[hackers] [sbase][PATCH] concat: read(2): handle EINTR

From: Richard Ipsum <richardipsum_AT_fastmail.co.uk>
Date: Sun, 23 Jul 2017 10:13:50 +0100

On Linux we may receive EINTR if the read call is interrupted
before any data is read, if this is the case we can try to read
again.

---
 libutil/concat.c | 22 +++++++++++++++++-----
 1 file changed, 17 insertions(+), 5 deletions(-)
diff --git a/libutil/concat.c b/libutil/concat.c
index 2e9aa52..5cbadd2 100644
--- a/libutil/concat.c
+++ b/libutil/concat.c
_AT_@ -1,4 +1,5 @@
 /* See LICENSE file for copyright and license details. */
+#include <errno.h>
 #include <unistd.h>
 
 #include "../util.h"
_AT_@ -9,15 +10,26 @@ concat(int f1, const char *s1, int f2, const char *s2)
 	char buf[BUFSIZ];
 	ssize_t n;
 
-	while ((n = read(f1, buf, sizeof(buf))) > 0) {
+	for (;;) {
+		n = read(f1, buf, sizeof(buf));
+
+		if (n == 0)
+			break;
+
+		if (n < 0) {
+#ifdef __linux__
+			if (errno == EINTR)
+				continue;
+#endif
+			weprintf("read %s:", s1);
+			return -1;
+		}
+
 		if (writeall(f2, buf, n) < 0) {
 			weprintf("write %s:", s2);
 			return -2;
 		}
 	}
-	if (n < 0) {
-		weprintf("read %s:", s1);
-		return -1;
-	}
+
 	return 0;
 }
-- 
2.13.0

Received on Sun Jul 23 2017 - 11:13:50 CEST