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d614a753 | 1 | /* Copyright (C) 2002-2020 Free Software Foundation, Inc. |
76a50749 UD |
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 | |
59ba27a6 | 16 | License along with the GNU C Library; if not, see |
5a82c748 | 17 | <https://www.gnu.org/licenses/>. */ |
76a50749 | 18 | |
fd5bdc09 | 19 | #include <ctype.h> |
76a50749 UD |
20 | #include <errno.h> |
21 | #include <stdbool.h> | |
22 | #include <stdlib.h> | |
23 | #include <string.h> | |
e054f494 | 24 | #include <stdint.h> |
76a50749 UD |
25 | #include "pthreadP.h" |
26 | #include <hp-timing.h> | |
27 | #include <ldsodefs.h> | |
3e4fc359 | 28 | #include <atomic.h> |
12d7ca07 | 29 | #include <libc-internal.h> |
0e9d6240 | 30 | #include <resolv.h> |
f8de5057 | 31 | #include <kernel-features.h> |
e0db6517 | 32 | #include <exit-thread.h> |
f214ff74 | 33 | #include <default-sched.h> |
a2f0363f | 34 | #include <futex-internal.h> |
ebff9c5c | 35 | #include <tls-setup.h> |
d2e04918 | 36 | #include "libioP.h" |
76a50749 UD |
37 | |
38 | #include <shlib-compat.h> | |
39 | ||
3a097cc7 RM |
40 | #include <stap-probe.h> |
41 | ||
76a50749 | 42 | |
76a50749 UD |
43 | /* Nozero if debugging mode is enabled. */ |
44 | int __pthread_debug; | |
45 | ||
46 | /* Globally enabled events. */ | |
e965d514 | 47 | static td_thr_events_t __nptl_threads_events __attribute_used__; |
76a50749 UD |
48 | |
49 | /* Pointer to descriptor with the last event. */ | |
e965d514 | 50 | static struct pthread *__nptl_last_event __attribute_used__; |
76a50749 | 51 | |
47202270 UD |
52 | /* Number of threads running. */ |
53 | unsigned int __nptl_nthreads = 1; | |
54 | ||
76a50749 UD |
55 | |
56 | /* Code to allocate and deallocate a stack. */ | |
76a50749 UD |
57 | #include "allocatestack.c" |
58 | ||
f8bf15fe CD |
59 | /* CONCURRENCY NOTES: |
60 | ||
61 | Understanding who is the owner of the 'struct pthread' or 'PD' | |
62 | (refers to the value of the 'struct pthread *pd' function argument) | |
63 | is critically important in determining exactly which operations are | |
64 | allowed and which are not and when, particularly when it comes to the | |
65 | implementation of pthread_create, pthread_join, pthread_detach, and | |
66 | other functions which all operate on PD. | |
67 | ||
68 | The owner of PD is responsible for freeing the final resources | |
69 | associated with PD, and may examine the memory underlying PD at any | |
70 | point in time until it frees it back to the OS or to reuse by the | |
71 | runtime. | |
72 | ||
73 | The thread which calls pthread_create is called the creating thread. | |
74 | The creating thread begins as the owner of PD. | |
75 | ||
76 | During startup the new thread may examine PD in coordination with the | |
77 | owner thread (which may be itself). | |
78 | ||
79 | The four cases of ownership transfer are: | |
80 | ||
81 | (1) Ownership of PD is released to the process (all threads may use it) | |
82 | after the new thread starts in a joinable state | |
83 | i.e. pthread_create returns a usable pthread_t. | |
84 | ||
85 | (2) Ownership of PD is released to the new thread starting in a detached | |
86 | state. | |
87 | ||
88 | (3) Ownership of PD is dynamically released to a running thread via | |
89 | pthread_detach. | |
90 | ||
91 | (4) Ownership of PD is acquired by the thread which calls pthread_join. | |
92 | ||
93 | Implementation notes: | |
94 | ||
95 | The PD->stopped_start and thread_ran variables are used to determine | |
96 | exactly which of the four ownership states we are in and therefore | |
97 | what actions can be taken. For example after (2) we cannot read or | |
98 | write from PD anymore since the thread may no longer exist and the | |
fa17b9c7 CD |
99 | memory may be unmapped. |
100 | ||
101 | It is important to point out that PD->lock is being used both | |
102 | similar to a one-shot semaphore and subsequently as a mutex. The | |
103 | lock is taken in the parent to force the child to wait, and then the | |
104 | child releases the lock. However, this semaphore-like effect is used | |
105 | only for synchronizing the parent and child. After startup the lock | |
106 | is used like a mutex to create a critical section during which a | |
107 | single owner modifies the thread parameters. | |
108 | ||
109 | The most complicated cases happen during thread startup: | |
f8bf15fe CD |
110 | |
111 | (a) If the created thread is in a detached (PTHREAD_CREATE_DETACHED), | |
112 | or joinable (default PTHREAD_CREATE_JOINABLE) state and | |
113 | STOPPED_START is true, then the creating thread has ownership of | |
114 | PD until the PD->lock is released by pthread_create. If any | |
115 | errors occur we are in states (c), (d), or (e) below. | |
116 | ||
117 | (b) If the created thread is in a detached state | |
118 | (PTHREAD_CREATED_DETACHED), and STOPPED_START is false, then the | |
119 | creating thread has ownership of PD until it invokes the OS | |
120 | kernel's thread creation routine. If this routine returns | |
121 | without error, then the created thread owns PD; otherwise, see | |
122 | (c) and (e) below. | |
123 | ||
124 | (c) If the detached thread setup failed and THREAD_RAN is true, then | |
125 | the creating thread releases ownership to the new thread by | |
126 | sending a cancellation signal. All threads set THREAD_RAN to | |
127 | true as quickly as possible after returning from the OS kernel's | |
128 | thread creation routine. | |
129 | ||
130 | (d) If the joinable thread setup failed and THREAD_RAN is true, then | |
131 | then the creating thread retains ownership of PD and must cleanup | |
132 | state. Ownership cannot be released to the process via the | |
133 | return of pthread_create since a non-zero result entails PD is | |
134 | undefined and therefore cannot be joined to free the resources. | |
135 | We privately call pthread_join on the thread to finish handling | |
136 | the resource shutdown (Or at least we should, see bug 19511). | |
137 | ||
138 | (e) If the thread creation failed and THREAD_RAN is false, then the | |
139 | creating thread retains ownership of PD and must cleanup state. | |
140 | No waiting for the new thread is required because it never | |
141 | started. | |
142 | ||
143 | The nptl_db interface: | |
144 | ||
145 | The interface with nptl_db requires that we enqueue PD into a linked | |
146 | list and then call a function which the debugger will trap. The PD | |
147 | will then be dequeued and control returned to the thread. The caller | |
148 | at the time must have ownership of PD and such ownership remains | |
149 | after control returns to thread. The enqueued PD is removed from the | |
150 | linked list by the nptl_db callback td_thr_event_getmsg. The debugger | |
151 | must ensure that the thread does not resume execution, otherwise | |
152 | ownership of PD may be lost and examining PD will not be possible. | |
153 | ||
154 | Note that the GNU Debugger as of (December 10th 2015) commit | |
155 | c2c2a31fdb228d41ce3db62b268efea04bd39c18 no longer uses | |
156 | td_thr_event_getmsg and several other related nptl_db interfaces. The | |
157 | principal reason for this is that nptl_db does not support non-stop | |
158 | mode where other threads can run concurrently and modify runtime | |
159 | structures currently in use by the debugger and the nptl_db | |
160 | interface. | |
161 | ||
162 | Axioms: | |
163 | ||
164 | * The create_thread function can never set stopped_start to false. | |
165 | * The created thread can read stopped_start but never write to it. | |
166 | * The variable thread_ran is set some time after the OS thread | |
167 | creation routine returns, how much time after the thread is created | |
168 | is unspecified, but it should be as quickly as possible. | |
169 | ||
170 | */ | |
171 | ||
172 | /* CREATE THREAD NOTES: | |
173 | ||
174 | createthread.c defines the create_thread function, and two macros: | |
32fed10f RM |
175 | START_THREAD_DEFN and START_THREAD_SELF (see below). |
176 | ||
f8bf15fe CD |
177 | create_thread must initialize PD->stopped_start. It should be true |
178 | if the STOPPED_START parameter is true, or if create_thread needs the | |
179 | new thread to synchronize at startup for some other implementation | |
180 | reason. If STOPPED_START will be true, then create_thread is obliged | |
181 | to lock PD->lock before starting the thread. Then pthread_create | |
182 | unlocks PD->lock which synchronizes-with START_THREAD_DEFN in the | |
183 | child thread which does an acquire/release of PD->lock as the last | |
184 | action before calling the user entry point. The goal of all of this | |
185 | is to ensure that the required initial thread attributes are applied | |
186 | (by the creating thread) before the new thread runs user code. Note | |
187 | that the the functions pthread_getschedparam, pthread_setschedparam, | |
188 | pthread_setschedprio, __pthread_tpp_change_priority, and | |
189 | __pthread_current_priority reuse the same lock, PD->lock, for a | |
190 | similar purpose e.g. synchronizing the setting of similar thread | |
191 | attributes. These functions are never called before the thread is | |
192 | created, so don't participate in startup syncronization, but given | |
193 | that the lock is present already and in the unlocked state, reusing | |
194 | it saves space. | |
32fed10f RM |
195 | |
196 | The return value is zero for success or an errno code for failure. | |
197 | If the return value is ENOMEM, that will be translated to EAGAIN, | |
198 | so create_thread need not do that. On failure, *THREAD_RAN should | |
199 | be set to true iff the thread actually started up and then got | |
f8bf15fe | 200 | canceled before calling user code (*PD->start_routine). */ |
32fed10f | 201 | static int create_thread (struct pthread *pd, const struct pthread_attr *attr, |
f8bf15fe | 202 | bool *stopped_start, STACK_VARIABLES_PARMS, |
32fed10f RM |
203 | bool *thread_ran); |
204 | ||
8dea90aa | 205 | #include <createthread.c> |
76a50749 UD |
206 | |
207 | ||
76a50749 | 208 | struct pthread * |
9dd346ff | 209 | __find_in_stack_list (struct pthread *pd) |
76a50749 UD |
210 | { |
211 | list_t *entry; | |
212 | struct pthread *result = NULL; | |
213 | ||
e51deae7 | 214 | lll_lock (stack_cache_lock, LLL_PRIVATE); |
76a50749 UD |
215 | |
216 | list_for_each (entry, &stack_used) | |
217 | { | |
218 | struct pthread *curp; | |
219 | ||
d4f64e1a | 220 | curp = list_entry (entry, struct pthread, list); |
76a50749 UD |
221 | if (curp == pd) |
222 | { | |
223 | result = curp; | |
224 | break; | |
225 | } | |
226 | } | |
227 | ||
228 | if (result == NULL) | |
229 | list_for_each (entry, &__stack_user) | |
230 | { | |
231 | struct pthread *curp; | |
232 | ||
d4f64e1a | 233 | curp = list_entry (entry, struct pthread, list); |
76a50749 UD |
234 | if (curp == pd) |
235 | { | |
236 | result = curp; | |
237 | break; | |
238 | } | |
239 | } | |
240 | ||
e51deae7 | 241 | lll_unlock (stack_cache_lock, LLL_PRIVATE); |
76a50749 UD |
242 | |
243 | return result; | |
244 | } | |
245 | ||
246 | ||
247 | /* Deallocate POSIX thread-local-storage. */ | |
3fa21fd8 UD |
248 | void |
249 | attribute_hidden | |
250 | __nptl_deallocate_tsd (void) | |
76a50749 | 251 | { |
877e51b2 UD |
252 | struct pthread *self = THREAD_SELF; |
253 | ||
76a50749 UD |
254 | /* Maybe no data was ever allocated. This happens often so we have |
255 | a flag for this. */ | |
877e51b2 | 256 | if (THREAD_GETMEM (self, specific_used)) |
76a50749 UD |
257 | { |
258 | size_t round; | |
6b4686a5 | 259 | size_t cnt; |
76a50749 | 260 | |
6b4686a5 UD |
261 | round = 0; |
262 | do | |
76a50749 | 263 | { |
76a50749 UD |
264 | size_t idx; |
265 | ||
c5acd3d7 | 266 | /* So far no new nonzero data entry. */ |
877e51b2 | 267 | THREAD_SETMEM (self, specific_used, false); |
c5acd3d7 | 268 | |
76a50749 | 269 | for (cnt = idx = 0; cnt < PTHREAD_KEY_1STLEVEL_SIZE; ++cnt) |
6b4686a5 UD |
270 | { |
271 | struct pthread_key_data *level2; | |
272 | ||
877e51b2 | 273 | level2 = THREAD_GETMEM_NC (self, specific, cnt); |
6b4686a5 UD |
274 | |
275 | if (level2 != NULL) | |
276 | { | |
277 | size_t inner; | |
278 | ||
279 | for (inner = 0; inner < PTHREAD_KEY_2NDLEVEL_SIZE; | |
280 | ++inner, ++idx) | |
281 | { | |
282 | void *data = level2[inner].data; | |
283 | ||
877e51b2 UD |
284 | if (data != NULL) |
285 | { | |
286 | /* Always clear the data. */ | |
287 | level2[inner].data = NULL; | |
288 | ||
6b4686a5 UD |
289 | /* Make sure the data corresponds to a valid |
290 | key. This test fails if the key was | |
291 | deallocated and also if it was | |
292 | re-allocated. It is the user's | |
293 | responsibility to free the memory in this | |
294 | case. */ | |
877e51b2 UD |
295 | if (level2[inner].seq |
296 | == __pthread_keys[idx].seq | |
297 | /* It is not necessary to register a destructor | |
298 | function. */ | |
299 | && __pthread_keys[idx].destr != NULL) | |
300 | /* Call the user-provided destructor. */ | |
301 | __pthread_keys[idx].destr (data); | |
6b4686a5 UD |
302 | } |
303 | } | |
304 | } | |
305 | else | |
306 | idx += PTHREAD_KEY_1STLEVEL_SIZE; | |
307 | } | |
877e51b2 UD |
308 | |
309 | if (THREAD_GETMEM (self, specific_used) == 0) | |
310 | /* No data has been modified. */ | |
311 | goto just_free; | |
76a50749 | 312 | } |
877e51b2 UD |
313 | /* We only repeat the process a fixed number of times. */ |
314 | while (__builtin_expect (++round < PTHREAD_DESTRUCTOR_ITERATIONS, 0)); | |
76a50749 | 315 | |
877e51b2 UD |
316 | /* Just clear the memory of the first block for reuse. */ |
317 | memset (&THREAD_SELF->specific_1stblock, '\0', | |
318 | sizeof (self->specific_1stblock)); | |
6b4686a5 | 319 | |
877e51b2 | 320 | just_free: |
6b4686a5 UD |
321 | /* Free the memory for the other blocks. */ |
322 | for (cnt = 1; cnt < PTHREAD_KEY_1STLEVEL_SIZE; ++cnt) | |
323 | { | |
324 | struct pthread_key_data *level2; | |
325 | ||
877e51b2 | 326 | level2 = THREAD_GETMEM_NC (self, specific, cnt); |
6b4686a5 UD |
327 | if (level2 != NULL) |
328 | { | |
329 | /* The first block is allocated as part of the thread | |
330 | descriptor. */ | |
331 | free (level2); | |
877e51b2 | 332 | THREAD_SETMEM_NC (self, specific, cnt, NULL); |
6b4686a5 UD |
333 | } |
334 | } | |
335 | ||
877e51b2 | 336 | THREAD_SETMEM (self, specific_used, false); |
76a50749 UD |
337 | } |
338 | } | |
339 | ||
340 | ||
341 | /* Deallocate a thread's stack after optionally making sure the thread | |
342 | descriptor is still valid. */ | |
343 | void | |
344 | __free_tcb (struct pthread *pd) | |
345 | { | |
346 | /* The thread is exiting now. */ | |
ba25bb0f UD |
347 | if (__builtin_expect (atomic_bit_test_set (&pd->cancelhandling, |
348 | TERMINATED_BIT) == 0, 1)) | |
76a50749 UD |
349 | { |
350 | /* Remove the descriptor from the list. */ | |
351 | if (DEBUGGING_P && __find_in_stack_list (pd) == NULL) | |
352 | /* Something is really wrong. The descriptor for a still | |
353 | running thread is gone. */ | |
354 | abort (); | |
355 | ||
f17efcb4 | 356 | /* Free TPP data. */ |
a1ffb40e | 357 | if (__glibc_unlikely (pd->tpp != NULL)) |
f17efcb4 UD |
358 | { |
359 | struct priority_protection_data *tpp = pd->tpp; | |
360 | ||
361 | pd->tpp = NULL; | |
362 | free (tpp); | |
363 | } | |
364 | ||
76a50749 UD |
365 | /* Queue the stack memory block for reuse and exit the process. The |
366 | kernel will signal via writing to the address returned by | |
367 | QUEUE-STACK when the stack is available. */ | |
368 | __deallocate_stack (pd); | |
369 | } | |
370 | } | |
371 | ||
372 | ||
32fed10f RM |
373 | /* Local function to start thread and handle cleanup. |
374 | createthread.c defines the macro START_THREAD_DEFN to the | |
375 | declaration that its create_thread function will refer to, and | |
376 | START_THREAD_SELF to the expression to optimally deliver the new | |
377 | thread's THREAD_SELF value. */ | |
378 | START_THREAD_DEFN | |
76a50749 | 379 | { |
32fed10f | 380 | struct pthread *pd = START_THREAD_SELF; |
76a50749 | 381 | |
0e9d6240 UD |
382 | /* Initialize resolver state pointer. */ |
383 | __resp = &pd->res; | |
384 | ||
fd5bdc09 UD |
385 | /* Initialize pointers to locale data. */ |
386 | __ctype_init (); | |
387 | ||
66f1b8ee | 388 | /* Allow setxid from now onwards. */ |
a1ffb40e | 389 | if (__glibc_unlikely (atomic_exchange_acq (&pd->setxid_futex, 0) == -2)) |
a2f0363f | 390 | futex_wake (&pd->setxid_futex, 1, FUTEX_PRIVATE); |
66f1b8ee | 391 | |
0f6699ea UD |
392 | #ifdef __NR_set_robust_list |
393 | # ifndef __ASSUME_SET_ROBUST_LIST | |
394 | if (__set_robust_list_avail >= 0) | |
395 | # endif | |
396 | { | |
397 | INTERNAL_SYSCALL_DECL (err); | |
398 | /* This call should never fail because the initial call in init.c | |
399 | succeeded. */ | |
400 | INTERNAL_SYSCALL (set_robust_list, err, 2, &pd->robust_head, | |
401 | sizeof (struct robust_list_head)); | |
402 | } | |
403 | #endif | |
404 | ||
b051fc44 UD |
405 | /* If the parent was running cancellation handlers while creating |
406 | the thread the new thread inherited the signal mask. Reset the | |
407 | cancellation signal mask. */ | |
a1ffb40e | 408 | if (__glibc_unlikely (pd->parent_cancelhandling & CANCELING_BITMASK)) |
b051fc44 UD |
409 | { |
410 | INTERNAL_SYSCALL_DECL (err); | |
411 | sigset_t mask; | |
412 | __sigemptyset (&mask); | |
413 | __sigaddset (&mask, SIGCANCEL); | |
414 | (void) INTERNAL_SYSCALL (rt_sigprocmask, err, 4, SIG_UNBLOCK, &mask, | |
415 | NULL, _NSIG / 8); | |
416 | } | |
417 | ||
76a50749 UD |
418 | /* This is where the try/finally block should be created. For |
419 | compilers without that support we do use setjmp. */ | |
877e51b2 UD |
420 | struct pthread_unwind_buf unwind_buf; |
421 | ||
d6cc1829 L |
422 | int not_first_call; |
423 | not_first_call = setjmp ((struct __jmp_buf_tag *) unwind_buf.cancel_jmp_buf); | |
424 | ||
425 | /* No previous handlers. NB: This must be done after setjmp since the | |
426 | private space in the unwind jump buffer may overlap space used by | |
427 | setjmp to store extra architecture-specific information which is | |
428 | never used by the cancellation-specific __libc_unwind_longjmp. | |
429 | ||
430 | The private space is allowed to overlap because the unwinder never | |
431 | has to return through any of the jumped-to call frames, and thus | |
432 | only a minimum amount of saved data need be stored, and for example, | |
433 | need not include the process signal mask information. This is all | |
434 | an optimization to reduce stack usage when pushing cancellation | |
435 | handlers. */ | |
877e51b2 UD |
436 | unwind_buf.priv.data.prev = NULL; |
437 | unwind_buf.priv.data.cleanup = NULL; | |
438 | ||
a1ffb40e | 439 | if (__glibc_likely (! not_first_call)) |
76a50749 | 440 | { |
877e51b2 UD |
441 | /* Store the new cleanup handler info. */ |
442 | THREAD_SETMEM (pd, cleanup_jmp_buf, &unwind_buf); | |
443 | ||
f8bf15fe CD |
444 | /* We are either in (a) or (b), and in either case we either own |
445 | PD already (2) or are about to own PD (1), and so our only | |
446 | restriction would be that we can't free PD until we know we | |
447 | have ownership (see CONCURRENCY NOTES above). */ | |
a1ffb40e | 448 | if (__glibc_unlikely (pd->stopped_start)) |
5f66b766 UD |
449 | { |
450 | int oldtype = CANCEL_ASYNC (); | |
362038b0 | 451 | |
5f66b766 | 452 | /* Get the lock the parent locked to force synchronization. */ |
e51deae7 | 453 | lll_lock (pd->lock, LLL_PRIVATE); |
f8bf15fe CD |
454 | |
455 | /* We have ownership of PD now. */ | |
456 | ||
5f66b766 | 457 | /* And give it up right away. */ |
e51deae7 | 458 | lll_unlock (pd->lock, LLL_PRIVATE); |
362038b0 | 459 | |
5f66b766 UD |
460 | CANCEL_RESET (oldtype); |
461 | } | |
362038b0 | 462 | |
3a097cc7 RM |
463 | LIBC_PROBE (pthread_start, 3, (pthread_t) pd, pd->start_routine, pd->arg); |
464 | ||
76a50749 | 465 | /* Run the code the user provided. */ |
ce7528f6 AZ |
466 | void *ret; |
467 | if (pd->c11) | |
468 | { | |
469 | /* The function pointer of the c11 thread start is cast to an incorrect | |
470 | type on __pthread_create_2_1 call, however it is casted back to correct | |
471 | one so the call behavior is well-defined (it is assumed that pointers | |
472 | to void are able to represent all values of int. */ | |
473 | int (*start)(void*) = (int (*) (void*)) pd->start_routine; | |
474 | ret = (void*) (uintptr_t) start (pd->arg); | |
475 | } | |
476 | else | |
477 | ret = pd->start_routine (pd->arg); | |
478 | THREAD_SETMEM (pd, result, ret); | |
76a50749 UD |
479 | } |
480 | ||
ba384f6e | 481 | /* Call destructors for the thread_local TLS variables. */ |
e57b0c61 RM |
482 | #ifndef SHARED |
483 | if (&__call_tls_dtors != NULL) | |
484 | #endif | |
485 | __call_tls_dtors (); | |
ba384f6e | 486 | |
6b4686a5 | 487 | /* Run the destructor for the thread-local data. */ |
3fa21fd8 | 488 | __nptl_deallocate_tsd (); |
6b4686a5 | 489 | |
12d7ca07 RM |
490 | /* Clean up any state libc stored in thread-local variables. */ |
491 | __libc_thread_freeres (); | |
76a50749 | 492 | |
47202270 UD |
493 | /* If this is the last thread we terminate the process now. We |
494 | do not notify the debugger, it might just irritate it if there | |
495 | is no thread left. */ | |
a1ffb40e | 496 | if (__glibc_unlikely (atomic_decrement_and_test (&__nptl_nthreads))) |
47202270 UD |
497 | /* This was the last thread. */ |
498 | exit (0); | |
499 | ||
76a50749 | 500 | /* Report the death of the thread if this is wanted. */ |
a1ffb40e | 501 | if (__glibc_unlikely (pd->report_events)) |
76a50749 UD |
502 | { |
503 | /* See whether TD_DEATH is in any of the mask. */ | |
504 | const int idx = __td_eventword (TD_DEATH); | |
505 | const uint32_t mask = __td_eventmask (TD_DEATH); | |
506 | ||
507 | if ((mask & (__nptl_threads_events.event_bits[idx] | |
508 | | pd->eventbuf.eventmask.event_bits[idx])) != 0) | |
509 | { | |
510 | /* Yep, we have to signal the death. Add the descriptor to | |
511 | the list but only if it is not already on it. */ | |
512 | if (pd->nextevent == NULL) | |
513 | { | |
514 | pd->eventbuf.eventnum = TD_DEATH; | |
515 | pd->eventbuf.eventdata = pd; | |
516 | ||
517 | do | |
518 | pd->nextevent = __nptl_last_event; | |
5a3ab2fc UD |
519 | while (atomic_compare_and_exchange_bool_acq (&__nptl_last_event, |
520 | pd, pd->nextevent)); | |
76a50749 UD |
521 | } |
522 | ||
f8bf15fe CD |
523 | /* Now call the function which signals the event. See |
524 | CONCURRENCY NOTES for the nptl_db interface comments. */ | |
76a50749 UD |
525 | __nptl_death_event (); |
526 | } | |
527 | } | |
528 | ||
6461e577 RM |
529 | /* The thread is exiting now. Don't set this bit until after we've hit |
530 | the event-reporting breakpoint, so that td_thr_get_info on us while at | |
531 | the breakpoint reports TD_THR_RUN state rather than TD_THR_ZOMBIE. */ | |
532 | atomic_bit_set (&pd->cancelhandling, EXITING_BIT); | |
76a50749 | 533 | |
0f6699ea | 534 | #ifndef __ASSUME_SET_ROBUST_LIST |
1bcfb5a5 | 535 | /* If this thread has any robust mutexes locked, handle them now. */ |
06be6368 | 536 | # if __PTHREAD_MUTEX_HAVE_PREV |
0f6699ea UD |
537 | void *robust = pd->robust_head.list; |
538 | # else | |
b007ce7c | 539 | __pthread_slist_t *robust = pd->robust_list.__next; |
0f6699ea | 540 | # endif |
df47504c UD |
541 | /* We let the kernel do the notification if it is able to do so. |
542 | If we have to do it here there for sure are no PI mutexes involved | |
543 | since the kernel support for them is even more recent. */ | |
0f6699ea | 544 | if (__set_robust_list_avail < 0 |
df47504c | 545 | && __builtin_expect (robust != (void *) &pd->robust_head, 0)) |
1bcfb5a5 UD |
546 | { |
547 | do | |
548 | { | |
b007ce7c | 549 | struct __pthread_mutex_s *this = (struct __pthread_mutex_s *) |
0f6699ea UD |
550 | ((char *) robust - offsetof (struct __pthread_mutex_s, |
551 | __list.__next)); | |
552 | robust = *((void **) robust); | |
d804f5df | 553 | |
06be6368 | 554 | # if __PTHREAD_MUTEX_HAVE_PREV |
b007ce7c | 555 | this->__list.__prev = NULL; |
0f6699ea UD |
556 | # endif |
557 | this->__list.__next = NULL; | |
1bcfb5a5 | 558 | |
c0c6bac9 | 559 | atomic_or (&this->__lock, FUTEX_OWNER_DIED); |
a2f0363f TR |
560 | futex_wake ((unsigned int *) &this->__lock, 1, |
561 | /* XYZ */ FUTEX_SHARED); | |
1bcfb5a5 | 562 | } |
df47504c | 563 | while (robust != (void *) &pd->robust_head); |
1bcfb5a5 | 564 | } |
0f6699ea | 565 | #endif |
1bcfb5a5 | 566 | |
01b87c65 AZ |
567 | advise_stack_range (pd->stackblock, pd->stackblock_size, (uintptr_t) pd, |
568 | pd->guardsize); | |
b42a214c | 569 | |
76a50749 UD |
570 | /* If the thread is detached free the TCB. */ |
571 | if (IS_DETACHED (pd)) | |
572 | /* Free the TCB. */ | |
573 | __free_tcb (pd); | |
a1ffb40e | 574 | else if (__glibc_unlikely (pd->cancelhandling & SETXID_BITMASK)) |
dff9a7a1 UD |
575 | { |
576 | /* Some other thread might call any of the setXid functions and expect | |
577 | us to reply. In this case wait until we did that. */ | |
578 | do | |
a2f0363f TR |
579 | /* XXX This differs from the typical futex_wait_simple pattern in that |
580 | the futex_wait condition (setxid_futex) is different from the | |
581 | condition used in the surrounding loop (cancelhandling). We need | |
582 | to check and document why this is correct. */ | |
583 | futex_wait_simple (&pd->setxid_futex, 0, FUTEX_PRIVATE); | |
dff9a7a1 UD |
584 | while (pd->cancelhandling & SETXID_BITMASK); |
585 | ||
586 | /* Reset the value so that the stack can be reused. */ | |
587 | pd->setxid_futex = 0; | |
588 | } | |
76a50749 UD |
589 | |
590 | /* We cannot call '_exit' here. '_exit' will terminate the process. | |
591 | ||
592 | The 'exit' implementation in the kernel will signal when the | |
adcdc775 | 593 | process is really dead since 'clone' got passed the CLONE_CHILD_CLEARTID |
76a50749 UD |
594 | flag. The 'tid' field in the TCB will be set to zero. |
595 | ||
596 | The exit code is zero since in case all threads exit by calling | |
597 | 'pthread_exit' the exit status must be 0 (zero). */ | |
e0db6517 | 598 | __exit_thread (); |
76a50749 UD |
599 | |
600 | /* NOTREACHED */ | |
32fed10f RM |
601 | } |
602 | ||
603 | ||
604 | /* Return true iff obliged to report TD_CREATE events. */ | |
605 | static bool | |
606 | report_thread_creation (struct pthread *pd) | |
607 | { | |
608 | if (__glibc_unlikely (THREAD_GETMEM (THREAD_SELF, report_events))) | |
609 | { | |
610 | /* The parent thread is supposed to report events. | |
611 | Check whether the TD_CREATE event is needed, too. */ | |
612 | const size_t idx = __td_eventword (TD_CREATE); | |
613 | const uint32_t mask = __td_eventmask (TD_CREATE); | |
614 | ||
615 | return ((mask & (__nptl_threads_events.event_bits[idx] | |
616 | | pd->eventbuf.eventmask.event_bits[idx])) != 0); | |
617 | } | |
618 | return false; | |
76a50749 UD |
619 | } |
620 | ||
621 | ||
76a50749 | 622 | int |
80d9be81 JM |
623 | __pthread_create_2_1 (pthread_t *newthread, const pthread_attr_t *attr, |
624 | void *(*start_routine) (void *), void *arg) | |
76a50749 UD |
625 | { |
626 | STACK_VARIABLES; | |
76a50749 | 627 | |
1e6da2b0 | 628 | const struct pthread_attr *iattr = (struct pthread_attr *) attr; |
61dd6208 SP |
629 | struct pthread_attr default_attr; |
630 | bool free_cpuset = false; | |
ce7528f6 AZ |
631 | bool c11 = (attr == ATTR_C11_THREAD); |
632 | if (iattr == NULL || c11) | |
61dd6208 SP |
633 | { |
634 | lll_lock (__default_pthread_attr_lock, LLL_PRIVATE); | |
635 | default_attr = __default_pthread_attr; | |
636 | size_t cpusetsize = default_attr.cpusetsize; | |
637 | if (cpusetsize > 0) | |
638 | { | |
639 | cpu_set_t *cpuset; | |
640 | if (__glibc_likely (__libc_use_alloca (cpusetsize))) | |
641 | cpuset = __alloca (cpusetsize); | |
642 | else | |
643 | { | |
644 | cpuset = malloc (cpusetsize); | |
645 | if (cpuset == NULL) | |
646 | { | |
647 | lll_unlock (__default_pthread_attr_lock, LLL_PRIVATE); | |
648 | return ENOMEM; | |
649 | } | |
650 | free_cpuset = true; | |
651 | } | |
652 | memcpy (cpuset, default_attr.cpuset, cpusetsize); | |
653 | default_attr.cpuset = cpuset; | |
654 | } | |
655 | lll_unlock (__default_pthread_attr_lock, LLL_PRIVATE); | |
656 | iattr = &default_attr; | |
657 | } | |
76a50749 | 658 | |
dff9a7a1 | 659 | struct pthread *pd = NULL; |
1e6da2b0 | 660 | int err = ALLOCATE_STACK (iattr, &pd); |
61dd6208 SP |
661 | int retval = 0; |
662 | ||
a1ffb40e | 663 | if (__glibc_unlikely (err != 0)) |
76a50749 | 664 | /* Something went wrong. Maybe a parameter of the attributes is |
e988dba9 JL |
665 | invalid or we could not allocate memory. Note we have to |
666 | translate error codes. */ | |
61dd6208 SP |
667 | { |
668 | retval = err == ENOMEM ? EAGAIN : err; | |
669 | goto out; | |
670 | } | |
76a50749 UD |
671 | |
672 | ||
673 | /* Initialize the TCB. All initializations with zero should be | |
674 | performed in 'get_cached_stack'. This way we avoid doing this if | |
675 | the stack freshly allocated with 'mmap'. */ | |
676 | ||
d7329d4b | 677 | #if TLS_TCB_AT_TP |
76a50749 | 678 | /* Reference to the TCB itself. */ |
55c11fbd | 679 | pd->header.self = pd; |
76a50749 | 680 | |
d4f64e1a | 681 | /* Self-reference for TLS. */ |
55c11fbd | 682 | pd->header.tcb = pd; |
76a50749 UD |
683 | #endif |
684 | ||
685 | /* Store the address of the start routine and the parameter. Since | |
686 | we do not start the function directly the stillborn thread will | |
687 | get the information from its thread descriptor. */ | |
688 | pd->start_routine = start_routine; | |
689 | pd->arg = arg; | |
ce7528f6 | 690 | pd->c11 = c11; |
76a50749 UD |
691 | |
692 | /* Copy the thread attribute flags. */ | |
14ffbc83 UD |
693 | struct pthread *self = THREAD_SELF; |
694 | pd->flags = ((iattr->flags & ~(ATTR_FLAG_SCHED_SET | ATTR_FLAG_POLICY_SET)) | |
695 | | (self->flags & (ATTR_FLAG_SCHED_SET | ATTR_FLAG_POLICY_SET))); | |
76a50749 UD |
696 | |
697 | /* Initialize the field for the ID of the thread which is waiting | |
698 | for us. This is a self-reference in case the thread is created | |
699 | detached. */ | |
700 | pd->joinid = iattr->flags & ATTR_FLAG_DETACHSTATE ? pd : NULL; | |
701 | ||
702 | /* The debug events are inherited from the parent. */ | |
14ffbc83 UD |
703 | pd->eventbuf = self->eventbuf; |
704 | ||
76a50749 | 705 | |
14ffbc83 UD |
706 | /* Copy the parent's scheduling parameters. The flags will say what |
707 | is valid and what is not. */ | |
708 | pd->schedpolicy = self->schedpolicy; | |
709 | pd->schedparam = self->schedparam; | |
76a50749 | 710 | |
35f1e827 UD |
711 | /* Copy the stack guard canary. */ |
712 | #ifdef THREAD_COPY_STACK_GUARD | |
713 | THREAD_COPY_STACK_GUARD (pd); | |
714 | #endif | |
715 | ||
827b7087 UD |
716 | /* Copy the pointer guard value. */ |
717 | #ifdef THREAD_COPY_POINTER_GUARD | |
718 | THREAD_COPY_POINTER_GUARD (pd); | |
719 | #endif | |
720 | ||
ebff9c5c L |
721 | /* Setup tcbhead. */ |
722 | tls_setup_tcbhead (pd); | |
723 | ||
32fed10f RM |
724 | /* Verify the sysinfo bits were copied in allocate_stack if needed. */ |
725 | #ifdef NEED_DL_SYSINFO | |
726 | CHECK_THREAD_SYSINFO (pd); | |
727 | #endif | |
728 | ||
729 | /* Inform start_thread (above) about cancellation state that might | |
730 | translate into inherited signal state. */ | |
731 | pd->parent_cancelhandling = THREAD_GETMEM (THREAD_SELF, cancelhandling); | |
732 | ||
14ffbc83 | 733 | /* Determine scheduling parameters for the thread. */ |
61dd6208 | 734 | if (__builtin_expect ((iattr->flags & ATTR_FLAG_NOTINHERITSCHED) != 0, 0) |
14ffbc83 | 735 | && (iattr->flags & (ATTR_FLAG_SCHED_SET | ATTR_FLAG_POLICY_SET)) != 0) |
76a50749 | 736 | { |
14ffbc83 UD |
737 | /* Use the scheduling parameters the user provided. */ |
738 | if (iattr->flags & ATTR_FLAG_POLICY_SET) | |
33cd1f74 RM |
739 | { |
740 | pd->schedpolicy = iattr->schedpolicy; | |
741 | pd->flags |= ATTR_FLAG_POLICY_SET; | |
742 | } | |
14ffbc83 | 743 | if (iattr->flags & ATTR_FLAG_SCHED_SET) |
33cd1f74 RM |
744 | { |
745 | /* The values were validated in pthread_attr_setschedparam. */ | |
746 | pd->schedparam = iattr->schedparam; | |
747 | pd->flags |= ATTR_FLAG_SCHED_SET; | |
748 | } | |
f214ff74 RM |
749 | |
750 | if ((pd->flags & (ATTR_FLAG_SCHED_SET | ATTR_FLAG_POLICY_SET)) | |
751 | != (ATTR_FLAG_SCHED_SET | ATTR_FLAG_POLICY_SET)) | |
752 | collect_default_sched (pd); | |
76a50749 UD |
753 | } |
754 | ||
d2e04918 SN |
755 | if (__glibc_unlikely (__nptl_nthreads == 1)) |
756 | _IO_enable_locks (); | |
757 | ||
76a50749 UD |
758 | /* Pass the descriptor to the caller. */ |
759 | *newthread = (pthread_t) pd; | |
760 | ||
5acf7263 RM |
761 | LIBC_PROBE (pthread_create, 4, newthread, attr, start_routine, arg); |
762 | ||
32fed10f RM |
763 | /* One more thread. We cannot have the thread do this itself, since it |
764 | might exist but not have been scheduled yet by the time we've returned | |
765 | and need to check the value to behave correctly. We must do it before | |
766 | creating the thread, in case it does get scheduled first and then | |
767 | might mistakenly think it was the only thread. In the failure case, | |
768 | we momentarily store a false value; this doesn't matter because there | |
769 | is no kosher thing a signal handler interrupting us right here can do | |
770 | that cares whether the thread count is correct. */ | |
771 | atomic_increment (&__nptl_nthreads); | |
772 | ||
f8bf15fe CD |
773 | /* Our local value of stopped_start and thread_ran can be accessed at |
774 | any time. The PD->stopped_start may only be accessed if we have | |
775 | ownership of PD (see CONCURRENCY NOTES above). */ | |
776 | bool stopped_start = false; bool thread_ran = false; | |
32fed10f | 777 | |
76a50749 | 778 | /* Start the thread. */ |
32fed10f RM |
779 | if (__glibc_unlikely (report_thread_creation (pd))) |
780 | { | |
f8bf15fe CD |
781 | stopped_start = true; |
782 | ||
783 | /* We always create the thread stopped at startup so we can | |
784 | notify the debugger. */ | |
785 | retval = create_thread (pd, iattr, &stopped_start, | |
786 | STACK_VARIABLES_ARGS, &thread_ran); | |
32fed10f RM |
787 | if (retval == 0) |
788 | { | |
f8bf15fe CD |
789 | /* We retain ownership of PD until (a) (see CONCURRENCY NOTES |
790 | above). */ | |
791 | ||
792 | /* Assert stopped_start is true in both our local copy and the | |
793 | PD copy. */ | |
794 | assert (stopped_start); | |
32fed10f RM |
795 | assert (pd->stopped_start); |
796 | ||
797 | /* Now fill in the information about the new thread in | |
798 | the newly created thread's data structure. We cannot let | |
799 | the new thread do this since we don't know whether it was | |
800 | already scheduled when we send the event. */ | |
801 | pd->eventbuf.eventnum = TD_CREATE; | |
802 | pd->eventbuf.eventdata = pd; | |
803 | ||
804 | /* Enqueue the descriptor. */ | |
805 | do | |
806 | pd->nextevent = __nptl_last_event; | |
807 | while (atomic_compare_and_exchange_bool_acq (&__nptl_last_event, | |
808 | pd, pd->nextevent) | |
809 | != 0); | |
810 | ||
f8bf15fe CD |
811 | /* Now call the function which signals the event. See |
812 | CONCURRENCY NOTES for the nptl_db interface comments. */ | |
32fed10f RM |
813 | __nptl_create_event (); |
814 | } | |
815 | } | |
816 | else | |
f8bf15fe CD |
817 | retval = create_thread (pd, iattr, &stopped_start, |
818 | STACK_VARIABLES_ARGS, &thread_ran); | |
32fed10f RM |
819 | |
820 | if (__glibc_unlikely (retval != 0)) | |
821 | { | |
32fed10f | 822 | if (thread_ran) |
f8bf15fe CD |
823 | /* State (c) or (d) and we may not have PD ownership (see |
824 | CONCURRENCY NOTES above). We can assert that STOPPED_START | |
825 | must have been true because thread creation didn't fail, but | |
826 | thread attribute setting did. */ | |
827 | /* See bug 19511 which explains why doing nothing here is a | |
828 | resource leak for a joinable thread. */ | |
829 | assert (stopped_start); | |
32fed10f RM |
830 | else |
831 | { | |
f8bf15fe CD |
832 | /* State (e) and we have ownership of PD (see CONCURRENCY |
833 | NOTES above). */ | |
834 | ||
32fed10f RM |
835 | /* Oops, we lied for a second. */ |
836 | atomic_decrement (&__nptl_nthreads); | |
837 | ||
838 | /* Perhaps a thread wants to change the IDs and is waiting for this | |
839 | stillborn thread. */ | |
840 | if (__glibc_unlikely (atomic_exchange_acq (&pd->setxid_futex, 0) | |
841 | == -2)) | |
a2f0363f | 842 | futex_wake (&pd->setxid_futex, 1, FUTEX_PRIVATE); |
32fed10f RM |
843 | |
844 | /* Free the resources. */ | |
845 | __deallocate_stack (pd); | |
846 | } | |
847 | ||
848 | /* We have to translate error codes. */ | |
849 | if (retval == ENOMEM) | |
850 | retval = EAGAIN; | |
851 | } | |
852 | else | |
853 | { | |
f8bf15fe CD |
854 | /* We don't know if we have PD ownership. Once we check the local |
855 | stopped_start we'll know if we're in state (a) or (b) (see | |
856 | CONCURRENCY NOTES above). */ | |
857 | if (stopped_start) | |
858 | /* State (a), we own PD. The thread blocked on this lock either | |
859 | because we're doing TD_CREATE event reporting, or for some | |
860 | other reason that create_thread chose. Now let it run | |
861 | free. */ | |
32fed10f RM |
862 | lll_unlock (pd->lock, LLL_PRIVATE); |
863 | ||
864 | /* We now have for sure more than one thread. The main thread might | |
865 | not yet have the flag set. No need to set the global variable | |
866 | again if this is what we use. */ | |
867 | THREAD_SETMEM (THREAD_SELF, header.multiple_threads, 1); | |
868 | } | |
61dd6208 SP |
869 | |
870 | out: | |
871 | if (__glibc_unlikely (free_cpuset)) | |
872 | free (default_attr.cpuset); | |
873 | ||
874 | return retval; | |
76a50749 UD |
875 | } |
876 | versioned_symbol (libpthread, __pthread_create_2_1, pthread_create, GLIBC_2_1); | |
877 | ||
878 | ||
879 | #if SHLIB_COMPAT(libpthread, GLIBC_2_0, GLIBC_2_1) | |
880 | int | |
80d9be81 JM |
881 | __pthread_create_2_0 (pthread_t *newthread, const pthread_attr_t *attr, |
882 | void *(*start_routine) (void *), void *arg) | |
76a50749 UD |
883 | { |
884 | /* The ATTR attribute is not really of type `pthread_attr_t *'. It has | |
885 | the old size and access to the new members might crash the program. | |
886 | We convert the struct now. */ | |
887 | struct pthread_attr new_attr; | |
888 | ||
889 | if (attr != NULL) | |
890 | { | |
891 | struct pthread_attr *iattr = (struct pthread_attr *) attr; | |
892 | size_t ps = __getpagesize (); | |
893 | ||
894 | /* Copy values from the user-provided attributes. */ | |
895 | new_attr.schedparam = iattr->schedparam; | |
896 | new_attr.schedpolicy = iattr->schedpolicy; | |
897 | new_attr.flags = iattr->flags; | |
898 | ||
899 | /* Fill in default values for the fields not present in the old | |
900 | implementation. */ | |
901 | new_attr.guardsize = ps; | |
902 | new_attr.stackaddr = NULL; | |
903 | new_attr.stacksize = 0; | |
ca85ede0 | 904 | new_attr.cpuset = NULL; |
76a50749 UD |
905 | |
906 | /* We will pass this value on to the real implementation. */ | |
907 | attr = (pthread_attr_t *) &new_attr; | |
908 | } | |
909 | ||
910 | return __pthread_create_2_1 (newthread, attr, start_routine, arg); | |
911 | } | |
912 | compat_symbol (libpthread, __pthread_create_2_0, pthread_create, | |
913 | GLIBC_2_0); | |
914 | #endif | |
7f08f55a RM |
915 | \f |
916 | /* Information for libthread_db. */ | |
917 | ||
918 | #include "../nptl_db/db_info.c" | |
b639d0c9 UD |
919 | \f |
920 | /* If pthread_create is present, libgcc_eh.a and libsupc++.a expects some other POSIX thread | |
921 | functions to be present as well. */ | |
fa872e1b AZ |
922 | PTHREAD_STATIC_FN_REQUIRE (__pthread_mutex_lock) |
923 | PTHREAD_STATIC_FN_REQUIRE (__pthread_mutex_trylock) | |
924 | PTHREAD_STATIC_FN_REQUIRE (__pthread_mutex_unlock) | |
b639d0c9 | 925 | |
fa872e1b AZ |
926 | PTHREAD_STATIC_FN_REQUIRE (__pthread_once) |
927 | PTHREAD_STATIC_FN_REQUIRE (__pthread_cancel) | |
b639d0c9 | 928 | |
fa872e1b AZ |
929 | PTHREAD_STATIC_FN_REQUIRE (__pthread_key_create) |
930 | PTHREAD_STATIC_FN_REQUIRE (__pthread_key_delete) | |
931 | PTHREAD_STATIC_FN_REQUIRE (__pthread_setspecific) | |
932 | PTHREAD_STATIC_FN_REQUIRE (__pthread_getspecific) |