base/SOURCES/0609-core-don-t-choke-if-a-unit-another-unit-triggers-van.patch

From d7b2f6efd02375af4cf043ef9db6d316b65d4779 Mon Sep 17 00:00:00 2001
From: Jan Synacek <jsynacek@redhat.com>
Date: Fri, 16 Feb 2018 09:56:50 +0100
Subject: [PATCH] core: don't choke if a unit another unit triggers vanishes
 during reload

Fixes: #1981

(cherry picked from e903182e5b0daa941de47a9c08c824106cec7fe0)
Resolves: #1545676
---
 src/core/automount.c | 25 +++++++++++++++++++++----
 src/core/path.c      | 18 +++++++++++++++---
 src/core/timer.c     | 30 ++++++++++++++++++++++++++----
 3 files changed, 62 insertions(+), 11 deletions(-)

diff --git a/src/core/automount.c b/src/core/automount.c
index 182ba5240..679fe071e 100644
--- a/src/core/automount.c
+++ b/src/core/automount.c
@@ -715,6 +715,7 @@ static int automount_start_expire(Automount *a) {
 static void automount_enter_running(Automount *a) {
         _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
         struct stat st;
+        Unit *trigger;
         int r;
 
         assert(a);
@@ -753,8 +754,13 @@ static void automount_enter_running(Automount *a) {
                 return;
         }
 
-        r = manager_add_job(UNIT(a)->manager, JOB_START, UNIT_TRIGGER(UNIT(a)),
-                        JOB_REPLACE, true, &error, NULL);
+        trigger = UNIT_TRIGGER(UNIT(a));
+        if (!trigger) {
+                log_unit_error(UNIT(a)->id, "Unit to trigger vanished.");
+                goto fail;
+        }
+
+        r = manager_add_job(UNIT(a)->manager, JOB_START, trigger, JOB_REPLACE, true, &error, NULL);
         if (r < 0) {
                 log_unit_warning(UNIT(a)->id,
                                 "%s failed to queue mount startup job: %s",
@@ -775,6 +781,7 @@ fail:
 
 static int automount_start(Unit *u) {
         Automount *a = AUTOMOUNT(u);
+        Unit *trigger;
 
         assert(a);
         assert(a->state == AUTOMOUNT_DEAD || a->state == AUTOMOUNT_FAILED);
@@ -786,8 +793,11 @@ static int automount_start(Unit *u) {
                 return -EEXIST;
         }
 
-        if (UNIT_TRIGGER(u)->load_state != UNIT_LOADED)
+        trigger = UNIT_TRIGGER(u);
+        if (!trigger || trigger->load_state != UNIT_LOADED) {
+                log_unit_error(u->id, "Refusing to start, unit to trigger not loaded.");
                 return -ENOENT;
+        }
 
         a->result = AUTOMOUNT_SUCCESS;
         automount_enter_waiting(a);
@@ -936,6 +946,7 @@ static int automount_dispatch_io(sd_event_source *s, int fd, uint32_t events, vo
         _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
         union autofs_v5_packet_union packet;
         Automount *a = AUTOMOUNT(userdata);
+        Unit *trigger;
         ssize_t l;
         int r;
 
@@ -1002,7 +1013,13 @@ static int automount_dispatch_io(sd_event_source *s, int fd, uint32_t events, vo
                         log_unit_error_errno(UNIT(a)->id, r, "Failed to remember token: %m");
                         goto fail;
                 }
-                r = manager_add_job(UNIT(a)->manager, JOB_STOP, UNIT_TRIGGER(UNIT(a)), JOB_REPLACE, true, &error, NULL);
+
+                trigger = UNIT_TRIGGER(UNIT(a));
+                if (!trigger) {
+                        log_unit_error(UNIT(a)->id, "Unit to trigger vanished.");
+                        goto fail;
+                }
+                r = manager_add_job(UNIT(a)->manager, JOB_STOP, trigger, JOB_REPLACE, true, &error, NULL);
                 if (r < 0) {
                         log_unit_warning(UNIT(a)->id,
                                          "%s failed to queue umount startup job: %s",
diff --git a/src/core/path.c b/src/core/path.c
index 51e36fa8b..0533bb4e2 100644
--- a/src/core/path.c
+++ b/src/core/path.c
@@ -475,6 +475,7 @@ static void path_enter_dead(Path *p, PathResult f) {
 
 static void path_enter_running(Path *p) {
         _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
+        Unit *trigger;
         int r;
 
         assert(p);
@@ -483,8 +484,14 @@ static void path_enter_running(Path *p) {
         if (unit_stop_pending(UNIT(p)))
                 return;
 
-        r = manager_add_job(UNIT(p)->manager, JOB_START, UNIT_TRIGGER(UNIT(p)),
-                            JOB_REPLACE, true, &error, NULL);
+        trigger = UNIT_TRIGGER(UNIT(p));
+        if (!trigger) {
+                log_unit_error(UNIT(p)->id, "Unit to trigger vanished.");
+                path_enter_dead(p, TIMER_FAILURE_RESOURCES);
+                return;
+        }
+
+        r = manager_add_job(UNIT(p)->manager, JOB_START, trigger, JOB_REPLACE, true, &error, NULL);
         if (r < 0)
                 goto fail;
 
@@ -566,12 +573,17 @@ static void path_mkdir(Path *p) {
 
 static int path_start(Unit *u) {
         Path *p = PATH(u);
+        Unit *trigger;
 
         assert(p);
         assert(p->state == PATH_DEAD || p->state == PATH_FAILED);
 
-        if (UNIT_TRIGGER(u)->load_state != UNIT_LOADED)
+
+        trigger = UNIT_TRIGGER(u);
+        if (!trigger || trigger->load_state != UNIT_LOADED) {
+                log_unit_error(u->id, "Refusing to start, unit to trigger not loaded.");
                 return -ENOENT;
+        }
 
         path_mkdir(p);
 
diff --git a/src/core/timer.c b/src/core/timer.c
index f318dc6f4..91d8db67e 100644
--- a/src/core/timer.c
+++ b/src/core/timer.c
@@ -343,8 +343,18 @@ static void timer_enter_waiting(Timer *t, bool initial) {
         usec_t ts_realtime, ts_monotonic;
         usec_t base = 0;
         TimerValue *v;
+        Unit *trigger;
         int r;
 
+        assert(t);
+
+        trigger = UNIT_TRIGGER(UNIT(t));
+        if (!trigger) {
+                log_unit_error(UNIT(t)->id, "Unit to trigger vanished.");
+                timer_enter_dead(t, TIMER_FAILURE_RESOURCES);
+                return;
+        }
+
         /* If we shall wake the system we use the boottime clock
          * rather than the monotonic clock. */
 
@@ -399,7 +409,7 @@ static void timer_enter_waiting(Timer *t, bool initial) {
 
                         case TIMER_UNIT_ACTIVE:
 
-                                base = UNIT_TRIGGER(UNIT(t))->inactive_exit_timestamp.monotonic;
+                                base = trigger->inactive_exit_timestamp.monotonic;
 
                                 if (base <= 0)
                                         base = t->last_trigger.monotonic;
@@ -523,6 +533,7 @@ fail:
 
 static void timer_enter_running(Timer *t) {
         _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
+        Unit *trigger;
         int r;
 
         assert(t);
@@ -531,8 +542,15 @@ static void timer_enter_running(Timer *t) {
         if (unit_stop_pending(UNIT(t)))
                 return;
 
-        r = manager_add_job(UNIT(t)->manager, JOB_START, UNIT_TRIGGER(UNIT(t)),
-                            JOB_REPLACE, true, &error, NULL);
+
+        trigger = UNIT_TRIGGER(UNIT(t));
+        if (!trigger) {
+                log_unit_error(UNIT(t)->id, "Unit to trigger vanished.");
+                timer_enter_dead(t, TIMER_FAILURE_RESOURCES);
+                return;
+        }
+
+        r = manager_add_job(UNIT(t)->manager, JOB_START, trigger, JOB_REPLACE, true, &error, NULL);
         if (r < 0)
                 goto fail;
 
@@ -554,12 +572,16 @@ fail:
 static int timer_start(Unit *u) {
         Timer *t = TIMER(u);
         TimerValue *v;
+        Unit *trigger;
 
         assert(t);
         assert(t->state == TIMER_DEAD || t->state == TIMER_FAILED);
 
-        if (UNIT_TRIGGER(u)->load_state != UNIT_LOADED)
+        trigger = UNIT_TRIGGER(u);
+        if (!trigger || trigger->load_state != UNIT_LOADED) {
+                log_unit_error(u->id, "Refusing to start, unit to trigger not loaded.");
                 return -ENOENT;
+        }
 
         t->last_trigger = DUAL_TIMESTAMP_NULL;