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/>. */
24 extern void __libc_init_first (int argc, char **argv, char **envp);
26 extern void __libc_csu_irel (void);
29 extern int __libc_multiple_libcs;
33 # include <dl-osinfo.h>
34 extern void __pthread_initialize_minimal (void);
35 # ifndef THREAD_SET_STACK_GUARD
36 /* Only exported for architectures that don't store the stack guard canary
37 in thread local area. */
38 uintptr_t __stack_chk_guard attribute_relro;
42 #ifdef HAVE_PTR_NTHREADS
43 /* We need atomic operations. */
52 # ifdef ELF_MACHINE_IRELA
53 # define IREL_T ElfW(Rela)
54 # define IPLT_START __rela_iplt_start
55 # define IPLT_END __rela_iplt_end
56 # define IREL elf_irela
57 # elif defined ELF_MACHINE_IREL
58 # define IREL_T ElfW(Rel)
59 # define IPLT_START __rel_iplt_start
60 # define IPLT_END __rel_iplt_end
61 # define IREL elf_irel
68 /* We use weak references for these so that we'll still work with a linker
69 that doesn't define them. Such a linker doesn't support IFUNC at all
70 and so uses won't work, but a statically-linked program that doesn't
71 use any IFUNC symbols won't have a problem. */
72 extern const IREL_T IPLT_START[] __attribute__ ((weak));
73 extern const IREL_T IPLT_END[] __attribute__ ((weak));
74 for (const IREL_T *ipltent = IPLT_START; ipltent < IPLT_END; ++ipltent)
81 #ifdef LIBC_START_MAIN
82 # ifdef LIBC_START_DISABLE_INLINE
83 # define STATIC static
85 # define STATIC static inline __attribute__ ((always_inline))
89 # define LIBC_START_MAIN BP_SYM (__libc_start_main)
92 #ifdef MAIN_AUXVEC_ARG
93 /* main gets passed a pointer to the auxiliary. */
94 # define MAIN_AUXVEC_DECL , void *
95 # define MAIN_AUXVEC_PARAM , auxvec
97 # define MAIN_AUXVEC_DECL
98 # define MAIN_AUXVEC_PARAM
101 STATIC int LIBC_START_MAIN (int (*main) (int, char **, char **
105 #ifdef LIBC_START_MAIN_AUXVEC_ARG
106 ElfW(auxv_t) *auxvec,
108 __typeof (main) init,
110 void (*rtld_fini) (void),
112 __attribute__ ((noreturn));
115 /* Note: the fini parameter is ignored here for shared library. It
116 is registered with __cxa_atexit. This had the disadvantage that
117 finalizers were called in more than one place. */
119 LIBC_START_MAIN (int (*main) (int, char **, char ** MAIN_AUXVEC_DECL),
120 int argc, char **argv,
121 #ifdef LIBC_START_MAIN_AUXVEC_ARG
122 ElfW(auxv_t) *auxvec,
124 __typeof (main) init,
126 void (*rtld_fini) (void), void *stack_end)
128 /* Result of the 'main' function. */
131 __libc_multiple_libcs = &_dl_starting_up && !_dl_starting_up;
134 char **ev = &argv[argc + 1];
138 /* Store the lowest stack address. This is done in ld.so if this is
139 the code for the DSO. */
140 __libc_stack_end = stack_end;
142 # ifdef HAVE_AUX_VECTOR
143 /* First process the auxiliary vector since we need to find the
144 program header to locate an eventually present PT_TLS entry. */
145 # ifndef LIBC_START_MAIN_AUXVEC_ARG
146 ElfW(auxv_t) *auxvec;
149 while (*evp++ != NULL)
151 auxvec = (ElfW(auxv_t) *) evp;
154 _dl_aux_init (auxvec);
156 # ifdef DL_SYSDEP_OSCHECK
157 if (!__libc_multiple_libcs)
159 /* This needs to run to initiliaze _dl_osversion before TLS
160 setup might check it. */
161 DL_SYSDEP_OSCHECK (__libc_fatal);
165 /* Perform IREL{,A} relocations. */
168 /* Initialize the thread library at least a bit since the libgcc
169 functions are using thread functions if these are available and
170 we need to setup errno. */
171 __pthread_initialize_minimal ();
173 /* Set up the stack checker's canary. */
174 uintptr_t stack_chk_guard = _dl_setup_stack_chk_guard (_dl_random);
175 # ifdef THREAD_SET_STACK_GUARD
176 THREAD_SET_STACK_GUARD (stack_chk_guard);
178 __stack_chk_guard = stack_chk_guard;
182 /* Register the destructor of the dynamic linker if there is any. */
183 if (__builtin_expect (rtld_fini != NULL, 1))
184 __cxa_atexit ((void (*) (void *)) rtld_fini, NULL, NULL);
187 /* Call the initializer of the libc. This is only needed here if we
188 are compiling for the static library in which case we haven't
189 run the constructors in `_dl_start_user'. */
190 __libc_init_first (argc, argv, __environ);
192 /* Register the destructor of the program, if any. */
194 __cxa_atexit ((void (*) (void *)) fini, NULL, NULL);
196 /* Some security at this point. Prevent starting a SUID binary where
197 the standard file descriptors are not opened. We have to do this
198 only for statically linked applications since otherwise the dynamic
199 loader did the work already. */
200 if (__builtin_expect (__libc_enable_secure, 0))
201 __libc_check_standard_fds ();
204 /* Call the initializer of the program, if any. */
206 if (__builtin_expect (GLRO(dl_debug_mask) & DL_DEBUG_IMPCALLS, 0))
207 GLRO(dl_debug_printf) ("\ninitialize program: %s\n\n", argv[0]);
210 (*init) (argc, argv, __environ MAIN_AUXVEC_PARAM);
213 /* Auditing checkpoint: we have a new object. */
214 if (__builtin_expect (GLRO(dl_naudit) > 0, 0))
216 struct audit_ifaces *afct = GLRO(dl_audit);
217 struct link_map *head = GL(dl_ns)[LM_ID_BASE]._ns_loaded;
218 for (unsigned int cnt = 0; cnt < GLRO(dl_naudit); ++cnt)
220 if (afct->preinit != NULL)
221 afct->preinit (&head->l_audit[cnt].cookie);
229 if (__builtin_expect (GLRO(dl_debug_mask) & DL_DEBUG_IMPCALLS, 0))
230 GLRO(dl_debug_printf) ("\ntransferring control: %s\n\n", argv[0]);
233 #ifdef HAVE_CLEANUP_JMP_BUF
234 /* Memory for the cancellation buffer. */
235 struct pthread_unwind_buf unwind_buf;
238 not_first_call = setjmp ((struct __jmp_buf_tag *) unwind_buf.cancel_jmp_buf);
239 if (__builtin_expect (! not_first_call, 1))
241 struct pthread *self = THREAD_SELF;
243 /* Store old info. */
244 unwind_buf.priv.data.prev = THREAD_GETMEM (self, cleanup_jmp_buf);
245 unwind_buf.priv.data.cleanup = THREAD_GETMEM (self, cleanup);
247 /* Store the new cleanup handler info. */
248 THREAD_SETMEM (self, cleanup_jmp_buf, &unwind_buf);
250 /* Run the program. */
251 result = main (argc, argv, __environ MAIN_AUXVEC_PARAM);
255 /* Remove the thread-local data. */
257 PTHFCT_CALL (ptr__nptl_deallocate_tsd, ());
259 extern void __nptl_deallocate_tsd (void) __attribute ((weak));
260 __nptl_deallocate_tsd ();
263 /* One less thread. Decrement the counter. If it is zero we
264 terminate the entire process. */
267 unsigned int *ptr = __libc_pthread_functions.ptr_nthreads;
272 extern unsigned int __nptl_nthreads __attribute ((weak));
273 unsigned int *const ptr = &__nptl_nthreads;
276 if (! atomic_decrement_and_test (ptr))
277 /* Not much left to do but to exit the thread, not the process. */
281 /* Nothing fancy, just call the function. */
282 result = main (argc, argv, __environ MAIN_AUXVEC_PARAM);