/* Copyright (C) 1998-2018 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
<http://www.gnu.org/licenses/>. */
#include <assert.h>
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <ldsodefs.h>
#include <exit-thread.h>
#include <libc-internal.h>
#include <elf/dl-tunables.h>
extern void __libc_init_first (int argc, char **argv, char **envp);
#include <tls.h>
#ifndef SHARED
# include <dl-osinfo.h>
# 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
# ifndef THREAD_SET_POINTER_GUARD
/* Only exported for architectures that don't store the pointer guard
value in thread local area. */
uintptr_t __pointer_chk_guard_local
attribute_relro attribute_hidden __attribute__ ((nocommon));
# endif
#endif
#ifdef HAVE_PTR_NTHREADS
/* We need atomic operations. */
# include <atomic.h>
#endif
#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)
{
# 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));
for (const IREL_T *ipltent = IPLT_START; ipltent < IPLT_END; ++ipltent)
IREL (ipltent);
# endif
}
#endif
#ifdef LIBC_START_MAIN
# ifdef LIBC_START_DISABLE_INLINE
# define STATIC static
# else
# define STATIC static inline __attribute__ ((always_inline))
# endif
#else
# define STATIC
# define LIBC_START_MAIN __libc_start_main
#endif
#ifdef MAIN_AUXVEC_ARG
/* 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
#endif
#ifndef ARCH_INIT_CPU_FEATURES
# define ARCH_INIT_CPU_FEATURES()
#endif
#include <libc-start.h>
STATIC int LIBC_START_MAIN (int (*main) (int, char **, char **
MAIN_AUXVEC_DECL),
int argc,
char **argv,
#ifdef LIBC_START_MAIN_AUXVEC_ARG
ElfW(auxv_t) *auxvec,
#endif
__typeof (main) init,
void (*fini) (void),
void (*rtld_fini) (void),
void *stack_end)
__attribute__ ((noreturn));
/* Note: the fini parameter is ignored here for shared library. It
is registered with __cxa_atexit. This had the disadvantage that
finalizers were called in more than one place. */
STATIC int
LIBC_START_MAIN (int (*main) (int, char **, char ** MAIN_AUXVEC_DECL),
int argc, char **argv,
#ifdef LIBC_START_MAIN_AUXVEC_ARG
ElfW(auxv_t) *auxvec,
#endif
__typeof (main) init,
void (*fini) (void),
void (*rtld_fini) (void), void *stack_end)
{
/* Result of the 'main' function. */
int result;
__libc_multiple_libcs = &_dl_starting_up && !_dl_starting_up;
#ifndef SHARED
_dl_relocate_static_pie ();
char **ev = &argv[argc + 1];
__environ = ev;
/* Store the lowest stack address. This is done in ld.so if this is
the code for the DSO. */
__libc_stack_end = stack_end;
# 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. */
# ifndef LIBC_START_MAIN_AUXVEC_ARG
ElfW(auxv_t) *auxvec;
{
char **evp = ev;
while (*evp++ != NULL)
;
auxvec = (ElfW(auxv_t) *) evp;
}
# endif
_dl_aux_init (auxvec);
if (GL(dl_phdr) == NULL)
# endif
{
/* Starting from binutils-2.23, the linker will define the
magic symbol __ehdr_start to point to our own ELF header
if it is visible in a segment that also includes the phdrs.
So we can set up _dl_phdr and _dl_phnum even without any
information from auxv. */
extern const ElfW(Ehdr) __ehdr_start
__attribute__ ((weak, visibility ("hidden")));
if (&__ehdr_start != NULL)
{
assert (__ehdr_start.e_phentsize == sizeof *GL(dl_phdr));
GL(dl_phdr) = (const void *) &__ehdr_start + __ehdr_start.e_phoff;
GL(dl_phnum) = __ehdr_start.e_phnum;
}
}
/* Initialize very early so that tunables can use it. */
__libc_init_secure ();
__tunables_init (__environ);
ARCH_INIT_CPU_FEATURES ();
/* Perform IREL{,A} relocations. */
ARCH_SETUP_IREL ();
/* The stack guard goes into the TCB, so initialize it early. */
ARCH_SETUP_TLS ();
/* 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 ();
/* Set up the stack checker's canary. */
uintptr_t stack_chk_guard = _dl_setup_stack_chk_guard (_dl_random);
# ifdef THREAD_SET_STACK_GUARD
THREAD_SET_STACK_GUARD (stack_chk_guard);
# else
__stack_chk_guard = stack_chk_guard;
# endif
# ifdef DL_SYSDEP_OSCHECK
if (!__libc_multiple_libcs)
{
/* This needs to run to initiliaze _dl_osversion before TLS
setup might check it. */
DL_SYSDEP_OSCHECK (__libc_fatal);
}
# endif
/* Initialize libpthread if linked in. */
if (__pthread_initialize_minimal != NULL)
__pthread_initialize_minimal ();
/* 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
#endif /* !SHARED */
/* Register the destructor of the dynamic linker if there is any. */
if (__glibc_likely (rtld_fini != NULL))
__cxa_atexit ((void (*) (void *)) rtld_fini, NULL, NULL);
#ifndef SHARED
/* 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'. */
__libc_init_first (argc, argv, __environ);
/* Register the destructor of the program, if any. */
if (fini)
__cxa_atexit ((void (*) (void *)) fini, NULL, NULL);
/* 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 ();
#endif
/* Call the initializer of the program, if any. */
#ifdef SHARED
if (__builtin_expect (GLRO(dl_debug_mask) & DL_DEBUG_IMPCALLS, 0))
GLRO(dl_debug_printf) ("\ninitialize program: %s\n\n", argv[0]);
#endif
if (init)
(*init) (argc, argv, __environ MAIN_AUXVEC_PARAM);
#ifdef SHARED
/* Auditing checkpoint: we have a new object. */
if (__glibc_unlikely (GLRO(dl_naudit) > 0))
{
struct audit_ifaces *afct = GLRO(dl_audit);
struct link_map *head = GL(dl_ns)[LM_ID_BASE]._ns_loaded;
for (unsigned int cnt = 0; cnt < GLRO(dl_naudit); ++cnt)
{
if (afct->preinit != NULL)
afct->preinit (&head->l_audit[cnt].cookie);
afct = afct->next;
}
}
#endif
#ifdef SHARED
if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_IMPCALLS))
GLRO(dl_debug_printf) ("\ntransferring control: %s\n\n", argv[0]);
#endif
#ifndef SHARED
_dl_debug_initialize (0, LM_ID_BASE);
#endif
#ifdef HAVE_CLEANUP_JMP_BUF
/* Memory for the cancellation buffer. */
struct pthread_unwind_buf unwind_buf;
int not_first_call;
not_first_call = setjmp ((struct __jmp_buf_tag *) unwind_buf.cancel_jmp_buf);
if (__glibc_likely (! not_first_call))
{
struct pthread *self = THREAD_SELF;
/* Store old info. */
unwind_buf.priv.data.prev = THREAD_GETMEM (self, cleanup_jmp_buf);
unwind_buf.priv.data.cleanup = THREAD_GETMEM (self, cleanup);
/* Store the new cleanup handler info. */
THREAD_SETMEM (self, cleanup_jmp_buf, &unwind_buf);
/* Run the program. */
result = main (argc, argv, __environ MAIN_AUXVEC_PARAM);
}
else
{
/* Remove the thread-local data. */
# ifdef SHARED
PTHFCT_CALL (ptr__nptl_deallocate_tsd, ());
# else
extern void __nptl_deallocate_tsd (void) __attribute ((weak));
__nptl_deallocate_tsd ();
# endif
/* One less thread. Decrement the counter. If it is zero we
terminate the entire process. */
result = 0;
# ifdef SHARED
unsigned int *ptr = __libc_pthread_functions.ptr_nthreads;
# ifdef PTR_DEMANGLE
PTR_DEMANGLE (ptr);
# endif
# else
extern unsigned int __nptl_nthreads __attribute ((weak));
unsigned int *const ptr = &__nptl_nthreads;
# endif
if (! atomic_decrement_and_test (ptr))
/* Not much left to do but to exit the thread, not the process. */
__exit_thread ();
}
#else
/* Nothing fancy, just call the function. */
result = main (argc, argv, __environ MAIN_AUXVEC_PARAM);
#endif
exit (result);
}