Merge pull request #206 from satken2/sakten2_issue111

Fixed sysctl to work on symlinks

SUMMARY
Fixes #111.
This issue reports a bug of sysctl that the module does not work properly when sysctl_file is a symlink.
I Fixed the bug by inserting os.path.realpath to get real path.
When sysctl_file is a real file, os.path.realpath return the original path as is.
ISSUE TYPE

Bugfix Pull Request

COMPONENT NAME
sysctl
ADDITIONAL INFORMATION


I have executed the script described in #111 and confirmed that it works properly.
But I need to add some tests.

satken@dockerhost1:~/ansible$ sudo docker run --rm -v ${PWD}:/work -w /work -e ANSIBLE_LIBRARY=/work/ansible.posix -e ANSIBLE_HOST_KEY_CHECKING=False satken2/ansible:3.3.0 ansible-playbook -i hosts main.yml

PLAY [test] ********************************************************************

TASK [Gathering Facts] *********************************************************
ok: [192.168.91.76]

TASK [test] ********************************************************************
ok: [192.168.91.76] => {
    "msg": "This is test"
}

TASK [command] *****************************************************************
changed: [192.168.91.76]

TASK [command] *****************************************************************
ok: [192.168.91.76]

TASK [debug] *******************************************************************
ok: [192.168.91.76] => {
    "sysctl_current_value.stdout": "kernel.randomize_va_space = 2"
}

TASK [copy] ********************************************************************
changed: [192.168.91.76]

TASK [file] ********************************************************************
changed: [192.168.91.76]

TASK [stat] ********************************************************************
ok: [192.168.91.76]

TASK [assert] ******************************************************************
ok: [192.168.91.76] => {
    "changed": false,
    "msg": "/tmp/ansible_sysctl_test_symlink.conf is correct symlink"
}

TASK [sysctl | enable randomized layout of virtual address space] **************
changed: [192.168.91.76]

TASK [stat] ********************************************************************
ok: [192.168.91.76]

TASK [assert] ******************************************************************
ok: [192.168.91.76] => {
    "changed": false,
    "msg": "/tmp/ansible_sysctl_test_symlink.conf is correct symlink"
}

PLAY RECAP *********************************************************************
192.168.91.76              : ok=12   changed=4    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0

Reviewed-by: quidame
Reviewed-by: Jill R

changelogs/fragments/206_fix_sysctl_to_work_on_symlinks.yml

@@ -0,0 +1,3 @@
+---
+bugfixes:
+- sysctl - fix sysctl to work properly on symlinks (https://github.com/ansible-collections/ansible.posix/issues/111).

plugins/modules/sysctl.py

@@ -366,7 +366,7 @@ class SysctlModule(object):
     # Completely rewrite the sysctl file
     def write_sysctl(self):
         # open a tmp file
-        fd, tmp_path = tempfile.mkstemp('.conf', '.ansible_m_sysctl_', os.path.dirname(self.sysctl_file))
+        fd, tmp_path = tempfile.mkstemp('.conf', '.ansible_m_sysctl_', os.path.dirname(os.path.realpath(self.sysctl_file)))
         f = open(tmp_path, "w")
         try:
             for l in self.fixed_lines:
@@ -377,7 +377,7 @@ class SysctlModule(object):
         f.close()
 
         # replace the real one
-        self.module.atomic_move(tmp_path, self.sysctl_file)
+        self.module.atomic_move(tmp_path, os.path.realpath(self.sysctl_file))
 
 
 # ==============================================================

tests/integration/targets/sysctl/tasks/main.yml

@@ -332,3 +332,37 @@
         that:
           - sysctl_invalid_set1 is failed
           - "'vm.mmap_rnd_bits' not in sysctl_invalid_conf_content.stdout"
+
+    # Test sysctl: sysctl_file is symlink
+    - name: Create link source
+      ansible.builtin.copy:
+        content: |
+          # Testing Ansible Sysctl module on symlink.
+        dest: /tmp/ansible_sysctl_test.conf
+        mode: "0644"
+
+    - name: Create symlink to the conf file
+      ansible.builtin.file:
+        src: /tmp/ansible_sysctl_test.conf
+        dest: /tmp/ansible_sysctl_test_symlink.conf
+        state: link
+
+    - name: Use sysctl module with symlink sysctl file
+      ansible.posix.sysctl:
+        name: 'kernel.randomize_va_space'
+        value: '1'
+        sysctl_file: /tmp/ansible_sysctl_test_symlink.conf
+        state: present
+        sysctl_set: false
+        reload: false
+
+    - name: Stat sysctl file
+      ansible.builtin.stat:
+        path: /tmp/ansible_sysctl_test_symlink.conf
+      register: stat_result
+
+    - name: Ensure the sysctl file remains a symlink
+      ansible.builtin.assert:
+        that:
+          - stat_result.stat.islnk is defined and stat_result.stat.islnk
+          - stat_result.stat.lnk_source == '/tmp/ansible_sysctl_test.conf'