add new masked cancellation mode

[musl] / src / thread / pthread_cancel.c

diff --git a/src/thread/pthread_cancel.c b/src/thread/pthread_cancel.c
index e3d291e..1b71aa4 100644 (file)
--- a/src/thread/pthread_cancel.c
+++ b/src/thread/pthread_cancel.c
@@ -1,14 +1,22 @@
 #include "pthread_impl.h"
 #include "syscall.h"
+#include "libc.h"
 
-void __cancel()
+long __cancel()
 {
        pthread_t self = __pthread_self();
-       self->canceldisable = 1;
-       self->cancelasync = 0;
-       pthread_exit(PTHREAD_CANCELED);
+       if (self->canceldisable == PTHREAD_CANCEL_ENABLE || self->cancelasync)
+               pthread_exit(PTHREAD_CANCELED);
+       self->canceldisable = PTHREAD_CANCEL_DISABLE;
+       return -ECANCELED;
 }
 
+/* If __syscall_cp_asm has adjusted the stack pointer, it must provide a
+ * definition of __cp_cancel to undo those adjustments and call __cancel.
+ * Otherwise, __cancel provides a definition for __cp_cancel. */
+
+weak_alias(__cancel, __cp_cancel);
+
 long __syscall_cp_asm(volatile void *, syscall_arg_t,
                       syscall_arg_t, syscall_arg_t, syscall_arg_t,
                       syscall_arg_t, syscall_arg_t, syscall_arg_t);
@@ -19,13 +27,16 @@ long __syscall_cp_c(syscall_arg_t nr,
 {
        pthread_t self;
        long r;
+       int st;
 
-       if (!libc.has_thread_pointer || (self = __pthread_self())->canceldisable)
+       if (!libc.has_thread_pointer || (st=(self=__pthread_self())->canceldisable)
+           && (st==PTHREAD_CANCEL_DISABLE || nr==SYS_close))
                return __syscall(nr, u, v, w, x, y, z);
 
        r = __syscall_cp_asm(&self->cancel, nr, u, v, w, x, y, z);
-       if (r==-EINTR && nr!=SYS_close && self->cancel && !self->canceldisable)
-               __cancel();
+       if (r==-EINTR && nr!=SYS_close && self->cancel &&
+           self->canceldisable != PTHREAD_CANCEL_DISABLE)
+               r = __cancel();
        return r;
 }
 
@@ -42,14 +53,14 @@ static void cancel_handler(int sig, siginfo_t *si, void *ctx)
        const char *ip = ((char **)&uc->uc_mcontext)[CANCEL_REG_IP];
        extern const char __cp_begin[1], __cp_end[1];
 
-       if (!self->cancel || self->canceldisable) return;
+       a_barrier();
+       if (!self->cancel || self->canceldisable == PTHREAD_CANCEL_DISABLE) return;
 
        _sigaddset(&uc->uc_sigmask, SIGCANCEL);
 
        if (self->cancelasync || ip >= __cp_begin && ip < __cp_end) {
-               self->canceldisable = 1;
-               pthread_sigmask(SIG_SETMASK, &uc->uc_sigmask, 0);
-               __cancel();
+               ((char **)&uc->uc_mcontext)[CANCEL_REG_IP] = (char *)__cp_cancel;
+               return;
        }
 
        __syscall(SYS_tkill, self->tid, SIGCANCEL);