From d501347a8ae23a2fb312949c588c7565eb54b2da Mon Sep 17 00:00:00 2001
From: Paul Eggert  <eggert@cs.ucla.edu>	
Date: Mon, 18 Mar 2024 09:10:31 +0800
Subject: [PATCH] fix core dump if --enable-systemd

From gnulib upstream commits:
* 1e6a26f9312bb47e070f94b17b14dc1a6ffbb74f ("readutmp: fix core dump if --enable-systemd")
Problem reported by Thorsten Kukuk <https://bugs.gnu.org/65617>.
lib/readutmp.c (read_utmp_from_systemd):
Don’t assume session_ptr != NULL if num_sessions == 0.
In practice it can be null, and the man page OKs this behavior.

* 3af1d7b0ce3a8e3ae565e7cea10cee6fd7cb8109 ("readutmp: Fix memory leak introduced by last commit.")
lib/readutmp.c (read_utmp_from_systemd): If num_sessions == 0 and
sessions != NULL, do call free (sessions).
---
 lib/readutmp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/readutmp.c b/lib/readutmp.c
index 0173b7e..ec09feb 100644
--- a/lib/readutmp.c
+++ b/lib/readutmp.c
@@ -795,7 +795,7 @@ read_utmp_from_systemd (idx_t *n_entries, STRUCT_UTMP **utmp_buf, int options)
     {
       char **sessions;
       int num_sessions = sd_get_sessions (&sessions);
-      if (num_sessions >= 0)
+      if (num_sessions >= 0 && sessions != NULL)
         {
           char **session_ptr;
           for (session_ptr = sessions; *session_ptr != NULL; session_ptr++)
-- 
2.41.0

