From: MertsA <mertsa@fb.com>
Date: Wed, 11 Aug 2021 03:54:50 +0000 (-0700)
Subject: Get rid of dangling setutxent()
X-Git-Tag: v250-rc1~844
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=bbd239f67a683fe63ee3698896fa503ff25031ed;p=thirdparty%2Fsystemd.git

Get rid of dangling setutxent()

utmp_wall() and utmp_put_dead_process() called setutxent() directly instead of the stub in utmp-wtmp.h and never called endutxent(). This would leave /run/utmp left open by PID 1 or journald. This can be reproduced by e.g. lsof /run/utmp and systemd-cat -p 0 echo test. For utmp_put_dead_process() it would only leave it open if it returned early before calling write_utmp_wtmp()
---

diff --git a/src/shared/utmp-wtmp.c b/src/shared/utmp-wtmp.c
index b31cdd679ba..fee5bd1c95f 100644
--- a/src/shared/utmp-wtmp.c
+++ b/src/shared/utmp-wtmp.c
@@ -215,13 +215,14 @@ int utmp_put_init_process(const char *id, pid_t pid, pid_t sid, const char *line
 }
 
 int utmp_put_dead_process(const char *id, pid_t pid, int code, int status) {
+        _cleanup_(utxent_cleanup) bool utmpx = false;
         struct utmpx lookup = {
                 .ut_type = INIT_PROCESS /* looks for DEAD_PROCESS, LOGIN_PROCESS, USER_PROCESS, too */
         }, store, store_wtmp, *found;
 
         assert(id);
 
-        setutxent();
+        utmpx = utxent_start();
 
         /* Copy the whole string if it fits, or just the suffix without the terminating NUL. */
         copy_suffix(store.ut_id, sizeof(store.ut_id), id);
@@ -339,6 +340,7 @@ int utmp_wall(
         bool (*match_tty)(const char *tty, void *userdata),
         void *userdata) {
 
+        _cleanup_(utxent_cleanup) bool utmpx = false;
         _cleanup_free_ char *text = NULL, *hn = NULL, *un = NULL, *stdin_tty = NULL;
         struct utmpx *u;
         int r;
@@ -367,7 +369,7 @@ int utmp_wall(
                      message) < 0)
                 return -ENOMEM;
 
-        setutxent();
+        utmpx = utxent_start();
 
         r = 0;