1 | /* Copyright (C) 2002-2018 Free Software Foundation, Inc. |
2 | This file is part of the GNU C Library. |
3 | Contributed by Ulrich Drepper <drepper@redhat.com>, 2002. |
4 | |
5 | The GNU C Library is free software; you can redistribute it and/or |
6 | modify it under the terms of the GNU Lesser General Public |
7 | License as published by the Free Software Foundation; either |
8 | version 2.1 of the License, or (at your option) any later version. |
9 | |
10 | The GNU C Library is distributed in the hope that it will be useful, |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
13 | Lesser General Public License for more details. |
14 | |
15 | You should have received a copy of the GNU Lesser General Public |
16 | License along with the GNU C Library; if not, see |
17 | <http://www.gnu.org/licenses/>. */ |
18 | |
19 | #include <assert.h> |
20 | #include <errno.h> |
21 | #include <limits.h> |
22 | #include <signal.h> |
23 | #include <stdlib.h> |
24 | #include <unistd.h> |
25 | #include <sys/param.h> |
26 | #include <sys/resource.h> |
27 | #include <pthreadP.h> |
28 | #include <atomic.h> |
29 | #include <ldsodefs.h> |
30 | #include <tls.h> |
31 | #include <list.h> |
32 | #include <fork.h> |
33 | #include <version.h> |
34 | #include <shlib-compat.h> |
35 | #include <smp.h> |
36 | #include <lowlevellock.h> |
37 | #include <futex-internal.h> |
38 | #include <kernel-features.h> |
39 | #include <libc-pointer-arith.h> |
40 | #include <pthread-pids.h> |
41 | |
42 | #ifndef TLS_MULTIPLE_THREADS_IN_TCB |
43 | /* Pointer to the corresponding variable in libc. */ |
44 | int *__libc_multiple_threads_ptr attribute_hidden; |
45 | #endif |
46 | |
47 | /* Size and alignment of static TLS block. */ |
48 | size_t __static_tls_size; |
49 | size_t __static_tls_align_m1; |
50 | |
51 | #ifndef __ASSUME_SET_ROBUST_LIST |
52 | /* Negative if we do not have the system call and we can use it. */ |
53 | int __set_robust_list_avail; |
54 | # define set_robust_list_not_avail() \ |
55 | __set_robust_list_avail = -1 |
56 | #else |
57 | # define set_robust_list_not_avail() do { } while (0) |
58 | #endif |
59 | |
60 | #ifndef __ASSUME_FUTEX_CLOCK_REALTIME |
61 | /* Nonzero if we do not have FUTEX_CLOCK_REALTIME. */ |
62 | int __have_futex_clock_realtime; |
63 | # define __set_futex_clock_realtime() \ |
64 | __have_futex_clock_realtime = 1 |
65 | #else |
66 | #define __set_futex_clock_realtime() do { } while (0) |
67 | #endif |
68 | |
69 | /* Version of the library, used in libthread_db to detect mismatches. */ |
70 | static const char nptl_version[] __attribute_used__ = VERSION; |
71 | |
72 | |
73 | #ifdef SHARED |
74 | static |
75 | #else |
76 | extern |
77 | #endif |
78 | void __nptl_set_robust (struct pthread *); |
79 | |
80 | #ifdef SHARED |
81 | static const struct pthread_functions pthread_functions = |
82 | { |
83 | .ptr_pthread_attr_destroy = __pthread_attr_destroy, |
84 | # if SHLIB_COMPAT(libpthread, GLIBC_2_0, GLIBC_2_1) |
85 | .ptr___pthread_attr_init_2_0 = __pthread_attr_init_2_0, |
86 | # endif |
87 | .ptr___pthread_attr_init_2_1 = __pthread_attr_init_2_1, |
88 | .ptr_pthread_attr_getdetachstate = __pthread_attr_getdetachstate, |
89 | .ptr_pthread_attr_setdetachstate = __pthread_attr_setdetachstate, |
90 | .ptr_pthread_attr_getinheritsched = __pthread_attr_getinheritsched, |
91 | .ptr_pthread_attr_setinheritsched = __pthread_attr_setinheritsched, |
92 | .ptr_pthread_attr_getschedparam = __pthread_attr_getschedparam, |
93 | .ptr_pthread_attr_setschedparam = __pthread_attr_setschedparam, |
94 | .ptr_pthread_attr_getschedpolicy = __pthread_attr_getschedpolicy, |
95 | .ptr_pthread_attr_setschedpolicy = __pthread_attr_setschedpolicy, |
96 | .ptr_pthread_attr_getscope = __pthread_attr_getscope, |
97 | .ptr_pthread_attr_setscope = __pthread_attr_setscope, |
98 | .ptr_pthread_condattr_destroy = __pthread_condattr_destroy, |
99 | .ptr_pthread_condattr_init = __pthread_condattr_init, |
100 | .ptr___pthread_cond_broadcast = __pthread_cond_broadcast, |
101 | .ptr___pthread_cond_destroy = __pthread_cond_destroy, |
102 | .ptr___pthread_cond_init = __pthread_cond_init, |
103 | .ptr___pthread_cond_signal = __pthread_cond_signal, |
104 | .ptr___pthread_cond_wait = __pthread_cond_wait, |
105 | .ptr___pthread_cond_timedwait = __pthread_cond_timedwait, |
106 | # if SHLIB_COMPAT(libpthread, GLIBC_2_0, GLIBC_2_3_2) |
107 | .ptr___pthread_cond_broadcast_2_0 = __pthread_cond_broadcast_2_0, |
108 | .ptr___pthread_cond_destroy_2_0 = __pthread_cond_destroy_2_0, |
109 | .ptr___pthread_cond_init_2_0 = __pthread_cond_init_2_0, |
110 | .ptr___pthread_cond_signal_2_0 = __pthread_cond_signal_2_0, |
111 | .ptr___pthread_cond_wait_2_0 = __pthread_cond_wait_2_0, |
112 | .ptr___pthread_cond_timedwait_2_0 = __pthread_cond_timedwait_2_0, |
113 | # endif |
114 | .ptr_pthread_equal = __pthread_equal, |
115 | .ptr___pthread_exit = __pthread_exit, |
116 | .ptr_pthread_getschedparam = __pthread_getschedparam, |
117 | .ptr_pthread_setschedparam = __pthread_setschedparam, |
118 | .ptr_pthread_mutex_destroy = __pthread_mutex_destroy, |
119 | .ptr_pthread_mutex_init = __pthread_mutex_init, |
120 | .ptr_pthread_mutex_lock = __pthread_mutex_lock, |
121 | .ptr_pthread_mutex_unlock = __pthread_mutex_unlock, |
122 | .ptr___pthread_setcancelstate = __pthread_setcancelstate, |
123 | .ptr_pthread_setcanceltype = __pthread_setcanceltype, |
124 | .ptr___pthread_cleanup_upto = __pthread_cleanup_upto, |
125 | .ptr___pthread_once = __pthread_once, |
126 | .ptr___pthread_rwlock_rdlock = __pthread_rwlock_rdlock, |
127 | .ptr___pthread_rwlock_wrlock = __pthread_rwlock_wrlock, |
128 | .ptr___pthread_rwlock_unlock = __pthread_rwlock_unlock, |
129 | .ptr___pthread_key_create = __pthread_key_create, |
130 | .ptr___pthread_getspecific = __pthread_getspecific, |
131 | .ptr___pthread_setspecific = __pthread_setspecific, |
132 | .ptr__pthread_cleanup_push_defer = __pthread_cleanup_push_defer, |
133 | .ptr__pthread_cleanup_pop_restore = __pthread_cleanup_pop_restore, |
134 | .ptr_nthreads = &__nptl_nthreads, |
135 | .ptr___pthread_unwind = &__pthread_unwind, |
136 | .ptr__nptl_deallocate_tsd = __nptl_deallocate_tsd, |
137 | # ifdef SIGSETXID |
138 | .ptr__nptl_setxid = __nptl_setxid, |
139 | # endif |
140 | .ptr_set_robust = __nptl_set_robust |
141 | }; |
142 | # define ptr_pthread_functions &pthread_functions |
143 | #else |
144 | # define ptr_pthread_functions NULL |
145 | #endif |
146 | |
147 | |
148 | #ifdef SHARED |
149 | static |
150 | #endif |
151 | void |
152 | __nptl_set_robust (struct pthread *self) |
153 | { |
154 | #ifdef __NR_set_robust_list |
155 | INTERNAL_SYSCALL_DECL (err); |
156 | INTERNAL_SYSCALL (set_robust_list, err, 2, &self->robust_head, |
157 | sizeof (struct robust_list_head)); |
158 | #endif |
159 | } |
160 | |
161 | |
162 | #ifdef SIGCANCEL |
163 | /* For asynchronous cancellation we use a signal. This is the handler. */ |
164 | static void |
165 | sigcancel_handler (int sig, siginfo_t *si, void *ctx) |
166 | { |
167 | /* Safety check. It would be possible to call this function for |
168 | other signals and send a signal from another process. This is not |
169 | correct and might even be a security problem. Try to catch as |
170 | many incorrect invocations as possible. */ |
171 | if (sig != SIGCANCEL |
172 | || si->si_pid != __getpid() |
173 | || si->si_code != SI_TKILL) |
174 | return; |
175 | |
176 | struct pthread *self = THREAD_SELF; |
177 | |
178 | int oldval = THREAD_GETMEM (self, cancelhandling); |
179 | while (1) |
180 | { |
181 | /* We are canceled now. When canceled by another thread this flag |
182 | is already set but if the signal is directly send (internally or |
183 | from another process) is has to be done here. */ |
184 | int newval = oldval | CANCELING_BITMASK | CANCELED_BITMASK; |
185 | |
186 | if (oldval == newval || (oldval & EXITING_BITMASK) != 0) |
187 | /* Already canceled or exiting. */ |
188 | break; |
189 | |
190 | int curval = THREAD_ATOMIC_CMPXCHG_VAL (self, cancelhandling, newval, |
191 | oldval); |
192 | if (curval == oldval) |
193 | { |
194 | /* Set the return value. */ |
195 | THREAD_SETMEM (self, result, PTHREAD_CANCELED); |
196 | |
197 | /* Make sure asynchronous cancellation is still enabled. */ |
198 | if ((newval & CANCELTYPE_BITMASK) != 0) |
199 | /* Run the registered destructors and terminate the thread. */ |
200 | __do_cancel (); |
201 | |
202 | break; |
203 | } |
204 | |
205 | oldval = curval; |
206 | } |
207 | } |
208 | #endif |
209 | |
210 | |
211 | #ifdef SIGSETXID |
212 | struct xid_command *__xidcmd attribute_hidden; |
213 | |
214 | /* We use the SIGSETXID signal in the setuid, setgid, etc. implementations to |
215 | tell each thread to call the respective setxid syscall on itself. This is |
216 | the handler. */ |
217 | static void |
218 | sighandler_setxid (int sig, siginfo_t *si, void *ctx) |
219 | { |
220 | int result; |
221 | |
222 | /* Safety check. It would be possible to call this function for |
223 | other signals and send a signal from another process. This is not |
224 | correct and might even be a security problem. Try to catch as |
225 | many incorrect invocations as possible. */ |
226 | if (sig != SIGSETXID |
227 | || si->si_pid != __getpid () |
228 | || si->si_code != SI_TKILL) |
229 | return; |
230 | |
231 | INTERNAL_SYSCALL_DECL (err); |
232 | result = INTERNAL_SYSCALL_NCS (__xidcmd->syscall_no, err, 3, __xidcmd->id[0], |
233 | __xidcmd->id[1], __xidcmd->id[2]); |
234 | int error = 0; |
235 | if (__glibc_unlikely (INTERNAL_SYSCALL_ERROR_P (result, err))) |
236 | error = INTERNAL_SYSCALL_ERRNO (result, err); |
237 | __nptl_setxid_error (__xidcmd, error); |
238 | |
239 | /* Reset the SETXID flag. */ |
240 | struct pthread *self = THREAD_SELF; |
241 | int flags, newval; |
242 | do |
243 | { |
244 | flags = THREAD_GETMEM (self, cancelhandling); |
245 | newval = THREAD_ATOMIC_CMPXCHG_VAL (self, cancelhandling, |
246 | flags & ~SETXID_BITMASK, flags); |
247 | } |
248 | while (flags != newval); |
249 | |
250 | /* And release the futex. */ |
251 | self->setxid_futex = 1; |
252 | futex_wake (&self->setxid_futex, 1, FUTEX_PRIVATE); |
253 | |
254 | if (atomic_decrement_val (&__xidcmd->cntr) == 0) |
255 | futex_wake ((unsigned int *) &__xidcmd->cntr, 1, FUTEX_PRIVATE); |
256 | } |
257 | #endif |
258 | |
259 | |
260 | /* When using __thread for this, we do it in libc so as not |
261 | to give libpthread its own TLS segment just for this. */ |
262 | extern void **__libc_dl_error_tsd (void) __attribute__ ((const)); |
263 | |
264 | |
265 | /* This can be set by the debugger before initialization is complete. */ |
266 | static bool __nptl_initial_report_events __attribute_used__; |
267 | |
268 | void |
269 | __pthread_initialize_minimal_internal (void) |
270 | { |
271 | /* Minimal initialization of the thread descriptor. */ |
272 | struct pthread *pd = THREAD_SELF; |
273 | __pthread_initialize_pids (pd); |
274 | THREAD_SETMEM (pd, specific[0], &pd->specific_1stblock[0]); |
275 | THREAD_SETMEM (pd, user_stack, true); |
276 | if (LLL_LOCK_INITIALIZER != 0) |
277 | THREAD_SETMEM (pd, lock, LLL_LOCK_INITIALIZER); |
278 | #if HP_TIMING_AVAIL |
279 | THREAD_SETMEM (pd, cpuclock_offset, GL(dl_cpuclock_offset)); |
280 | #endif |
281 | |
282 | /* Initialize the robust mutex data. */ |
283 | { |
284 | #if __PTHREAD_MUTEX_HAVE_PREV |
285 | pd->robust_prev = &pd->robust_head; |
286 | #endif |
287 | pd->robust_head.list = &pd->robust_head; |
288 | #ifdef __NR_set_robust_list |
289 | pd->robust_head.futex_offset = (offsetof (pthread_mutex_t, __data.__lock) |
290 | - offsetof (pthread_mutex_t, |
291 | __data.__list.__next)); |
292 | INTERNAL_SYSCALL_DECL (err); |
293 | int res = INTERNAL_SYSCALL (set_robust_list, err, 2, &pd->robust_head, |
294 | sizeof (struct robust_list_head)); |
295 | if (INTERNAL_SYSCALL_ERROR_P (res, err)) |
296 | #endif |
297 | set_robust_list_not_avail (); |
298 | } |
299 | |
300 | #ifdef __NR_futex |
301 | # ifndef __ASSUME_FUTEX_CLOCK_REALTIME |
302 | { |
303 | int word = 0; |
304 | /* NB: the syscall actually takes six parameters. The last is the |
305 | bit mask. But since we will not actually wait at all the value |
306 | is irrelevant. Given that passing six parameters is difficult |
307 | on some architectures we just pass whatever random value the |
308 | calling convention calls for to the kernel. It causes no harm. */ |
309 | INTERNAL_SYSCALL_DECL (err); |
310 | word = INTERNAL_SYSCALL (futex, err, 5, &word, |
311 | FUTEX_WAIT_BITSET | FUTEX_CLOCK_REALTIME |
312 | | FUTEX_PRIVATE_FLAG, 1, NULL, 0); |
313 | assert (INTERNAL_SYSCALL_ERROR_P (word, err)); |
314 | if (INTERNAL_SYSCALL_ERRNO (word, err) != ENOSYS) |
315 | __set_futex_clock_realtime (); |
316 | } |
317 | # endif |
318 | #endif |
319 | |
320 | /* Set initial thread's stack block from 0 up to __libc_stack_end. |
321 | It will be bigger than it actually is, but for unwind.c/pt-longjmp.c |
322 | purposes this is good enough. */ |
323 | THREAD_SETMEM (pd, stackblock_size, (size_t) __libc_stack_end); |
324 | |
325 | /* Initialize the list of all running threads with the main thread. */ |
326 | INIT_LIST_HEAD (&__stack_user); |
327 | list_add (&pd->list, &__stack_user); |
328 | |
329 | /* Before initializing __stack_user, the debugger could not find us and |
330 | had to set __nptl_initial_report_events. Propagate its setting. */ |
331 | THREAD_SETMEM (pd, report_events, __nptl_initial_report_events); |
332 | |
333 | #if defined SIGCANCEL || defined SIGSETXID |
334 | struct sigaction sa; |
335 | __sigemptyset (&sa.sa_mask); |
336 | |
337 | # ifdef SIGCANCEL |
338 | /* Install the cancellation signal handler. If for some reason we |
339 | cannot install the handler we do not abort. Maybe we should, but |
340 | it is only asynchronous cancellation which is affected. */ |
341 | sa.sa_sigaction = sigcancel_handler; |
342 | sa.sa_flags = SA_SIGINFO; |
343 | (void) __libc_sigaction (SIGCANCEL, &sa, NULL); |
344 | # endif |
345 | |
346 | # ifdef SIGSETXID |
347 | /* Install the handle to change the threads' uid/gid. */ |
348 | sa.sa_sigaction = sighandler_setxid; |
349 | sa.sa_flags = SA_SIGINFO | SA_RESTART; |
350 | (void) __libc_sigaction (SIGSETXID, &sa, NULL); |
351 | # endif |
352 | |
353 | /* The parent process might have left the signals blocked. Just in |
354 | case, unblock it. We reuse the signal mask in the sigaction |
355 | structure. It is already cleared. */ |
356 | # ifdef SIGCANCEL |
357 | __sigaddset (&sa.sa_mask, SIGCANCEL); |
358 | # endif |
359 | # ifdef SIGSETXID |
360 | __sigaddset (&sa.sa_mask, SIGSETXID); |
361 | # endif |
362 | { |
363 | INTERNAL_SYSCALL_DECL (err); |
364 | (void) INTERNAL_SYSCALL (rt_sigprocmask, err, 4, SIG_UNBLOCK, &sa.sa_mask, |
365 | NULL, _NSIG / 8); |
366 | } |
367 | #endif |
368 | |
369 | /* Get the size of the static and alignment requirements for the TLS |
370 | block. */ |
371 | size_t static_tls_align; |
372 | _dl_get_tls_static_info (&__static_tls_size, &static_tls_align); |
373 | |
374 | /* Make sure the size takes all the alignments into account. */ |
375 | if (STACK_ALIGN > static_tls_align) |
376 | static_tls_align = STACK_ALIGN; |
377 | __static_tls_align_m1 = static_tls_align - 1; |
378 | |
379 | __static_tls_size = roundup (__static_tls_size, static_tls_align); |
380 | |
381 | /* Determine the default allowed stack size. This is the size used |
382 | in case the user does not specify one. */ |
383 | struct rlimit limit; |
384 | if (__getrlimit (RLIMIT_STACK, &limit) != 0 |
385 | || limit.rlim_cur == RLIM_INFINITY) |
386 | /* The system limit is not usable. Use an architecture-specific |
387 | default. */ |
388 | limit.rlim_cur = ARCH_STACK_DEFAULT_SIZE; |
389 | else if (limit.rlim_cur < PTHREAD_STACK_MIN) |
390 | /* The system limit is unusably small. |
391 | Use the minimal size acceptable. */ |
392 | limit.rlim_cur = PTHREAD_STACK_MIN; |
393 | |
394 | /* Make sure it meets the minimum size that allocate_stack |
395 | (allocatestack.c) will demand, which depends on the page size. */ |
396 | const uintptr_t pagesz = GLRO(dl_pagesize); |
397 | const size_t minstack = pagesz + __static_tls_size + MINIMAL_REST_STACK; |
398 | if (limit.rlim_cur < minstack) |
399 | limit.rlim_cur = minstack; |
400 | |
401 | /* Round the resource limit up to page size. */ |
402 | limit.rlim_cur = ALIGN_UP (limit.rlim_cur, pagesz); |
403 | lll_lock (__default_pthread_attr_lock, LLL_PRIVATE); |
404 | __default_pthread_attr.stacksize = limit.rlim_cur; |
405 | __default_pthread_attr.guardsize = GLRO (dl_pagesize); |
406 | lll_unlock (__default_pthread_attr_lock, LLL_PRIVATE); |
407 | |
408 | #ifdef SHARED |
409 | /* Make __rtld_lock_{,un}lock_recursive use pthread_mutex_{,un}lock, |
410 | keep the lock count from the ld.so implementation. */ |
411 | GL(dl_rtld_lock_recursive) = (void *) __pthread_mutex_lock; |
412 | GL(dl_rtld_unlock_recursive) = (void *) __pthread_mutex_unlock; |
413 | unsigned int rtld_lock_count = GL(dl_load_lock).mutex.__data.__count; |
414 | GL(dl_load_lock).mutex.__data.__count = 0; |
415 | while (rtld_lock_count-- > 0) |
416 | __pthread_mutex_lock (&GL(dl_load_lock).mutex); |
417 | |
418 | GL(dl_make_stack_executable_hook) = &__make_stacks_executable; |
419 | #endif |
420 | |
421 | GL(dl_init_static_tls) = &__pthread_init_static_tls; |
422 | |
423 | GL(dl_wait_lookup_done) = &__wait_lookup_done; |
424 | |
425 | /* Register the fork generation counter with the libc. */ |
426 | #ifndef TLS_MULTIPLE_THREADS_IN_TCB |
427 | __libc_multiple_threads_ptr = |
428 | #endif |
429 | __libc_pthread_init (&__fork_generation, __reclaim_stacks, |
430 | ptr_pthread_functions); |
431 | |
432 | /* Determine whether the machine is SMP or not. */ |
433 | __is_smp = is_smp_system (); |
434 | } |
435 | strong_alias (__pthread_initialize_minimal_internal, |
436 | __pthread_initialize_minimal) |
437 | |
438 | |
439 | size_t |
440 | __pthread_get_minstack (const pthread_attr_t *attr) |
441 | { |
442 | return GLRO(dl_pagesize) + __static_tls_size + PTHREAD_STACK_MIN; |
443 | } |
444 | |