Tidy the code that works out the socket path, and just use the full path

in the global socket_path rather than copying it.

client.c

@@ -55,7 +55,7 @@ int		 client_attached;
 
 __dead void	client_exec(const char *);
 int		client_get_lock(char *);
-int		client_connect(struct event_base *, char *, int);
+int		client_connect(struct event_base *, const char *, int);
 void		client_send_identify(const char *, const char *);
 void		client_stdin_callback(int, short, void *);
 void		client_write(int, const char *, size_t);
@@ -96,7 +96,7 @@ client_get_lock(char *lockfile)
 
 /* Connect client to server. */
 int
-client_connect(struct event_base *base, char *path, int start_server)
+client_connect(struct event_base *base, const char *path, int start_server)
 {
 	struct sockaddr_un	sa;
 	size_t			size;

tmux.c

@@ -41,10 +41,10 @@ struct environ	*global_environ;
 
 char		*shell_cmd;
 struct timeval	 start_time;
-char		 socket_path[PATH_MAX];
+const char	*socket_path;
 
 __dead void	 usage(void);
-char 		*makesocketpath(const char *);
+static char	*make_label(const char *);
 
 __dead void
 usage(void)
@@ -102,38 +102,48 @@ areshell(const char *shell)
 	return (0);
 }
 
-char *
-makesocketpath(const char *label)
+static char *
+make_label(const char *label)
 {
-	char		base[PATH_MAX], realbase[PATH_MAX], *path, *s;
-	struct stat	sb;
-	u_int		uid;
+	char		*base, resolved[PATH_MAX], *path, *s;
+	struct stat	 sb;
+	u_int		 uid;
+	int		 saved_errno;
+
+	if (label == NULL)
+		label = "default";
 
 	uid = getuid();
+
 	if ((s = getenv("TMUX_TMPDIR")) != NULL && *s != '\0')
-		xsnprintf(base, sizeof base, "%s/tmux-%u", s, uid);
+		xasprintf(&base, "%s/tmux-%u", s, uid);
 	else
-		xsnprintf(base, sizeof base, "%s/tmux-%u", _PATH_TMP, uid);
+		xasprintf(&base, "%s/tmux-%u", _PATH_TMP, uid);
 
 	if (mkdir(base, S_IRWXU) != 0 && errno != EEXIST)
-		return (NULL);
+		goto fail;
 
 	if (lstat(base, &sb) != 0)
-		return (NULL);
+		goto fail;
 	if (!S_ISDIR(sb.st_mode)) {
 		errno = ENOTDIR;
-		return (NULL);
+		goto fail;
 	}
 	if (sb.st_uid != uid || (sb.st_mode & S_IRWXO) != 0) {
 		errno = EACCES;
-		return (NULL);
+		goto fail;
 	}
 
-	if (realpath(base, realbase) == NULL)
-		strlcpy(realbase, base, sizeof realbase);
-
-	xasprintf(&path, "%s/%s", realbase, label);
+	if (realpath(base, resolved) == NULL)
+		strlcpy(resolved, base, sizeof resolved);
+	xasprintf(&path, "%s/%s", resolved, label);
 	return (path);
+
+fail:
+	saved_errno = errno;
+	free(base);
+	errno = saved_errno;
+	return (NULL);
 }
 
 void
@@ -289,41 +299,23 @@ main(int argc, char **argv)
 	}
 
 	/*
-	 * Figure out the socket path. If specified on the command-line with -S
-	 * or -L, use it, otherwise try $TMUX or assume -L default.
+	 * If socket is specified on the command-line with -S or -L, it is
+	 * used. Otherwise, $TMUX is checked and if that fails "default" is
+	 * used.
 	 */
-	if (path == NULL) {
-		/* If no -L, use the environment. */
-		if (label == NULL) {
-			s = getenv("TMUX");
-			if (s != NULL) {
-				path = xstrdup(s);
-				path[strcspn (path, ",")] = '\0';
-				if (*path == '\0') {
-					free(path);
-					label = xstrdup("default");
-				}
-			} else
-				label = xstrdup("default");
-		}
-
-		/* -L or default set. */
-		if (label != NULL) {
-			if ((path = makesocketpath(label)) == NULL) {
-				fprintf(stderr, "can't create socket: %s\n",
-				    strerror(errno));
-				exit(1);
-			}
+	if (path == NULL && label == NULL) {
+		s = getenv("TMUX");
+		if (s != NULL && *s != '\0' && *s != ',') {
+			path = xstrdup(s);
+			path[strcspn (path, ",")] = '\0';
 		}
 	}
-	free(label);
-
-	if (strlcpy(socket_path, path, sizeof socket_path) >=
-	    sizeof socket_path) {
-		fprintf(stderr, "socket path too long: %s\n", path);
+	if (path == NULL && (path = make_label(label)) == NULL) {
+		fprintf(stderr, "can't create socket: %s\n", strerror(errno));
 		exit(1);
 	}
-	free(path);
+	socket_path = path;
+	free(label);
 
 	/* Pass control to the client. */
 	exit(client_main(event_init(), argc, argv, flags));

tmux.h

@@ -1433,7 +1433,7 @@ extern struct options *global_w_options;
 extern struct environ *global_environ;
 extern char		*shell_cmd;
 extern struct timeval	 start_time;
-extern char		 socket_path[PATH_MAX];
+extern const char	*socket_path;
 const char	*getshell(void);
 int		 checkshell(const char *);
 int		 areshell(const char *);