2 #include "pthread_impl.h"
3 #include "stdio_impl.h"
10 weak_alias(dummy_0, __acquire_ptc);
11 weak_alias(dummy_0, __release_ptc);
12 weak_alias(dummy_0, __pthread_tsd_run_dtors);
13 weak_alias(dummy_0, __do_private_robust_list);
15 _Noreturn void pthread_exit(void *result)
17 pthread_t self = __pthread_self();
20 self->result = result;
22 while (self->cancelbuf) {
23 void (*f)(void *) = self->cancelbuf->__f;
24 void *x = self->cancelbuf->__x;
25 self->cancelbuf = self->cancelbuf->__next;
29 __pthread_tsd_run_dtors();
31 __lock(self->exitlock);
33 /* Mark this thread dead before decrementing count */
34 __lock(self->killlock);
37 /* Block all signals before decrementing the live thread count.
38 * This is important to ensure that dynamically allocated TLS
39 * is not under-allocated/over-committed, and possibly for other
41 __block_all_sigs(&set);
43 /* Wait to unlock the kill lock, which governs functions like
44 * pthread_kill which target a thread id, until signals have
45 * been blocked. This precludes observation of the thread id
46 * as a live thread (with application code running in it) after
47 * the thread was reported dead by ESRCH being returned. */
48 __unlock(self->killlock);
50 /* It's impossible to determine whether this is "the last thread"
51 * until performing the atomic decrement, since multiple threads
52 * could exit at the same time. For the last thread, revert the
53 * decrement and unblock signals to give the atexit handlers and
54 * stdio cleanup code a consistent state. */
55 if (a_fetch_add(&libc.threads_minus_1, -1)==0) {
56 libc.threads_minus_1 = 0;
61 if (self->locale != &libc.global_locale) {
62 a_dec(&libc.uselocale_cnt);
63 if (self->locale->ctype_utf8)
64 a_dec(&libc.bytelocale_cnt_minus_1);
67 __do_private_robust_list();
69 if (self->detached && self->map_base) {
70 /* Detached threads must avoid the kernel clear_child_tid
71 * feature, since the virtual address will have been
72 * unmapped and possibly already reused by a new mapping
73 * at the time the kernel would perform the write. In
74 * the case of threads that started out detached, the
75 * initial clone flags are correct, but if the thread was
76 * detached later (== 2), we need to clear it here. */
77 if (self->detached == 2) __syscall(SYS_set_tid_address, 0);
79 /* The following call unmaps the thread's stack mapping
80 * and then exits without touching the stack. */
81 __unmapself(self->map_base, self->map_size);
84 for (;;) __syscall(SYS_exit, 0);
87 void __do_cleanup_push(struct __ptcb *cb)
89 if (!libc.has_thread_pointer) return;
90 struct pthread *self = __pthread_self();
91 cb->__next = self->cancelbuf;
95 void __do_cleanup_pop(struct __ptcb *cb)
97 if (!libc.has_thread_pointer) return;
98 __pthread_self()->cancelbuf = cb->__next;
101 static int start(void *p)
104 if (self->startlock[0]) {
105 __wait(self->startlock, 0, 1, 1);
106 if (self->startlock[0]) {
110 __restore_sigs(self->sigmask);
112 if (self->unblock_cancel)
113 __syscall(SYS_rt_sigprocmask, SIG_UNBLOCK,
114 SIGPT_SET, 0, _NSIG/8);
115 pthread_exit(self->start(self->start_arg));
119 #define ROUND(x) (((x)+PAGE_SIZE-1)&-PAGE_SIZE)
121 /* pthread_key_create.c overrides this */
122 static volatile size_t dummy = 0;
123 weak_alias(dummy, __pthread_tsd_size);
124 static void *dummy_tsd[1] = { 0 };
125 weak_alias(dummy_tsd, __pthread_tsd_main);
127 static FILE *volatile dummy_file = 0;
128 weak_alias(dummy_file, __stdin_used);
129 weak_alias(dummy_file, __stdout_used);
130 weak_alias(dummy_file, __stderr_used);
132 static void init_file_lock(FILE *f)
134 if (f && f->lock<0) f->lock = 0;
137 void *__copy_tls(unsigned char *);
139 int pthread_create(pthread_t *restrict res, const pthread_attr_t *restrict attrp, void *(*entry)(void *), void *restrict arg)
143 struct pthread *self, *new;
144 unsigned char *map = 0, *stack = 0, *tsd = 0, *stack_limit;
145 unsigned flags = CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND
146 | CLONE_THREAD | CLONE_SYSVSEM | CLONE_SETTLS
147 | CLONE_PARENT_SETTID | CLONE_CHILD_CLEARTID | CLONE_DETACHED;
149 pthread_attr_t attr = {0};
151 if (!libc.can_do_threads) return ENOSYS;
152 self = __pthread_self();
153 if (!libc.threaded) {
154 for (FILE *f=libc.ofl_head; f; f=f->next)
156 init_file_lock(__stdin_used);
157 init_file_lock(__stdout_used);
158 init_file_lock(__stderr_used);
159 __syscall(SYS_rt_sigprocmask, SIG_UNBLOCK, SIGPT_SET, 0, _NSIG/8);
160 self->tsd = (void **)__pthread_tsd_main;
163 if (attrp) attr = *attrp;
167 if (attr._a_stackaddr) {
168 size_t need = libc.tls_size + __pthread_tsd_size;
169 size = attr._a_stacksize + DEFAULT_STACK_SIZE;
170 stack = (void *)(attr._a_stackaddr & -16);
171 stack_limit = (void *)(attr._a_stackaddr - size);
172 /* Use application-provided stack for TLS only when
173 * it does not take more than ~12% or 2k of the
174 * application's stack space. */
175 if (need < size/8 && need < 2048) {
176 tsd = stack - __pthread_tsd_size;
177 stack = tsd - libc.tls_size;
183 guard = ROUND(DEFAULT_GUARD_SIZE + attr._a_guardsize);
184 size = guard + ROUND(DEFAULT_STACK_SIZE + attr._a_stacksize
185 + libc.tls_size + __pthread_tsd_size);
190 map = mmap(0, size, PROT_NONE, MAP_PRIVATE|MAP_ANON, -1, 0);
191 if (map == MAP_FAILED) goto fail;
192 if (mprotect(map+guard, size-guard, PROT_READ|PROT_WRITE)) {
197 map = mmap(0, size, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANON, -1, 0);
198 if (map == MAP_FAILED) goto fail;
200 tsd = map + size - __pthread_tsd_size;
202 stack = tsd - libc.tls_size;
203 stack_limit = map + guard;
207 new = __copy_tls(tsd - libc.tls_size);
209 new->map_size = size;
211 new->stack_size = stack - stack_limit;
213 new->start_arg = arg;
215 new->tsd = (void *)tsd;
216 new->locale = &libc.global_locale;
217 if (attr._a_detach) {
219 flags -= CLONE_CHILD_CLEARTID;
222 do_sched = new->startlock[0] = 1;
223 __block_app_sigs(new->sigmask);
225 new->unblock_cancel = self->cancel;
226 new->canary = self->canary;
228 a_inc(&libc.threads_minus_1);
229 ret = __clone(start, stack, flags, new, &new->tid, TP_ADJ(new), &new->tid);
234 __restore_sigs(new->sigmask);
238 a_dec(&libc.threads_minus_1);
239 if (map) munmap(map, size);
244 ret = __syscall(SYS_sched_setscheduler, new->tid,
245 attr._a_policy, &attr._a_prio);
246 a_store(new->startlock, ret<0 ? 2 : 0);
247 __wake(new->startlock, 1, 1);
248 if (ret < 0) return -ret;