trigger: expose trigger owner uid

[lttng-tools.git] / src / common / trigger.c

diff --git a/src/common/trigger.c b/src/common/trigger.c
index ead0fc259a0eb09af3211df7038aeda00fb28f72..5ae84f3d9e8f6ef28cb6323cd8b83c62101291f8 100644 (file)
--- a/src/common/trigger.c
+++ b/src/common/trigger.c
@@ -25,6 +25,11 @@ bool lttng_trigger_validate(struct lttng_trigger *trigger)
                goto end;
        }
 
+       if (!trigger->creds.uid.is_set) {
+               valid = false;
+               goto end;
+       }
+
        valid = lttng_condition_validate(trigger->condition) &&
                        lttng_action_validate(trigger->action);
 end:
@@ -46,13 +51,23 @@ struct lttng_trigger *lttng_trigger_create(
                goto end;
        }
 
+       urcu_ref_init(&trigger->ref);
+
+       lttng_condition_get(condition);
        trigger->condition = condition;
+
+       lttng_action_get(action);
        trigger->action = action;
 
 end:
        return trigger;
 }
 
+/*
+ * Note: the lack of reference counting 'get' on the condition object is normal.
+ * This API was exposed as such in 2.11. The client is not expected to call
+ * lttng_condition_destroy on the returned object.
+ */
 struct lttng_condition *lttng_trigger_get_condition(
                struct lttng_trigger *trigger)
 {
@@ -66,6 +81,12 @@ const struct lttng_condition *lttng_trigger_get_const_condition(
        return trigger->condition;
 }
 
+
+/*
+ * Note: the lack of reference counting 'get' on the action object is normal.
+ * This API was exposed as such in 2.11. The client is not expected to call
+ * lttng_action_destroy on the returned object.
+ */
 struct lttng_action *lttng_trigger_get_action(
                struct lttng_trigger *trigger)
 {
@@ -79,15 +100,29 @@ const struct lttng_action *lttng_trigger_get_const_action(
        return trigger->action;
 }
 
-void lttng_trigger_destroy(struct lttng_trigger *trigger)
+static void trigger_destroy_ref(struct urcu_ref *ref)
 {
-       if (!trigger) {
-               return;
-       }
+       struct lttng_trigger *trigger =
+                       container_of(ref, struct lttng_trigger, ref);
+       struct lttng_action *action = lttng_trigger_get_action(trigger);
+       struct lttng_condition *condition =
+                       lttng_trigger_get_condition(trigger);
+
+       assert(action);
+       assert(condition);
+
+       /* Release ownership. */
+       lttng_action_put(action);
+       lttng_condition_put(condition);
 
        free(trigger);
 }
 
+void lttng_trigger_destroy(struct lttng_trigger *trigger)
+{
+       lttng_trigger_put(trigger);
+}
+
 LTTNG_HIDDEN
 ssize_t lttng_trigger_create_from_payload(
                struct lttng_payload_view *src_view,
@@ -97,6 +132,10 @@ ssize_t lttng_trigger_create_from_payload(
        struct lttng_condition *condition = NULL;
        struct lttng_action *action = NULL;
        const struct lttng_trigger_comm *trigger_comm;
+       struct lttng_credentials creds = {
+               .uid = LTTNG_OPTIONAL_INIT_UNSET,
+               .gid = LTTNG_OPTIONAL_INIT_UNSET,
+       };
 
        if (!src_view || !trigger) {
                ret = -1;
@@ -105,6 +144,16 @@ ssize_t lttng_trigger_create_from_payload(
 
        /* lttng_trigger_comm header */
        trigger_comm = (typeof(trigger_comm)) src_view->buffer.data;
+
+       /* Set the trigger's creds. */
+       if (trigger_comm->uid > (uint64_t) ((uid_t) -1)) {
+               /* UID out of range for this platform. */
+               ret = -1;
+               goto end;
+       }
+
+       LTTNG_OPTIONAL_SET(&creds.uid, trigger_comm->uid);
+
        offset += sizeof(*trigger_comm);
        {
                /* struct lttng_condition */
@@ -149,12 +198,24 @@ ssize_t lttng_trigger_create_from_payload(
                goto error;
        }
 
+       lttng_trigger_set_credentials(*trigger, &creds);
+
+       /*
+        * The trigger object owns references to the action and condition
+        * objects.
+        */
+       lttng_condition_put(condition);
+       condition = NULL;
+
+       lttng_action_put(action);
+       action = NULL;
+
        ret = offset;
-end:
-       return ret;
+
 error:
        lttng_condition_destroy(condition);
        lttng_action_destroy(action);
+end:
        return ret;
 }
 
@@ -170,6 +231,12 @@ int lttng_trigger_serialize(struct lttng_trigger *trigger,
        size_t header_offset, size_before_payload;
        struct lttng_trigger_comm trigger_comm = {};
        struct lttng_trigger_comm *header;
+       const struct lttng_credentials *creds = NULL;
+
+       creds = lttng_trigger_get_credentials(trigger);
+       assert(creds);
+
+       trigger_comm.uid = LTTNG_OPTIONAL_GET(creds->uid);
 
        header_offset = payload->buffer.size;
        ret = lttng_dynamic_buffer_append(&payload->buffer, &trigger_comm,
@@ -196,18 +263,82 @@ end:
        return ret;
 }
 
+LTTNG_HIDDEN
+void lttng_trigger_get(struct lttng_trigger *trigger)
+{
+       urcu_ref_get(&trigger->ref);
+}
+
+LTTNG_HIDDEN
+void lttng_trigger_put(struct lttng_trigger *trigger)
+{
+       if (!trigger) {
+               return;
+       }
+
+       urcu_ref_put(&trigger->ref , trigger_destroy_ref);
+}
+
 LTTNG_HIDDEN
 const struct lttng_credentials *lttng_trigger_get_credentials(
                const struct lttng_trigger *trigger)
 {
-       return LTTNG_OPTIONAL_GET_PTR(trigger->creds);
+       return &trigger->creds;
 }
 
 LTTNG_HIDDEN
-void lttng_trigger_set_credentials(
-               struct lttng_trigger *trigger,
+void lttng_trigger_set_credentials(struct lttng_trigger *trigger,
                const struct lttng_credentials *creds)
 {
        assert(creds);
-       LTTNG_OPTIONAL_SET(&trigger->creds, *creds);
+       trigger->creds = *creds;
+}
+
+enum lttng_trigger_status lttng_trigger_set_owner_uid(
+               struct lttng_trigger *trigger, uid_t uid)
+{
+       enum lttng_trigger_status ret = LTTNG_TRIGGER_STATUS_OK;
+       const struct lttng_credentials creds = {
+               .uid = LTTNG_OPTIONAL_INIT_VALUE(uid),
+               .gid = LTTNG_OPTIONAL_INIT_UNSET,
+       };
+
+       if (!trigger) {
+               ret = LTTNG_TRIGGER_STATUS_INVALID;
+               goto end;
+       }
+
+       /* Client-side validation only to report a clearer error. */
+       if (geteuid() != 0) {
+               ret = LTTNG_TRIGGER_STATUS_PERMISSION_DENIED;
+               goto end;
+       }
+
+       lttng_trigger_set_credentials(trigger, &creds);
+
+end:
+       return ret;
+}
+
+enum lttng_trigger_status lttng_trigger_get_owner_uid(
+               const struct lttng_trigger *trigger, uid_t *uid)
+{
+       enum lttng_trigger_status ret = LTTNG_TRIGGER_STATUS_OK;
+       const struct lttng_credentials *creds = NULL;
+
+       if (!trigger || !uid ) {
+               ret = LTTNG_TRIGGER_STATUS_INVALID;
+               goto end;
+       }
+
+       if (!trigger->creds.uid.is_set ) {
+               ret = LTTNG_TRIGGER_STATUS_UNSET;
+               goto end;
+       }
+
+       creds = lttng_trigger_get_credentials(trigger);
+       *uid = lttng_credentials_get_uid(creds);
+
+end:
+       return ret;
 }