From dcde1e903ae57cb7ad52e3a5716ce28bb91fdf63 Mon Sep 17 00:00:00 2001
From: Matteo Croce <teknoraver@meta.com>
Date: Sun, 16 Mar 2025 02:48:29 +0100
Subject: [PATCH] match glibc in ConditionVersion

Extend ConditionVersion= to allow matching against glibc version,
as proposed in https://github.com/systemd/systemd/pull/36468#issuecomment-2674600909
---
 man/systemd.unit.xml                 |  8 ++++----
 src/shared/condition.c               |  4 ++++
 src/test/test-condition.c            | 30 ++++++++++++++++++++++++++++
 test/test-execute/exec-basic.service |  5 +++++
 4 files changed, 43 insertions(+), 4 deletions(-)

diff --git a/man/systemd.unit.xml b/man/systemd.unit.xml
index 5be9225a587..0bc3668f4cb 100644
--- a/man/systemd.unit.xml
+++ b/man/systemd.unit.xml
@@ -1487,10 +1487,10 @@
           <listitem><para><varname>ConditionVersion=</varname> may be used to check whether a software
           version matches a certain expression, or if prefixed with the exclamation mark, does not match.
           The first argument is the software whose version has to be checked. Currently
-          <literal>kernel</literal> and <literal>systemd</literal> are supported. If this argument is
-          omitted, <literal>kernel</literal> is implied. The second argument must be a list
-          of (potentially quoted) expressions. Each expression starts with one of <literal>=</literal> or
-          <literal>!=</literal> for string comparisons, <literal>&lt;</literal>, <literal>&lt;=</literal>,
+          <literal>kernel</literal>, <literal>systemd</literal> and <literal>glibc</literal> are supported.
+          If this argument is omitted, <literal>kernel</literal> is implied. The second argument must be a
+          list of (potentially quoted) expressions. Each expression starts with one of <literal>=</literal>
+          or <literal>!=</literal> for string comparisons, <literal>&lt;</literal>, <literal>&lt;=</literal>,
           <literal>==</literal>, <literal>&lt;&gt;</literal>, <literal>&gt;=</literal>,
           <literal>&gt;</literal> for version comparisons, or <literal>$=</literal>, <literal>!$=</literal>
           for a shell-style glob match. If no operator is specified, <literal>$=</literal> is implied.</para>
diff --git a/src/shared/condition.c b/src/shared/condition.c
index b65d64d300d..e6481c46417 100644
--- a/src/shared/condition.c
+++ b/src/shared/condition.c
@@ -4,6 +4,7 @@
 #include <errno.h>
 #include <fcntl.h>
 #include <fnmatch.h>
+#include <gnu/libc-version.h>
 #include <limits.h>
 #include <stdlib.h>
 #include <sys/stat.h>
@@ -258,6 +259,9 @@ static int condition_test_version(Condition *c, char **env) {
         if (streq(word, "systemd"))
                 return condition_test_version_cmp(p, STRINGIFY(PROJECT_VERSION));
 
+        if (streq(word, "glibc"))
+                return condition_test_version_cmp(p, gnu_get_libc_version());
+
         /* if no predicate has been set, default to "kernel" and use the whole parameter as condition */
         if (!streq(word, "kernel"))
                 p = c->parameter;
diff --git a/src/test/test-condition.c b/src/test/test-condition.c
index a6132f1132b..b02f4cce6da 100644
--- a/src/test/test-condition.c
+++ b/src/test/test-condition.c
@@ -1,5 +1,6 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
+#include <gnu/libc-version.h>
 #include <stdio.h>
 #include <sys/types.h>
 #include <sys/utsname.h>
@@ -676,6 +677,35 @@ TEST(condition_test_version) {
         ASSERT_NOT_NULL((condition = condition_new(CONDITION_VERSION, v, false, false)));
         ASSERT_OK_ZERO(condition_test(condition, environ));
         condition_free(condition);
+
+        /* Test glibc version */
+        ASSERT_NOT_NULL((condition = condition_new(CONDITION_VERSION, "glibc > 1", false, false)));
+        ASSERT_OK_POSITIVE(condition_test(condition, environ));
+        condition_free(condition);
+
+        ASSERT_NOT_NULL((condition = condition_new(CONDITION_VERSION, "glibc < 2", false, false)));
+        ASSERT_OK_ZERO(condition_test(condition, environ));
+        condition_free(condition);
+
+        ASSERT_NOT_NULL((condition = condition_new(CONDITION_VERSION, "glibc < 9999", false, false)));
+        ASSERT_OK_POSITIVE(condition_test(condition, environ));
+        condition_free(condition);
+
+        ASSERT_NOT_NULL((condition = condition_new(CONDITION_VERSION, "glibc > 9999", false, false)));
+        ASSERT_OK_ZERO(condition_test(condition, environ));
+        condition_free(condition);
+
+        v = strjoina("glibc = ", gnu_get_libc_version());
+
+        ASSERT_NOT_NULL((condition = condition_new(CONDITION_VERSION, v, false, false)));
+        ASSERT_OK_POSITIVE(condition_test(condition, environ));
+        condition_free(condition);
+
+        v = strjoina("glibc != ", gnu_get_libc_version());
+
+        ASSERT_NOT_NULL((condition = condition_new(CONDITION_VERSION, v, false, false)));
+        ASSERT_OK_ZERO(condition_test(condition, environ));
+        condition_free(condition);
 }
 
 TEST(condition_test_credential) {
diff --git a/test/test-execute/exec-basic.service b/test/test-execute/exec-basic.service
index 1fb300dc152..c29d46c2dfb 100644
--- a/test/test-execute/exec-basic.service
+++ b/test/test-execute/exec-basic.service
@@ -21,6 +21,11 @@ ConditionVersion=systemd ">=20" "<=9000" "!=14"
 ConditionVersion=systemd " >= 20" " <= 9000 " "!= 14"
 ConditionVersion=systemd " >= 20" " * "
 
+ConditionVersion=glibc ">=2"
+ConditionVersion=glibc ">=2" "<=9000" "!=1"
+ConditionVersion=glibc " >= 2" " <= 9000 " "!= 1"
+ConditionVersion=glibc " >= 2" " * "
+
 [Service]
 ExecStart=touch /tmp/a ; /bin/sh -c 'touch /tmp/b' ; touch /tmp/c
 ExecStart=test -f /tmp/a
-- 
2.47.3