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 182ba5240f..679fe071e7 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 51e36fa8be..0533bb4e21 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 f318dc6f44..91d8db67e8 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;