HDFS-8407. libhdfs hdfsListDirectory must set errno to 0 on success (Masatake Iwasaki via Colin P. McCabe)

hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt

@@ -813,6 +813,9 @@ Release 2.8.0 - UNRELEASED
     HDFS-8431. hdfs crypto class not found in Windows.
     (Anu Engineer via cnauroth)
 
+    HDFS-8407. hdfsListDirectory must set errno to 0 on success (Masatake
+    Iwasaki via Colin P. McCabe)
+
 Release 2.7.1 - UNRELEASED
 
   INCOMPATIBLE CHANGES

hadoop-hdfs-project/hadoop-hdfs/src/main/native/libhdfs/expect.h

@@ -48,6 +48,24 @@ struct hdfsFile_internal;
         } \
     } while (0);
 
+#define EXPECT_NULL_WITH_ERRNO(x, e) \
+    do { \
+        const void* __my_ret__ = x; \
+        int __my_errno__ = errno; \
+        if (__my_ret__ != NULL) { \
+            fprintf(stderr, "TEST_ERROR: failed on %s:%d (errno: %d): " \
+		    "got non-NULL value %p from %s\n", \
+		    __FILE__, __LINE__, __my_errno__, __my_ret__, #x); \
+            return -1; \
+        } \
+        if (__my_errno__ != e) { \
+            fprintf(stderr, "TEST_ERROR: failed on %s:%d (errno: %d): " \
+		    "got expected NULL without expected errno %d from %s\n", \
+		    __FILE__, __LINE__, __my_errno__, e, #x); \
+            return -1; \
+        } \
+    } while (0);
+
 #define EXPECT_NONNULL(x) \
     do { \
         const void* __my_ret__ = x; \

hadoop-hdfs-project/hadoop-hdfs/src/main/native/libhdfs/hdfs.c

@@ -3257,6 +3257,7 @@ done:
         return NULL;
     }
     *numEntries = jPathListSize;
+    errno = 0;
     return pathList;
 }
 

hadoop-hdfs-project/hadoop-hdfs/src/main/native/libhdfs/hdfs.h

@@ -671,7 +671,8 @@ extern  "C" {
      * @param path The path of the directory. 
      * @param numEntries Set to the number of files/directories in path.
      * @return Returns a dynamically-allocated array of hdfsFileInfo
-     * objects; NULL on error.
+     * objects; NULL on error or empty directory.
+     * errno is set to non-zero on error or zero on success.
      */
     LIBHDFS_EXTERNAL
     hdfsFileInfo *hdfsListDirectory(hdfsFS fs, const char* path,

hadoop-hdfs-project/hadoop-hdfs/src/main/native/libhdfs/test/test_libhdfs_ops.c

@@ -306,6 +306,15 @@ int main(int argc, char **argv) {
             fprintf(stderr, "waah! hdfsGetPathInfo for %s - FAILED!\n", slashTmp);
         }
 
+        fileList = 0;
+        fileList = hdfsListDirectory(fs, newDirectory, &numEntries);
+        if (!(fileList == NULL && numEntries == 0 && !errno)) {
+            fprintf(stderr, "waah! hdfsListDirectory for empty %s - FAILED!\n", newDirectory);
+            totalResult++;
+        } else {
+            fprintf(stderr, "hdfsListDirectory for empty %s - SUCCESS!\n", newDirectory);
+        }
+
         fileList = 0;
         if((fileList = hdfsListDirectory(fs, slashTmp, &numEntries)) != NULL) {
             for(i=0; i < numEntries; ++i) {

hadoop-hdfs-project/hadoop-hdfs/src/main/native/libhdfs/test_libhdfs_threaded.c

@@ -142,7 +142,7 @@ static int doTestHdfsOperations(struct tlhThreadInfo *ti, hdfsFS fs,
 {
     char tmp[4096];
     hdfsFile file;
-    int ret, expected;
+    int ret, expected, numEntries;
     hdfsFileInfo *fileInfo;
     struct hdfsReadStatistics *readStats = NULL;
 
@@ -153,6 +153,14 @@ static int doTestHdfsOperations(struct tlhThreadInfo *ti, hdfsFS fs,
 
     EXPECT_ZERO(doTestGetDefaultBlockSize(fs, paths->prefix));
 
+    /* There should be no entry in the directory. */
+    errno = EACCES; // see if errno is set to 0 on success
+    EXPECT_NULL_WITH_ERRNO(hdfsListDirectory(fs, paths->prefix, &numEntries), 0);
+    if (numEntries != 0) {
+        fprintf(stderr, "hdfsListDirectory set numEntries to "
+                "%d on empty directory.", numEntries);
+    }
+
     /* There should not be any file to open for reading. */
     EXPECT_NULL(hdfsOpenFile(fs, paths->file1, O_RDONLY, 0, 0, 0));
 
@@ -179,6 +187,13 @@ static int doTestHdfsOperations(struct tlhThreadInfo *ti, hdfsFS fs,
     EXPECT_ZERO(hdfsHSync(fs, file));
     EXPECT_ZERO(hdfsCloseFile(fs, file));
 
+    /* There should be 1 entry in the directory. */
+    EXPECT_NONNULL(hdfsListDirectory(fs, paths->prefix, &numEntries));
+    if (numEntries != 1) {
+        fprintf(stderr, "hdfsListDirectory set numEntries to "
+                "%d on directory containing 1 file.", numEntries);
+    }
+
     /* Let's re-open the file for reading */
     file = hdfsOpenFile(fs, paths->file1, O_RDONLY, 0, 0, 0);
     EXPECT_NONNULL(file);