socket: rework setting of struct sockaddr_un

Add a function to fill the Unix sockaddr for binding, connecting and
sending to avoid code duplication. Use memcpy() instead of snprintf()
and provide the minimum length of the address containing the terminating
null byte. This makes it easier to support abstract sockets if needed in
future (e.g. for systemd support).

diff --git a/socket.c b/socket.c
index 5b22db55714a851ece6d6b492ba8b83f4e54e1bf..9c7a52737f1d0a50c5240073decb42123cfb1c91 100644 (file)
--- a/socket.c
+++ b/socket.c
@@ -590,25 +590,40 @@ error:
 
 /* ================================================== */
 
+static socklen_t
+set_unix_sockaddr(struct sockaddr_un *sun, const char *addr)
+{
+  size_t len = strlen(addr);
+
+  if (len + 1 > sizeof (sun->sun_path)) {
+    DEBUG_LOG("Unix socket path %s too long", addr);
+    return 0;
+  }
+
+  memset(sun, 0, sizeof (*sun));
+  sun->sun_family = AF_UNIX;
+  memcpy(sun->sun_path, addr, len);
+
+  return offsetof(struct sockaddr_un, sun_path) + len + 1;
+}
+
+/* ================================================== */
+
 static int
 bind_unix_address(int sock_fd, const char *addr, int flags)
 {
   union sockaddr_all saddr;
+  socklen_t saddr_len;
 
-  memset(&saddr, 0, sizeof (saddr));
-
-  if (snprintf(saddr.un.sun_path, sizeof (saddr.un.sun_path), "%s", addr) >=
-      sizeof (saddr.un.sun_path)) {
-    DEBUG_LOG("Unix socket path %s too long", addr);
+  saddr_len = set_unix_sockaddr(&saddr.un, addr);
+  if (saddr_len == 0)
     return 0;
-  }
-  saddr.un.sun_family = AF_UNIX;
 
   if (unlink(addr) < 0)
     DEBUG_LOG("Could not remove %s : %s", addr, strerror(errno));
 
   /* PRV_BindSocket() doesn't support Unix sockets yet */
-  if (bind(sock_fd, &saddr.sa, sizeof (saddr.un)) < 0) {
+  if (bind(sock_fd, &saddr.sa, saddr_len) < 0) {
     DEBUG_LOG("Could not bind Unix socket to %s : %s", addr, strerror(errno));
     return 0;
   }
@@ -628,17 +643,13 @@ static int
 connect_unix_address(int sock_fd, const char *addr)
 {
   union sockaddr_all saddr;
+  socklen_t saddr_len;
 
-  memset(&saddr, 0, sizeof (saddr));
-
-  if (snprintf(saddr.un.sun_path, sizeof (saddr.un.sun_path), "%s", addr) >=
-      sizeof (saddr.un.sun_path)) {
-    DEBUG_LOG("Unix socket path %s too long", addr);
+  saddr_len = set_unix_sockaddr(&saddr.un, addr);
+  if (saddr_len == 0)
     return 0;
-  }
-  saddr.un.sun_family = AF_UNIX;
 
-  if (connect(sock_fd, &saddr.sa, sizeof (saddr.un)) < 0) {
+  if (connect(sock_fd, &saddr.sa, saddr_len) < 0) {
     DEBUG_LOG("Could not connect Unix socket to %s : %s", addr, strerror(errno));
     return 0;
   }
@@ -1142,14 +1153,9 @@ send_message(int sock_fd, SCK_Message *message, int flags)
                                            (struct sockaddr *)&saddr, sizeof (saddr));
       break;
     case SCK_ADDR_UNIX:
-      memset(&saddr, 0, sizeof (saddr));
-      if (snprintf(saddr.un.sun_path, sizeof (saddr.un.sun_path), "%s",
-                   message->remote_addr.path) >= sizeof (saddr.un.sun_path)) {
-        DEBUG_LOG("Unix socket path %s too long", message->remote_addr.path);
+      saddr_len = set_unix_sockaddr(&saddr.un, message->remote_addr.path);
+      if (saddr_len == 0)
         return 0;
-      }
-      saddr.un.sun_family = AF_UNIX;
-      saddr_len = sizeof (saddr.un);
       break;
     default:
       assert(0);