+#define _GNU_SOURCE
#include "pthread_impl.h"
#include "stdio_impl.h"
+#include "libc.h"
#include <sys/mman.h>
+#include <string.h>
+#include <stddef.h>
+
+void *__mmap(void *, size_t, int, int, int, off_t);
+int __munmap(void *, size_t);
+int __mprotect(void *, size_t, int);
static void dummy_0()
{
weak_alias(dummy_0, __acquire_ptc);
weak_alias(dummy_0, __release_ptc);
weak_alias(dummy_0, __pthread_tsd_run_dtors);
+weak_alias(dummy_0, __do_orphaned_stdio_locks);
+weak_alias(dummy_0, __dl_thread_cleanup);
-_Noreturn void pthread_exit(void *result)
+_Noreturn void __pthread_exit(void *result)
{
- pthread_t self = pthread_self();
- int n;
+ pthread_t self = __pthread_self();
+ sigset_t set;
+ self->canceldisable = 1;
+ self->cancelasync = 0;
self->result = result;
while (self->cancelbuf) {
__pthread_tsd_run_dtors();
- __lock(self->exitlock);
+ LOCK(self->exitlock);
/* Mark this thread dead before decrementing count */
- __lock(self->killlock);
+ LOCK(self->killlock);
self->dead = 1;
- __unlock(self->killlock);
- __syscall(SYS_rt_sigprocmask, SIG_BLOCK, SIGALL_SET, 0, _NSIG/8);
+ /* Block all signals before decrementing the live thread count.
+ * This is important to ensure that dynamically allocated TLS
+ * is not under-allocated/over-committed, and possibly for other
+ * reasons as well. */
+ __block_all_sigs(&set);
+
+ /* Wait to unlock the kill lock, which governs functions like
+ * pthread_kill which target a thread id, until signals have
+ * been blocked. This precludes observation of the thread id
+ * as a live thread (with application code running in it) after
+ * the thread was reported dead by ESRCH being returned. */
+ UNLOCK(self->killlock);
- do n = libc.threads_minus_1;
- while (n && a_cas(&libc.threads_minus_1, n, n-1)!=n);
- if (!n) exit(0);
+ /* It's impossible to determine whether this is "the last thread"
+ * until performing the atomic decrement, since multiple threads
+ * could exit at the same time. For the last thread, revert the
+ * decrement and unblock signals to give the atexit handlers and
+ * stdio cleanup code a consistent state. */
+ if (a_fetch_add(&libc.threads_minus_1, -1)==0) {
+ libc.threads_minus_1 = 0;
+ __restore_sigs(&set);
+ exit(0);
+ }
+
+ /* Process robust list in userspace to handle non-pshared mutexes
+ * and the detached thread case where the robust list head will
+ * be invalid when the kernel would process it. */
+ __vm_lock();
+ volatile void *volatile *rp;
+ while ((rp=self->robust_list.head) && rp != &self->robust_list.head) {
+ pthread_mutex_t *m = (void *)((char *)rp
+ - offsetof(pthread_mutex_t, _m_next));
+ int waiters = m->_m_waiters;
+ int priv = (m->_m_type & 128) ^ 128;
+ self->robust_list.pending = rp;
+ self->robust_list.head = *rp;
+ int cont = a_swap(&m->_m_lock, 0x40000000);
+ self->robust_list.pending = 0;
+ if (cont < 0 || waiters)
+ __wake(&m->_m_lock, 1, priv);
+ }
+ __vm_unlock();
+
+ __do_orphaned_stdio_locks();
+ __dl_thread_cleanup();
if (self->detached && self->map_base) {
- if (self->detached == 2)
- __syscall(SYS_set_tid_address, 0);
+ /* Detached threads must avoid the kernel clear_child_tid
+ * feature, since the virtual address will have been
+ * unmapped and possibly already reused by a new mapping
+ * at the time the kernel would perform the write. In
+ * the case of threads that started out detached, the
+ * initial clone flags are correct, but if the thread was
+ * detached later (== 2), we need to clear it here. */
+ if (self->detached == 2) __syscall(SYS_set_tid_address, 0);
+
+ /* Robust list will no longer be valid, and was already
+ * processed above, so unregister it with the kernel. */
+ if (self->robust_list.off)
+ __syscall(SYS_set_robust_list, 0, 3*sizeof(long));
+
+ /* Since __unmapself bypasses the normal munmap code path,
+ * explicitly wait for vmlock holders first. */
+ __vm_wait();
+
+ /* The following call unmaps the thread's stack mapping
+ * and then exits without touching the stack. */
__unmapself(self->map_base, self->map_size);
}
void __do_cleanup_push(struct __ptcb *cb)
{
- struct pthread *self = pthread_self();
+ struct pthread *self = __pthread_self();
cb->__next = self->cancelbuf;
self->cancelbuf = cb;
}
static int start(void *p)
{
pthread_t self = p;
+ /* States for startlock:
+ * 0 = no need for start sync
+ * 1 = waiting for parent to do work
+ * 2 = failure in parent, child must abort
+ * 3 = success in parent, child must restore sigmask */
if (self->startlock[0]) {
__wait(self->startlock, 0, 1, 1);
- if (self->startlock[0]) {
+ if (self->startlock[0] == 2) {
self->detached = 2;
pthread_exit(0);
}
- __syscall(SYS_rt_sigprocmask, SIG_SETMASK,
- self->sigmask, 0, _NSIG/8);
+ __restore_sigs(self->sigmask);
}
if (self->unblock_cancel)
__syscall(SYS_rt_sigprocmask, SIG_UNBLOCK,
SIGPT_SET, 0, _NSIG/8);
- pthread_exit(self->start(self->start_arg));
+ __pthread_exit(self->start(self->start_arg));
+ return 0;
+}
+
+static int start_c11(void *p)
+{
+ pthread_t self = p;
+ int (*start)(void*) = (int(*)(void*)) self->start;
+ __pthread_exit((void *)(uintptr_t)start(self->start_arg));
return 0;
}
#define ROUND(x) (((x)+PAGE_SIZE-1)&-PAGE_SIZE)
/* pthread_key_create.c overrides this */
-static const size_t dummy = 0;
+static volatile size_t dummy = 0;
weak_alias(dummy, __pthread_tsd_size);
+static void *dummy_tsd[1] = { 0 };
+weak_alias(dummy_tsd, __pthread_tsd_main);
-static FILE *const dummy_file = 0;
+volatile int __block_new_threads = 0;
+size_t __default_stacksize = DEFAULT_STACK_SIZE;
+size_t __default_guardsize = DEFAULT_GUARD_SIZE;
+
+static FILE *volatile dummy_file = 0;
weak_alias(dummy_file, __stdin_used);
weak_alias(dummy_file, __stdout_used);
weak_alias(dummy_file, __stderr_used);
void *__copy_tls(unsigned char *);
-int pthread_create(pthread_t *restrict res, const pthread_attr_t *restrict attrp, void *(*entry)(void *), void *restrict arg)
+int __pthread_create(pthread_t *restrict res, const pthread_attr_t *restrict attrp, void *(*entry)(void *), void *restrict arg)
{
- int ret;
+ int ret, c11 = (attrp == __ATTRP_C11_THREAD);
size_t size, guard;
- struct pthread *self = pthread_self(), *new;
+ struct pthread *self, *new;
unsigned char *map = 0, *stack = 0, *tsd = 0, *stack_limit;
- unsigned flags = 0x7d8f00;
+ unsigned flags = CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND
+ | CLONE_THREAD | CLONE_SYSVSEM | CLONE_SETTLS
+ | CLONE_PARENT_SETTID | CLONE_CHILD_CLEARTID | CLONE_DETACHED;
int do_sched = 0;
- pthread_attr_t attr = {0};
+ pthread_attr_t attr = { 0 };
- if (!self) return ENOSYS;
+ if (!libc.can_do_threads) return ENOSYS;
+ self = __pthread_self();
if (!libc.threaded) {
- for (FILE *f=libc.ofl_head; f; f=f->next)
+ for (FILE *f=*__ofl_lock(); f; f=f->next)
init_file_lock(f);
+ __ofl_unlock();
init_file_lock(__stdin_used);
init_file_lock(__stdout_used);
init_file_lock(__stderr_used);
+ __syscall(SYS_rt_sigprocmask, SIG_UNBLOCK, SIGPT_SET, 0, _NSIG/8);
+ self->tsd = (void **)__pthread_tsd_main;
libc.threaded = 1;
}
- if (attrp) attr = *attrp;
+ if (attrp && !c11) attr = *attrp;
__acquire_ptc();
+ if (!attrp || c11) {
+ attr._a_stacksize = __default_stacksize;
+ attr._a_guardsize = __default_guardsize;
+ }
+
+ if (__block_new_threads) __wait(&__block_new_threads, 0, 1, 1);
if (attr._a_stackaddr) {
size_t need = libc.tls_size + __pthread_tsd_size;
- size = attr._a_stacksize + DEFAULT_STACK_SIZE;
+ size = attr._a_stacksize;
stack = (void *)(attr._a_stackaddr & -16);
stack_limit = (void *)(attr._a_stackaddr - size);
/* Use application-provided stack for TLS only when
if (need < size/8 && need < 2048) {
tsd = stack - __pthread_tsd_size;
stack = tsd - libc.tls_size;
+ memset(stack, 0, need);
} else {
size = ROUND(need);
guard = 0;
}
} else {
- guard = ROUND(DEFAULT_GUARD_SIZE + attr._a_guardsize);
- size = guard + ROUND(DEFAULT_STACK_SIZE + attr._a_stacksize
+ guard = ROUND(attr._a_guardsize);
+ size = guard + ROUND(attr._a_stacksize
+ libc.tls_size + __pthread_tsd_size);
}
if (!tsd) {
if (guard) {
- map = mmap(0, size, PROT_NONE, MAP_PRIVATE|MAP_ANON, -1, 0);
+ map = __mmap(0, size, PROT_NONE, MAP_PRIVATE|MAP_ANON, -1, 0);
if (map == MAP_FAILED) goto fail;
- if (mprotect(map+guard, size-guard, PROT_READ|PROT_WRITE)) {
- munmap(map, size);
+ if (__mprotect(map+guard, size-guard, PROT_READ|PROT_WRITE)
+ && errno != ENOSYS) {
+ __munmap(map, size);
goto fail;
}
} else {
- map = mmap(0, size, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANON, -1, 0);
+ map = __mmap(0, size, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANON, -1, 0);
if (map == MAP_FAILED) goto fail;
}
tsd = map + size - __pthread_tsd_size;
new->map_size = size;
new->stack = stack;
new->stack_size = stack - stack_limit;
- new->pid = self->pid;
- new->errno_ptr = &new->errno_val;
new->start = entry;
new->start_arg = arg;
new->self = new;
new->tsd = (void *)tsd;
+ new->locale = &libc.global_locale;
if (attr._a_detach) {
new->detached = 1;
- flags -= 0x200000;
+ flags -= CLONE_CHILD_CLEARTID;
}
if (attr._a_sched) {
do_sched = new->startlock[0] = 1;
- __syscall(SYS_rt_sigprocmask, SIG_BLOCK,
- SIGALL_SET, self->sigmask, _NSIG/8);
+ __block_app_sigs(new->sigmask);
}
+ new->robust_list.head = &new->robust_list.head;
new->unblock_cancel = self->cancel;
- new->canary = self->canary;
+ new->CANARY = self->CANARY;
a_inc(&libc.threads_minus_1);
- ret = __clone(start, stack, flags, new, &new->tid, TP_ADJ(new), &new->tid);
+ ret = __clone((c11 ? start_c11 : start), stack, flags, new, &new->tid, TP_ADJ(new), &new->tid);
__release_ptc();
if (do_sched) {
- __syscall(SYS_rt_sigprocmask, SIG_SETMASK,
- new->sigmask, 0, _NSIG/8);
+ __restore_sigs(new->sigmask);
}
if (ret < 0) {
a_dec(&libc.threads_minus_1);
- if (map) munmap(map, size);
+ if (map) __munmap(map, size);
return EAGAIN;
}
if (do_sched) {
ret = __syscall(SYS_sched_setscheduler, new->tid,
attr._a_policy, &attr._a_prio);
- a_store(new->startlock, ret<0 ? 2 : 0);
+ a_store(new->startlock, ret<0 ? 2 : 3);
__wake(new->startlock, 1, 1);
if (ret < 0) return -ret;
}
__release_ptc();
return EAGAIN;
}
+
+weak_alias(__pthread_exit, pthread_exit);
+weak_alias(__pthread_create, pthread_create);
projects / oweals / musl.git / blobdiff