From 5626a4d593df9384fff5129e7bdb6c909f5f2b11 Mon Sep 17 00:00:00 2001

From: Maurizio Lombardi <mlombard@redhat.com>

Date: Fri, 8 Feb 2019 14:36:34 +0100

Subject: [PATCH] save_to_file() function breaks symbolic link when saving

 configuration

Currently the location of the targetcli configuration file is not

configurable (saveconfig.json). The location is : /etc/target

Some users use stateless VMs, with just a persistent device

mounted under /var/lib/diskless.

In order to circumvent the non configurable location of

saveconfig.json, they create a symbolic link in /etc/target

pointing to /var/lib/diskless

Unfortunately, the rtslib save_to_file() function breaks

this symbolic link and creates a new regular file in place of it,

due to the creation of a saveconfig.json.temp file which is

then renamed to saveconfig.json using the os.rename() function.

This patch replace os.rename() with shutil.copyfile() + os.remove(),

using copyfile() instead of rename() will preserve the symbolic link

Signed-off-by: Maurizio Lombardi <mlombard@redhat.com>

---

 rtslib/root.py | 8 ++++++--

 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/rtslib/root.py b/rtslib/root.py

index 5c0a98c..c93e65b 100644

--- a/rtslib/root.py

+++ b/rtslib/root.py

@@ -23,6 +23,7 @@ import stat

 import json

 import glob

 import errno

+import shutil

 from .node import CFSNode

 from .target import Target

@@ -386,7 +387,9 @@ class RTSRoot(CFSNode):

         else:

             saveconf = self.dump()

-        with open(save_file+".temp", "w+") as f:

+        tmp_file = save_file + ".temp"

+

+        with open(tmp_file, "w+") as f:

             os.fchmod(f.fileno(), stat.S_IRUSR | stat.S_IWUSR)

             f.write(json.dumps(saveconf, sort_keys=True, indent=2))

             f.write("\n")

@@ -394,7 +397,8 @@ class RTSRoot(CFSNode):

             os.fsync(f.fileno())

             f.close()

-        os.rename(save_file+".temp", save_file)

+        shutil.copyfile(tmp_file, save_file)

+        os.remove(tmp_file)

     def restore_from_file(self, restore_file=None, clear_existing=True, abort_on_error=False):

         '''

-- 

2.21.0