SoW-2019-0007-2: Dynamic Snapshot: Triggers send partial event payload with notifications
[lttng-tools.git] / src / bin / lttng-sessiond / kernel.c
index 4ee4bea64ff630abae9617624f86ce21cc87950d..fa682b910350860582ad007ad01ff0ecde9f394f 100644 (file)
@@ -5,6 +5,12 @@
  *
  */
 
+#include "bin/lttng-sessiond/tracker.h"
+#include "common/tracker.h"
+#include "common/utils.h"
+#include "lttng/event.h"
+#include "lttng/lttng-error.h"
+#include "lttng/tracker.h"
 #define _LGPL_SOURCE
 #include <fcntl.h>
 #include <stdlib.h>
 #include <sys/types.h>
 
 #include <common/common.h>
+#include <common/hashtable/utils.h>
 #include <common/trace-chunk.h>
 #include <common/kernel-ctl/kernel-ctl.h>
 #include <common/kernel-ctl/kernel-ioctl.h>
 #include <common/sessiond-comm/sessiond-comm.h>
 
+#include <lttng/userspace-probe.h>
+#include <lttng/userspace-probe-internal.h>
+#include <lttng/condition/event-rule.h>
+#include <lttng/condition/event-rule-internal.h>
+#include <lttng/event-rule/event-rule.h>
+#include <lttng/event-rule/event-rule-internal.h>
+#include <lttng/event-rule/uprobe-internal.h>
+
 #include "lttng-sessiond.h"
 #include "lttng-syscall.h"
 #include "consumer.h"
@@ -29,6 +44,7 @@
 #include "utils.h"
 #include "rotate.h"
 #include "modprobe.h"
+#include "notification-thread-commands.h"
 
 /*
  * Key used to reference a channel between the sessiond and the consumer. This
@@ -39,9 +55,10 @@ static uint64_t next_kernel_channel_key;
 static const char *module_proc_lttng = "/proc/lttng";
 
 static int kernel_tracer_fd = -1;
+static int kernel_tracer_trigger_group_fd = -1;
+static int kernel_tracer_trigger_group_notification_fd = -1;
+static struct ltt_kernel_token_event_rule_list kernel_tracer_token_list;
 
-#include <lttng/userspace-probe.h>
-#include <lttng/userspace-probe-internal.h>
 /*
  * Add context on a kernel channel.
  *
@@ -213,6 +230,44 @@ error:
        return -1;
 }
 
+/*
+ * Create a kernel channel, register it to the kernel tracer and add it to the
+ * kernel session.
+ */
+static
+int kernel_create_trigger_group(int *trigger_group_fd)
+{
+       int ret;
+       int local_fd = -1;
+
+       assert(trigger_group_fd);
+
+       /* Kernel tracer channel creation */
+       ret = kernctl_create_trigger_group(kernel_tracer_fd);
+       if (ret < 0) {
+               PERROR("ioctl kernel create trigger group");
+               ret = -1;
+               goto error;
+       }
+
+       /* Store locally */
+       local_fd = ret;
+
+       /* Prevent fd duplication after execlp() */
+       ret = fcntl(local_fd, F_SETFD, FD_CLOEXEC);
+       if (ret < 0) {
+               PERROR("fcntl session fd");
+       }
+
+       DBG("Kernel trigger group created (fd: %d)",
+                       local_fd);
+       ret = 0;
+
+error:
+       *trigger_group_fd = local_fd;
+       return ret;
+}
+
 /*
  * Compute the offset of the instrumentation byte in the binary based on the
  * function probe location using the ELF lookup method.
@@ -224,7 +279,7 @@ error:
 static
 int extract_userspace_probe_offset_function_elf(
                const struct lttng_userspace_probe_location *probe_location,
-               struct ltt_kernel_session *session, uint64_t *offset)
+               uid_t uid, gid_t gid, uint64_t *offset)
 {
        int fd;
        int ret = 0;
@@ -261,8 +316,7 @@ int extract_userspace_probe_offset_function_elf(
                goto end;
        }
 
-       ret = run_as_extract_elf_symbol_offset(fd, symbol, session->uid,
-                       session->gid, offset);
+       ret = run_as_extract_elf_symbol_offset(fd, symbol, uid, gid, offset);
        if (ret < 0) {
                DBG("userspace probe offset calculation failed for "
                                "function %s", symbol);
@@ -286,7 +340,7 @@ end:
 static
 int extract_userspace_probe_offset_tracepoint_sdt(
                const struct lttng_userspace_probe_location *probe_location,
-               struct ltt_kernel_session *session, uint64_t **offsets,
+               uid_t uid, gid_t gid, uint64_t **offsets,
                uint32_t *offsets_count)
 {
        enum lttng_userspace_probe_location_lookup_method_type lookup_method_type;
@@ -332,7 +386,7 @@ int extract_userspace_probe_offset_tracepoint_sdt(
        }
 
        ret = run_as_extract_sdt_probe_offsets(fd, provider_name, probe_name,
-                       session->uid, session->gid, offsets, offsets_count);
+                       uid, gid, offsets, offsets_count);
        if (ret < 0) {
                DBG("userspace probe offset calculation failed for sdt "
                                "probe %s:%s", provider_name, probe_name);
@@ -353,29 +407,16 @@ end:
        return ret;
 }
 
-/*
- * Extract the offsets of the instrumentation point for the different lookup
- * methods.
- */
 static
-int userspace_probe_add_callsites(struct lttng_event *ev,
-                       struct ltt_kernel_session *session, int fd)
+int userspace_probe_add_callsite(
+               const struct lttng_userspace_probe_location *location,
+               uid_t uid, gid_t gid, int fd)
 {
        const struct lttng_userspace_probe_location_lookup_method *lookup_method = NULL;
        enum lttng_userspace_probe_location_lookup_method_type type;
-       const struct lttng_userspace_probe_location *location = NULL;
        int ret;
 
-       assert(ev);
-       assert(ev->type == LTTNG_EVENT_USERSPACE_PROBE);
-
-       location = lttng_event_get_userspace_probe_location(ev);
-       if (!location) {
-               ret = -1;
-               goto end;
-       }
-       lookup_method =
-                       lttng_userspace_probe_location_get_lookup_method(location);
+       lookup_method = lttng_userspace_probe_location_get_lookup_method(location);
        if (!lookup_method) {
                ret = -1;
                goto end;
@@ -388,7 +429,8 @@ int userspace_probe_add_callsites(struct lttng_event *ev,
                struct lttng_kernel_event_callsite callsite;
                uint64_t offset;
 
-               ret = extract_userspace_probe_offset_function_elf(location, session, &offset);
+               ret = extract_userspace_probe_offset_function_elf(location,
+                               uid, gid, &offset);
                if (ret) {
                        ret = LTTNG_ERR_PROBE_LOCATION_INVAL;
                        goto end;
@@ -397,8 +439,7 @@ int userspace_probe_add_callsites(struct lttng_event *ev,
                callsite.u.uprobe.offset = offset;
                ret = kernctl_add_callsite(fd, &callsite);
                if (ret) {
-                       WARN("Adding callsite to userspace probe "
-                                       "event %s failed.", ev->name);
+                       WARN("Adding callsite to ELF userspace probe failed.");
                        ret = LTTNG_ERR_KERN_ENABLE_FAIL;
                        goto end;
                }
@@ -415,8 +456,8 @@ int userspace_probe_add_callsites(struct lttng_event *ev,
                 * This call allocates the offsets buffer. This buffer must be freed
                 * by the caller
                 */
-               ret = extract_userspace_probe_offset_tracepoint_sdt(location, session,
-                               &offsets, &offsets_count);
+               ret = extract_userspace_probe_offset_tracepoint_sdt(location,
+                               uid, gid, &offsets, &offsets_count);
                if (ret) {
                        ret = LTTNG_ERR_PROBE_LOCATION_INVAL;
                        goto end;
@@ -425,8 +466,8 @@ int userspace_probe_add_callsites(struct lttng_event *ev,
                        callsite.u.uprobe.offset = offsets[i];
                        ret = kernctl_add_callsite(fd, &callsite);
                        if (ret) {
-                               WARN("Adding callsite to userspace probe "
-                                               "event %s failed.", ev->name);
+                               WARN("Adding callsite to SDT userspace probe "
+                                       "failed.");
                                ret = LTTNG_ERR_KERN_ENABLE_FAIL;
                                free(offsets);
                                goto end;
@@ -443,6 +484,71 @@ end:
        return ret;
 }
 
+/*
+ * Extract the offsets of the instrumentation point for the different lookup
+ * methods.
+ */
+static
+int userspace_probe_event_add_callsites(struct lttng_event *ev,
+                       struct ltt_kernel_session *session, int fd)
+{
+       const struct lttng_userspace_probe_location *location = NULL;
+       int ret;
+
+       assert(ev);
+       assert(ev->type == LTTNG_EVENT_USERSPACE_PROBE);
+
+       location = lttng_event_get_userspace_probe_location(ev);
+       if (!location) {
+               ret = -1;
+               goto end;
+       }
+
+       ret = userspace_probe_add_callsite(location, session->uid, session->gid,
+               fd);
+       if (ret) {
+               WARN("Adding callsite to userspace probe event \"%s\" "
+                       "failed.", ev->name);
+       }
+
+end:
+       return ret;
+}
+
+/*
+ * Extract the offsets of the instrumentation point for the different lookup
+ * methods.
+ */
+static int userspace_probe_event_rule_add_callsites(
+               const struct lttng_event_rule *rule,
+               const struct lttng_credentials *creds,
+               int fd)
+{
+       const struct lttng_userspace_probe_location *location = NULL;
+       enum lttng_event_rule_status status;
+       int ret;
+
+       assert(rule);
+       assert(creds);
+       assert(lttng_event_rule_get_type(rule) == LTTNG_EVENT_RULE_TYPE_UPROBE);
+
+       status = lttng_event_rule_uprobe_get_location(rule, &location);
+       if (status != LTTNG_EVENT_RULE_STATUS_OK || !location) {
+               ret = -1;
+               goto end;
+       }
+
+       ret = userspace_probe_add_callsite(location, creds->uid, creds->gid,
+               fd);
+       if (ret) {
+               WARN("Adding callsite to userspace probe object %d"
+                       "failed.", fd);
+       }
+
+end:
+       return ret;
+}
+
 /*
  * Create a kernel event, enable it to the kernel tracer and add it to the
  * channel event list of the kernel session.
@@ -451,7 +557,7 @@ end:
 int kernel_create_event(struct lttng_event *ev,
                struct ltt_kernel_channel *channel,
                char *filter_expression,
-               struct lttng_filter_bytecode *filter)
+               struct lttng_bytecode *filter)
 {
        int err, fd;
        enum lttng_error_code ret;
@@ -512,7 +618,8 @@ int kernel_create_event(struct lttng_event *ev,
        }
 
        if (ev->type == LTTNG_EVENT_USERSPACE_PROBE) {
-               ret = userspace_probe_add_callsites(ev, channel->session, event->fd);
+               ret = userspace_probe_event_add_callsites(ev, channel->session,
+                       event->fd);
                if (ret) {
                        goto add_callsite_error;
                }
@@ -669,281 +776,402 @@ error:
        return ret;
 }
 
-static struct lttng_tracker_list *get_id_tracker_list(
+/*
+ * Disable a kernel trigger.
+ */
+static
+int kernel_disable_token_event_rule(struct ltt_kernel_token_event_rule *event)
+{
+       int ret;
+
+       assert(event);
+
+       ret = kernctl_disable(event->fd);
+       if (ret < 0) {
+               switch (-ret) {
+               case EEXIST:
+                       ret = LTTNG_ERR_KERN_EVENT_EXIST;
+                       break;
+               default:
+                       PERROR("disable kernel event");
+                       break;
+               }
+               goto error;
+       }
+
+       event->enabled = 0;
+       DBG("Kernel trigger token %" PRIu64" disabled (fd: %d)", event->token, event->fd);
+
+       return 0;
+
+error:
+       return ret;
+}
+
+static
+struct process_attr_tracker *_kernel_get_process_attr_tracker(
                struct ltt_kernel_session *session,
-               enum lttng_tracker_type tracker_type)
+               enum lttng_process_attr process_attr)
 {
-       switch (tracker_type) {
-       case LTTNG_TRACKER_PID:
-               return session->tracker_list_pid;
-       case LTTNG_TRACKER_VPID:
-               return session->tracker_list_vpid;
-       case LTTNG_TRACKER_UID:
-               return session->tracker_list_uid;
-       case LTTNG_TRACKER_VUID:
-               return session->tracker_list_vuid;
-       case LTTNG_TRACKER_GID:
-               return session->tracker_list_gid;
-       case LTTNG_TRACKER_VGID:
-               return session->tracker_list_vgid;
+       switch (process_attr) {
+       case LTTNG_PROCESS_ATTR_PROCESS_ID:
+               return session->tracker_pid;
+       case LTTNG_PROCESS_ATTR_VIRTUAL_PROCESS_ID:
+               return session->tracker_vpid;
+       case LTTNG_PROCESS_ATTR_USER_ID:
+               return session->tracker_uid;
+       case LTTNG_PROCESS_ATTR_VIRTUAL_USER_ID:
+               return session->tracker_vuid;
+       case LTTNG_PROCESS_ATTR_GROUP_ID:
+               return session->tracker_gid;
+       case LTTNG_PROCESS_ATTR_VIRTUAL_GROUP_ID:
+               return session->tracker_vgid;
        default:
                return NULL;
        }
 }
 
-int kernel_track_id(enum lttng_tracker_type tracker_type,
+const struct process_attr_tracker *kernel_get_process_attr_tracker(
                struct ltt_kernel_session *session,
-               const struct lttng_tracker_id *id)
+               enum lttng_process_attr process_attr)
 {
-       int ret, value;
-       struct lttng_tracker_list *tracker_list;
-       struct lttng_tracker_ids *saved_ids;
+       return (const struct process_attr_tracker *)
+                       _kernel_get_process_attr_tracker(session, process_attr);
+}
 
-       ret = lttng_tracker_id_lookup_string(tracker_type, id, &value);
-       if (ret != LTTNG_OK) {
-               return ret;
-       }
+enum lttng_error_code kernel_process_attr_tracker_set_tracking_policy(
+               struct ltt_kernel_session *session,
+               enum lttng_process_attr process_attr,
+               enum lttng_tracking_policy policy)
+{
+       int ret;
+       enum lttng_error_code ret_code = LTTNG_OK;
+       struct process_attr_tracker *tracker =
+                       _kernel_get_process_attr_tracker(session, process_attr);
+       enum lttng_tracking_policy previous_policy;
 
-       tracker_list = get_id_tracker_list(session, tracker_type);
-       if (!tracker_list) {
-               return LTTNG_ERR_INVALID;
+       if (!tracker) {
+               ret_code = LTTNG_ERR_INVALID;
+               goto end;
        }
 
-       /* Save list for restore on error. */
-       ret = lttng_tracker_id_get_list(tracker_list, &saved_ids);
-       if (ret != LTTNG_OK) {
-               return LTTNG_ERR_INVALID;
+       previous_policy = process_attr_tracker_get_tracking_policy(tracker);
+       ret = process_attr_tracker_set_tracking_policy(tracker, policy);
+       if (ret) {
+               ret_code = LTTNG_ERR_UNK;
+               goto end;
        }
 
-       /* Add to list. */
-       ret = lttng_tracker_list_add(tracker_list, id);
-       if (ret != LTTNG_OK) {
+       if (previous_policy == policy) {
                goto end;
        }
 
-       switch (tracker_type) {
-       case LTTNG_TRACKER_PID:
-               DBG("Kernel track PID %d for session id %" PRIu64 ".", value,
-                               session->id);
-               ret = kernctl_track_pid(session->fd, value);
-               if (!ret) {
-                       ret = LTTNG_OK;
-                       goto end;
-               }
-               break;
-       case LTTNG_TRACKER_VPID:
-               DBG("Kernel track VPID %d for session id %" PRIu64 ".", value,
-                               session->id);
-               ret = kernctl_track_id(session->fd, LTTNG_TRACKER_VPID, value);
-               if (!ret) {
-                       ret = LTTNG_OK;
-                       goto end;
-               }
-               break;
-       case LTTNG_TRACKER_UID:
-               DBG("Kernel track UID %d for session id %" PRIu64 ".", value,
-                               session->id);
-               ret = kernctl_track_id(session->fd, LTTNG_TRACKER_UID, value);
-               if (!ret) {
-                       ret = LTTNG_OK;
-                       goto end;
-               }
-               break;
-       case LTTNG_TRACKER_GID:
-               DBG("Kernel track GID %d for session id %" PRIu64 ".", value,
-                               session->id);
-               ret = kernctl_track_id(session->fd, LTTNG_TRACKER_GID, value);
-               if (!ret) {
-                       ret = LTTNG_OK;
-                       goto end;
-               }
-               break;
-       case LTTNG_TRACKER_VUID:
-               DBG("Kernel track VUID %d for session id %" PRIu64 ".", value,
-                               session->id);
-               ret = kernctl_track_id(session->fd, LTTNG_TRACKER_VUID, value);
-               if (!ret) {
-                       ret = LTTNG_OK;
-                       goto end;
+       switch (policy) {
+       case LTTNG_TRACKING_POLICY_INCLUDE_ALL:
+               if (process_attr == LTTNG_PROCESS_ATTR_PROCESS_ID) {
+                       /*
+                        * Maintain a special case for the process ID process
+                        * attribute tracker as it was the only supported
+                        * attribute prior to 2.12.
+                        */
+                       ret = kernctl_track_pid(session->fd, -1);
+               } else {
+                       ret = kernctl_track_id(session->fd, process_attr, -1);
                }
                break;
-       case LTTNG_TRACKER_VGID:
-               DBG("Kernel track VGID %d for session id %" PRIu64 ".", value,
-                               session->id);
-               ret = kernctl_track_id(session->fd, LTTNG_TRACKER_VGID, value);
-               if (!ret) {
-                       ret = LTTNG_OK;
-                       goto end;
+       case LTTNG_TRACKING_POLICY_EXCLUDE_ALL:
+       case LTTNG_TRACKING_POLICY_INCLUDE_SET:
+               /* fall-through. */
+               if (process_attr == LTTNG_PROCESS_ATTR_PROCESS_ID) {
+                       /*
+                        * Maintain a special case for the process ID process
+                        * attribute tracker as it was the only supported
+                        * attribute prior to 2.12.
+                        */
+                       ret = kernctl_untrack_pid(session->fd, -1);
+               } else {
+                       ret = kernctl_untrack_id(session->fd, process_attr, -1);
                }
                break;
        default:
-               ret = -EINVAL;
-               break;
+               abort();
        }
-
-       /* Error handling. */
+       /* kern-ctl error handling */
        switch (-ret) {
+       case 0:
+               ret_code = LTTNG_OK;
+               break;
        case EINVAL:
-               ret = LTTNG_ERR_INVALID;
+               ret_code = LTTNG_ERR_INVALID;
                break;
        case ENOMEM:
-               ret = LTTNG_ERR_NOMEM;
+               ret_code = LTTNG_ERR_NOMEM;
                break;
        case EEXIST:
-               ret = LTTNG_ERR_ID_TRACKED;
+               ret_code = LTTNG_ERR_PROCESS_ATTR_EXISTS;
                break;
        default:
-               ret = LTTNG_ERR_UNK;
+               ret_code = LTTNG_ERR_UNK;
                break;
        }
-
-       if (lttng_tracker_id_set_list(tracker_list, saved_ids) != LTTNG_OK) {
-               ERR("Error on tracker add error handling.\n");
-       }
 end:
-       lttng_tracker_ids_destroy(saved_ids);
-       return ret;
+       return ret_code;
 }
 
-int kernel_untrack_id(enum lttng_tracker_type tracker_type,
+enum lttng_error_code kernel_process_attr_tracker_inclusion_set_add_value(
                struct ltt_kernel_session *session,
-               const struct lttng_tracker_id *id)
+               enum lttng_process_attr process_attr,
+               const struct process_attr_value *value)
 {
-       int ret, value;
-       struct lttng_tracker_list *tracker_list;
-       struct lttng_tracker_ids *saved_ids;
+       int ret, integral_value;
+       enum lttng_error_code ret_code;
+       struct process_attr_tracker *tracker;
+       enum process_attr_tracker_status status;
 
-       ret = lttng_tracker_id_lookup_string(tracker_type, id, &value);
-       if (ret != LTTNG_OK) {
-               return ret;
-       }
-
-       tracker_list = get_id_tracker_list(session, tracker_type);
-       if (!tracker_list) {
-               return LTTNG_ERR_INVALID;
-       }
-       /* Save list for restore on error. */
-       ret = lttng_tracker_id_get_list(tracker_list, &saved_ids);
-       if (ret != LTTNG_OK) {
-               return LTTNG_ERR_INVALID;
-       }
-       /* Remove from list. */
-       ret = lttng_tracker_list_remove(tracker_list, id);
-       if (ret != LTTNG_OK) {
-               goto end;
-       }
-
-       switch (tracker_type) {
-       case LTTNG_TRACKER_PID:
-               DBG("Kernel untrack PID %d for session id %" PRIu64 ".", value,
-                               session->id);
-               ret = kernctl_untrack_pid(session->fd, value);
-               if (!ret) {
-                       ret = LTTNG_OK;
-                       goto end;
-               }
-               break;
-       case LTTNG_TRACKER_VPID:
-               DBG("Kernel untrack VPID %d for session id %" PRIu64 ".", value,
-                               session->id);
-               ret = kernctl_untrack_id(
-                               session->fd, LTTNG_TRACKER_VPID, value);
-               if (!ret) {
-                       ret = LTTNG_OK;
-                       goto end;
-               }
-               break;
-       case LTTNG_TRACKER_UID:
-               DBG("Kernel untrack UID %d for session id %" PRIu64 ".", value,
-                               session->id);
-               ret = kernctl_untrack_id(session->fd, LTTNG_TRACKER_UID, value);
-               if (!ret) {
-                       ret = LTTNG_OK;
-                       goto end;
-               }
-               break;
-       case LTTNG_TRACKER_GID:
-               DBG("Kernel untrack GID %d for session id %" PRIu64 ".", value,
-                               session->id);
-               ret = kernctl_untrack_id(session->fd, LTTNG_TRACKER_GID, value);
-               if (!ret) {
-                       ret = LTTNG_OK;
-                       goto end;
-               }
+       /*
+        * Convert process attribute tracker value to the integral
+        * representation required by the kern-ctl API.
+        */
+       switch (process_attr) {
+       case LTTNG_PROCESS_ATTR_PROCESS_ID:
+       case LTTNG_PROCESS_ATTR_VIRTUAL_PROCESS_ID:
+               integral_value = (int) value->value.pid;
                break;
-       case LTTNG_TRACKER_VUID:
-               DBG("Kernel untrack VUID %d for session id %" PRIu64 ".", value,
-                               session->id);
-               ret = kernctl_untrack_id(
-                               session->fd, LTTNG_TRACKER_VUID, value);
-               if (!ret) {
-                       ret = LTTNG_OK;
-                       goto end;
+       case LTTNG_PROCESS_ATTR_USER_ID:
+       case LTTNG_PROCESS_ATTR_VIRTUAL_USER_ID:
+               if (value->type == LTTNG_PROCESS_ATTR_VALUE_TYPE_USER_NAME) {
+                       uid_t uid;
+
+                       ret_code = utils_user_id_from_name(
+                                       value->value.user_name, &uid);
+                       if (ret_code != LTTNG_OK) {
+                               goto end;
+                       }
+                       integral_value = (int) uid;
+               } else {
+                       integral_value = (int) value->value.uid;
                }
                break;
-       case LTTNG_TRACKER_VGID:
-               DBG("Kernel untrack VGID %d for session id %" PRIu64 ".", value,
-                               session->id);
-               ret = kernctl_untrack_id(
-                               session->fd, LTTNG_TRACKER_VGID, value);
-               if (!ret) {
-                       ret = LTTNG_OK;
-                       goto end;
+       case LTTNG_PROCESS_ATTR_GROUP_ID:
+       case LTTNG_PROCESS_ATTR_VIRTUAL_GROUP_ID:
+               if (value->type == LTTNG_PROCESS_ATTR_VALUE_TYPE_GROUP_NAME) {
+                       gid_t gid;
+
+                       ret_code = utils_group_id_from_name(
+                                       value->value.group_name, &gid);
+                       if (ret_code != LTTNG_OK) {
+                               goto end;
+                       }
+                       integral_value = (int) gid;
+               } else {
+                       integral_value = (int) value->value.gid;
                }
                break;
        default:
-               ret = -EINVAL;
-               break;
+               ret_code = LTTNG_ERR_INVALID;
+               goto end;
+       }
+
+       tracker = _kernel_get_process_attr_tracker(session, process_attr);
+       if (!tracker) {
+               ret_code = LTTNG_ERR_INVALID;
+               goto end;
        }
 
-       /* Error handling. */
+       status = process_attr_tracker_inclusion_set_add_value(tracker, value);
+       if (status != PROCESS_ATTR_TRACKER_STATUS_OK) {
+               switch (status) {
+               case PROCESS_ATTR_TRACKER_STATUS_EXISTS:
+                       ret_code = LTTNG_ERR_PROCESS_ATTR_EXISTS;
+                       break;
+               case PROCESS_ATTR_TRACKER_STATUS_INVALID_TRACKING_POLICY:
+                       ret_code = LTTNG_ERR_PROCESS_ATTR_TRACKER_INVALID_TRACKING_POLICY;
+                       break;
+               case PROCESS_ATTR_TRACKER_STATUS_ERROR:
+               default:
+                       ret_code = LTTNG_ERR_UNK;
+                       break;
+               }
+               goto end;
+       }
+
+       DBG("Kernel track %s %d for session id %" PRIu64,
+                       lttng_process_attr_to_string(process_attr),
+                       integral_value, session->id);
+       if (process_attr == LTTNG_PROCESS_ATTR_PROCESS_ID) {
+               /*
+                * Maintain a special case for the process ID process attribute
+                * tracker as it was the only supported attribute prior to 2.12.
+                */
+               ret = kernctl_track_pid(session->fd, integral_value);
+       } else {
+               ret = kernctl_track_id(
+                               session->fd, process_attr, integral_value);
+       }
+       if (ret == 0) {
+               ret_code = LTTNG_OK;
+               goto end;
+       }
+
+       kernel_wait_quiescent();
+
+       /* kern-ctl error handling */
        switch (-ret) {
+       case 0:
+               ret_code = LTTNG_OK;
+               break;
        case EINVAL:
-               ret = LTTNG_ERR_INVALID;
+               ret_code = LTTNG_ERR_INVALID;
                break;
        case ENOMEM:
-               ret = LTTNG_ERR_NOMEM;
+               ret_code = LTTNG_ERR_NOMEM;
                break;
        case EEXIST:
-               ret = LTTNG_ERR_ID_TRACKED;
+               ret_code = LTTNG_ERR_PROCESS_ATTR_EXISTS;
                break;
        default:
-               ret = LTTNG_ERR_UNK;
+               ret_code = LTTNG_ERR_UNK;
                break;
        }
 
-       if (lttng_tracker_id_set_list(tracker_list, saved_ids) != LTTNG_OK) {
-               ERR("Error on tracker remove error handling.\n");
+       /* Attempt to remove the value from the tracker. */
+       status = process_attr_tracker_inclusion_set_remove_value(
+                       tracker, value);
+       if (status != PROCESS_ATTR_TRACKER_STATUS_OK) {
+               ERR("Failed to roll-back the tracking of kernel %s process attribute %d while handling a kern-ctl error",
+                               lttng_process_attr_to_string(process_attr),
+                               integral_value);
        }
 end:
-       lttng_tracker_ids_destroy(saved_ids);
-       return ret;
+       return ret_code;
 }
 
-/*
- * Called with session lock held.
- */
-int kernel_list_tracker_ids(enum lttng_tracker_type tracker_type,
+enum lttng_error_code kernel_process_attr_tracker_inclusion_set_remove_value(
                struct ltt_kernel_session *session,
-               struct lttng_tracker_ids **_ids)
+               enum lttng_process_attr process_attr,
+               const struct process_attr_value *value)
 {
-       int ret = 0;
-       struct lttng_tracker_list *tracker_list;
+       int ret, integral_value;
+       enum lttng_error_code ret_code;
+       struct process_attr_tracker *tracker;
+       enum process_attr_tracker_status status;
 
-       tracker_list = get_id_tracker_list(session, tracker_type);
-       if (!tracker_list) {
-               ret = -LTTNG_ERR_INVALID;
+       /*
+        * Convert process attribute tracker value to the integral
+        * representation required by the kern-ctl API.
+        */
+       switch (process_attr) {
+       case LTTNG_PROCESS_ATTR_PROCESS_ID:
+       case LTTNG_PROCESS_ATTR_VIRTUAL_PROCESS_ID:
+               integral_value = (int) value->value.pid;
+               break;
+       case LTTNG_PROCESS_ATTR_USER_ID:
+       case LTTNG_PROCESS_ATTR_VIRTUAL_USER_ID:
+               if (value->type == LTTNG_PROCESS_ATTR_VALUE_TYPE_USER_NAME) {
+                       uid_t uid;
+
+                       ret_code = utils_user_id_from_name(
+                                       value->value.user_name, &uid);
+                       if (ret_code != LTTNG_OK) {
+                               goto end;
+                       }
+                       integral_value = (int) uid;
+               } else {
+                       integral_value = (int) value->value.uid;
+               }
+               break;
+       case LTTNG_PROCESS_ATTR_GROUP_ID:
+       case LTTNG_PROCESS_ATTR_VIRTUAL_GROUP_ID:
+               if (value->type == LTTNG_PROCESS_ATTR_VALUE_TYPE_GROUP_NAME) {
+                       gid_t gid;
+
+                       ret_code = utils_group_id_from_name(
+                                       value->value.group_name, &gid);
+                       if (ret_code != LTTNG_OK) {
+                               goto end;
+                       }
+                       integral_value = (int) gid;
+               } else {
+                       integral_value = (int) value->value.gid;
+               }
+               break;
+       default:
+               ret_code = LTTNG_ERR_INVALID;
                goto end;
        }
 
-       ret = lttng_tracker_id_get_list(tracker_list, _ids);
-       if (ret != LTTNG_OK) {
-               ret = -LTTNG_ERR_INVALID;
+       tracker = _kernel_get_process_attr_tracker(session, process_attr);
+       if (!tracker) {
+               ret_code = LTTNG_ERR_INVALID;
                goto end;
        }
 
+       status = process_attr_tracker_inclusion_set_remove_value(
+                       tracker, value);
+       if (status != PROCESS_ATTR_TRACKER_STATUS_OK) {
+               switch (status) {
+               case PROCESS_ATTR_TRACKER_STATUS_MISSING:
+                       ret_code = LTTNG_ERR_PROCESS_ATTR_MISSING;
+                       break;
+               case PROCESS_ATTR_TRACKER_STATUS_INVALID_TRACKING_POLICY:
+                       ret_code = LTTNG_ERR_PROCESS_ATTR_TRACKER_INVALID_TRACKING_POLICY;
+                       break;
+               case PROCESS_ATTR_TRACKER_STATUS_ERROR:
+               default:
+                       ret_code = LTTNG_ERR_UNK;
+                       break;
+               }
+               goto end;
+       }
+
+       DBG("Kernel track %s %d for session id %" PRIu64,
+                       lttng_process_attr_to_string(process_attr),
+                       integral_value, session->id);
+       if (process_attr == LTTNG_PROCESS_ATTR_PROCESS_ID) {
+               /*
+                * Maintain a special case for the process ID process attribute
+                * tracker as it was the only supported attribute prior to 2.12.
+                */
+               ret = kernctl_untrack_pid(session->fd, integral_value);
+       } else {
+               ret = kernctl_untrack_id(
+                               session->fd, process_attr, integral_value);
+       }
+       if (ret == 0) {
+               ret_code = LTTNG_OK;
+               goto end;
+       }
+       kernel_wait_quiescent();
+
+       /* kern-ctl error handling */
+       switch (-ret) {
+       case 0:
+               ret_code = LTTNG_OK;
+               break;
+       case EINVAL:
+               ret_code = LTTNG_ERR_INVALID;
+               break;
+       case ENOMEM:
+               ret_code = LTTNG_ERR_NOMEM;
+               break;
+       case ENOENT:
+               ret_code = LTTNG_ERR_PROCESS_ATTR_MISSING;
+               break;
+       default:
+               ret_code = LTTNG_ERR_UNK;
+               break;
+       }
+
+       /* Attempt to add the value to the tracker. */
+       status = process_attr_tracker_inclusion_set_add_value(
+                       tracker, value);
+       if (status != PROCESS_ATTR_TRACKER_STATUS_OK) {
+               ERR("Failed to roll-back the tracking of kernel %s process attribute %d while handling a kern-ctl error",
+                               lttng_process_attr_to_string(process_attr),
+                               integral_value);
+       }
 end:
-       return ret;
+       return ret_code;
 }
 
 /*
@@ -1647,7 +1875,7 @@ enum lttng_error_code kernel_rotate_session(struct ltt_session *session)
                                        ksess->uid, ksess->gid, ksess->consumer,
                                        /* is_metadata_channel */ false);
                        if (ret < 0) {
-                               status = LTTNG_ERR_KERN_CONSUMER_FAIL;
+                               status = LTTNG_ERR_ROTATION_FAIL_CONSUMER;
                                goto error;
                        }
                }
@@ -1659,7 +1887,7 @@ enum lttng_error_code kernel_rotate_session(struct ltt_session *session)
                                ksess->uid, ksess->gid, ksess->consumer,
                                /* is_metadata_channel */ true);
                if (ret < 0) {
-                       status = LTTNG_ERR_KERN_CONSUMER_FAIL;
+                       status = LTTNG_ERR_ROTATION_FAIL_CONSUMER;
                        goto error;
                }
        }
@@ -1732,20 +1960,37 @@ int init_kernel_tracer(void)
        if (ret < 0) {
                goto error_modules;
        }
-
        if (ret < 1) {
                WARN("Kernel tracer does not support buffer monitoring. "
                        "The monitoring timer of channels in the kernel domain "
                        "will be set to 0 (disabled).");
        }
 
+       ret = kernel_create_trigger_group(&kernel_tracer_trigger_group_fd);
+       if (ret < 0) {
+               /* TODO: error handling if it is not supported etc. */
+               WARN("Failed trigger group creation");
+               kernel_tracer_trigger_group_fd = -1;
+               /* This is not fatal */
+       } else {
+               ret = kernel_create_trigger_group_notification_fd(&kernel_tracer_trigger_group_notification_fd);
+               if (ret < 0) {
+                       goto error_modules;
+               }
+       }
+
+       CDS_INIT_LIST_HEAD(&kernel_tracer_token_list.head);
+
        DBG("Kernel tracer fd %d", kernel_tracer_fd);
+       DBG("Kernel tracer trigger group fd %d", kernel_tracer_trigger_group_fd);
+       DBG("Kernel tracer trigger group notificationi fd %d", kernel_tracer_trigger_group_notification_fd);
 
        ret = syscall_init_table(kernel_tracer_fd);
        if (ret < 0) {
                ERR("Unable to populate syscall table. Syscall tracing won't "
                        "work for this session daemon.");
        }
+
        return 0;
 
 error_version:
@@ -1781,6 +2026,31 @@ void cleanup_kernel_tracer(void)
 {
        int ret;
 
+       struct ltt_kernel_token_event_rule *rule, *rtmp;
+        cds_list_for_each_entry_safe(rule, rtmp, &kernel_tracer_token_list.head, list) {
+               kernel_disable_token_event_rule(rule);
+               trace_kernel_destroy_token_event_rule(rule);
+       }
+
+       DBG2("Closing kernel trigger group notification fd");
+       if (kernel_tracer_trigger_group_notification_fd >= 0) {
+               ret = close(kernel_tracer_trigger_group_notification_fd);
+               if (ret) {
+                       PERROR("close");
+               }
+               kernel_tracer_trigger_group_notification_fd = -1;
+       }
+
+       /* TODO: do we iterate over the list to remove all token? */
+       DBG2("Closing kernel trigger group fd");
+       if (kernel_tracer_trigger_group_fd >= 0) {
+               ret = close(kernel_tracer_trigger_group_fd);
+               if (ret) {
+                       PERROR("close");
+               }
+               kernel_tracer_trigger_group_fd = -1;
+       }
+
        DBG2("Closing kernel fd");
        if (kernel_tracer_fd >= 0) {
                ret = close(kernel_tracer_fd);
@@ -1789,6 +2059,7 @@ void cleanup_kernel_tracer(void)
                }
                kernel_tracer_fd = -1;
        }
+
        DBG("Unloading kernel modules");
        modprobe_remove_lttng_all();
        free(syscall_table);
@@ -1879,3 +2150,298 @@ end:
        rcu_read_unlock();
        return status;
 }
+
+enum lttng_error_code kernel_create_trigger_group_notification_fd(
+               int *trigger_group_notification_fd)
+{
+       enum lttng_error_code ret = LTTNG_OK;
+       int local_fd = -1;
+
+       assert(trigger_group_notification_fd);
+
+       ret = kernctl_create_trigger_group_notification_fd(kernel_tracer_trigger_group_fd);
+       if (ret < 0) {
+               PERROR("ioctl kernel create trigger group");
+               ret = -1;
+               goto error;
+       }
+
+       /* Store locally */
+       local_fd = ret;
+
+       /* Prevent fd duplication after execlp() */
+       ret = fcntl(local_fd, F_SETFD, FD_CLOEXEC);
+       if (ret < 0) {
+               PERROR("fcntl session fd");
+       }
+
+       DBG("Kernel trigger group notification created (fd: %d)",
+                       local_fd);
+       ret = 0;
+
+error:
+       *trigger_group_notification_fd = local_fd;
+       return ret;
+}
+
+enum lttng_error_code kernel_destroy_trigger_group_notification_fd(
+               int trigger_group_notification_fd)
+{
+       enum lttng_error_code ret = LTTNG_OK;
+       DBG("Closing trigger group notification fd %d", trigger_group_notification_fd);
+       if (trigger_group_notification_fd >= 0) {
+               ret = close(trigger_group_notification_fd);
+               if (ret) {
+                       PERROR("close");
+               }
+       }
+       return ret;
+}
+
+static int kernel_create_token_event_rule(struct lttng_trigger *trigger,
+               const struct lttng_credentials *creds, uint64_t token)
+{
+       int err, fd;
+       enum lttng_error_code ret;
+       struct ltt_kernel_token_event_rule *event;
+       struct lttng_kernel_trigger kernel_trigger;
+       unsigned int capture_bytecode_count = 0;
+       struct lttng_condition *condition = NULL;
+       struct lttng_event_rule *event_rule = NULL;
+
+       assert(trigger);
+
+       condition = lttng_trigger_get_condition(trigger);
+       assert(condition);
+       assert(lttng_condition_get_type(condition) == LTTNG_CONDITION_TYPE_EVENT_RULE_HIT);
+
+       lttng_condition_event_rule_get_rule_no_const(condition, &event_rule);
+       assert(event_rule);
+       assert(lttng_event_rule_get_type(event_rule) != LTTNG_EVENT_RULE_TYPE_UNKNOWN);
+
+       /* TODO: Should we check that the event-rule is kernel oriented here? */
+
+       ret = trace_kernel_create_token_event_rule(event_rule, token, &event);
+       if (ret != LTTNG_OK) {
+               goto error;
+       }
+       
+       trace_kernel_init_trigger_from_event_rule(event->event_rule, &kernel_trigger);
+       kernel_trigger.id = event->token;
+
+       fd = kernctl_create_trigger(kernel_tracer_trigger_group_fd, &kernel_trigger);
+       if (fd < 0) {
+               switch (-fd) {
+               case EEXIST:
+                       ret = LTTNG_ERR_KERN_EVENT_EXIST;
+                       break;
+               case ENOSYS:
+                       WARN("Trigger type not implemented");
+                       ret = LTTNG_ERR_KERN_EVENT_ENOSYS;
+                       break;
+               case ENOENT:
+                       WARN("Event %s not found!", kernel_trigger.name);
+                       ret = LTTNG_ERR_KERN_ENABLE_FAIL;
+                       break;
+               default:
+                       ret = LTTNG_ERR_KERN_ENABLE_FAIL;
+                       PERROR("create trigger ioctl");
+               }
+               goto free_event;
+       }
+
+       event->fd = fd;
+       /* Prevent fd duplication after execlp() */
+       err = fcntl(event->fd, F_SETFD, FD_CLOEXEC);
+       if (err < 0) {
+               PERROR("fcntl session fd");
+       }
+
+       if (event->filter) {
+               err = kernctl_filter(event->fd, event->filter);
+               if (err < 0) {
+                       switch (-err) {
+                       case ENOMEM:
+                               ret = LTTNG_ERR_FILTER_NOMEM;
+                               break;
+                       default:
+                               ret = LTTNG_ERR_FILTER_INVAL;
+                               break;
+                       }
+                       goto filter_error;
+               }
+       }
+
+       if (lttng_event_rule_get_type(event->event_rule) ==
+                       LTTNG_EVENT_RULE_TYPE_UPROBE) {
+               ret = userspace_probe_event_rule_add_callsites(
+                               event->event_rule, creds, event->fd);
+               if (ret) {
+                       goto add_callsite_error;
+               }
+       }
+
+       /* Set the capture bytecode */
+       capture_bytecode_count = lttng_trigger_get_capture_bytecode_count(trigger);
+       for (unsigned int i = 0; i < capture_bytecode_count; i++) {
+               const struct lttng_bytecode *capture_bytecode = lttng_trigger_get_capture_bytecode_at_index(trigger, i);
+               ret = kernctl_capture(event->fd, capture_bytecode);
+               if (ret < 0) {
+                       goto error;
+               }
+       }
+
+       err = kernctl_enable(event->fd);
+       if (err < 0) {
+               switch (-err) {
+               case EEXIST:
+                       ret = LTTNG_ERR_KERN_EVENT_EXIST;
+                       break;
+               default:
+                       PERROR("enable kernel trigger");
+                       ret = LTTNG_ERR_KERN_ENABLE_FAIL;
+                       break;
+               }
+               goto enable_error;
+       }
+
+       /* Add event to event list */
+       cds_list_add(&event->list, &kernel_tracer_token_list.head);
+
+       DBG("Trigger %s created (fd: %d)", kernel_trigger.name, event->fd);
+
+       return 0;
+
+add_callsite_error:
+enable_error:
+filter_error:
+       {
+               int closeret;
+
+               closeret = close(event->fd);
+               if (closeret) {
+                       PERROR("close event fd");
+               }
+       }
+free_event:
+       free(event);
+error:
+       return ret;
+}
+
+enum lttng_error_code kernel_update_tokens(void)
+{
+       enum lttng_error_code ret = LTTNG_OK;
+       enum lttng_trigger_status t_status;
+       struct ltt_kernel_token_event_rule *token_event_rule_element;
+       struct lttng_triggers *triggers;
+       unsigned int count;
+
+       /* TODO error handling */
+
+       /* Get list of token trigger from the notification thread here */
+       rcu_read_lock();
+       pthread_mutex_lock(&notification_trigger_tokens_ht_lock);
+       ret = notification_thread_command_get_tokens(notification_thread_handle, &triggers);
+       if (ret != LTTNG_OK) {
+               ret = -1;
+               goto end;
+       }
+
+       assert(triggers);
+
+       t_status = lttng_triggers_get_count(triggers, &count);
+       if (t_status != LTTNG_TRIGGER_STATUS_OK) {
+               ret = -1;
+               goto end;
+       }
+
+       for (unsigned int i = 0; i < count; i++) {
+               struct lttng_condition *condition;
+               struct lttng_event_rule *event_rule;
+               struct lttng_trigger *trigger;
+               struct ltt_kernel_token_event_rule *k_token;
+               const struct lttng_credentials *creds;
+               uint64_t token;
+
+               trigger = lttng_triggers_get_pointer_of_index(triggers, i);
+               assert(trigger);
+
+               /* TODO: error checking and type checking */
+               token = lttng_trigger_get_key(trigger);
+               condition = lttng_trigger_get_condition(trigger);
+               (void) lttng_condition_event_rule_get_rule_no_const(condition, &event_rule);
+
+               if (lttng_event_rule_get_domain_type(event_rule) != LTTNG_DOMAIN_KERNEL) {
+                       /* Skip ust related trigger */
+                       continue;
+               }
+
+               creds = lttng_trigger_get_credentials(trigger);
+               /* Iterate over all known token trigger */
+               k_token = trace_kernel_find_trigger_by_token(&kernel_tracer_token_list, token);
+               if (!k_token) {
+                       ret = kernel_create_token_event_rule(trigger, creds, token);
+                       if (ret < 0) {
+                               goto end;
+                       }
+               }
+       }
+
+       /* Remove all unknown trigger from the app
+        * TODO find a way better way then this, do it on the unregister command
+        * and be specific on the token to remove instead of going over all
+        * trigger known to the app. This is sub optimal.
+        */
+       cds_list_for_each_entry (token_event_rule_element, &kernel_tracer_token_list.head,
+                       list) {
+               uint64_t token;
+               bool found = false;
+
+               token = token_event_rule_element->token;
+
+       /*
+                * Check if the app event trigger still exists on the
+                * notification side.
+                * TODO: might want to change the backing data struct of the
+                * lttng_triggers object to allow quick lookup?
+                * For kernel mostly all of this can be removed once we delete
+                * on a per trigger basis.
+                */
+
+               for (unsigned int i = 0; i < count; i++) {
+                       struct lttng_trigger *trigger;
+                       uint64_t inner_token;
+
+                       trigger = lttng_triggers_get_pointer_of_index(
+                                       triggers, i);
+                       assert(trigger);
+
+                       inner_token = lttng_trigger_get_key(trigger);
+
+                       if (inner_token == token) {
+                               found = true;
+                               break;
+                       }
+               }
+
+               if (found) {
+                       /* Still valid */
+                       continue;
+               }
+
+               kernel_disable_token_event_rule(token_event_rule_element);
+               trace_kernel_destroy_token_event_rule(token_event_rule_element);
+       }
+end:
+       lttng_triggers_destroy(triggers);
+       rcu_read_unlock();
+       pthread_mutex_unlock(&notification_trigger_tokens_ht_lock);
+       return ret;
+
+}
+
+int kernel_get_notification_fd(void)
+{
+       return kernel_tracer_trigger_group_notification_fd;
+}
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