major improvements to cancellation handling

- there is no longer any risk of spoofing cancellation requests, since
  the cancel flag is set in pthread_cancel rather than in the signal
  handler.

- cancellation signal is no longer unblocked when running the
  cancellation handlers. instead, pthread_create will cause any new
  threads created from a cancellation handler to unblock their own
  cancellation signal.

- various tweaks in preparation for POSIX timer support.

diff --git a/src/internal/libc.h b/src/internal/libc.h
index bbbb3a4..c83fcaf 100644 (file)
--- a/src/internal/libc.h
+++ b/src/internal/libc.h
@@ -18,6 +18,7 @@ struct __libc {
        FILE *ofl_head;
        int ofl_lock;
        void (*lockfile)(FILE *);
        FILE *ofl_head;
        int ofl_lock;
        void (*lockfile)(FILE *);

+       void (*sigtimer)();

 };
 
 
 };
 
 

diff --git a/src/internal/pthread_impl.h b/src/internal/pthread_impl.h
index 615b963..f2d0ae8 100644 (file)
--- a/src/internal/pthread_impl.h
+++ b/src/internal/pthread_impl.h
@@ -41,10 +41,14 @@ struct pthread {
                long off;
                void *pending;
        } robust_list;
                long off;
                void *pending;
        } robust_list;

+       int unblock_cancel;

 };
 
 struct __timer {
 };
 
 struct __timer {

-       struct sigevent sev;
+       int timerid;
+       union sigval val;
+       void (*notify)(union sigval);
+       pthread_t thread;

 };
 
 #define __SU (sizeof(size_t)/sizeof(int))
 };
 
 #define __SU (sizeof(size_t)/sizeof(int))


@@ -73,7 +77,6 @@ struct __timer {
 
 #define SIGCANCEL 32
 #define SIGSYSCALL 33
 
 #define SIGCANCEL 32
 #define SIGSYSCALL 33

-#define SIGTIMER  32 /* ?? */

 
 int __set_thread_area(void *);
 int __libc_sigaction(int, const struct sigaction *, struct sigaction *);
 
 int __set_thread_area(void *);
 int __libc_sigaction(int, const struct sigaction *, struct sigaction *);

diff --git a/src/thread/pthread_cancel.c b/src/thread/pthread_cancel.c
index 9f7829e..1ff00ad 100644 (file)
--- a/src/thread/pthread_cancel.c
+++ b/src/thread/pthread_cancel.c
@@ -2,5 +2,6 @@
 
 int pthread_cancel(pthread_t t)
 {
 
 int pthread_cancel(pthread_t t)
 {

+       t->cancel = 1;

        return pthread_kill(t, SIGCANCEL);
 }
        return pthread_kill(t, SIGCANCEL);
 }

diff --git a/src/thread/pthread_create.c b/src/thread/pthread_create.c
index 9f22b4c..18ee64d 100644 (file)
--- a/src/thread/pthread_create.c
+++ b/src/thread/pthread_create.c
@@ -47,20 +47,19 @@ void __pthread_unwind_next(struct __ptcb *cb)
 static void docancel(struct pthread *self)
 {
        struct __ptcb cb = { .__next = self->cancelbuf };
 static void docancel(struct pthread *self)
 {
        struct __ptcb cb = { .__next = self->cancelbuf };

-       sigset_t set;

        self->canceldisable = 1;
        self->cancelasync = 0;
        self->canceldisable = 1;
        self->cancelasync = 0;

-       sigemptyset(&set);
-       sigaddset(&set, SIGCANCEL);
-       __libc_sigprocmask(SIG_UNBLOCK, &set, 0);

        __pthread_unwind_next(&cb);
 }
 
 static void cancel_handler(int sig, siginfo_t *si, void *ctx)
 {
        struct pthread *self = __pthread_self();
        __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->cancel) {
+               if (si->si_code == SI_TIMER && libc.sigtimer)
+                       libc.sigtimer(sig, si, ctx);
+               return;
+       }

        if (self->canceldisable) return;
        if (self->cancelasync || (self->cancelpoint==1 && PC_AT_SYS(ctx)))
                docancel(self);
        if (self->canceldisable) return;
        if (self->cancelasync || (self->cancelpoint==1 && PC_AT_SYS(ctx)))
                docancel(self);


@@ -176,6 +175,12 @@ static void init_threads()
 static int start(void *p)
 {
        struct pthread *self = p;
 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;
 }
        pthread_exit(self->start(self->start_arg));
        return 0;
 }


@@ -220,6 +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->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);
        memcpy(new->tlsdesc, self->tlsdesc, sizeof new->tlsdesc);
        new->tlsdesc[1] = (uintptr_t)new;
        stack = (void *)((uintptr_t)new-1 & ~(uintptr_t)15);