dnsproxy: Handle TCP receive loop retries

On the TCP nonblocking socket, EAGAIN or EWOULDBLOCK recv() errors should
be handled more carefully.

Fixes BMC#9834

diff --git a/plugins/dnsproxy.c b/plugins/dnsproxy.c
index eae9a61..1c4a9e8 100644 (file)
--- a/plugins/dnsproxy.c
+++ b/plugins/dnsproxy.c
@@ -558,7 +558,7 @@ static gboolean tcp_server_event(GIOChannel *channel, GIOCondition condition,
 
                DBG("TCP reply %d bytes", reply_len);
 
-               reply = g_try_malloc(reply_len + 2);
+               reply = g_try_malloc0(reply_len + 2);
                if (reply == NULL)
                        return TRUE;
 
@@ -567,14 +567,25 @@ static gboolean tcp_server_event(GIOChannel *channel, GIOCondition condition,
 
                total_bytes_recv = bytes_recv = 0;
                while (total_bytes_recv < reply_len) {
-                       bytes_recv = recv(sk, reply + 2, reply_len, 0);
-                       if (bytes_recv < 0)
+                       bytes_recv = recv(sk, reply + 2 + total_bytes_recv,
+                                       reply_len - total_bytes_recv, 0);
+                       if (bytes_recv < 0) {
+                               if (errno == EAGAIN || errno == EWOULDBLOCK)
+                                       continue;
+
+                               connman_error("DNS proxy error %s",
+                                                       strerror(errno));
+
                                break;
+                       }
 
                        total_bytes_recv += bytes_recv;
                }
 
-               forward_dns_reply(reply, reply_len + 2, IPPROTO_TCP);
+               if (total_bytes_recv > reply_len)
+                       total_bytes_recv = reply_len;
+
+               forward_dns_reply(reply, total_bytes_recv + 2, IPPROTO_TCP);
 
                g_free(reply);