rc

commit 43c1019eca5e6d67e239cb38d54cd9c359577827
parent b79e7f2d747a7ad926e15eb1395616a3babb6671
Author: tgoodwin <tgoodwin>
Date:   Tue, 21 Jul 1998 14:27:42 +0000

fix for Linux with glibc2 so system calls are not restarted

Diffstat:
M
acconfig.h
 | 
3
+++
M
configure.ac
 | 
34
+++++++++++++++++++++++++---------
M
signal.c
 | 
27
++++++++++++++++++++-------

3 files changed, 48 insertions(+), 16 deletions(-)
diff --git a/acconfig.h b/acconfig.h
@@ -69,3 +69,6 @@
 
 /* Define to release date. */
 #undef RELDATE
+
+/* Define if you have SA_INTERRUPT (and sigaction()). */
+#undef HAVE_SA_INTERRUPT
diff --git a/configure.ac b/configure.ac
@@ -35,14 +35,6 @@ AC_TYPE_SIZE_T
 AC_TYPE_UID_T
 AC_CHECK_TYPE(ssize_t, long)
 
-dnl Check type of sig_atomic_t.
-AC_CACHE_CHECK(for sig_atomic_t, rc_cv_sig_atomic_t,
-	AC_EGREP_HEADER(sig_atomic_t, signal.h,
-		rc_cv_sig_atomic_t=yes, rc_cv_sig_atomic_t=no))
-case "$rc_cv_sig_atomic_t" in
-no)	AC_DEFINE(sig_atomic_t, int) ;;
-esac
-
 AC_CHECK_FUNCS(getgroups setpgrp setrlimit)
 
 
@@ -133,7 +125,31 @@ main(){
 	;;
 esac
 
-AC_SYS_RESTARTABLE_SYSCALLS
+dnl Check type of sig_atomic_t.
+AC_CACHE_CHECK(for sig_atomic_t, rc_cv_sig_atomic_t,
+	AC_EGREP_HEADER(sig_atomic_t, signal.h,
+		rc_cv_sig_atomic_t=yes, rc_cv_sig_atomic_t=no))
+case "$rc_cv_sig_atomic_t" in
+no)	AC_DEFINE(sig_atomic_t, int) ;;
+esac
+
+dnl We prefer system calls that don't restart.  If we have sigaction() and
+dnl SA_INTERRUPT, we'll use 'em.  Otherwise, we check whether
+dnl good ol' signal() produces interruptible system calls.
+AC_CACHE_CHECK(for sigaction and SA_INTERRUPT, rc_cv_sa_int,
+	AC_TRY_COMPILE([
+#include <signal.h>
+	], [
+struct sigaction foo;
+foo.sa_flags = SA_INTERRUPT;
+sigaction(SIGINT, 0, 0);
+	], rc_cv_sa_int=yes, rc_cv_sa_int=no
+	)
+)
+case "$rc_cv_sa_int" in
+yes)	AC_DEFINE(HAVE_SA_INTERRUPT) ;;
+no) AC_SYS_RESTARTABLE_SYSCALLS ;;
+esac
 AM_CONDITIONAL(AMC_RESTART, test "$ac_cv_sys_restartable_syscalls" = yes)
 
 dnl Do we have SysV SIGCLD semantics?  In other words, if we set the
diff --git a/signal.c b/signal.c
@@ -7,6 +7,19 @@
 #include "sigmsgs.h"
 #include "jbwrap.h"
 
+#if HAVE_SA_INTERRUPT
+static void (*sys_signal(int signum, void (*handler)(int)))(int) {
+	struct sigaction new, old;
+
+	new.sa_handler = handler;
+	new.sa_flags = SA_INTERRUPT;
+	sigaction(signum, &new, &old);
+	return old.sa_handler;
+}
+#else
+#define sys_signal signal
+#endif
+
 void (*sighandlers[NUMOFSIGNALS])(int);
 
 static volatile sig_atomic_t sigcount, caught[NUMOFSIGNALS];
@@ -16,7 +29,7 @@ extern void catcher(int s) {
 		sigcount++;
 		caught[s] = 1;
 	}
-	signal(s, catcher);
+	sys_signal(s, catcher);
 
 #if READLINE
 	if (rl_active)
@@ -59,11 +72,11 @@ extern void (*rc_signal(int s, void (*h)(int)))(int) {
 	sigchk();
 	old = sighandlers[s];
 	if (h == SIG_DFL || h == SIG_IGN) {
-		signal(s, h);
 		sighandlers[s] = h;
+		sys_signal(s, h);
 	} else {
 		sighandlers[s] = h;
-		signal(s, catcher);
+		sys_signal(s, catcher);
 	}
 	return old;
 }
@@ -73,16 +86,16 @@ extern void initsignal() {
 	int i;
 
 	for (i = 1; i < NUMOFSIGNALS; i++) {
-		h = signal(i, SIG_DFL);
+		h = sys_signal(i, SIG_DFL);
 		if (h != SIG_DFL && h != SIG_ERR)
-			signal(i, h);
+			sys_signal(i, h);
 		sighandlers[i] = h;
 	}
 
 #if HAVE_SYSV_SIGCLD
 	/* Ensure that SIGCLD is not SIG_IGN.  Solaris's rshd does this.  :-( */
-	h = signal(SIGCLD, SIG_DFL);
+	h = sys_signal(SIGCLD, SIG_DFL);
 	if (h != SIG_IGN && h != SIG_ERR)
-		signal(SIGCLD, h);
+		sys_signal(SIGCLD, h);
 #endif
 }