#include "pthread_impl.h"
+#include "stdio_impl.h"
-void __pthread_unwind_next(struct __ptcb *cb)
+static void dummy_0()
{
- int i, j, not_finished;
- pthread_t self;
-
- if (cb->__next) longjmp((void *)cb->__next->__jb, 1);
-
- self = pthread_self();
- if (self->cancel) self->result = PTHREAD_CANCELLED;
-
- LOCK(&self->exitlock);
-
- not_finished = self->tsd_used;
- for (j=0; not_finished && j<PTHREAD_DESTRUCTOR_ITERATIONS; j++) {
- not_finished = 0;
- for (i=0; i<PTHREAD_KEYS_MAX; i++) {
- if (self->tsd[i] && libc.tsd_keys[i]) {
- void *tmp = self->tsd[i];
- self->tsd[i] = 0;
- libc.tsd_keys[i](tmp);
- not_finished = 1;
- }
- }
+}
+weak_alias(dummy_0, __synccall_lock);
+weak_alias(dummy_0, __synccall_unlock);
+weak_alias(dummy_0, __pthread_tsd_run_dtors);
+
+void __pthread_do_unwind(struct __ptcb *cb)
+{
+ pthread_t self = pthread_self();
+ int n;
+
+ if (cb->__next) {
+ self->cancelbuf = cb->__next->__next;
+ longjmp((void *)cb->__next->__jb, 1);
}
+ __pthread_tsd_run_dtors();
+
+ __lock(&self->exitlock);
+
/* Mark this thread dead before decrementing count */
+ __lock(&self->killlock);
self->dead = 1;
+ a_store(&self->killlock, 0);
- if (!a_fetch_add(&libc.threads_minus_1, -1))
- exit(0);
+ 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) {
- syscall4(__NR_rt_sigprocmask, SIG_BLOCK, (long)(uint64_t[1]){-1},0,8);
+ __syscall(SYS_rt_sigprocmask, SIG_BLOCK, (uint64_t[]){-1},0,8);
__unmapself(self->map_base, self->map_size);
}
- __syscall_exit(0);
+ __syscall(SYS_exit, 0);
}
-static void docancel(struct pthread *self)
+void __pthread_do_register(struct __ptcb *cb)
{
- struct __ptcb cb = { .__next = self->cancelbuf };
- __pthread_unwind_next(&cb);
-}
-
-static void cancel_handler(int sig, siginfo_t *si, void *ctx)
-{
- struct pthread *self = __pthread_self();
- if (si->si_code > 0 || si->si_pid != self->pid) return;
- self->cancel = 1;
- if (self->canceldisable || (!self->cancelasync && !self->cancelpoint))
- return;
- docancel(self);
-}
-
-static void cancelpt(int x)
-{
- struct pthread *self = __pthread_self();
- if (self->canceldisable) return;
- self->cancelpoint = x;
- if (self->cancel) docancel(self);
-}
-
-/* "rsyscall" is a mechanism by which a thread can synchronously force all
- * other threads to perform an arbitrary syscall. It is necessary to work
- * around the non-conformant implementation of setuid() et al on Linux,
- * which affect only the calling thread and not the whole process. This
- * implementation performs some tricks with signal delivery to work around
- * the fact that it does not keep any list of threads in userspace. */
-
-static struct {
- volatile int lock, hold, blocks, cnt;
- unsigned long arg[6];
- int nr;
- int err;
-} rs;
-
-static void rsyscall_handler(int sig, siginfo_t *si, void *ctx)
-{
- struct pthread *self = __pthread_self();
-
- if (si->si_code > 0 || si->si_pid != self->pid ||
- rs.cnt == libc.threads_minus_1) return;
-
- /* Threads which have already decremented themselves from the
- * thread count must not increment rs.cnt or otherwise act. */
- if (self->dead) {
- __wait(&rs.hold, 0, 1, 1);
- return;
- }
-
- if (__syscall(rs.nr, rs.arg[0], rs.arg[1], rs.arg[2],
- rs.arg[3], rs.arg[4], rs.arg[5]) < 0 && !rs.err) rs.err=errno;
-
- a_inc(&rs.cnt);
- __wake(&rs.cnt, 1, 1);
- while(rs.hold)
- __wait(&rs.hold, 0, 1, 1);
- a_dec(&rs.cnt);
- if (!rs.cnt) __wake(&rs.cnt, 1, 1);
+ struct pthread *self = pthread_self();
+ cb->__next = self->cancelbuf;
+ self->cancelbuf = cb;
}
-static int rsyscall(int nr, long a, long b, long c, long d, long e, long f)
+void __pthread_do_unregister(struct __ptcb *cb)
{
- int i, ret;
- sigset_t set = { 0 };
struct pthread *self = __pthread_self();
- sigaddset(&set, SIGSYSCALL);
-
- LOCK(&rs.lock);
- while ((i=rs.blocks))
- __wait(&rs.blocks, 0, i, 1);
-
- __libc_sigprocmask(SIG_BLOCK, &set, 0);
-
- rs.nr = nr;
- rs.arg[0] = a; rs.arg[1] = b;
- rs.arg[2] = c; rs.arg[3] = d;
- rs.arg[4] = d; rs.arg[5] = f;
- rs.hold = 1;
- rs.err = 0;
- rs.cnt = 0;
-
- /* Dispatch signals until all threads respond */
- for (i=libc.threads_minus_1; i; i--)
- sigqueue(self->pid, SIGSYSCALL, (union sigval){0});
- while ((i=rs.cnt) < libc.threads_minus_1) {
- sigqueue(self->pid, SIGSYSCALL, (union sigval){0});
- __wait(&rs.cnt, 0, i, 1);
- }
-
- /* Handle any lingering signals with no-op */
- __libc_sigprocmask(SIG_UNBLOCK, &set, 0);
-
- /* Resume other threads' signal handlers and wait for them */
- rs.hold = 0;
- __wake(&rs.hold, -1, 0);
- while((i=rs.cnt)) __wait(&rs.cnt, 0, i, 1);
-
- if (rs.err) errno = rs.err, ret = -1;
- else ret = __syscall(nr, a, b, c, d, e, f);
-
- UNLOCK(&rs.lock);
- return ret;
+ self->cancelbuf = self->cancelbuf->__next;
}
-static void init_threads()
+static void start(pthread_t self)
{
- struct sigaction sa = { .sa_flags = SA_SIGINFO | SA_RESTART };
- libc.lock = __lock;
- libc.lockfile = __lockfile;
- libc.cancelpt = cancelpt;
- libc.rsyscall = rsyscall;
- sa.sa_sigaction = cancel_handler;
- __libc_sigaction(SIGCANCEL, &sa, 0);
- sigaddset(&sa.sa_mask, SIGSYSCALL);
- sigaddset(&sa.sa_mask, SIGCANCEL);
- sa.sa_sigaction = rsyscall_handler;
- __libc_sigaction(SIGSYSCALL, &sa, 0);
- sigprocmask(SIG_UNBLOCK, &sa.sa_mask, 0);
-}
-
-static int start(void *p)
-{
- struct pthread *self = p;
+ if (self->unblock_cancel)
+ __syscall(SYS_rt_sigprocmask, SIG_UNBLOCK, SIGPT_SET, 0, 8);
pthread_exit(self->start(self->start_arg));
- return 0;
}
-int __uniclone(void *, int (*)(), void *);
-
#define ROUND(x) (((x)+PAGE_SIZE-1)&-PAGE_SIZE)
/* pthread_key_create.c overrides this */
static const size_t dummy = 0;
weak_alias(dummy, __pthread_tsd_size);
+static FILE *const dummy_file = 0;
+weak_alias(dummy_file, __stdin_used);
+weak_alias(dummy_file, __stdout_used);
+weak_alias(dummy_file, __stderr_used);
+
+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)
{
- static int init;
int ret;
- size_t size, guard;
+ 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;
- static const pthread_attr_t default_attr;
- if (!self) return errno = ENOSYS;
- if (!init && ++init) init_threads();
+ if (!self) return ENOSYS;
+ if (!libc.threaded) {
+ for (FILE *f=libc.ofl_head; f; f=f->next)
+ init_file_lock(f);
+ 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) attr = &default_attr;
- guard = ROUND(attr->_a_guardsize + DEFAULT_GUARD_SIZE);
- size = guard + ROUND(attr->_a_stacksize + DEFAULT_STACK_SIZE);
+ if (attr) {
+ guard = ROUND(attr->_a_guardsize + DEFAULT_GUARD_SIZE);
+ size = guard + ROUND(attr->_a_stacksize + DEFAULT_STACK_SIZE);
+ }
size += __pthread_tsd_size;
map = mmap(0, size, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE|MAP_ANON, -1, 0);
if (!map) return EAGAIN;
new->start_arg = arg;
new->self = new;
new->tsd = (void *)tsd;
- new->detached = attr->_a_detach;
- new->attr = *attr;
+ if (attr) new->detached = attr->_a_detach;
+ new->unblock_cancel = self->cancel;
memcpy(new->tlsdesc, self->tlsdesc, sizeof new->tlsdesc);
new->tlsdesc[1] = (uintptr_t)new;
stack = (void *)((uintptr_t)new-1 & ~(uintptr_t)15);
- /* We must synchronize new thread creation with rsyscall
- * delivery. This looks to be the least expensive way: */
- a_inc(&rs.blocks);
- while (rs.lock) __wait(&rs.lock, 0, 1, 1);
+ __synccall_lock();
a_inc(&libc.threads_minus_1);
ret = __uniclone(stack, start, new);
- a_dec(&rs.blocks);
- if (rs.lock) __wake(&rs.blocks, 1, 1);
+ __synccall_unlock();
if (ret < 0) {
a_dec(&libc.threads_minus_1);
void pthread_exit(void *result)
{
struct pthread *self = pthread_self();
+ struct __ptcb cb = { .__next = self->cancelbuf };
self->result = result;
- docancel(self);
+ __pthread_do_unwind(&cb);
}
projects / musl / blobdiff