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authorRich Felker <dalias@aerifal.cx>2011-05-07 23:23:58 -0400
committerRich Felker <dalias@aerifal.cx>2011-05-07 23:23:58 -0400
commit99b8a25e941e54537bf39ca2f265c345f393f112 (patch)
tree758faba1a20af40b5d09221d008eddbc704636fa /src/thread
parent77f15d108ee021d4dfbeebe793661131c4470d4d (diff)
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overhaul implementation-internal signal protections
the new approach relies on the fact that the only ways to create sigset_t objects without invoking UB are to use the sig*set() functions, or from the masks returned by sigprocmask, sigaction, etc. or in the ucontext_t argument to a signal handler. thus, as long as sigfillset and sigaddset avoid adding the "protected" signals, there is no way the application will ever obtain a sigset_t including these bits, and thus no need to add the overhead of checking/clearing them when sigprocmask or sigaction is called. note that the old code actually *failed* to remove the bits from sa_mask when sigaction was called. the new implementations are also significantly smaller, simpler, and faster due to ignoring the useless "GNU HURD signals" 65-1024, which are not used and, if there's any sanity in the world, never will be used.
Diffstat (limited to 'src/thread')
-rw-r--r--src/thread/__rsyscall.c5
-rw-r--r--src/thread/pthread_create.c16
2 files changed, 6 insertions, 15 deletions
diff --git a/src/thread/__rsyscall.c b/src/thread/__rsyscall.c
index 61d41df7..e885d9e7 100644
--- a/src/thread/__rsyscall.c
+++ b/src/thread/__rsyscall.c
@@ -56,8 +56,7 @@ int __rsyscall(int nr, long a, long b, long c, long d, long e, long f)
while ((i=rs.blocks))
__wait(&rs.blocks, 0, i, 1);
- sigfillset(&set);
- __libc_sigprocmask(SIG_BLOCK, &set, &set);
+ __syscall(SYS_rt_sigprocmask, SIG_BLOCK, (uint64_t[]){-1}, &set, 8);
if (!rs.init) {
struct sigaction sa = {
@@ -88,7 +87,7 @@ int __rsyscall(int nr, long a, long b, long c, long d, long e, long f)
}
/* Handle any lingering signals with no-op */
- __libc_sigprocmask(SIG_UNBLOCK, &set, &set);
+ __syscall(SYS_rt_sigprocmask, SIG_SETMASK, &set, &set, 8);
/* Resume other threads' signal handlers and wait for them */
rs.hold = 0;
diff --git a/src/thread/pthread_create.c b/src/thread/pthread_create.c
index 0d2c17bb..6545539b 100644
--- a/src/thread/pthread_create.c
+++ b/src/thread/pthread_create.c
@@ -34,7 +34,7 @@ void __pthread_unwind_next(struct __ptcb *cb)
if (!n) exit(0);
if (self->detached && self->map_base) {
- __syscall(SYS_rt_sigprocmask, SIG_BLOCK, (long)(uint64_t[1]){-1},0,8);
+ __syscall(SYS_rt_sigprocmask, SIG_BLOCK, (uint64_t[]){-1},0,8);
__unmapself(self->map_base, self->map_size);
}
@@ -44,12 +44,8 @@ void __pthread_unwind_next(struct __ptcb *cb)
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);
- }
+ if (self->unblock_cancel)
+ __syscall(SYS_rt_sigprocmask, SIG_UNBLOCK, &SIGPT_SET, 0, 8);
pthread_exit(self->start(self->start_arg));
return 0;
}
@@ -72,11 +68,7 @@ int pthread_create(pthread_t *res, const pthread_attr_t *attr, void *(*entry)(vo
if (!self) return ENOSYS;
if (!libc.threaded) {
- sigset_t set;
- sigemptyset(&set);
- sigaddset(&set, SIGSYSCALL);
- sigaddset(&set, SIGCANCEL);
- __libc_sigprocmask(SIG_UNBLOCK, &set, 0);
+ __syscall(SYS_rt_sigprocmask, SIG_UNBLOCK, &SIGPT_SET, 0, 8);
libc.threaded = 1;
}