X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=net.c;fp=net.c;h=023d78d08175f2f3810af6dd387f5eec14a06dcc;hp=fa7cd4b80a7d96b26e35add01ad97d9a123f138d;hb=29f363373fa252c720d34893b8283bedcda53a49;hpb=28b9dcf18ec333883fb53e6e7a5920345d2ba9ee

diff --git a/net.c b/net.c
index fa7cd4b8..023d78d0 100644
--- a/net.c
+++ b/net.c
@@ -818,25 +818,37 @@ int dccp_available_ccids(uint8_t **ccid_array)
 	return nccids;
 }
 
-/**
- * Prepare a structure for \p AF_UNIX socket addresses.
- *
- * \param u Pointer to the struct to be prepared.
- * \param name The socket pathname.
+/*
+ * Prepare a structure for AF_UNIX socket addresses.
  *
- * This just copies \a name to the sun_path component of \a u.
+ * This just copies name to the sun_path component of u, prepending a zero byte
+ * if abstract sockets are supported.
  *
- * \return Positive on success, \p -E_NAME_TOO_LONG if \a name is longer
- * than \p UNIX_PATH_MAX.
+ * The first call to this function tries to bind a socket to the abstract name
+ * space. The result of this test is stored in a static variable. Subsequent
+ * calls read this variable and create abstract sockets on systems that support
+ * them.
  */
-static int init_unix_addr(struct sockaddr_un *u, const char *name,
-		bool abstract)
+static int init_unix_addr(struct sockaddr_un *u, const char *name)
 {
-	if (strlen(name) + abstract >= UNIX_PATH_MAX)
+	static int use_abstract;
+
+	if (strlen(name) + 1 >= UNIX_PATH_MAX)
 		return -E_NAME_TOO_LONG;
 	memset(u->sun_path, 0, UNIX_PATH_MAX);
 	u->sun_family = PF_UNIX;
-	strcpy(u->sun_path + abstract, name);
+	if (use_abstract == 0) { /* executed only once */
+		int fd = socket(PF_UNIX, SOCK_STREAM, 0);
+		memcpy(u->sun_path, "\0x\0", 3);
+		if (bind(fd, (struct sockaddr *)u, sizeof(*u)) == 0)
+			use_abstract = 1; /* yes */
+		else
+			use_abstract = -1; /* no */
+		close(fd);
+		PARA_NOTICE_LOG("%susing abstract socket namespace\n",
+			use_abstract == 1? "" : "not ");
+	}
+	strcpy(u->sun_path + (use_abstract == 1? 1 : 0), name);
 	return 1;
 }
 
@@ -844,28 +856,22 @@ static int init_unix_addr(struct sockaddr_un *u, const char *name,
  * Create a socket for local communication and listen on it.
  *
  * \param name The socket pathname.
- * \param mode The desired permissions of the socket.
  *
  * This function creates a passive local socket for sequenced, reliable,
  * two-way, connection-based byte streams. The socket file descriptor is set to
  * nonblocking mode and listen(2) is called to prepare the socket for
  * accepting incoming connection requests.
  *
- * If mode is zero, an abstract socket (a non-portable Linux extension) is
- * created. In this case the socket name has no connection with filesystem
- * pathnames.
- *
  * \return The file descriptor on success, negative error code on failure.
  *
  * \sa socket(2), \sa bind(2), \sa chmod(2), listen(2), unix(7).
  */
-int create_local_socket(const char *name, mode_t mode)
+int create_local_socket(const char *name)
 {
 	struct sockaddr_un unix_addr;
 	int fd, ret;
-	bool abstract = mode == 0;
 
-	ret = init_unix_addr(&unix_addr, name, abstract);
+	ret = init_unix_addr(&unix_addr, name);
 	if (ret < 0)
 		return ret;
 	ret = socket(PF_UNIX, SOCK_STREAM, 0);
@@ -880,7 +886,9 @@ int create_local_socket(const char *name, mode_t mode)
 		ret = -ERRNO_TO_PARA_ERROR(errno);
 		goto err;
 	}
-	if (!abstract) {
+	if (unix_addr.sun_path[0] != 0) { /* pathname socket */
+		mode_t mode = S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP
+			| S_IROTH | S_IWOTH;
 		ret = -E_CHMOD;
 		if (chmod(name, mode) < 0)
 			goto err;
@@ -917,14 +925,7 @@ int connect_local_socket(const char *name)
 	fd = socket(PF_UNIX, SOCK_STREAM, 0);
 	if (fd < 0)
 		return -ERRNO_TO_PARA_ERROR(errno);
-	/* first try (linux-only) abstract socket */
-	ret = init_unix_addr(&unix_addr, name, true);
-	if (ret < 0)
-		goto err;
-	if (connect(fd, (struct sockaddr *)&unix_addr, sizeof(unix_addr)) != -1)
-		return fd;
-	/* next try pathname socket */
-	ret = init_unix_addr(&unix_addr, name, false);
+	ret = init_unix_addr(&unix_addr, name);
 	if (ret < 0)
 		goto err;
 	if (connect(fd, (struct sockaddr *)&unix_addr, sizeof(unix_addr)) != -1)