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2b778ceb | 1 | /* Copyright (C) 1998-2021 Free Software Foundation, Inc. |
7dea968e UD |
2 | This file is part of the GNU C Library. |
3 | ||
4 | The GNU C Library is free software; you can redistribute it and/or | |
41bdb6e2 AJ |
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. | |
7dea968e UD |
8 | |
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 | |
41bdb6e2 | 12 | Lesser General Public License for more details. |
7dea968e | 13 | |
41bdb6e2 | 14 | You should have received a copy of the GNU Lesser General Public |
59ba27a6 | 15 | License along with the GNU C Library; if not, see |
5a82c748 | 16 | <https://www.gnu.org/licenses/>. */ |
7dea968e | 17 | |
47618209 SN |
18 | /* Mark symbols hidden in static PIE for early self relocation to work. */ |
19 | #if BUILD_PIE_DEFAULT | |
20 | # pragma GCC visibility push(hidden) | |
21 | #endif | |
288f7d79 | 22 | #include <assert.h> |
3db52d94 | 23 | #include <stdlib.h> |
dde2652b | 24 | #include <stdio.h> |
3db52d94 | 25 | #include <unistd.h> |
a42195db | 26 | #include <ldsodefs.h> |
e0db6517 | 27 | #include <exit-thread.h> |
2098d403 | 28 | #include <libc-diag.h> |
67e58f39 | 29 | #include <libc-internal.h> |
ec935dea | 30 | #include <elf/libc-early-init.h> |
03e187a4 | 31 | #include <stdbool.h> |
67e58f39 SP |
32 | |
33 | #include <elf/dl-tunables.h> | |
3db52d94 | 34 | |
31161268 UD |
35 | extern void __libc_init_first (int argc, char **argv, char **envp); |
36 | ||
7ae4abe9 | 37 | #include <tls.h> |
4fb7a71f | 38 | #ifndef SHARED |
dde2652b | 39 | # include <dl-osinfo.h> |
35f1e827 UD |
40 | # ifndef THREAD_SET_STACK_GUARD |
41 | /* Only exported for architectures that don't store the stack guard canary | |
42 | in thread local area. */ | |
43 | uintptr_t __stack_chk_guard attribute_relro; | |
44 | # endif | |
c61b4d41 CD |
45 | # ifndef THREAD_SET_POINTER_GUARD |
46 | /* Only exported for architectures that don't store the pointer guard | |
47 | value in thread local area. */ | |
48 | uintptr_t __pointer_chk_guard_local | |
49 | attribute_relro attribute_hidden __attribute__ ((nocommon)); | |
50 | # endif | |
4fb7a71f AJ |
51 | #endif |
52 | ||
47202270 UD |
53 | #ifdef HAVE_PTR_NTHREADS |
54 | /* We need atomic operations. */ | |
55 | # include <atomic.h> | |
56 | #endif | |
57 | ||
17427edd | 58 | |
21ad0558 RM |
59 | #ifndef SHARED |
60 | # include <link.h> | |
61 | # include <dl-irel.h> | |
62 | ||
63 | # ifdef ELF_MACHINE_IRELA | |
64 | # define IREL_T ElfW(Rela) | |
65 | # define IPLT_START __rela_iplt_start | |
66 | # define IPLT_END __rela_iplt_end | |
67 | # define IREL elf_irela | |
68 | # elif defined ELF_MACHINE_IREL | |
69 | # define IREL_T ElfW(Rel) | |
70 | # define IPLT_START __rel_iplt_start | |
71 | # define IPLT_END __rel_iplt_end | |
72 | # define IREL elf_irel | |
73 | # endif | |
74 | ||
21ad0558 RM |
75 | static void |
76 | apply_irel (void) | |
77 | { | |
35a5b08b RM |
78 | # ifdef IREL |
79 | /* We use weak references for these so that we'll still work with a linker | |
80 | that doesn't define them. Such a linker doesn't support IFUNC at all | |
81 | and so uses won't work, but a statically-linked program that doesn't | |
82 | use any IFUNC symbols won't have a problem. */ | |
83 | extern const IREL_T IPLT_START[] __attribute__ ((weak)); | |
84 | extern const IREL_T IPLT_END[] __attribute__ ((weak)); | |
21ad0558 RM |
85 | for (const IREL_T *ipltent = IPLT_START; ipltent < IPLT_END; ++ipltent) |
86 | IREL (ipltent); | |
35a5b08b | 87 | # endif |
21ad0558 RM |
88 | } |
89 | #endif | |
90 | ||
91 | ||
2b089f21 | 92 | #ifdef LIBC_START_MAIN |
11986c68 UD |
93 | # ifdef LIBC_START_DISABLE_INLINE |
94 | # define STATIC static | |
95 | # else | |
96 | # define STATIC static inline __attribute__ ((always_inline)) | |
97 | # endif | |
2b089f21 RM |
98 | #else |
99 | # define STATIC | |
e97ed6dd | 100 | # define LIBC_START_MAIN __libc_start_main |
2b089f21 RM |
101 | #endif |
102 | ||
2b089f21 | 103 | #ifdef MAIN_AUXVEC_ARG |
09d65ff3 UD |
104 | /* main gets passed a pointer to the auxiliary. */ |
105 | # define MAIN_AUXVEC_DECL , void * | |
106 | # define MAIN_AUXVEC_PARAM , auxvec | |
107 | #else | |
108 | # define MAIN_AUXVEC_DECL | |
109 | # define MAIN_AUXVEC_PARAM | |
2b089f21 RM |
110 | #endif |
111 | ||
4158ba08 SP |
112 | #ifndef ARCH_INIT_CPU_FEATURES |
113 | # define ARCH_INIT_CPU_FEATURES() | |
114 | #endif | |
115 | ||
91ac3a7d TMQMF |
116 | #include <libc-start.h> |
117 | ||
09d65ff3 UD |
118 | STATIC int LIBC_START_MAIN (int (*main) (int, char **, char ** |
119 | MAIN_AUXVEC_DECL), | |
2b089f21 | 120 | int argc, |
70d9946a | 121 | char **argv, |
2b089f21 | 122 | #ifdef LIBC_START_MAIN_AUXVEC_ARG |
70d9946a | 123 | ElfW(auxv_t) *auxvec, |
2b089f21 | 124 | #endif |
2b089f21 | 125 | __typeof (main) init, |
2b089f21 RM |
126 | void (*fini) (void), |
127 | void (*rtld_fini) (void), | |
70d9946a | 128 | void *stack_end) |
17427edd | 129 | __attribute__ ((noreturn)); |
a828c2f5 | 130 | |
9dcafc55 | 131 | |
43c59a70 UD |
132 | /* Note: the fini parameter is ignored here for shared library. It |
133 | is registered with __cxa_atexit. This had the disadvantage that | |
134 | finalizers were called in more than one place. */ | |
2b089f21 | 135 | STATIC int |
09d65ff3 | 136 | LIBC_START_MAIN (int (*main) (int, char **, char ** MAIN_AUXVEC_DECL), |
70d9946a | 137 | int argc, char **argv, |
2b089f21 | 138 | #ifdef LIBC_START_MAIN_AUXVEC_ARG |
70d9946a | 139 | ElfW(auxv_t) *auxvec, |
2b089f21 | 140 | #endif |
2b089f21 | 141 | __typeof (main) init, |
2b089f21 | 142 | void (*fini) (void), |
70d9946a | 143 | void (*rtld_fini) (void), void *stack_end) |
7dea968e | 144 | { |
7ae4abe9 UD |
145 | /* Result of the 'main' function. */ |
146 | int result; | |
147 | ||
3fb2606a | 148 | #ifndef SHARED |
9d7a3741 L |
149 | _dl_relocate_static_pie (); |
150 | ||
70d9946a | 151 | char **ev = &argv[argc + 1]; |
4f657581 | 152 | |
70d9946a | 153 | __environ = ev; |
ab95290c | 154 | |
ea4f25a7 UD |
155 | /* Store the lowest stack address. This is done in ld.so if this is |
156 | the code for the DSO. */ | |
c0fb8a56 | 157 | __libc_stack_end = stack_end; |
31161268 | 158 | |
8a30f00f UD |
159 | # ifdef HAVE_AUX_VECTOR |
160 | /* First process the auxiliary vector since we need to find the | |
161 | program header to locate an eventually present PT_TLS entry. */ | |
2b089f21 | 162 | # ifndef LIBC_START_MAIN_AUXVEC_ARG |
70d9946a | 163 | ElfW(auxv_t) *auxvec; |
2b089f21 | 164 | { |
70d9946a | 165 | char **evp = ev; |
97026947 UD |
166 | while (*evp++ != NULL) |
167 | ; | |
70d9946a | 168 | auxvec = (ElfW(auxv_t) *) evp; |
2b089f21 RM |
169 | } |
170 | # endif | |
171 | _dl_aux_init (auxvec); | |
288f7d79 | 172 | if (GL(dl_phdr) == NULL) |
8a30f00f | 173 | # endif |
288f7d79 RM |
174 | { |
175 | /* Starting from binutils-2.23, the linker will define the | |
176 | magic symbol __ehdr_start to point to our own ELF header | |
177 | if it is visible in a segment that also includes the phdrs. | |
178 | So we can set up _dl_phdr and _dl_phnum even without any | |
179 | information from auxv. */ | |
180 | ||
ae9552cf | 181 | extern const ElfW(Ehdr) __ehdr_start |
04af1eb3 SN |
182 | # if BUILD_PIE_DEFAULT |
183 | __attribute__ ((visibility ("hidden"))); | |
184 | # else | |
ae9552cf | 185 | __attribute__ ((weak, visibility ("hidden"))); |
288f7d79 | 186 | if (&__ehdr_start != NULL) |
04af1eb3 | 187 | # endif |
288f7d79 RM |
188 | { |
189 | assert (__ehdr_start.e_phentsize == sizeof *GL(dl_phdr)); | |
190 | GL(dl_phdr) = (const void *) &__ehdr_start + __ehdr_start.e_phoff; | |
191 | GL(dl_phnum) = __ehdr_start.e_phnum; | |
192 | } | |
193 | } | |
194 | ||
67e58f39 SP |
195 | /* Initialize very early so that tunables can use it. */ |
196 | __libc_init_secure (); | |
197 | ||
198 | __tunables_init (__environ); | |
199 | ||
4158ba08 SP |
200 | ARCH_INIT_CPU_FEATURES (); |
201 | ||
21ad0558 | 202 | /* Perform IREL{,A} relocations. */ |
91ac3a7d | 203 | ARCH_SETUP_IREL (); |
1c3c269b | 204 | |
003a27e8 | 205 | /* The stack guard goes into the TCB, so initialize it early. */ |
bcfa607b | 206 | ARCH_SETUP_TLS (); |
a828c2f5 | 207 | |
91ac3a7d TMQMF |
208 | /* In some architectures, IREL{,A} relocations happen after TLS setup in |
209 | order to let IFUNC resolvers benefit from TCB information, e.g. powerpc's | |
210 | hwcap and platform fields available in the TCB. */ | |
211 | ARCH_APPLY_IREL (); | |
212 | ||
35f1e827 | 213 | /* Set up the stack checker's canary. */ |
5b656a0d | 214 | uintptr_t stack_chk_guard = _dl_setup_stack_chk_guard (_dl_random); |
75fb247e | 215 | # ifdef THREAD_SET_STACK_GUARD |
35f1e827 | 216 | THREAD_SET_STACK_GUARD (stack_chk_guard); |
75fb247e | 217 | # else |
35f1e827 | 218 | __stack_chk_guard = stack_chk_guard; |
75fb247e | 219 | # endif |
c61b4d41 | 220 | |
003a27e8 | 221 | # ifdef DL_SYSDEP_OSCHECK |
e7570f41 FW |
222 | { |
223 | /* This needs to run to initiliaze _dl_osversion before TLS | |
224 | setup might check it. */ | |
225 | DL_SYSDEP_OSCHECK (__libc_fatal); | |
226 | } | |
003a27e8 NA |
227 | # endif |
228 | ||
229 | /* Initialize libpthread if linked in. */ | |
230 | if (__pthread_initialize_minimal != NULL) | |
231 | __pthread_initialize_minimal (); | |
232 | ||
c61b4d41 CD |
233 | /* Set up the pointer guard value. */ |
234 | uintptr_t pointer_chk_guard = _dl_setup_pointer_guard (_dl_random, | |
235 | stack_chk_guard); | |
236 | # ifdef THREAD_SET_POINTER_GUARD | |
237 | THREAD_SET_POINTER_GUARD (pointer_chk_guard); | |
238 | # else | |
239 | __pointer_chk_guard_local = pointer_chk_guard; | |
240 | # endif | |
241 | ||
91ac3a7d | 242 | #endif /* !SHARED */ |
75fb247e | 243 | |
3db52d94 | 244 | /* Register the destructor of the dynamic linker if there is any. */ |
a1ffb40e | 245 | if (__glibc_likely (rtld_fini != NULL)) |
c08bc50a | 246 | __cxa_atexit ((void (*) (void *)) rtld_fini, NULL, NULL); |
3db52d94 | 247 | |
43c59a70 | 248 | #ifndef SHARED |
ec935dea FW |
249 | /* Perform early initialization. In the shared case, this function |
250 | is called from the dynamic loader as early as possible. */ | |
03e187a4 | 251 | __libc_early_init (true); |
ec935dea | 252 | |
dacc8ffa UD |
253 | /* Call the initializer of the libc. This is only needed here if we |
254 | are compiling for the static library in which case we haven't | |
255 | run the constructors in `_dl_start_user'. */ | |
31161268 UD |
256 | __libc_init_first (argc, argv, __environ); |
257 | ||
43c59a70 UD |
258 | /* Register the destructor of the program, if any. */ |
259 | if (fini) | |
260 | __cxa_atexit ((void (*) (void *)) fini, NULL, NULL); | |
261 | ||
9946f75a UD |
262 | /* Some security at this point. Prevent starting a SUID binary where |
263 | the standard file descriptors are not opened. We have to do this | |
264 | only for statically linked applications since otherwise the dynamic | |
265 | loader did the work already. */ | |
266 | if (__builtin_expect (__libc_enable_secure, 0)) | |
267 | __libc_check_standard_fds (); | |
268 | #endif | |
269 | ||
4194bc66 | 270 | /* Call the initializer of the program, if any. */ |
b5567b2a | 271 | #ifdef SHARED |
afdca0f2 | 272 | if (__builtin_expect (GLRO(dl_debug_mask) & DL_DEBUG_IMPCALLS, 0)) |
154d10bd | 273 | GLRO(dl_debug_printf) ("\ninitialize program: %s\n\n", argv[0]); |
31161268 | 274 | #endif |
4194bc66 | 275 | if (init) |
04395c90 | 276 | (*init) (argc, argv, __environ MAIN_AUXVEC_PARAM); |
3db52d94 | 277 | |
9dcafc55 UD |
278 | #ifdef SHARED |
279 | /* Auditing checkpoint: we have a new object. */ | |
a1ffb40e | 280 | if (__glibc_unlikely (GLRO(dl_naudit) > 0)) |
9dcafc55 UD |
281 | { |
282 | struct audit_ifaces *afct = GLRO(dl_audit); | |
283 | struct link_map *head = GL(dl_ns)[LM_ID_BASE]._ns_loaded; | |
284 | for (unsigned int cnt = 0; cnt < GLRO(dl_naudit); ++cnt) | |
285 | { | |
286 | if (afct->preinit != NULL) | |
e1d559f3 | 287 | afct->preinit (&link_map_audit_state (head, cnt)->cookie); |
9dcafc55 UD |
288 | |
289 | afct = afct->next; | |
290 | } | |
291 | } | |
292 | #endif | |
293 | ||
b5567b2a | 294 | #ifdef SHARED |
a1ffb40e | 295 | if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_IMPCALLS)) |
154d10bd | 296 | GLRO(dl_debug_printf) ("\ntransferring control: %s\n\n", argv[0]); |
31161268 UD |
297 | #endif |
298 | ||
f737dfd0 CD |
299 | #ifndef SHARED |
300 | _dl_debug_initialize (0, LM_ID_BASE); | |
301 | #endif | |
09d65ff3 UD |
302 | #ifdef HAVE_CLEANUP_JMP_BUF |
303 | /* Memory for the cancellation buffer. */ | |
304 | struct pthread_unwind_buf unwind_buf; | |
305 | ||
306 | int not_first_call; | |
2098d403 JM |
307 | DIAG_PUSH_NEEDS_COMMENT; |
308 | #if __GNUC_PREREQ (7, 0) | |
309 | /* This call results in a -Wstringop-overflow warning because struct | |
310 | pthread_unwind_buf is smaller than jmp_buf. setjmp and longjmp | |
311 | do not use anything beyond the common prefix (they never access | |
312 | the saved signal mask), so that is a false positive. */ | |
313 | DIAG_IGNORE_NEEDS_COMMENT (11, "-Wstringop-overflow="); | |
314 | #endif | |
09d65ff3 | 315 | not_first_call = setjmp ((struct __jmp_buf_tag *) unwind_buf.cancel_jmp_buf); |
2098d403 | 316 | DIAG_POP_NEEDS_COMMENT; |
a1ffb40e | 317 | if (__glibc_likely (! not_first_call)) |
7ae4abe9 | 318 | { |
09d65ff3 | 319 | struct pthread *self = THREAD_SELF; |
7ae4abe9 | 320 | |
09d65ff3 UD |
321 | /* Store old info. */ |
322 | unwind_buf.priv.data.prev = THREAD_GETMEM (self, cleanup_jmp_buf); | |
323 | unwind_buf.priv.data.cleanup = THREAD_GETMEM (self, cleanup); | |
2b089f21 | 324 | |
09d65ff3 UD |
325 | /* Store the new cleanup handler info. */ |
326 | THREAD_SETMEM (self, cleanup_jmp_buf, &unwind_buf); | |
327 | ||
328 | /* Run the program. */ | |
329 | result = main (argc, argv, __environ MAIN_AUXVEC_PARAM); | |
7ae4abe9 | 330 | } |
7ae4abe9 | 331 | else |
47202270 | 332 | { |
3fa21fd8 UD |
333 | /* Remove the thread-local data. */ |
334 | # ifdef SHARED | |
ea1533e0 | 335 | PTHFCT_CALL (ptr__nptl_deallocate_tsd, ()); |
3fa21fd8 UD |
336 | # else |
337 | extern void __nptl_deallocate_tsd (void) __attribute ((weak)); | |
338 | __nptl_deallocate_tsd (); | |
339 | # endif | |
340 | ||
47202270 UD |
341 | /* One less thread. Decrement the counter. If it is zero we |
342 | terminate the entire process. */ | |
343 | result = 0; | |
09d65ff3 | 344 | # ifdef SHARED |
ea1533e0 | 345 | unsigned int *ptr = __libc_pthread_functions.ptr_nthreads; |
e10bb107 | 346 | # ifdef PTR_DEMANGLE |
ea1533e0 | 347 | PTR_DEMANGLE (ptr); |
e10bb107 | 348 | # endif |
09d65ff3 | 349 | # else |
9cfe5381 RM |
350 | extern unsigned int __nptl_nthreads __attribute ((weak)); |
351 | unsigned int *const ptr = &__nptl_nthreads; | |
09d65ff3 | 352 | # endif |
47202270 UD |
353 | |
354 | if (! atomic_decrement_and_test (ptr)) | |
47202270 | 355 | /* Not much left to do but to exit the thread, not the process. */ |
e0db6517 | 356 | __exit_thread (); |
47202270 | 357 | } |
09d65ff3 UD |
358 | #else |
359 | /* Nothing fancy, just call the function. */ | |
360 | result = main (argc, argv, __environ MAIN_AUXVEC_PARAM); | |
7ae4abe9 UD |
361 | #endif |
362 | ||
363 | exit (result); | |
7dea968e | 364 | } |