposition, since

   we basically have to open a bfd on every call, so we specifically

   avoid opening the exec file.

 */

static int

look_for_base (fd, baseaddr)

     int fd;

     CORE_ADDR baseaddr;

{

  bfd *interp_bfd;

  CORE_ADDR address = 0;

  char **symbolp;

  /* If the fd is -1, then there is no file that corresponds to this

     mapped memory segment, so skip it.  Also, if the fd corresponds

     to the exec file, skip it as well. */

  if (fd == -1

      || (exec_bfd != NULL

          && fdmatch (fileno ((FILE *) (exec_bfd->iostream)), fd)))

    {

      return (0);

    }

  /* Try to open whatever random file this fd corresponds to.  Note that

     we have no way currently to find the filename.  Don't gripe about

     any problems we might have, just fail. */

  if ((interp_bfd = bfd_fdopenr ("unnamed", gnutarget, fd)) == NULL)

    {

      return (0);

    }

  if (!bfd_check_format (interp_bfd, bfd_object))

    {

      /* FIXME-leak: on failure, might not free all memory associated with

         interp_bfd.  */

      bfd_close (interp_bfd);

      return (0);

    }

  /* Now try to find our debug base symbol in this file, which we at

     least know to be a valid ELF executable or shared library. */

  for (symbolp = debug_base_symbols; *symbolp != NULL; symbolp++)

    {

      address = bfd_lookup_symbol (interp_bfd, *symbolp);

      if (address != 0)

        {

          break;

        }

    }

  if (address == 0)

    {

      /* FIXME-leak: on failure, might not free all memory associated with

         interp_bfd.  */

      bfd_close (interp_bfd);

      return (0);

    }

  /* Eureka!  We found the symbol.  But now we may need to relocate it

     by the base address.  If the symbol's value is less than the base

     address of the shared library, then it hasn't yet been relocated

     by the dynamic linker, and we have to do it ourself.  FIXME: Note

     that we make the assumption that the first segment that corresponds

     to the shared library has the base address to which the library

     was relocated. */

  if (address < baseaddr)

    {

      address += baseaddr;

    }

  debug_base = address;

  /* FIXME-leak: on failure, might not free all memory associated with

     interp_bfd.  */

  bfd_close (interp_bfd);

  return (1);

}

#endif /* HANDLE_SVR4_EXEC_EMULATORS */

/*

   LOCAL FUNCTION

   elf_locate_base -- locate the base address of dynamic linker structs

   for SVR4 elf targets.

   SYNOPSIS

   CORE_ADDR elf_locate_base (void)

   DESCRIPTION

   For SVR4 elf targets the address of the dynamic linker's runtime

   structure is contained within the dynamic info section in the

   executable file.  The dynamic section is also mapped into the

   inferior address space.  Because the runtime loader fills in the

   real address before starting the inferior, we have to read in the

   dynamic info section from the inferior address space.

   If there are any errors while trying to find the address, we

   silently return 0, otherwise the found address is returned.

 */

static CORE_ADDR

elf_locate_base ()

{

  sec_ptr dyninfo_sect;

  int dyninfo_sect_size;

  CORE_ADDR dyninfo_addr;

  char *buf;

  char *bufend;

  /* Find the start address of the .dynamic section.  */

  dyninfo_sect = bfd_get_section_by_name (exec_bfd, ".dynamic");

  if (dyninfo_sect == NULL)

    return 0;

  dyninfo_addr = bfd_section_vma (exec_bfd, dyninfo_sect);

  /* Read in .dynamic section, silently ignore errors.  */

  dyninfo_sect_size = bfd_section_size (exec_bfd, dyninfo_sect);

  buf = alloca (dyninfo_sect_size);

  if (target_read_memory (dyninfo_addr, buf, dyninfo_sect_size))

    return 0;

  /* Find the DT_DEBUG entry in the the .dynamic section.

     For mips elf we look for DT_MIPS_RLD_MAP, mips elf apparently has

     no DT_DEBUG entries.  */

#ifndef TARGET_ELF64

  for (bufend = buf + dyninfo_sect_size;

       buf < bufend;

       buf += sizeof (Elf32_External_Dyn))

    {

      Elf32_External_Dyn *x_dynp = (Elf32_External_Dyn *) buf;

      long dyn_tag;

      CORE_ADDR dyn_ptr;

      dyn_tag = bfd_h_get_32 (exec_bfd, (bfd_byte *) x_dynp->d_tag);

      if (dyn_tag == DT_NULL)

        break;

      else if (dyn_tag == DT_DEBUG)

        {

          dyn_ptr = bfd_h_get_32 (exec_bfd, (bfd_byte *) x_dynp->d_un.d_ptr);