Linux: create sockets with close-on-exec flag in thread-safe manner

[vlc] / src / network / udp.c

diff --git a/src/network/udp.c b/src/network/udp.c
index 8f6a18f499d88591a0e38ce8c78f815bda576f71..225eb192de23e060ef6fd80ec3fb8cfb38c620bc 100644 (file)
--- a/src/network/udp.c
+++ b/src/network/udp.c
@@ -151,7 +151,8 @@ static int net_ListenSingle (vlc_object_t *obj, const char *host, int port,
     if (host && !*host)
         host = NULL;
 
-    msg_Dbg (obj, "net: opening %s datagram port %d", host ?: "any", port);
+    msg_Dbg (obj, "net: opening %s datagram port %d",
+             host ? host : "any", port);
 
     int val = vlc_getaddrinfo (obj, host, port, &hints, &res);
     if (val)
@@ -166,25 +167,41 @@ static int net_ListenSingle (vlc_object_t *obj, const char *host, int port,
     for (const struct addrinfo *ptr = res; ptr != NULL; ptr = ptr->ai_next)
     {
         int fd = net_Socket (obj, ptr->ai_family, ptr->ai_socktype,
-                             protocol ?: ptr->ai_protocol);
+                             protocol ? protocol : ptr->ai_protocol);
         if (fd == -1)
         {
             msg_Dbg (obj, "socket error: %m");
             continue;
         }
 
-        if (ptr->ai_next != NULL)
-        {
 #ifdef IPV6_V6ONLY
-            if ((ptr->ai_family != AF_INET6)
-             || setsockopt (fd, SOL_IPV6, IPV6_V6ONLY, &(int){ 0 },
-                            sizeof (int)))
-#endif
-            {
-                msg_Err (obj, "Multiple network protocols present");
-                msg_Err (obj, "Please select network protocol manually");
-            }
+        /* If IPv6 was forced, set IPv6-only mode.
+         * If IPv4 was forced, do nothing extraordinary.
+         * If nothing was forced, try dual-mode IPv6. */
+        if (ptr->ai_family == AF_INET6)
+        {
+            int on = (family == AF_INET6);
+            setsockopt (fd, SOL_IPV6, IPV6_V6ONLY, &on, sizeof (on));
+        }
+        else if (ptr->ai_family == AF_INET && family == AF_UNSPEC)
+        {
+            for (const struct addrinfo *p = ptr; p != NULL; p = p->ai_next)
+                if (p->ai_family == AF_INET6)
+                {
+                    net_Close (fd);
+                    fd = -1;
+                    break;
+                }
+            if (fd == -1)
+                continue;
+        }
+#else
+        if (family == AF_UNSPEC && ptr->ai_next != NULL)
+        {
+            msg_Warn (obj, "ambiguous network protocol specification");
+            msg_Warn (obj, "please select IP version explicitly");
         }
+#endif
 
         fd = net_SetupDgramSocket( obj, fd, ptr );
         if( fd == -1 )
@@ -642,7 +659,7 @@ int __net_ConnectDgram( vlc_object_t *p_this, const char *psz_host, int i_port,
     int             i_val, i_handle = -1;
     bool      b_unreach = false;
 
-    if( i_hlim < 1 )
+    if( i_hlim < 0 )
         i_hlim = var_CreateGetInteger( p_this, "ttl" );
 
     memset( &hints, 0, sizeof( hints ) );
@@ -662,7 +679,7 @@ int __net_ConnectDgram( vlc_object_t *p_this, const char *psz_host, int i_port,
     {
         char *str;
         int fd = net_Socket (p_this, ptr->ai_family, ptr->ai_socktype,
-                             proto ?: ptr->ai_protocol);
+                             proto ? proto : ptr->ai_protocol);
         if (fd == -1)
             continue;
 
@@ -676,7 +693,7 @@ int __net_ConnectDgram( vlc_object_t *p_this, const char *psz_host, int i_port,
         setsockopt (fd, SOL_SOCKET, SO_BROADCAST, &(int){ 1 }, sizeof (int));
 #endif
 
-        if( i_hlim > 0 )
+        if( i_hlim >= 0 )
             net_SetMcastHopLimit( p_this, fd, ptr->ai_family, i_hlim );
 
         str = var_CreateGetNonEmptyString (p_this, "miface");
@@ -773,7 +790,7 @@ int __net_OpenDgram( vlc_object_t *obj, const char *psz_bind, int i_bind,
     for (struct addrinfo *ptr = loc; ptr != NULL; ptr = ptr->ai_next)
     {
         int fd = net_Socket (obj, ptr->ai_family, ptr->ai_socktype,
-                             protocol ?: ptr->ai_protocol);
+                             protocol ? protocol : ptr->ai_protocol);
         if (fd == -1)
             continue; // usually, address family not supported