fix: construct Plan 9 paths without truncation

srv.c

@@ -74,14 +74,16 @@ clientthread(void *arg)
 static void
 srvinit(void)
 {
-	char addr[128], path[sizeof(((struct sockaddr_un*)0)->sun_path)];
+	char *addr, path[sizeof(((struct sockaddr_un*)0)->sun_path)];
 
 	if(ipcpath(path, sizeof path) < 0)
 		die("IPC path is too long");
-	if(snprint(addr, sizeof addr, "unix!%s", path) >= (int)sizeof addr)
-		die("IPC address is too long");
+	addr = smprint("unix!%s", path);
+	if(addr == nil)
+		die("out of memory");
 	if(announce(addr, adir) < 0)
 		die("IPC endpoint is already in use: %r");
+	free(addr);
 	if(chmod(path, 0600) < 0)
 		die("can't protect IPC endpoint: %s", path);
 }