glibc/elf/dl-support.c

314 lines
8.0 KiB
C

/* Support for dynamic linking code in static libc.
Copyright (C) 1996-2002, 2003, 2004 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. */
/* This file defines some things that for the dynamic linker are defined in
rtld.c and dl-sysdep.c in ways appropriate to bootstrap dynamic linking. */
#include <errno.h>
#include <libintl.h>
#include <stdlib.h>
#include <unistd.h>
#include <ldsodefs.h>
#include <dl-machine.h>
#include <bits/libc-lock.h>
#include <dl-cache.h>
#include <dl-librecon.h>
#include <unsecvars.h>
#include <hp-timing.h>
extern char *__progname;
char **_dl_argv = &__progname; /* This is checked for some error messages. */
/* Name of the architecture. */
const char *_dl_platform;
size_t _dl_platformlen;
int _dl_debug_mask;
int _dl_lazy;
ElfW(Addr) _dl_use_load_bias = -2;
int _dl_dynamic_weak;
/* If nonzero print warnings about problematic situations. */
int _dl_verbose;
/* We never do profiling. */
const char *_dl_profile;
const char *_dl_profile_output;
/* Names of shared object for which the RUNPATHs and RPATHs should be
ignored. */
const char *_dl_inhibit_rpath;
/* The map for the object we will profile. */
struct link_map *_dl_profile_map;
/* This is the address of the last stack address ever used. */
void *__libc_stack_end;
/* Path where the binary is found. */
const char *_dl_origin_path;
/* Nonzero if runtime lookup should not update the .got/.plt. */
int _dl_bind_not;
/* Namespace information. */
struct link_namespaces _dl_ns[DL_NNS];
/* Incremented whenever something may have been added to dl_loaded. */
unsigned long long _dl_load_adds;
/* Fake scope. In dynamically linked binaries this is the scope of the
main application but here we don't have something like this. So
create a fake scope containing nothing. */
struct r_scope_elem _dl_initial_searchlist;
#ifndef HAVE_INLINED_SYSCALLS
/* Nonzero during startup. */
int _dl_starting_up = 1;
#endif
/* Get architecture specific initializer. */
#include <dl-procinfo.c>
/* We expect less than a second for relocation. */
#ifdef HP_SMALL_TIMING_AVAIL
# undef HP_TIMING_AVAIL
# define HP_TIMING_AVAIL HP_SMALL_TIMING_AVAIL
#endif
/* Initial value of the CPU clock. */
#ifndef HP_TIMING_NONAVAIL
hp_timing_t _dl_cpuclock_offset;
#endif
#ifdef USE_TLS
void (*_dl_init_static_tls) (struct link_map *) = &_dl_nothread_init_static_tls;
#endif
size_t _dl_pagesize;
unsigned int _dl_osversion;
/* All known directories in sorted order. */
struct r_search_path_elem *_dl_all_dirs;
/* All directories after startup. */
struct r_search_path_elem *_dl_init_all_dirs;
/* The object to be initialized first. */
struct link_map *_dl_initfirst;
/* Descriptor to write debug messages to. */
int _dl_debug_fd = STDERR_FILENO;
int _dl_correct_cache_id = _DL_CACHE_DEFAULT_ID;
ElfW(Phdr) *_dl_phdr;
size_t _dl_phnum;
unsigned long int _dl_hwcap __attribute__ ((nocommon));
/* Prevailing state of the stack, PF_X indicating it's executable. */
ElfW(Word) _dl_stack_flags = PF_R|PF_W|PF_X;
/* If loading a shared object requires that we make the stack executable
when it was not, we do it by calling this function.
It returns an errno code or zero on success. */
int (*_dl_make_stack_executable_hook) (void **) internal_function
= _dl_make_stack_executable;
#ifdef NEED_DL_SYSINFO
/* Needed for improved syscall handling on at least x86/Linux. */
uintptr_t _dl_sysinfo = DL_SYSINFO_DEFAULT;
#endif
#if defined NEED_DL_SYSINFO || defined NEED_DL_SYSINFO_DSO
/* Address of the ELF headers in the vsyscall page. */
const ElfW(Ehdr) *_dl_sysinfo_dso;
#endif
/* During the program run we must not modify the global data of
loaded shared object simultanously in two threads. Therefore we
protect `_dl_open' and `_dl_close' in dl-close.c.
This must be a recursive lock since the initializer function of
the loaded object might as well require a call to this function.
At this time it is not anymore a problem to modify the tables. */
__rtld_lock_define_initialized_recursive (, _dl_load_lock)
#ifdef HAVE_AUX_VECTOR
int _dl_clktck;
void
internal_function
_dl_aux_init (ElfW(auxv_t) *av)
{
int seen = 0;
uid_t uid = 0;
gid_t gid = 0;
for (; av->a_type != AT_NULL; ++av)
switch (av->a_type)
{
case AT_PAGESZ:
GLRO(dl_pagesize) = av->a_un.a_val;
break;
case AT_CLKTCK:
GLRO(dl_clktck) = av->a_un.a_val;
break;
case AT_PHDR:
GL(dl_phdr) = av->a_un.a_ptr;
break;
case AT_PHNUM:
GL(dl_phnum) = av->a_un.a_val;
break;
case AT_HWCAP:
GLRO(dl_hwcap) = av->a_un.a_val;
break;
#ifdef NEED_DL_SYSINFO
case AT_SYSINFO:
GL(dl_sysinfo) = av->a_un.a_val;
break;
#endif
#if defined NEED_DL_SYSINFO || defined NEED_DL_SYSINFO_DSO
case AT_SYSINFO_EHDR:
GL(dl_sysinfo_dso) = av->a_un.a_ptr;
break;
#endif
case AT_UID:
uid ^= av->a_un.a_val;
seen |= 1;
break;
case AT_EUID:
uid ^= av->a_un.a_val;
seen |= 2;
break;
case AT_GID:
gid ^= av->a_un.a_val;
seen |= 4;
break;
case AT_EGID:
gid ^= av->a_un.a_val;
seen |= 8;
break;
case AT_SECURE:
seen = -1;
__libc_enable_secure = av->a_un.a_val;
__libc_enable_secure_decided = 1;
break;
}
if (seen == 0xf)
{
__libc_enable_secure = uid != 0 || gid != 0;
__libc_enable_secure_decided = 1;
}
}
#endif
void
internal_function
_dl_non_dynamic_init (void)
{
if (HP_TIMING_AVAIL)
HP_TIMING_NOW (_dl_cpuclock_offset);
if (!_dl_pagesize)
_dl_pagesize = __getpagesize ();
_dl_verbose = *(getenv ("LD_WARN") ?: "") == '\0' ? 0 : 1;
/* Initialize the data structures for the search paths for shared
objects. */
_dl_init_paths (getenv ("LD_LIBRARY_PATH"));
_dl_lazy = *(getenv ("LD_BIND_NOW") ?: "") == '\0';
_dl_bind_not = *(getenv ("LD_BIND_NOT") ?: "") != '\0';
_dl_dynamic_weak = *(getenv ("LD_DYNAMIC_WEAK") ?: "") == '\0';
_dl_profile_output = getenv ("LD_PROFILE_OUTPUT");
if (_dl_profile_output == NULL || _dl_profile_output[0] == '\0')
_dl_profile_output
= &"/var/tmp\0/var/profile"[__libc_enable_secure ? 9 : 0];
if (__libc_enable_secure)
{
static const char unsecure_envvars[] =
UNSECURE_ENVVARS
#ifdef EXTRA_UNSECURE_ENVVARS
EXTRA_UNSECURE_ENVVARS
#endif
;
const char *cp = unsecure_envvars;
while (cp < unsecure_envvars + sizeof (unsecure_envvars))
{
__unsetenv (cp);
cp = (const char *) __rawmemchr (cp, '\0') + 1;
}
if (__access ("/etc/suid-debug", F_OK) != 0)
__unsetenv ("MALLOC_CHECK_");
}
#ifdef DL_PLATFORM_INIT
DL_PLATFORM_INIT;
#endif
#ifdef DL_OSVERSION_INIT
DL_OSVERSION_INIT;
#endif
/* Now determine the length of the platform string. */
if (_dl_platform != NULL)
_dl_platformlen = strlen (_dl_platform);
/* Scan for a program header telling us the stack is nonexecutable. */
if (_dl_phdr != NULL)
for (uint_fast16_t i = 0; i < _dl_phnum; ++i)
if (_dl_phdr[i].p_type == PT_GNU_STACK)
{
_dl_stack_flags = _dl_phdr[i].p_flags;
break;
}
}
const struct r_strlenpair *
internal_function
_dl_important_hwcaps (const char *platform, size_t platform_len, size_t *sz,
size_t *max_capstrlen)
{
static struct r_strlenpair result;
static char buf[1];
result.str = buf; /* Does not really matter. */
result.len = 0;
*sz = 1;
return &result;
}
#ifdef DL_SYSINFO_IMPLEMENTATION
DL_SYSINFO_IMPLEMENTATION
#endif