Changed socket interface to support fallbacks.

Now we support a list of fallback targets when opening the socket, and
socket binding/connect is done inside socket.* instead of luaa.c or
awesome-client.c

Signed-off-by: Alex Cornejo <acornejo@gmail.com>
Signed-off-by: Julien Danjou <julien@danjou.info>

awesome-client.c

@@ -56,17 +56,9 @@ sockets_init(void)
     if((csfd = socket_getclient()) < 0)
         return false;
 
-    if(!(addr = socket_getaddr(getenv("HOME"), display)))
+    if(!(addr = socket_open(csfd, display, SOCKET_MODE_CONNECT)))
         return false;
 
-    if(connect(csfd, addr, sizeof(struct sockaddr_un)) == -1)
-    {
-        if(!(addr = socket_getaddr("/tmp", display)))
-            return false;
-        if(connect(csfd, addr, sizeof(struct sockaddr_un)) == -1)
-            return false;
-    }
-
     return true;
 }
 

common/socket.c

@@ -24,6 +24,7 @@
 #include <errno.h>
 #include <sys/socket.h>
 #include <sys/un.h>
+#include <unistd.h>
 
 #include <xcb/xcb.h>
 
@@ -32,41 +33,75 @@
 
 #define CONTROL_UNIX_SOCKET_PATH ".awesome_ctl."
 
-/** Get a sockaddr_un struct with information feeded for opening a
+/** Open a communication socket with awesome for a given display.
- * communication to the awesome socket for given display
+ * \param csfd The socket file descriptor.
- * \param directory Where socket is created.
  * \param display the display number
- * \return sockaddr_un struct ready to be used or NULL if a problem occured
+ * \param mode The open mode, either Bind or Connect.
+ * \return sockaddr_un Struct ready to be used or NULL if a problem ocurred.
  */
 struct sockaddr_un *
-socket_getaddr(const char *directory, const char *display)
+socket_open(int csfd, const char *display, const socket_mode_t mode)
 {
     char *host = NULL;
     int screenp = 0, displayp = 0;
+    bool is_socket_opened = false;
     ssize_t path_len, len;
     struct sockaddr_un *addr;
+    const char *fallback[] = { ":HOME", ":TMPDIR", "/tmp", NULL }, *directory;
 
     addr = p_new(struct sockaddr_un, 1);
+    addr->sun_family = AF_UNIX;
 
     xcb_parse_display(NULL, &host, &displayp, &screenp);
-
     len = a_strlen(host);
 
-    /* + 2 for / and . and \0 */
+    for(int i = 0; fallback[i] && !is_socket_opened; i++)
-    path_len = snprintf(addr->sun_path, sizeof(addr->sun_path),
+    {
-                        "%s/" CONTROL_UNIX_SOCKET_PATH "%s%s%d",
+        if(fallback[i][0] == ':')
-                        directory, len ? host : "", len ? "." : "",
+        {
-                        displayp);
+            if(!(directory = getenv(fallback[i] + 1)))
+                continue;
+        }
+        else
+            directory = fallback[i];
+
+        /* + 2 for / and . and \0 */
+        path_len = snprintf(addr->sun_path, sizeof(addr->sun_path),
+                            "%s/" CONTROL_UNIX_SOCKET_PATH "%s%s%d",
+                            directory, len ? host : "", len ? "." : "",
+                            displayp);
+
+        if(path_len < ssizeof(addr->sun_path))
+            switch(mode)
+            {
+              case SOCKET_MODE_BIND:
+/* Needed for some OSes like Solaris */
+#ifndef SUN_LEN
+#define SUN_LEN(ptr) ((size_t) (((struct sockaddr_un *) 0)->sun_path) + strlen ((ptr)->sun_path))
+#endif
+                if(!bind(csfd, (const struct sockaddr *) addr, SUN_LEN(addr)))
+                    is_socket_opened = true;
+                else if(errno == EADDRINUSE)
+                {
+                    if(unlink(addr->sun_path))
+                        warn("error unlinking existing file: %s", strerror(errno));
+                    if(!bind(csfd, (const struct sockaddr *)addr, SUN_LEN(addr)))
+                        is_socket_opened = true;
+                }
+                break;
+              case SOCKET_MODE_CONNECT:
+                if(!connect(csfd, (const struct sockaddr *)addr, sizeof(struct sockaddr_un)))
+                    is_socket_opened = true;
+                break;
+            }
+        else
+            warn("error: path (using %s) of control UNIX domain socket is too long", directory);
+    }
 
     p_delete(&host);
 
-    if(path_len >= ssizeof(addr->sun_path))
+    if(!is_socket_opened)
-    {
+        p_delete(&addr);
-        fprintf(stderr, "error: path of control UNIX domain socket is too long");
-        return NULL;
-    }
-
-    addr->sun_family = AF_UNIX;
 
     return addr;
 }

common/socket.h

@@ -22,7 +22,13 @@
 #ifndef AWESOME_COMMON_SOCKET_H
 #define AWESOME_COMMON_SOCKET_H
 
-struct sockaddr_un * socket_getaddr(const char *, const char *);
+typedef enum
+{
+    SOCKET_MODE_BIND,
+    SOCKET_MODE_CONNECT
+} socket_mode_t;
+
+struct sockaddr_un *socket_open(const int, const char *, const socket_mode_t);
 int socket_getclient(void);
 
 #endif

luaa.c

@@ -1115,31 +1115,13 @@ luaA_cs_init(void)
     if (csfd < 0 || fcntl(csfd, F_SETFD, FD_CLOEXEC) == -1)
         return;
 
-    addr = socket_getaddr(getenv("HOME"), getenv("DISPLAY"));
+    if(!(addr = socket_open(csfd, getenv("DISPLAY"), SOCKET_MODE_BIND)))
-
-/* Needed for some OSes like Solaris */
-#ifndef SUN_LEN
-#define SUN_LEN(ptr) ((size_t) (((struct sockaddr_un *) 0)->sun_path) + strlen ((ptr)->sun_path))
-#endif
-
-    if(bind(csfd, (const struct sockaddr *) addr, SUN_LEN(addr)))
     {
-        if(errno == EADDRINUSE)
+        warn("error binding UNIX domain socket: %s", strerror(errno));
-        {
+        return;
-            if(unlink(addr->sun_path))
-                warn("error unlinking existing file: %s", strerror(errno));
-            if(bind(csfd, (const struct sockaddr *) addr, SUN_LEN(addr)))
-                return warn("error binding UNIX domain socket: %s", strerror(errno));
-        }
-        else
-        {
-            addr = socket_getaddr("/tmp", getenv("DISPLAY"));
-            if (bind(csfd, (const struct sockaddr *) addr, SUN_LEN(addr)))
-                return warn("error binding UNIX domain socket: %s", strerror(errno));
-        }
     }
-    listen(csfd, 10);
 
+    listen(csfd, 10);
     ev_io_init(&csio, &luaA_conn_cb, csfd, EV_READ);
     ev_io_start(EV_DEFAULT_UC_ &csio);
     ev_unref(EV_DEFAULT_UC);