1 files changed, 70 insertions, 0 deletions
diff --git a/src/thread/cancel_impl.c b/src/thread/cancel_impl.c
new file mode 100644
index 00000000..5ce545d7
--- /dev/null
+++ b/src/thread/cancel_impl.c
@@ -0,0 +1,70 @@
+#include "pthread_impl.h"
+
+long __syscall_cp_asm(volatile void *, long, long, long, long, long, long, long);
+
+long (__syscall_cp)(long nr, long u, long v, long w, long x, long y, long z)
+{
+	pthread_t self;
+	uintptr_t old_sp, old_ip;
+	long r;
+
+	if (!libc.lock || (self = __pthread_self())->canceldisable)
+		return __syscall(nr, u, v, w, x, y, z);
+
+	old_sp = self->cp_sp;
+	old_ip = self->cp_ip;
+	self->cp_sp = 0;
+	self->cp_ip = 0;
+	r = __syscall_cp_asm(&self->cp_sp, nr, u, v, w, x, y, z);
+	self->cp_sp = old_sp;
+	self->cp_ip = old_ip;
+	if (r == -EINTR && self->cancel) pthread_exit(PTHREAD_CANCELED);
+	return r;
+}
+
+static void cancel_handler(int sig, siginfo_t *si, void *ctx)
+{
+	pthread_t self = __pthread_self();
+	ucontext_t *uc = ctx;
+	uintptr_t sp = ((uintptr_t *)&uc->uc_mcontext)[CANCEL_REG_SP];
+	uintptr_t ip = ((uintptr_t *)&uc->uc_mcontext)[CANCEL_REG_IP];
+
+	if (!self->cancel || self->canceldisable) return;
+
+	if (self->cancelasync) pthread_exit(PTHREAD_CANCELED);
+
+	if (sp != self->cp_sp) {
+		if (!sp) return;
+		sigaddset(&uc->uc_sigmask, SIGCANCEL);
+		__syscall(SYS_tgkill, self->pid, self->tid, SIGCANCEL);
+		return;
+	}
+
+	if (ip <= self->cp_ip) pthread_exit(PTHREAD_CANCELED);
+}
+
+static void testcancel()
+{
+	pthread_t self = __pthread_self();
+	if (self->cancel && !self->canceldisable)
+		pthread_exit(PTHREAD_CANCELED);
+}
+
+static void init_cancellation()
+{
+	struct sigaction sa = {
+		.sa_flags = SA_SIGINFO | SA_RESTART,
+		.sa_sigaction = cancel_handler
+	};
+	sigfillset(&sa.sa_mask);
+	__libc_sigaction(SIGCANCEL, &sa, 0);
+	libc.testcancel = testcancel;
+}
+
+int pthread_cancel(pthread_t t)
+{
+	static pthread_once_t once;
+	pthread_once(&once, init_cancellation);
+	a_store(&t->cancel, 1);
+	return pthread_kill(t, SIGCANCEL);
+}