object-storage: Use fchown instead of chown.

This is a step towards making fd based system calls where ever possible to avoid
path lookups.

Signed-off-by: Mohammed Junaid <junaid@redhat.com>
Change-Id: I482ea29ebe0859d0a5307ff25ecb5945d54bc7ca
Reviewed-on: http://review.gluster.org/5251
Reviewed-by: Peter Portante <pportant@redhat.com>
Tested-by: Peter Portante <pportant@redhat.com>

gluster/swift/common/DiskDir.py

@@ -16,7 +16,8 @@
 import os
 import errno
 
-from gluster.swift.common.fs_utils import dir_empty, rmdirs, mkdirs, os_path
+from gluster.swift.common.fs_utils import dir_empty, rmdirs, mkdirs, os_path, \
+    do_chown
 from gluster.swift.common.utils import validate_account, validate_container, \
     get_container_details, get_account_details, create_container_metadata, \
     create_account_metadata, DEFAULT_GID, get_container_metadata, \
@@ -454,7 +455,7 @@ class DiskDir(DiskCommon):
         if not self._dir_exists:
             mkdirs(self.datadir)
             # If we create it, ensure we own it.
-            os.chown(self.datadir, self.uid, self.gid)
+            do_chown(self.datadir, self.uid, self.gid)
         metadata = get_container_metadata(self.datadir)
         metadata[X_TIMESTAMP] = timestamp
         write_metadata(self.datadir, metadata)

gluster/swift/common/DiskFile.py

@@ -22,7 +22,7 @@ from swift.common.utils import renamer
 from swift.common.exceptions import DiskFileNotExist
 from gluster.swift.common.exceptions import AlreadyExistsAsDir
 from gluster.swift.common.fs_utils import mkdirs, rmdirs, do_open, do_close, \
-    do_unlink, do_chown, os_path, do_fsync
+    do_unlink, do_chown, os_path, do_fsync, do_fchown
 from gluster.swift.common.utils import read_metadata, write_metadata, \
     validate_object, create_object_metadata
 from gluster.swift.common.utils import X_CONTENT_LENGTH, X_CONTENT_TYPE, \
@@ -234,9 +234,9 @@ class Gluster_DiskFile(DiskFile):
                 tmp_path = os.path.join(tmp_path, dir_name)
                 self._create_dir_object(tmp_path)
 
+        do_fchown(fd, self.uid, self.gid)
         newpath = os.path.join(self.datadir, self._obj)
         renamer(self.tmppath, newpath)
-        do_chown(newpath, self.uid, self.gid)
         self.metadata = metadata
         self.data_file = newpath
         self.filter_metadata()

gluster/swift/common/fs_utils.py

@@ -74,6 +74,15 @@ def do_chown(path, uid, gid):
     return True
 
 
+def do_fchown(fd, uid, gid):
+    try:
+        os.fchown(fd, uid, gid)
+    except OSError as err:
+        logging.exception("fchown failed on %d err: %s", fd, err.strerror)
+        raise
+    return True
+
+
 def do_stat(path):
     try:
         #Check for fd.

test/unit/common/test_fs_utils.py

@@ -363,6 +363,45 @@ class TestFsUtils(unittest.TestCase):
         else:
             self.fail("Expected OSError")
 
+    def test_fchown(self):
+        tmpdir = mkdtemp()
+        try:
+            fd, tmpfile = mkstemp(dir=tmpdir)
+            buf = os.stat(tmpfile)
+            if buf.st_uid == 0:
+                raise SkipTest
+            else:
+                try:
+                    fs.do_fchown(fd, 20000, 20000)
+                except OSError as ex:
+                    if ex.errno != errno.EPERM:
+                        self.fail("Expected OSError")
+                else:
+                        self.fail("Expected OSError")
+        finally:
+            os.close(fd)
+            shutil.rmtree(tmpdir)
+
+    def test_fchown_err(self):
+        tmpdir = mkdtemp()
+        try:
+            fd, tmpfile = mkstemp(dir=tmpdir)
+            fd_rd = os.open(tmpfile, os.O_RDONLY)
+            buf = os.stat(tmpfile)
+            if buf.st_uid == 0:
+                raise SkipTest
+            else:
+                try:
+                    fs.do_fchown(fd_rd, 20000, 20000)
+                except OSError as ex:
+                    if ex.errno != errno.EPERM:
+                        self.fail("Expected OSError")
+                else:
+                    self.fail("Expected OSError")
+        finally:
+            os.close(fd_rd)
+            os.close(fd)
+            shutil.rmtree(tmpdir)
 
     def test_do_fsync(self):
         tmpdir = mkdtemp()