GUACAMOLE-249: Clean up basename logic of file downloads. Add unit test.

src/protocols/rdp/download.c

@@ -193,38 +193,20 @@ void* guac_rdp_download_to_user(guac_user* user, void* data) {
     /* If file opened successfully, start stream */
     if (file_id >= 0) {
 
-        guac_rdp_download_status* download_status;
-        const char* basename;
-
-        int i;
-        char c;
-
         /* Associate stream with transfer status */
         guac_stream* stream = guac_user_alloc_stream(user);
-        stream->data = download_status = malloc(sizeof(guac_rdp_download_status));
+        guac_rdp_download_status* download_status = malloc(sizeof(guac_rdp_download_status));
+        stream->data = download_status;
         stream->ack_handler = guac_rdp_download_ack_handler;
         download_status->file_id = file_id;
         download_status->offset = 0;
 
-        /* Get basename from absolute path */
-        i=0;
-        basename = path;
-        do {
-
-            c = path[i];
-            if (c == '/' || c == '\\')
-                basename = &(path[i+1]);
-
-            i++;
-
-        } while (c != '\0');
-
         guac_user_log(user, GUAC_LOG_DEBUG, "%s: Initiating download "
                 "of \"%s\"", __func__, path);
 
         /* Begin stream */
         guac_protocol_send_file(user->socket, stream,
-                "application/octet-stream", basename);
+                "application/octet-stream", guac_rdp_fs_basename(path));
         guac_socket_flush(user->socket);
 
         /* Download started successfully */

src/protocols/rdp/fs.c

@@ -605,6 +605,21 @@ const char* guac_rdp_fs_read_dir(guac_rdp_fs* fs, int file_id) {
 
 }
 
+const char* guac_rdp_fs_basename(const char* path) {
+
+    for (const char* c = path; *c != '\0'; c++) {
+
+        /* Reset beginning of path if a path separator is found */
+        if (*c == '/' || *c == '\\')
+            path = c + 1;
+
+    }
+
+    /* path now points to the first character after the last path separator */
+    return path;
+
+}
+
 int guac_rdp_fs_normalize_path(const char* path, char* abs_path) {
 
     int path_depth = 0;

src/protocols/rdp/fs.h

@@ -524,6 +524,20 @@ int guac_rdp_fs_truncate(guac_rdp_fs* fs, int file_id, int length);
  */
 void guac_rdp_fs_close(guac_rdp_fs* fs, int file_id);
 
+/**
+ * Given an arbitrary path, returns a pointer to the first character following
+ * the last path separator in the path (the basename of the path). For example,
+ * given "/foo/bar/baz" or "\foo\bar\baz", this function would return a pointer
+ * to "baz".
+ *
+ * @param path
+ *     The path to determine the basename of.
+ *
+ * @return
+ *     A pointer to the first character of the basename within the path.
+ */
+const char* guac_rdp_fs_basename(const char* path);
+
 /**
  * Given an arbitrary path, which may contain ".." and ".", creates an
  * absolute path which does NOT contain ".." or ".". The given path MUST

src/protocols/rdp/tests/Makefile.am

@@ -34,6 +34,7 @@ check_PROGRAMS = test_rdp
 TESTS = $(check_PROGRAMS)
 
 test_rdp_SOURCES =      \
+    fs/basename.c       \
     fs/normalize_path.c
 
 test_rdp_CFLAGS =                \

src/protocols/rdp/tests/fs/basename.c

@@ -0,0 +1,59 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+#include "fs.h"
+
+#include <CUnit/CUnit.h>
+#include <stdlib.h>
+
+/**
+ * Test which verifies basenames are correctly extracted from Windows-style
+ * paths.
+ */
+void test_fs__basename_windows() {
+    CU_ASSERT_STRING_EQUAL(guac_rdp_fs_basename("\\foo\\bar\\baz"), "baz")
+    CU_ASSERT_STRING_EQUAL(guac_rdp_fs_basename("\\foo\\bar\\..\\baz\\"), "")
+    CU_ASSERT_STRING_EQUAL(guac_rdp_fs_basename("bar\\..\\..\\baz\\a\\..\\b"), "b")
+    CU_ASSERT_STRING_EQUAL(guac_rdp_fs_basename(".\\bar\\potato"), "potato")
+    CU_ASSERT_STRING_EQUAL(guac_rdp_fs_basename("..\\..\\..\\..\\..\\..\\baz"), "baz")
+}
+
+/**
+ * Test which verifies basenames are correctly extracted from UNIX-style paths.
+ */
+void test_fs__basename_unix() {
+    CU_ASSERT_STRING_EQUAL(guac_rdp_fs_basename("/foo/bar/baz"), "baz")
+    CU_ASSERT_STRING_EQUAL(guac_rdp_fs_basename("/foo/bar/../baz/"), "")
+    CU_ASSERT_STRING_EQUAL(guac_rdp_fs_basename("bar/../../baz/a/../b"), "b")
+    CU_ASSERT_STRING_EQUAL(guac_rdp_fs_basename("./bar/potato"), "potato")
+    CU_ASSERT_STRING_EQUAL(guac_rdp_fs_basename("../../../../../../baz"), "baz")
+}
+
+/**
+ * Test which verifies basenames are correctly extracted from paths consisting
+ * of mixed Windows and UNIX path separators.
+ */
+void test_fs__basename_mixed() {
+    CU_ASSERT_STRING_EQUAL(guac_rdp_fs_basename("\\foo/bar\\baz"), "baz")
+    CU_ASSERT_STRING_EQUAL(guac_rdp_fs_basename("/foo\\bar/..\\baz/"), "")
+    CU_ASSERT_STRING_EQUAL(guac_rdp_fs_basename("bar\\../../baz\\a\\..\\b"), "b")
+    CU_ASSERT_STRING_EQUAL(guac_rdp_fs_basename(".\\bar/potato"), "potato")
+    CU_ASSERT_STRING_EQUAL(guac_rdp_fs_basename("../..\\..\\..\\../..\\baz"), "baz")
+}
+