1 /* Copyright (C) 1998-2013 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the License, or (at your option) any later version.
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Lesser General Public License for more details.
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; if not, see
16 <http://www.gnu.org/licenses/>. */
23 extern void __libc_init_first (int argc, char **argv, char **envp);
25 extern void __libc_csu_irel (void);
28 extern int __libc_multiple_libcs;
32 # include <dl-osinfo.h>
33 extern void __pthread_initialize_minimal (void);
34 # ifndef THREAD_SET_STACK_GUARD
35 /* Only exported for architectures that don't store the stack guard canary
36 in thread local area. */
37 uintptr_t __stack_chk_guard attribute_relro;
41 #ifdef HAVE_PTR_NTHREADS
42 /* We need atomic operations. */
51 # ifdef ELF_MACHINE_IRELA
52 # define IREL_T ElfW(Rela)
53 # define IPLT_START __rela_iplt_start
54 # define IPLT_END __rela_iplt_end
55 # define IREL elf_irela
56 # elif defined ELF_MACHINE_IREL
57 # define IREL_T ElfW(Rel)
58 # define IPLT_START __rel_iplt_start
59 # define IPLT_END __rel_iplt_end
60 # define IREL elf_irel
67 /* We use weak references for these so that we'll still work with a linker
68 that doesn't define them. Such a linker doesn't support IFUNC at all
69 and so uses won't work, but a statically-linked program that doesn't
70 use any IFUNC symbols won't have a problem. */
71 extern const IREL_T IPLT_START[] __attribute__ ((weak));
72 extern const IREL_T IPLT_END[] __attribute__ ((weak));
73 for (const IREL_T *ipltent = IPLT_START; ipltent < IPLT_END; ++ipltent)
80 #ifdef LIBC_START_MAIN
81 # ifdef LIBC_START_DISABLE_INLINE
82 # define STATIC static
84 # define STATIC static inline __attribute__ ((always_inline))
88 # define LIBC_START_MAIN __libc_start_main
91 #ifdef MAIN_AUXVEC_ARG
92 /* main gets passed a pointer to the auxiliary. */
93 # define MAIN_AUXVEC_DECL , void *
94 # define MAIN_AUXVEC_PARAM , auxvec
96 # define MAIN_AUXVEC_DECL
97 # define MAIN_AUXVEC_PARAM
100 STATIC int LIBC_START_MAIN (int (*main) (int, char **, char **
104 #ifdef LIBC_START_MAIN_AUXVEC_ARG
105 ElfW(auxv_t) *auxvec,
107 __typeof (main) init,
109 void (*rtld_fini) (void),
111 __attribute__ ((noreturn));
114 /* Note: the fini parameter is ignored here for shared library. It
115 is registered with __cxa_atexit. This had the disadvantage that
116 finalizers were called in more than one place. */
118 LIBC_START_MAIN (int (*main) (int, char **, char ** MAIN_AUXVEC_DECL),
119 int argc, char **argv,
120 #ifdef LIBC_START_MAIN_AUXVEC_ARG
121 ElfW(auxv_t) *auxvec,
123 __typeof (main) init,
125 void (*rtld_fini) (void), void *stack_end)
127 /* Result of the 'main' function. */
130 __libc_multiple_libcs = &_dl_starting_up && !_dl_starting_up;
133 char **ev = &argv[argc + 1];
137 /* Store the lowest stack address. This is done in ld.so if this is
138 the code for the DSO. */
139 __libc_stack_end = stack_end;
141 # ifdef HAVE_AUX_VECTOR
142 /* First process the auxiliary vector since we need to find the
143 program header to locate an eventually present PT_TLS entry. */
144 # ifndef LIBC_START_MAIN_AUXVEC_ARG
145 ElfW(auxv_t) *auxvec;
148 while (*evp++ != NULL)
150 auxvec = (ElfW(auxv_t) *) evp;
153 _dl_aux_init (auxvec);
155 # ifdef DL_SYSDEP_OSCHECK
156 if (!__libc_multiple_libcs)
158 /* This needs to run to initiliaze _dl_osversion before TLS
159 setup might check it. */
160 DL_SYSDEP_OSCHECK (__libc_fatal);
164 /* Perform IREL{,A} relocations. */
167 /* Initialize the thread library at least a bit since the libgcc
168 functions are using thread functions if these are available and
169 we need to setup errno. */
170 __pthread_initialize_minimal ();
172 /* Set up the stack checker's canary. */
173 uintptr_t stack_chk_guard = _dl_setup_stack_chk_guard (_dl_random);
174 # ifdef THREAD_SET_STACK_GUARD
175 THREAD_SET_STACK_GUARD (stack_chk_guard);
177 __stack_chk_guard = stack_chk_guard;
181 /* Register the destructor of the dynamic linker if there is any. */
182 if (__builtin_expect (rtld_fini != NULL, 1))
183 __cxa_atexit ((void (*) (void *)) rtld_fini, NULL, NULL);
186 /* Call the initializer of the libc. This is only needed here if we
187 are compiling for the static library in which case we haven't
188 run the constructors in `_dl_start_user'. */
189 __libc_init_first (argc, argv, __environ);
191 /* Register the destructor of the program, if any. */
193 __cxa_atexit ((void (*) (void *)) fini, NULL, NULL);
195 /* Some security at this point. Prevent starting a SUID binary where
196 the standard file descriptors are not opened. We have to do this
197 only for statically linked applications since otherwise the dynamic
198 loader did the work already. */
199 if (__builtin_expect (__libc_enable_secure, 0))
200 __libc_check_standard_fds ();
203 /* Call the initializer of the program, if any. */
205 if (__builtin_expect (GLRO(dl_debug_mask) & DL_DEBUG_IMPCALLS, 0))
206 GLRO(dl_debug_printf) ("\ninitialize program: %s\n\n", argv[0]);
209 (*init) (argc, argv, __environ MAIN_AUXVEC_PARAM);
212 /* Auditing checkpoint: we have a new object. */
213 if (__builtin_expect (GLRO(dl_naudit) > 0, 0))
215 struct audit_ifaces *afct = GLRO(dl_audit);
216 struct link_map *head = GL(dl_ns)[LM_ID_BASE]._ns_loaded;
217 for (unsigned int cnt = 0; cnt < GLRO(dl_naudit); ++cnt)
219 if (afct->preinit != NULL)
220 afct->preinit (&head->l_audit[cnt].cookie);
228 if (__builtin_expect (GLRO(dl_debug_mask) & DL_DEBUG_IMPCALLS, 0))
229 GLRO(dl_debug_printf) ("\ntransferring control: %s\n\n", argv[0]);
232 #ifdef HAVE_CLEANUP_JMP_BUF
233 /* Memory for the cancellation buffer. */
234 struct pthread_unwind_buf unwind_buf;
237 not_first_call = setjmp ((struct __jmp_buf_tag *) unwind_buf.cancel_jmp_buf);
238 if (__builtin_expect (! not_first_call, 1))
240 struct pthread *self = THREAD_SELF;
242 /* Store old info. */
243 unwind_buf.priv.data.prev = THREAD_GETMEM (self, cleanup_jmp_buf);
244 unwind_buf.priv.data.cleanup = THREAD_GETMEM (self, cleanup);
246 /* Store the new cleanup handler info. */
247 THREAD_SETMEM (self, cleanup_jmp_buf, &unwind_buf);
249 /* Run the program. */
250 result = main (argc, argv, __environ MAIN_AUXVEC_PARAM);
254 /* Remove the thread-local data. */
256 PTHFCT_CALL (ptr__nptl_deallocate_tsd, ());
258 extern void __nptl_deallocate_tsd (void) __attribute ((weak));
259 __nptl_deallocate_tsd ();
262 /* One less thread. Decrement the counter. If it is zero we
263 terminate the entire process. */
266 unsigned int *ptr = __libc_pthread_functions.ptr_nthreads;
271 extern unsigned int __nptl_nthreads __attribute ((weak));
272 unsigned int *const ptr = &__nptl_nthreads;
275 if (! atomic_decrement_and_test (ptr))
276 /* Not much left to do but to exit the thread, not the process. */
280 /* Nothing fancy, just call the function. */
281 result = main (argc, argv, __environ MAIN_AUXVEC_PARAM);