2021-02-25 19:10:57 +08:00
|
|
|
/* Perform initialization and invoke main.
|
2023-01-07 05:08:04 +08:00
|
|
|
Copyright (C) 1998-2023 Free Software Foundation, Inc.
|
1998-03-07 01:21:43 +08:00
|
|
|
This file is part of the GNU C Library.
|
|
|
|
|
|
|
|
The GNU C Library is free software; you can redistribute it and/or
|
2001-07-06 12:58:11 +08:00
|
|
|
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.
|
1998-03-07 01:21:43 +08:00
|
|
|
|
|
|
|
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
|
2001-07-06 12:58:11 +08:00
|
|
|
Lesser General Public License for more details.
|
1998-03-07 01:21:43 +08:00
|
|
|
|
2001-07-06 12:58:11 +08:00
|
|
|
You should have received a copy of the GNU Lesser General Public
|
2012-02-10 07:18:22 +08:00
|
|
|
License along with the GNU C Library; if not, see
|
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 13:40:42 +08:00
|
|
|
<https://www.gnu.org/licenses/>. */
|
1998-03-07 01:21:43 +08:00
|
|
|
|
2021-02-25 19:10:57 +08:00
|
|
|
/* Note: This code is only part of the startup code proper for
|
|
|
|
statically linked binaries. For dynamically linked binaries, it
|
|
|
|
resides in libc.so. */
|
|
|
|
|
2021-01-15 20:49:24 +08:00
|
|
|
/* Mark symbols hidden in static PIE for early self relocation to work. */
|
|
|
|
#if BUILD_PIE_DEFAULT
|
|
|
|
# pragma GCC visibility push(hidden)
|
|
|
|
#endif
|
2021-02-25 19:10:57 +08:00
|
|
|
|
2013-03-29 07:15:48 +08:00
|
|
|
#include <assert.h>
|
1998-03-08 23:26:29 +08:00
|
|
|
#include <stdlib.h>
|
2002-12-02 06:14:57 +08:00
|
|
|
#include <stdio.h>
|
1998-03-08 23:26:29 +08:00
|
|
|
#include <unistd.h>
|
2000-03-24 04:31:46 +08:00
|
|
|
#include <ldsodefs.h>
|
2020-10-31 05:38:31 +08:00
|
|
|
#include <libc-diag.h>
|
2017-01-01 02:02:17 +08:00
|
|
|
#include <libc-internal.h>
|
elf: Implement __libc_early_init
This function is defined in libc.so, and the dynamic loader calls
right after relocation has been finished, before any ELF constructors
or the preinit function is invoked. It is also used in the static
build for initializing parts of the static libc.
To locate __libc_early_init, a direct symbol lookup function is used,
_dl_lookup_direct. It does not search the entire symbol scope and
consults merely a single link map. This function could also be used
to implement lookups in the vDSO (as an optimization).
A per-namespace variable (libc_map) is added for locating libc.so,
to avoid repeated traversals of the search scope. It is similar to
GL(dl_initfirst). An alternative would have been to thread a context
argument from _dl_open down to _dl_map_object_from_fd (where libc.so
is identified). This could have avoided the global variable, but
the change would be larger as a result. It would not have been
possible to use this to replace GL(dl_initfirst) because that global
variable is used to pass the function pointer past the stack switch
from dl_main to the main program. Replacing that requires adding
a new argument to _dl_init, which in turn needs changes to the
architecture-specific libc.so startup code written in assembler.
__libc_early_init should not be used to replace _dl_var_init (as
it exists today on some architectures). Instead, _dl_lookup_direct
should be used to look up a new variable symbol in libc.so, and
that should then be initialized from the dynamic loader, immediately
after the object has been loaded in _dl_map_object_from_fd (before
relocation is run). This way, more IFUNC resolvers which depend on
these variables will work.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
2020-04-25 04:31:15 +08:00
|
|
|
#include <elf/libc-early-init.h>
|
2020-04-29 21:44:03 +08:00
|
|
|
#include <stdbool.h>
|
2021-02-25 19:10:57 +08:00
|
|
|
#include <elf-initfini.h>
|
|
|
|
#include <shlib-compat.h>
|
2017-01-01 02:02:17 +08:00
|
|
|
|
|
|
|
#include <elf/dl-tunables.h>
|
1998-03-08 23:26:29 +08:00
|
|
|
|
1998-03-18 22:42:25 +08:00
|
|
|
extern void __libc_init_first (int argc, char **argv, char **envp);
|
|
|
|
|
2002-09-15 10:37:32 +08:00
|
|
|
#include <tls.h>
|
2000-07-07 05:16:06 +08:00
|
|
|
#ifndef SHARED
|
2002-12-02 06:14:57 +08:00
|
|
|
# include <dl-osinfo.h>
|
2005-06-27 02:14:26 +08:00
|
|
|
# ifndef THREAD_SET_STACK_GUARD
|
|
|
|
/* Only exported for architectures that don't store the stack guard canary
|
|
|
|
in thread local area. */
|
|
|
|
uintptr_t __stack_chk_guard attribute_relro;
|
|
|
|
# endif
|
2013-09-23 12:52:09 +08:00
|
|
|
# ifndef THREAD_SET_POINTER_GUARD
|
|
|
|
/* Only exported for architectures that don't store the pointer guard
|
|
|
|
value in thread local area. */
|
2021-07-10 02:09:14 +08:00
|
|
|
uintptr_t __pointer_chk_guard_local attribute_relro attribute_hidden;
|
2013-09-23 12:52:09 +08:00
|
|
|
# endif
|
2000-07-07 05:16:06 +08:00
|
|
|
#endif
|
|
|
|
|
2012-08-22 06:01:27 +08:00
|
|
|
#ifndef SHARED
|
|
|
|
# include <link.h>
|
|
|
|
# include <dl-irel.h>
|
|
|
|
|
|
|
|
# ifdef ELF_MACHINE_IRELA
|
|
|
|
# define IREL_T ElfW(Rela)
|
|
|
|
# define IPLT_START __rela_iplt_start
|
|
|
|
# define IPLT_END __rela_iplt_end
|
|
|
|
# define IREL elf_irela
|
|
|
|
# elif defined ELF_MACHINE_IREL
|
|
|
|
# define IREL_T ElfW(Rel)
|
|
|
|
# define IPLT_START __rel_iplt_start
|
|
|
|
# define IPLT_END __rel_iplt_end
|
|
|
|
# define IREL elf_irel
|
|
|
|
# endif
|
|
|
|
|
|
|
|
static void
|
|
|
|
apply_irel (void)
|
|
|
|
{
|
2012-08-23 03:53:38 +08:00
|
|
|
# ifdef IREL
|
|
|
|
/* We use weak references for these so that we'll still work with a linker
|
|
|
|
that doesn't define them. Such a linker doesn't support IFUNC at all
|
|
|
|
and so uses won't work, but a statically-linked program that doesn't
|
|
|
|
use any IFUNC symbols won't have a problem. */
|
|
|
|
extern const IREL_T IPLT_START[] __attribute__ ((weak));
|
|
|
|
extern const IREL_T IPLT_END[] __attribute__ ((weak));
|
2012-08-22 06:01:27 +08:00
|
|
|
for (const IREL_T *ipltent = IPLT_START; ipltent < IPLT_END; ++ipltent)
|
|
|
|
IREL (ipltent);
|
2012-08-23 03:53:38 +08:00
|
|
|
# endif
|
2012-08-22 06:01:27 +08:00
|
|
|
}
|
|
|
|
#endif
|
|
|
|
|
|
|
|
|
2003-03-16 07:09:11 +08:00
|
|
|
#ifdef LIBC_START_MAIN
|
2004-02-20 14:07:55 +08:00
|
|
|
# ifdef LIBC_START_DISABLE_INLINE
|
|
|
|
# define STATIC static
|
|
|
|
# else
|
|
|
|
# define STATIC static inline __attribute__ ((always_inline))
|
|
|
|
# endif
|
2021-02-25 19:10:57 +08:00
|
|
|
# define DO_DEFINE_LIBC_START_MAIN_VERSION 0
|
2003-03-16 07:09:11 +08:00
|
|
|
#else
|
|
|
|
# define STATIC
|
2021-02-25 19:10:57 +08:00
|
|
|
# define LIBC_START_MAIN __libc_start_main_impl
|
|
|
|
# define DO_DEFINE_LIBC_START_MAIN_VERSION 1
|
2003-03-16 07:09:11 +08:00
|
|
|
#endif
|
|
|
|
|
|
|
|
#ifdef MAIN_AUXVEC_ARG
|
2003-04-12 08:58:26 +08:00
|
|
|
/* main gets passed a pointer to the auxiliary. */
|
|
|
|
# define MAIN_AUXVEC_DECL , void *
|
|
|
|
# define MAIN_AUXVEC_PARAM , auxvec
|
|
|
|
#else
|
|
|
|
# define MAIN_AUXVEC_DECL
|
|
|
|
# define MAIN_AUXVEC_PARAM
|
2003-03-16 07:09:11 +08:00
|
|
|
#endif
|
|
|
|
|
2017-05-31 09:08:32 +08:00
|
|
|
#ifndef ARCH_INIT_CPU_FEATURES
|
|
|
|
# define ARCH_INIT_CPU_FEATURES()
|
|
|
|
#endif
|
|
|
|
|
2021-04-22 01:49:50 +08:00
|
|
|
/* Obtain the definition of __libc_start_call_main. */
|
|
|
|
#include <libc_start_call_main.h>
|
|
|
|
|
2021-02-25 19:10:57 +08:00
|
|
|
#ifdef SHARED
|
|
|
|
/* Initialization for dynamic executables. Find the main executable
|
|
|
|
link map and run its init functions. */
|
|
|
|
static void
|
|
|
|
call_init (int argc, char **argv, char **env)
|
|
|
|
{
|
|
|
|
/* Obtain the main map of the executable. */
|
|
|
|
struct link_map *l = GL(dl_ns)[LM_ID_BASE]._ns_loaded;
|
|
|
|
|
|
|
|
/* DT_PREINIT_ARRAY is not processed here. It is already handled in
|
|
|
|
_dl_init in elf/dl-init.c. Also see the call_init function in
|
|
|
|
the same file. */
|
|
|
|
|
|
|
|
if (ELF_INITFINI && l->l_info[DT_INIT] != NULL)
|
|
|
|
DL_CALL_DT_INIT(l, l->l_addr + l->l_info[DT_INIT]->d_un.d_ptr,
|
|
|
|
argc, argv, env);
|
|
|
|
|
|
|
|
ElfW(Dyn) *init_array = l->l_info[DT_INIT_ARRAY];
|
|
|
|
if (init_array != NULL)
|
|
|
|
{
|
|
|
|
unsigned int jm
|
|
|
|
= l->l_info[DT_INIT_ARRAYSZ]->d_un.d_val / sizeof (ElfW(Addr));
|
|
|
|
ElfW(Addr) *addrs = (void *) (init_array->d_un.d_ptr + l->l_addr);
|
|
|
|
for (unsigned int j = 0; j < jm; ++j)
|
|
|
|
((dl_init_t) addrs[j]) (argc, argv, env);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
#else /* !SHARED */
|
|
|
|
|
|
|
|
/* These magic symbols are provided by the linker. */
|
|
|
|
extern void (*__preinit_array_start []) (int, char **, char **)
|
|
|
|
attribute_hidden;
|
|
|
|
extern void (*__preinit_array_end []) (int, char **, char **)
|
|
|
|
attribute_hidden;
|
|
|
|
extern void (*__init_array_start []) (int, char **, char **)
|
|
|
|
attribute_hidden;
|
|
|
|
extern void (*__init_array_end []) (int, char **, char **)
|
|
|
|
attribute_hidden;
|
|
|
|
extern void (*__fini_array_start []) (void) attribute_hidden;
|
|
|
|
extern void (*__fini_array_end []) (void) attribute_hidden;
|
|
|
|
|
|
|
|
# if ELF_INITFINI
|
|
|
|
/* These function symbols are provided for the .init/.fini section entry
|
|
|
|
points automagically by the linker. */
|
|
|
|
extern void _init (void);
|
|
|
|
extern void _fini (void);
|
|
|
|
# endif
|
|
|
|
|
|
|
|
/* Initialization for static executables. There is no dynamic
|
|
|
|
segment, so we access the symbols directly. */
|
|
|
|
static void
|
|
|
|
call_init (int argc, char **argv, char **envp)
|
|
|
|
{
|
|
|
|
/* For static executables, preinit happens right before init. */
|
|
|
|
{
|
|
|
|
const size_t size = __preinit_array_end - __preinit_array_start;
|
|
|
|
size_t i;
|
|
|
|
for (i = 0; i < size; i++)
|
|
|
|
(*__preinit_array_start [i]) (argc, argv, envp);
|
|
|
|
}
|
|
|
|
|
|
|
|
# if ELF_INITFINI
|
|
|
|
_init ();
|
|
|
|
# endif
|
|
|
|
|
|
|
|
const size_t size = __init_array_end - __init_array_start;
|
|
|
|
for (size_t i = 0; i < size; i++)
|
|
|
|
(*__init_array_start [i]) (argc, argv, envp);
|
|
|
|
}
|
|
|
|
|
|
|
|
/* Likewise for the destructor. */
|
|
|
|
static void
|
|
|
|
call_fini (void *unused)
|
|
|
|
{
|
|
|
|
size_t i = __fini_array_end - __fini_array_start;
|
|
|
|
while (i-- > 0)
|
|
|
|
(*__fini_array_start [i]) ();
|
|
|
|
|
|
|
|
# if ELF_INITFINI
|
|
|
|
_fini ();
|
|
|
|
# endif
|
|
|
|
}
|
|
|
|
|
|
|
|
#endif /* !SHARED */
|
|
|
|
|
2017-07-18 04:48:59 +08:00
|
|
|
#include <libc-start.h>
|
|
|
|
|
2003-04-12 08:58:26 +08:00
|
|
|
STATIC int LIBC_START_MAIN (int (*main) (int, char **, char **
|
|
|
|
MAIN_AUXVEC_DECL),
|
2003-03-16 07:09:11 +08:00
|
|
|
int argc,
|
2013-02-14 07:30:40 +08:00
|
|
|
char **argv,
|
2003-03-16 07:09:11 +08:00
|
|
|
#ifdef LIBC_START_MAIN_AUXVEC_ARG
|
2013-02-14 07:30:40 +08:00
|
|
|
ElfW(auxv_t) *auxvec,
|
2003-03-16 07:09:11 +08:00
|
|
|
#endif
|
|
|
|
__typeof (main) init,
|
|
|
|
void (*fini) (void),
|
|
|
|
void (*rtld_fini) (void),
|
2013-02-14 07:30:40 +08:00
|
|
|
void *stack_end)
|
2000-11-20 17:16:41 +08:00
|
|
|
__attribute__ ((noreturn));
|
1999-07-10 00:18:17 +08:00
|
|
|
|
2005-01-07 06:40:27 +08:00
|
|
|
|
2021-02-25 19:10:57 +08:00
|
|
|
/* Note: The init and fini parameters are no longer used. fini is
|
|
|
|
completely unused, init is still called if not NULL, but the
|
|
|
|
current startup code always passes NULL. (In the future, it would
|
|
|
|
be possible to use fini to pass a version code if init is NULL, to
|
|
|
|
indicate the link-time glibc without introducing a hard
|
|
|
|
incompatibility for new programs with older glibc versions.)
|
|
|
|
|
|
|
|
For dynamically linked executables, the dynamic segment is used to
|
|
|
|
locate constructors and destructors. For statically linked
|
|
|
|
executables, the relevant symbols are access directly. */
|
2003-03-16 07:09:11 +08:00
|
|
|
STATIC int
|
2003-04-12 08:58:26 +08:00
|
|
|
LIBC_START_MAIN (int (*main) (int, char **, char ** MAIN_AUXVEC_DECL),
|
2013-02-14 07:30:40 +08:00
|
|
|
int argc, char **argv,
|
2003-03-16 07:09:11 +08:00
|
|
|
#ifdef LIBC_START_MAIN_AUXVEC_ARG
|
2013-02-14 07:30:40 +08:00
|
|
|
ElfW(auxv_t) *auxvec,
|
2003-03-16 07:09:11 +08:00
|
|
|
#endif
|
|
|
|
__typeof (main) init,
|
|
|
|
void (*fini) (void),
|
2013-02-14 07:30:40 +08:00
|
|
|
void (*rtld_fini) (void), void *stack_end)
|
1998-03-07 01:21:43 +08:00
|
|
|
{
|
2005-01-04 15:11:05 +08:00
|
|
|
#ifndef SHARED
|
2013-02-14 07:30:40 +08:00
|
|
|
char **ev = &argv[argc + 1];
|
2005-02-16 17:39:23 +08:00
|
|
|
|
2013-02-14 07:30:40 +08:00
|
|
|
__environ = ev;
|
2000-06-13 15:33:12 +08:00
|
|
|
|
2004-01-14 08:24:36 +08:00
|
|
|
/* Store the lowest stack address. This is done in ld.so if this is
|
|
|
|
the code for the DSO. */
|
1998-06-07 22:06:56 +08:00
|
|
|
__libc_stack_end = stack_end;
|
1998-03-18 22:42:25 +08:00
|
|
|
|
2002-07-24 07:12:01 +08:00
|
|
|
# ifdef HAVE_AUX_VECTOR
|
|
|
|
/* First process the auxiliary vector since we need to find the
|
|
|
|
program header to locate an eventually present PT_TLS entry. */
|
2003-03-16 07:09:11 +08:00
|
|
|
# ifndef LIBC_START_MAIN_AUXVEC_ARG
|
2013-02-14 07:30:40 +08:00
|
|
|
ElfW(auxv_t) *auxvec;
|
2003-03-16 07:09:11 +08:00
|
|
|
{
|
2013-02-14 07:30:40 +08:00
|
|
|
char **evp = ev;
|
2003-03-18 09:56:11 +08:00
|
|
|
while (*evp++ != NULL)
|
|
|
|
;
|
2013-02-14 07:30:40 +08:00
|
|
|
auxvec = (ElfW(auxv_t) *) evp;
|
2003-03-16 07:09:11 +08:00
|
|
|
}
|
|
|
|
# endif
|
|
|
|
_dl_aux_init (auxvec);
|
2002-07-24 07:12:01 +08:00
|
|
|
# endif
|
2013-03-29 07:15:48 +08:00
|
|
|
|
2017-01-01 02:02:17 +08:00
|
|
|
__tunables_init (__environ);
|
|
|
|
|
2017-05-31 09:08:32 +08:00
|
|
|
ARCH_INIT_CPU_FEATURES ();
|
|
|
|
|
2021-01-20 01:17:01 +08:00
|
|
|
/* Do static pie self relocation after tunables and cpu features
|
|
|
|
are setup for ifunc resolvers. Before this point relocations
|
|
|
|
must be avoided. */
|
|
|
|
_dl_relocate_static_pie ();
|
|
|
|
|
2012-08-22 06:01:27 +08:00
|
|
|
/* Perform IREL{,A} relocations. */
|
2017-07-18 04:48:59 +08:00
|
|
|
ARCH_SETUP_IREL ();
|
2009-11-25 03:17:06 +08:00
|
|
|
|
2016-12-26 17:08:34 +08:00
|
|
|
/* The stack guard goes into the TCB, so initialize it early. */
|
2018-03-17 08:28:41 +08:00
|
|
|
ARCH_SETUP_TLS ();
|
1999-07-10 00:18:17 +08:00
|
|
|
|
2017-07-18 04:48:59 +08:00
|
|
|
/* In some architectures, IREL{,A} relocations happen after TLS setup in
|
|
|
|
order to let IFUNC resolvers benefit from TCB information, e.g. powerpc's
|
|
|
|
hwcap and platform fields available in the TCB. */
|
|
|
|
ARCH_APPLY_IREL ();
|
|
|
|
|
2005-06-27 02:14:26 +08:00
|
|
|
/* Set up the stack checker's canary. */
|
2009-01-11 12:40:39 +08:00
|
|
|
uintptr_t stack_chk_guard = _dl_setup_stack_chk_guard (_dl_random);
|
2007-08-13 03:03:54 +08:00
|
|
|
# ifdef THREAD_SET_STACK_GUARD
|
2005-06-27 02:14:26 +08:00
|
|
|
THREAD_SET_STACK_GUARD (stack_chk_guard);
|
2007-08-13 03:03:54 +08:00
|
|
|
# else
|
2005-06-27 02:14:26 +08:00
|
|
|
__stack_chk_guard = stack_chk_guard;
|
2007-08-13 03:03:54 +08:00
|
|
|
# endif
|
2013-09-23 12:52:09 +08:00
|
|
|
|
2016-12-26 17:08:34 +08:00
|
|
|
/* Initialize libpthread if linked in. */
|
|
|
|
if (__pthread_initialize_minimal != NULL)
|
|
|
|
__pthread_initialize_minimal ();
|
|
|
|
|
2013-09-23 12:52:09 +08:00
|
|
|
/* Set up the pointer guard value. */
|
|
|
|
uintptr_t pointer_chk_guard = _dl_setup_pointer_guard (_dl_random,
|
|
|
|
stack_chk_guard);
|
|
|
|
# ifdef THREAD_SET_POINTER_GUARD
|
|
|
|
THREAD_SET_POINTER_GUARD (pointer_chk_guard);
|
|
|
|
# else
|
|
|
|
__pointer_chk_guard_local = pointer_chk_guard;
|
|
|
|
# endif
|
|
|
|
|
2017-07-18 04:48:59 +08:00
|
|
|
#endif /* !SHARED */
|
2007-08-13 03:03:54 +08:00
|
|
|
|
1998-03-08 23:26:29 +08:00
|
|
|
/* Register the destructor of the dynamic linker if there is any. */
|
2014-02-10 21:45:42 +08:00
|
|
|
if (__glibc_likely (rtld_fini != NULL))
|
2001-02-27 01:53:15 +08:00
|
|
|
__cxa_atexit ((void (*) (void *)) rtld_fini, NULL, NULL);
|
1998-03-08 23:26:29 +08:00
|
|
|
|
2005-02-15 05:25:50 +08:00
|
|
|
#ifndef SHARED
|
elf: Implement __libc_early_init
This function is defined in libc.so, and the dynamic loader calls
right after relocation has been finished, before any ELF constructors
or the preinit function is invoked. It is also used in the static
build for initializing parts of the static libc.
To locate __libc_early_init, a direct symbol lookup function is used,
_dl_lookup_direct. It does not search the entire symbol scope and
consults merely a single link map. This function could also be used
to implement lookups in the vDSO (as an optimization).
A per-namespace variable (libc_map) is added for locating libc.so,
to avoid repeated traversals of the search scope. It is similar to
GL(dl_initfirst). An alternative would have been to thread a context
argument from _dl_open down to _dl_map_object_from_fd (where libc.so
is identified). This could have avoided the global variable, but
the change would be larger as a result. It would not have been
possible to use this to replace GL(dl_initfirst) because that global
variable is used to pass the function pointer past the stack switch
from dl_main to the main program. Replacing that requires adding
a new argument to _dl_init, which in turn needs changes to the
architecture-specific libc.so startup code written in assembler.
__libc_early_init should not be used to replace _dl_var_init (as
it exists today on some architectures). Instead, _dl_lookup_direct
should be used to look up a new variable symbol in libc.so, and
that should then be initialized from the dynamic loader, immediately
after the object has been loaded in _dl_map_object_from_fd (before
relocation is run). This way, more IFUNC resolvers which depend on
these variables will work.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
2020-04-25 04:31:15 +08:00
|
|
|
/* Perform early initialization. In the shared case, this function
|
|
|
|
is called from the dynamic loader as early as possible. */
|
2020-04-29 21:44:03 +08:00
|
|
|
__libc_early_init (true);
|
elf: Implement __libc_early_init
This function is defined in libc.so, and the dynamic loader calls
right after relocation has been finished, before any ELF constructors
or the preinit function is invoked. It is also used in the static
build for initializing parts of the static libc.
To locate __libc_early_init, a direct symbol lookup function is used,
_dl_lookup_direct. It does not search the entire symbol scope and
consults merely a single link map. This function could also be used
to implement lookups in the vDSO (as an optimization).
A per-namespace variable (libc_map) is added for locating libc.so,
to avoid repeated traversals of the search scope. It is similar to
GL(dl_initfirst). An alternative would have been to thread a context
argument from _dl_open down to _dl_map_object_from_fd (where libc.so
is identified). This could have avoided the global variable, but
the change would be larger as a result. It would not have been
possible to use this to replace GL(dl_initfirst) because that global
variable is used to pass the function pointer past the stack switch
from dl_main to the main program. Replacing that requires adding
a new argument to _dl_init, which in turn needs changes to the
architecture-specific libc.so startup code written in assembler.
__libc_early_init should not be used to replace _dl_var_init (as
it exists today on some architectures). Instead, _dl_lookup_direct
should be used to look up a new variable symbol in libc.so, and
that should then be initialized from the dynamic loader, immediately
after the object has been loaded in _dl_map_object_from_fd (before
relocation is run). This way, more IFUNC resolvers which depend on
these variables will work.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
2020-04-25 04:31:15 +08:00
|
|
|
|
2000-03-31 00:30:49 +08:00
|
|
|
/* Call the initializer of the libc. This is only needed here if we
|
|
|
|
are compiling for the static library in which case we haven't
|
|
|
|
run the constructors in `_dl_start_user'. */
|
1998-03-18 22:42:25 +08:00
|
|
|
__libc_init_first (argc, argv, __environ);
|
|
|
|
|
2021-02-25 19:10:57 +08:00
|
|
|
/* Register the destructor of the statically-linked program. */
|
|
|
|
__cxa_atexit (call_fini, NULL, NULL);
|
2005-02-15 05:25:50 +08:00
|
|
|
|
2003-05-06 13:55:00 +08:00
|
|
|
/* Some security at this point. Prevent starting a SUID binary where
|
|
|
|
the standard file descriptors are not opened. We have to do this
|
|
|
|
only for statically linked applications since otherwise the dynamic
|
|
|
|
loader did the work already. */
|
|
|
|
if (__builtin_expect (__libc_enable_secure, 0))
|
|
|
|
__libc_check_standard_fds ();
|
2021-02-25 19:10:57 +08:00
|
|
|
#endif /* !SHARED */
|
2003-05-06 13:55:00 +08:00
|
|
|
|
1998-04-07 03:08:46 +08:00
|
|
|
/* Call the initializer of the program, if any. */
|
2000-03-31 13:50:02 +08:00
|
|
|
#ifdef SHARED
|
2004-03-05 18:29:47 +08:00
|
|
|
if (__builtin_expect (GLRO(dl_debug_mask) & DL_DEBUG_IMPCALLS, 0))
|
2004-03-06 16:19:29 +08:00
|
|
|
GLRO(dl_debug_printf) ("\ninitialize program: %s\n\n", argv[0]);
|
2021-02-25 19:10:57 +08:00
|
|
|
|
|
|
|
if (init != NULL)
|
|
|
|
/* This is a legacy program which supplied its own init
|
|
|
|
routine. */
|
2005-07-08 07:00:02 +08:00
|
|
|
(*init) (argc, argv, __environ MAIN_AUXVEC_PARAM);
|
2021-02-25 19:10:57 +08:00
|
|
|
else
|
|
|
|
/* This is a current program. Use the dynamic segment to find
|
|
|
|
constructors. */
|
|
|
|
call_init (argc, argv, __environ);
|
1998-03-08 23:26:29 +08:00
|
|
|
|
2005-01-07 06:40:27 +08:00
|
|
|
/* Auditing checkpoint: we have a new object. */
|
2021-07-23 04:10:57 +08:00
|
|
|
_dl_audit_preinit (GL(dl_ns)[LM_ID_BASE]._ns_loaded);
|
2005-01-07 06:40:27 +08:00
|
|
|
|
2014-02-10 21:45:42 +08:00
|
|
|
if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_IMPCALLS))
|
2004-03-06 16:19:29 +08:00
|
|
|
GLRO(dl_debug_printf) ("\ntransferring control: %s\n\n", argv[0]);
|
2021-07-23 04:10:57 +08:00
|
|
|
#else /* !SHARED */
|
|
|
|
call_init (argc, argv, __environ);
|
1998-03-18 22:42:25 +08:00
|
|
|
|
2014-04-12 00:43:58 +08:00
|
|
|
_dl_debug_initialize (0, LM_ID_BASE);
|
|
|
|
#endif
|
2002-09-15 10:37:32 +08:00
|
|
|
|
2021-04-22 01:49:50 +08:00
|
|
|
__libc_start_call_main (main, argc, argv MAIN_AUXVEC_PARAM);
|
1998-03-07 01:21:43 +08:00
|
|
|
}
|
2021-02-25 19:10:57 +08:00
|
|
|
|
|
|
|
/* Starting with glibc 2.34, the init parameter is always NULL. Older
|
|
|
|
libcs are not prepared to handle that. The macro
|
|
|
|
DEFINE_LIBC_START_MAIN_VERSION creates GLIBC_2.34 alias, so that
|
|
|
|
newly linked binaries reflect that dependency. The macros below
|
|
|
|
expect that the exported function is called
|
|
|
|
__libc_start_main_impl. */
|
|
|
|
#ifdef SHARED
|
|
|
|
# define DEFINE_LIBC_START_MAIN_VERSION \
|
|
|
|
DEFINE_LIBC_START_MAIN_VERSION_1 \
|
|
|
|
strong_alias (__libc_start_main_impl, __libc_start_main_alias_2) \
|
|
|
|
versioned_symbol (libc, __libc_start_main_alias_2, __libc_start_main, \
|
|
|
|
GLIBC_2_34);
|
|
|
|
|
|
|
|
# if SHLIB_COMPAT(libc, GLIBC_2_0, GLIBC_2_34)
|
|
|
|
# define DEFINE_LIBC_START_MAIN_VERSION_1 \
|
|
|
|
strong_alias (__libc_start_main_impl, __libc_start_main_alias_1) \
|
|
|
|
compat_symbol (libc, __libc_start_main_alias_1, __libc_start_main, GLIBC_2_0);
|
|
|
|
# else
|
|
|
|
# define DEFINE_LIBC_START_MAIN_VERSION_1
|
|
|
|
# endif
|
|
|
|
#else /* !SHARED */
|
|
|
|
/* Enable calling the function under its exported name. */
|
|
|
|
# define DEFINE_LIBC_START_MAIN_VERSION \
|
|
|
|
strong_alias (__libc_start_main_impl, __libc_start_main)
|
|
|
|
#endif
|
|
|
|
|
|
|
|
/* Only define the version information if LIBC_START_MAIN was not set.
|
|
|
|
If there is a wrapper file, it must expand
|
|
|
|
DEFINE_LIBC_START_MAIN_VERSION on its own. */
|
|
|
|
#if DO_DEFINE_LIBC_START_MAIN_VERSION
|
|
|
|
DEFINE_LIBC_START_MAIN_VERSION
|
|
|
|
#endif
|