X-Git-Url: http://nsz.repo.hu/git/?p=musl;a=blobdiff_plain;f=src%2Fthread%2Fpthread_create.c;h=a6afd1e584873825dd4c3e2793b497fddddff236;hp=52487001484ce8c1edfc08cd7b7027055c4a130d;hb=730bee725a770b543181424b52203dd1634ab5d1;hpb=729cb49f52c825ac44f437e1ff0865d9f0b3626a

diff --git a/src/thread/pthread_create.c b/src/thread/pthread_create.c
index 52487001..a6afd1e5 100644
--- a/src/thread/pthread_create.c
+++ b/src/thread/pthread_create.c
@@ -1,189 +1,49 @@
 #include "pthread_impl.h"
+#include "stdio_impl.h"
 
-static void dummy_1(pthread_t self)
+static void dummy_0()
 {
 }
-weak_alias(dummy_1, __pthread_tsd_run_dtors);
-weak_alias(dummy_1, __sigtimer_handler);
+weak_alias(dummy_0, __synccall_lock);
+weak_alias(dummy_0, __synccall_unlock);
+weak_alias(dummy_0, __pthread_tsd_run_dtors);
 
-#ifdef __pthread_unwind_next
-#undef __pthread_unwind_next
-#define __pthread_unwind_next __pthread_unwind_next_3
-#endif
-
-void __pthread_unwind_next(struct __ptcb *cb)
+void __pthread_do_unwind(struct __ptcb *cb)
 {
-	pthread_t self;
-
-	if (cb->__next) longjmp((void *)cb->__next->__jb, 1);
+	pthread_t self = pthread_self();
+	int n;
 
-	self = pthread_self();
+	if (cb->__next) {
+		self->cancelbuf = cb->__next->__next;
+		longjmp((void *)cb->__next->__jb, 1);
+	}
 
-	LOCK(&self->exitlock);
+	__pthread_tsd_run_dtors();
 
-	__pthread_tsd_run_dtors(self);
+	__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) {
-		syscall(__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(SYS_exit, 0);
-}
-
-static void docancel(struct pthread *self)
-{
-	struct __ptcb cb = { .__next = self->cancelbuf };
-	self->canceldisable = 1;
-	self->cancelasync = 0;
-	__pthread_unwind_next(&cb);
-}
-
-static void cancel_handler(int sig, siginfo_t *si, void *ctx)
-{
-	struct pthread *self = __pthread_self();
-	if (si->si_code == SI_TIMER) __sigtimer_handler(self);
-	if (self->cancel && !self->canceldisable &&
-	    (self->cancelasync || (self->cancelpoint==1 && PC_AT_SYS(ctx))))
-		docancel(self);
-}
-
-static void cancelpt(int x)
-{
-	struct pthread *self = __pthread_self();
-	switch (x) {
-	case 1:
-		self->cancelpoint++;
-	case 0:
-		if (self->cancel && self->cancelpoint==1 && !self->canceldisable)
-			docancel(self);
-		break;
-	case -1:
-		self->cancelpoint--;
-		break;
-	default:
-		self->canceldisable += x;
-	}
-}
-
-/* "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 (!rs.hold || 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) {
-		sigfillset(&((ucontext_t *)ctx)->uc_sigmask);
-		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);
-}
-
-static int rsyscall(int nr, long a, long b, long c, long d, long e, long f)
-{
-	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.err = 0;
-	rs.cnt = 0;
-	rs.hold = 1;
-
-	/* 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;
-}
-
-static void init_threads()
-{
-	struct sigaction sa = { .sa_flags = SA_SIGINFO | SA_RESTART };
-	libc.lock = __lock;
-	libc.lockfile = __lockfile;
-	libc.cancelpt = cancelpt;
-	libc.rsyscall = rsyscall;
-
-	sigfillset(&sa.sa_mask);
-	sa.sa_sigaction = rsyscall_handler;
-	__libc_sigaction(SIGSYSCALL, &sa, 0);
-
-	sigemptyset(&sa.sa_mask);
-	sa.sa_sigaction = cancel_handler;
-	__libc_sigaction(SIGCANCEL, &sa, 0);
-
-	sigaddset(&sa.sa_mask, SIGSYSCALL);
-	sigaddset(&sa.sa_mask, SIGCANCEL);
-	__libc_sigprocmask(SIG_UNBLOCK, &sa.sa_mask, 0);
+	__syscall(SYS_exit, 0);
 }
 
 static int start(void *p)
 {
 	struct pthread *self = p;
-	if (self->unblock_cancel) {
-		sigset_t set;
-		sigemptyset(&set);
-		sigaddset(&set, SIGCANCEL);
-		__libc_sigprocmask(SIG_UNBLOCK, &set, 0);
-	}
+	if (self->unblock_cancel)
+		__syscall(SYS_rt_sigprocmask, SIG_UNBLOCK, SIGPT_SET, 0, 8);
 	pthread_exit(self->start(self->start_arg));
 	return 0;
 }
@@ -196,21 +56,39 @@ int __uniclone(void *, int (*)(), void *);
 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 ENOSYS;
-	if (!init && ++init) init_threads();
+	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;
@@ -226,24 +104,18 @@ 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;
-	new->detached = attr->_a_detach;
-	new->attr = *attr;
+	if (attr) new->detached = attr->_a_detach;
 	new->unblock_cancel = self->cancel;
-	new->result = PTHREAD_CANCELED;
 	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);
@@ -257,6 +129,7 @@ int pthread_create(pthread_t *res, const pthread_attr_t *attr, void *(*entry)(vo
 void pthread_exit(void *result)
 {
 	struct pthread *self = pthread_self();
+	struct __ptcb cb = { .__next = self->cancelbuf };
 	self->result = result;
-	docancel(self);
+	__pthread_unwind_next(&cb);
 }