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 __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
);
155 if (GL(dl_phdr
) == NULL
)
158 /* Starting from binutils-2.23, the linker will define the
159 magic symbol __ehdr_start to point to our own ELF header
160 if it is visible in a segment that also includes the phdrs.
161 So we can set up _dl_phdr and _dl_phnum even without any
162 information from auxv. */
164 extern const ElfW(Ehdr
) __ehdr_start
165 __attribute__ ((weak
, visibility ("hidden")));
166 if (&__ehdr_start
!= NULL
)
168 assert (__ehdr_start
.e_phentsize
== sizeof *GL(dl_phdr
));
169 GL(dl_phdr
) = (const void *) &__ehdr_start
+ __ehdr_start
.e_phoff
;
170 GL(dl_phnum
) = __ehdr_start
.e_phnum
;
174 # ifdef DL_SYSDEP_OSCHECK
175 if (!__libc_multiple_libcs
)
177 /* This needs to run to initiliaze _dl_osversion before TLS
178 setup might check it. */
179 DL_SYSDEP_OSCHECK (__libc_fatal
);
183 /* Perform IREL{,A} relocations. */
186 /* Initialize the thread library at least a bit since the libgcc
187 functions are using thread functions if these are available and
188 we need to setup errno. */
189 __pthread_initialize_minimal ();
191 /* Set up the stack checker's canary. */
192 uintptr_t stack_chk_guard
= _dl_setup_stack_chk_guard (_dl_random
);
193 # ifdef THREAD_SET_STACK_GUARD
194 THREAD_SET_STACK_GUARD (stack_chk_guard
);
196 __stack_chk_guard
= stack_chk_guard
;
200 /* Register the destructor of the dynamic linker if there is any. */
201 if (__builtin_expect (rtld_fini
!= NULL
, 1))
202 __cxa_atexit ((void (*) (void *)) rtld_fini
, NULL
, NULL
);
205 /* Call the initializer of the libc. This is only needed here if we
206 are compiling for the static library in which case we haven't
207 run the constructors in `_dl_start_user'. */
208 __libc_init_first (argc
, argv
, __environ
);
210 /* Register the destructor of the program, if any. */
212 __cxa_atexit ((void (*) (void *)) fini
, NULL
, NULL
);
214 /* Some security at this point. Prevent starting a SUID binary where
215 the standard file descriptors are not opened. We have to do this
216 only for statically linked applications since otherwise the dynamic
217 loader did the work already. */
218 if (__builtin_expect (__libc_enable_secure
, 0))
219 __libc_check_standard_fds ();
222 /* Call the initializer of the program, if any. */
224 if (__builtin_expect (GLRO(dl_debug_mask
) & DL_DEBUG_IMPCALLS
, 0))
225 GLRO(dl_debug_printf
) ("\ninitialize program: %s\n\n", argv
[0]);
228 (*init
) (argc
, argv
, __environ MAIN_AUXVEC_PARAM
);
231 /* Auditing checkpoint: we have a new object. */
232 if (__builtin_expect (GLRO(dl_naudit
) > 0, 0))
234 struct audit_ifaces
*afct
= GLRO(dl_audit
);
235 struct link_map
*head
= GL(dl_ns
)[LM_ID_BASE
]._ns_loaded
;
236 for (unsigned int cnt
= 0; cnt
< GLRO(dl_naudit
); ++cnt
)
238 if (afct
->preinit
!= NULL
)
239 afct
->preinit (&head
->l_audit
[cnt
].cookie
);
247 if (__builtin_expect (GLRO(dl_debug_mask
) & DL_DEBUG_IMPCALLS
, 0))
248 GLRO(dl_debug_printf
) ("\ntransferring control: %s\n\n", argv
[0]);
251 #ifdef HAVE_CLEANUP_JMP_BUF
252 /* Memory for the cancellation buffer. */
253 struct pthread_unwind_buf unwind_buf
;
256 not_first_call
= setjmp ((struct __jmp_buf_tag
*) unwind_buf
.cancel_jmp_buf
);
257 if (__builtin_expect (! not_first_call
, 1))
259 struct pthread
*self
= THREAD_SELF
;
261 /* Store old info. */
262 unwind_buf
.priv
.data
.prev
= THREAD_GETMEM (self
, cleanup_jmp_buf
);
263 unwind_buf
.priv
.data
.cleanup
= THREAD_GETMEM (self
, cleanup
);
265 /* Store the new cleanup handler info. */
266 THREAD_SETMEM (self
, cleanup_jmp_buf
, &unwind_buf
);
268 /* Run the program. */
269 result
= main (argc
, argv
, __environ MAIN_AUXVEC_PARAM
);
273 /* Remove the thread-local data. */
275 PTHFCT_CALL (ptr__nptl_deallocate_tsd
, ());
277 extern void __nptl_deallocate_tsd (void) __attribute ((weak
));
278 __nptl_deallocate_tsd ();
281 /* One less thread. Decrement the counter. If it is zero we
282 terminate the entire process. */
285 unsigned int *ptr
= __libc_pthread_functions
.ptr_nthreads
;
290 extern unsigned int __nptl_nthreads
__attribute ((weak
));
291 unsigned int *const ptr
= &__nptl_nthreads
;
294 if (! atomic_decrement_and_test (ptr
))
295 /* Not much left to do but to exit the thread, not the process. */
299 /* Nothing fancy, just call the function. */
300 result
= main (argc
, argv
, __environ MAIN_AUXVEC_PARAM
);