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authorLennart Poettering <lennart@poettering.net>2013-11-06 02:03:04 +0100
committerLennart Poettering <lennart@poettering.net>2013-11-06 02:31:35 +0100
commitd3e84ddb885e9d5f0ae9930eb905910e3a81f157 (patch)
tree06f15d176ed35af4b825e901e73d8c8629473963
parentcd6f997f71c3aba16aa08226d423d14cbc787f82 (diff)
machined: keep track of the initial leader PID of a machine
This way we can without races always determine the machine for a leader PID. This allows machine managers to query the machine for a forked off container/VM without a race where the child might already have died before we could read the cgroup information from /proc/$PID/cgroup.
-rw-r--r--src/login/logind-core.c4
-rw-r--r--src/machine/machine.c7
-rw-r--r--src/machine/machined.c9
-rw-r--r--src/machine/machined.h1
4 files changed, 16 insertions, 5 deletions
diff --git a/src/login/logind-core.c b/src/login/logind-core.c
index 6506f22f36..9c31bf8a80 100644
--- a/src/login/logind-core.c
+++ b/src/login/logind-core.c
@@ -348,7 +348,7 @@ int manager_get_session_by_pid(Manager *m, pid_t pid, Session **session) {
r = cg_pid_get_unit(pid, &unit);
if (r < 0)
- return r;
+ return 0;
s = hashmap_get(m->session_units, unit);
if (!s)
@@ -371,7 +371,7 @@ int manager_get_user_by_pid(Manager *m, pid_t pid, User **user) {
r = cg_pid_get_slice(pid, &unit);
if (r < 0)
- return r;
+ return 0;
u = hashmap_get(m->user_units, unit);
if (!u)
diff --git a/src/machine/machine.c b/src/machine/machine.c
index a33a111043..cf3ef15456 100644
--- a/src/machine/machine.c
+++ b/src/machine/machine.c
@@ -85,6 +85,9 @@ void machine_free(Machine *m) {
hashmap_remove(m->manager->machines, m->name);
+ if (m->leader > 0)
+ hashmap_remove_value(m->manager->machine_leaders, UINT_TO_PTR(m->leader), m);
+
sd_bus_message_unref(m->create_message);
free(m->name);
@@ -263,6 +266,10 @@ int machine_start(Machine *m, sd_bus_message *properties, sd_bus_error *error) {
if (m->started)
return 0;
+ r = hashmap_put(m->manager->machine_leaders, UINT_TO_PTR(m->leader), m);
+ if (r < 0)
+ return r;
+
/* Create cgroup */
r = machine_start_scope(m, properties, error);
if (r < 0)
diff --git a/src/machine/machined.c b/src/machine/machined.c
index 25de0d5d46..a5f529384b 100644
--- a/src/machine/machined.c
+++ b/src/machine/machined.c
@@ -46,8 +46,9 @@ Manager *manager_new(void) {
m->machines = hashmap_new(string_hash_func, string_compare_func);
m->machine_units = hashmap_new(string_hash_func, string_compare_func);
+ m->machine_leaders = hashmap_new(trivial_hash_func, trivial_compare_func);
- if (!m->machines || !m->machine_units) {
+ if (!m->machines || !m->machine_units || !m->machine_leaders) {
manager_free(m);
return NULL;
}
@@ -71,6 +72,7 @@ void manager_free(Manager *m) {
hashmap_free(m->machines);
hashmap_free(m->machine_units);
+ hashmap_free(m->machine_leaders);
sd_bus_unref(m->bus);
sd_event_unref(m->event);
@@ -108,9 +110,10 @@ int manager_get_machine_by_pid(Manager *m, pid_t pid, Machine **machine) {
r = cg_pid_get_unit(pid, &unit);
if (r < 0)
- return r;
+ mm = hashmap_get(m->machine_leaders, UINT_TO_PTR(pid));
+ else
+ mm = hashmap_get(m->machine_units, unit);
- mm = hashmap_get(m->machine_units, unit);
if (!mm)
return 0;
diff --git a/src/machine/machined.h b/src/machine/machined.h
index dfb63bd7f1..3f07d4dd8e 100644
--- a/src/machine/machined.h
+++ b/src/machine/machined.h
@@ -40,6 +40,7 @@ struct Manager {
Hashmap *machines;
Hashmap *machine_units;
+ Hashmap *machine_leaders;
LIST_HEAD(Machine, machine_gc_queue);
};