TLS (GNU/C11 thread-local storage) support for static-linked programs

[musl] / src / thread / pthread_create.c

diff --git a/src/thread/pthread_create.c b/src/thread/pthread_create.c
index 917be54..f53fc1b 100644 (file)
--- a/src/thread/pthread_create.c
+++ b/src/thread/pthread_create.c
@@ -8,7 +8,7 @@ weak_alias(dummy_0, __synccall_lock);
 weak_alias(dummy_0, __synccall_unlock);
 weak_alias(dummy_0, __pthread_tsd_run_dtors);
 
-void pthread_exit(void *result)
+_Noreturn void pthread_exit(void *result)
 {
        pthread_t self = pthread_self();
        int n;
@@ -24,33 +24,36 @@ void pthread_exit(void *result)
 
        __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;
-       a_store(&self->killlock, 0);
+       __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);
 
        if (self->detached && self->map_base) {
-               __syscall(SYS_rt_sigprocmask, SIG_BLOCK, (uint64_t[]){-1},0,8);
+               if (self->detached == 2)
+                       __syscall(SYS_set_tid_address, 0);
+               __syscall(SYS_rt_sigprocmask, SIG_BLOCK,
+                       SIGALL_SET, 0, __SYSCALL_SSLEN);
                __unmapself(self->map_base, self->map_size);
        }
 
-       __syscall(SYS_exit, 0);
+       for (;;) __syscall(SYS_exit, 0);
 }
 
-void __do_cleanup_push(struct __ptcb *cb, void (*f)(void *), void *x)
+void __do_cleanup_push(struct __ptcb *cb)
 {
        struct pthread *self = pthread_self();
        cb->__next = self->cancelbuf;
        self->cancelbuf = cb;
 }
 
-void __do_cleanup_pop(struct __ptcb *cb, int run)
+void __do_cleanup_pop(struct __ptcb *cb)
 {
        __pthread_self()->cancelbuf = cb->__next;
 }
@@ -59,7 +62,8 @@ static int start(void *p)
 {
        pthread_t self = p;
        if (self->unblock_cancel)
-               __syscall(SYS_rt_sigprocmask, SIG_UNBLOCK, SIGPT_SET, 0, 8);
+               __syscall(SYS_rt_sigprocmask, SIG_UNBLOCK,
+                       SIGPT_SET, 0, __SYSCALL_SSLEN);
        pthread_exit(self->start(self->start_arg));
        return 0;
 }
@@ -80,13 +84,18 @@ static void init_file_lock(FILE *f)
        if (f && f->lock<0) f->lock = 0;
 }
 
-int pthread_create(pthread_t *res, const pthread_attr_t *attr, void *(*entry)(void *), void *arg)
+void *__copy_tls(unsigned char *, size_t);
+
+int pthread_create(pthread_t *restrict res, const pthread_attr_t *restrict attr, void *(*entry)(void *), void *restrict arg)
 {
        int ret;
        size_t size = DEFAULT_STACK_SIZE + DEFAULT_GUARD_SIZE;
        size_t guard = DEFAULT_GUARD_SIZE;
        struct pthread *self = pthread_self(), *new;
        unsigned char *map, *stack, *tsd;
+       unsigned flags = 0x7d8f00;
+       size_t tls_cnt = libc.tls_cnt;
+       size_t tls_size = libc.tls_size;
 
        if (!self) return ENOSYS;
        if (!libc.threaded) {
@@ -95,21 +104,33 @@ int pthread_create(pthread_t *res, const pthread_attr_t *attr, void *(*entry)(vo
                init_file_lock(__stdin_used);
                init_file_lock(__stdout_used);
                init_file_lock(__stderr_used);
-               __syscall(SYS_rt_sigprocmask, SIG_UNBLOCK, SIGPT_SET, 0, 8);
                libc.threaded = 1;
        }
 
-       if (attr) {
-               guard = ROUND(attr->_a_guardsize + DEFAULT_GUARD_SIZE);
-               size = guard + ROUND(attr->_a_stacksize + DEFAULT_STACK_SIZE);
+       if (attr && attr->_a_stackaddr) {
+               map = 0;
+               tsd = (void *)(attr->_a_stackaddr-__pthread_tsd_size & -16);
+       } else {
+               if (attr) {
+                       guard = ROUND(attr->_a_guardsize + DEFAULT_GUARD_SIZE);
+                       size = guard + ROUND(attr->_a_stacksize
+                               + DEFAULT_STACK_SIZE + tls_size);
+               }
+               size += __pthread_tsd_size;
+               if (guard) {
+                       map = mmap(0, size, PROT_NONE, MAP_PRIVATE|MAP_ANON, -1, 0);
+                       if (map == MAP_FAILED) return EAGAIN;
+                       if (mprotect(map+guard, size-guard, PROT_READ|PROT_WRITE)) {
+                               munmap(map, size);
+                               return EAGAIN;
+                       }
+               } else {
+                       map = mmap(0, size, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANON, -1, 0);
+                       if (map == MAP_FAILED) return EAGAIN;
+               }
+               tsd = map + size - __pthread_tsd_size;
        }
-       size += __pthread_tsd_size;
-       map = mmap(0, size, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANON, -1, 0);
-       if (map == MAP_FAILED) return EAGAIN;
-       if (guard) mprotect(map, guard, PROT_NONE);
-
-       tsd = map + size - __pthread_tsd_size;
-       new = (void *)(tsd - sizeof *new - PAGE_SIZE%sizeof *new);
+       new = __copy_tls(tsd - tls_size, tls_cnt);
        new->map_base = map;
        new->map_size = size;
        new->pid = self->pid;
@@ -118,7 +139,10 @@ int pthread_create(pthread_t *res, const pthread_attr_t *attr, void *(*entry)(vo
        new->start_arg = arg;
        new->self = new;
        new->tsd = (void *)tsd;
-       if (attr) new->detached = attr->_a_detach;
+       if (attr && attr->_a_detach) {
+               new->detached = 1;
+               flags -= 0x200000;
+       }
        new->unblock_cancel = self->cancel;
        new->canary = self->canary ^ (uintptr_t)&new;
        stack = (void *)new;
@@ -126,7 +150,7 @@ int pthread_create(pthread_t *res, const pthread_attr_t *attr, void *(*entry)(vo
        __synccall_lock();
 
        a_inc(&libc.threads_minus_1);
-       ret = __clone(start, stack, 0x7d8f00, new, &new->tid, new, &new->tid);
+       ret = __clone(start, stack, flags, new, &new->tid, new, &new->tid);
 
        __synccall_unlock();