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.

1 files changed, 3 insertions, 5 deletions

diff --git a/src/signal/raise.c b/src/signal/raise.c
index 9948f418..71e0505b 100644
--- a/src/signal/raise.c
+++ b/src/signal/raise.c
@@ -1,18 +1,16 @@
 #include <signal.h>
 #include <errno.h>
+#include <stdint.h>
 #include "syscall.h"
 
-int __sigprocmask(int, const sigset_t *, sigset_t *);
-
 int raise(int sig)
 {
 	int pid, tid, ret;
 	sigset_t set;
-	sigfillset(&set);
-	__sigprocmask(SIG_BLOCK, &set, &set);
+	__syscall(SYS_rt_sigprocmask, SIG_BLOCK, (uint64_t[]){-1}, &set, 8);
 	tid = syscall(SYS_gettid);
 	pid = syscall(SYS_getpid);
 	ret = syscall(SYS_tgkill, pid, tid, sig);
-	__sigprocmask(SIG_SETMASK, &set, 0);
+	__syscall(SYS_rt_sigprocmask, SIG_SETMASK, &set, 0, 8);
 	return ret;
 }