Portability: don't call sigaction() for SIGKILL or SIGCONT; don't

  hand a garbage signal mask to sigaction() (thanks Jeremy
  Fitzhardinge).  Also, remove use of SA_INTERRUPT (SUSv3, BSD,
  etc. have SA_RESTART with the inverted meaning).

4 files changed, 26 insertions, 30 deletions

diff --git a/ChangeLog b/ChangeLog
index 954ff12..e3b0484 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -802,3 +802,8 @@ Changes since rc-1.5b2
   Bug: variables that are sometimes exported (i.e. $prompt and
   $version) need to be made exportable if they are inherited from the
   environment.
+
+  Portability: don't call sigaction() for SIGKILL or SIGCONT; don't
+  hand a garbage signal mask to sigaction() (thanks Jeremy
+  Fitzhardinge).  Also, remove use of SA_INTERRUPT (SUSv3, BSD,
+  etc. have SA_RESTART with the inverted meaning).
diff --git a/acinclude.m4 b/acinclude.m4
index 7fbc6aa..0cf3307 100644
--- a/acinclude.m4
+++ b/acinclude.m4
@@ -128,21 +128,6 @@ AC_DEFUN(RC_TYPE_SIG_ATOMIC_T, [
 ])
 
 
-dnl Check for sigaction and SA_INTERRUPT
-AC_DEFUN(RC_FUNC_SIGACTION, [
-	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
-		)
-	)
-])
-
-
 dnl Do we have SysV SIGCLD semantics?  In other words, if we set the
 dnl action for SIGCLD to SIG_IGN does wait() always say ECHILD?  Linux,
 dnl of course, is bizarre here.  It basically implements the SysV
diff --git a/configure.ac b/configure.ac
index 9e26d5d..59a58c1 100644
--- a/configure.ac
+++ b/configure.ac
@@ -40,7 +40,16 @@ AC_TYPE_SIZE_T
 AC_TYPE_UID_T
 AC_CHECK_TYPE(ssize_t, long)
 
-AC_CHECK_FUNCS(getgroups lstat setpgrp setrlimit)
+AC_CHECK_FUNCS(getgroups lstat setpgrp setrlimit sigaction)
+
+dnl We prefer system calls that don't restart.  If we have sigaction()
+dnl we'll use it.  Otherwise, we check whether good ol' signal()
+dnl produces interruptible system calls.
+case "$ac_cv_func_sigaction" in
+no) AC_SYS_RESTARTABLE_SYSCALLS ;;
+esac
+AM_CONDITIONAL(AMC_RESTART, test "$ac_cv_sys_restartable_syscalls" = yes)
+
 RC_FUNC_GETGROUPS
 
 RC_FUNC_SIGSETJMP
@@ -55,16 +64,6 @@ RC_TYPE_RLIM_T
 
 RC_TYPE_SIG_ATOMIC_T
 
-dnl We prefer system calls that don't restart.  If we have sigaction()
-dnl and SA_INTERRUPT, we'll use 'em.  Otherwise, we check whether good
-dnl ol' signal() produces interruptible system calls.
-RC_FUNC_SIGACTION
-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)
-
 RC_SYS_V_SIGCLD
 
 dnl Does the kernel handle `#! /interpreter'?
diff --git a/signal.c b/signal.c
index de06633..dfdc8d0 100644
--- a/signal.c
+++ b/signal.c
@@ -8,17 +8,18 @@
 #include "sigmsgs.h"
 #include "jbwrap.h"
 
-#if HAVE_SA_INTERRUPT
+#if HAVE_SIGACTION
 static void (*sys_signal(int signum, void (*handler)(int)))(int) {
 	struct sigaction new, old;
 
 	new.sa_handler = handler;
-	new.sa_flags = SA_INTERRUPT;
+	new.sa_flags = 0; /* clear SA_RESTART */
+	sigfillset(&new.sa_mask);
 	sigaction(signum, &new, &old);
 	return old.sa_handler;
 }
 #else
-#define sys_signal signal
+#define sys_signal(sig, func) (signal((sig), (func)))
 #endif
 
 void (*sighandlers[NUMOFSIGNALS])(int);
@@ -40,7 +41,7 @@ extern void catcher(int s) {
 #if HAVE_RESTARTABLE_SYSCALLS
 	if (slow) {
 		siglongjmp(slowbuf.j, s);
-}
+	}
 #endif
 }
 
@@ -96,6 +97,12 @@ extern void initsignal() {
 #endif
 
 	for (i = 1; i < NUMOFSIGNALS; i++) {
+#ifdef SIGKILL
+		if (i == SIGKILL) continue;
+#endif
+#ifdef SIGCONT
+		if (i == SIGCONT) continue;
+#endif
 		h = sys_signal(i, SIG_IGN);
 		if (h != SIG_IGN && h != SIG_ERR)
 			sys_signal(i, h);