From 13c099caa9ae0389423c403152952c3c548fd146 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Zbigniew=20J=C4=99drzejewski-Szmek?= <zbyszek@in.waw.pl>
Date: Thu, 17 Mar 2022 16:02:10 +0100
Subject: [PATCH] shared/install: fix handling of a linked unit file

When we have a symlink that goes outside of our search path, we should just
ignore the target file name. But we were verifying it, and rejecting in
the case where a symlink was created manually.

(cherry picked from commit 48eadb9d9b66f302cda09cdf6d35fead31aaa968)

Related: #2082131
---
 src/shared/install.c          |  4 +++-
 test/test-systemctl-enable.sh | 12 ++++++++----
 2 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/src/shared/install.c b/src/shared/install.c
index b33f7d4bc1..d6951b805d 100644
--- a/src/shared/install.c
+++ b/src/shared/install.c
@@ -1609,7 +1609,9 @@ static int install_info_traverse(
                                 return -ELOOP;
                 }
 
-                r = install_info_follow(ctx, i, lp, flags, false);
+                r = install_info_follow(ctx, i, lp, flags,
+                                        /* If linked, don't look at the target name */
+                                        /* ignore_different_name= */ i->type == UNIT_FILE_TYPE_LINKED);
                 if (r == -EXDEV) {
                         _cleanup_free_ char *buffer = NULL;
                         const char *bn;
diff --git a/test/test-systemctl-enable.sh b/test/test-systemctl-enable.sh
index 9463433c5b..45f3513de3 100644
--- a/test/test-systemctl-enable.sh
+++ b/test/test-systemctl-enable.sh
@@ -216,12 +216,16 @@ cat >"$root/link3.suffix" <<EOF
 WantedBy=services.target
 EOF
 
+# We wouldn't create such a link ourselves, but it should accept it when present.
 ln -s "/link3.suffix" "$root/etc/systemd/system/link3.service"
 
-# SYSTEMD_LOG_LEVEL=debug SYSTEMD_LOG_LOCATION=1 "$systemctl" --root="$root" enable 'link3.service'
-# islink "$root/etc/systemd/system/link3.service" "/link3.suffix"
-# islink "$root/etc/systemd/system/services.target.wants/link3.service" "../link3.service"
-# unit_file_load_or_readlink() needs to be fixed to not follow links
+SYSTEMD_LOG_LEVEL=debug SYSTEMD_LOG_LOCATION=1 "$systemctl" --root="$root" enable 'link3.service'
+islink "$root/etc/systemd/system/link3.service" "/link3.suffix"
+islink "$root/etc/systemd/system/services.target.wants/link3.service" "../link3.service"
+
+SYSTEMD_LOG_LEVEL=debug SYSTEMD_LOG_LOCATION=1 "$systemctl" --root="$root" disable 'link3.service'
+test ! -h "$root/etc/systemd/system/link3.service"
+test ! -h "$root/etc/systemd/system/services.target.wants/link3.service"
 
 : -------enable on masked-------------------------------------
 ln -s "/dev/null" "$root/etc/systemd/system/masked.service"