From b9bf1454ad729d3ab7df53a39d08e710124fb6ab Mon Sep 17 00:00:00 2001
From: Lucas Noki <lucas-noki@gmx.de>
Date: Tue, 28 Jan 2020 09:14:09 +0100
Subject: [PATCH] Add function to check for fstab entry, Prevent double entries

---
 modules/swap/module.py | 25 +++++++++++++++++++++----
 1 file changed, 21 insertions(+), 4 deletions(-)

diff --git a/modules/swap/module.py b/modules/swap/module.py
index b03140d..ffedbab 100644
--- a/modules/swap/module.py
+++ b/modules/swap/module.py
@@ -17,7 +17,8 @@ class SwapModule(AbstractModule):
             "Get swap location": self._get_swap_location,
             "Get swap size": self._get_swap_size,
             "Show swapiness": self._show_swapiness,
-            "Adjust temp. swapiness": self._adjust_swapiness_temp
+            "Adjust temp. swapiness": self._adjust_swapiness_temp,
+            "Check fstab for entry": self._check_fstab_entry
         }
         menu = [
             {
@@ -82,14 +83,18 @@ class SwapModule(AbstractModule):
 
     def _make_swap_persistent(self):
         swap_location = self._get_swap_location()
+        persistence_entry = self._check_fstab_entry()
         if swap_location is None:
             print("Swap file doesn't exist!")
             return
         backup_fstab = "sudo cp /etc/fstab /etc/fstab.bak"
         enable_persistence = "echo '{} none swap sw 0 0' | sudo tee -a /etc/fstab".format(swap_location)
-        subprocess.call(backup_fstab, shell=True)
-        subprocess.call(enable_persistence, shell=True)
-        print("Swap is now persistent!")
+        if persistence_entry is True:
+            print("Swap is already persistent!")
+        else:
+            subprocess.call(backup_fstab, shell=True)
+            subprocess.call(enable_persistence, shell=True)
+            print("Swap is now persistent!")
 
     def _show_swapiness(self):
         get_swapiness = "cat /proc/sys/vm/swappiness"
@@ -127,3 +132,15 @@ class SwapModule(AbstractModule):
         if not output_swapon:
             print("Swap deleted!")
             print(output_free.strip())
+
+    def _check_fstab_entry(self):
+        swap_location = self._get_swap_location()
+        fstab_entry = "{} none swap sw 0 0\n".format(swap_location)
+        with open("/etc/fstab", "r") as fstab_file:
+            line = fstab_file.readlines()[-1]
+            if line != fstab_entry:
+                print("No entry in /etc/fstab")
+                return False
+            else:
+                print("fstab entry:", line.strip())
+                return True