2 #include "pthread_impl.h"
3 #include "stdio_impl.h"
11 weak_alias(dummy_0, __acquire_ptc);
12 weak_alias(dummy_0, __release_ptc);
13 weak_alias(dummy_0, __pthread_tsd_run_dtors);
14 weak_alias(dummy_0, __do_private_robust_list);
16 _Noreturn void pthread_exit(void *result)
18 pthread_t self = __pthread_self();
21 self->result = result;
23 while (self->cancelbuf) {
24 void (*f)(void *) = self->cancelbuf->__f;
25 void *x = self->cancelbuf->__x;
26 self->cancelbuf = self->cancelbuf->__next;
30 __pthread_tsd_run_dtors();
32 __lock(self->exitlock);
34 /* Mark this thread dead before decrementing count */
35 __lock(self->killlock);
38 /* Block all signals before decrementing the live thread count.
39 * This is important to ensure that dynamically allocated TLS
40 * is not under-allocated/over-committed, and possibly for other
42 __block_all_sigs(&set);
44 /* Wait to unlock the kill lock, which governs functions like
45 * pthread_kill which target a thread id, until signals have
46 * been blocked. This precludes observation of the thread id
47 * as a live thread (with application code running in it) after
48 * the thread was reported dead by ESRCH being returned. */
49 __unlock(self->killlock);
51 /* It's impossible to determine whether this is "the last thread"
52 * until performing the atomic decrement, since multiple threads
53 * could exit at the same time. For the last thread, revert the
54 * decrement and unblock signals to give the atexit handlers and
55 * stdio cleanup code a consistent state. */
56 if (a_fetch_add(&libc.threads_minus_1, -1)==0) {
57 libc.threads_minus_1 = 0;
62 if (self->locale != &libc.global_locale) {
63 a_dec(&libc.uselocale_cnt);
64 if (self->locale->ctype_utf8)
65 a_dec(&libc.bytelocale_cnt_minus_1);
68 __do_private_robust_list();
70 if (self->detached && self->map_base) {
71 /* Detached threads must avoid the kernel clear_child_tid
72 * feature, since the virtual address will have been
73 * unmapped and possibly already reused by a new mapping
74 * at the time the kernel would perform the write. In
75 * the case of threads that started out detached, the
76 * initial clone flags are correct, but if the thread was
77 * detached later (== 2), we need to clear it here. */
78 if (self->detached == 2) __syscall(SYS_set_tid_address, 0);
80 /* The following call unmaps the thread's stack mapping
81 * and then exits without touching the stack. */
82 __unmapself(self->map_base, self->map_size);
85 for (;;) __syscall(SYS_exit, 0);
88 void __do_cleanup_push(struct __ptcb *cb)
90 if (!libc.has_thread_pointer) return;
91 struct pthread *self = __pthread_self();
92 cb->__next = self->cancelbuf;
96 void __do_cleanup_pop(struct __ptcb *cb)
98 if (!libc.has_thread_pointer) return;
99 __pthread_self()->cancelbuf = cb->__next;
102 static int start(void *p)
105 if (self->startlock[0]) {
106 __wait(self->startlock, 0, 1, 1);
107 if (self->startlock[0]) {
111 __restore_sigs(self->sigmask);
113 if (self->unblock_cancel)
114 __syscall(SYS_rt_sigprocmask, SIG_UNBLOCK,
115 SIGPT_SET, 0, _NSIG/8);
116 pthread_exit(self->start(self->start_arg));
120 #define ROUND(x) (((x)+PAGE_SIZE-1)&-PAGE_SIZE)
122 /* pthread_key_create.c overrides this */
123 static volatile size_t dummy = 0;
124 weak_alias(dummy, __pthread_tsd_size);
125 static void *dummy_tsd[1] = { 0 };
126 weak_alias(dummy_tsd, __pthread_tsd_main);
128 static FILE *volatile dummy_file = 0;
129 weak_alias(dummy_file, __stdin_used);
130 weak_alias(dummy_file, __stdout_used);
131 weak_alias(dummy_file, __stderr_used);
133 static void init_file_lock(FILE *f)
135 if (f && f->lock<0) f->lock = 0;
138 void *__copy_tls(unsigned char *);
140 int pthread_create(pthread_t *restrict res, const pthread_attr_t *restrict attrp, void *(*entry)(void *), void *restrict arg)
144 struct pthread *self, *new;
145 unsigned char *map = 0, *stack = 0, *tsd = 0, *stack_limit;
146 unsigned flags = CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND
147 | CLONE_THREAD | CLONE_SYSVSEM | CLONE_SETTLS
148 | CLONE_PARENT_SETTID | CLONE_CHILD_CLEARTID | CLONE_DETACHED;
150 pthread_attr_t attr = {0};
152 if (!libc.can_do_threads) return ENOSYS;
153 self = __pthread_self();
154 if (!libc.threaded) {
155 for (FILE *f=libc.ofl_head; f; f=f->next)
157 init_file_lock(__stdin_used);
158 init_file_lock(__stdout_used);
159 init_file_lock(__stderr_used);
160 __syscall(SYS_rt_sigprocmask, SIG_UNBLOCK, SIGPT_SET, 0, _NSIG/8);
161 self->tsd = (void **)__pthread_tsd_main;
164 if (attrp) attr = *attrp;
168 if (attr._a_stackaddr) {
169 size_t need = libc.tls_size + __pthread_tsd_size;
170 size = attr._a_stacksize + DEFAULT_STACK_SIZE;
171 stack = (void *)(attr._a_stackaddr & -16);
172 stack_limit = (void *)(attr._a_stackaddr - size);
173 /* Use application-provided stack for TLS only when
174 * it does not take more than ~12% or 2k of the
175 * application's stack space. */
176 if (need < size/8 && need < 2048) {
177 tsd = stack - __pthread_tsd_size;
178 stack = tsd - libc.tls_size;
179 memset(stack, 0, need);
185 guard = ROUND(DEFAULT_GUARD_SIZE + attr._a_guardsize);
186 size = guard + ROUND(DEFAULT_STACK_SIZE + attr._a_stacksize
187 + libc.tls_size + __pthread_tsd_size);
192 map = mmap(0, size, PROT_NONE, MAP_PRIVATE|MAP_ANON, -1, 0);
193 if (map == MAP_FAILED) goto fail;
194 if (mprotect(map+guard, size-guard, PROT_READ|PROT_WRITE)) {
199 map = mmap(0, size, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANON, -1, 0);
200 if (map == MAP_FAILED) goto fail;
202 tsd = map + size - __pthread_tsd_size;
204 stack = tsd - libc.tls_size;
205 stack_limit = map + guard;
209 new = __copy_tls(tsd - libc.tls_size);
211 new->map_size = size;
213 new->stack_size = stack - stack_limit;
215 new->start_arg = arg;
217 new->tsd = (void *)tsd;
218 new->locale = &libc.global_locale;
219 if (attr._a_detach) {
221 flags -= CLONE_CHILD_CLEARTID;
224 do_sched = new->startlock[0] = 1;
225 __block_app_sigs(new->sigmask);
227 new->unblock_cancel = self->cancel;
228 new->canary = self->canary;
230 a_inc(&libc.threads_minus_1);
231 ret = __clone(start, stack, flags, new, &new->tid, TP_ADJ(new), &new->tid);
236 __restore_sigs(new->sigmask);
240 a_dec(&libc.threads_minus_1);
241 if (map) munmap(map, size);
246 ret = __syscall(SYS_sched_setscheduler, new->tid,
247 attr._a_policy, &attr._a_prio);
248 a_store(new->startlock, ret<0 ? 2 : 0);
249 __wake(new->startlock, 1, 1);
250 if (ret < 0) return -ret;