major improvements to cancellation handling

[musl] / src / thread / pthread_create.c

diff --git a/src/thread/pthread_create.c b/src/thread/pthread_create.c
index 17a47f6..18ee64d 100644 (file)
--- a/src/thread/pthread_create.c
+++ b/src/thread/pthread_create.c
@@ -1,5 +1,10 @@
 #include "pthread_impl.h"
 
+#ifdef __pthread_unwind_next
+#undef __pthread_unwind_next
+#define __pthread_unwind_next __pthread_unwind_next_3
+#endif
+
 void __pthread_unwind_next(struct __ptcb *cb)
 {
        int i, j, not_finished;
@@ -42,25 +47,30 @@ void __pthread_unwind_next(struct __ptcb *cb)
 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 > 0 || si->si_pid != self->pid) return;
-       self->cancel = 1;
-       if (self->canceldisable || (!self->cancelasync && !self->cancelpoint))
+       if (!self->cancel) {
+               if (si->si_code == SI_TIMER && libc.sigtimer)
+                       libc.sigtimer(sig, si, ctx);
                return;
-       docancel(self);
+       }
+       if (self->canceldisable) return;
+       if (self->cancelasync || (self->cancelpoint==1 && PC_AT_SYS(ctx)))
+               docancel(self);
 }
 
 static void cancelpt(int x)
 {
        struct pthread *self = __pthread_self();
        if (self->canceldisable) return;
-       self->cancelpoint = x;
-       if (self->cancel) docancel(self);
+       if ((self->cancelpoint+=x)==1 && x>=0 && self->cancel)
+               docancel(self);
 }
 
 /* "rsyscall" is a mechanism by which a thread can synchronously force all
@@ -165,6 +175,12 @@ static void init_threads()
 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);
+       }
        pthread_exit(self->start(self->start_arg));
        return 0;
 }
@@ -209,6 +225,7 @@ int pthread_create(pthread_t *res, const pthread_attr_t *attr, void *(*entry)(vo
        new->tsd = (void *)tsd;
        new->detached = attr->_a_detach;
        new->attr = *attr;
+       new->unblock_cancel = self->cancel;
        memcpy(new->tlsdesc, self->tlsdesc, sizeof new->tlsdesc);
        new->tlsdesc[1] = (uintptr_t)new;
        stack = (void *)((uintptr_t)new-1 & ~(uintptr_t)15);