X-Git-Url: https://git.liburcu.org/?a=blobdiff_plain;f=src%2Flib%2Flttng-ctl%2Flttng-ctl.c;h=fd5d9e3d66eb9dbddbafa8490da95cf1ab5f21d5;hb=c2afda67713866265294d11c72deca6edba05969;hp=b57be223a73afce55723c858c66a5aedfa245b24;hpb=2c2de71ef6dae09fa1a61f02051b68f60b0a1750;p=lttng-tools.git

diff --git a/src/lib/lttng-ctl/lttng-ctl.c b/src/lib/lttng-ctl/lttng-ctl.c
index b57be223a..fd5d9e3d6 100644
--- a/src/lib/lttng-ctl/lttng-ctl.c
+++ b/src/lib/lttng-ctl/lttng-ctl.c
@@ -3,21 +3,11 @@
  *
  * Linux Trace Toolkit Control Library
  *
- * Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca>
- * Copyright (C) 2016 - Jérémie Galarneau <jeremie.galarneau@efficios.com>
+ * Copyright (C) 2011 EfficiOS Inc.
+ * Copyright (C) 2016 Jérémie Galarneau <jeremie.galarneau@efficios.com>
  *
- * This library is free software; you can redistribute it and/or modify it
- * under the terms of the GNU Lesser General Public License, version 2.1 only,
- * as published by the Free Software Foundation.
+ * SPDX-License-Identifier: LGPL-2.1-only
  *
- * This library 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
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public License
- * along with this library; if not, write to the Free Software Foundation,
- * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
 #define _LGPL_SOURCE
@@ -26,22 +16,30 @@
 #include <errno.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <stdint.h>
 #include <string.h>
 #include <unistd.h>
 
+#include <common/buffer-view.h>
 #include <common/common.h>
 #include <common/compat/string.h>
 #include <common/defaults.h>
+#include <common/dynamic-array.h>
+#include <common/dynamic-buffer.h>
+#include <common/macros.h>
 #include <common/sessiond-comm/sessiond-comm.h>
+#include <common/tracker.h>
 #include <common/uri.h>
 #include <common/utils.h>
-#include <common/dynamic-buffer.h>
-#include <lttng/lttng.h>
-#include <lttng/health-internal.h>
-#include <lttng/trigger/trigger-internal.h>
-#include <lttng/endpoint.h>
 #include <lttng/channel-internal.h>
+#include <lttng/destruction-handle.h>
+#include <lttng/endpoint.h>
 #include <lttng/event-internal.h>
+#include <lttng/health-internal.h>
+#include <lttng/lttng.h>
+#include <lttng/session-descriptor-internal.h>
+#include <lttng/session-internal.h>
+#include <lttng/trigger/trigger-internal.h>
 #include <lttng/userspace-probe-internal.h>
 
 #include "filter/filter-ast.h"
@@ -64,9 +62,16 @@ do {								\
 } while (0)
 #endif
 
+#define COPY_DOMAIN_PACKED(dst, src)				\
+do {								\
+	struct lttng_domain _tmp_domain;			\
+								\
+	lttng_ctl_copy_lttng_domain(&_tmp_domain, &src);	\
+	dst = _tmp_domain;					\
+} while (0)
 
 /* Socket to session daemon for communication */
-static int sessiond_socket;
+static int sessiond_socket = -1;
 static char sessiond_sock_path[PATH_MAX];
 
 /* Variables */
@@ -84,21 +89,6 @@ int lttng_opt_quiet;
 int lttng_opt_verbose;
 int lttng_opt_mi;
 
-/*
- * Copy string from src to dst and enforce null terminated byte.
- */
-LTTNG_HIDDEN
-void lttng_ctl_copy_string(char *dst, const char *src, size_t len)
-{
-	if (src && dst) {
-		strncpy(dst, src, len);
-		/* Enforce the NULL terminated byte */
-		dst[len - 1] = '\0';
-	} else if (dst) {
-		dst[0] = '\0';
-	}
-}
-
 /*
  * Copy domain to lttcomm_session_msg domain.
  *
@@ -241,15 +231,13 @@ end:
 LTTNG_HIDDEN
 int lttng_check_tracing_group(void)
 {
-	struct group *grp_tracing;	/* no free(). See getgrnam(3) */
-	gid_t *grp_list;
+	gid_t *grp_list, tracing_gid;
 	int grp_list_size, grp_id, i;
 	int ret = -1;
 	const char *grp_name = tracing_group;
 
 	/* Get GID of group 'tracing' */
-	grp_tracing = getgrnam(grp_name);
-	if (!grp_tracing) {
+	if (utils_get_group_id(grp_name, false, &tracing_gid)) {
 		/* If grp_tracing is NULL, the group does not exist. */
 		goto end;
 	}
@@ -274,7 +262,7 @@ int lttng_check_tracing_group(void)
 	}
 
 	for (i = 0; i < grp_list_size; i++) {
-		if (grp_list[i] == grp_tracing->gr_gid) {
+		if (grp_list[i] == tracing_gid) {
 			ret = 1;
 			break;
 		}
@@ -287,6 +275,67 @@ end:
 	return ret;
 }
 
+static enum lttng_error_code check_enough_available_memory(
+		uint64_t num_bytes_requested_per_cpu)
+{
+	int ret;
+	long num_cpu;
+	uint64_t best_mem_info;
+	uint64_t num_bytes_requested_total;
+
+	/*
+	 * Get the number of CPU currently online to compute the amount of
+	 * memory needed to create a buffer for every CPU.
+	 */
+	num_cpu = sysconf(_SC_NPROCESSORS_ONLN);
+	if (num_cpu == -1) {
+		ret = LTTNG_ERR_FATAL;
+		goto end;
+	}
+
+	if (num_bytes_requested_per_cpu > UINT64_MAX / (uint64_t) num_cpu) {
+		/* Overflow */
+		ret = LTTNG_ERR_OVERFLOW;
+		goto end;
+	}
+
+	num_bytes_requested_total =
+			num_bytes_requested_per_cpu * (uint64_t) num_cpu;
+
+	/*
+	 * Try to get the `MemAvail` field of `/proc/meminfo`. This is the most
+	 * reliable estimate we can get but it is only exposed by the kernel
+	 * since 3.14. (See Linux kernel commit:
+	 * 34e431b0ae398fc54ea69ff85ec700722c9da773)
+	 */
+	ret = utils_get_memory_available(&best_mem_info);
+	if (ret >= 0) {
+		goto success;
+	}
+
+	/*
+	 * As a backup plan, use `MemTotal` field of `/proc/meminfo`. This
+	 * is a sanity check for obvious user error.
+	 */
+	ret = utils_get_memory_total(&best_mem_info);
+	if (ret >= 0) {
+		goto success;
+	}
+
+	/* No valid source of information. */
+	ret = LTTNG_ERR_NOMEM;
+	goto end;
+
+success:
+	if (best_mem_info >= num_bytes_requested_total) {
+		ret = LTTNG_OK;
+	} else {
+		ret = LTTNG_ERR_NOMEM;
+	}
+end:
+	return ret;
+}
+
 /*
  * Try connect to session daemon with sock_path.
  *
@@ -339,9 +388,14 @@ static int set_session_daemon_path(void)
 		in_tgroup = lttng_check_tracing_group();
 	}
 
-	if ((uid == 0) || in_tgroup) {
-		lttng_ctl_copy_string(sessiond_sock_path,
-				DEFAULT_GLOBAL_CLIENT_UNIX_SOCK, sizeof(sessiond_sock_path));
+	if ((uid == 0) || in_tgroup == 1) {
+		const int ret = lttng_strncpy(sessiond_sock_path,
+				DEFAULT_GLOBAL_CLIENT_UNIX_SOCK,
+				sizeof(sessiond_sock_path));
+
+		if (ret) {
+			goto error;
+		}
 	}
 
 	if (uid != 0) {
@@ -379,17 +433,12 @@ error:
 /*
  * Connect to the LTTng session daemon.
  *
- * On success, return 0. On error, return -1.
+ * On success, return the socket's file descriptor. On error, return -1.
  */
-static int connect_sessiond(void)
+LTTNG_HIDDEN int connect_sessiond(void)
 {
 	int ret;
 
-	/* Don't try to connect if already connected. */
-	if (connected) {
-		return 0;
-	}
-
 	ret = set_session_daemon_path();
 	if (ret < 0) {
 		goto error;
@@ -401,15 +450,18 @@ static int connect_sessiond(void)
 		goto error;
 	}
 
-	sessiond_socket = ret;
-	connected = 1;
-
-	return 0;
+	return ret;
 
 error:
 	return -1;
 }
 
+static void reset_global_sessiond_connection_state(void)
+{
+	sessiond_socket = -1;
+	connected = 0;
+}
+
 /*
  *  Clean disconnect from the session daemon.
  *
@@ -421,8 +473,7 @@ static int disconnect_sessiond(void)
 
 	if (connected) {
 		ret = lttcomm_close_unix_sock(sessiond_socket);
-		sessiond_socket = 0;
-		connected = 0;
+		reset_global_sessiond_connection_state();
 	}
 
 	return ret;
@@ -497,6 +548,9 @@ int lttng_ctl_ask_sessiond_fds_varlen(struct lttcomm_session_msg *lsm,
 	if (ret < 0) {
 		ret = -LTTNG_ERR_NO_SESSIOND;
 		goto end;
+	} else {
+		sessiond_socket = ret;
+		connected = 1;
 	}
 
 	/* Send command to session daemon */
@@ -561,6 +615,7 @@ end:
 struct lttng_handle *lttng_create_handle(const char *session_name,
 		struct lttng_domain *domain)
 {
+	int ret;
 	struct lttng_handle *handle = NULL;
 
 	handle = zmalloc(sizeof(struct lttng_handle));
@@ -570,8 +625,11 @@ struct lttng_handle *lttng_create_handle(const char *session_name,
 	}
 
 	/* Copy session name */
-	lttng_ctl_copy_string(handle->session_name, session_name,
-			sizeof(handle->session_name));
+	ret = lttng_strncpy(handle->session_name, session_name ? : "",
+			    sizeof(handle->session_name));
+	if (ret) {
+		goto error;
+	}
 
 	/* Copy lttng domain or leave initialized to 0. */
 	if (domain) {
@@ -580,6 +638,9 @@ struct lttng_handle *lttng_create_handle(const char *session_name,
 
 end:
 	return handle;
+error:
+	free(handle);
+	return NULL;
 }
 
 /*
@@ -598,22 +659,35 @@ void lttng_destroy_handle(struct lttng_handle *handle)
 int lttng_register_consumer(struct lttng_handle *handle,
 		const char *socket_path)
 {
+	int ret;
 	struct lttcomm_session_msg lsm;
 
 	if (handle == NULL || socket_path == NULL) {
-		return -LTTNG_ERR_INVALID;
+		ret = -LTTNG_ERR_INVALID;
+		goto end;
 	}
 
 	memset(&lsm, 0, sizeof(lsm));
 	lsm.cmd_type = LTTNG_REGISTER_CONSUMER;
-	lttng_ctl_copy_string(lsm.session.name, handle->session_name,
+	ret = lttng_strncpy(lsm.session.name, handle->session_name,
 			sizeof(lsm.session.name));
-	lttng_ctl_copy_lttng_domain(&lsm.domain, &handle->domain);
+	if (ret) {
+		ret = -LTTNG_ERR_INVALID;
+		goto end;
+	}
 
-	lttng_ctl_copy_string(lsm.u.reg.path, socket_path,
-			sizeof(lsm.u.reg.path));
+	COPY_DOMAIN_PACKED(lsm.domain, handle->domain);
+
+	ret = lttng_strncpy(lsm.u.reg.path, socket_path,
+			    sizeof(lsm.u.reg.path));
+	if (ret) {
+		ret = -LTTNG_ERR_INVALID;
+		goto end;
+	}
 
-	return lttng_ctl_ask_sessiond(&lsm, NULL);
+	ret = lttng_ctl_ask_sessiond(&lsm, NULL);
+end:
+	return ret;
 }
 
 /*
@@ -623,19 +697,27 @@ int lttng_register_consumer(struct lttng_handle *handle,
  */
 int lttng_start_tracing(const char *session_name)
 {
+	int ret;
 	struct lttcomm_session_msg lsm;
 
 	if (session_name == NULL) {
-		return -LTTNG_ERR_INVALID;
+		ret = -LTTNG_ERR_INVALID;
+		goto end;
 	}
 
 	memset(&lsm, 0, sizeof(lsm));
 	lsm.cmd_type = LTTNG_START_TRACE;
 
-	lttng_ctl_copy_string(lsm.session.name, session_name,
-			sizeof(lsm.session.name));
+	ret = lttng_strncpy(lsm.session.name, session_name,
+			    sizeof(lsm.session.name));
+	if (ret) {
+		ret = -LTTNG_ERR_INVALID;
+		goto end;
+	}
 
-	return lttng_ctl_ask_sessiond(&lsm, NULL);
+	ret = lttng_ctl_ask_sessiond(&lsm, NULL);
+end:
+	return ret;
 }
 
 /*
@@ -647,14 +729,19 @@ static int _lttng_stop_tracing(const char *session_name, int wait)
 	struct lttcomm_session_msg lsm;
 
 	if (session_name == NULL) {
-		return -LTTNG_ERR_INVALID;
+		ret = -LTTNG_ERR_INVALID;
+		goto error;
 	}
 
 	memset(&lsm, 0, sizeof(lsm));
 	lsm.cmd_type = LTTNG_STOP_TRACE;
 
-	lttng_ctl_copy_string(lsm.session.name, session_name,
-			sizeof(lsm.session.name));
+	ret = lttng_strncpy(lsm.session.name, session_name,
+			    sizeof(lsm.session.name));
+	if (ret) {
+		ret = -LTTNG_ERR_INVALID;
+		goto error;
+	}
 
 	ret = lttng_ctl_ask_sessiond(&lsm, NULL);
 	if (ret < 0 && ret != -LTTNG_ERR_TRACE_ALREADY_STOPPED) {
@@ -679,7 +766,7 @@ static int _lttng_stop_tracing(const char *session_name, int wait)
 		 * call returned value indicates availability.
 		 */
 		if (data_ret) {
-			usleep(DEFAULT_DATA_AVAILABILITY_WAIT_TIME);
+			usleep(DEFAULT_DATA_AVAILABILITY_WAIT_TIME_US);
 		}
 	} while (data_ret != 0);
 
@@ -717,9 +804,10 @@ int lttng_add_context(struct lttng_handle *handle,
 		const char *channel_name)
 {
 	int ret;
-	size_t len = 0;
-	char *buf = NULL;
 	struct lttcomm_session_msg lsm;
+	struct lttng_dynamic_buffer buffer;
+
+	lttng_dynamic_buffer_init(&buffer);
 
 	/* Safety check. Both are mandatory. */
 	if (handle == NULL || ctx == NULL) {
@@ -731,67 +819,33 @@ int lttng_add_context(struct lttng_handle *handle,
 	lsm.cmd_type = LTTNG_ADD_CONTEXT;
 
 	/* If no channel name, send empty string. */
-	if (channel_name == NULL) {
-		lttng_ctl_copy_string(lsm.u.context.channel_name, "",
-				sizeof(lsm.u.context.channel_name));
-	} else {
-		lttng_ctl_copy_string(lsm.u.context.channel_name, channel_name,
-				sizeof(lsm.u.context.channel_name));
+	ret = lttng_strncpy(lsm.u.context.channel_name, channel_name ?: "",
+			sizeof(lsm.u.context.channel_name));
+	if (ret) {
+		ret = -LTTNG_ERR_INVALID;
+		goto end;
 	}
 
-	lttng_ctl_copy_lttng_domain(&lsm.domain, &handle->domain);
-	lttng_ctl_copy_string(lsm.session.name, handle->session_name,
+	COPY_DOMAIN_PACKED(lsm.domain, handle->domain);
+	ret = lttng_strncpy(lsm.session.name, handle->session_name,
 			sizeof(lsm.session.name));
-
-	if (ctx->ctx == LTTNG_EVENT_CONTEXT_APP_CONTEXT) {
-		size_t provider_len, ctx_len;
-		const char *provider_name = ctx->u.app_ctx.provider_name;
-		const char *ctx_name = ctx->u.app_ctx.ctx_name;
-
-		if (!provider_name || !ctx_name) {
-			ret = -LTTNG_ERR_INVALID;
-			goto end;
-		}
-
-		provider_len = strlen(provider_name);
-		if (provider_len == 0) {
-			ret = -LTTNG_ERR_INVALID;
-			goto end;
-		}
-		lsm.u.context.provider_name_len = provider_len;
-
-		ctx_len = strlen(ctx_name);
-		if (ctx_len == 0) {
-			ret = -LTTNG_ERR_INVALID;
-			goto end;
-		}
-		lsm.u.context.context_name_len = ctx_len;
-
-		len = provider_len + ctx_len;
-		buf = zmalloc(len);
-		if (!buf) {
-			ret = -LTTNG_ERR_NOMEM;
-			goto end;
-		}
-
-		memcpy(buf, provider_name, provider_len);
-		memcpy(buf + provider_len, ctx_name, ctx_len);
+	if (ret) {
+		ret = -LTTNG_ERR_INVALID;
+		goto end;
 	}
-	memcpy(&lsm.u.context.ctx, ctx, sizeof(struct lttng_event_context));
 
-	if (ctx->ctx == LTTNG_EVENT_CONTEXT_APP_CONTEXT) {
-		/*
-		 * Don't leak application addresses to the sessiond.
-		 * This is only necessary when ctx is for an app ctx otherwise
-		 * the values inside the union (type & config) are overwritten.
-		 */
-		lsm.u.context.ctx.u.app_ctx.provider_name = NULL;
-		lsm.u.context.ctx.u.app_ctx.ctx_name = NULL;
+	ret = lttng_event_context_serialize(ctx, &buffer);
+	if (ret) {
+		ret = -LTTNG_ERR_INVALID;
+		goto end;
 	}
 
-	ret = lttng_ctl_ask_sessiond_varlen_no_cmd_header(&lsm, buf, len, NULL);
+	lsm.u.context.length = buffer.size;
+
+	ret = lttng_ctl_ask_sessiond_varlen_no_cmd_header(
+			&lsm, buffer.data, buffer.size, NULL);
 end:
-	free(buf);
+	lttng_dynamic_buffer_reset(&buffer);
 	return ret;
 }
 
@@ -853,7 +907,7 @@ static char *set_agent_filter(const char *filter, struct lttng_event *ev)
 
 	/* Add loglevel filtering if any for the JUL domain. */
 	if (ev->loglevel_type != LTTNG_EVENT_LOGLEVEL_ALL) {
-		char *op;
+		const char *op;
 
 		if (ev->loglevel_type == LTTNG_EVENT_LOGLEVEL_RANGE) {
 			op = ">=";
@@ -895,14 +949,14 @@ error:
  * Return 0 on success else a LTTNG_ERR_* code and ctxp is untouched.
  */
 static int generate_filter(char *filter_expression,
-		struct lttcomm_session_msg *lsm, struct filter_parser_ctx **ctxp)
+		size_t *bytecode_len,
+		struct filter_parser_ctx **ctxp)
 {
 	int ret;
 	struct filter_parser_ctx *ctx = NULL;
 	FILE *fmem = NULL;
 
 	assert(filter_expression);
-	assert(lsm);
 	assert(ctxp);
 
 	/*
@@ -991,9 +1045,8 @@ static int generate_filter(char *filter_expression,
 	dbg_printf("Size of bytecode generated: %u bytes.\n",
 			bytecode_get_len(&ctx->bytecode->b));
 
-	lsm->u.enable.bytecode_len = sizeof(ctx->bytecode->b)
-		+ bytecode_get_len(&ctx->bytecode->b);
-	lsm->u.enable.expression_len = strlen(filter_expression) + 1;
+	*bytecode_len = sizeof(ctx->bytecode->b) +
+			bytecode_get_len(&ctx->bytecode->b);
 
 	/* No need to keep the memory stream. */
 	if (fclose(fmem) != 0) {
@@ -1029,12 +1082,17 @@ int lttng_enable_event_with_exclusions(struct lttng_handle *handle,
 {
 	struct lttcomm_session_msg lsm;
 	struct lttng_dynamic_buffer send_buffer;
-	int ret = 0, i, fd_to_send = -1;
+	int ret = 0, fd_to_send = -1;
 	bool send_fd = false;
 	unsigned int free_filter_expression = 0;
 	struct filter_parser_ctx *ctx = NULL;
+	size_t bytecode_len = 0;
 
-	memset(&send_buffer, 0, sizeof(send_buffer));
+	/*
+	 * We have either a filter or some exclusions, so we need to set up
+	 * a variable-length memory block from where to send the data.
+	 */
+	lttng_dynamic_buffer_init(&send_buffer);
 
 	/*
 	 * Cast as non-const since we may replace the filter expression
@@ -1058,38 +1116,12 @@ int lttng_enable_event_with_exclusions(struct lttng_handle *handle,
 		goto error;
 	}
 
-	memset(&lsm, 0, sizeof(lsm));
-
-	/* If no channel name, send empty string. */
-	if (channel_name == NULL) {
-		lttng_ctl_copy_string(lsm.u.enable.channel_name, "",
-				sizeof(lsm.u.enable.channel_name));
-	} else {
-		lttng_ctl_copy_string(lsm.u.enable.channel_name, channel_name,
-				sizeof(lsm.u.enable.channel_name));
-	}
-
-	lsm.cmd_type = LTTNG_ENABLE_EVENT;
 	if (ev->name[0] == '\0') {
-		/* Enable all events */
-		lttng_ctl_copy_string(ev->name, "*", sizeof(ev->name));
+		/* Enable all events. */
+		ret = lttng_strncpy(ev->name, "*", sizeof(ev->name));
+		assert(ret == 0);
 	}
 
-	lttng_ctl_copy_lttng_domain(&lsm.domain, &handle->domain);
-	/* FIXME: copying non-packed struct to packed struct. */
-	memcpy(&lsm.u.enable.event, ev, sizeof(lsm.u.enable.event));
-
-	lttng_ctl_copy_string(lsm.session.name, handle->session_name,
-			sizeof(lsm.session.name));
-	lsm.u.enable.exclusion_count = exclusion_count;
-	lsm.u.enable.bytecode_len = 0;
-
-	/*
-	 * We have either a filter or some exclusions, so we need to set up
-	 * a variable-length memory block from where to send the data.
-	 */
-	lttng_dynamic_buffer_init(&send_buffer);
-
 	/* Parse filter expression. */
 	if (filter_expression != NULL || handle->domain.type == LTTNG_DOMAIN_JUL
 			|| handle->domain.type == LTTNG_DOMAIN_LOG4J
@@ -1099,7 +1131,7 @@ int lttng_enable_event_with_exclusions(struct lttng_handle *handle,
 				handle->domain.type == LTTNG_DOMAIN_PYTHON) {
 			char *agent_filter;
 
-			/* Setup JUL filter if needed. */
+			/* Setup agent filter if needed. */
 			agent_filter = set_agent_filter(filter_expression, ev);
 			if (!agent_filter) {
 				if (!filter_expression) {
@@ -1107,7 +1139,7 @@ int lttng_enable_event_with_exclusions(struct lttng_handle *handle,
 					 * No JUL and no filter, just skip
 					 * everything below.
 					 */
-					goto ask_sessiond;
+					goto serialize;
 				}
 			} else {
 				/*
@@ -1120,96 +1152,74 @@ int lttng_enable_event_with_exclusions(struct lttng_handle *handle,
 			}
 		}
 
-		ret = generate_filter(filter_expression, &lsm, &ctx);
+		if (strnlen(filter_expression, LTTNG_FILTER_MAX_LEN) ==
+				LTTNG_FILTER_MAX_LEN) {
+			ret = -LTTNG_ERR_FILTER_INVAL;
+			goto error;
+		}
+
+		ret = generate_filter(filter_expression, &bytecode_len, &ctx);
 		if (ret) {
-			goto filter_error;
+			goto error;
+		}
+
+		if (bytecode_len > LTTNG_FILTER_MAX_LEN) {
+			ret = -LTTNG_ERR_FILTER_INVAL;
+			goto error;
 		}
 	}
 
-	ret = lttng_dynamic_buffer_set_capacity(&send_buffer,
-			lsm.u.enable.bytecode_len
-			+ lsm.u.enable.expression_len
-			+ LTTNG_SYMBOL_NAME_LEN * exclusion_count);
+serialize:
+	ret = lttng_event_serialize(ev, exclusion_count, exclusion_list,
+			filter_expression, bytecode_len,
+			ctx && (bytecode_len != 0) ? &ctx->bytecode->b : NULL,
+			&send_buffer, &fd_to_send);
 	if (ret) {
-		ret = -LTTNG_ERR_EXCLUSION_NOMEM;
-		goto mem_error;
+		goto error;
 	}
 
-	/* Put exclusion names first in the data. */
-	for (i = 0; i < exclusion_count; i++) {
-		size_t exclusion_len;
+	if (fd_to_send >= 0) {
+		send_fd = true;
+	}
 
-		exclusion_len = lttng_strnlen(*(exclusion_list + i),
-				LTTNG_SYMBOL_NAME_LEN);
-		if (exclusion_len == LTTNG_SYMBOL_NAME_LEN) {
-			/* Exclusion is not NULL-terminated. */
-			ret = -LTTNG_ERR_INVALID;
-			goto mem_error;
-		}
+	/* Prepare the command header */
+	memset(&lsm, 0, sizeof(lsm));
+	lsm.cmd_type = LTTNG_ENABLE_EVENT;
 
-		ret = lttng_dynamic_buffer_append(&send_buffer,
-				*(exclusion_list + i),
-				LTTNG_SYMBOL_NAME_LEN);
-		if (ret) {
-			goto mem_error;
-		}
+	/* If no channel name, send empty string. */
+	ret = lttng_strncpy(lsm.u.enable.channel_name, channel_name ?: "",
+			sizeof(lsm.u.enable.channel_name));
+	if (ret) {
+		ret = -LTTNG_ERR_INVALID;
+		goto error;
 	}
 
-	/* Add filter expression next. */
-	if (filter_expression) {
-		ret = lttng_dynamic_buffer_append(&send_buffer,
-				filter_expression, lsm.u.enable.expression_len);
-		if (ret) {
-			goto mem_error;
-		}
-	}
-	/* Add filter bytecode next. */
-	if (ctx && lsm.u.enable.bytecode_len != 0) {
-		ret = lttng_dynamic_buffer_append(&send_buffer,
-				&ctx->bytecode->b, lsm.u.enable.bytecode_len);
-		if (ret) {
-			goto mem_error;
-		}
-	}
-	if (ev->extended.ptr) {
-		struct lttng_event_extended *ev_ext =
-			(struct lttng_event_extended *) ev->extended.ptr;
-
-		if (ev_ext->probe_location) {
-			/*
-			 * lttng_userspace_probe_location_serialize returns the
-			 * number of bytes that was appended to the buffer.
-			 */
-			ret = lttng_userspace_probe_location_serialize(
-				ev_ext->probe_location, &send_buffer,
-				&fd_to_send);
-			if (ret < 0) {
-				goto mem_error;
-			}
+	/* Domain */
+	COPY_DOMAIN_PACKED(lsm.domain, handle->domain);
 
-			send_fd = fd_to_send >= 0;
-			/*
-			 * Set the size of the userspace probe location element
-			 * of the buffer so that the receiving side knows where
-			 * to split it.
-			 */
-			lsm.u.enable.userspace_probe_location_len = ret;
-		}
+	/* Session name */
+	ret = lttng_strncpy(lsm.session.name, handle->session_name,
+			sizeof(lsm.session.name));
+	if (ret) {
+		ret = -LTTNG_ERR_INVALID;
+		goto error;
 	}
 
+	/* Length of the serialized event */
+	lsm.u.enable.length = (uint32_t) send_buffer.size;
+
 	ret = lttng_ctl_ask_sessiond_fds_varlen(&lsm,
 			send_fd ? &fd_to_send : NULL,
 			send_fd ? 1 : 0,
 			send_buffer.size ? send_buffer.data : NULL,
 			send_buffer.size, NULL, NULL, 0);
-
-mem_error:
+error:
 	if (filter_expression && ctx) {
 		filter_bytecode_free(ctx);
 		filter_ir_free(ctx);
 		filter_parser_ctx_free(ctx);
 	}
-filter_error:
+
 	if (free_filter_expression) {
 		/*
 		 * The filter expression has been replaced and must be freed as
@@ -1218,16 +1228,8 @@ filter_error:
 		 */
 		free(filter_expression);
 	}
-error:
-	/*
-	 * Return directly to the caller and don't ask the sessiond since
-	 * something went wrong in the parsing of data above.
-	 */
-	lttng_dynamic_buffer_reset(&send_buffer);
-	return ret;
 
-ask_sessiond:
-	ret = lttng_ctl_ask_sessiond(&lsm, NULL);
+	lttng_dynamic_buffer_reset(&send_buffer);
 	return ret;
 }
 
@@ -1236,10 +1238,13 @@ int lttng_disable_event_ext(struct lttng_handle *handle,
 		const char *original_filter_expression)
 {
 	struct lttcomm_session_msg lsm;
-	char *varlen_data;
+	struct lttng_dynamic_buffer buf;
 	int ret = 0;
 	unsigned int free_filter_expression = 0;
 	struct filter_parser_ctx *ctx = NULL;
+	size_t bytecode_len = 0;
+	int fd_to_send = -1;
+	bool send_fd = false;
 	/*
 	 * Cast as non-const since we may replace the filter expression
 	 * by a dynamically allocated string. Otherwise, the original
@@ -1247,6 +1252,8 @@ int lttng_disable_event_ext(struct lttng_handle *handle,
 	 */
 	char *filter_expression = (char *) original_filter_expression;
 
+	lttng_dynamic_buffer_init(&buf);
+
 	if (handle == NULL || ev == NULL) {
 		ret = -LTTNG_ERR_INVALID;
 		goto error;
@@ -1262,44 +1269,6 @@ int lttng_disable_event_ext(struct lttng_handle *handle,
 		goto error;
 	}
 
-	memset(&lsm, 0, sizeof(lsm));
-
-	/* If no channel name, send empty string. */
-	if (channel_name == NULL) {
-		lttng_ctl_copy_string(lsm.u.disable.channel_name, "",
-				sizeof(lsm.u.disable.channel_name));
-	} else {
-		lttng_ctl_copy_string(lsm.u.disable.channel_name, channel_name,
-				sizeof(lsm.u.disable.channel_name));
-	}
-
-	lsm.cmd_type = LTTNG_DISABLE_EVENT;
-
-	lttng_ctl_copy_lttng_domain(&lsm.domain, &handle->domain);
-	/* FIXME: copying non-packed struct to packed struct. */
-	memcpy(&lsm.u.disable.event, ev, sizeof(lsm.u.disable.event));
-
-	lttng_ctl_copy_string(lsm.session.name, handle->session_name,
-			sizeof(lsm.session.name));
-	lsm.u.disable.bytecode_len = 0;
-
-	/*
-	 * For the JUL domain, a filter is enforced except for the
-	 * disable all event. This is done to avoid having the event in
-	 * all sessions thus filtering by logger name.
-	 */
-	if (filter_expression == NULL &&
-			(handle->domain.type != LTTNG_DOMAIN_JUL &&
-				handle->domain.type != LTTNG_DOMAIN_LOG4J &&
-				handle->domain.type != LTTNG_DOMAIN_PYTHON)) {
-		goto ask_sessiond;
-	}
-
-	/*
-	 * We have a filter, so we need to set up a variable-length
-	 * memory block from where to send the data.
-	 */
-
 	/* Parse filter expression */
 	if (filter_expression != NULL || handle->domain.type == LTTNG_DOMAIN_JUL
 			|| handle->domain.type == LTTNG_DOMAIN_LOG4J
@@ -1309,7 +1278,7 @@ int lttng_disable_event_ext(struct lttng_handle *handle,
 				handle->domain.type == LTTNG_DOMAIN_PYTHON) {
 			char *agent_filter;
 
-			/* Setup JUL filter if needed. */
+			/* Setup agent filter if needed. */
 			agent_filter = set_agent_filter(filter_expression, ev);
 			if (!agent_filter) {
 				if (!filter_expression) {
@@ -1317,7 +1286,7 @@ int lttng_disable_event_ext(struct lttng_handle *handle,
 					 * No JUL and no filter, just skip
 					 * everything below.
 					 */
-					goto ask_sessiond;
+					goto serialize;
 				}
 			} else {
 				/*
@@ -1330,44 +1299,63 @@ int lttng_disable_event_ext(struct lttng_handle *handle,
 			}
 		}
 
-		ret = generate_filter(filter_expression, &lsm, &ctx);
+		ret = generate_filter(filter_expression, &bytecode_len, &ctx);
 		if (ret) {
-			goto filter_error;
+			ret = -1;
+			goto error;
 		}
 	}
 
-	varlen_data = zmalloc(lsm.u.disable.bytecode_len
-			+ lsm.u.disable.expression_len);
-	if (!varlen_data) {
-		ret = -LTTNG_ERR_EXCLUSION_NOMEM;
-		goto mem_error;
+serialize:
+	ret = lttng_event_serialize(ev, 0, NULL, filter_expression,
+			bytecode_len,
+			ctx && (bytecode_len != 0) ? &ctx->bytecode->b : NULL,
+			&buf, &fd_to_send);
+	if (ret) {
+		ret = -1;
+		goto error;
+	}
+
+	if (fd_to_send >= 0) {
+		send_fd = true;
 	}
 
-	/* Add filter expression. */
-	if (lsm.u.disable.expression_len != 0) {
-		memcpy(varlen_data,
-			filter_expression,
-			lsm.u.disable.expression_len);
+	/* Prepare command header */
+	memset(&lsm, 0, sizeof(lsm));
+	lsm.cmd_type = LTTNG_DISABLE_EVENT;
+
+	/* If no channel name, send empty string. */
+	ret = lttng_strncpy(lsm.u.disable.channel_name, channel_name ?: "",
+			sizeof(lsm.u.disable.channel_name));
+	if (ret) {
+		ret = -LTTNG_ERR_INVALID;
+		goto error;
 	}
-	/* Add filter bytecode next. */
-	if (ctx && lsm.u.disable.bytecode_len != 0) {
-		memcpy(varlen_data
-			+ lsm.u.disable.expression_len,
-			&ctx->bytecode->b,
-			lsm.u.disable.bytecode_len);
+	/* Domain */
+	COPY_DOMAIN_PACKED(lsm.domain, handle->domain);
+
+	/* Session name */
+	ret = lttng_strncpy(lsm.session.name, handle->session_name,
+			sizeof(lsm.session.name));
+	if (ret) {
+		ret = -LTTNG_ERR_INVALID;
+		goto error;
 	}
 
-	ret = lttng_ctl_ask_sessiond_varlen_no_cmd_header(&lsm, varlen_data,
-			lsm.u.disable.bytecode_len + lsm.u.disable.expression_len, NULL);
-	free(varlen_data);
+	/* Length of the serialized event */
+	lsm.u.disable.length = (uint32_t) buf.size;
+
+	ret = lttng_ctl_ask_sessiond_fds_varlen(&lsm,
+			send_fd ? &fd_to_send : NULL, send_fd ? 1 : 0,
+			buf.size ? buf.data : NULL, buf.size, NULL, NULL, 0);
 
-mem_error:
+error:
 	if (filter_expression && ctx) {
 		filter_bytecode_free(ctx);
 		filter_ir_free(ctx);
 		filter_parser_ctx_free(ctx);
 	}
-filter_error:
+
 	if (free_filter_expression) {
 		/*
 		 * The filter expression has been replaced and must be freed as
@@ -1376,15 +1364,8 @@ filter_error:
 		 */
 		free(filter_expression);
 	}
-error:
-	/*
-	 * Return directly to the caller and don't ask the sessiond since
-	 * something went wrong in the parsing of data above.
-	 */
-	return ret;
 
-ask_sessiond:
-	ret = lttng_ctl_ask_sessiond(&lsm, NULL);
+	lttng_dynamic_buffer_reset(&buf);
 	return ret;
 }
 
@@ -1397,22 +1378,29 @@ ask_sessiond:
 int lttng_disable_event(struct lttng_handle *handle, const char *name,
 		const char *channel_name)
 {
+	int ret;
 	struct lttng_event ev;
 
 	memset(&ev, 0, sizeof(ev));
 	ev.loglevel = -1;
 	ev.type = LTTNG_EVENT_ALL;
-	lttng_ctl_copy_string(ev.name, name, sizeof(ev.name));
-	return lttng_disable_event_ext(handle, &ev, channel_name, NULL);
+	ret = lttng_strncpy(ev.name, name ?: "", sizeof(ev.name));
+	if (ret) {
+		ret = -LTTNG_ERR_INVALID;
+		goto end;
+	}
+
+	ret = lttng_disable_event_ext(handle, &ev, channel_name, NULL);
+end:
+	return ret;
 }
 
 struct lttng_channel *lttng_channel_create(struct lttng_domain *domain)
 {
 	struct lttng_channel *channel = NULL;
-	struct lttng_channel_extended *extended = NULL;
 
 	if (!domain) {
-		goto error;
+		goto end;
 	}
 
 	/* Validate domain. */
@@ -1423,36 +1411,26 @@ struct lttng_channel *lttng_channel_create(struct lttng_domain *domain)
 		case LTTNG_BUFFER_PER_PID:
 			break;
 		default:
-			goto error;
+			goto end;
 		}
 		break;
 	case LTTNG_DOMAIN_KERNEL:
 		if (domain->buf_type != LTTNG_BUFFER_GLOBAL) {
-			goto error;
+			goto end;
 		}
 		break;
 	default:
-		goto error;
+		goto end;
 	}
 
-	channel = zmalloc(sizeof(*channel));
+	channel = lttng_channel_create_internal();
 	if (!channel) {
-		goto error;
-	}
-
-	extended = zmalloc(sizeof(*extended));
-	if (!extended) {
-		goto error;
+		goto end;
 	}
 
-	channel->attr.extended.ptr = extended;
-
 	lttng_channel_set_default_attr(domain, &channel->attr);
+end:
 	return channel;
-error:
-	free(channel);
-	free(extended);
-	return NULL;
 }
 
 void lttng_channel_destroy(struct lttng_channel *channel)
@@ -1474,49 +1452,89 @@ void lttng_channel_destroy(struct lttng_channel *channel)
 int lttng_enable_channel(struct lttng_handle *handle,
 		struct lttng_channel *in_chan)
 {
+	enum lttng_error_code ret_code;
+	int ret;
+	struct lttng_dynamic_buffer buffer;
 	struct lttcomm_session_msg lsm;
+	uint64_t total_buffer_size_needed_per_cpu = 0;
+	struct lttng_channel *channel = NULL;
+
+	lttng_dynamic_buffer_init(&buffer);
 
 	/* NULL arguments are forbidden. No default values. */
 	if (handle == NULL || in_chan == NULL) {
-		return -LTTNG_ERR_INVALID;
+		ret = -LTTNG_ERR_INVALID;
+		goto end;
 	}
 
-	memset(&lsm, 0, sizeof(lsm));
-	memcpy(&lsm.u.channel.chan, in_chan, sizeof(lsm.u.channel.chan));
-	lsm.u.channel.chan.attr.extended.ptr = NULL;
+	/*
+	 * Verify that the amount of memory required to create the requested
+	 * buffer is available on the system at the moment.
+	 */
+	if (in_chan->attr.num_subbuf >
+			UINT64_MAX / in_chan->attr.subbuf_size) {
+		/* Overflow */
+		ret = -LTTNG_ERR_OVERFLOW;
+		goto end;
+	}
 
-	if (!in_chan->attr.extended.ptr) {
-		struct lttng_channel *channel;
-		struct lttng_channel_extended *extended;
+	total_buffer_size_needed_per_cpu =
+			in_chan->attr.num_subbuf * in_chan->attr.subbuf_size;
+	ret_code = check_enough_available_memory(
+			total_buffer_size_needed_per_cpu);
+	if (ret_code != LTTNG_OK) {
+		ret = -ret_code;
+		goto end;
+	}
 
-		channel = lttng_channel_create(&handle->domain);
-		if (!channel) {
-			return -LTTNG_ERR_NOMEM;
-		}
+	/* Copy the channel for easier manipulation. */
+	channel = lttng_channel_copy(in_chan);
+	if (!channel) {
+		ret = -LTTNG_ERR_NOMEM;
+		goto end;
+	}
 
-		/*
-		 * Create a new channel in order to use default extended
-		 * attribute values.
-		 */
-		extended = (struct lttng_channel_extended *)
-				channel->attr.extended.ptr;
-		memcpy(&lsm.u.channel.extended, extended, sizeof(*extended));
-		lttng_channel_destroy(channel);
-	} else {
-		struct lttng_channel_extended *extended;
+	/* Populate the channel extended attribute if necessary. */
+	if (!channel->attr.extended.ptr) {
+		struct lttng_channel_extended *extended =
+				zmalloc(sizeof(*extended));
 
-		extended = (struct lttng_channel_extended *)
-				in_chan->attr.extended.ptr;
-		memcpy(&lsm.u.channel.extended, extended, sizeof(*extended));
+		if (!extended) {
+			ret = -LTTNG_ERR_NOMEM;
+			goto end;
+		}
+		lttng_channel_set_default_extended_attr(
+				&handle->domain, extended);
+		channel->attr.extended.ptr = extended;
 	}
 
+	/* Prepare the payload */
+	memset(&lsm, 0, sizeof(lsm));
+
 	lsm.cmd_type = LTTNG_ENABLE_CHANNEL;
-	lttng_ctl_copy_lttng_domain(&lsm.domain, &handle->domain);
+	COPY_DOMAIN_PACKED(lsm.domain, handle->domain);
 
-	lttng_ctl_copy_string(lsm.session.name, handle->session_name,
-			sizeof(lsm.session.name));
+	ret = lttng_strncpy(lsm.session.name, handle->session_name,
+				    sizeof(lsm.session.name));
+	if (ret) {
+		ret = -LTTNG_ERR_INVALID;
+		goto end;
+	}
 
-	return lttng_ctl_ask_sessiond(&lsm, NULL);
+	ret = lttng_channel_serialize(channel, &buffer);
+	if (ret) {
+		ret = -LTTNG_ERR_FATAL;
+		goto end;
+	}
+
+	lsm.u.channel.length = buffer.size;
+
+	ret = lttng_ctl_ask_sessiond_varlen_no_cmd_header(
+			&lsm, buffer.data, buffer.size, NULL);
+end:
+	lttng_channel_destroy(channel);
+	lttng_dynamic_buffer_reset(&buffer);
+	return ret;
 }
 
 /*
@@ -1525,6 +1543,7 @@ int lttng_enable_channel(struct lttng_handle *handle,
  */
 int lttng_disable_channel(struct lttng_handle *handle, const char *name)
 {
+	int ret;
 	struct lttcomm_session_msg lsm;
 
 	/* Safety check. Both are mandatory. */
@@ -1536,67 +1555,25 @@ int lttng_disable_channel(struct lttng_handle *handle, const char *name)
 
 	lsm.cmd_type = LTTNG_DISABLE_CHANNEL;
 
-	lttng_ctl_copy_string(lsm.u.disable.channel_name, name,
+	ret = lttng_strncpy(lsm.u.disable.channel_name, name,
 			sizeof(lsm.u.disable.channel_name));
-
-	lttng_ctl_copy_lttng_domain(&lsm.domain, &handle->domain);
-
-	lttng_ctl_copy_string(lsm.session.name, handle->session_name,
-			sizeof(lsm.session.name));
-
-	return lttng_ctl_ask_sessiond(&lsm, NULL);
-}
-
-/*
- * Add PID to session tracker.
- * Return 0 on success else a negative LTTng error code.
- */
-int lttng_track_pid(struct lttng_handle *handle, int pid)
-{
-	struct lttcomm_session_msg lsm;
-
-	/* NULL arguments are forbidden. No default values. */
-	if (handle == NULL) {
-		return -LTTNG_ERR_INVALID;
+	if (ret) {
+		ret = -LTTNG_ERR_INVALID;
+		goto end;
 	}
 
-	memset(&lsm, 0, sizeof(lsm));
-
-	lsm.cmd_type = LTTNG_TRACK_PID;
-	lsm.u.pid_tracker.pid = pid;
-
-	lttng_ctl_copy_lttng_domain(&lsm.domain, &handle->domain);
-
-	lttng_ctl_copy_string(lsm.session.name, handle->session_name,
-			sizeof(lsm.session.name));
-
-	return lttng_ctl_ask_sessiond(&lsm, NULL);
-}
+	COPY_DOMAIN_PACKED(lsm.domain, handle->domain);
 
-/*
- * Remove PID from session tracker.
- * Return 0 on success else a negative LTTng error code.
- */
-int lttng_untrack_pid(struct lttng_handle *handle, int pid)
-{
-	struct lttcomm_session_msg lsm;
-
-	/* NULL arguments are forbidden. No default values. */
-	if (handle == NULL) {
-		return -LTTNG_ERR_INVALID;
+	ret = lttng_strncpy(lsm.session.name, handle->session_name,
+			    sizeof(lsm.session.name));
+	if (ret) {
+		ret = -LTTNG_ERR_INVALID;
+		goto end;
 	}
 
-	memset(&lsm, 0, sizeof(lsm));
-
-	lsm.cmd_type = LTTNG_UNTRACK_PID;
-	lsm.u.pid_tracker.pid = pid;
-
-	lttng_ctl_copy_lttng_domain(&lsm.domain, &handle->domain);
-
-	lttng_ctl_copy_string(lsm.session.name, handle->session_name,
-			sizeof(lsm.session.name));
-
-	return lttng_ctl_ask_sessiond(&lsm, NULL);
+	ret = lttng_ctl_ask_sessiond(&lsm, NULL);
+end:
+	return ret;
 }
 
 /*
@@ -1608,23 +1585,62 @@ int lttng_untrack_pid(struct lttng_handle *handle, int pid)
 int lttng_list_tracepoints(struct lttng_handle *handle,
 		struct lttng_event **events)
 {
-	int ret;
+	enum lttng_error_code ret_code;
+	int ret, total_payload_received;
+	char *reception_buffer = NULL;
 	struct lttcomm_session_msg lsm;
+	struct lttcomm_list_command_header *cmd_header = NULL;
+	size_t cmd_header_len;
+	unsigned int nb_events = 0;
 
 	if (handle == NULL) {
-		return -LTTNG_ERR_INVALID;
+		ret = -LTTNG_ERR_INVALID;
+		goto end;
 	}
 
 	memset(&lsm, 0, sizeof(lsm));
 	lsm.cmd_type = LTTNG_LIST_TRACEPOINTS;
-	lttng_ctl_copy_lttng_domain(&lsm.domain, &handle->domain);
+	COPY_DOMAIN_PACKED(lsm.domain, handle->domain);
 
-	ret = lttng_ctl_ask_sessiond(&lsm, (void **) events);
+	ret = lttng_ctl_ask_sessiond_fds_varlen(&lsm, NULL, 0, NULL, 0,
+			(void **) &reception_buffer, (void **) &cmd_header,
+			&cmd_header_len);
 	if (ret < 0) {
-		return ret;
+		goto end;
 	}
+	total_payload_received = ret;
 
-	return ret / sizeof(struct lttng_event);
+	if (!cmd_header) {
+		ret = -LTTNG_ERR_UNK;
+		goto end;
+	}
+
+	if (cmd_header->count > INT_MAX) {
+		ret = -LTTNG_ERR_OVERFLOW;
+		goto end;
+	}
+
+	nb_events = (unsigned int) cmd_header->count;
+
+	{
+		const struct lttng_buffer_view events_view =
+				lttng_buffer_view_init(reception_buffer, 0,
+						total_payload_received);
+
+		ret_code = lttng_events_create_and_flatten_from_buffer(
+				&events_view, nb_events, events);
+		if (ret_code != LTTNG_OK) {
+			ret = -ret_code;
+			goto end;
+		}
+	}
+
+	ret = (int) nb_events;
+
+end:
+	free(cmd_header);
+	free(reception_buffer);
+	return ret;
 }
 
 /*
@@ -1636,8 +1652,13 @@ int lttng_list_tracepoints(struct lttng_handle *handle,
 int lttng_list_tracepoint_fields(struct lttng_handle *handle,
 		struct lttng_event_field **fields)
 {
-	int ret;
+	enum lttng_error_code ret_code;
+	int ret, total_payload_received;
 	struct lttcomm_session_msg lsm;
+	char *reception_buffer = NULL;
+	struct lttcomm_list_command_header *cmd_header = NULL;
+	size_t cmd_header_len;
+	unsigned int nb_event_fields = 0;
 
 	if (handle == NULL) {
 		return -LTTNG_ERR_INVALID;
@@ -1645,14 +1666,47 @@ int lttng_list_tracepoint_fields(struct lttng_handle *handle,
 
 	memset(&lsm, 0, sizeof(lsm));
 	lsm.cmd_type = LTTNG_LIST_TRACEPOINT_FIELDS;
-	lttng_ctl_copy_lttng_domain(&lsm.domain, &handle->domain);
+	COPY_DOMAIN_PACKED(lsm.domain, handle->domain);
 
-	ret = lttng_ctl_ask_sessiond(&lsm, (void **) fields);
+	ret = lttng_ctl_ask_sessiond_fds_varlen(&lsm, NULL, 0, NULL, 0,
+			(void **) &reception_buffer, (void **) &cmd_header,
+			&cmd_header_len);
 	if (ret < 0) {
-		return ret;
+		goto end;
 	}
 
-	return ret / sizeof(struct lttng_event_field);
+	total_payload_received = ret;
+
+	if (!cmd_header) {
+		ret = -LTTNG_ERR_UNK;
+		goto end;
+	}
+
+	if (cmd_header->count > INT_MAX) {
+		ret = -LTTNG_ERR_OVERFLOW;
+		goto end;
+	}
+
+	nb_event_fields = cmd_header->count;
+
+	{
+		const struct lttng_buffer_view view =
+			lttng_buffer_view_init(reception_buffer, 0, total_payload_received);
+
+		ret_code = lttng_event_fields_create_and_flatten_from_buffer(
+				&view, nb_event_fields, fields);
+		if (ret_code != LTTNG_OK) {
+			ret = -ret_code;
+			goto end;
+		}
+	}
+
+	ret = nb_event_fields;
+
+end:
+	free(cmd_header);
+	free(reception_buffer);
+	return ret;
 }
 
 /*
@@ -1664,11 +1718,17 @@ int lttng_list_tracepoint_fields(struct lttng_handle *handle,
  */
 int lttng_list_syscalls(struct lttng_event **events)
 {
-	int ret;
+	enum lttng_error_code ret_code;
+	int ret, total_payload_received;
+	char *reception_buffer = NULL;
 	struct lttcomm_session_msg lsm;
+	struct lttcomm_list_command_header *cmd_header = NULL;
+	size_t cmd_header_len;
+	uint32_t nb_events = 0;
 
 	if (!events) {
-		return -LTTNG_ERR_INVALID;
+		ret = -LTTNG_ERR_INVALID;
+		goto end;
 	}
 
 	memset(&lsm, 0, sizeof(lsm));
@@ -1676,12 +1736,45 @@ int lttng_list_syscalls(struct lttng_event **events)
 	/* Force kernel domain for system calls. */
 	lsm.domain.type = LTTNG_DOMAIN_KERNEL;
 
-	ret = lttng_ctl_ask_sessiond(&lsm, (void **) events);
+	ret = lttng_ctl_ask_sessiond_fds_varlen(&lsm, NULL, 0, NULL, 0,
+			(void **) &reception_buffer, (void **) &cmd_header,
+			&cmd_header_len);
 	if (ret < 0) {
-		return ret;
+		goto end;
+	}
+	total_payload_received = ret;
+
+	if (!cmd_header) {
+		ret = -LTTNG_ERR_UNK;
+		goto end;
+	}
+
+	if (cmd_header->count > INT_MAX) {
+		ret = -LTTNG_ERR_OVERFLOW;
+		goto end;
+	}
+
+	nb_events = (unsigned int) cmd_header->count;
+
+	{
+		const struct lttng_buffer_view events_view =
+				lttng_buffer_view_init(reception_buffer, 0,
+						total_payload_received);
+
+		ret_code = lttng_events_create_and_flatten_from_buffer(
+				&events_view, nb_events, events);
+		if (ret_code != LTTNG_OK) {
+			ret = -ret_code;
+			goto end;
+		}
 	}
 
-	return ret / sizeof(struct lttng_event);
+	ret = (int) nb_events;
+
+end:
+	free(reception_buffer);
+	free(cmd_header);
+	return ret;
 }
 
 /*
@@ -1693,81 +1786,296 @@ const char *lttng_strerror(int code)
 	return error_get_str(code);
 }
 
+enum lttng_error_code lttng_create_session_ext(
+		struct lttng_session_descriptor *session_descriptor)
+{
+	enum lttng_error_code ret_code;
+	struct lttcomm_session_msg lsm = {
+		.cmd_type = LTTNG_CREATE_SESSION_EXT,
+	};
+	void *reply = NULL;
+	struct lttng_buffer_view reply_view;
+	int reply_ret;
+	bool sessiond_must_generate_ouput;
+	struct lttng_dynamic_buffer payload;
+	int ret;
+	size_t descriptor_size;
+	struct lttng_session_descriptor *descriptor_reply = NULL;
+
+	lttng_dynamic_buffer_init(&payload);
+	if (!session_descriptor) {
+		ret_code = LTTNG_ERR_INVALID;
+		goto end;
+	}
+
+	sessiond_must_generate_ouput =
+			!lttng_session_descriptor_is_output_destination_initialized(
+				session_descriptor);
+	if (sessiond_must_generate_ouput) {
+		const char *home_dir = utils_get_home_dir();
+		size_t home_dir_len = home_dir ? strlen(home_dir) + 1 : 0;
+
+		if (!home_dir || home_dir_len > LTTNG_PATH_MAX) {
+			ret_code = LTTNG_ERR_FATAL;
+			goto end;
+		}
+
+		lsm.u.create_session.home_dir_size = (uint16_t) home_dir_len;
+		ret = lttng_dynamic_buffer_append(&payload, home_dir,
+				home_dir_len);
+		if (ret) {
+			ret_code = LTTNG_ERR_NOMEM;
+			goto end;
+		}
+	}
+
+	descriptor_size = payload.size;
+	ret = lttng_session_descriptor_serialize(session_descriptor,
+			&payload);
+	if (ret) {
+		ret_code = LTTNG_ERR_INVALID;
+		goto end;
+	}
+	descriptor_size = payload.size - descriptor_size;
+	lsm.u.create_session.session_descriptor_size = descriptor_size;
+
+	/* Command returns a session descriptor on success. */
+	reply_ret = lttng_ctl_ask_sessiond_varlen_no_cmd_header(&lsm, payload.data,
+			payload.size, &reply);
+	if (reply_ret < 0) {
+		ret_code = -reply_ret;
+		goto end;
+	} else if (reply_ret == 0) {
+		/* Socket unexpectedly closed by the session daemon. */
+		ret_code = LTTNG_ERR_FATAL;
+		goto end;
+	}
+
+	reply_view = lttng_buffer_view_init(reply, 0, reply_ret);
+	ret = lttng_session_descriptor_create_from_buffer(&reply_view,
+			&descriptor_reply);
+	if (ret < 0) {
+		ret_code = LTTNG_ERR_FATAL;
+		goto end;
+	}
+	ret_code = LTTNG_OK;
+	lttng_session_descriptor_assign(session_descriptor, descriptor_reply);
+end:
+	free(reply);
+	lttng_dynamic_buffer_reset(&payload);
+	lttng_session_descriptor_destroy(descriptor_reply);
+	return ret_code;
+}
+
 /*
- * Create a brand new session using name and url for destination.
+ * Create a new session using name and url for destination.
  *
- * Returns LTTNG_OK on success or a negative error code.
+ * Return 0 on success else a negative LTTng error code.
  */
 int lttng_create_session(const char *name, const char *url)
 {
 	int ret;
 	ssize_t size;
-	struct lttcomm_session_msg lsm;
 	struct lttng_uri *uris = NULL;
+	struct lttng_session_descriptor *descriptor = NULL;
+	enum lttng_error_code ret_code;
 
-	if (name == NULL) {
-		return -LTTNG_ERR_INVALID;
+	if (!name) {
+		ret = -LTTNG_ERR_INVALID;
+		goto end;
 	}
 
-	memset(&lsm, 0, sizeof(lsm));
-
-	lsm.cmd_type = LTTNG_CREATE_SESSION;
-	lttng_ctl_copy_string(lsm.session.name, name, sizeof(lsm.session.name));
-
-	/* There should never be a data URL */
 	size = uri_parse_str_urls(url, NULL, &uris);
 	if (size < 0) {
-		return -LTTNG_ERR_INVALID;
+		ret = -LTTNG_ERR_INVALID;
+		goto end;
 	}
+	switch (size) {
+	case 0:
+		descriptor = lttng_session_descriptor_create(name);
+		break;
+	case 1:
+		if (uris[0].dtype != LTTNG_DST_PATH) {
+			ret = -LTTNG_ERR_INVALID;
+			goto end;
+		}
+		descriptor = lttng_session_descriptor_local_create(name,
+				uris[0].dst.path);
+		break;
+	case 2:
+		descriptor = lttng_session_descriptor_network_create(name, url,
+				NULL);
+		break;
+	default:
+		ret = -LTTNG_ERR_INVALID;
+		goto end;
+	}
+	if (!descriptor) {
+		ret = -LTTNG_ERR_INVALID;
+		goto end;
+	}
+	ret_code = lttng_create_session_ext(descriptor);
+	ret = ret_code == LTTNG_OK ? 0 : -ret_code;
+end:
+	lttng_session_descriptor_destroy(descriptor);
+	free(uris);
+	return ret;
+}
 
-	lsm.u.uri.size = size;
+/*
+ * Create a session exclusively used for snapshot.
+ *
+ * Return 0 on success else a negative LTTng error code.
+ */
+int lttng_create_session_snapshot(const char *name, const char *snapshot_url)
+{
+	int ret;
+	enum lttng_error_code ret_code;
+	ssize_t size;
+	struct lttng_uri *uris = NULL;
+	struct lttng_session_descriptor *descriptor = NULL;
 
-	ret = lttng_ctl_ask_sessiond_varlen_no_cmd_header(&lsm, uris,
-			sizeof(struct lttng_uri) * size, NULL);
+	if (!name) {
+		ret = -LTTNG_ERR_INVALID;
+		goto end;
+	}
+
+	size = uri_parse_str_urls(snapshot_url, NULL, &uris);
+	if (size < 0) {
+		ret = -LTTNG_ERR_INVALID;
+		goto end;
+	}
+	/*
+	 * If the user does not specify a custom subdir, use the session name.
+	 */
+	if (size > 0 && uris[0].dtype != LTTNG_DST_PATH &&
+			strlen(uris[0].subdir) == 0) {
+		ret = snprintf(uris[0].subdir, sizeof(uris[0].subdir), "%s",
+				name);
+		if (ret < 0) {
+			PERROR("Failed to set session name as network destination sub-directory");
+			ret = -LTTNG_ERR_FATAL;
+			goto end;
+		} else if (ret >= sizeof(uris[0].subdir)) {
+			/* Truncated output. */
+			ret = -LTTNG_ERR_INVALID;
+			goto end;
+		}
+	}
 
+	switch (size) {
+	case 0:
+		descriptor = lttng_session_descriptor_snapshot_create(name);
+		break;
+	case 1:
+		if (uris[0].dtype != LTTNG_DST_PATH) {
+			ret = -LTTNG_ERR_INVALID;
+			goto end;
+		}
+		descriptor = lttng_session_descriptor_snapshot_local_create(
+				name,
+				uris[0].dst.path);
+		break;
+	case 2:
+		descriptor = lttng_session_descriptor_snapshot_network_create(
+				name,
+				snapshot_url,
+				NULL);
+		break;
+	default:
+		ret = -LTTNG_ERR_INVALID;
+		goto end;
+	}
+	if (!descriptor) {
+		ret = -LTTNG_ERR_INVALID;
+		goto end;
+	}
+	ret_code = lttng_create_session_ext(descriptor);
+	ret = ret_code == LTTNG_OK ? 0 : -ret_code;
+end:
+	lttng_session_descriptor_destroy(descriptor);
 	free(uris);
 	return ret;
 }
 
 /*
- * Destroy session using name.
- * Returns size of returned session payload data or a negative error code.
+ * Create a session exclusively used for live.
+ *
+ * Return 0 on success else a negative LTTng error code.
  */
-static
-int _lttng_destroy_session(const char *session_name)
+int lttng_create_session_live(const char *name, const char *url,
+		unsigned int timer_interval)
 {
-	struct lttcomm_session_msg lsm;
+	int ret;
+	enum lttng_error_code ret_code;
+	struct lttng_session_descriptor *descriptor = NULL;
 
-	if (session_name == NULL) {
-		return -LTTNG_ERR_INVALID;
+	if (!name) {
+		ret = -LTTNG_ERR_INVALID;
+		goto end;
 	}
 
-	memset(&lsm, 0, sizeof(lsm));
-	lsm.cmd_type = LTTNG_DESTROY_SESSION;
-
-	lttng_ctl_copy_string(lsm.session.name, session_name,
-			sizeof(lsm.session.name));
-
-	return lttng_ctl_ask_sessiond(&lsm, NULL);
+	if (url) {
+		descriptor = lttng_session_descriptor_live_network_create(
+				name, url, NULL, timer_interval);
+	} else {
+		descriptor = lttng_session_descriptor_live_create(
+				name, timer_interval);
+	}
+	if (!descriptor) {
+		ret = -LTTNG_ERR_INVALID;
+		goto end;
+	}
+	ret_code = lttng_create_session_ext(descriptor);
+	ret = ret_code == LTTNG_OK ? 0 : -ret_code;
+end:
+	lttng_session_descriptor_destroy(descriptor);
+	return ret;
 }
 
 /*
  * Stop the session and wait for the data before destroying it
+ *
+ * Return 0 on success else a negative LTTng error code.
  */
 int lttng_destroy_session(const char *session_name)
 {
 	int ret;
+	enum lttng_error_code ret_code;
+	enum lttng_destruction_handle_status status;
+	struct lttng_destruction_handle *handle = NULL;
 
 	/*
-	 * Stop the tracing and wait for the data.
+	 * Stop the tracing and wait for the data to be
+	 * consumed.
 	 */
 	ret = _lttng_stop_tracing(session_name, 1);
 	if (ret && ret != -LTTNG_ERR_TRACE_ALREADY_STOPPED) {
 		goto end;
 	}
 
-	ret = _lttng_destroy_session(session_name);
+	ret_code = lttng_destroy_session_ext(session_name, &handle);
+	if (ret_code != LTTNG_OK) {
+		ret = (int) -ret_code;
+		goto end;
+	}
+	assert(handle);
+
+	/* Block until the completion of the destruction of the session. */
+	status = lttng_destruction_handle_wait_for_completion(handle, -1);
+	if (status != LTTNG_DESTRUCTION_HANDLE_STATUS_COMPLETED) {
+		ret = -LTTNG_ERR_UNK;
+		goto end;
+	}
+
+	status = lttng_destruction_handle_get_result(handle, &ret_code);
+	if (status != LTTNG_DESTRUCTION_HANDLE_STATUS_OK) {
+		ret = -LTTNG_ERR_UNK;
+		goto end;
+	}
+	ret = ret_code == LTTNG_OK ? 0 : -ret_code;
 end:
+	lttng_destruction_handle_destroy(handle);
 	return ret;
 }
 
@@ -1776,21 +2084,10 @@ end:
  */
 int lttng_destroy_session_no_wait(const char *session_name)
 {
-	int ret;
-
-	/*
-	 * Stop the tracing without waiting for the data.
-	 * The session might already have been stopped, so just
-	 * skip this error.
-	 */
-	ret = _lttng_stop_tracing(session_name, 0);
-	if (ret && ret != -LTTNG_ERR_TRACE_ALREADY_STOPPED) {
-		goto end;
-	}
+	enum lttng_error_code ret_code;
 
-	ret = _lttng_destroy_session(session_name);
-end:
-	return ret;
+	ret_code = lttng_destroy_session_ext(session_name, NULL);
+	return ret_code == LTTNG_OK ? 0 : -ret_code;
 }
 
 /*
@@ -1799,24 +2096,83 @@ end:
  * Returns the number of lttng_session entries in sessions;
  * on error, returns a negative value.
  */
-int lttng_list_sessions(struct lttng_session **sessions)
+int lttng_list_sessions(struct lttng_session **out_sessions)
 {
 	int ret;
 	struct lttcomm_session_msg lsm;
+	const size_t session_size = sizeof(struct lttng_session) +
+			sizeof(struct lttng_session_extended);
+	size_t session_count, i;
+	struct lttng_session_extended *sessions_extended_begin;
+	struct lttng_session *sessions = NULL;
 
 	memset(&lsm, 0, sizeof(lsm));
 	lsm.cmd_type = LTTNG_LIST_SESSIONS;
-	ret = lttng_ctl_ask_sessiond(&lsm, (void**) sessions);
-	if (ret < 0) {
-		return ret;
+	/*
+	 * Initialize out_sessions to NULL so it is initialized when
+	 * lttng_list_sessions returns 0, thus allowing *out_sessions to
+	 * be subsequently freed.
+	 */
+	*out_sessions = NULL;
+	ret = lttng_ctl_ask_sessiond(&lsm, (void**) &sessions);
+	if (ret <= 0) {
+		goto end;
+	}
+	if (!sessions) {
+		ret = -LTTNG_ERR_FATAL;
+		goto end;
 	}
 
-	return ret / sizeof(struct lttng_session);
+	if (ret % session_size) {
+		ret = -LTTNG_ERR_UNK;
+		free(sessions);
+		goto end;
+	}
+	session_count = (size_t) ret / session_size;
+	sessions_extended_begin = (struct lttng_session_extended *)
+			(&sessions[session_count]);
+
+	/* Set extended session info pointers. */
+	for (i = 0; i < session_count; i++) {
+		struct lttng_session *session = &sessions[i];
+		struct lttng_session_extended *extended =
+				&(sessions_extended_begin[i]);
+
+		session->extended.ptr = extended;
+	}
+
+	ret = (int) session_count;
+	*out_sessions = sessions;
+end:
+	return ret;
+}
+
+enum lttng_error_code lttng_session_get_creation_time(
+		const struct lttng_session *session, uint64_t *creation_time)
+{
+	enum lttng_error_code ret = LTTNG_OK;
+	struct lttng_session_extended *extended;
+
+	if (!session || !creation_time || !session->extended.ptr) {
+		ret = LTTNG_ERR_INVALID;
+		goto end;
+	}
+
+	extended = session->extended.ptr;
+	if (!extended->creation_time.is_set) {
+		/* Not created on the session daemon yet. */
+		ret = LTTNG_ERR_SESSION_NOT_EXIST;
+		goto end;
+	}
+	*creation_time = extended->creation_time.value;
+end:
+	return ret;
 }
 
 int lttng_set_session_shm_path(const char *session_name,
 		const char *shm_path)
 {
+	int ret;
 	struct lttcomm_session_msg lsm;
 
 	if (session_name == NULL) {
@@ -1826,12 +2182,23 @@ int lttng_set_session_shm_path(const char *session_name,
 	memset(&lsm, 0, sizeof(lsm));
 	lsm.cmd_type = LTTNG_SET_SESSION_SHM_PATH;
 
-	lttng_ctl_copy_string(lsm.session.name, session_name,
+	ret = lttng_strncpy(lsm.session.name, session_name,
 			sizeof(lsm.session.name));
-	lttng_ctl_copy_string(lsm.u.set_shm_path.shm_path, shm_path,
+	if (ret) {
+		ret = -LTTNG_ERR_INVALID;
+		goto end;
+	}
+
+	ret = lttng_strncpy(lsm.u.set_shm_path.shm_path, shm_path ?: "",
 			sizeof(lsm.u.set_shm_path.shm_path));
+	if (ret) {
+		ret = -LTTNG_ERR_INVALID;
+		goto end;
+	}
 
-	return lttng_ctl_ask_sessiond(&lsm, NULL);
+	ret = lttng_ctl_ask_sessiond(&lsm, NULL);
+end:
+	return ret;
 }
 
 /*
@@ -1847,21 +2214,28 @@ int lttng_list_domains(const char *session_name,
 	struct lttcomm_session_msg lsm;
 
 	if (session_name == NULL) {
-		return -LTTNG_ERR_INVALID;
+		ret = -LTTNG_ERR_INVALID;
+		goto error;
 	}
 
 	memset(&lsm, 0, sizeof(lsm));
 	lsm.cmd_type = LTTNG_LIST_DOMAINS;
 
-	lttng_ctl_copy_string(lsm.session.name, session_name,
+	ret = lttng_strncpy(lsm.session.name, session_name,
 			sizeof(lsm.session.name));
+	if (ret) {
+		ret = -LTTNG_ERR_INVALID;
+		goto error;
+	}
 
 	ret = lttng_ctl_ask_sessiond(&lsm, (void**) domains);
 	if (ret < 0) {
-		return ret;
+		goto error;
 	}
 
 	return ret / sizeof(struct lttng_domain);
+error:
+	return ret;
 }
 
 /*
@@ -1873,12 +2247,14 @@ int lttng_list_domains(const char *session_name,
 int lttng_list_channels(struct lttng_handle *handle,
 		struct lttng_channel **channels)
 {
-	int ret;
-	size_t channel_count, i;
-	const size_t channel_size = sizeof(struct lttng_channel) +
-			sizeof(struct lttng_channel_extended);
+	int ret, total_payload_received;
 	struct lttcomm_session_msg lsm;
-	void *extended_at;
+	char *reception_buffer = NULL;
+	size_t cmd_header_len = 0;
+	struct lttcomm_list_command_header *cmd_header = NULL;
+	struct lttng_dynamic_buffer tmp_buffer;
+
+	lttng_dynamic_buffer_init(&tmp_buffer);
 
 	if (handle == NULL) {
 		ret = -LTTNG_ERR_INVALID;
@@ -1887,36 +2263,57 @@ int lttng_list_channels(struct lttng_handle *handle,
 
 	memset(&lsm, 0, sizeof(lsm));
 	lsm.cmd_type = LTTNG_LIST_CHANNELS;
-	lttng_ctl_copy_string(lsm.session.name, handle->session_name,
+	ret = lttng_strncpy(lsm.session.name, handle->session_name,
 			sizeof(lsm.session.name));
+	if (ret) {
+		ret = -LTTNG_ERR_INVALID;
+		goto end;
+	}
 
-	lttng_ctl_copy_lttng_domain(&lsm.domain, &handle->domain);
+	COPY_DOMAIN_PACKED(lsm.domain, handle->domain);
 
-	ret = lttng_ctl_ask_sessiond(&lsm, (void**) channels);
+	ret = lttng_ctl_ask_sessiond_fds_varlen(&lsm, NULL, 0, NULL, 0,
+			(void **) &reception_buffer, (void **) &cmd_header,
+			&cmd_header_len);
 	if (ret < 0) {
 		goto end;
 	}
 
-	if (ret % channel_size) {
-		ret = -LTTNG_ERR_UNK;
-		free(*channels);
-		*channels = NULL;
+	total_payload_received = ret;
+
+	if (cmd_header_len != sizeof(*cmd_header)) {
+		ret = -LTTNG_ERR_FATAL;
+		goto end;
+	}
+
+	if (!cmd_header) {
+		ret = LTTNG_ERR_UNK;
+		goto end;
+	}
+
+	if (cmd_header->count > INT_MAX) {
+		ret = -LTTNG_ERR_OVERFLOW;
 		goto end;
 	}
-	channel_count = (size_t) ret / channel_size;
 
-	/* Set extended info pointers */
-	extended_at = ((void *) *channels) +
-			channel_count * sizeof(struct lttng_channel);
-	for (i = 0; i < channel_count; i++) {
-		struct lttng_channel *chan = &(*channels)[i];
+	{
+		enum lttng_error_code ret_code;
+		const struct lttng_buffer_view events_view =
+				lttng_buffer_view_init(reception_buffer, 0,
+						total_payload_received);
 
-		chan->attr.extended.ptr = extended_at;
-		extended_at += sizeof(struct lttng_channel_extended);
+		ret_code = lttng_channels_create_and_flatten_from_buffer(
+				&events_view, cmd_header->count, channels);
+		if (ret_code != LTTNG_OK) {
+			ret = -ret_code;
+			goto end;
+		}
 	}
 
-	ret = (int) channel_count;
+	ret = (int) cmd_header->count;
 end:
+	free(cmd_header);
+	free(reception_buffer);
 	return ret;
 }
 
@@ -1929,15 +2326,17 @@ end:
 int lttng_list_events(struct lttng_handle *handle,
 		const char *channel_name, struct lttng_event **events)
 {
+	enum lttng_error_code ret_code;
 	int ret;
 	struct lttcomm_session_msg lsm;
-	struct lttcomm_event_command_header *cmd_header = NULL;
+	struct lttcomm_list_command_header *cmd_header = NULL;
 	size_t cmd_header_len;
-	uint32_t nb_events, i;
-	void *comm_ext_at;
+	unsigned int nb_events;
 	char *reception_buffer = NULL;
-	struct lttng_dynamic_buffer listing;
-	size_t storage_req;
+	struct lttng_dynamic_buffer tmp_buffer;
+	ssize_t total_payload_received;
+
+	lttng_dynamic_buffer_init(&tmp_buffer);
 
 	/* Safety check. An handle and channel name are mandatory */
 	if (handle == NULL || channel_name == NULL) {
@@ -1946,11 +2345,21 @@ int lttng_list_events(struct lttng_handle *handle,
 
 	memset(&lsm, 0, sizeof(lsm));
 	lsm.cmd_type = LTTNG_LIST_EVENTS;
-	lttng_ctl_copy_string(lsm.session.name, handle->session_name,
+	ret = lttng_strncpy(lsm.session.name, handle->session_name,
 			sizeof(lsm.session.name));
-	lttng_ctl_copy_string(lsm.u.list.channel_name, channel_name,
+	if (ret) {
+		ret = -LTTNG_ERR_INVALID;
+		goto end;
+	}
+
+	ret = lttng_strncpy(lsm.u.list.channel_name, channel_name,
 			sizeof(lsm.u.list.channel_name));
-	lttng_ctl_copy_lttng_domain(&lsm.domain, &handle->domain);
+	if (ret) {
+		ret = -LTTNG_ERR_INVALID;
+		goto end;
+	}
+
+	COPY_DOMAIN_PACKED(lsm.domain, handle->domain);
 
 	ret = lttng_ctl_ask_sessiond_fds_varlen(&lsm, NULL, 0, NULL, 0,
 		(void **) &reception_buffer, (void **) &cmd_header,
@@ -1959,210 +2368,33 @@ int lttng_list_events(struct lttng_handle *handle,
 		goto end;
 	}
 
+	total_payload_received = ret;
+
 	if (!cmd_header) {
 		ret = -LTTNG_ERR_UNK;
 		goto end;
 	}
 
-	/* Set number of events and free command header */
-	nb_events = cmd_header->nb_events;
-	if (nb_events > INT_MAX) {
-		ret = -EOVERFLOW;
-		goto end;
-	}
-	free(cmd_header);
-	cmd_header = NULL;
-
-	/*
-	 * The buffer that is returned must contain a "flat" version of
-	 * the events that are returned. In other words, all pointers
-	 * within an lttng_event must point to a location within the returned
-	 * buffer so that the user may free everything by simply calling free()
-	 * on the returned buffer. This is needed in order to maintain API
-	 * compatibility.
-	 *
-	 * A first pass is performed to compute the size of the buffer that
-	 * must be allocated. A second pass is then performed to setup
-	 * the returned events so that their members always point within the
-	 * buffer.
-	 *
-	 * The layout of the returned buffer is as follows:
-	 *   - struct lttng_event[nb_events],
-	 *   - nb_events times the following:
-	 *     - struct lttng_event_extended,
-	 *     - flattened version of userspace_probe_location
-	 *     - filter_expression
-	 *     - exclusions
-	 *     - padding to align to 64-bits
-	 */
-	comm_ext_at = reception_buffer +
-		(nb_events * sizeof(struct lttng_event));
-	storage_req = nb_events * sizeof(struct lttng_event);
-
-	for (i = 0; i < nb_events; i++) {
-		struct lttcomm_event_extended_header *ext_comm =
-			(struct lttcomm_event_extended_header *) comm_ext_at;
-		int probe_storage_req = 0;
-
-		comm_ext_at += sizeof(*ext_comm);
-		comm_ext_at += ext_comm->filter_len;
-		comm_ext_at +=
-			ext_comm->nb_exclusions * LTTNG_SYMBOL_NAME_LEN;
-
-		if (ext_comm->userspace_probe_location_len) {
-			struct lttng_userspace_probe_location *probe_location = NULL;
-			struct lttng_buffer_view probe_location_view;
-
-			probe_location_view = lttng_buffer_view_init(
-					comm_ext_at, 0,
-					ext_comm->userspace_probe_location_len);
-
-			/*
-			 * Create a temporary userspace probe location to
-			 * determine the size needed by a "flattened" version
-			 * of that same probe location.
-			 */
-			ret = lttng_userspace_probe_location_create_from_buffer(
-					&probe_location_view, &probe_location);
-			if (ret < 0) {
-				ret = -LTTNG_ERR_PROBE_LOCATION_INVAL;
-				goto end;
-			}
-
-			ret = lttng_userspace_probe_location_flatten(
-					probe_location, NULL);
-			lttng_userspace_probe_location_destroy(probe_location);
-			if (ret < 0) {
-				ret = -LTTNG_ERR_PROBE_LOCATION_INVAL;
-				goto end;
-			}
-
-			probe_storage_req = ret;
-			comm_ext_at += ext_comm->userspace_probe_location_len;
-		}
-
-		storage_req += sizeof(struct lttng_event_extended);
-		storage_req += ext_comm->filter_len;
-		storage_req += ext_comm->nb_exclusions * LTTNG_SYMBOL_NAME_LEN;
-		/* Padding to ensure the flat probe is aligned. */
-		storage_req = ALIGN_TO(storage_req, sizeof(uint64_t));
-		storage_req += probe_storage_req;
-	}
-
-	lttng_dynamic_buffer_init(&listing);
-	/*
-	 * We must ensure that "listing" is never resized so as to preserve
-	 * the validity of the flattened objects.
-	 */
-	ret = lttng_dynamic_buffer_set_capacity(&listing, storage_req);
-	if (ret) {
-		ret = -LTTNG_ERR_NOMEM;
+	if (cmd_header->count > INT_MAX) {
+		ret = -LTTNG_ERR_OVERFLOW;
 		goto end;
 	}
 
-	ret = lttng_dynamic_buffer_append(&listing, reception_buffer,
-			nb_events * sizeof(struct lttng_event));
-	if (ret) {
-		ret = -LTTNG_ERR_NOMEM;
-		goto free_dynamic_buffer;
-	}
-
-	comm_ext_at = reception_buffer +
-			(nb_events * sizeof(struct lttng_event));
-	for (i = 0; i < nb_events; i++) {
-		struct lttng_event *event = (struct lttng_event *)
-			(listing.data + (sizeof(struct lttng_event) * i));
-		struct lttcomm_event_extended_header *ext_comm =
-			(struct lttcomm_event_extended_header *) comm_ext_at;
-		struct lttng_event_extended *event_extended =
-			(struct lttng_event_extended *)
-				(listing.data + listing.size);
-
-		/* Insert struct lttng_event_extended. */
-		ret = lttng_dynamic_buffer_set_size(&listing,
-				listing.size + sizeof(*event_extended));
-		if (ret) {
-			ret = -LTTNG_ERR_NOMEM;
-			goto free_dynamic_buffer;
-		}
-		event->extended.ptr = event_extended;
-
-		comm_ext_at += sizeof(*ext_comm);
-
-		/* Insert filter expression. */
-		if (ext_comm->filter_len) {
-			event_extended->filter_expression = listing.data +
-					listing.size;
-			ret = lttng_dynamic_buffer_append(&listing, comm_ext_at,
-					ext_comm->filter_len);
-			if (ret) {
-				ret = -LTTNG_ERR_NOMEM;
-				goto free_dynamic_buffer;
-			}
-			comm_ext_at += ext_comm->filter_len;
-		}
-
-		/* Insert exclusions. */
-		if (ext_comm->nb_exclusions) {
-			event_extended->exclusions.count =
-					ext_comm->nb_exclusions;
-			event_extended->exclusions.strings =
-					listing.data + listing.size;
-
-			ret = lttng_dynamic_buffer_append(&listing,
-					comm_ext_at,
-					ext_comm->nb_exclusions * LTTNG_SYMBOL_NAME_LEN);
-			if (ret) {
-				ret = -LTTNG_ERR_NOMEM;
-				goto free_dynamic_buffer;
-			}
-			comm_ext_at += ext_comm->nb_exclusions * LTTNG_SYMBOL_NAME_LEN;
-		}
-
-		/* Insert padding to align to 64-bits. */
-		ret = lttng_dynamic_buffer_set_size(&listing,
-				ALIGN_TO(listing.size, sizeof(uint64_t)));
-		if (ret) {
-			ret = -LTTNG_ERR_NOMEM;
-			goto free_dynamic_buffer;
-		}
-
-		/* Insert flattened userspace probe location. */
-		if (ext_comm->userspace_probe_location_len) {
-			struct lttng_userspace_probe_location *probe_location = NULL;
-			struct lttng_buffer_view probe_location_view;
-
-			probe_location_view = lttng_buffer_view_init(
-					comm_ext_at, 0,
-					ext_comm->userspace_probe_location_len);
-
-			ret = lttng_userspace_probe_location_create_from_buffer(
-					&probe_location_view, &probe_location);
-			if (ret < 0) {
-				ret = -LTTNG_ERR_PROBE_LOCATION_INVAL;
-				goto free_dynamic_buffer;
-			}
-
-			event_extended->probe_location = (struct lttng_userspace_probe_location *)
-					(listing.data + listing.size);
-			ret = lttng_userspace_probe_location_flatten(
-					probe_location, &listing);
-			lttng_userspace_probe_location_destroy(probe_location);
-			if (ret < 0) {
-				ret = -LTTNG_ERR_PROBE_LOCATION_INVAL;
-				goto free_dynamic_buffer;
-			}
+	nb_events = (unsigned int) cmd_header->count;
 
-			comm_ext_at += ext_comm->userspace_probe_location_len;
+	{
+		const struct lttng_buffer_view events_view =
+				lttng_buffer_view_init(reception_buffer, 0,
+						total_payload_received);
+		ret_code = lttng_events_create_and_flatten_from_buffer(
+				&events_view, nb_events, events);
+		if (ret_code != LTTNG_OK) {
+			ret = -ret_code;
+			goto end;
 		}
 	}
 
-	/* Don't reset listing buffer as we return its content. */
-	*events = (struct lttng_event *) listing.data;
-	lttng_dynamic_buffer_init(&listing);
 	ret = (int) nb_events;
-free_dynamic_buffer:
-	lttng_dynamic_buffer_reset(&listing);
 end:
 	free(cmd_header);
 	free(reception_buffer);
@@ -2176,14 +2408,19 @@ end:
  */
 int lttng_set_tracing_group(const char *name)
 {
+	char *new_group;
 	if (name == NULL) {
 		return -LTTNG_ERR_INVALID;
 	}
 
-	if (asprintf(&tracing_group, "%s", name) < 0) {
+	if (asprintf(&new_group, "%s", name) < 0) {
 		return -LTTNG_ERR_FATAL;
 	}
 
+	free(tracing_group);
+	tracing_group = new_group;
+	new_group = NULL;
+
 	return 0;
 }
 
@@ -2210,6 +2447,7 @@ void lttng_channel_set_default_attr(struct lttng_domain *domain,
 		return;
 	}
 
+	/* Save the pointer for later use */
 	extended = (struct lttng_channel_extended *) attr->extended.ptr;
 	memset(attr, 0, sizeof(struct lttng_channel_attr));
 
@@ -2226,12 +2464,6 @@ void lttng_channel_set_default_attr(struct lttng_domain *domain,
 		attr->subbuf_size = default_get_kernel_channel_subbuf_size();
 		attr->num_subbuf = DEFAULT_KERNEL_CHANNEL_SUBBUF_NUM;
 		attr->output = DEFAULT_KERNEL_CHANNEL_OUTPUT;
-		if (extended) {
-			extended->monitor_timer_interval =
-					DEFAULT_KERNEL_CHANNEL_MONITOR_TIMER;
-			extended->blocking_timeout =
-					DEFAULT_KERNEL_CHANNEL_BLOCKING_TIMEOUT;
-		}
 		break;
 	case LTTNG_DOMAIN_UST:
 		switch (domain->buf_type) {
@@ -2243,12 +2475,6 @@ void lttng_channel_set_default_attr(struct lttng_domain *domain,
 					DEFAULT_UST_UID_CHANNEL_SWITCH_TIMER;
 			attr->read_timer_interval =
 					DEFAULT_UST_UID_CHANNEL_READ_TIMER;
-			if (extended) {
-				extended->monitor_timer_interval =
-						DEFAULT_UST_UID_CHANNEL_MONITOR_TIMER;
-				extended->blocking_timeout =
-						DEFAULT_UST_UID_CHANNEL_BLOCKING_TIMEOUT;
-			}
 			break;
 		case LTTNG_BUFFER_PER_PID:
 		default:
@@ -2259,12 +2485,6 @@ void lttng_channel_set_default_attr(struct lttng_domain *domain,
 					DEFAULT_UST_PID_CHANNEL_SWITCH_TIMER;
 			attr->read_timer_interval =
 					DEFAULT_UST_PID_CHANNEL_READ_TIMER;
-			if (extended) {
-				extended->monitor_timer_interval =
-						DEFAULT_UST_PID_CHANNEL_MONITOR_TIMER;
-				extended->blocking_timeout =
-						DEFAULT_UST_PID_CHANNEL_BLOCKING_TIMEOUT;
-			}
 			break;
 		}
 	default:
@@ -2272,6 +2492,11 @@ void lttng_channel_set_default_attr(struct lttng_domain *domain,
 		break;
 	}
 
+	if (extended) {
+		lttng_channel_set_default_extended_attr(domain, extended);
+	}
+
+	/* Reassign the extended pointer. */
 	attr->extended.ptr = extended;
 }
 
@@ -2468,20 +2693,27 @@ int lttng_set_consumer_url(struct lttng_handle *handle,
 	struct lttng_uri *uris = NULL;
 
 	if (handle == NULL || (control_url == NULL && data_url == NULL)) {
-		return -LTTNG_ERR_INVALID;
+		ret = -LTTNG_ERR_INVALID;
+		goto error;
 	}
 
 	memset(&lsm, 0, sizeof(lsm));
 
 	lsm.cmd_type = LTTNG_SET_CONSUMER_URI;
 
-	lttng_ctl_copy_string(lsm.session.name, handle->session_name,
+	ret = lttng_strncpy(lsm.session.name, handle->session_name,
 			sizeof(lsm.session.name));
-	lttng_ctl_copy_lttng_domain(&lsm.domain, &handle->domain);
+	if (ret) {
+		ret = -LTTNG_ERR_INVALID;
+		goto error;
+	}
+
+	COPY_DOMAIN_PACKED(lsm.domain, handle->domain);
 
 	size = uri_parse_str_urls(control_url, data_url, &uris);
 	if (size < 0) {
-		return -LTTNG_ERR_INVALID;
+		ret = -LTTNG_ERR_INVALID;
+		goto error;
 	}
 
 	lsm.u.uri.size = size;
@@ -2490,12 +2722,14 @@ int lttng_set_consumer_url(struct lttng_handle *handle,
 			sizeof(struct lttng_uri) * size, NULL);
 
 	free(uris);
+error:
 	return ret;
 }
 
 /*
  * [OBSOLETE]
  */
+int lttng_enable_consumer(struct lttng_handle *handle);
 int lttng_enable_consumer(struct lttng_handle *handle)
 {
 	return -ENOSYS;
@@ -2504,77 +2738,21 @@ int lttng_enable_consumer(struct lttng_handle *handle)
 /*
  * [OBSOLETE]
  */
+int lttng_disable_consumer(struct lttng_handle *handle);
 int lttng_disable_consumer(struct lttng_handle *handle)
 {
 	return -ENOSYS;
 }
 
 /*
- * This is an extension of create session that is ONLY and SHOULD only be used
- * by the lttng command line program. It exists to avoid using URI parsing in
- * the lttng client.
- *
- * We need the date and time for the trace path subdirectory for the case where
- * the user does NOT define one using either -o or -U. Using the normal
- * lttng_create_session API call, we have no clue on the session daemon side if
- * the URL was generated automatically by the client or define by the user.
- *
- * So this function "wrapper" is hidden from the public API, takes the datetime
- * string and appends it if necessary to the URI subdirectory before sending it
- * to the session daemon.
- *
- * With this extra function, the lttng_create_session call behavior is not
- * changed and the timestamp is appended to the URI on the session daemon side
- * if necessary.
+ * [OBSOLETE]
  */
+int _lttng_create_session_ext(const char *name, const char *url,
+		const char *datetime);
 int _lttng_create_session_ext(const char *name, const char *url,
 		const char *datetime)
 {
-	int ret;
-	ssize_t size;
-	struct lttcomm_session_msg lsm;
-	struct lttng_uri *uris = NULL;
-
-	if (name == NULL || datetime == NULL) {
-		return -LTTNG_ERR_INVALID;
-	}
-
-	memset(&lsm, 0, sizeof(lsm));
-
-	lsm.cmd_type = LTTNG_CREATE_SESSION;
-	lttng_ctl_copy_string(lsm.session.name, name, sizeof(lsm.session.name));
-
-	/* There should never be a data URL. */
-	size = uri_parse_str_urls(url, NULL, &uris);
-	if (size < 0) {
-		ret = -LTTNG_ERR_INVALID;
-		goto error;
-	}
-
-	lsm.u.uri.size = size;
-
-	if (size > 0 && uris[0].dtype != LTTNG_DST_PATH && strlen(uris[0].subdir) == 0) {
-		/* Don't append datetime if the name was automatically created. */
-		if (strncmp(name, DEFAULT_SESSION_NAME "-",
-					strlen(DEFAULT_SESSION_NAME) + 1)) {
-			ret = snprintf(uris[0].subdir, sizeof(uris[0].subdir), "%s-%s",
-					name, datetime);
-		} else {
-			ret = snprintf(uris[0].subdir, sizeof(uris[0].subdir), "%s", name);
-		}
-		if (ret < 0) {
-			PERROR("snprintf uri subdir");
-			ret = -LTTNG_ERR_FATAL;
-			goto error;
-		}
-	}
-
-	ret = lttng_ctl_ask_sessiond_varlen_no_cmd_header(&lsm, uris,
-			sizeof(struct lttng_uri) * size, NULL);
-
-error:
-	free(uris);
-	return ret;
+	return -ENOSYS;
 }
 
 /*
@@ -2595,8 +2773,12 @@ int lttng_data_pending(const char *session_name)
 	memset(&lsm, 0, sizeof(lsm));
 	lsm.cmd_type = LTTNG_DATA_PENDING;
 
-	lttng_ctl_copy_string(lsm.session.name, session_name,
+	ret = lttng_strncpy(lsm.session.name, session_name,
 			sizeof(lsm.session.name));
+	if (ret) {
+		ret = -LTTNG_ERR_INVALID;
+		goto end;
+	}
 
 	ret = lttng_ctl_ask_sessiond(&lsm, (void **) &pending);
 	if (ret < 0) {
@@ -2605,6 +2787,10 @@ int lttng_data_pending(const char *session_name)
 		/* Unexpected payload size */
 		ret = -LTTNG_ERR_INVALID;
 		goto end;
+	} else if (!pending) {
+		/* Internal error. */
+		ret = -LTTNG_ERR_UNK;
+		goto end;
 	}
 
 	ret = (int) *pending;
@@ -2613,152 +2799,6 @@ end:
 	return ret;
 }
 
-/*
- * Create a session exclusively used for snapshot.
- *
- * Returns LTTNG_OK on success or a negative error code.
- */
-int lttng_create_session_snapshot(const char *name, const char *snapshot_url)
-{
-	int ret;
-	ssize_t size;
-	struct lttcomm_session_msg lsm;
-	struct lttng_uri *uris = NULL;
-
-	if (name == NULL) {
-		return -LTTNG_ERR_INVALID;
-	}
-
-	memset(&lsm, 0, sizeof(lsm));
-
-	lsm.cmd_type = LTTNG_CREATE_SESSION_SNAPSHOT;
-	lttng_ctl_copy_string(lsm.session.name, name, sizeof(lsm.session.name));
-
-	size = uri_parse_str_urls(snapshot_url, NULL, &uris);
-	if (size < 0) {
-		return -LTTNG_ERR_INVALID;
-	}
-
-	lsm.u.uri.size = size;
-
-	/*
-	 * If the user does not specify a custom subdir, use the session name.
-	 */
-	if (size > 0 && uris[0].dtype != LTTNG_DST_PATH && strlen(uris[0].subdir) == 0) {
-		ret = snprintf(uris[0].subdir, sizeof(uris[0].subdir), "%s", name);
-		if (ret < 0) {
-			PERROR("snprintf uri subdir");
-			ret = -LTTNG_ERR_FATAL;
-			goto error;
-		}
-	}
-
-	ret = lttng_ctl_ask_sessiond_varlen_no_cmd_header(&lsm, uris,
-			sizeof(struct lttng_uri) * size, NULL);
-
-error:
-	free(uris);
-	return ret;
-}
-
-/*
- * Create a session exclusively used for live.
- *
- * Returns LTTNG_OK on success or a negative error code.
- */
-int lttng_create_session_live(const char *name, const char *url,
-		unsigned int timer_interval)
-{
-	int ret;
-	ssize_t size;
-	struct lttcomm_session_msg lsm;
-	struct lttng_uri *uris = NULL;
-
-	if (name == NULL || timer_interval == 0) {
-		return -LTTNG_ERR_INVALID;
-	}
-
-	memset(&lsm, 0, sizeof(lsm));
-
-	lsm.cmd_type = LTTNG_CREATE_SESSION_LIVE;
-	lttng_ctl_copy_string(lsm.session.name, name, sizeof(lsm.session.name));
-
-	if (url) {
-		size = uri_parse_str_urls(url, NULL, &uris);
-		if (size <= 0) {
-			ret = -LTTNG_ERR_INVALID;
-			goto end;
-		}
-
-		/* file:// is not accepted for live session. */
-		if (uris[0].dtype == LTTNG_DST_PATH) {
-			ret = -LTTNG_ERR_INVALID;
-			goto end;
-		}
-	} else {
-		size = 0;
-	}
-
-	lsm.u.session_live.nb_uri = size;
-	lsm.u.session_live.timer_interval = timer_interval;
-
-	ret = lttng_ctl_ask_sessiond_varlen_no_cmd_header(&lsm, uris,
-			sizeof(struct lttng_uri) * size, NULL);
-
-end:
-	free(uris);
-	return ret;
-}
-
-/*
- * List PIDs in the tracker.
- *
- * enabled is set to whether the PID tracker is enabled.
- * pids is set to an allocated array of PIDs currently tracked. On
- * success, pids must be freed by the caller.
- * nr_pids is set to the number of entries contained by the pids array.
- *
- * Returns 0 on success, else a negative LTTng error code.
- */
-int lttng_list_tracker_pids(struct lttng_handle *handle,
-		int *_enabled, int32_t **_pids, size_t *_nr_pids)
-{
-	int ret;
-	int enabled = 1;
-	struct lttcomm_session_msg lsm;
-	size_t nr_pids;
-	int32_t *pids = NULL;
-
-	if (handle == NULL) {
-		return -LTTNG_ERR_INVALID;
-	}
-
-	memset(&lsm, 0, sizeof(lsm));
-	lsm.cmd_type = LTTNG_LIST_TRACKER_PIDS;
-	lttng_ctl_copy_string(lsm.session.name, handle->session_name,
-			sizeof(lsm.session.name));
-	lttng_ctl_copy_lttng_domain(&lsm.domain, &handle->domain);
-
-	ret = lttng_ctl_ask_sessiond(&lsm, (void **) &pids);
-	if (ret < 0) {
-		return ret;
-	}
-	nr_pids = ret / sizeof(int32_t);
-	if (nr_pids > 0 && !pids) {
-		return -LTTNG_ERR_UNK;
-	}
-	if (nr_pids == 1 && pids[0] == -1) {
-		free(pids);
-		pids = NULL;
-		enabled = 0;
-		nr_pids = 0;
-	}
-	*_enabled = enabled;
-	*_pids = pids;
-	*_nr_pids = nr_pids;
-	return 0;
-}
-
 /*
  * Regenerate the metadata for a session.
  * Return 0 on success, a negative error code on error.
@@ -2776,8 +2816,12 @@ int lttng_regenerate_metadata(const char *session_name)
 	memset(&lsm, 0, sizeof(lsm));
 	lsm.cmd_type = LTTNG_REGENERATE_METADATA;
 
-	lttng_ctl_copy_string(lsm.session.name, session_name,
+	ret = lttng_strncpy(lsm.session.name, session_name,
 			sizeof(lsm.session.name));
+	if (ret) {
+		ret = -LTTNG_ERR_INVALID;
+		goto end;
+	}
 
 	ret = lttng_ctl_ask_sessiond(&lsm, NULL);
 	if (ret < 0) {
@@ -2814,8 +2858,12 @@ int lttng_regenerate_statedump(const char *session_name)
 	memset(&lsm, 0, sizeof(lsm));
 	lsm.cmd_type = LTTNG_REGENERATE_STATEDUMP;
 
-	lttng_ctl_copy_string(lsm.session.name, session_name,
+	ret = lttng_strncpy(lsm.session.name, session_name,
 			sizeof(lsm.session.name));
+	if (ret) {
+		ret = -LTTNG_ERR_INVALID;
+		goto end;
+	}
 
 	ret = lttng_ctl_ask_sessiond(&lsm, NULL);
 	if (ret < 0) {