glibc/elf/dl-sym.c
Paul Eggert 5a82c74822 Prefer https to http for gnu.org and fsf.org URLs
Also, change sources.redhat.com to sourceware.org.
This patch was automatically generated by running the following shell
script, which uses GNU sed, and which avoids modifying files imported
from upstream:

sed -ri '
  s,(http|ftp)(://(.*\.)?(gnu|fsf|sourceware)\.org($|[^.]|\.[^a-z])),https\2,g
  s,(http|ftp)(://(.*\.)?)sources\.redhat\.com($|[^.]|\.[^a-z]),https\2sourceware.org\4,g
' \
  $(find $(git ls-files) -prune -type f \
      ! -name '*.po' \
      ! -name 'ChangeLog*' \
      ! -path COPYING ! -path COPYING.LIB \
      ! -path manual/fdl-1.3.texi ! -path manual/lgpl-2.1.texi \
      ! -path manual/texinfo.tex ! -path scripts/config.guess \
      ! -path scripts/config.sub ! -path scripts/install-sh \
      ! -path scripts/mkinstalldirs ! -path scripts/move-if-change \
      ! -path INSTALL ! -path  locale/programs/charmap-kw.h \
      ! -path po/libc.pot ! -path sysdeps/gnu/errlist.c \
      ! '(' -name configure \
            -execdir test -f configure.ac -o -f configure.in ';' ')' \
      ! '(' -name preconfigure \
            -execdir test -f preconfigure.ac ';' ')' \
      -print)

and then by running 'make dist-prepare' to regenerate files built
from the altered files, and then executing the following to cleanup:

  chmod a+x sysdeps/unix/sysv/linux/riscv/configure
  # Omit irrelevant whitespace and comment-only changes,
  # perhaps from a slightly-different Autoconf version.
  git checkout -f \
    sysdeps/csky/configure \
    sysdeps/hppa/configure \
    sysdeps/riscv/configure \
    sysdeps/unix/sysv/linux/csky/configure
  # Omit changes that caused a pre-commit check to fail like this:
  # remote: *** error: sysdeps/powerpc/powerpc64/ppc-mcount.S: trailing lines
  git checkout -f \
    sysdeps/powerpc/powerpc64/ppc-mcount.S \
    sysdeps/unix/sysv/linux/s390/s390-64/syscall.S
  # Omit change that caused a pre-commit check to fail like this:
  # remote: *** error: sysdeps/sparc/sparc64/multiarch/memcpy-ultra3.S: last line does not end in newline
  git checkout -f sysdeps/sparc/sparc64/multiarch/memcpy-ultra3.S
2019-09-07 02:43:31 -07:00

256 lines
6.9 KiB
C

/* Look up a symbol in a shared object loaded by `dlopen'.
Copyright (C) 1999-2019 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, see
<https://www.gnu.org/licenses/>. */
#include <assert.h>
#include <stddef.h>
#include <setjmp.h>
#include <stdlib.h>
#include <libintl.h>
#include <dlfcn.h>
#include <ldsodefs.h>
#include <dl-hash.h>
#include <sysdep-cancel.h>
#include <dl-tls.h>
#include <dl-irel.h>
#ifdef SHARED
/* Systems which do not have tls_index also probably have to define
DONT_USE_TLS_INDEX. */
# ifndef __TLS_GET_ADDR
# define __TLS_GET_ADDR __tls_get_addr
# endif
/* Return the symbol address given the map of the module it is in and
the symbol record. This is used in dl-sym.c. */
static void *
_dl_tls_symaddr (struct link_map *map, const ElfW(Sym) *ref)
{
# ifndef DONT_USE_TLS_INDEX
tls_index tmp =
{
.ti_module = map->l_tls_modid,
.ti_offset = ref->st_value
};
return __TLS_GET_ADDR (&tmp);
# else
return __TLS_GET_ADDR (map->l_tls_modid, ref->st_value);
# endif
}
#endif
struct call_dl_lookup_args
{
/* Arguments to do_dlsym. */
struct link_map *map;
const char *name;
struct r_found_version *vers;
int flags;
/* Return values of do_dlsym. */
lookup_t loadbase;
const ElfW(Sym) **refp;
};
static void
call_dl_lookup (void *ptr)
{
struct call_dl_lookup_args *args = (struct call_dl_lookup_args *) ptr;
args->map = GLRO(dl_lookup_symbol_x) (args->name, args->map, args->refp,
args->map->l_scope, args->vers, 0,
args->flags, NULL);
}
static void *
do_sym (void *handle, const char *name, void *who,
struct r_found_version *vers, int flags)
{
const ElfW(Sym) *ref = NULL;
lookup_t result;
ElfW(Addr) caller = (ElfW(Addr)) who;
struct link_map *l = _dl_find_dso_for_object (caller);
/* If the address is not recognized the call comes from the main
program (we hope). */
struct link_map *match = l ? l : GL(dl_ns)[LM_ID_BASE]._ns_loaded;
if (handle == RTLD_DEFAULT)
{
/* Search the global scope. We have the simple case where
we look up in the scope of an object which was part of
the initial binary. And then the more complex part
where the object is dynamically loaded and the scope
array can change. */
if (RTLD_SINGLE_THREAD_P)
result = GLRO(dl_lookup_symbol_x) (name, match, &ref,
match->l_scope, vers, 0,
flags | DL_LOOKUP_ADD_DEPENDENCY,
NULL);
else
{
struct call_dl_lookup_args args;
args.name = name;
args.map = match;
args.vers = vers;
args.flags
= flags | DL_LOOKUP_ADD_DEPENDENCY | DL_LOOKUP_GSCOPE_LOCK;
args.refp = &ref;
THREAD_GSCOPE_SET_FLAG ();
struct dl_exception exception;
int err = _dl_catch_exception (&exception, call_dl_lookup, &args);
THREAD_GSCOPE_RESET_FLAG ();
if (__glibc_unlikely (exception.errstring != NULL))
_dl_signal_exception (err, &exception, NULL);
result = args.map;
}
}
else if (handle == RTLD_NEXT)
{
if (__glibc_unlikely (match == GL(dl_ns)[LM_ID_BASE]._ns_loaded))
{
if (match == NULL
|| caller < match->l_map_start
|| caller >= match->l_map_end)
_dl_signal_error (0, NULL, NULL, N_("\
RTLD_NEXT used in code not dynamically loaded"));
}
struct link_map *l = match;
while (l->l_loader != NULL)
l = l->l_loader;
result = GLRO(dl_lookup_symbol_x) (name, match, &ref, l->l_local_scope,
vers, 0, 0, match);
}
else
{
/* Search the scope of the given object. */
struct link_map *map = handle;
result = GLRO(dl_lookup_symbol_x) (name, map, &ref, map->l_local_scope,
vers, 0, flags, NULL);
}
if (ref != NULL)
{
void *value;
#ifdef SHARED
if (ELFW(ST_TYPE) (ref->st_info) == STT_TLS)
/* The found symbol is a thread-local storage variable.
Return the address for to the current thread. */
value = _dl_tls_symaddr (result, ref);
else
#endif
value = DL_SYMBOL_ADDRESS (result, ref);
/* Resolve indirect function address. */
if (__glibc_unlikely (ELFW(ST_TYPE) (ref->st_info) == STT_GNU_IFUNC))
{
DL_FIXUP_VALUE_TYPE fixup
= DL_FIXUP_MAKE_VALUE (result, (ElfW(Addr)) value);
fixup = elf_ifunc_invoke (DL_FIXUP_VALUE_ADDR (fixup));
value = (void *) DL_FIXUP_VALUE_CODE_ADDR (fixup);
}
#ifdef SHARED
/* Auditing checkpoint: we have a new binding. Provide the
auditing libraries the possibility to change the value and
tell us whether further auditing is wanted. */
if (__glibc_unlikely (GLRO(dl_naudit) > 0))
{
const char *strtab = (const char *) D_PTR (result,
l_info[DT_STRTAB]);
/* Compute index of the symbol entry in the symbol table of
the DSO with the definition. */
unsigned int ndx = (ref - (ElfW(Sym) *) D_PTR (result,
l_info[DT_SYMTAB]));
if ((match->l_audit_any_plt | result->l_audit_any_plt) != 0)
{
unsigned int altvalue = 0;
struct audit_ifaces *afct = GLRO(dl_audit);
/* Synthesize a symbol record where the st_value field is
the result. */
ElfW(Sym) sym = *ref;
sym.st_value = (ElfW(Addr)) value;
for (unsigned int cnt = 0; cnt < GLRO(dl_naudit); ++cnt)
{
if (afct->symbind != NULL
&& ((match->l_audit[cnt].bindflags & LA_FLG_BINDFROM)
!= 0
|| ((result->l_audit[cnt].bindflags & LA_FLG_BINDTO)
!= 0)))
{
unsigned int flags = altvalue | LA_SYMB_DLSYM;
uintptr_t new_value
= afct->symbind (&sym, ndx,
&match->l_audit[cnt].cookie,
&result->l_audit[cnt].cookie,
&flags, strtab + ref->st_name);
if (new_value != (uintptr_t) sym.st_value)
{
altvalue = LA_SYMB_ALTVALUE;
sym.st_value = new_value;
}
}
afct = afct->next;
}
value = (void *) sym.st_value;
}
}
#endif
return value;
}
return NULL;
}
void *
_dl_vsym (void *handle, const char *name, const char *version, void *who)
{
struct r_found_version vers;
/* Compute hash value to the version string. */
vers.name = version;
vers.hidden = 1;
vers.hash = _dl_elf_hash (version);
/* We don't have a specific file where the symbol can be found. */
vers.filename = NULL;
return do_sym (handle, name, who, &vers, 0);
}
void *
_dl_sym (void *handle, const char *name, void *who)
{
return do_sym (handle, name, who, NULL, DL_LOOKUP_RETURN_NEWEST);
}