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/* GDB routines for supporting auto-loaded scripts.

   Copyright (C) 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 "gdb_string.h"

#include "gdb_regex.h"

#include "top.h"

#include "exceptions.h"

#include "command.h"

#include "gdbcmd.h"

#include "observer.h"

#include "progspace.h"

#include "objfiles.h"

#include "python.h"

#include "cli/cli-cmds.h"

/* Internal-use flag to enable/disable auto-loading.

   This is true if we should auto-load python code when an objfile is opened,

   false otherwise.

   Both gdbpy_auto_load && gdbpy_global_auto_load must be true to enable

   auto-loading.

   This flag exists to facilitate deferring auto-loading during start-up

   until after ./.gdbinit has been read; it may augment the search directories

   used to find the scripts.  */

int gdbpy_global_auto_load = 1;

#ifdef HAVE_PYTHON

#include "python-internal.h"

/* NOTE: It's trivial to also support auto-loading normal gdb scripts.

   There has yet to be a need so it's not implemented.  */

/* The suffix of per-objfile scripts to auto-load.

   E.g. When the program loads libfoo.so, look for libfoo-gdb.py.  */

#define GDBPY_AUTO_FILE_NAME "-gdb.py"

/* The section to look for scripts (in file formats that support sections).

   Each entry in this section is a byte of value 1, and then the nul-terminated

   name of the script.  The script name may include a directory.

   The leading byte is to allow upward compatible extensions.  */

#define GDBPY_AUTO_SECTION_NAME ".debug_gdb_scripts"

/* For scripts specified in .debug_gdb_scripts, multiple objfiles may load

   the same script.  There's no point in loading the script multiple times,

   and there can be a lot of objfiles and scripts, so we keep track of scripts

   loaded this way.  */

struct auto_load_pspace_info

{

  /* For each program space we keep track of loaded scripts.  */

  struct htab *loaded_scripts;

};

/* Objects of this type are stored in the loaded script hash table.  */

struct loaded_script_entry

{

  /* Name as provided by the objfile.  */

  const char *name;

  /* Full path name or NULL if script wasn't found (or was otherwise

     inaccessible).  */

  const char *full_path;

};

/* User-settable option to enable/disable auto-loading:

   maint set python auto-load on|off

   This is true if we should auto-load python code when an objfile is opened,

   false otherwise.  */

static int gdbpy_auto_load = 1;

/* Per-program-space data key.  */

static const struct program_space_data *auto_load_pspace_data;

static void

auto_load_pspace_data_cleanup (struct program_space *pspace, void *arg)

{

  struct auto_load_pspace_info *info;

  info = program_space_data (pspace, auto_load_pspace_data);

  if (info != NULL)

    {

      if (info->loaded_scripts)

        htab_delete (info->loaded_scripts);

      xfree (info);

    }

}

/* Get the current autoload data.  If none is found yet, add it now.  This

   function always returns a valid object.  */

static struct auto_load_pspace_info *

get_auto_load_pspace_data (struct program_space *pspace)

{

  struct auto_load_pspace_info *info;

  info = program_space_data (pspace, auto_load_pspace_data);

  if (info == NULL)

    {

      info = XZALLOC (struct auto_load_pspace_info);

      set_program_space_data (pspace, auto_load_pspace_data, info);

    }

  return info;

}

/* Hash function for the loaded script hash.  */

static hashval_t

hash_loaded_script_entry (const void *data)

{

  const struct loaded_script_entry *e = data;

  return htab_hash_string (e->name);

}

/* Equality function for the loaded script hash.  */

static int

eq_loaded_script_entry (const void *a, const void *b)

{

  const struct loaded_script_entry *ea = a;

  const struct loaded_script_entry *eb = b;

  return strcmp (ea->name, eb->name) == 0;

}

/* Create the hash table used for loaded scripts.

   Each entry is hashed by the full path name.  */

static void

create_loaded_scripts_hash (struct auto_load_pspace_info *pspace_info)

{

  /* Choose 31 as the starting size of the hash table, somewhat arbitrarily.

     Space for each entry is obtained with one malloc so we can free them

     easily.  */

  pspace_info->loaded_scripts = htab_create (31,

                                             hash_loaded_script_entry,

                                             eq_loaded_script_entry,

                                             xfree);

}

/* Load scripts specified in OBJFILE.

   START,END delimit a buffer containing a list of nul-terminated

   file names.

   SOURCE_NAME is used in error messages.

   Scripts are found per normal "source -s" command processing.

   First the script is looked for in $cwd.  If not found there the

   source search path is used.

   The section contains a list of path names of files containing

   python code to load.  Each path is null-terminated.  */

static void

source_section_scripts (struct objfile *objfile, const char *source_name,

                        const char *start, const char *end)

{

  const char *p;

  struct auto_load_pspace_info *pspace_info;

  struct loaded_script_entry **slot, entry;

  pspace_info = get_auto_load_pspace_data (current_program_space);

  if (pspace_info->loaded_scripts == NULL)

    create_loaded_scripts_hash (pspace_info);

  for (p = start; p < end; ++p)

    {

      const char *file;

      FILE *stream;

      char *full_path;

      int opened, in_hash_table;

      if (*p != 1)

        {

          warning (_("Invalid entry in %s section"), GDBPY_AUTO_SECTION_NAME);

          /* We could try various heuristics to find the next valid entry,

             but it's safer to just punt.  */

          break;

        }

      file = ++p;

      while (p < end && *p != '\0')

        ++p;

      if (p == end)

        {

          char *buf = alloca (p - file + 1);

          memcpy (buf, file, p - file);

          buf[p - file] = '\0';

          warning (_("Non-null-terminated path in %s: %s"),

                   source_name, buf);

          /* Don't load it.  */

          break;

        }

      if (p == file)

        {

          warning (_("Empty path in %s"), source_name);

          continue;

        }

      opened = find_and_open_script (file, 1 /*search_path*/,

                                     &stream, &full_path);

      /* If the file is not found, we still record the file in the hash table,

         we only want to print an error message once.

         IWBN if complaints.c were more general-purpose.  */

      entry.name = file;

      if (opened)

        entry.full_path = full_path;

      else

        entry.full_path = NULL;

      slot = ((struct loaded_script_entry **)

              htab_find_slot (pspace_info->loaded_scripts,

                              &entry, INSERT));

      in_hash_table = *slot != NULL;

      /* If this file is not in the hash table, add it.  */

      if (! in_hash_table)

        {

          char *p;

          *slot = xmalloc (sizeof (**slot)

                           + strlen (file) + 1

                           + (opened ? (strlen (full_path) + 1) : 0));

          p = ((char*) *slot) + sizeof (**slot);

          strcpy (p, file);

          (*slot)->name = p;

          if (opened)

            {

              p += strlen (p) + 1;

              strcpy (p, full_path);

              (*slot)->full_path = p;

            }

          else

            (*slot)->full_path = NULL;

        }

      if (opened)

        free (full_path);

      if (! opened)

        {

          /* We don't throw an error, the program is still debuggable.

             Check in_hash_table to only print the warning once.  */

          if (! in_hash_table)

            warning (_("%s (referenced in %s): %s"),

                     file, GDBPY_AUTO_SECTION_NAME, safe_strerror (errno));

          continue;

        }

      /* If this file is not currently loaded, load it.  */

      if (! in_hash_table)

        source_python_script_for_objfile (objfile, stream, file);

    }

}

/* Load scripts specified in section SECTION_NAME of OBJFILE.  */

static void

auto_load_section_scripts (struct objfile *objfile, const char *section_name)

{

  bfd *abfd = objfile->obfd;

  asection *scripts_sect;

  bfd_size_type size;

  char *p;

  struct cleanup *cleanups;

  scripts_sect = bfd_get_section_by_name (abfd, section_name);

  if (scripts_sect == NULL)

    return;

  size = bfd_get_section_size (scripts_sect);

  p = xmalloc (size);

  cleanups = make_cleanup (xfree, p);

  if (bfd_get_section_contents (abfd, scripts_sect, p, (file_ptr) 0, size))

    source_section_scripts (objfile, section_name, p, p + size);

  else

    warning (_("Couldn't read %s section of %s"),

             section_name, bfd_get_filename (abfd));

  do_cleanups (cleanups);

}

/* Clear the table of loaded section scripts.  */

static void

clear_section_scripts (void)

{

  struct program_space *pspace = current_program_space;

  struct auto_load_pspace_info *info;

  info = program_space_data (pspace, auto_load_pspace_data);

  if (info != NULL && info->loaded_scripts != NULL)

    {

      htab_delete (info->loaded_scripts);

      info->loaded_scripts = NULL;

    }

}

/* Look for the auto-load script associated with OBJFILE and load it.  */

static void

auto_load_objfile_script (struct objfile *objfile, const char *suffix)

{

  char *realname;

  char *filename, *debugfile;

  int len;

  FILE *input;

  struct cleanup *cleanups;

  realname = gdb_realpath (objfile->name);

  len = strlen (realname);

  filename = xmalloc (len + strlen (suffix) + 1);

  memcpy (filename, realname, len);

  strcpy (filename + len, suffix);

  cleanups = make_cleanup (xfree, filename);

  make_cleanup (xfree, realname);

  input = fopen (filename, "r");

  debugfile = filename;

  if (!input && debug_file_directory)

    {

      /* Also try the same file in the separate debug info directory.  */

      debugfile = xmalloc (strlen (filename)

                           + strlen (debug_file_directory) + 1);

      strcpy (debugfile, debug_file_directory);

      /* FILENAME is absolute, so we don't need a "/" here.  */

      strcat (debugfile, filename);

      make_cleanup (xfree, debugfile);

      input = fopen (debugfile, "r");

    }

  if (!input && gdb_datadir)

    {

      /* Also try the same file in a subdirectory of gdb's data

         directory.  */

      debugfile = xmalloc (strlen (gdb_datadir) + strlen (filename)

                           + strlen ("/auto-load") + 1);

      strcpy (debugfile, gdb_datadir);

      strcat (debugfile, "/auto-load");

      /* FILENAME is absolute, so we don't need a "/" here.  */

      strcat (debugfile, filename);

      make_cleanup (xfree, debugfile);

      input = fopen (debugfile, "r");

    }

  if (input)

    {

      source_python_script_for_objfile (objfile, input, debugfile);

      fclose (input);

    }

  do_cleanups (cleanups);

}

/* This is a new_objfile observer callback to auto-load scripts.

   Two flavors of auto-loaded scripts are supported.

   1) based on the path to the objfile

   2) from .debug_gdb_scripts section  */

static void

auto_load_new_objfile (struct objfile *objfile)

{

  if (!objfile)

    {

      /* OBJFILE is NULL when loading a new "main" symbol-file.  */

      clear_section_scripts ();

      return;

    }

  if (!objfile->name)

    return;

  load_auto_scripts_for_objfile (objfile);

}

/* Load any auto-loaded scripts for OBJFILE.  */

void

load_auto_scripts_for_objfile (struct objfile *objfile)

{

  if (gdbpy_auto_load && gdbpy_global_auto_load)

    {

      auto_load_objfile_script (objfile, GDBPY_AUTO_FILE_NAME);

      auto_load_section_scripts (objfile, GDBPY_AUTO_SECTION_NAME);

    }

}

/* Traversal function for htab_traverse.

   Print the entry if specified in the regex.  */

static int

maybe_print_section_script (void **slot, void *info)

{

  struct loaded_script_entry *entry = *slot;

  if (re_exec (entry->name))

    {

      printf_filtered (_("Script name: %s\n"), entry->name);

      printf_filtered (_("  Full name: %s\n"),

                       entry->full_path ? entry->full_path : _("unknown"));

    }

  return 1;

}

/* "maint print section-scripts" command.  */

static void

maintenance_print_section_scripts (char *pattern, int from_tty)

{

  struct auto_load_pspace_info *pspace_info;

  dont_repeat ();

  if (pattern && *pattern)

    {

      char *re_err = re_comp (pattern);

      if (re_err)

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

      printf_filtered (_("Objfile scripts matching %s:\n"), pattern);

    }

  else

    {

      re_comp ("");

      printf_filtered (_("Objfile scripts:\n"));

    }

  pspace_info = get_auto_load_pspace_data (current_program_space);

  if (pspace_info == NULL || pspace_info->loaded_scripts == NULL)

    return;

  immediate_quit++;

  htab_traverse_noresize (pspace_info->loaded_scripts,

                          maybe_print_section_script, NULL);

  immediate_quit--;

}

void

gdbpy_initialize_auto_load (void)

{

  auto_load_pspace_data

    = register_program_space_data_with_cleanup (auto_load_pspace_data_cleanup);

  observer_attach_new_objfile (auto_load_new_objfile);

  add_setshow_boolean_cmd ("auto-load", class_maintenance,

                           &gdbpy_auto_load, _("\

Enable or disable auto-loading of Python code when an object is opened."), _("\

Show whether Python code will be auto-loaded when an object is opened."), _("\

Enables or disables auto-loading of Python code when an object is opened."),

                           NULL, NULL,

                           &set_python_list,

                           &show_python_list);

  add_cmd ("section-scripts", class_maintenance, maintenance_print_section_scripts,

           _("Print dump of auto-loaded section scripts matching REGEXP."),

           &maintenanceprintlist);

}

#else /* ! HAVE_PYTHON */

void

load_auto_scripts_for_objfile (struct objfile *objfile)

{

}

#endif /* ! HAVE_PYTHON */