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 52b48d6..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;
@@ -43,7 +43,7 @@ void pthread_exit(void *result)
                __unmapself(self->map_base, self->map_size);
        }
 
-       __syscall(SYS_exit, 0);
+       for (;;) __syscall(SYS_exit, 0);
 }
 
 void __do_cleanup_push(struct __ptcb *cb)
@@ -84,7 +84,9 @@ 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;
@@ -92,6 +94,8 @@ int pthread_create(pthread_t *res, const pthread_attr_t *attr, void *(*entry)(vo
        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) {
@@ -109,15 +113,24 @@ int pthread_create(pthread_t *res, const pthread_attr_t *attr, void *(*entry)(vo
        } else {
                if (attr) {
                        guard = ROUND(attr->_a_guardsize + DEFAULT_GUARD_SIZE);
-                       size = guard + ROUND(attr->_a_stacksize + DEFAULT_STACK_SIZE);
+                       size = guard + ROUND(attr->_a_stacksize
+                               + DEFAULT_STACK_SIZE + tls_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);
+               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;
        }
-       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;