Die with SIGPIPE when EPIPE happens on stdout.

5 files changed, 18 insertions, 4 deletions

diff --git a/ChangeLog b/ChangeLog
index d84b38c5..6822c6f4 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,12 @@
+2017-03-27         Arnold D. Robbins     <arnold@skeeve.com>
+
+	Cause EPIPE errors to stdout to generate a real SIGPIPE.
+
+	* awk.h (die_via_sigpipe): New macro.
+	* builtin.c (efwrite): Use it.
+	* io.c (non_fatal_flush_std_file): Ditto.
+	* main.c (usage): Ditto.
+
 2017-03-25         Arnold D. Robbins     <arnold@skeeve.com>
 
 	* io.c (flush_io): Use r_fatal and r_warning for messagefunc
diff --git a/awk.h b/awk.h
index 163ad362..c1e9b4a9 100644
--- a/awk.h
+++ b/awk.h
@@ -1966,7 +1966,9 @@ erealloc_real(void *ptr, size_t count, const char *where, const char *var, const
 #ifdef SIGPIPE
 #define ignore_sigpipe() signal(SIGPIPE, SIG_IGN)
 #define set_sigpipe_to_default() signal(SIGPIPE, SIG_DFL)
+#define die_via_sigpipe() (signal(SIGPIPE, SIG_DFL), kill(getpid(), SIGPIPE))
 #else
 #define ignore_sigpipe()
 #define set_sigpipe_to_default()
+#define die_via_sigpipe() exit(EXIT_FATAL)
 #endif
diff --git a/builtin.c b/builtin.c
index 0f2c62f8..e2143b36 100644
--- a/builtin.c
+++ b/builtin.c
@@ -129,9 +129,9 @@ wrerror:
 	if (errno == 0 || errno == EINVAL)
 		w32_maybe_set_errno();
 #endif
-	/* die silently on EPIPE to stdout */
+	/* for stdout, die with a real SIGPIPE, like other awks */
 	if (fp == stdout && errno == EPIPE)
-		gawk_exit(EXIT_SUCCESS);	// a la SIGPIPE
+		die_via_sigpipe();
 
 	/* otherwise die verbosely */
 	if ((rp != NULL) ? is_non_fatal_redirect(rp->value, strlen(rp->value)) : is_non_fatal_std(fp))
diff --git a/io.c b/io.c
index fa9225ce..b00f4db4 100644
--- a/io.c
+++ b/io.c
@@ -1400,7 +1400,7 @@ non_fatal_flush_std_file(FILE *fp)
 
 		if (is_fatal) {
 			if (errno == EPIPE)
-				exit(EXIT_SUCCESS);	// simulate SIGPIPE
+				die_via_sigpipe();
 			else
 				fatal(fp == stdout
 					? _("fflush: cannot flush standard output: %s")
diff --git a/main.c b/main.c
index 4f578d3e..73e63448 100644
--- a/main.c
+++ b/main.c
@@ -633,7 +633,10 @@ By default it reads standard input and writes standard output.\n\n"), fp);
 				warning(_("error writing standard output (%s)"), strerror(errno));
 			else if (fp == stderr)
 				warning(_("error writing standard error (%s)"), strerror(errno));
-		}
+		} else if (errno == SIGPIPE)
+			die_via_sigpipe();
+
+		// some other problem than SIGPIPE
 		exit(EXIT_FAILURE);
 	}