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authorRich Felker <dalias@aerifal.cx>2011-03-29 12:58:22 -0400
committerRich Felker <dalias@aerifal.cx>2011-03-29 12:58:22 -0400
commitbf619d82c82052741323aa63c107fbd346c8aaba (patch)
tree11f97d73195bb633df6c6e679ab65a7f8f0fd477 /src
parent70c31c7bd779400d2eb56dcb4075bb37227081db (diff)
downloadmusl-bf619d82c82052741323aa63c107fbd346c8aaba.tar.gz
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.
Diffstat (limited to 'src')
-rw-r--r--src/internal/libc.h1
-rw-r--r--src/internal/pthread_impl.h7
-rw-r--r--src/thread/pthread_cancel.c1
-rw-r--r--src/thread/pthread_create.c18
4 files changed, 19 insertions, 8 deletions
diff --git a/src/internal/libc.h b/src/internal/libc.h
index bbbb3a4c..c83fcafe 100644
--- 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 *);
+ void (*sigtimer)();
};
diff --git a/src/internal/pthread_impl.h b/src/internal/pthread_impl.h
index 615b963a..f2d0ae8c 100644
--- a/src/internal/pthread_impl.h
+++ b/src/internal/pthread_impl.h
@@ -41,10 +41,14 @@ struct pthread {
long off;
void *pending;
} robust_list;
+ int unblock_cancel;
};
struct __timer {
- struct sigevent sev;
+ int timerid;
+ union sigval val;
+ void (*notify)(union sigval);
+ pthread_t thread;
};
#define __SU (sizeof(size_t)/sizeof(int))
@@ -73,7 +77,6 @@ struct __timer {
#define SIGCANCEL 32
#define SIGSYSCALL 33
-#define SIGTIMER 32 /* ?? */
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 9f7829e6..1ff00ad3 100644
--- a/src/thread/pthread_cancel.c
+++ b/src/thread/pthread_cancel.c
@@ -2,5 +2,6 @@
int pthread_cancel(pthread_t t)
{
+ t->cancel = 1;
return pthread_kill(t, SIGCANCEL);
}
diff --git a/src/thread/pthread_create.c b/src/thread/pthread_create.c
index 9f22b4cf..18ee64d6 100644
--- 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 };
- sigset_t set;
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();
- 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);
@@ -176,6 +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;
}
@@ -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->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);