X-Git-Url: https://git.lttng.org/?a=blobdiff_plain;f=src%2Fbin%2Flttng-sessiond%2Fkernel.c;h=1fc36e33e9b45b1c7b941c3261f7c8ad0c07dfe9;hb=0a398bc4ce5e8f150e71cc7196162e677d571821;hp=c5fd30b7ead925f106cfe4d3c1164c6bc21fd5c8;hpb=2d97a0067600335f07eecb2c1d9ba68fc164583e;p=lttng-tools.git

diff --git a/src/bin/lttng-sessiond/kernel.c b/src/bin/lttng-sessiond/kernel.c
index c5fd30b7e..1fc36e33e 100644
--- a/src/bin/lttng-sessiond/kernel.c
+++ b/src/bin/lttng-sessiond/kernel.c
@@ -1,18 +1,8 @@
 /*
- * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
+ * Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca>
  *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License, version 2 only,
- * as published by the Free Software Foundation.
+ * SPDX-License-Identifier: GPL-2.0-only
  *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License along
- * with this program; if not, write to the Free Software Foundation, Inc.,
- * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
 #define _LGPL_SOURCE
@@ -29,6 +19,11 @@
 #include <common/kernel-ctl/kernel-ctl.h>
 #include <common/kernel-ctl/kernel-ioctl.h>
 #include <common/sessiond-comm/sessiond-comm.h>
+#include <common/tracker.h>
+#include <common/utils.h>
+#include <lttng/event.h>
+#include <lttng/lttng-error.h>
+#include <lttng/tracker.h>
 
 #include "lttng-sessiond.h"
 #include "lttng-syscall.h"
@@ -39,6 +34,7 @@
 #include "utils.h"
 #include "rotate.h"
 #include "modprobe.h"
+#include "tracker.h"
 
 /*
  * Key used to reference a channel between the sessiond and the consumer. This
@@ -234,7 +230,7 @@ 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;
@@ -271,8 +267,7 @@ 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);
@@ -296,7 +291,7 @@ 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;
@@ -342,7 +337,7 @@ 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);
@@ -363,29 +358,16 @@ 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;
@@ -398,7 +380,8 @@ 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;
@@ -407,8 +390,7 @@ 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("Failed to add callsite to ELF userspace probe.");
 			ret = LTTNG_ERR_KERN_ENABLE_FAIL;
 			goto end;
 		}
@@ -425,8 +407,8 @@ 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;
@@ -435,8 +417,7 @@ 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("Failed to add callsite to SDT userspace probe");
 				ret = LTTNG_ERR_KERN_ENABLE_FAIL;
 				free(offsets);
 				goto end;
@@ -453,6 +434,37 @@ 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)
+{
+	int ret;
+	const struct lttng_userspace_probe_location *location = NULL;
+
+	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("Failed to add callsite to userspace probe event '%s'",
+				ev->name);
+	}
+
+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.
@@ -522,7 +534,8 @@ 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;
 		}
@@ -679,277 +692,370 @@ error:
 	return ret;
 }
 
-static struct lttng_tracker_list *get_id_tracker_list(
+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_id **saved_ids;
-	ssize_t saved_ids_count;
+	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. */
-	saved_ids_count = lttng_tracker_id_get_list(tracker_list, &saved_ids);
-	if (saved_ids_count < 0) {
-		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,
-			    saved_ids_count) != LTTNG_OK) {
-		ERR("Error on tracker add error handling.\n");
-	}
 end:
-	lttng_tracker_ids_destroy(saved_ids, saved_ids_count);
-	free(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_id **saved_ids;
-	ssize_t saved_ids_count;
+	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;
+	/*
+	 * 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;
 	}
 
-	tracker_list = get_id_tracker_list(session, tracker_type);
-	if (!tracker_list) {
-		return LTTNG_ERR_INVALID;
+	tracker = _kernel_get_process_attr_tracker(session, process_attr);
+	if (!tracker) {
+		ret_code = LTTNG_ERR_INVALID;
+		goto end;
 	}
-	/* Save list for restore on error. */
-	saved_ids_count = lttng_tracker_id_get_list(tracker_list, &saved_ids);
-	if (saved_ids_count < 0) {
-		return LTTNG_ERR_INVALID;
+
+	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;
 	}
-	/* Remove from list. */
-	ret = lttng_tracker_list_remove(tracker_list, id);
-	if (ret != LTTNG_OK) {
+
+	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;
 	}
 
-	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;
-		}
+	kernel_wait_quiescent();
+
+	/* kern-ctl error handling */
+	switch (-ret) {
+	case 0:
+		ret_code = LTTNG_OK;
 		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;
-		}
+	case EINVAL:
+		ret_code = LTTNG_ERR_INVALID;
 		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;
-		}
+	case ENOMEM:
+		ret_code = LTTNG_ERR_NOMEM;
 		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;
-		}
+	case EEXIST:
+		ret_code = LTTNG_ERR_PROCESS_ATTR_EXISTS;
 		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;
+	default:
+		ret_code = LTTNG_ERR_UNK;
+		break;
+	}
+
+	/* 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:
+	return ret_code;
+}
+
+enum lttng_error_code kernel_process_attr_tracker_inclusion_set_remove_value(
+		struct ltt_kernel_session *session,
+		enum lttng_process_attr process_attr,
+		const struct process_attr_value *value)
+{
+	int ret, integral_value;
+	enum lttng_error_code ret_code;
+	struct process_attr_tracker *tracker;
+	enum process_attr_tracker_status status;
+
+	/*
+	 * 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_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;
+	}
+
+	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;
 	}
 
-	/* Error handling. */
+	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 = 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;
+	case ENOENT:
+		ret_code = LTTNG_ERR_PROCESS_ATTR_MISSING;
 		break;
 	default:
-		ret = LTTNG_ERR_UNK;
+		ret_code = LTTNG_ERR_UNK;
 		break;
 	}
 
-	if (lttng_tracker_id_set_list(tracker_list, saved_ids,
-			    saved_ids_count) != LTTNG_OK) {
-		ERR("Error on tracker remove error handling.\n");
+	/* 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:
-	lttng_tracker_ids_destroy(saved_ids, saved_ids_count);
-	free(saved_ids);
-	return ret;
-}
-
-/*
- * Called with session lock held.
- */
-ssize_t kernel_list_tracker_ids(enum lttng_tracker_type tracker_type,
-		struct ltt_kernel_session *session,
-		struct lttng_tracker_id ***_ids)
-{
-	struct lttng_tracker_list *tracker_list;
-
-	tracker_list = get_id_tracker_list(session, tracker_type);
-	if (!tracker_list) {
-		return -LTTNG_ERR_INVALID;
-	}
-	return lttng_tracker_id_get_list(tracker_list, _ids);
+	return ret_code;
 }
 
 /*
@@ -1552,16 +1658,10 @@ int kernel_syscall_mask(int chan_fd, char **syscall_mask, uint32_t *nr_bits)
 	return kernctl_syscall_mask(chan_fd, syscall_mask, nr_bits);
 }
 
-/*
- * Check for the support of the RING_BUFFER_SNAPSHOT_SAMPLE_POSITIONS via abi
- * version number.
- *
- * Return 1 on success, 0 when feature is not supported, negative value in case
- * of errors.
- */
-int kernel_supports_ring_buffer_snapshot_sample_positions(void)
+static
+int kernel_tracer_abi_greater_or_equal(unsigned int major, unsigned int minor)
 {
-	int ret = 0; // Not supported by default
+	int ret;
 	struct lttng_kernel_tracer_abi_version abi;
 
 	ret = kernctl_tracer_abi_version(kernel_tracer_fd, &abi);
@@ -1570,18 +1670,24 @@ int kernel_supports_ring_buffer_snapshot_sample_positions(void)
 		goto error;
 	}
 
+	ret = abi.major > major || (abi.major == major && abi.minor >= minor);
+error:
+	return ret;
+}
+
+/*
+ * Check for the support of the RING_BUFFER_SNAPSHOT_SAMPLE_POSITIONS via abi
+ * version number.
+ *
+ * Return 1 on success, 0 when feature is not supported, negative value in case
+ * of errors.
+ */
+int kernel_supports_ring_buffer_snapshot_sample_positions(void)
+{
 	/*
 	 * RING_BUFFER_SNAPSHOT_SAMPLE_POSITIONS was introduced in 2.3
 	 */
-	if (abi.major >= 2 && abi.minor >= 3) {
-		/* Supported */
-		ret = 1;
-	} else {
-		/* Not supported */
-		ret = 0;
-	}
-error:
-	return ret;
+	return kernel_tracer_abi_greater_or_equal(2, 3);
 }
 
 /*
@@ -1592,28 +1698,25 @@ error:
  */
 int kernel_supports_ring_buffer_packet_sequence_number(void)
 {
-	int ret = 0; // Not supported by default
-	struct lttng_kernel_tracer_abi_version abi;
-
-	ret = kernctl_tracer_abi_version(kernel_tracer_fd, &abi);
-	if (ret < 0) {
-		ERR("Failed to retrieve lttng-modules ABI version");
-		goto error;
-	}
-
 	/*
 	 * Packet sequence number was introduced in LTTng 2.8,
 	 * lttng-modules ABI 2.1.
 	 */
-	if (abi.major >= 2 && abi.minor >= 1) {
-		/* Supported */
-		ret = 1;
-	} else {
-		/* Not supported */
-		ret = 0;
-	}
-error:
-	return ret;
+	return kernel_tracer_abi_greater_or_equal(2, 1);
+}
+
+/*
+ * Check for the support of event notifiers via abi version number.
+ *
+ * Return 1 on success, 0 when feature is not supported, negative value in case
+ * of errors.
+ */
+int kernel_supports_event_notifiers(void)
+{
+	/*
+	 * Event notifiers were introduced in LTTng 2.13, lttng-modules ABI 2.6.
+	 */
+	return kernel_tracer_abi_greater_or_equal(2, 6);
 }
 
 /*
@@ -1645,7 +1748,7 @@ enum lttng_error_code kernel_rotate_session(struct ltt_session *session)
 			socket, node.node) {
 		struct ltt_kernel_channel *chan;
 
-                /* For each channel, ask the consumer to rotate it. */
+		/* For each channel, ask the consumer to rotate it. */
 		cds_list_for_each_entry(chan, &ksess->channel_list.head, list) {
 			DBG("Rotate kernel channel %" PRIu64 ", session %s",
 					chan->key, session->name);
@@ -1653,7 +1756,7 @@ 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;
 			}
 		}
@@ -1665,7 +1768,7 @@ 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;
 		}
 	}