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csu: Move calling main out of __libc_start_main_impl

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This code depends on whether glibc has unwinding support for
a particular port.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
This commit is contained in:
Florian Weimer
2021-04-21 19:49:50 +02:00
parent 1d95b035c7
commit 130fca173f
3 changed files with 116 additions and 70 deletions
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74
csu/libc-start.c
View File

@ -58,12 +58,6 @@ uintptr_t __pointer_chk_guard_local
# endif # endif
#endif #endif
#ifdef HAVE_PTR_NTHREADS
/* We need atomic operations. */
# include <atomic.h>
#endif
#ifndef SHARED #ifndef SHARED
# include <link.h> # include <link.h>
# include <dl-irel.h> # include <dl-irel.h>
@ -123,6 +117,9 @@ apply_irel (void)
# define ARCH_INIT_CPU_FEATURES() # define ARCH_INIT_CPU_FEATURES()
#endif #endif
/* Obtain the definition of __libc_start_call_main. */
#include <libc_start_call_main.h>
#ifdef SHARED #ifdef SHARED
/* Initialization for dynamic executables. Find the main executable /* Initialization for dynamic executables. Find the main executable
link map and run its init functions. */ link map and run its init functions. */
@ -245,9 +242,6 @@ LIBC_START_MAIN (int (*main) (int, char **, char ** MAIN_AUXVEC_DECL),
void (*fini) (void), void (*fini) (void),
void (*rtld_fini) (void), void *stack_end) void (*rtld_fini) (void), void *stack_end)
{ {
/* Result of the 'main' function. */
int result;
#ifndef SHARED #ifndef SHARED
char **ev = &argv[argc + 1]; char **ev = &argv[argc + 1];
@ -413,68 +407,8 @@ LIBC_START_MAIN (int (*main) (int, char **, char ** MAIN_AUXVEC_DECL),
#ifndef SHARED #ifndef SHARED
_dl_debug_initialize (0, LM_ID_BASE); _dl_debug_initialize (0, LM_ID_BASE);
#endif #endif
#ifdef HAVE_CLEANUP_JMP_BUF
/* Memory for the cancellation buffer. */
struct pthread_unwind_buf unwind_buf;
int not_first_call; __libc_start_call_main (main, argc, argv MAIN_AUXVEC_PARAM);
DIAG_PUSH_NEEDS_COMMENT;
#if __GNUC_PREREQ (7, 0)
/* This call results in a -Wstringop-overflow warning because struct
pthread_unwind_buf is smaller than jmp_buf. setjmp and longjmp
do not use anything beyond the common prefix (they never access
the saved signal mask), so that is a false positive. */
DIAG_IGNORE_NEEDS_COMMENT (11, "-Wstringop-overflow=");
#endif
not_first_call = setjmp ((struct __jmp_buf_tag *) unwind_buf.cancel_jmp_buf);
DIAG_POP_NEEDS_COMMENT;
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);
} }
/* Starting with glibc 2.34, the init parameter is always NULL. Older /* Starting with glibc 2.34, the init parameter is always NULL. Older

24
sysdeps/generic/libc_start_call_main.h Normal file
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@ -0,0 +1,24 @@
/* Invoking main from __libc_start. Generic version without unwinding.
Copyright (C) 1998-2021 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/>. */
_Noreturn static __always_inline void
__libc_start_call_main (int (*main) (int, char **, char ** MAIN_AUXVEC_DECL),
int argc, char **argv MAIN_AUXVEC_DECL)
{
exit (main (argc, argv, __environ MAIN_AUXVEC_PARAM));
}

88
sysdeps/nptl/libc_start_call_main.h Normal file
View File

@ -0,0 +1,88 @@
/* Invoking main from __libc_start_main. nptl version.
Copyright (C) 1998-2021 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 <atomic.h>
_Noreturn static void
__libc_start_call_main (int (*main) (int, char **, char ** MAIN_AUXVEC_DECL),
int argc, char **argv
#ifdef LIBC_START_MAIN_AUXVEC_ARG
, ElfW(auxv_t) *auxvec
#endif
)
{
int result;
/* Memory for the cancellation buffer. */
struct pthread_unwind_buf unwind_buf;
int not_first_call;
DIAG_PUSH_NEEDS_COMMENT;
#if __GNUC_PREREQ (7, 0)
/* This call results in a -Wstringop-overflow warning because struct
pthread_unwind_buf is smaller than jmp_buf. setjmp and longjmp
do not use anything beyond the common prefix (they never access
the saved signal mask), so that is a false positive. */
DIAG_IGNORE_NEEDS_COMMENT (11, "-Wstringop-overflow=");
#endif
not_first_call = setjmp ((struct __jmp_buf_tag *) unwind_buf.cancel_jmp_buf);
DIAG_POP_NEEDS_COMMENT;
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 ();
}
exit (result);
}