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-rw-r--r--src/thread/cancel_impl.c70
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);
+}