SNOW-1958601: Fix NPE when cache folder is inaccessible (#2108)

Author: sfc-gh-pbulawa

src/main/java/net/snowflake/client/core/FileCacheManager.java

@@ -91,8 +91,8 @@ synchronized String getCacheFilePath() {
    * @param newCacheFile a file object to override the default one.
    */
   synchronized void overrideCacheFile(File newCacheFile) {
-    if (!newCacheFile.exists()) {
-      logger.debug("Cache file doesn't exists. File: {}", newCacheFile);
+    if (!FileUtil.exists(newCacheFile)) {
+      logger.debug("Cache file doesn't exist. File: {}", newCacheFile);
     }
     if (onlyOwnerPermissions) {
       FileUtil.handleWhenFilePermissionsWiderThanUserOnly(newCacheFile, "Override cache file");
@@ -264,8 +264,8 @@ synchronized <T> T withLock(Supplier<T> supplier) {
   /** Reads the cache file. */
   synchronized JsonNode readCacheFile() {
     try {
-      if (!cacheFile.exists()) {
-        logger.debug("Cache file doesn't exists. File: {}", cacheFile);
+      if (!FileUtil.exists(cacheFile)) {
+        logger.debug("Cache file doesn't exist. File: {}", cacheFile);
         return null;
       }
 
@@ -373,8 +373,8 @@ private synchronized void deleteCacheLockIfExpired() {
    * @return epoch time in ms
    */
   private static synchronized long fileCreationTime(File targetFile) {
-    if (!targetFile.exists()) {
-      logger.debug("File not exists. File: {}", targetFile);
+    if (!FileUtil.exists(targetFile)) {
+      logger.debug("File does not exist. File: {}", targetFile);
       return -1;
     }
     try {

src/main/java/net/snowflake/client/core/FileUtil.java

@@ -134,14 +134,14 @@ private static void logWarnWhenAccessibleByOthers(
       boolean isReadableByOthers = isPermPresent(filePermissions, READ_BY_OTHERS);
       boolean isExecutable = isPermPresent(filePermissions, EXECUTABLE);
 
-      if (isWritableByOthers || (isReadableByOthers || isExecutable)) {
+      if (isWritableByOthers || (isReadableByOthers && logReadAccess) || isExecutable) {
         logger.warn(
             "{}File {} is accessible by others to:{}{}",
             getContextStr(context),
             filePath,
             isReadableByOthers && logReadAccess ? " read" : "",
             isWritableByOthers ? " write" : "",
-            isExecutable ? " executable" : "");
+            isExecutable ? " execute" : "");
       }
     } catch (IOException e) {
       logger.warn(
@@ -192,4 +192,11 @@ static String getFileOwnerName(Path filePath) throws IOException {
   private static String getContextStr(String context) {
     return Strings.isNullOrEmpty(context) ? "" : context + ": ";
   }
+
+  public static boolean exists(File file) {
+    if (file == null) {
+      return false;
+    }
+    return file.exists();
+  }
 }

src/test/java/net/snowflake/client/core/FileCacheManagerTest.java

@@ -104,6 +104,26 @@ public void throwWhenReadCacheFileWithPermissionDifferentThanReadWriteForUserTes
     }
   }
 
+  @Test
+  @RunOnLinuxOrMac
+  public void notThrowExceptionWhenCacheFolderIsNotAccessible() throws IOException {
+    try {
+      Files.setPosixFilePermissions(
+          cacheFile.getParentFile().toPath(), PosixFilePermissions.fromString("---------"));
+      FileCacheManager fcm =
+          FileCacheManager.builder()
+              .setCacheDirectorySystemProperty(CACHE_DIR_PROP)
+              .setCacheDirectoryEnvironmentVariable(CACHE_DIR_ENV)
+              .setBaseCacheFileName(CACHE_FILE_NAME)
+              .setCacheFileLockExpirationInSeconds(CACHE_FILE_LOCK_EXPIRATION_IN_SECONDS)
+              .build();
+      assertDoesNotThrow(fcm::readCacheFile);
+    } finally {
+      Files.setPosixFilePermissions(
+          cacheFile.getParentFile().toPath(), PosixFilePermissions.fromString("rwx------"));
+    }
+  }
+
   @Test
   @RunOnLinuxOrMac
   public void throwWhenOverrideCacheFileHasDifferentOwnerThanCurrentUserTest() {