In io.c:wait_any, use sigprocmask if available.

5 files changed, 39 insertions, 3 deletions

diff --git a/ChangeLog b/ChangeLog
index 8fc992d3..9bdbf836 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2013-07-07         Andrew J. Schorr     <aschorr@telemetry-investments.com>
+
+	* configure.ac (AC_CHECK_FUNCS): Check for sigprocmask.
+	* io.c (wait_any): If sigprocmask is available, block signals instead
+	of ignoring them temporarily.
+
 2013-07-05         Andrew J. Schorr     <aschorr@telemetry-investments.com>
 
 	* gawkapi.h (gawk_api): Document that the api_get_file function will not
diff --git a/configh.in b/configh.in
index 68d5bf76..999e5db5 100644
--- a/configh.in
+++ b/configh.in
@@ -171,6 +171,9 @@
 /* Define to 1 if you have the `setsid' function. */
 #undef HAVE_SETSID
 
+/* Define to 1 if you have the `sigprocmask' function. */
+#undef HAVE_SIGPROCMASK
+
 /* Define to 1 if you have the `snprintf' function. */
 #undef HAVE_SNPRINTF
 
diff --git a/configure b/configure
index fccfcea0..62f0413d 100755
--- a/configure
+++ b/configure
@@ -10018,7 +10018,8 @@ esac
 for ac_func in atexit btowc fmod getgrent getgroups grantpt \
 	isascii iswctype iswlower iswupper mbrlen \
 	memcmp memcpy memcpy_ulong memmove memset \
-	memset_ulong mkstemp posix_openpt setenv setlocale setsid snprintf strchr \
+	memset_ulong mkstemp posix_openpt setenv setlocale setsid sigprocmask \
+	snprintf strchr \
 	strerror strftime strncasecmp strcoll strtod strtoul \
 	system tmpfile towlower towupper tzset usleep waitpid wcrtomb \
 	wcscoll wctype
diff --git a/configure.ac b/configure.ac
index ba242c51..9f2878b0 100644
--- a/configure.ac
+++ b/configure.ac
@@ -274,7 +274,8 @@ esac
 AC_CHECK_FUNCS(atexit btowc fmod getgrent getgroups grantpt \
 	isascii iswctype iswlower iswupper mbrlen \
 	memcmp memcpy memcpy_ulong memmove memset \
-	memset_ulong mkstemp posix_openpt setenv setlocale setsid snprintf strchr \
+	memset_ulong mkstemp posix_openpt setenv setlocale setsid sigprocmask \
+	snprintf strchr \
 	strerror strftime strncasecmp strcoll strtod strtoul \
 	system tmpfile towlower towupper tzset usleep waitpid wcrtomb \
 	wcscoll wctype)
diff --git a/io.c b/io.c
index 42c92e47..01dc7cbe 100644
--- a/io.c
+++ b/io.c
@@ -2177,17 +2177,34 @@ use_pipes:
  *
  * Note: on platforms that do not support waitpid with WNOHANG, when called with
  * a zero argument, this function will hang until all children have exited.
+ *
+ * AJS, 2013-07-07: I do not see why we need to ignore signals during this
+ * function.  This function just waits and updates the pid and status fields.
+ * I don't see why that should interfere with any signal handlers.  But I am
+ * reluctant to remove this protection.  So I changed to use sigprocmask to
+ * block signals instead to avoid interfering with installed signal handlers.
  */
 
 static int
 wait_any(int interesting)	/* pid of interest, if any */
 {
-	RETSIGTYPE (*hstat)(int), (*istat)(int), (*qstat)(int);
 	int pid;
 	int status = 0;
 	struct redirect *redp;
+#ifdef HAVE_SIGPROCMASK
+	sigset_t set, oldset;
+
+	/* I have no idea why we are blocking signals during this function... */
+	sigemptyset(& set);
+	sigaddset(& set, SIGINT);
+	sigaddset(& set, SIGHUP);
+	sigaddset(& set, SIGQUIT);
+	sigprocmask(SIG_BLOCK, & set, & oldset);
+#else
+	RETSIGTYPE (*hstat)(int), (*istat)(int), (*qstat)(int);
 
 	istat = signal(SIGINT, SIG_IGN);
+#endif
 #ifdef __MINGW32__
 	if (interesting < 0) {
 		status = -1;
@@ -2204,8 +2221,10 @@ wait_any(int interesting)	/* pid of interest, if any */
 			}
 	}
 #else
+#ifndef HAVE_SIGPROCMASK
 	hstat = signal(SIGHUP, SIG_IGN);
 	qstat = signal(SIGQUIT, SIG_IGN);
+#endif
 	for (;;) {
 # if defined(HAVE_WAITPID) && defined(WNOHANG)
 		if ((pid = waitpid(-1, & status, WNOHANG)) == 0)
@@ -2229,10 +2248,16 @@ wait_any(int interesting)	/* pid of interest, if any */
 		if (pid == -1 && errno == ECHILD)
 			break;
 	}
+#ifndef HAVE_SIGPROCMASK
 	signal(SIGHUP, hstat);
 	signal(SIGQUIT, qstat);
 #endif
+#endif
+#ifndef HAVE_SIGPROCMASK
 	signal(SIGINT, istat);
+#else
+	sigprocmask(SIG_SETMASK, & oldset, NULL);
+#endif
 	return status;
 }