2 files changed, 67 insertions, 0 deletions
diff --git a/include/unistd.h b/include/unistd.h
index a64d99b7..35cfda8c 100644
--- a/include/unistd.h
+++ b/include/unistd.h
@@ -147,6 +147,7 @@ int getdtablesize(void);
 #ifdef _GNU_SOURCE
 int brk(void *);
 void *sbrk(intptr_t);
+pid_t forkall(void);
 pid_t vfork(void);
 int vhangup(void);
 int chroot(const char *);
diff --git a/src/thread/forkall.c b/src/thread/forkall.c
new file mode 100644
index 00000000..403818ec
--- /dev/null
+++ b/src/thread/forkall.c
@@ -0,0 +1,66 @@
+#include "pthread_impl.h"
+#include <setjmp.h>
+
+struct thread {
+	struct thread *next;
+	pthread_t td;
+	jmp_buf jb;
+	void *tmp, *stack;
+};
+
+struct ctx {
+	struct thread *list;
+	pthread_t caller;
+	pid_t pid;
+	size_t cnt;
+	pthread_barrier_t barrier;
+};
+
+static void restart_thread(pthread_t self)
+{
+	struct thread *t = self->start_arg;
+	self->start_arg = t->tmp;
+	self->pid = getpid();
+	longjmp(t->jb, 1);
+}
+
+static void do_forkall(void *p)
+{
+	struct ctx *c = p, *volatile cv = c;
+	char tmpstack[2048];
+	struct thread *tp, t = {
+		.td = __pthread_self(),
+		.next = c->list,
+		.stack = tmpstack+1024
+	};
+
+	if (t.td != c->caller) {
+		c->cnt++;
+		t.tmp = t.td->start_arg;
+		t.td->start_arg = &t;
+		if (setjmp(t.jb)) {
+			c = cv;
+			if (c->pid) return;
+			pthread_barrier_wait(&c->barrier);
+			return;
+		}
+		c->list = &t;
+		__synccall_wait();
+		return;
+	}
+	c->pid = syscall(SYS_fork);
+	if (c->pid) return;
+
+	pthread_barrier_init(&c->barrier, 0, c->cnt);
+	for (tp=c->list; tp; tp=tp->next)
+		if (__uniclone(tp->stack, restart_thread, tp->td) < 0)
+			_exit(127);
+	pthread_barrier_wait(&c->barrier);
+}
+
+pid_t forkall()
+{
+	struct ctx c = { .caller = pthread_self() };
+	__synccall(do_forkall, &c);
+	return c.pid;
+}