core: extend KillUnit() to return error when no unit was killed

man/systemctl.xml

@@ -294,6 +294,17 @@
 
       </varlistentry>
 
+      <varlistentry>
+        <term><option>--fail</option></term>
+
+        <listitem>
+          <para>Shorthand for <option>--job-mode=</option>fail.</para>
+          <para>When used with the <command>kill</command> command,
+          if no units were killed, the operation results in an error.
+          </para>
+        </listitem>
+      </varlistentry>
+
       <varlistentry>
         <term><option>-i</option></term>
         <term><option>--ignore-inhibitors</option></term>

src/core/kill.c

@@ -60,7 +60,10 @@ DEFINE_STRING_TABLE_LOOKUP(kill_mode, KillMode);
 static const char* const kill_who_table[_KILL_WHO_MAX] = {
         [KILL_MAIN] = "main",
         [KILL_CONTROL] = "control",
-        [KILL_ALL] = "all"
+        [KILL_ALL] = "all",
+        [KILL_MAIN_FAIL] = "main-fail",
+        [KILL_CONTROL_FAIL] = "control-fail",
+        [KILL_ALL_FAIL] = "all-fail"
 };
 
 DEFINE_STRING_TABLE_LOOKUP(kill_who, KillWho);

src/core/kill.h

@@ -50,6 +50,9 @@ typedef enum KillWho {
         KILL_MAIN,
         KILL_CONTROL,
         KILL_ALL,
+        KILL_MAIN_FAIL,
+        KILL_CONTROL_FAIL,
+        KILL_ALL_FAIL,
         _KILL_WHO_MAX,
         _KILL_WHO_INVALID = -1
 } KillWho;

src/core/unit.c

@@ -3064,32 +3064,39 @@ int unit_kill_common(
                 sd_bus_error *error) {
 
         int r = 0;
+        bool killed = false;
 
-        if (who == KILL_MAIN) {
+        if (IN_SET(who, KILL_MAIN, KILL_MAIN_FAIL)) {
                 if (main_pid < 0)
                         return sd_bus_error_setf(error, BUS_ERROR_NO_SUCH_PROCESS, "%s units have no main processes", unit_type_to_string(u->type));
                 else if (main_pid == 0)
                         return sd_bus_error_set_const(error, BUS_ERROR_NO_SUCH_PROCESS, "No main process to kill");
         }
 
-        if (who == KILL_CONTROL) {
+        if (IN_SET(who, KILL_CONTROL, KILL_CONTROL_FAIL)) {
                 if (control_pid < 0)
                         return sd_bus_error_setf(error, BUS_ERROR_NO_SUCH_PROCESS, "%s units have no control processes", unit_type_to_string(u->type));
                 else if (control_pid == 0)
                         return sd_bus_error_set_const(error, BUS_ERROR_NO_SUCH_PROCESS, "No control process to kill");
         }
 
-        if (who == KILL_CONTROL || who == KILL_ALL)
-                if (control_pid > 0)
+        if (IN_SET(who, KILL_CONTROL, KILL_CONTROL_FAIL, KILL_ALL, KILL_ALL_FAIL))
+                if (control_pid > 0) {
                         if (kill(control_pid, signo) < 0)
                                 r = -errno;
+                        else
+                                killed = true;
+                }
 
-        if (who == KILL_MAIN || who == KILL_ALL)
-                if (main_pid > 0)
+        if (IN_SET(who, KILL_MAIN, KILL_MAIN_FAIL, KILL_ALL, KILL_ALL_FAIL))
+                if (main_pid > 0) {
                         if (kill(main_pid, signo) < 0)
                                 r = -errno;
+                        else
+                                killed = true;
+                }
 
-        if (who == KILL_ALL && u->cgroup_path) {
+        if (IN_SET(who, KILL_ALL, KILL_ALL_FAIL) && u->cgroup_path) {
                 _cleanup_set_free_ Set *pid_set = NULL;
                 int q;
 
@@ -3101,8 +3108,13 @@ int unit_kill_common(
                 q = cg_kill_recursive(SYSTEMD_CGROUP_CONTROLLER, u->cgroup_path, signo, false, false, false, pid_set);
                 if (q < 0 && q != -EAGAIN && q != -ESRCH && q != -ENOENT)
                         r = q;
+                else
+                        killed = true;
         }
 
+        if (r == 0 && !killed && IN_SET(who, KILL_ALL_FAIL, KILL_CONTROL_FAIL, KILL_ALL_FAIL))
+                return -ESRCH;
+
         return r;
 }
 

src/systemctl/systemctl.c

@@ -3107,7 +3107,7 @@ static int check_unit_failed(sd_bus *bus, char **args) {
 
 static int kill_unit(sd_bus *bus, char **args) {
         _cleanup_strv_free_ char **names = NULL;
-        char **name;
+        char *kill_who = NULL, **name;
         int r, q;
 
         assert(bus);
@@ -3118,6 +3118,10 @@ static int kill_unit(sd_bus *bus, char **args) {
         if (!arg_kill_who)
                 arg_kill_who = "all";
 
+        /* --fail was specified */
+        if (streq(arg_job_mode, "fail"))
+                kill_who = strjoina(arg_kill_who, "-fail", NULL);
+
         r = expand_names(bus, args + 1, NULL, &names);
         if (r < 0)
                 log_error_errno(r, "Failed to expand names: %m");
@@ -3133,7 +3137,7 @@ static int kill_unit(sd_bus *bus, char **args) {
                                 "KillUnit",
                                 &error,
                                 NULL,
-                                "ssi", *names, arg_kill_who, arg_signal);
+                                "ssi", *names, kill_who ? kill_who : arg_kill_who, arg_signal);
                 if (q < 0) {
                         log_error("Failed to kill unit %s: %s", *names, bus_error_message(&error, q));
                         if (r == 0)