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

   Copyright (C) 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,

   2000, 2001, 2002, 2003, 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 <sys/types.h>

#include <fcntl.h>

#include "gdb_string.h"

#include "symtab.h"

#include "bfd.h"

#include "symfile.h"

#include "objfiles.h"

#include "exceptions.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"

#include "completer.h"

#include "filenames.h"          /* for DOSish file names */

#include "exec.h"

#include "solist.h"

#include "observer.h"

#include "readline/readline.h"

#include "remote.h"

#include "solib.h"

#include "interps.h"

/* Architecture-specific operations.  */

/* Per-architecture data key.  */

static struct gdbarch_data *solib_data;

static void *

solib_init (struct obstack *obstack)

{

  struct target_so_ops **ops;

  ops = OBSTACK_ZALLOC (obstack, struct target_so_ops *);

  *ops = current_target_so_ops;

  return ops;

}

static struct target_so_ops *

solib_ops (struct gdbarch *gdbarch)

{

  struct target_so_ops **ops = gdbarch_data (gdbarch, solib_data);

  return *ops;

}

/* Set the solib operations for GDBARCH to NEW_OPS.  */

void

set_solib_ops (struct gdbarch *gdbarch, struct target_so_ops *new_ops)

{

  struct target_so_ops **ops = gdbarch_data (gdbarch, solib_data);

  *ops = new_ops;

}

/* external data declarations */

/* FIXME: gdbarch needs to control this variable, or else every

   configuration needs to call set_solib_ops.  */

struct target_so_ops *current_target_so_ops;

/* List of known shared objects */

#define so_list_head current_program_space->so_list

/* Local function prototypes */

/* 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;

static void

show_solib_search_path (struct ui_file *file, int from_tty,

                        struct cmd_list_element *c, const char *value)

{

  fprintf_filtered (file, _("\

The search path for loading non-absolute shared library symbol files is %s.\n"),

                    value);

}

/*

   GLOBAL FUNCTION

   solib_find -- Find a shared library file.

   SYNOPSIS

   char *solib_find (char *in_pathname, int *fd);

   DESCRIPTION

   Global variable GDB_SYSROOT is used as a prefix directory

   to search for shared libraries if they have an absolute path.

   Global variable SOLIB_SEARCH_PATH is used as a prefix directory

   (or set of directories, as in LD_LIBRARY_PATH) to search for all

   shared libraries if not found in GDB_SYSROOT.

   Search algorithm:

   * If there is a gdb_sysroot and path is absolute:

   *   Search for gdb_sysroot/path.

   * else

   *   Look for it literally (unmodified).

   * Look in SOLIB_SEARCH_PATH.

   * If available, use target defined search function.

   * If gdb_sysroot is NOT set, perform the following two searches:

   *   Look in inferior's $PATH.

   *   Look in inferior's $LD_LIBRARY_PATH.

   *

   * The last check avoids doing this search when targetting remote

   * machines since gdb_sysroot will almost always be set.

   RETURNS

   Full pathname of the shared library file, or NULL if not found.

   (The pathname is malloc'ed; it needs to be freed by the caller.)

   *FD is set to either -1 or an open file handle for the library.  */

char *

solib_find (char *in_pathname, int *fd)

{

  struct target_so_ops *ops = solib_ops (target_gdbarch);

  int found_file = -1;

  char *temp_pathname = NULL;

  int gdb_sysroot_is_empty;

  gdb_sysroot_is_empty = (gdb_sysroot == NULL || *gdb_sysroot == 0);

  if (! IS_ABSOLUTE_PATH (in_pathname) || gdb_sysroot_is_empty)

    temp_pathname = in_pathname;

  else

    {

      int prefix_len = strlen (gdb_sysroot);

      /* Remove trailing slashes from absolute prefix.  */

      while (prefix_len > 0

             && IS_DIR_SEPARATOR (gdb_sysroot[prefix_len - 1]))

        prefix_len--;

      /* Cat the prefixed pathname together.  */

      temp_pathname = alloca (prefix_len + strlen (in_pathname) + 1);

      strncpy (temp_pathname, gdb_sysroot, prefix_len);

      temp_pathname[prefix_len] = '\0';

      strcat (temp_pathname, in_pathname);

    }

  /* Handle remote files.  */

  if (remote_filename_p (temp_pathname))

    {

      *fd = -1;

      return xstrdup (temp_pathname);

    }

  /* Now see if we can open it.  */

  found_file = open (temp_pathname, O_RDONLY | O_BINARY, 0);

  /* We try to find the library in various ways.  After each attempt

     (except for the one above), either found_file >= 0 and

     temp_pathname is a malloc'd string, or found_file < 0 and

     temp_pathname does not point to storage that needs to be

     freed.  */

    if (found_file < 0)

      temp_pathname = NULL;

    else

      temp_pathname = xstrdup (temp_pathname);

  /* If the search in gdb_sysroot failed, and the path name is

     absolute at this point, make it relative.  (openp will try and open the

     file according to its absolute path otherwise, which is not what we want.)

     Affects subsequent searches for this solib.  */

  if (found_file < 0 && IS_ABSOLUTE_PATH (in_pathname))

    {

      /* First, get rid of any drive letters etc.  */

      while (!IS_DIR_SEPARATOR (*in_pathname))

        in_pathname++;

      /* Next, get rid of all leading dir separators.  */

      while (IS_DIR_SEPARATOR (*in_pathname))

        in_pathname++;

    }

  /* If not found, search the solib_search_path (if any).  */

  if (found_file < 0 && solib_search_path != NULL)

    found_file = openp (solib_search_path, OPF_TRY_CWD_FIRST,

                        in_pathname, O_RDONLY | O_BINARY, &temp_pathname);

  /* If not found, next search the solib_search_path (if any) for the basename

     only (ignoring the path).  This is to allow reading solibs from a path

     that differs from the opened path.  */

  if (found_file < 0 && solib_search_path != NULL)

    found_file = openp (solib_search_path, OPF_TRY_CWD_FIRST,

                        lbasename (in_pathname), O_RDONLY | O_BINARY,

                        &temp_pathname);

  /* If not found, try to use target supplied solib search method */

  if (found_file < 0 && ops->find_and_open_solib)

    found_file = ops->find_and_open_solib (in_pathname, O_RDONLY | O_BINARY,

                                           &temp_pathname);

  /* If not found, next search the inferior's $PATH environment variable. */

  if (found_file < 0 && gdb_sysroot_is_empty)

    found_file = openp (get_in_environ (current_inferior ()->environment,

                                        "PATH"),

                        OPF_TRY_CWD_FIRST, in_pathname, O_RDONLY | O_BINARY,

                        &temp_pathname);

  /* If not found, next search the inferior's $LD_LIBRARY_PATH

     environment variable. */

  if (found_file < 0 && gdb_sysroot_is_empty)

    found_file = openp (get_in_environ (current_inferior ()->environment,

                                        "LD_LIBRARY_PATH"),

                        OPF_TRY_CWD_FIRST, in_pathname, O_RDONLY | O_BINARY,

                        &temp_pathname);

  *fd = found_file;

  return temp_pathname;

}

/* Open and return a BFD for the shared library PATHNAME.  If FD is not -1,

   it is used as file handle to open the file.  Throws an error if the file

   could not be opened.  Handles both local and remote file access.

   PATHNAME must be malloc'ed by the caller.  If successful, the new BFD's

   name will point to it.  If unsuccessful, PATHNAME will be freed and the

   FD will be closed (unless FD was -1).  */

bfd *

solib_bfd_fopen (char *pathname, int fd)

{

  bfd *abfd;

  if (remote_filename_p (pathname))

    {

      gdb_assert (fd == -1);

      abfd = remote_bfd_open (pathname, gnutarget);

    }

  else

    {

      abfd = bfd_fopen (pathname, gnutarget, FOPEN_RB, fd);

      if (abfd)

        bfd_set_cacheable (abfd, 1);

      else if (fd != -1)

        close (fd);

    }

  if (!abfd)

    {

      make_cleanup (xfree, pathname);

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

             pathname, bfd_errmsg (bfd_get_error ()));

    }

  return abfd;

}

/* Find shared library PATHNAME and open a BFD for it.  */

bfd *

solib_bfd_open (char *pathname)

{

  char *found_pathname;

  int found_file;

  bfd *abfd;

  const struct bfd_arch_info *b;

  /* Search for shared library file.  */

  found_pathname = solib_find (pathname, &found_file);

  if (found_pathname == NULL)

    perror_with_name (pathname);

  /* Open bfd for shared library.  */

  abfd = solib_bfd_fopen (found_pathname, found_file);

  /* Check bfd format.  */

  if (!bfd_check_format (abfd, bfd_object))

    {

      bfd_close (abfd);

      make_cleanup (xfree, found_pathname);

      error (_("`%s': not in executable format: %s"),

             found_pathname, bfd_errmsg (bfd_get_error ()));

    }

  /* Check bfd arch.  */

  b = gdbarch_bfd_arch_info (target_gdbarch);

  if (!b->compatible (b, bfd_get_arch_info (abfd)))

    warning (_("`%s': Shared library architecture %s is not compatible "

               "with target architecture %s."), found_pathname,

             bfd_get_arch_info (abfd)->printable_name, b->printable_name);

  return abfd;

}

/*

   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 (void *arg)

{

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

  struct target_so_ops *ops = solib_ops (target_gdbarch);

  char *filename;

  struct target_section *p;

  struct cleanup *old_chain;

  bfd *abfd;

  filename = tilde_expand (so->so_name);

  old_chain = make_cleanup (xfree, filename);

  abfd = ops->bfd_open (filename);

  do_cleanups (old_chain);

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

  so->abfd = gdb_bfd_ref (abfd);

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

     can find it */

  if (strlen (bfd_get_filename (abfd)) >= SO_NAME_MAX_PATH_SIZE)

    error (_("Shared library file name is too long."));

  strcpy (so->so_name, bfd_get_filename (abfd));

  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. */

      ops->relocate_section_addresses (so, p);

      /* If the target didn't provide information about the address

         range of the shared object, assume we want the location of

         the .text section.  */

      if (so->addr_low == 0 && so->addr_high == 0

          && strcmp (p->the_bfd_section->name, ".text") == 0)

        {

          so->addr_low = p->addr;

          so->addr_high = p->endaddr;

        }

    }

  return (1);

}

/* LOCAL FUNCTION

   free_so --- free a `struct so_list' object

   SYNOPSIS

   void free_so (struct so_list *so)

   DESCRIPTION

   Free the storage associated with the `struct so_list' object SO.

   If we have opened a BFD for SO, close it.

   The caller is responsible for removing SO from whatever list it is

   a member of.  If we have placed SO's sections in some target's

   section table, the caller is responsible for removing them.

   This function doesn't mess with objfiles at all.  If there is an

   objfile associated with SO that needs to be removed, the caller is

   responsible for taking care of that.  */

void

free_so (struct so_list *so)

{

  struct target_so_ops *ops = solib_ops (target_gdbarch);

  if (so->sections)

    xfree (so->sections);

  gdb_bfd_unref (so->abfd);

  ops->free_so (so);

  xfree (so);

}

/* Return address of first so_list entry in master shared object list.  */

struct so_list *

master_so_list (void)

{

  return so_list_head;

}

static void

symbol_add_stub (struct so_list *so, int flags)

{

  struct section_addr_info *sap;

  /* Have we already loaded this shared object?  */

  ALL_OBJFILES (so->objfile)

    {

      if (strcmp (so->objfile->name, so->so_name) == 0)

        return;

    }

  sap = build_section_addr_info_from_section_table (so->sections,

                                                    so->sections_end);

  so->objfile = symbol_file_add_from_bfd (so->abfd, flags, sap, OBJF_SHARED);

  free_section_addr_info (sap);

  return;

}

/* Read in symbols for shared object SO.  If SYMFILE_VERBOSE is set in FLAGS,

   be chatty about it.  Return non-zero if any symbols were actually

   loaded.  */

int

solib_read_symbols (struct so_list *so, int flags)

{

  const int from_tty = flags & SYMFILE_VERBOSE;

  if (so->symbols_loaded)

    {

      if (from_tty || info_verbose)

        printf_unfiltered (_("Symbols already loaded for %s\n"), so->so_name);

    }

  else if (so->abfd == NULL)

    {

      if (from_tty || info_verbose)

        printf_unfiltered (_("Symbol file not found for %s\n"), so->so_name);

    }

  else

    {

      volatile struct gdb_exception exception;

      TRY_CATCH (exception, RETURN_MASK_ALL)

        {

          symbol_add_stub (so, flags);

        }

      if (exception.reason != 0)

        {

          exception_fprintf (gdb_stderr, exception,

                             "Error while reading shared library symbols:\n");

          return 0;

        }

      if (from_tty || info_verbose)

        printf_unfiltered (_("Loaded symbols for %s\n"), so->so_name);

      so->symbols_loaded = 1;

      return 1;

    }

  return 0;

}

/* LOCAL FUNCTION

   update_solib_list --- synchronize GDB's shared object list with inferior's

   SYNOPSIS

   void update_solib_list (int from_tty, struct target_ops *TARGET)

   Extract the list of currently loaded shared objects from the

   inferior, and compare it with the list of shared objects currently

   in GDB's so_list_head list.  Edit so_list_head to bring it in sync

   with the inferior's new list.

   If we notice that the inferior has unloaded some shared objects,

   free any symbolic info GDB had read about those shared objects.

   Don't load symbolic info for any new shared objects; just add them

   to the list, and leave their symbols_loaded flag clear.

   If FROM_TTY is non-null, feel free to print messages about what

   we're doing.

   If TARGET is non-null, add the sections of all new shared objects

   to TARGET's section table.  Note that this doesn't remove any

   sections for shared objects that have been unloaded, and it

   doesn't check to see if the new shared objects are already present in

   the section table.  But we only use this for core files and

   processes we've just attached to, so that's okay.  */

static void

update_solib_list (int from_tty, struct target_ops *target)

{

  struct target_so_ops *ops = solib_ops (target_gdbarch);

  struct so_list *inferior = ops->current_sos();

  struct so_list *gdb, **gdb_link;

  /* We can reach here due to changing solib-search-path or the

     sysroot, before having any inferior.  */

  if (target_has_execution && !ptid_equal (inferior_ptid, null_ptid))

    {

      struct inferior *inf = current_inferior ();

      /* If we are attaching to a running process for which we

         have not opened a symbol file, we may be able to get its

         symbols now!  */

      if (inf->attach_flag && symfile_objfile == NULL)

        catch_errors (ops->open_symbol_file_object, &from_tty,

                      "Error reading attached process's symbol file.\n",

                      RETURN_MASK_ALL);

    }

  /* GDB and the inferior's dynamic linker each maintain their own

     list of currently loaded shared objects; we want to bring the

     former in sync with the latter.  Scan both lists, seeing which

     shared objects appear where.  There are three cases:

     - A shared object appears on both lists.  This means that GDB

     knows about it already, and it's still loaded in the inferior.

     Nothing needs to happen.

     - A shared object appears only on GDB's list.  This means that

     the inferior has unloaded it.  We should remove the shared

     object from GDB's tables.

     - A shared object appears only on the inferior's list.  This

     means that it's just been loaded.  We should add it to GDB's

     tables.

     So we walk GDB's list, checking each entry to see if it appears

     in the inferior's list too.  If it does, no action is needed, and

     we remove it from the inferior's list.  If it doesn't, the

     inferior has unloaded it, and we remove it from GDB's list.  By

     the time we're done walking GDB's list, the inferior's list

     contains only the new shared objects, which we then add.  */

  gdb = so_list_head;

  gdb_link = &so_list_head;

  while (gdb)

    {

      struct so_list *i = inferior;

      struct so_list **i_link = &inferior;

      /* Check to see whether the shared object *gdb also appears in

         the inferior's current list.  */

      while (i)

        {

          if (ops->same)

            {

              if (ops->same (gdb, i))

                break;

            }

          else

            {

              if (! strcmp (gdb->so_original_name, i->so_original_name))

                break;

            }

          i_link = &i->next;

          i = *i_link;

        }

      /* If the shared object appears on the inferior's list too, then

         it's still loaded, so we don't need to do anything.  Delete

         it from the inferior's list, and leave it on GDB's list.  */

      if (i)

        {

          *i_link = i->next;

          free_so (i);

          gdb_link = &gdb->next;

          gdb = *gdb_link;

        }

      /* If it's not on the inferior's list, remove it from GDB's tables.  */

      else

        {

          /* Notify any observer that the shared object has been

             unloaded before we remove it from GDB's tables.  */

          observer_notify_solib_unloaded (gdb);

          *gdb_link = gdb->next;

          /* Unless the user loaded it explicitly, free SO's objfile.  */

          if (gdb->objfile && ! (gdb->objfile->flags & OBJF_USERLOADED))

            free_objfile (gdb->objfile);

          /* Some targets' section tables might be referring to

             sections from so->abfd; remove them.  */

          remove_target_sections (gdb->abfd);

          free_so (gdb);

          gdb = *gdb_link;

        }

    }

  /* Now the inferior's list contains only shared objects that don't

     appear in GDB's list --- those that are newly loaded.  Add them

     to GDB's shared object list.  */

  if (inferior)

    {

      struct so_list *i;

      /* Add the new shared objects to GDB's list.  */

      *gdb_link = inferior;

      /* Fill in the rest of each of the `struct so_list' nodes.  */

      for (i = inferior; i; i = i->next)

        {

          i->from_tty = from_tty;

          i->pspace = current_program_space;

          /* Fill in the rest of the `struct so_list' node.  */

          catch_errors (solib_map_sections, i,

                        "Error while mapping shared library sections:\n",

                        RETURN_MASK_ALL);

          /* Add the shared object's sections to the current set of

             file section tables.  Do this immediately after mapping

             the object so that later nodes in the list can query this

             object, as is needed in solib-osf.c.  */

          add_target_sections (i->sections, i->sections_end);

          /* Notify any observer that the shared object has been

             loaded now that we've added it to GDB's tables.  */

          observer_notify_solib_loaded (i);

        }

    }

}

/* Return non-zero if NAME is the libpthread shared library.

   Uses a fairly simplistic heuristic approach where we check

   the file name against "/libpthread".  This can lead to false

   positives, but this should be good enough in practice.  */

int

libpthread_name_p (const char *name)

{

  return (strstr (name, "/libpthread") != NULL);

}

/* Return non-zero if SO is the libpthread shared library.  */

static int

libpthread_solib_p (struct so_list *so)

{

  return libpthread_name_p (so->so_name);

}

/* GLOBAL FUNCTION

   solib_add -- read in symbol info for newly added shared libraries

   SYNOPSIS

   void solib_add (char *pattern, int from_tty, struct target_ops

   *TARGET, int readsyms)

   DESCRIPTION

   Read in symbolic information for any shared objects whose names

   match PATTERN.  (If we've already read a shared object's symbol

   info, leave it alone.)  If PATTERN is zero, read them all.

   If READSYMS is 0, defer reading symbolic information until later

   but still do any needed low level processing.

   FROM_TTY and TARGET are as described for update_solib_list, above.  */

void

solib_add (char *pattern, int from_tty, struct target_ops *target, int readsyms)

{

  struct so_list *gdb;

  if (pattern)

    {

      char *re_err = re_comp (pattern);

      if (re_err)

        error (_("Invalid regexp: %s"), re_err);

    }

  update_solib_list (from_tty, target);

  /* Walk the list of currently loaded shared libraries, and read

     symbols for any that match the pattern --- or any whose symbols

     aren't already loaded, if no pattern was given.  */

  {

    int any_matches = 0;

    int loaded_any_symbols = 0;

    const int flags =

        SYMFILE_DEFER_BP_RESET | (from_tty ? SYMFILE_VERBOSE : 0);

    for (gdb = so_list_head; gdb; gdb = gdb->next)

      if (! pattern || re_exec (gdb->so_name))

        {

          /* Normally, we would read the symbols from that library

             only if READSYMS is set.  However, we're making a small

             exception for the pthread library, because we sometimes

             need the library symbols to be loaded in order to provide

             thread support (x86-linux for instance).  */

          const int add_this_solib =

            (readsyms || libpthread_solib_p (gdb));