From 68892f94aee1400cebbe9f7360cc4a5804c3c2b1 Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Tue, 25 May 2021 17:40:54 +0200
Subject: [PATCH 1/2] loginctl: kill calling user when invoked with empty
 string

A suggested by: #19711
---
 src/login/loginctl.c | 24 ++++++++++++++++++------
 1 file changed, 18 insertions(+), 6 deletions(-)

diff --git a/src/login/loginctl.c b/src/login/loginctl.c
index 7a2b13e442..cbb6518f4d 100644
--- a/src/login/loginctl.c
+++ b/src/login/loginctl.c
@@ -1086,9 +1086,15 @@ static int terminate_user(int argc, char *argv[], void *userdata) {
         for (int i = 1; i < argc; i++) {
                 uid_t uid;
 
-                r = get_user_creds((const char**) (argv+i), &uid, NULL, NULL, NULL, 0);
-                if (r < 0)
-                        return log_error_errno(r, "Failed to look up user %s: %m", argv[i]);
+                if (isempty(argv[i]))
+                        uid = getuid();
+                else {
+                        const char *u = argv[i];
+
+                        r = get_user_creds(&u, &uid, NULL, NULL, NULL, 0);
+                        if (r < 0)
+                                return log_error_errno(r, "Failed to look up user %s: %m", argv[i]);
+                }
 
                 r = bus_call_method(bus, bus_login_mgr, "TerminateUser", &error, NULL, "u", (uint32_t) uid);
                 if (r < 0)
@@ -1114,9 +1120,15 @@ static int kill_user(int argc, char *argv[], void *userdata) {
         for (int i = 1; i < argc; i++) {
                 uid_t uid;
 
-                r = get_user_creds((const char**) (argv+i), &uid, NULL, NULL, NULL, 0);
-                if (r < 0)
-                        return log_error_errno(r, "Failed to look up user %s: %m", argv[i]);
+                if (isempty(argv[i]))
+                        uid = getuid();
+                else {
+                        const char *u = argv[i];
+
+                        r = get_user_creds(&u, &uid, NULL, NULL, NULL, 0);
+                        if (r < 0)
+                                return log_error_errno(r, "Failed to look up user %s: %m", argv[i]);
+                }
 
                 r = bus_call_method(
                         bus,

From 9f48b4e40ea69b90f61ac2e35b3b272f9cc31674 Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Tue, 25 May 2021 17:42:34 +0200
Subject: [PATCH 2/2] man: documet that loginctl
 {terminate|kill}-{session|user} take the empty string, optionally

Fixes: #19711
---
 man/loginctl.xml | 26 +++++++++++++-------------
 1 file changed, 13 insertions(+), 13 deletions(-)

diff --git a/man/loginctl.xml b/man/loginctl.xml
index 56a86e56ef..bef3be71c9 100644
--- a/man/loginctl.xml
+++ b/man/loginctl.xml
@@ -113,18 +113,18 @@
       <varlistentry>
         <term><command>terminate-session</command> <replaceable>ID</replaceable>…</term>
 
-        <listitem><para>Terminates a session. This kills all processes
-        of the session and deallocates all resources attached to the
-        session. </para></listitem>
+        <listitem><para>Terminates a session. This kills all processes of the session and deallocates all
+        resources attached to the session. If the argument is specified as empty string the session invoking
+        the command is terminated.</para></listitem>
       </varlistentry>
 
       <varlistentry>
         <term><command>kill-session</command> <replaceable>ID</replaceable>…</term>
 
-        <listitem><para>Send a signal to one or more processes of the
-        session. Use <option>--kill-who=</option> to select which
-        process to kill. Use <option>--signal=</option> to select the
-        signal to send.</para></listitem>
+        <listitem><para>Send a signal to one or more processes of the session. Use
+        <option>--kill-who=</option> to select which process to kill. Use <option>--signal=</option> to
+        select the signal to send. If the argument is specified as empty string the signal is sent to the
+        session invoking the command.</para></listitem>
       </varlistentry>
     </variablelist></refsect2>
 
@@ -184,17 +184,17 @@
       <varlistentry>
         <term><command>terminate-user</command> <replaceable>USER</replaceable>…</term>
 
-        <listitem><para>Terminates all sessions of a user. This kills
-        all processes of all sessions of the user and deallocates all
-        runtime resources attached to the user.</para></listitem>
+        <listitem><para>Terminates all sessions of a user. This kills all processes of all sessions of the
+        user and deallocates all runtime resources attached to the user. If the argument is specified as
+        empty string the sessions of the user invoking the command are terminated.</para></listitem>
       </varlistentry>
 
       <varlistentry>
         <term><command>kill-user</command> <replaceable>USER</replaceable>…</term>
 
-        <listitem><para>Send a signal to all processes of a user. Use
-        <option>--signal=</option> to select the signal to send.
-        </para></listitem>
+        <listitem><para>Send a signal to all processes of a user. Use <option>--signal=</option> to select
+        the signal to send. If the argument is specified as empty string the signal is sent to the sessions
+        of the user invoking the command.</para></listitem>
       </varlistentry>
     </variablelist></refsect2>