From: Rich Felker <dalias@aerifal.cx>
Date: Fri, 26 Apr 2013 23:48:01 +0000 (-0400)
Subject: transition to using functions for internal signal blocking/restoring
X-Git-Tag: v0.9.11~62
X-Git-Url: https://git.librecmc.org/?a=commitdiff_plain;h=2c074b0d6cb2b28c5d1c0ccb2809965f4676efeb;p=oweals%2Fmusl.git

transition to using functions for internal signal blocking/restoring

there are several reasons for this change. one is getting rid of the
repetition of the syscall signature all over the place. another is
sharing the constant masks without costly GOT accesses in PIC.

the main motivation, however, is accurately representing whether we
want to block signals that might be handled by the application, or all
signals.
---

diff --git a/src/internal/pthread_impl.h b/src/internal/pthread_impl.h
index 78b69cde..67b05753 100644
--- a/src/internal/pthread_impl.h
+++ b/src/internal/pthread_impl.h
@@ -115,6 +115,10 @@ void __acquire_ptc();
 void __release_ptc();
 void __inhibit_ptc();
 
+void __block_all_sigs(void *);
+void __block_app_sigs(void *);
+void __restore_sigs(void *);
+
 #define DEFAULT_STACK_SIZE 81920
 #define DEFAULT_GUARD_SIZE PAGE_SIZE
 
diff --git a/src/signal/block.c b/src/signal/block.c
new file mode 100644
index 00000000..d7f61001
--- /dev/null
+++ b/src/signal/block.c
@@ -0,0 +1,44 @@
+#include "pthread_impl.h"
+#include "syscall.h"
+#include <signal.h>
+
+static const unsigned long all_mask[] = {
+#if ULONG_MAX == 0xffffffff && _NSIG == 129
+	-1UL, -1UL, -1UL, -1UL
+#elif ULONG_MAX == 0xffffffff
+	-1UL, -1UL
+#else
+	-1UL
+#endif
+};
+
+static const unsigned long app_mask[] = {
+#if ULONG_MAX == 0xffffffff
+#if _NSIG == 65
+	0x7fffffff, 0xfffffffc
+#else
+	0x7fffffff, 0xfffffffc, -1UL, -1UL
+#endif
+#else
+#if _NSIG == 65
+	0xfffffffc7fffffff
+#else
+	0xfffffffc7fffffff, -1UL
+#endif
+#endif
+};
+
+void __block_all_sigs(void *set)
+{
+	__syscall(SYS_rt_sigprocmask, SIG_BLOCK, &all_mask, set, _NSIG/8);
+}
+
+void __block_app_sigs(void *set)
+{
+	__syscall(SYS_rt_sigprocmask, SIG_BLOCK, &app_mask, set, _NSIG/8);
+}
+
+void __restore_sigs(void *set)
+{
+	__syscall(SYS_rt_sigprocmask, SIG_SETMASK, set, 0, _NSIG/8);
+}
diff --git a/src/signal/raise.c b/src/signal/raise.c
index b24dc741..6fa43bef 100644
--- a/src/signal/raise.c
+++ b/src/signal/raise.c
@@ -8,10 +8,10 @@ int raise(int sig)
 {
 	int pid, tid, ret;
 	sigset_t set;
-	__syscall(SYS_rt_sigprocmask, SIG_BLOCK, SIGALL_SET, &set, _NSIG/8);
+	__block_app_sigs(&set);
 	tid = __syscall(SYS_gettid);
 	pid = __syscall(SYS_getpid);
 	ret = syscall(SYS_tgkill, pid, tid, sig);
-	__syscall(SYS_rt_sigprocmask, SIG_SETMASK, &set, 0, _NSIG/8);
+	__restore_sigs(&set);
 	return ret;
 }
diff --git a/src/signal/siglongjmp.c b/src/signal/siglongjmp.c
index bbdde796..a7bcca24 100644
--- a/src/signal/siglongjmp.c
+++ b/src/signal/siglongjmp.c
@@ -2,10 +2,10 @@
 #include <signal.h>
 #include <stdlib.h>
 #include "syscall.h"
+#include "pthread_impl.h"
 
 _Noreturn void siglongjmp(sigjmp_buf buf, int ret)
 {
-	if (buf->__fl) __syscall(SYS_rt_sigprocmask, SIG_SETMASK,
-		buf->__ss, 0, _NSIG/8);
+	if (buf->__fl) __restore_sigs(buf->__ss);
 	longjmp(buf->__jb, ret);
 }
diff --git a/src/thread/pthread_create.c b/src/thread/pthread_create.c
index 6e49acdc..6c841be7 100644
--- a/src/thread/pthread_create.c
+++ b/src/thread/pthread_create.c
@@ -35,7 +35,7 @@ _Noreturn void pthread_exit(void *result)
 	 * This is important to ensure that dynamically allocated TLS
 	 * is not under-allocated/over-committed, and possibly for other
 	 * reasons as well. */
-	__syscall(SYS_rt_sigprocmask, SIG_BLOCK, SIGALL_SET, &set, _NSIG/8);
+	__block_all_sigs(&set);
 
 	/* Wait to unlock the kill lock, which governs functions like
 	 * pthread_kill which target a thread id, until signals have
@@ -51,7 +51,7 @@ _Noreturn void pthread_exit(void *result)
 	 * stdio cleanup code a consistent state. */
 	if (a_fetch_add(&libc.threads_minus_1, -1)==0) {
 		libc.threads_minus_1 = 0;
-		__syscall(SYS_rt_sigprocmask, SIG_SETMASK, &set, 0, _NSIG/8);
+		__restore_sigs(&set);
 		exit(0);
 	}
 
@@ -94,8 +94,7 @@ static int start(void *p)
 			self->detached = 2;
 			pthread_exit(0);
 		}
-		__syscall(SYS_rt_sigprocmask, SIG_SETMASK,
-			self->sigmask, 0, _NSIG/8);
+		__restore_sigs(self->sigmask);
 	}
 	if (self->unblock_cancel)
 		__syscall(SYS_rt_sigprocmask, SIG_UNBLOCK,
@@ -202,8 +201,7 @@ int pthread_create(pthread_t *restrict res, const pthread_attr_t *restrict attrp
 	}
 	if (attr._a_sched) {
 		do_sched = new->startlock[0] = 1;
-		__syscall(SYS_rt_sigprocmask, SIG_BLOCK,
-			SIGALL_SET, new->sigmask, _NSIG/8);
+		__block_app_sigs(new->sigmask);
 	}
 	new->unblock_cancel = self->cancel;
 	new->canary = self->canary;
@@ -214,8 +212,7 @@ int pthread_create(pthread_t *restrict res, const pthread_attr_t *restrict attrp
 	__release_ptc();
 
 	if (do_sched) {
-		__syscall(SYS_rt_sigprocmask, SIG_SETMASK,
-			new->sigmask, 0, _NSIG/8);
+		__restore_sigs(new->sigmask);
 	}
 
 	if (ret < 0) {