glibc/elf/dl-open.c
Ulrich Drepper 9710f75d4a Update.
2002-02-03  Andreas Schwab  <schwab@suse.de>

	* sysdeps/posix/readv.c: Use ssize_t for bytes_read.
	* sysdeps/posix/writev.c: Use ssize_t for bytes_written.  Fix comment.

2002-02-03  Thorsten Kukuk  <kukuk@suse.de>

	* sysdeps/posix/writev.c: Check for ssize_t overflow, don't use
	alloca if the memory reqirements are too high.

2002-02-03  Ulrich Drepper  <drepper@redhat.com>

	* elf/dl-load.c (decompose_rpath): Avoid using strstr.
	* elf/dl-minimal.c (_strerror_r): Use _itoa instead of _itoa_word since
	the former is available anyway and speed isn't important here.
	* elf/dl-misc.c (_dl_debug_vdprintf): Likewise.
	* elf/dl-version.c (match_symbol): Likewise.
	(_dl_check_map_versions): Likewise.
	* elf/rtld.c (process_envvars): Likewise.
	(print_statistics): Likewise.
	* sysdeps/generic/dl-sysdep.c (_dl_show_auxv): Likewise.
	* elf/dl-minimal.c (_itoa): Always define it.  Make it work for all
	bases.  Add assert to catch uses of unimplemented features.
	(__strsep): Add assert to catch uses of unimplemented features.
	* elf/dl-object.c (_dl_new_object): Don't use rawmemchr.  Use strchr
	and avoid inline optimization.
	* elf/rtld.c (process_envvars): Likewise.
	* elf/dl-open.c: Don't include <stdio-common/_itoa.h>.
	* elf/dl-profile.c (_dl_start_profile): Help compiler to avoid ffs.
	* elf/rtld.c (dl_main): Avoid strsep inline optimization.

	* stdio-common/_itoa.h: Minor simplifications of the code.
	* stdio-common/_itoa.c: Likewise.

	* elf/dl-reloc.c (_dl_relocate_object): Use _dl_debug_printf
	instead of _dl_printf for debugging info output.

	* sysdeps/mips/atomicity.h (exchange_and_add): Use branch likely.
2002-02-03 19:39:52 +00:00

494 lines
14 KiB
C

/* Load a shared object at runtime, relocate it, and run its initializer.
Copyright (C) 1996-2001, 2002 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#include <assert.h>
#include <dlfcn.h>
#include <errno.h>
#include <libintl.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/mman.h> /* Check whether MAP_COPY is defined. */
#include <sys/param.h>
#include <bits/libc-lock.h>
#include <ldsodefs.h>
#include <bp-sym.h>
#include <dl-dst.h>
extern ElfW(Addr) _dl_sysdep_start (void **start_argptr,
void (*dl_main) (const ElfW(Phdr) *phdr,
ElfW(Word) phnum,
ElfW(Addr) *user_entry));
weak_extern (BP_SYM (_dl_sysdep_start))
extern int __libc_multiple_libcs; /* Defined in init-first.c. */
extern int __libc_argc;
extern char **__libc_argv;
extern char **__environ;
/* Undefine the following for debugging. */
/* #define SCOPE_DEBUG 1 */
#ifdef SCOPE_DEBUG
static void show_scope (struct link_map *new);
#endif
/* We must be carefull not to leave us in an inconsistent state. Thus we
catch any error and re-raise it after cleaning up. */
struct dl_open_args
{
const char *file;
int mode;
const void *caller;
struct link_map *map;
};
static int
add_to_global (struct link_map *new)
{
struct link_map **new_global;
unsigned int to_add = 0;
unsigned int cnt;
/* Count the objects we have to put in the global scope. */
for (cnt = 0; cnt < new->l_searchlist.r_nlist; ++cnt)
if (new->l_searchlist.r_list[cnt]->l_global == 0)
++to_add;
/* The symbols of the new objects and its dependencies are to be
introduced into the global scope that will be used to resolve
references from other dynamically-loaded objects.
The global scope is the searchlist in the main link map. We
extend this list if necessary. There is one problem though:
since this structure was allocated very early (before the libc
is loaded) the memory it uses is allocated by the malloc()-stub
in the ld.so. When we come here these functions are not used
anymore. Instead the malloc() implementation of the libc is
used. But this means the block from the main map cannot be used
in an realloc() call. Therefore we allocate a completely new
array the first time we have to add something to the locale scope. */
if (GL(dl_global_scope_alloc) == 0)
{
/* This is the first dynamic object given global scope. */
GL(dl_global_scope_alloc) = GL(dl_main_searchlist)->r_nlist + to_add + 8;
new_global = (struct link_map **)
malloc (GL(dl_global_scope_alloc) * sizeof (struct link_map *));
if (new_global == NULL)
{
GL(dl_global_scope_alloc) = 0;
nomem:
_dl_signal_error (ENOMEM, new->l_libname->name, NULL,
N_("cannot extend global scope"));
return 1;
}
/* Copy over the old entries. */
memcpy (new_global, GL(dl_main_searchlist)->r_list,
(GL(dl_main_searchlist)->r_nlist * sizeof (struct link_map *)));
GL(dl_main_searchlist)->r_list = new_global;
}
else if (GL(dl_main_searchlist)->r_nlist + to_add
> GL(dl_global_scope_alloc))
{
/* We have to extend the existing array of link maps in the
main map. */
new_global = (struct link_map **)
realloc (GL(dl_main_searchlist)->r_list,
((GL(dl_global_scope_alloc) + to_add + 8)
* sizeof (struct link_map *)));
if (new_global == NULL)
goto nomem;
GL(dl_global_scope_alloc) += to_add + 8;
GL(dl_main_searchlist)->r_list = new_global;
}
/* Now add the new entries. */
for (cnt = 0; cnt < new->l_searchlist.r_nlist; ++cnt)
{
struct link_map *map = new->l_searchlist.r_list[cnt];
if (map->l_global == 0)
{
map->l_global = 1;
GL(dl_main_searchlist)->r_list[GL(dl_main_searchlist)->r_nlist]
= map;
++GL(dl_main_searchlist)->r_nlist;
}
}
return 0;
}
static void
dl_open_worker (void *a)
{
struct dl_open_args *args = a;
const char *file = args->file;
int mode = args->mode;
struct link_map *new, *l;
const char *dst;
int lazy;
unsigned int i;
/* Maybe we have to expand a DST. */
dst = strchr (file, '$');
if (dst != NULL)
{
const void *caller = args->caller;
size_t len = strlen (file);
size_t required;
struct link_map *call_map;
char *new_file;
/* DSTs must not appear in SUID/SGID programs. */
if (__libc_enable_secure)
/* This is an error. */
_dl_signal_error (0, "dlopen", NULL,
N_("DST not allowed in SUID/SGID programs"));
/* We have to find out from which object the caller is calling. */
call_map = NULL;
for (l = GL(dl_loaded); l; l = l->l_next)
if (caller >= (const void *) l->l_map_start
&& caller < (const void *) l->l_map_end)
{
/* There must be exactly one DSO for the range of the virtual
memory. Otherwise something is really broken. */
call_map = l;
break;
}
if (call_map == NULL)
/* In this case we assume this is the main application. */
call_map = GL(dl_loaded);
/* Determine how much space we need. We have to allocate the
memory locally. */
required = DL_DST_REQUIRED (call_map, file, len, _dl_dst_count (dst, 0));
/* Get space for the new file name. */
new_file = (char *) alloca (required + 1);
/* Generate the new file name. */
_dl_dst_substitute (call_map, file, new_file, 0);
/* If the substitution failed don't try to load. */
if (*new_file == '\0')
_dl_signal_error (0, "dlopen", NULL,
N_("empty dynamic string token substitution"));
/* Now we have a new file name. */
file = new_file;
}
/* Load the named object. */
args->map = new = _dl_map_object (NULL, file, 0, lt_loaded, 0,
mode);
/* If the pointer returned is NULL this means the RTLD_NOLOAD flag is
set and the object is not already loaded. */
if (new == NULL)
{
assert (mode & RTLD_NOLOAD);
return;
}
if (__builtin_expect (mode & __RTLD_SPROF, 0))
/* This happens only if we load a DSO for 'sprof'. */
return;
/* It was already open. */
if (new->l_searchlist.r_list != NULL)
{
/* Let the user know about the opencount. */
if (__builtin_expect (GL(dl_debug_mask) & DL_DEBUG_FILES, 0))
_dl_debug_printf ("opening file=%s; opencount == %u\n\n",
new->l_name, new->l_opencount);
/* If the user requested the object to be in the global namespace
but it is not so far, add it now. */
if ((mode & RTLD_GLOBAL) && new->l_global == 0)
(void) add_to_global (new);
/* Increment just the reference counter of the object. */
++new->l_opencount;
return;
}
/* Load that object's dependencies. */
_dl_map_object_deps (new, NULL, 0, 0);
/* So far, so good. Now check the versions. */
for (i = 0; i < new->l_searchlist.r_nlist; ++i)
if (new->l_searchlist.r_list[i]->l_versions == NULL)
(void) _dl_check_map_versions (new->l_searchlist.r_list[i], 0, 0);
#ifdef SCOPE_DEBUG
show_scope (new);
#endif
/* Only do lazy relocation if `LD_BIND_NOW' is not set. */
lazy = (mode & RTLD_BINDING_MASK) == RTLD_LAZY && GL(dl_lazy);
/* Relocate the objects loaded. We do this in reverse order so that copy
relocs of earlier objects overwrite the data written by later objects. */
l = new;
while (l->l_next)
l = l->l_next;
while (1)
{
if (! l->l_relocated)
{
#ifdef SHARED
if (GL(dl_profile) != NULL)
{
/* If this here is the shared object which we want to profile
make sure the profile is started. We can find out whether
this is necessary or not by observing the `_dl_profile_map'
variable. If was NULL but is not NULL afterwars we must
start the profiling. */
struct link_map *old_profile_map = GL(dl_profile_map);
_dl_relocate_object (l, l->l_scope, 1, 1);
if (old_profile_map == NULL && GL(dl_profile_map) != NULL)
/* We must prepare the profiling. */
_dl_start_profile (GL(dl_profile_map), GL(dl_profile_output));
}
else
#endif
_dl_relocate_object (l, l->l_scope, lazy, 0);
}
if (l == new)
break;
l = l->l_prev;
}
/* Increment the open count for all dependencies. If the file is
not loaded as a dependency here add the search list of the newly
loaded object to the scope. */
for (i = 0; i < new->l_searchlist.r_nlist; ++i)
if (++new->l_searchlist.r_list[i]->l_opencount > 1
&& new->l_searchlist.r_list[i]->l_type == lt_loaded)
{
struct link_map *imap = new->l_searchlist.r_list[i];
struct r_scope_elem **runp = imap->l_scope;
size_t cnt = 0;
while (*runp != NULL)
{
/* This can happen if imap was just loaded, but during
relocation had l_opencount bumped because of relocation
dependency. Avoid duplicates in l_scope. */
if (__builtin_expect (*runp == &new->l_searchlist, 0))
break;
++cnt;
++runp;
}
if (*runp != NULL)
/* Avoid duplicates. */
continue;
if (__builtin_expect (cnt + 1 >= imap->l_scope_max, 0))
{
/* The 'r_scope' array is too small. Allocate a new one
dynamically. */
struct r_scope_elem **newp;
size_t new_size = imap->l_scope_max * 2;
if (imap->l_scope == imap->l_scope_mem)
{
newp = (struct r_scope_elem **)
malloc (new_size * sizeof (struct r_scope_elem *));
if (newp == NULL)
_dl_signal_error (ENOMEM, "dlopen", NULL,
N_("cannot create scope list"));
imap->l_scope = memcpy (newp, imap->l_scope,
cnt * sizeof (imap->l_scope[0]));
}
else
{
newp = (struct r_scope_elem **)
realloc (imap->l_scope,
new_size * sizeof (struct r_scope_elem *));
if (newp == NULL)
_dl_signal_error (ENOMEM, "dlopen", NULL,
N_("cannot create scope list"));
imap->l_scope = newp;
}
imap->l_scope_max = new_size;
}
imap->l_scope[cnt++] = &new->l_searchlist;
imap->l_scope[cnt] = NULL;
}
/* Run the initializer functions of new objects. */
_dl_init (new, __libc_argc, __libc_argv, __environ);
/* Now we can make the new map available in the global scope. */
if (mode & RTLD_GLOBAL)
/* Move the object in the global namespace. */
if (add_to_global (new) != 0)
/* It failed. */
return;
/* Mark the object as not deletable if the RTLD_NODELETE flags was
passed. */
if (__builtin_expect (mode & RTLD_NODELETE, 0))
new->l_flags_1 |= DF_1_NODELETE;
#ifndef SHARED
/* We must be the static _dl_open in libc.a. A static program that
has loaded a dynamic object now has competition. */
__libc_multiple_libcs = 1;
#endif
/* Let the user know about the opencount. */
if (__builtin_expect (GL(dl_debug_mask) & DL_DEBUG_FILES, 0))
_dl_debug_printf ("opening file=%s; opencount == %u\n\n",
new->l_name, new->l_opencount);
}
void *
internal_function
_dl_open (const char *file, int mode, const void *caller)
{
struct dl_open_args args;
const char *objname;
const char *errstring;
int errcode;
if ((mode & RTLD_BINDING_MASK) == 0)
/* One of the flags must be set. */
_dl_signal_error (EINVAL, file, NULL, N_("invalid mode for dlopen()"));
/* Make sure we are alone. */
__libc_lock_lock_recursive (GL(dl_load_lock));
args.file = file;
args.mode = mode;
args.caller = caller;
args.map = NULL;
errcode = _dl_catch_error (&objname, &errstring, dl_open_worker, &args);
#ifndef MAP_COPY
/* We must munmap() the cache file. */
_dl_unload_cache ();
#endif
/* Release the lock. */
__libc_lock_unlock_recursive (GL(dl_load_lock));
if (errstring)
{
/* Some error occurred during loading. */
char *local_errstring;
size_t len_errstring;
/* Remove the object from memory. It may be in an inconsistent
state if relocation failed, for example. */
if (args.map)
{
unsigned int i;
/* Increment open counters for all objects since this has
not happened yet. */
for (i = 0; i < args.map->l_searchlist.r_nlist; ++i)
++args.map->l_searchlist.r_list[i]->l_opencount;
_dl_close (args.map);
}
/* Make a local copy of the error string so that we can release the
memory allocated for it. */
len_errstring = strlen (errstring) + 1;
if (objname == errstring + len_errstring)
{
size_t total_len = len_errstring + strlen (objname) + 1;
local_errstring = alloca (total_len);
memcpy (local_errstring, errstring, total_len);
objname = local_errstring + len_errstring;
}
else
{
local_errstring = alloca (len_errstring);
memcpy (local_errstring, errstring, len_errstring);
}
if (errstring != _dl_out_of_memory)
free ((char *) errstring);
/* Reraise the error. */
_dl_signal_error (errcode, objname, NULL, local_errstring);
}
#ifndef SHARED
DL_STATIC_INIT (args.map);
#endif
return args.map;
}
#ifdef SCOPE_DEBUG
#include <unistd.h>
static void
show_scope (struct link_map *new)
{
int scope_cnt;
for (scope_cnt = 0; new->l_scope[scope_cnt] != NULL; ++scope_cnt)
{
char numbuf[2];
unsigned int cnt;
numbuf[0] = '0' + scope_cnt;
numbuf[1] = '\0';
_dl_printf ("scope %s:", numbuf);
for (cnt = 0; cnt < new->l_scope[scope_cnt]->r_nlist; ++cnt)
if (*new->l_scope[scope_cnt]->r_list[cnt]->l_name)
_dl_printf (" %s", new->l_scope[scope_cnt]->r_list[cnt]->l_name);
else
_dl_printf (" <main>");
_dl_printf ("\n");
}
}
#endif