Merge pull request #554 from jnovy/540

Introduce pwarnf() for better diagnosis of socket/fd write issues.

Author: jnovy

src/conn_sock.c

@@ -558,13 +558,17 @@ static void sock_try_write_to_local_sock(struct remote_sock_s *sock)
 
 	if (local_sock->is_stream) {
 		w = write(*(local_sock->fd), sock->buf + sock->off, sock->remaining);
+		if (w < 0) {
+			pwarnf("Failed to write to fd %s", local_sock->label);
+		}
 	} else {
 		w = sendto(*(local_sock->fd), sock->buf + sock->off, sock->remaining, MSG_DONTWAIT | MSG_NOSIGNAL,
 			   (struct sockaddr *)local_sock->addr, sizeof(*(local_sock->addr)));
+		if (w < 0) {
+			pwarnf("Failed to write to socket %s", local_sock->label);
+		}
 	}
-	if (w < 0) {
-		nwarnf("Failed to write %s", local_sock->label);
-	} else {
+	if (w > 0) {
 		sock->off += w;
 		sock->remaining -= w;
 	}

src/utils.h

@@ -83,6 +83,22 @@ extern gboolean use_syslog;
 		exit(EXIT_FAILURE); \
 	} while (0)
 
+#define pwarn(s) \
+	do { \
+		fprintf(stderr, "[conmon:w]: %s %s\n", s, strerror(errno)); \
+		if (use_syslog) \
+			syslog(LOG_INFO, "conmon %.20s <pwarn>: %s %s\n", log_cid, s, strerror(errno)); \
+	} while (0)
+
+#define pwarnf(fmt, ...) \
+	if (log_level >= WARN_LEVEL) { \
+		do { \
+			fprintf(stderr, "[conmon:w]: " fmt " %s\n", ##__VA_ARGS__, strerror(errno)); \
+			if (use_syslog) \
+				syslog(LOG_INFO, "conmon %.20s <nwarn>: " fmt ": %s\n", log_cid, ##__VA_ARGS__, strerror(errno)); \
+		} while (0); \
+	}
+
 #define nwarn(s) \
 	if (log_level >= WARN_LEVEL) { \
 		do { \