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
;
40 # ifndef THREAD_SET_POINTER_GUARD
41 /* Only exported for architectures that don't store the pointer guard
42 value in thread local area. */
43 uintptr_t __pointer_chk_guard_local
44 attribute_relro attribute_hidden
__attribute__ ((nocommon
));
48 #ifdef HAVE_PTR_NTHREADS
49 /* We need atomic operations. */
58 # ifdef ELF_MACHINE_IRELA
59 # define IREL_T ElfW(Rela)
60 # define IPLT_START __rela_iplt_start
61 # define IPLT_END __rela_iplt_end
62 # define IREL elf_irela
63 # elif defined ELF_MACHINE_IREL
64 # define IREL_T ElfW(Rel)
65 # define IPLT_START __rel_iplt_start
66 # define IPLT_END __rel_iplt_end
67 # define IREL elf_irel
74 /* We use weak references for these so that we'll still work with a linker
75 that doesn't define them. Such a linker doesn't support IFUNC at all
76 and so uses won't work, but a statically-linked program that doesn't
77 use any IFUNC symbols won't have a problem. */
78 extern const IREL_T IPLT_START
[] __attribute__ ((weak
));
79 extern const IREL_T IPLT_END
[] __attribute__ ((weak
));
80 for (const IREL_T
*ipltent
= IPLT_START
; ipltent
< IPLT_END
; ++ipltent
)
87 #ifdef LIBC_START_MAIN
88 # ifdef LIBC_START_DISABLE_INLINE
89 # define STATIC static
91 # define STATIC static inline __attribute__ ((always_inline))
95 # define LIBC_START_MAIN __libc_start_main
98 #ifdef MAIN_AUXVEC_ARG
99 /* main gets passed a pointer to the auxiliary. */
100 # define MAIN_AUXVEC_DECL , void *
101 # define MAIN_AUXVEC_PARAM , auxvec
103 # define MAIN_AUXVEC_DECL
104 # define MAIN_AUXVEC_PARAM
107 STATIC
int LIBC_START_MAIN (int (*main
) (int, char **, char **
111 #ifdef LIBC_START_MAIN_AUXVEC_ARG
112 ElfW(auxv_t
) *auxvec
,
114 __typeof (main
) init
,
116 void (*rtld_fini
) (void),
118 __attribute__ ((noreturn
));
121 /* Note: the fini parameter is ignored here for shared library. It
122 is registered with __cxa_atexit. This had the disadvantage that
123 finalizers were called in more than one place. */
125 LIBC_START_MAIN (int (*main
) (int, char **, char ** MAIN_AUXVEC_DECL
),
126 int argc
, char **argv
,
127 #ifdef LIBC_START_MAIN_AUXVEC_ARG
128 ElfW(auxv_t
) *auxvec
,
130 __typeof (main
) init
,
132 void (*rtld_fini
) (void), void *stack_end
)
134 /* Result of the 'main' function. */
137 __libc_multiple_libcs
= &_dl_starting_up
&& !_dl_starting_up
;
140 char **ev
= &argv
[argc
+ 1];
144 /* Store the lowest stack address. This is done in ld.so if this is
145 the code for the DSO. */
146 __libc_stack_end
= stack_end
;
148 # ifdef HAVE_AUX_VECTOR
149 /* First process the auxiliary vector since we need to find the
150 program header to locate an eventually present PT_TLS entry. */
151 # ifndef LIBC_START_MAIN_AUXVEC_ARG
152 ElfW(auxv_t
) *auxvec
;
155 while (*evp
++ != NULL
)
157 auxvec
= (ElfW(auxv_t
) *) evp
;
160 _dl_aux_init (auxvec
);
161 if (GL(dl_phdr
) == NULL
)
164 /* Starting from binutils-2.23, the linker will define the
165 magic symbol __ehdr_start to point to our own ELF header
166 if it is visible in a segment that also includes the phdrs.
167 So we can set up _dl_phdr and _dl_phnum even without any
168 information from auxv. */
170 extern const ElfW(Ehdr
) __ehdr_start
171 __attribute__ ((weak
, visibility ("hidden")));
172 if (&__ehdr_start
!= NULL
)
174 assert (__ehdr_start
.e_phentsize
== sizeof *GL(dl_phdr
));
175 GL(dl_phdr
) = (const void *) &__ehdr_start
+ __ehdr_start
.e_phoff
;
176 GL(dl_phnum
) = __ehdr_start
.e_phnum
;
180 # ifdef DL_SYSDEP_OSCHECK
181 if (!__libc_multiple_libcs
)
183 /* This needs to run to initiliaze _dl_osversion before TLS
184 setup might check it. */
185 DL_SYSDEP_OSCHECK (__libc_fatal
);
189 /* Perform IREL{,A} relocations. */
192 /* Initialize the thread library at least a bit since the libgcc
193 functions are using thread functions if these are available and
194 we need to setup errno. */
195 __pthread_initialize_minimal ();
197 /* Set up the stack checker's canary. */
198 uintptr_t stack_chk_guard
= _dl_setup_stack_chk_guard (_dl_random
);
199 # ifdef THREAD_SET_STACK_GUARD
200 THREAD_SET_STACK_GUARD (stack_chk_guard
);
202 __stack_chk_guard
= stack_chk_guard
;
205 /* Set up the pointer guard value. */
206 uintptr_t pointer_chk_guard
= _dl_setup_pointer_guard (_dl_random
,
208 # ifdef THREAD_SET_POINTER_GUARD
209 THREAD_SET_POINTER_GUARD (pointer_chk_guard
);
211 __pointer_chk_guard_local
= pointer_chk_guard
;
216 /* Register the destructor of the dynamic linker if there is any. */
217 if (__builtin_expect (rtld_fini
!= NULL
, 1))
218 __cxa_atexit ((void (*) (void *)) rtld_fini
, NULL
, NULL
);
221 /* Call the initializer of the libc. This is only needed here if we
222 are compiling for the static library in which case we haven't
223 run the constructors in `_dl_start_user'. */
224 __libc_init_first (argc
, argv
, __environ
);
226 /* Register the destructor of the program, if any. */
228 __cxa_atexit ((void (*) (void *)) fini
, NULL
, NULL
);
230 /* Some security at this point. Prevent starting a SUID binary where
231 the standard file descriptors are not opened. We have to do this
232 only for statically linked applications since otherwise the dynamic
233 loader did the work already. */
234 if (__builtin_expect (__libc_enable_secure
, 0))
235 __libc_check_standard_fds ();
238 /* Call the initializer of the program, if any. */
240 if (__builtin_expect (GLRO(dl_debug_mask
) & DL_DEBUG_IMPCALLS
, 0))
241 GLRO(dl_debug_printf
) ("\ninitialize program: %s\n\n", argv
[0]);
244 (*init
) (argc
, argv
, __environ MAIN_AUXVEC_PARAM
);
247 /* Auditing checkpoint: we have a new object. */
248 if (__builtin_expect (GLRO(dl_naudit
) > 0, 0))
250 struct audit_ifaces
*afct
= GLRO(dl_audit
);
251 struct link_map
*head
= GL(dl_ns
)[LM_ID_BASE
]._ns_loaded
;
252 for (unsigned int cnt
= 0; cnt
< GLRO(dl_naudit
); ++cnt
)
254 if (afct
->preinit
!= NULL
)
255 afct
->preinit (&head
->l_audit
[cnt
].cookie
);
263 if (__builtin_expect (GLRO(dl_debug_mask
) & DL_DEBUG_IMPCALLS
, 0))
264 GLRO(dl_debug_printf
) ("\ntransferring control: %s\n\n", argv
[0]);
267 #ifdef HAVE_CLEANUP_JMP_BUF
268 /* Memory for the cancellation buffer. */
269 struct pthread_unwind_buf unwind_buf
;
272 not_first_call
= setjmp ((struct __jmp_buf_tag
*) unwind_buf
.cancel_jmp_buf
);
273 if (__builtin_expect (! not_first_call
, 1))
275 struct pthread
*self
= THREAD_SELF
;
277 /* Store old info. */
278 unwind_buf
.priv
.data
.prev
= THREAD_GETMEM (self
, cleanup_jmp_buf
);
279 unwind_buf
.priv
.data
.cleanup
= THREAD_GETMEM (self
, cleanup
);
281 /* Store the new cleanup handler info. */
282 THREAD_SETMEM (self
, cleanup_jmp_buf
, &unwind_buf
);
284 /* Run the program. */
285 result
= main (argc
, argv
, __environ MAIN_AUXVEC_PARAM
);
289 /* Remove the thread-local data. */
291 PTHFCT_CALL (ptr__nptl_deallocate_tsd
, ());
293 extern void __nptl_deallocate_tsd (void) __attribute ((weak
));
294 __nptl_deallocate_tsd ();
297 /* One less thread. Decrement the counter. If it is zero we
298 terminate the entire process. */
301 unsigned int *ptr
= __libc_pthread_functions
.ptr_nthreads
;
306 extern unsigned int __nptl_nthreads
__attribute ((weak
));
307 unsigned int *const ptr
= &__nptl_nthreads
;
310 if (! atomic_decrement_and_test (ptr
))
311 /* Not much left to do but to exit the thread, not the process. */
315 /* Nothing fancy, just call the function. */
316 result
= main (argc
, argv
, __environ MAIN_AUXVEC_PARAM
);