guix-install.sh: Run the uninstall even if already partially done

Removing users, groups or Systemd units fails if they are already absent,
causing the uninstall script to exit. The goal here is to make the uninstall
always run entirely, whatever parts are already done.

* etc/guix-install.sh (sys_delete_build_user): Test if users and groups exist
before deleting them.
(sys_delete_guix_daemon): Test if /etc/systemd/system/guix-daemon.service file
exists before removing the matching Systemd unit.

Change-Id: Ibffb1f1b39de675542fb8057af21ecaea1b53d4c
Signed-off-by: Ludovic Courtès <ludo@gnu.org>

1 files changed, 14 insertions, 8 deletions

diff --git a/etc/guix-install.sh b/etc/guix-install.sh
index 7fb5ac63c5d..f07b2741bb9 100755
--- a/etc/guix-install.sh
+++ b/etc/guix-install.sh
@@ -451,11 +451,15 @@ sys_create_build_user()
 sys_delete_build_user()
 {
     for i in $(seq -w 1 10); do
-        userdel -f guixbuilder${i}
+        if id -u "guixbuilder${i}" &>/dev/null; then
+            userdel -f guixbuilder${i}
+        fi
     done
 
     _msg "${INF}delete group guixbuild"
-    groupdel -f guixbuild
+    if getent group guixbuild &>/dev/null; then
+        groupdel -f guixbuild
+    fi
 }
 
 sys_enable_guix_daemon()
@@ -569,12 +573,14 @@ sys_delete_guix_daemon()
             ;;
 
         systemd)
-            _msg "${INF}disabling guix-daemon"
-            systemctl disable guix-daemon
-            _msg "${INF}stopping guix-daemon"
-            systemctl stop guix-daemon
-            _msg "${INF}removing guix-daemon"
-            rm -f /etc/systemd/system/guix-daemon.service
+            if [ -f /etc/systemd/system/guix-daemon.service ]; then
+                _msg "${INF}disabling guix-daemon"
+                systemctl disable guix-daemon
+                _msg "${INF}stopping guix-daemon"
+                systemctl stop guix-daemon
+                _msg "${INF}removing guix-daemon"
+                rm -f /etc/systemd/system/guix-daemon.service
+            fi
 
             if [ -f /etc/systemd/system/gnu-store.mount ]; then
                 _msg "${INF}disabling gnu-store.mount"