[PATCH v3 10/37] csu: Move calling main out of __libc_start_main_impl
Florian Weimer
fweimer@redhat.com
Tue Mar 16 17:29:07 GMT 2021
This code depends on whether glibc has unwinding support for
a particular port.
---
csu/libc-start.c | 74 ++--------------------
sysdeps/generic/libc_start_call_main.h | 24 +++++++
sysdeps/nptl/libc_start_call_main.h | 88 ++++++++++++++++++++++++++
3 files changed, 116 insertions(+), 70 deletions(-)
create mode 100644 sysdeps/generic/libc_start_call_main.h
create mode 100644 sysdeps/nptl/libc_start_call_main.h
diff --git a/csu/libc-start.c b/csu/libc-start.c
index 05ff7afddf..8688cba76d 100644
--- a/csu/libc-start.c
+++ b/csu/libc-start.c
@@ -58,12 +58,6 @@ uintptr_t __pointer_chk_guard_local
# endif
#endif
-#ifdef HAVE_PTR_NTHREADS
-/* We need atomic operations. */
-# include <atomic.h>
-#endif
-
-
#ifndef SHARED
# include <link.h>
# include <dl-irel.h>
@@ -123,6 +117,9 @@ apply_irel (void)
# define ARCH_INIT_CPU_FEATURES()
#endif
+/* Obtain the definition of __libc_start_call_main. */
+#include <libc_start_call_main.h>
+
#ifdef SHARED
/* Initialization for dynamic executables. Find the main executable
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 (*rtld_fini) (void), void *stack_end)
{
- /* Result of the 'main' function. */
- int result;
-
#ifndef SHARED
char **ev = &argv[argc + 1];
@@ -413,68 +407,8 @@ LIBC_START_MAIN (int (*main) (int, char **, char ** MAIN_AUXVEC_DECL),
#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;
- 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);
+ __libc_start_call_main (main, argc, argv MAIN_AUXVEC_PARAM);
}
/* Starting with glibc 2.34, the init parameter is always NULL. Older
diff --git a/sysdeps/generic/libc_start_call_main.h b/sysdeps/generic/libc_start_call_main.h
new file mode 100644
index 0000000000..8a06eec4a3
--- /dev/null
+++ b/sysdeps/generic/libc_start_call_main.h
@@ -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));
+}
diff --git a/sysdeps/nptl/libc_start_call_main.h b/sysdeps/nptl/libc_start_call_main.h
new file mode 100644
index 0000000000..5218e7ab1e
--- /dev/null
+++ b/sysdeps/nptl/libc_start_call_main.h
@@ -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);
+}
--
2.29.2
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