1 #include "pthread_impl.h"
2 #include "stdio_impl.h"
8 weak_alias(dummy_0, __acquire_ptc);
9 weak_alias(dummy_0, __release_ptc);
10 weak_alias(dummy_0, __pthread_tsd_run_dtors);
12 _Noreturn void pthread_exit(void *result)
14 pthread_t self = pthread_self();
17 self->result = result;
19 while (self->cancelbuf) {
20 void (*f)(void *) = self->cancelbuf->__f;
21 void *x = self->cancelbuf->__x;
22 self->cancelbuf = self->cancelbuf->__next;
26 __pthread_tsd_run_dtors();
28 __lock(self->exitlock);
30 /* Mark this thread dead before decrementing count */
31 __lock(self->killlock);
34 /* Block all signals before decrementing the live thread count.
35 * This is important to ensure that dynamically allocated TLS
36 * is not under-allocated/over-committed, and possibly for other
38 __block_all_sigs(&set);
40 /* Wait to unlock the kill lock, which governs functions like
41 * pthread_kill which target a thread id, until signals have
42 * been blocked. This precludes observation of the thread id
43 * as a live thread (with application code running in it) after
44 * the thread was reported dead by ESRCH being returned. */
45 __unlock(self->killlock);
47 /* It's impossible to determine whether this is "the last thread"
48 * until performing the atomic decrement, since multiple threads
49 * could exit at the same time. For the last thread, revert the
50 * decrement and unblock signals to give the atexit handlers and
51 * stdio cleanup code a consistent state. */
52 if (a_fetch_add(&libc.threads_minus_1, -1)==0) {
53 libc.threads_minus_1 = 0;
58 if (self->detached && self->map_base) {
59 /* Detached threads must avoid the kernel clear_child_tid
60 * feature, since the virtual address will have been
61 * unmapped and possibly already reused by a new mapping
62 * at the time the kernel would perform the write. In
63 * the case of threads that started out detached, the
64 * initial clone flags are correct, but if the thread was
65 * detached later (== 2), we need to clear it here. */
66 if (self->detached == 2) __syscall(SYS_set_tid_address, 0);
68 /* The following call unmaps the thread's stack mapping
69 * and then exits without touching the stack. */
70 __unmapself(self->map_base, self->map_size);
73 for (;;) __syscall(SYS_exit, 0);
76 void __do_cleanup_push(struct __ptcb *cb)
78 struct pthread *self = pthread_self();
79 cb->__next = self->cancelbuf;
83 void __do_cleanup_pop(struct __ptcb *cb)
85 __pthread_self()->cancelbuf = cb->__next;
88 static int start(void *p)
91 if (self->startlock[0]) {
92 __wait(self->startlock, 0, 1, 1);
93 if (self->startlock[0]) {
97 __restore_sigs(self->sigmask);
99 if (self->unblock_cancel)
100 __syscall(SYS_rt_sigprocmask, SIG_UNBLOCK,
101 SIGPT_SET, 0, _NSIG/8);
102 pthread_exit(self->start(self->start_arg));
106 #define ROUND(x) (((x)+PAGE_SIZE-1)&-PAGE_SIZE)
108 /* pthread_key_create.c overrides this */
109 static const size_t dummy = 0;
110 weak_alias(dummy, __pthread_tsd_size);
112 static FILE *const dummy_file = 0;
113 weak_alias(dummy_file, __stdin_used);
114 weak_alias(dummy_file, __stdout_used);
115 weak_alias(dummy_file, __stderr_used);
117 static void init_file_lock(FILE *f)
119 if (f && f->lock<0) f->lock = 0;
122 void *__copy_tls(unsigned char *);
124 int pthread_create(pthread_t *restrict res, const pthread_attr_t *restrict attrp, void *(*entry)(void *), void *restrict arg)
128 struct pthread *self = pthread_self(), *new;
129 unsigned char *map = 0, *stack = 0, *tsd = 0, *stack_limit;
130 unsigned flags = 0x7d8f00;
132 pthread_attr_t attr = {0};
134 if (!self) return ENOSYS;
135 if (!libc.threaded) {
136 for (FILE *f=libc.ofl_head; f; f=f->next)
138 init_file_lock(__stdin_used);
139 init_file_lock(__stdout_used);
140 init_file_lock(__stderr_used);
143 if (attrp) attr = *attrp;
147 if (attr._a_stackaddr) {
148 size_t need = libc.tls_size + __pthread_tsd_size;
149 size = attr._a_stacksize + DEFAULT_STACK_SIZE;
150 stack = (void *)(attr._a_stackaddr & -16);
151 stack_limit = (void *)(attr._a_stackaddr - size);
152 /* Use application-provided stack for TLS only when
153 * it does not take more than ~12% or 2k of the
154 * application's stack space. */
155 if (need < size/8 && need < 2048) {
156 tsd = stack - __pthread_tsd_size;
157 stack = tsd - libc.tls_size;
163 guard = ROUND(DEFAULT_GUARD_SIZE + attr._a_guardsize);
164 size = guard + ROUND(DEFAULT_STACK_SIZE + attr._a_stacksize
165 + libc.tls_size + __pthread_tsd_size);
170 map = mmap(0, size, PROT_NONE, MAP_PRIVATE|MAP_ANON, -1, 0);
171 if (map == MAP_FAILED) goto fail;
172 if (mprotect(map+guard, size-guard, PROT_READ|PROT_WRITE)) {
177 map = mmap(0, size, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANON, -1, 0);
178 if (map == MAP_FAILED) goto fail;
180 tsd = map + size - __pthread_tsd_size;
182 stack = tsd - libc.tls_size;
183 stack_limit = map + guard;
187 new = __copy_tls(tsd - libc.tls_size);
189 new->map_size = size;
191 new->stack_size = stack - stack_limit;
192 new->pid = self->pid;
193 new->errno_ptr = &new->errno_val;
195 new->start_arg = arg;
197 new->tsd = (void *)tsd;
198 if (attr._a_detach) {
203 do_sched = new->startlock[0] = 1;
204 __block_app_sigs(new->sigmask);
206 new->unblock_cancel = self->cancel;
207 new->canary = self->canary;
209 a_inc(&libc.threads_minus_1);
210 ret = __clone(start, stack, flags, new, &new->tid, TP_ADJ(new), &new->tid);
215 __restore_sigs(new->sigmask);
219 a_dec(&libc.threads_minus_1);
220 if (map) munmap(map, size);
225 ret = __syscall(SYS_sched_setscheduler, new->tid,
226 attr._a_policy, &attr._a_prio);
227 a_store(new->startlock, ret<0 ? 2 : 0);
228 __wake(new->startlock, 1, 1);
229 if (ret < 0) return -ret;