From d424adce45d593d41e52294bd8f32fd33c625498 Mon Sep 17 00:00:00 2001

From: =?UTF-8?q?Zbigniew=20J=C4=99drzejewski-Szmek?= <zbyszek@in.waw.pl>

Date: Mon, 7 Mar 2022 18:54:50 +0100

Subject: [PATCH] basic: add new variable $SYSTEMD_OS_RELEASE to override

 location of os-release

The test for the variable is added in test-systemctl-enable because there we

can do it almost for free, and the variable is most likely to be used with

'systemctl enable --root' anyway.

(cherry picked from commit df78419d107662dd49892d76a745c294d7031d66)

Related: #2082131

---

 docs/ENVIRONMENT.md           |  5 +++++

 src/basic/os-util.c           | 16 +++++++++++-----

 test/test-systemctl-enable.sh | 12 ++++++++++--

 3 files changed, 26 insertions(+), 7 deletions(-)

diff --git a/docs/ENVIRONMENT.md b/docs/ENVIRONMENT.md

index 71d6c55010..5e9548449c 100644

--- a/docs/ENVIRONMENT.md

+++ b/docs/ENVIRONMENT.md

@@ -43,6 +43,11 @@ All tools:

   debugging, in order to test generators and other code against specific kernel

   command lines.

+* `$SYSTEMD_OS_RELEASE` — if set, use this path instead of `/etc/os-release` or

+  `/usr/lib/os-release`. When operating under some root (e.g. `systemctl

+  --root=…`), the path is taken relative to the outside root. Only useful for

+  debugging.

+

 * `$SYSTEMD_FSTAB` — if set, use this path instead of `/etc/fstab`. Only useful

   for debugging.

diff --git a/src/basic/os-util.c b/src/basic/os-util.c

index a6e4d09473..38b2179e48 100644

--- a/src/basic/os-util.c

+++ b/src/basic/os-util.c

@@ -170,13 +170,19 @@ int open_extension_release(const char *root, const char *extension, char **ret_p

                         }

                 }

         } else {

-                FOREACH_STRING(p, "/etc/os-release", "/usr/lib/os-release") {

-                        r = chase_symlinks(p, root, CHASE_PREFIX_ROOT,

+                const char *var = secure_getenv("SYSTEMD_OS_RELEASE");

+                if (var)

+                        r = chase_symlinks(var, root, 0,

                                            ret_path ? &q : NULL,

                                            ret_fd ? &fd : NULL);

-                        if (r != -ENOENT)

-                                break;

-                }

+                else

+                        FOREACH_STRING(path, "/etc/os-release", "/usr/lib/os-release") {

+                                r = chase_symlinks(path, root, CHASE_PREFIX_ROOT,

+                                                   ret_path ? &q : NULL,

+                                                   ret_fd ? &fd : NULL);

+                                if (r != -ENOENT)

+                                        break;

+                        }

         }

         if (r < 0)

                 return r;

diff --git a/test/test-systemctl-enable.sh b/test/test-systemctl-enable.sh

index 30ba6532e7..769341129c 100644

--- a/test/test-systemctl-enable.sh

+++ b/test/test-systemctl-enable.sh

@@ -518,6 +518,14 @@ check_alias z 'z' && { echo "Expected failure because %z is not known" >&2; exit

 # FIXME: if there's an invalid Alias=, we shouldn't preach about empty [Install]

-exit 0  # yes, this is needed because the last test above fails

-

 # TODO: repeat the tests above for presets

+

+: -------SYSTEMD_OS_RELEASE relative to root------------------

+# check that os-release overwriting works as expected with root

+test -e "$root/etc/os-release"

+

+cat >"$root/etc/os-release2" <

+ID='the-id2'

+EOF

+

+SYSTEMD_OS_RELEASE="$root/etc/os-release2" check_alias o 'the-id2'