commit 27fa3123f917c3af7e914d4a082fe96ef518e6f7
author Vladimir Homutov <vl@nginx.com> Tue Aug 26 14:56:54 2014 +0400
committer Vladimir Homutov <vl@nginx.com> Tue Aug 26 14:56:54 2014 +0400
tree 8850ca8440688f8cfeead144905cf39fccd0f247
parent d79cbf15e6ba119767d2a035047ff67c19465961

Syslog: improved error handling of unix domain sockets.

If a syslog daemon is restarted and the unix socket is used, further logging
might stop to work.  In case of send error, socket is closed, forcing
a reconnection at the next logging attempt.

src/core/ngx_syslog.c

diff --git a/src/core/ngx_syslog.c b/src/core/ngx_syslog.c
index 2555f29..616fd71 100644
--- a/src/core/ngx_syslog.c
+++ b/src/core/ngx_syslog.c
@@ -261,6 +261,8 @@
 ssize_t
 ngx_syslog_send(ngx_syslog_peer_t *peer, u_char *buf, size_t len)
 {
+    ssize_t  n;
+
     if (peer->conn.fd == (ngx_socket_t) -1) {
         if (ngx_syslog_init_peer(peer) != NGX_OK) {
             return NGX_ERROR;
@@ -271,12 +273,28 @@
     peer->conn.log = ngx_cycle->log;
 
     if (ngx_send) {
-        return ngx_send(&peer->conn, buf, len);
+        n = ngx_send(&peer->conn, buf, len);
 
     } else {
         /* event module has not yet set ngx_io */
-        return ngx_os_io.send(&peer->conn, buf, len);
+        n = ngx_os_io.send(&peer->conn, buf, len);
     }
+
+#if (NGX_HAVE_UNIX_DOMAIN)
+
+    if (n == NGX_ERROR && peer->server.sockaddr->sa_family == AF_UNIX) {
+
+        if (ngx_close_socket(peer->conn.fd) == -1) {
+            ngx_log_error(NGX_LOG_ALERT, ngx_cycle->log, ngx_socket_errno,
+                          ngx_close_socket_n " failed");
+        }
+
+        peer->conn.fd = (ngx_socket_t) -1;
+    }
+
+#endif
+
+    return n;
 }
 
 
@@ -344,6 +362,10 @@
     /* prevents further use of this peer */
     peer->busy = 1;
 
+    if (peer->conn.fd == (ngx_socket_t) -1) {
+        return;
+    }
+
     if (ngx_close_socket(peer->conn.fd) == -1) {
         ngx_log_error(NGX_LOG_ALERT, ngx_cycle->log, ngx_socket_errno,
                       ngx_close_socket_n " failed");