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);
15 weak_alias(dummy_0, __do_orphaned_stdio_locks);
17 _Noreturn void pthread_exit(void *result)
19 pthread_t self = __pthread_self();
22 self->result = result;
24 while (self->cancelbuf) {
25 void (*f)(void *) = self->cancelbuf->__f;
26 void *x = self->cancelbuf->__x;
27 self->cancelbuf = self->cancelbuf->__next;
31 __pthread_tsd_run_dtors();
33 __lock(self->exitlock);
35 /* Mark this thread dead before decrementing count */
36 __lock(self->killlock);
39 /* Block all signals before decrementing the live thread count.
40 * This is important to ensure that dynamically allocated TLS
41 * is not under-allocated/over-committed, and possibly for other
43 __block_all_sigs(&set);
45 /* Wait to unlock the kill lock, which governs functions like
46 * pthread_kill which target a thread id, until signals have
47 * been blocked. This precludes observation of the thread id
48 * as a live thread (with application code running in it) after
49 * the thread was reported dead by ESRCH being returned. */
50 __unlock(self->killlock);
52 /* It's impossible to determine whether this is "the last thread"
53 * until performing the atomic decrement, since multiple threads
54 * could exit at the same time. For the last thread, revert the
55 * decrement and unblock signals to give the atexit handlers and
56 * stdio cleanup code a consistent state. */
57 if (a_fetch_add(&libc.threads_minus_1, -1)==0) {
58 libc.threads_minus_1 = 0;
63 if (self->locale != &libc.global_locale) {
64 a_dec(&libc.uselocale_cnt);
65 if (self->locale->ctype_utf8)
66 a_dec(&libc.bytelocale_cnt_minus_1);
69 __do_private_robust_list();
70 __do_orphaned_stdio_locks();
72 if (self->detached && self->map_base) {
73 /* Detached threads must avoid the kernel clear_child_tid
74 * feature, since the virtual address will have been
75 * unmapped and possibly already reused by a new mapping
76 * at the time the kernel would perform the write. In
77 * the case of threads that started out detached, the
78 * initial clone flags are correct, but if the thread was
79 * detached later (== 2), we need to clear it here. */
80 if (self->detached == 2) __syscall(SYS_set_tid_address, 0);
82 /* The following call unmaps the thread's stack mapping
83 * and then exits without touching the stack. */
84 __unmapself(self->map_base, self->map_size);
87 for (;;) __syscall(SYS_exit, 0);
90 void __do_cleanup_push(struct __ptcb *cb)
92 if (!libc.has_thread_pointer) return;
93 struct pthread *self = __pthread_self();
94 cb->__next = self->cancelbuf;
98 void __do_cleanup_pop(struct __ptcb *cb)
100 if (!libc.has_thread_pointer) return;
101 __pthread_self()->cancelbuf = cb->__next;
104 static int start(void *p)
107 if (self->startlock[0]) {
108 __wait(self->startlock, 0, 1, 1);
109 if (self->startlock[0]) {
113 __restore_sigs(self->sigmask);
115 if (self->unblock_cancel)
116 __syscall(SYS_rt_sigprocmask, SIG_UNBLOCK,
117 SIGPT_SET, 0, _NSIG/8);
118 pthread_exit(self->start(self->start_arg));
122 #define ROUND(x) (((x)+PAGE_SIZE-1)&-PAGE_SIZE)
124 /* pthread_key_create.c overrides this */
125 static volatile size_t dummy = 0;
126 weak_alias(dummy, __pthread_tsd_size);
127 static void *dummy_tsd[1] = { 0 };
128 weak_alias(dummy_tsd, __pthread_tsd_main);
130 static FILE *volatile dummy_file = 0;
131 weak_alias(dummy_file, __stdin_used);
132 weak_alias(dummy_file, __stdout_used);
133 weak_alias(dummy_file, __stderr_used);
135 static void init_file_lock(FILE *f)
137 if (f && f->lock<0) f->lock = 0;
140 void *__copy_tls(unsigned char *);
142 int pthread_create(pthread_t *restrict res, const pthread_attr_t *restrict attrp, void *(*entry)(void *), void *restrict arg)
146 struct pthread *self, *new;
147 unsigned char *map = 0, *stack = 0, *tsd = 0, *stack_limit;
148 unsigned flags = CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND
149 | CLONE_THREAD | CLONE_SYSVSEM | CLONE_SETTLS
150 | CLONE_PARENT_SETTID | CLONE_CHILD_CLEARTID | CLONE_DETACHED;
152 pthread_attr_t attr = {0};
154 if (!libc.can_do_threads) return ENOSYS;
155 self = __pthread_self();
156 if (!libc.threaded) {
157 for (FILE *f=libc.ofl_head; f; f=f->next)
159 init_file_lock(__stdin_used);
160 init_file_lock(__stdout_used);
161 init_file_lock(__stderr_used);
162 __syscall(SYS_rt_sigprocmask, SIG_UNBLOCK, SIGPT_SET, 0, _NSIG/8);
163 self->tsd = (void **)__pthread_tsd_main;
166 if (attrp) attr = *attrp;
170 if (attr._a_stackaddr) {
171 size_t need = libc.tls_size + __pthread_tsd_size;
172 size = attr._a_stacksize + DEFAULT_STACK_SIZE;
173 stack = (void *)(attr._a_stackaddr & -16);
174 stack_limit = (void *)(attr._a_stackaddr - size);
175 /* Use application-provided stack for TLS only when
176 * it does not take more than ~12% or 2k of the
177 * application's stack space. */
178 if (need < size/8 && need < 2048) {
179 tsd = stack - __pthread_tsd_size;
180 stack = tsd - libc.tls_size;
181 memset(stack, 0, need);
187 guard = ROUND(DEFAULT_GUARD_SIZE + attr._a_guardsize);
188 size = guard + ROUND(DEFAULT_STACK_SIZE + attr._a_stacksize
189 + libc.tls_size + __pthread_tsd_size);
194 map = mmap(0, size, PROT_NONE, MAP_PRIVATE|MAP_ANON, -1, 0);
195 if (map == MAP_FAILED) goto fail;
196 if (mprotect(map+guard, size-guard, PROT_READ|PROT_WRITE)) {
201 map = mmap(0, size, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANON, -1, 0);
202 if (map == MAP_FAILED) goto fail;
204 tsd = map + size - __pthread_tsd_size;
206 stack = tsd - libc.tls_size;
207 stack_limit = map + guard;
211 new = __copy_tls(tsd - libc.tls_size);
213 new->map_size = size;
215 new->stack_size = stack - stack_limit;
217 new->start_arg = arg;
219 new->tsd = (void *)tsd;
220 new->locale = &libc.global_locale;
221 if (attr._a_detach) {
223 flags -= CLONE_CHILD_CLEARTID;
226 do_sched = new->startlock[0] = 1;
227 __block_app_sigs(new->sigmask);
229 new->unblock_cancel = self->cancel;
230 new->canary = self->canary;
232 a_inc(&libc.threads_minus_1);
233 ret = __clone(start, stack, flags, new, &new->tid, TP_ADJ(new), &new->tid);
238 __restore_sigs(new->sigmask);
242 a_dec(&libc.threads_minus_1);
243 if (map) munmap(map, size);
248 ret = __syscall(SYS_sched_setscheduler, new->tid,
249 attr._a_policy, &attr._a_prio);
250 a_store(new->startlock, ret<0 ? 2 : 0);
251 __wake(new->startlock, 1, 1);
252 if (ret < 0) return -ret;