1 #define _GNU_SOURCE
2 #define ANON_STACK_NAME_SIZE 50
3 #include "musl_log.h"
4 #include "pthread_impl.h"
5 #include "stdio_impl.h"
6 #include "libc.h"
7 #include "lock.h"
8 #include <sys/mman.h>
9 #include <sys/prctl.h>
10 #include <string.h>
11 #include <stddef.h>
12 #include <stdarg.h>
13
14 pid_t getpid(void);
15
log_print(const char * info,...)16 void log_print(const char* info, ...)
17 {
18 va_list ap;
19 va_start(ap, info);
20 vfprintf(stdout, info, ap);
21 va_end(ap);
22 }
23
stack_naming(struct pthread * new)24 void stack_naming(struct pthread *new) {
25 size_t size_len;
26 unsigned char *start_addr;
27 char name[ANON_STACK_NAME_SIZE];
28 if (new->guard_size) {
29 snprintf(name, ANON_STACK_NAME_SIZE, "guard:%d", new->tid);
30 prctl(PR_SET_VMA, PR_SET_VMA_ANON_NAME, new->map_base, new->guard_size, name);
31 start_addr = new->map_base + new->guard_size;
32 size_len = new->map_size - new->guard_size;
33 memset(name, 0, ANON_STACK_NAME_SIZE);
34 } else {
35 start_addr = new->map_base;
36 size_len = new->map_size;
37 }
38 snprintf(name, ANON_STACK_NAME_SIZE, "stack:%d", new->tid);
39 prctl(PR_SET_VMA, PR_SET_VMA_ANON_NAME, start_addr, size_len, name);
40 };
41
42 #ifdef RESERVE_SIGNAL_STACK
43 #if defined (__LP64__)
44 #define RESERVE_SIGNAL_STACK_SIZE (32 * 1024)
45 #else
46 #define RESERVE_SIGNAL_STACK_SIZE (20 * 1024)
47 #endif
__pthread_reserve_signal_stack()48 void __pthread_reserve_signal_stack()
49 {
50 void* stack = mmap(NULL, RESERVE_SIGNAL_STACK_SIZE, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
51 if (stack != MAP_FAILED) {
52 if (mprotect(stack, __default_guardsize, PROT_NONE) == -1) {
53 munmap(stack, RESERVE_SIGNAL_STACK_SIZE);
54 return;
55 }
56 }
57
58 stack_t signal_stack;
59 signal_stack.ss_sp = (uint8_t*)stack + __default_guardsize;
60 signal_stack.ss_size = RESERVE_SIGNAL_STACK_SIZE - __default_guardsize;
61 signal_stack.ss_flags = 0;
62 sigaltstack(&signal_stack, NULL);
63
64 pthread_t self = __pthread_self();
65 self->signal_stack = stack;
66 char name[ANON_STACK_NAME_SIZE];
67 snprintf(name, ANON_STACK_NAME_SIZE, "signal_stack:%d", __pthread_self()->tid);
68 prctl(PR_SET_VMA, PR_SET_VMA_ANON_NAME, signal_stack.ss_sp, signal_stack.ss_size, name);
69 return;
70 }
71
72 #ifdef ENABLE_HWASAN
73 __attribute__((no_sanitize("hwaddress")))
74 #endif
__pthread_release_signal_stack()75 void __pthread_release_signal_stack()
76 {
77 pthread_t self = __pthread_self();
78 if (self->signal_stack == NULL) {
79 return;
80 }
81
82 stack_t signal_stack, old_stack;
83 memset(&signal_stack, 0, sizeof(signal_stack));
84 signal_stack.ss_flags = SS_DISABLE;
85 sigaltstack(&signal_stack, &old_stack);
86 munmap(self->signal_stack, __default_guardsize);
87 if (old_stack.ss_flags != SS_DISABLE) {
88 munmap(old_stack.ss_sp, old_stack.ss_size);
89 }
90 self->signal_stack = NULL;
91 }
92
93 weak_alias(__pthread_reserve_signal_stack, pthread_reserve_signal_stack);
94 weak_alias(__pthread_release_signal_stack, pthread_release_signal_stack);
95 #endif
96
dummy_0()97 static void dummy_0()
98 {
99 }
100 weak_alias(dummy_0, __acquire_ptc);
101 weak_alias(dummy_0, __release_ptc);
102 weak_alias(dummy_0, __pthread_tsd_run_dtors);
103 weak_alias(dummy_0, __do_orphaned_stdio_locks);
104 weak_alias(dummy_0, __dl_thread_cleanup);
105 weak_alias(dummy_0, __membarrier_init);
106
107 #define TID_ERROR_0 (0)
108 #define TID_ERROR_INIT (-1)
109 #define COUNT_ERROR_INIT (-10000)
110
111 static int tl_lock_count;
112 static int tl_lock_waiters;
113 static int tl_lock_tid_fail = TID_ERROR_INIT;
114 static int tl_lock_count_tid = TID_ERROR_INIT;
115 static int tl_lock_count_tid_sub = TID_ERROR_INIT;
116 static int tl_lock_count_fail = COUNT_ERROR_INIT;
117 static int thread_list_lock_after_lock = TID_ERROR_INIT;
118 static int thread_list_lock_pre_unlock = TID_ERROR_INIT;
119 static int thread_list_lock_pthread_exit = TID_ERROR_INIT;
120 static int thread_list_lock_tid_overlimit = TID_ERROR_INIT;
121 static int register_count = 0;
122 static pid_t g_dlcloseLockStatus = TID_ERROR_0, g_dlcloseLockLastExitTid = TID_ERROR_0;
123
124 struct call_tl_lock tl_lock_caller_count = { 0 };
125
get_tl_lock_count(void)126 int get_tl_lock_count(void)
127 {
128 return tl_lock_count;
129 }
130
get_tl_lock_waiters(void)131 int get_tl_lock_waiters(void)
132 {
133 return tl_lock_waiters;
134 }
135
get_tl_lock_tid_fail(void)136 int get_tl_lock_tid_fail(void)
137 {
138 return tl_lock_tid_fail;
139 }
140
get_tl_lock_count_tid(void)141 int get_tl_lock_count_tid(void)
142 {
143 return tl_lock_count_tid;
144 }
145
get_tl_lock_count_tid_sub(void)146 int get_tl_lock_count_tid_sub(void)
147 {
148 return tl_lock_count_tid_sub;
149 }
150
get_tl_lock_count_fail(void)151 int get_tl_lock_count_fail(void)
152 {
153 return tl_lock_count_fail;
154 }
155
get_thread_list_lock_after_lock(void)156 int get_thread_list_lock_after_lock(void)
157 {
158 return thread_list_lock_after_lock;
159 }
160
get_thread_list_lock_pre_unlock(void)161 int get_thread_list_lock_pre_unlock(void)
162 {
163 return thread_list_lock_pre_unlock;
164 }
165
get_thread_list_lock_pthread_exit(void)166 int get_thread_list_lock_pthread_exit(void)
167 {
168 return thread_list_lock_pthread_exit;
169 }
170
get_thread_list_lock_tid_overlimit(void)171 int get_thread_list_lock_tid_overlimit(void)
172 {
173 return thread_list_lock_tid_overlimit;
174 }
175
get_tl_lock_caller_count(void)176 struct call_tl_lock *get_tl_lock_caller_count(void)
177 {
178 return &tl_lock_caller_count;
179 }
180
get_register_count(void)181 int get_register_count(void)
182 {
183 return register_count;
184 }
185
update_register_count(void)186 void update_register_count(void)
187 {
188 register_count++;
189 }
190
getDlcloseLockStatus()191 pid_t getDlcloseLockStatus()
192 {
193 return g_dlcloseLockStatus;
194 }
195
getDlcloseLockLastExitTid()196 pid_t getDlcloseLockLastExitTid()
197 {
198 return g_dlcloseLockLastExitTid;
199 }
200
setDlcloseLockStatus(pid_t value)201 void setDlcloseLockStatus(pid_t value)
202 {
203 g_dlcloseLockStatus = value;
204 }
205
setDlcloseLockLastExitTid(pid_t value)206 void setDlcloseLockLastExitTid(pid_t value)
207 {
208 g_dlcloseLockLastExitTid = value;
209 }
210
211 #ifdef ENABLE_HWASAN
212 __attribute__((no_sanitize("hwaddress")))
213 #endif
__tl_lock(void)214 void __tl_lock(void)
215 {
216 int tid = __pthread_self()->tid;
217 if (tid == TID_ERROR_0 || tid == TID_ERROR_INIT) {
218 tl_lock_tid_fail = TID_ERROR_0;
219 tid = __syscall(SYS_gettid);
220 }
221 if ((thread_list_lock_pthread_exit == tid) &&
222 (thread_list_lock_pthread_exit == __thread_list_lock)) {
223 thread_list_lock_tid_overlimit = __thread_list_lock;
224 }
225 int val = __thread_list_lock;
226 if (val == tid) {
227 tl_lock_count++;
228 tl_lock_count_tid = val;
229 return;
230 }
231 while ((val = a_cas(&__thread_list_lock, 0, tid)))
232 __wait(&__thread_list_lock, &tl_lock_waiters, val, 0);
233 thread_list_lock_after_lock = __thread_list_lock;
234 if (get_tl_lock_caller_count()) {
235 get_tl_lock_caller_count()->tl_lock_unlock_count++;
236 }
237 }
238
__tl_unlock(void)239 void __tl_unlock(void)
240 {
241 if (tl_lock_count) {
242 tl_lock_count--;
243 tl_lock_count_tid_sub = __thread_list_lock;
244 return;
245 }
246 thread_list_lock_pre_unlock = __thread_list_lock;
247 if (get_tl_lock_caller_count()) {
248 get_tl_lock_caller_count()->tl_lock_unlock_count--;
249 }
250 a_store(&__thread_list_lock, 0);
251 if (tl_lock_waiters) __wake(&__thread_list_lock, 1, 0);
252 }
253
__tl_sync(pthread_t td)254 void __tl_sync(pthread_t td)
255 {
256 a_barrier();
257 int val = __thread_list_lock;
258 if (!val) return;
259 __wait(&__thread_list_lock, &tl_lock_waiters, val, 0);
260 if (tl_lock_waiters) __wake(&__thread_list_lock, 1, 0);
261 }
262
263 #ifdef CXA_THREAD_USE_TLS
264 extern void __cxa_thread_finalize();
265 #endif
266
267 #ifdef ENABLE_HWASAN
268 weak void __hwasan_thread_enter();
269 weak void __hwasan_thread_exit();
270
271 __attribute__((no_sanitize("hwaddress")))
272 #endif
__pthread_exit(void * result)273 _Noreturn void __pthread_exit(void *result)
274 {
275 #ifdef CXA_THREAD_USE_TLS
276 // Call thread_local dtors.
277 __cxa_thread_finalize();
278 #endif
279 pthread_t self = __pthread_self();
280 sigset_t set;
281
282 #ifdef FEATURE_PTHREAD_CANCEL
283 self->canceldisable = 1;
284 self->cancelasync = 0;
285 #endif
286 self->result = result;
287
288 while (self->cancelbuf) {
289 void (*f)(void *) = self->cancelbuf->__f;
290 void *x = self->cancelbuf->__x;
291 self->cancelbuf = self->cancelbuf->__next;
292 f(x);
293 }
294
295 __pthread_tsd_run_dtors();
296
297 __block_app_sigs(&set);
298
299 /* This atomic potentially competes with a concurrent pthread_detach
300 * call; the loser is responsible for freeing thread resources. */
301 int state = a_cas(&self->detach_state, DT_JOINABLE, DT_EXITING);
302
303 if (state==DT_DETACHED && self->map_base) {
304 /* Since __unmapself bypasses the normal munmap code path,
305 * explicitly wait for vmlock holders first. This must be
306 * done before any locks are taken, to avoid lock ordering
307 * issues that could lead to deadlock. */
308 __vm_wait();
309 }
310
311 /* Access to target the exiting thread with syscalls that use
312 * its kernel tid is controlled by killlock. For detached threads,
313 * any use past this point would have undefined behavior, but for
314 * joinable threads it's a valid usage that must be handled.
315 * Signals must be blocked since pthread_kill must be AS-safe. */
316 LOCK(self->killlock);
317
318 /* The thread list lock must be AS-safe, and thus depends on
319 * application signals being blocked above. */
320 __tl_lock();
321 if (get_tl_lock_caller_count()) {
322 get_tl_lock_caller_count()->__pthread_exit_tl_lock++;
323 }
324
325 #ifdef RESERVE_SIGNAL_STACK
326 __pthread_release_signal_stack();
327 #endif
328 /* If this is the only thread in the list, don't proceed with
329 * termination of the thread, but restore the previous lock and
330 * signal state to prepare for exit to call atexit handlers. */
331 if (self->next == self) {
332 if (get_tl_lock_caller_count()) {
333 get_tl_lock_caller_count()->__pthread_exit_tl_lock--;
334 }
335 __tl_unlock();
336 UNLOCK(self->killlock);
337 self->detach_state = state;
338 __restore_sigs(&set);
339 #ifdef ENABLE_HWASAN
340 __hwasan_thread_exit();
341 #endif
342 exit(0);
343 }
344
345 /* At this point we are committed to thread termination. */
346
347 /* After the kernel thread exits, its tid may be reused. Clear it
348 * to prevent inadvertent use and inform functions that would use
349 * it that it's no longer available. At this point the killlock
350 * may be released, since functions that use it will consistently
351 * see the thread as having exited. Release it now so that no
352 * remaining locks (except thread list) are held if we end up
353 * resetting need_locks below. */
354 self->tid = 0;
355 UNLOCK(self->killlock);
356
357 /* Process robust list in userspace to handle non-pshared mutexes
358 * and the detached thread case where the robust list head will
359 * be invalid when the kernel would process it. */
360 __vm_lock();
361 volatile void *volatile *rp;
362 while ((rp=self->robust_list.head) && rp != &self->robust_list.head) {
363 pthread_mutex_t *m = (void *)((char *)rp
364 - offsetof(pthread_mutex_t, _m_next));
365 int waiters = m->_m_waiters;
366 int priv = (m->_m_type & 128) ^ 128;
367 self->robust_list.pending = rp;
368 self->robust_list.head = *rp;
369 int cont = a_swap(&m->_m_lock, 0x40000000);
370 self->robust_list.pending = 0;
371 if (cont < 0 || waiters)
372 __wake(&m->_m_lock, 1, priv);
373 }
374 __vm_unlock();
375
376 __do_orphaned_stdio_locks();
377 __dl_thread_cleanup();
378
379 /* Last, unlink thread from the list. This change will not be visible
380 * until the lock is released, which only happens after SYS_exit
381 * has been called, via the exit futex address pointing at the lock.
382 * This needs to happen after any possible calls to LOCK() that might
383 * skip locking if process appears single-threaded. */
384 if (!--libc.threads_minus_1) libc.need_locks = -1;
385 self->next->prev = self->prev;
386 self->prev->next = self->next;
387 self->prev = self->next = self;
388
389 if (state==DT_DETACHED && self->map_base) {
390 /* Detached threads must block even implementation-internal
391 * signals, since they will not have a stack in their last
392 * moments of existence. */
393 __block_all_sigs(&set);
394
395 /* Robust list will no longer be valid, and was already
396 * processed above, so unregister it with the kernel. */
397 if (self->robust_list.off)
398 __syscall(SYS_set_robust_list, 0, 3*sizeof(long));
399
400 /* The following call unmaps the thread's stack mapping
401 * and then exits without touching the stack. */
402 if (tl_lock_count != 0) {
403 tl_lock_count_fail = tl_lock_count;
404 tl_lock_count = 0;
405 }
406 thread_list_lock_pthread_exit = __thread_list_lock;
407 if (get_tl_lock_caller_count()) {
408 get_tl_lock_caller_count()->__pthread_exit_tl_lock--;
409 get_tl_lock_caller_count()->tl_lock_unlock_count--;
410 }
411 __unmapself(self->map_base, self->map_size);
412 }
413
414 /* Wake any joiner. */
415 a_store(&self->detach_state, DT_EXITED);
416 __wake(&self->detach_state, 1, 1);
417
418 #ifdef ENABLE_HWASAN
419 __hwasan_thread_exit();
420 #endif
421
422 // If a thread call __tl_lock and call __pthread_exit without
423 // call __tl_unlock, the value of tl_lock_count will appear
424 // non-zero value, here set it to zero.
425 if (tl_lock_count != 0) {
426 tl_lock_count_fail = tl_lock_count;
427 tl_lock_count = 0;
428 }
429 thread_list_lock_pthread_exit = __thread_list_lock;
430 if (get_tl_lock_caller_count()) {
431 get_tl_lock_caller_count()->__pthread_exit_tl_lock--;
432 get_tl_lock_caller_count()->tl_lock_unlock_count--;
433 }
434
435 for (;;) __syscall(SYS_exit, 0);
436 }
437
__do_cleanup_push(struct __ptcb * cb)438 void __do_cleanup_push(struct __ptcb *cb)
439 {
440 struct pthread *self = __pthread_self();
441 cb->__next = self->cancelbuf;
442 self->cancelbuf = cb;
443 }
444
__do_cleanup_pop(struct __ptcb * cb)445 void __do_cleanup_pop(struct __ptcb *cb)
446 {
447 __pthread_self()->cancelbuf = cb->__next;
448 }
449
450 struct start_args {
451 void *(*start_func)(void *);
452 void *start_arg;
453 volatile int control;
454 unsigned long sig_mask[_NSIG/8/sizeof(long)];
455 };
456
457 #ifdef ENABLE_HWASAN
458 __attribute__((no_sanitize("hwaddress")))
459 #endif
start(void * p)460 static int start(void *p)
461 {
462 #ifdef ENABLE_HWASAN
463 __hwasan_thread_enter();
464 #endif
465 struct start_args *args = p;
466 int state = args->control;
467 if (state) {
468 if (a_cas(&args->control, 1, 2) == 1)
469 __wait(&args->control, 0, 2, 1);
470 if (args->control) {
471 __syscall(SYS_set_tid_address, &args->control);
472 for (;;) __syscall(SYS_exit, 0);
473 }
474 }
475 __syscall(SYS_rt_sigprocmask, SIG_SETMASK, &args->sig_mask, 0, _NSIG/8);
476 #ifdef RESERVE_SIGNAL_STACK
477 __pthread_reserve_signal_stack();
478 #endif
479 __pthread_exit(args->start_func(args->start_arg));
480 return 0;
481 }
482
483 #ifdef ENABLE_HWASAN
484 __attribute__((no_sanitize("hwaddress")))
485 #endif
start_c11(void * p)486 static int start_c11(void *p)
487 {
488 #ifdef RESERVE_SIGNAL_STACK
489 __pthread_reserve_signal_stack();
490 #endif
491 #ifdef ENABLE_HWASAN
492 __hwasan_thread_enter();
493 #endif
494 struct start_args *args = p;
495 int (*start)(void*) = (int(*)(void*)) args->start_func;
496 __pthread_exit((void *)(uintptr_t)start(args->start_arg));
497 return 0;
498 }
499
500 #define ROUND(x) (((x)+PAGE_SIZE-1)&-PAGE_SIZE)
501
502 /* pthread_key_create.c overrides this */
503 static volatile size_t dummy = 0;
504 weak_alias(dummy, __pthread_tsd_size);
505 static void *dummy_tsd[1] = { 0 };
506 weak_alias(dummy_tsd, __pthread_tsd_main);
507
508 static FILE *volatile dummy_file = 0;
509 weak_alias(dummy_file, __stdin_used);
510 weak_alias(dummy_file, __stdout_used);
511 weak_alias(dummy_file, __stderr_used);
512
init_file_lock(FILE * f)513 static void init_file_lock(FILE *f)
514 {
515 if (f && f->lock<0) f->lock = 0;
516 }
517
518 #ifdef ENABLE_HWASAN
519 __attribute__((no_sanitize("hwaddress")))
520 #endif
__pthread_create(pthread_t * restrict res,const pthread_attr_t * restrict attrp,void * (* entry)(void *),void * restrict arg)521 int __pthread_create(pthread_t *restrict res, const pthread_attr_t *restrict attrp, void *(*entry)(void *), void *restrict arg)
522 {
523 int ret, c11 = (attrp == __ATTRP_C11_THREAD);
524 size_t size, guard;
525 struct pthread *self, *new;
526 unsigned char *map = 0, *stack = 0, *tsd = 0, *stack_limit;
527 unsigned flags = CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND
528 | CLONE_THREAD | CLONE_SYSVSEM | CLONE_SETTLS
529 | CLONE_PARENT_SETTID | CLONE_CHILD_CLEARTID | CLONE_DETACHED;
530 pthread_attr_t attr = { 0 };
531 sigset_t set;
532
533 if (!libc.can_do_threads) {
534 MUSL_LOGW("pthread_create: can't do threads, err: %{public}s", strerror(errno));
535 return ENOSYS;
536 }
537 self = __pthread_self();
538 if (!libc.threaded) {
539 for (FILE *f = *__ofl_lock(); f; f = f->next)
540 init_file_lock(f);
541 __ofl_unlock();
542 init_file_lock(__stdin_used);
543 init_file_lock(__stdout_used);
544 init_file_lock(__stderr_used);
545 __syscall(SYS_rt_sigprocmask, SIG_UNBLOCK, SIGPT_SET, 0, _NSIG/8);
546 self->tsd = (void **)__pthread_tsd_main;
547 __membarrier_init();
548 libc.threaded = 1;
549 }
550 if (attrp && !c11) attr = *attrp;
551
552 __acquire_ptc();
553 if (!attrp || c11) {
554 attr._a_stacksize = __default_stacksize;
555 attr._a_guardsize = __default_guardsize;
556 }
557
558 if (attr._a_stackaddr) {
559 size_t need = libc.tls_size + __pthread_tsd_size;
560 size = attr._a_stacksize;
561 stack = (void *)(attr._a_stackaddr & -16);
562 stack_limit = (void *)(attr._a_stackaddr - size);
563 /* Use application-provided stack for TLS only when
564 * it does not take more than ~12% or 2k of the
565 * application's stack space. */
566 if (need < size / 8 && need < 2048) {
567 tsd = stack - __pthread_tsd_size;
568 stack = tsd - libc.tls_size;
569 memset(stack, 0, need);
570 } else {
571 size = ROUND(need);
572 }
573 guard = 0;
574 } else {
575 guard = ROUND(attr._a_guardsize);
576 size = guard + ROUND(attr._a_stacksize
577 + libc.tls_size + __pthread_tsd_size);
578 }
579
580 if (!tsd) {
581 if (guard) {
582 map = __mmap(0, size, PROT_NONE, MAP_PRIVATE | MAP_ANON, -1, 0);
583 if (map == MAP_FAILED) {
584 MUSL_LOGW("pthread_create: mmap PROT_NONE failed, err:%{public}s", strerror(errno));
585 goto fail;
586 }
587 if (__mprotect(map+guard, size-guard, PROT_READ|PROT_WRITE)
588 && errno != ENOSYS) {
589 MUSL_LOGW("pthread_create: mprotect failed, err:%{public}s", strerror(errno));
590 __munmap(map, size);
591 goto fail;
592 }
593 } else {
594 map = __mmap(0, size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON, -1, 0);
595 if (map == MAP_FAILED) {
596 MUSL_LOGW("pthread_create: mmap PROT_READ|PROT_WRITE failed, err:%{public}s", strerror(errno));
597 goto fail;
598 }
599 }
600 tsd = map + size - __pthread_tsd_size;
601 if (!stack) {
602 stack = tsd - libc.tls_size;
603 stack_limit = map + guard;
604 }
605 }
606
607 new = __copy_tls(tsd - libc.tls_size);
608 new->map_base = map;
609 new->map_size = size;
610 new->stack = stack;
611 new->stack_size = stack - stack_limit;
612 new->guard_size = guard;
613 new->self = new;
614 new->pid = getpid();
615 new->proc_tid = -1;
616 new->tsd = (void *)tsd;
617 new->locale = &libc.global_locale;
618 if (attr._a_detach) {
619 new->detach_state = DT_DETACHED;
620 } else {
621 new->detach_state = DT_JOINABLE;
622 }
623 new->robust_list.head = &new->robust_list.head;
624 new->canary = self->canary;
625 new->sysinfo = self->sysinfo;
626 /* This is for GWP_ASAN to copy the configure to child thread. */
627 new->gwp_asan_tls = self->gwp_asan_tls;
628
629 /* Setup argument structure for the new thread on its stack.
630 * It's safe to access from the caller only until the thread
631 * list is unlocked. */
632 stack -= (uintptr_t)stack % sizeof(uintptr_t);
633 stack -= sizeof(struct start_args);
634 struct start_args *args = (void *)stack;
635 args->start_func = entry;
636 args->start_arg = arg;
637 args->control = attr._a_sched ? 1 : 0;
638
639 /* Application signals (but not the synccall signal) must be
640 * blocked before the thread list lock can be taken, to ensure
641 * that the lock is AS-safe. */
642 __block_app_sigs(&set);
643
644 /* Ensure SIGCANCEL is unblocked in new thread. This requires
645 * working with a copy of the set so we can restore the
646 * original mask in the calling thread. */
647 memcpy(&args->sig_mask, &set, sizeof args->sig_mask);
648 args->sig_mask[(SIGCANCEL-1)/8/sizeof(long)] &=
649 ~(1UL<<((SIGCANCEL-1)%(8*sizeof(long))));
650
651 __tl_lock();
652 if (get_tl_lock_caller_count()) {
653 get_tl_lock_caller_count()->__pthread_create_tl_lock++;
654 }
655 if (!libc.threads_minus_1++) libc.need_locks = 1;
656 ret = __clone((c11 ? start_c11 : start), stack, flags, args, &new->tid, TP_ADJ(new), &__thread_list_lock);
657 int cloneErrno = 0;
658 /* All clone failures translate to EAGAIN. If explicit scheduling
659 * was requested, attempt it before unlocking the thread list so
660 * that the failed thread is never exposed and so that we can
661 * clean up all transient resource usage before returning. */
662 if (ret < 0) {
663 cloneErrno = ret;
664 ret = -EAGAIN;
665 } else if (attr._a_sched) {
666 ret = __syscall(SYS_sched_setscheduler,
667 new->tid, attr._a_policy, &attr._a_prio);
668 if (a_swap(&args->control, ret ? 3 : 0) == 2)
669 __wake(&args->control, 1, 1);
670 if (ret)
671 __wait(&args->control, 0, 3, 0);
672 }
673
674 if (ret >= 0) {
675 stack_naming(new);
676
677 new->next = self->next;
678 new->prev = self;
679 new->next->prev = new;
680 new->prev->next = new;
681 } else {
682 if (!--libc.threads_minus_1) libc.need_locks = 0;
683 }
684 if (get_tl_lock_caller_count()) {
685 get_tl_lock_caller_count()->__pthread_create_tl_lock--;
686 }
687 __tl_unlock();
688 __restore_sigs(&set);
689 __release_ptc();
690
691 if (ret < 0) {
692 if (map) __munmap(map, size);
693 MUSL_LOGW("pthread_create: ret: %{public}d, cloneErrno: %{public}d, err: %{public}s",
694 ret, cloneErrno, strerror(errno));
695 return -ret;
696 }
697
698 *res = new;
699 return 0;
700 fail:
701 __release_ptc();
702 return EAGAIN;
703 }
704
705 weak_alias(__pthread_exit, pthread_exit);
706 weak_alias(__pthread_create, pthread_create);
707
__pthread_list_find(pthread_t thread_id,const char * info)708 struct pthread* __pthread_list_find(pthread_t thread_id, const char* info)
709 {
710 struct pthread *thread = (struct pthread *)thread_id;
711 if (NULL == thread) {
712 log_print("invalid pthread_t (0) passed to %s\n", info);
713 return NULL;
714 }
715
716 struct pthread *self = __pthread_self();
717 if (thread == self) {
718 return thread;
719 }
720 struct pthread *t = self;
721 t = t->next ;
722 while (t != self) {
723 if (t == thread) return thread;
724 t = t->next ;
725 }
726 log_print("invalid pthread_t %p passed to %s\n", thread, info);
727 return NULL;
728 }
729
__pthread_gettid_np(pthread_t t)730 pid_t __pthread_gettid_np(pthread_t t)
731 {
732 sigset_t set;
733 __block_app_sigs(&set);
734 __tl_lock();
735 if (get_tl_lock_caller_count()) {
736 get_tl_lock_caller_count()->__pthread_gettid_np_tl_lock++;
737 }
738 struct pthread* thread = __pthread_list_find(t, "pthread_gettid_np");
739 if (get_tl_lock_caller_count()) {
740 get_tl_lock_caller_count()->__pthread_gettid_np_tl_lock--;
741 }
742 __tl_unlock();
743 __restore_sigs(&set);
744 return thread ? thread->tid : -1;
745 }
746 weak_alias(__pthread_gettid_np, pthread_gettid_np);
747