X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=blobdiff_plain;f=src%2Flib%2Flttng-ctl%2Flttng-ctl.c;h=665aba57d7cb80f37656c670fe6d3760747eb7a0;hp=ba0c4c8269a301d31c0183c02592f0d77e363b8e;hb=0c82ac624169ec9ec062f395e55abfe992d0fd91;hpb=95b9bd903e097fa120f5815604d6765f7b0f2596

diff --git a/src/lib/lttng-ctl/lttng-ctl.c b/src/lib/lttng-ctl/lttng-ctl.c
index ba0c4c826..665aba57d 100644
--- a/src/lib/lttng-ctl/lttng-ctl.c
+++ b/src/lib/lttng-ctl/lttng-ctl.c
@@ -19,7 +19,7 @@
  * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
-#define _GNU_SOURCE
+#define _LGPL_SOURCE
 #include <assert.h>
 #include <grp.h>
 #include <errno.h>
@@ -31,19 +31,23 @@
 #include <common/common.h>
 #include <common/defaults.h>
 #include <common/sessiond-comm/sessiond-comm.h>
+#include <common/uri.h>
+#include <common/utils.h>
 #include <lttng/lttng.h>
+#include <lttng/health-internal.h>
 
-#include "filter-ast.h"
-#include "filter-parser.h"
-#include "filter-bytecode.h"
-#include "memstream.h"
+#include "filter/filter-ast.h"
+#include "filter/filter-parser.h"
+#include "filter/filter-bytecode.h"
+#include "filter/memstream.h"
+#include "lttng-ctl-helper.h"
 
 #ifdef DEBUG
-const int print_xml = 1;
+static const int print_xml = 1;
 #define dbg_printf(fmt, args...)	\
 	printf("[debug liblttng-ctl] " fmt, ## args)
 #else
-const int print_xml = 0;
+static const int print_xml = 0;
 #define dbg_printf(fmt, args...)				\
 do {								\
 	/* do nothing but check printf format */		\
@@ -56,7 +60,6 @@ do {								\
 /* Socket to session daemon for communication */
 static int sessiond_socket;
 static char sessiond_sock_path[PATH_MAX];
-static char health_sock_path[PATH_MAX];
 
 /* Variables */
 static char *tracing_group;
@@ -68,16 +71,16 @@ static int connected;
  * Those two variables are used by error.h to silent or control the verbosity of
  * error message. They are global to the library so application linking with it
  * are able to compile correctly and also control verbosity of the library.
- *
- * Note that it is *not* possible to silent ERR() and PERROR() macros.
  */
 int lttng_opt_quiet;
 int lttng_opt_verbose;
+int lttng_opt_mi;
 
 /*
  * Copy string from src to dst and enforce null terminated byte.
  */
-static void copy_string(char *dst, const char *src, size_t len)
+LTTNG_HIDDEN
+void lttng_ctl_copy_string(char *dst, const char *src, size_t len)
 {
 	if (src && dst) {
 		strncpy(dst, src, len);
@@ -93,22 +96,21 @@ static void copy_string(char *dst, const char *src, size_t len)
  *
  * If domain is unknown, default domain will be the kernel.
  */
-static void copy_lttng_domain(struct lttng_domain *dst, struct lttng_domain *src)
+LTTNG_HIDDEN
+void lttng_ctl_copy_lttng_domain(struct lttng_domain *dst,
+		struct lttng_domain *src)
 {
 	if (src && dst) {
 		switch (src->type) {
 		case LTTNG_DOMAIN_KERNEL:
 		case LTTNG_DOMAIN_UST:
-		/*
-		case LTTNG_DOMAIN_UST_EXEC_NAME:
-		case LTTNG_DOMAIN_UST_PID:
-		case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
-		*/
+		case LTTNG_DOMAIN_JUL:
+		case LTTNG_DOMAIN_LOG4J:
+		case LTTNG_DOMAIN_PYTHON:
 			memcpy(dst, src, sizeof(struct lttng_domain));
 			break;
 		default:
 			memset(dst, 0, sizeof(struct lttng_domain));
-			dst->type = LTTNG_DOMAIN_KERNEL;
 			break;
 		}
 	}
@@ -125,12 +127,17 @@ static int send_session_msg(struct lttcomm_session_msg *lsm)
 	int ret;
 
 	if (!connected) {
-		ret = -ENOTCONN;
+		ret = -LTTNG_ERR_NO_SESSIOND;
 		goto end;
 	}
 
+	DBG("LSM cmd type : %d", lsm->cmd_type);
+
 	ret = lttcomm_send_creds_unix_sock(sessiond_socket, lsm,
 			sizeof(struct lttcomm_session_msg));
+	if (ret < 0) {
+		ret = -LTTNG_ERR_FATAL;
+	}
 
 end:
 	return ret;
@@ -147,15 +154,19 @@ static int send_session_varlen(void *data, size_t len)
 	int ret;
 
 	if (!connected) {
-		ret = -ENOTCONN;
+		ret = -LTTNG_ERR_NO_SESSIOND;
 		goto end;
 	}
+
 	if (!data || !len) {
 		ret = 0;
 		goto end;
 	}
 
 	ret = lttcomm_send_unix_sock(sessiond_socket, data, len);
+	if (ret < 0) {
+		ret = -LTTNG_ERR_FATAL;
+	}
 
 end:
 	return ret;
@@ -172,11 +183,14 @@ static int recv_data_sessiond(void *buf, size_t len)
 	int ret;
 
 	if (!connected) {
-		ret = -ENOTCONN;
+		ret = -LTTNG_ERR_NO_SESSIOND;
 		goto end;
 	}
 
 	ret = lttcomm_recv_unix_sock(sessiond_socket, buf, len);
+	if (ret < 0) {
+		ret = -LTTNG_ERR_FATAL;
+	}
 
 end:
 	return ret;
@@ -187,12 +201,14 @@ end:
  *
  *  If yes return 1, else return -1.
  */
-static int check_tracing_group(const char *grp_name)
+LTTNG_HIDDEN
+int lttng_check_tracing_group(void)
 {
 	struct group *grp_tracing;	/* no free(). See getgrnam(3) */
 	gid_t *grp_list;
 	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);
@@ -204,19 +220,19 @@ static int check_tracing_group(const char *grp_name)
 	/* Get number of supplementary group IDs */
 	grp_list_size = getgroups(0, NULL);
 	if (grp_list_size < 0) {
-		perror("getgroups");
+		PERROR("getgroups");
 		goto end;
 	}
 
 	/* Alloc group list of the right size */
-	grp_list = malloc(grp_list_size * sizeof(gid_t));
+	grp_list = zmalloc(grp_list_size * sizeof(gid_t));
 	if (!grp_list) {
-		perror("malloc");
+		PERROR("malloc");
 		goto end;
 	}
 	grp_id = getgroups(grp_list_size, grp_list);
 	if (grp_id < 0) {
-		perror("getgroups");
+		PERROR("getgroups");
 		goto free_list;
 	}
 
@@ -247,32 +263,35 @@ static int try_connect_sessiond(const char *sock_path)
 	ret = access(sock_path, F_OK);
 	if (ret < 0) {
 		/* Not alive */
-		return -1;
+		goto error;
 	}
 
 	ret = lttcomm_connect_unix_sock(sock_path);
 	if (ret < 0) {
 		/* Not alive */
-		return -1;
+		goto error;
 	}
 
 	ret = lttcomm_close_unix_sock(ret);
 	if (ret < 0) {
-		perror("lttcomm_close_unix_sock");
+		PERROR("lttcomm_close_unix_sock");
 	}
 
 	return 0;
+
+error:
+	return -1;
 }
 
 /*
- * Set sessiond socket path by putting it in the global
- * sessiond_sock_path variable.
- * Returns 0 on success,
- * -ENOMEM on failure (the sessiond socket path is somehow too long)
+ * Set sessiond socket path by putting it in the global sessiond_sock_path
+ * variable.
+ *
+ * Returns 0 on success, negative value on failure (the sessiond socket path
+ * is somehow too long or ENOMEM).
  */
 static int set_session_daemon_path(void)
 {
-	int ret;
 	int in_tgroup = 0;	/* In tracing group */
 	uid_t uid;
 
@@ -280,15 +299,17 @@ static int set_session_daemon_path(void)
 
 	if (uid != 0) {
 		/* Are we in the tracing group ? */
-		in_tgroup = check_tracing_group(tracing_group);
+		in_tgroup = lttng_check_tracing_group();
 	}
 
 	if ((uid == 0) || in_tgroup) {
-		copy_string(sessiond_sock_path, DEFAULT_GLOBAL_CLIENT_UNIX_SOCK,
-				sizeof(sessiond_sock_path));
+		lttng_ctl_copy_string(sessiond_sock_path,
+				DEFAULT_GLOBAL_CLIENT_UNIX_SOCK, sizeof(sessiond_sock_path));
 	}
 
 	if (uid != 0) {
+		int ret;
+
 		if (in_tgroup) {
 			/* Tracing group */
 			ret = try_connect_sessiond(sessiond_sock_path);
@@ -304,13 +325,16 @@ static int set_session_daemon_path(void)
 		 * With GNU C >= 2.1, snprintf returns the required size (excluding closing null)
 		 */
 		ret = snprintf(sessiond_sock_path, sizeof(sessiond_sock_path),
-				DEFAULT_HOME_CLIENT_UNIX_SOCK, getenv("HOME"));
+				DEFAULT_HOME_CLIENT_UNIX_SOCK, utils_get_home_dir());
 		if ((ret < 0) || (ret >= sizeof(sessiond_sock_path))) {
-			return -ENOMEM;
+			goto error;
 		}
 	}
 end:
 	return 0;
+
+error:
+	return -1;
 }
 
 /*
@@ -322,21 +346,29 @@ static 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) {
-		return -1; /* set_session_daemon_path() returns -ENOMEM */
+		goto error;
 	}
 
 	/* Connect to the sesssion daemon */
 	ret = lttcomm_connect_unix_sock(sessiond_sock_path);
 	if (ret < 0) {
-		return ret;
+		goto error;
 	}
 
 	sessiond_socket = ret;
 	connected = 1;
 
 	return 0;
+
+error:
+	return -1;
 }
 
 /*
@@ -362,10 +394,9 @@ static int disconnect_sessiond(void)
  *
  * Return size of data (only payload, not header) or a negative error code.
  */
-static int ask_sessiond_varlen(struct lttcomm_session_msg *lsm,
-		void *vardata,
-		size_t varlen,
-		void **buf)
+LTTNG_HIDDEN
+int lttng_ctl_ask_sessiond_varlen(struct lttcomm_session_msg *lsm,
+		void *vardata, size_t varlen, void **buf)
 {
 	int ret;
 	size_t size;
@@ -374,28 +405,32 @@ static int ask_sessiond_varlen(struct lttcomm_session_msg *lsm,
 
 	ret = connect_sessiond();
 	if (ret < 0) {
+		ret = -LTTNG_ERR_NO_SESSIOND;
 		goto end;
 	}
 
 	/* Send command to session daemon */
 	ret = send_session_msg(lsm);
 	if (ret < 0) {
+		/* Ret value is a valid lttng error code. */
 		goto end;
 	}
 	/* Send var len data */
 	ret = send_session_varlen(vardata, varlen);
 	if (ret < 0) {
+		/* Ret value is a valid lttng error code. */
 		goto end;
 	}
 
 	/* Get header from data transmission */
 	ret = recv_data_sessiond(&llm, sizeof(llm));
 	if (ret < 0) {
+		/* Ret value is a valid lttng error code. */
 		goto end;
 	}
 
 	/* Check error code if OK */
-	if (llm.ret_code != LTTCOMM_OK) {
+	if (llm.ret_code != LTTNG_OK) {
 		ret = -llm.ret_code;
 		goto end;
 	}
@@ -410,7 +445,11 @@ static int ask_sessiond_varlen(struct lttcomm_session_msg *lsm,
 		goto end;
 	}
 
-	data = (void*) malloc(size);
+	data = zmalloc(size);
+	if (!data) {
+		ret = -ENOMEM;
+		goto end;
+	}
 
 	/* Get payload data */
 	ret = recv_data_sessiond(data, size);
@@ -424,7 +463,7 @@ static int ask_sessiond_varlen(struct lttcomm_session_msg *lsm,
 	 * this point, an error is returned and data is freed.
 	 */
 	if (buf == NULL) {
-		ret = -1;
+		ret = -LTTNG_ERR_INVALID;
 		free(data);
 		goto end;
 	}
@@ -437,16 +476,6 @@ end:
 	return ret;
 }
 
-/*
- * Ask the session daemon a specific command and put the data into buf.
- *
- * Return size of data (only payload, not header) or a negative error code.
- */
-static int ask_sessiond(struct lttcomm_session_msg *lsm, void **buf)
-{
-	return ask_sessiond_varlen(lsm, NULL, 0, buf);
-}
-
 /*
  * Create lttng handle and return pointer.
  * The returned pointer will be NULL in case of malloc() error.
@@ -454,20 +483,24 @@ static int ask_sessiond(struct lttcomm_session_msg *lsm, void **buf)
 struct lttng_handle *lttng_create_handle(const char *session_name,
 		struct lttng_domain *domain)
 {
-	struct lttng_handle *handle;
+	struct lttng_handle *handle = NULL;
 
-	handle = malloc(sizeof(struct lttng_handle));
+	if (domain == NULL) {
+		goto end;
+	}
+
+	handle = zmalloc(sizeof(struct lttng_handle));
 	if (handle == NULL) {
-		perror("malloc handle");
+		PERROR("malloc handle");
 		goto end;
 	}
 
 	/* Copy session name */
-	copy_string(handle->session_name, session_name,
+	lttng_ctl_copy_string(handle->session_name, session_name,
 			sizeof(handle->session_name));
 
 	/* Copy lttng domain */
-	copy_lttng_domain(&handle->domain, domain);
+	lttng_ctl_copy_lttng_domain(&handle->domain, domain);
 
 end:
 	return handle;
@@ -478,9 +511,7 @@ end:
  */
 void lttng_destroy_handle(struct lttng_handle *handle)
 {
-	if (handle) {
-		free(handle);
-	}
+	free(handle);
 }
 
 /*
@@ -492,14 +523,19 @@ int lttng_register_consumer(struct lttng_handle *handle,
 {
 	struct lttcomm_session_msg lsm;
 
+	if (handle == NULL || socket_path == NULL) {
+		return -LTTNG_ERR_INVALID;
+	}
+
+	memset(&lsm, 0, sizeof(lsm));
 	lsm.cmd_type = LTTNG_REGISTER_CONSUMER;
-	copy_string(lsm.session.name, handle->session_name,
+	lttng_ctl_copy_string(lsm.session.name, handle->session_name,
 			sizeof(lsm.session.name));
-	copy_lttng_domain(&lsm.domain, &handle->domain);
+	lttng_ctl_copy_lttng_domain(&lsm.domain, &handle->domain);
 
-	copy_string(lsm.u.reg.path, socket_path, sizeof(lsm.u.reg.path));
+	lttng_ctl_copy_string(lsm.u.reg.path, socket_path, sizeof(lsm.u.reg.path));
 
-	return ask_sessiond(&lsm, NULL);
+	return lttng_ctl_ask_sessiond(&lsm, NULL);
 }
 
 /*
@@ -511,40 +547,89 @@ int lttng_start_tracing(const char *session_name)
 	struct lttcomm_session_msg lsm;
 
 	if (session_name == NULL) {
-		return -1;
+		return -LTTNG_ERR_INVALID;
 	}
 
+	memset(&lsm, 0, sizeof(lsm));
 	lsm.cmd_type = LTTNG_START_TRACE;
 
-	copy_string(lsm.session.name, session_name, sizeof(lsm.session.name));
+	lttng_ctl_copy_string(lsm.session.name, session_name,
+			sizeof(lsm.session.name));
 
-	return ask_sessiond(&lsm, NULL);
+	return lttng_ctl_ask_sessiond(&lsm, NULL);
 }
 
 /*
- *  Stop tracing for all traces of the session.
- *  Returns size of returned session payload data or a negative error code.
+ * Stop tracing for all traces of the session.
  */
-int lttng_stop_tracing(const char *session_name)
+static int _lttng_stop_tracing(const char *session_name, int wait)
 {
+	int ret, data_ret;
 	struct lttcomm_session_msg lsm;
 
 	if (session_name == NULL) {
-		return -1;
+		return -LTTNG_ERR_INVALID;
 	}
 
+	memset(&lsm, 0, sizeof(lsm));
 	lsm.cmd_type = LTTNG_STOP_TRACE;
 
-	copy_string(lsm.session.name, session_name, sizeof(lsm.session.name));
+	lttng_ctl_copy_string(lsm.session.name, session_name,
+			sizeof(lsm.session.name));
+
+	ret = lttng_ctl_ask_sessiond(&lsm, NULL);
+	if (ret < 0 && ret != -LTTNG_ERR_TRACE_ALREADY_STOPPED) {
+		goto error;
+	}
+
+	if (!wait) {
+		goto end;
+	}
+
+	/* Check for data availability */
+	do {
+		data_ret = lttng_data_pending(session_name);
+		if (data_ret < 0) {
+			/* Return the data available call error. */
+			ret = data_ret;
+			goto error;
+		}
+
+		/*
+		 * Data sleep time before retrying (in usec). Don't sleep if the call
+		 * returned value indicates availability.
+		 */
+		if (data_ret) {
+			usleep(DEFAULT_DATA_AVAILABILITY_WAIT_TIME);
+		}
+	} while (data_ret != 0);
+
+end:
+error:
+	return ret;
+}
+
+/*
+ * Stop tracing and wait for data availability.
+ */
+int lttng_stop_tracing(const char *session_name)
+{
+	return _lttng_stop_tracing(session_name, 1);
+}
 
-	return ask_sessiond(&lsm, NULL);
+/*
+ * Stop tracing but _don't_ wait for data availability.
+ */
+int lttng_stop_tracing_no_wait(const char *session_name)
+{
+	return _lttng_stop_tracing(session_name, 0);
 }
 
 /*
- * Add context to event and/or channel.
- * If event_name is NULL, the context is applied to all events of the channel.
- * If channel_name is NULL, a lookup of the event's channel is done.
- * If both are NULL, the context is applied to all events of all channels.
+ * Add context to a channel.
+ *
+ * If the given channel is NULL, add the contexts to all channels.
+ * The event_name param is ignored.
  *
  * Returns the size of the returned payload data or a negative error code.
  */
@@ -556,28 +641,30 @@ int lttng_add_context(struct lttng_handle *handle,
 
 	/* Safety check. Both are mandatory */
 	if (handle == NULL || ctx == NULL) {
-		return -1;
+		return -LTTNG_ERR_INVALID;
 	}
 
 	memset(&lsm, 0, sizeof(lsm));
 
 	lsm.cmd_type = LTTNG_ADD_CONTEXT;
 
-	/* Copy channel name */
-	copy_string(lsm.u.context.channel_name, channel_name,
-			sizeof(lsm.u.context.channel_name));
-	/* Copy event name */
-	copy_string(lsm.u.context.event_name, event_name,
-			sizeof(lsm.u.context.event_name));
+	/* 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));
+	}
 
-	copy_lttng_domain(&lsm.domain, &handle->domain);
+	lttng_ctl_copy_lttng_domain(&lsm.domain, &handle->domain);
 
 	memcpy(&lsm.u.context.ctx, ctx, sizeof(struct lttng_event_context));
 
-	copy_string(lsm.session.name, handle->session_name,
+	lttng_ctl_copy_string(lsm.session.name, handle->session_name,
 			sizeof(lsm.session.name));
 
-	return ask_sessiond(&lsm, NULL);
+	return lttng_ctl_ask_sessiond(&lsm, NULL);
 }
 
 /*
@@ -589,88 +676,132 @@ int lttng_add_context(struct lttng_handle *handle,
 int lttng_enable_event(struct lttng_handle *handle,
 		struct lttng_event *ev, const char *channel_name)
 {
-	struct lttcomm_session_msg lsm;
+	return lttng_enable_event_with_exclusions(handle, ev, channel_name,
+			NULL, 0, NULL);
+}
 
-	if (handle == NULL || ev == NULL) {
-		return -1;
+/*
+ * Create or enable an event with a filter expression.
+ *
+ * Return negative error value on error.
+ * Return size of returned session payload data if OK.
+ */
+int lttng_enable_event_with_filter(struct lttng_handle *handle,
+		struct lttng_event *event, const char *channel_name,
+		const char *filter_expression)
+{
+	return lttng_enable_event_with_exclusions(handle, event, channel_name,
+			filter_expression, 0, NULL);
+}
+
+/*
+ * Depending on the event, return a newly allocated agent filter expression or
+ * NULL if not applicable.
+ *
+ * An event with NO loglevel and the name is * will return NULL.
+ */
+static char *set_agent_filter(const char *filter, struct lttng_event *ev)
+{
+	int err;
+	char *agent_filter = NULL;
+
+	assert(ev);
+
+	/* Don't add filter for the '*' event. */
+	if (ev->name[0] != '*') {
+		if (filter) {
+			err = asprintf(&agent_filter, "(%s) && (logger_name == \"%s\")", filter,
+					ev->name);
+		} else {
+			err = asprintf(&agent_filter, "logger_name == \"%s\"", ev->name);
+		}
+		if (err < 0) {
+			PERROR("asprintf");
+			goto error;
+		}
 	}
 
-	memset(&lsm, 0, sizeof(lsm));
+	/* Add loglevel filtering if any for the JUL domain. */
+	if (ev->loglevel_type != LTTNG_EVENT_LOGLEVEL_ALL) {
+		char *op;
 
-	/* If no channel name, we put the default name */
-	if (channel_name == NULL) {
-		copy_string(lsm.u.enable.channel_name, DEFAULT_CHANNEL_NAME,
-				sizeof(lsm.u.enable.channel_name));
-	} else {
-		copy_string(lsm.u.enable.channel_name, channel_name,
-				sizeof(lsm.u.enable.channel_name));
-	}
+		if (ev->loglevel_type == LTTNG_EVENT_LOGLEVEL_RANGE) {
+			op = ">=";
+		} else {
+			op = "==";
+		}
 
-	copy_lttng_domain(&lsm.domain, &handle->domain);
+		if (filter || agent_filter) {
+			char *new_filter;
 
-	if (ev->name[0] != '\0') {
-		lsm.cmd_type = LTTNG_ENABLE_EVENT;
-	} else {
-		lsm.cmd_type = LTTNG_ENABLE_ALL_EVENT;
+			err = asprintf(&new_filter, "(%s) && (int_loglevel %s %d)",
+					agent_filter ? agent_filter : filter, op,
+					ev->loglevel);
+			if (agent_filter) {
+				free(agent_filter);
+			}
+			agent_filter = new_filter;
+		} else {
+			err = asprintf(&agent_filter, "int_loglevel %s %d", op,
+					ev->loglevel);
+		}
+		if (err < 0) {
+			PERROR("asprintf");
+			goto error;
+		}
 	}
-	memcpy(&lsm.u.enable.event, ev, sizeof(lsm.u.enable.event));
 
-	copy_string(lsm.session.name, handle->session_name,
-			sizeof(lsm.session.name));
-
-	return ask_sessiond(&lsm, NULL);
+	return agent_filter;
+error:
+	free(agent_filter);
+	return NULL;
 }
 
 /*
- * set filter for an event
- * Return negative error value on error.
- * Return size of returned session payload data if OK.
+ * Generate the filter bytecode from a given filter expression string. Put the
+ * newly allocated parser context in ctxp and populate the lsm object with the
+ * expression len.
+ *
+ * Return 0 on success else a LTTNG_ERR_* code and ctxp is untouched.
  */
-
-int lttng_set_event_filter(struct lttng_handle *handle,
-		const char *event_name, const char *channel_name,
-		const char *filter_expression)
+static int generate_filter(char *filter_expression,
+		struct lttcomm_session_msg *lsm, struct filter_parser_ctx **ctxp)
 {
-	struct lttcomm_session_msg lsm;
-	struct filter_parser_ctx *ctx;
-	FILE *fmem;
-	int ret = 0;
+	int ret;
+	struct filter_parser_ctx *ctx = NULL;
+	FILE *fmem = NULL;
 
-	/* Safety check. */
-	if (handle == NULL) {
-		return -1;
-	}
-
-	if (!filter_expression) {
-		return 0;
-	}
+	assert(filter_expression);
+	assert(lsm);
+	assert(ctxp);
 
 	/*
-	 * casting const to non-const, as the underlying function will
-	 * use it in read-only mode.
+	 * Casting const to non-const, as the underlying function will use it in
+	 * read-only mode.
 	 */
 	fmem = lttng_fmemopen((void *) filter_expression,
 			strlen(filter_expression), "r");
 	if (!fmem) {
 		fprintf(stderr, "Error opening memory as stream\n");
-		return -ENOMEM;
+		ret = -LTTNG_ERR_FILTER_NOMEM;
+		goto error;
 	}
 	ctx = filter_parser_ctx_alloc(fmem);
 	if (!ctx) {
 		fprintf(stderr, "Error allocating parser\n");
-		ret = -ENOMEM;
-		goto alloc_error;
+		ret = -LTTNG_ERR_FILTER_NOMEM;
+		goto filter_alloc_error;
 	}
 	ret = filter_parser_ctx_append_ast(ctx);
 	if (ret) {
 		fprintf(stderr, "Parse error\n");
-		ret = -EINVAL;
+		ret = -LTTNG_ERR_FILTER_INVAL;
 		goto parse_error;
 	}
 	ret = filter_visitor_set_parent(ctx);
 	if (ret) {
 		fprintf(stderr, "Set parent error\n");
-		ret = -EINVAL;
+		ret = -LTTNG_ERR_FILTER_INVAL;
 		goto parse_error;
 	}
 	if (print_xml) {
@@ -678,7 +809,7 @@ int lttng_set_event_filter(struct lttng_handle *handle,
 		if (ret) {
 			fflush(stdout);
 			fprintf(stderr, "XML print error\n");
-			ret = -EINVAL;
+			ret = -LTTNG_ERR_FILTER_INVAL;
 			goto parse_error;
 		}
 	}
@@ -688,7 +819,7 @@ int lttng_set_event_filter(struct lttng_handle *handle,
 	ret = filter_visitor_ir_generate(ctx);
 	if (ret) {
 		fprintf(stderr, "Generate IR error\n");
-		ret = -EINVAL;
+		ret = -LTTNG_ERR_FILTER_INVAL;
 		goto parse_error;
 	}
 	dbg_printf("done\n");
@@ -697,7 +828,13 @@ int lttng_set_event_filter(struct lttng_handle *handle,
 	fflush(stdout);
 	ret = filter_visitor_ir_check_binary_op_nesting(ctx);
 	if (ret) {
-		ret = -EINVAL;
+		ret = -LTTNG_ERR_FILTER_INVAL;
+		goto parse_error;
+	}
+	/* Validate strings used as literals in the expression */
+	ret = filter_visitor_ir_validate_string(ctx);
+	if (ret) {
+		ret = -LTTNG_ERR_FILTER_INVAL;
 		goto parse_error;
 	}
 	dbg_printf("done\n");
@@ -707,91 +844,378 @@ int lttng_set_event_filter(struct lttng_handle *handle,
 	ret = filter_visitor_bytecode_generate(ctx);
 	if (ret) {
 		fprintf(stderr, "Generate bytecode error\n");
-		ret = -EINVAL;
+		ret = -LTTNG_ERR_FILTER_INVAL;
 		goto parse_error;
 	}
 	dbg_printf("done\n");
 	dbg_printf("Size of bytecode generated: %u bytes.\n",
-		bytecode_get_len(&ctx->bytecode->b));
-
-	memset(&lsm, 0, sizeof(lsm));
-
-	lsm.cmd_type = LTTNG_SET_FILTER;
-
-	/* Copy channel name */
-	copy_string(lsm.u.filter.channel_name, channel_name,
-			sizeof(lsm.u.filter.channel_name));
-	/* Copy event name */
-	copy_string(lsm.u.filter.event_name, event_name,
-			sizeof(lsm.u.filter.event_name));
-	lsm.u.filter.bytecode_len = sizeof(ctx->bytecode->b)
-			+ bytecode_get_len(&ctx->bytecode->b);
-
-	copy_lttng_domain(&lsm.domain, &handle->domain);
+			bytecode_get_len(&ctx->bytecode->b));
 
-	copy_string(lsm.session.name, handle->session_name,
-			sizeof(lsm.session.name));
-
-	ret = ask_sessiond_varlen(&lsm, &ctx->bytecode->b,
-				lsm.u.filter.bytecode_len, NULL);
+	lsm->u.enable.bytecode_len = sizeof(ctx->bytecode->b)
+		+ bytecode_get_len(&ctx->bytecode->b);
+	lsm->u.enable.expression_len = strlen(filter_expression) + 1;
 
-	filter_bytecode_free(ctx);
-	filter_ir_free(ctx);
-	filter_parser_ctx_free(ctx);
+	/* No need to keep the memory stream. */
 	if (fclose(fmem) != 0) {
-		perror("fclose");
+		PERROR("fclose");
 	}
-	return ret;
+
+	*ctxp = ctx;
+	return 0;
 
 parse_error:
-	filter_bytecode_free(ctx);
 	filter_ir_free(ctx);
 	filter_parser_ctx_free(ctx);
-alloc_error:
+filter_alloc_error:
 	if (fclose(fmem) != 0) {
-		perror("fclose");
+		PERROR("fclose");
 	}
+error:
 	return ret;
 }
 
 /*
- *  Disable event(s) of a channel and domain.
- *  If no event name is specified, all events are disabled.
- *  If no channel name is specified, the default 'channel0' is used.
- *  Returns size of returned session payload data or a negative error code.
+ * Enable event(s) for a channel, possibly with exclusions and a filter.
+ * If no event name is specified, all events are enabled.
+ * If no channel name is specified, the default name is used.
+ * If filter expression is not NULL, the filter is set for the event.
+ * If exclusion count is not zero, the exclusions are set for the event.
+ * Returns size of returned session payload data or a negative error code.
  */
-int lttng_disable_event(struct lttng_handle *handle, const char *name,
-		const char *channel_name)
+int lttng_enable_event_with_exclusions(struct lttng_handle *handle,
+		struct lttng_event *ev, const char *channel_name,
+		const char *original_filter_expression,
+		int exclusion_count, char **exclusion_list)
 {
 	struct lttcomm_session_msg lsm;
+	char *varlen_data;
+	int ret = 0;
+	unsigned int free_filter_expression = 0;
+	struct filter_parser_ctx *ctx = NULL;
+	/*
+	 * Cast as non-const since we may replace the filter expression
+	 * by a dynamically allocated string. Otherwise, the original
+	 * string is not modified.
+	 */
+	char *filter_expression = (char *) original_filter_expression;
 
-	if (handle == NULL) {
-		return -1;
+	if (handle == NULL || ev == NULL) {
+		ret = -LTTNG_ERR_INVALID;
+		goto error;
+	}
+
+	/* Empty filter string will always be rejected by the parser
+	 * anyway, so treat this corner-case early to eliminate
+	 * lttng_fmemopen error for 0-byte allocation.
+	 */
+	if (filter_expression && filter_expression[0] == '\0') {
+		ret = -LTTNG_ERR_INVALID;
+		goto error;
 	}
 
 	memset(&lsm, 0, sizeof(lsm));
 
-	if (channel_name) {
-		copy_string(lsm.u.disable.channel_name, channel_name,
-				sizeof(lsm.u.disable.channel_name));
+	/* 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 {
-		copy_string(lsm.u.disable.channel_name, DEFAULT_CHANNEL_NAME,
-				sizeof(lsm.u.disable.channel_name));
+		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));
+	}
+
+	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;
+
+	/*
+	 * For the JUL domain, a filter is enforced except for the enable all
+	 * event. This is done to avoid having the event in all sessions thus
+	 * filtering by logger name.
+	 */
+	if (exclusion_count == 0 && 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 either a filter or some exclusions, 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
+			|| handle->domain.type == LTTNG_DOMAIN_PYTHON) {
+		if (handle->domain.type == LTTNG_DOMAIN_JUL ||
+				handle->domain.type == LTTNG_DOMAIN_LOG4J ||
+				handle->domain.type == LTTNG_DOMAIN_PYTHON) {
+			char *agent_filter;
+
+			/* Setup JUL filter if needed. */
+			agent_filter = set_agent_filter(filter_expression, ev);
+			if (!agent_filter) {
+				if (!filter_expression) {
+					/* No JUL and no filter, just skip everything below. */
+					goto ask_sessiond;
+				}
+			} else {
+				/*
+				 * With an agent filter, the original filter has been added to
+				 * it thus replace the filter expression.
+				 */
+				filter_expression = agent_filter;
+				free_filter_expression = 1;
+			}
+		}
+
+		ret = generate_filter(filter_expression, &lsm, &ctx);
+		if (ret) {
+			goto filter_error;
+		}
+	}
+
+	varlen_data = zmalloc(lsm.u.enable.bytecode_len
+			+ lsm.u.enable.expression_len
+			+ LTTNG_SYMBOL_NAME_LEN * exclusion_count);
+	if (!varlen_data) {
+		ret = -LTTNG_ERR_EXCLUSION_NOMEM;
+		goto mem_error;
+	}
+
+	/* Put exclusion names first in the data */
+	while (exclusion_count--) {
+		strncpy(varlen_data + LTTNG_SYMBOL_NAME_LEN * exclusion_count,
+			*(exclusion_list + exclusion_count),
+			LTTNG_SYMBOL_NAME_LEN - 1);
+	}
+	/* Add filter expression next */
+	if (lsm.u.enable.expression_len != 0) {
+		memcpy(varlen_data
+			+ LTTNG_SYMBOL_NAME_LEN * lsm.u.enable.exclusion_count,
+			filter_expression,
+			lsm.u.enable.expression_len);
+	}
+	/* Add filter bytecode next */
+	if (ctx && lsm.u.enable.bytecode_len != 0) {
+		memcpy(varlen_data
+			+ LTTNG_SYMBOL_NAME_LEN * lsm.u.enable.exclusion_count
+			+ lsm.u.enable.expression_len,
+			&ctx->bytecode->b,
+			lsm.u.enable.bytecode_len);
+	}
+
+	ret = lttng_ctl_ask_sessiond_varlen(&lsm, varlen_data,
+			(LTTNG_SYMBOL_NAME_LEN * lsm.u.enable.exclusion_count) +
+			lsm.u.enable.bytecode_len + lsm.u.enable.expression_len, NULL);
+	free(varlen_data);
+
+mem_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 it is
+		 * not the original filter expression received as a parameter.
+		 */
+		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);
+	return ret;
+}
+
+int lttng_disable_event_ext(struct lttng_handle *handle,
+		struct lttng_event *ev, const char *channel_name,
+		const char *original_filter_expression)
+{
+	struct lttcomm_session_msg lsm;
+	char *varlen_data;
+	int ret = 0;
+	unsigned int free_filter_expression = 0;
+	struct filter_parser_ctx *ctx = NULL;
+	/*
+	 * Cast as non-const since we may replace the filter expression
+	 * by a dynamically allocated string. Otherwise, the original
+	 * string is not modified.
+	 */
+	char *filter_expression = (char *) original_filter_expression;
+
+	if (handle == NULL || ev == NULL) {
+		ret = -LTTNG_ERR_INVALID;
+		goto error;
 	}
 
-	copy_lttng_domain(&lsm.domain, &handle->domain);
+	/* Empty filter string will always be rejected by the parser
+	 * anyway, so treat this corner-case early to eliminate
+	 * lttng_fmemopen error for 0-byte allocation.
+	 */
+	if (filter_expression && filter_expression[0] == '\0') {
+		ret = -LTTNG_ERR_INVALID;
+		goto error;
+	}
+
+	memset(&lsm, 0, sizeof(lsm));
 
-	if (name != NULL) {
-		copy_string(lsm.u.disable.name, name, sizeof(lsm.u.disable.name));
-		lsm.cmd_type = LTTNG_DISABLE_EVENT;
+	/* 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 {
-		lsm.cmd_type = LTTNG_DISABLE_ALL_EVENT;
+		lttng_ctl_copy_string(lsm.u.disable.channel_name, channel_name,
+				sizeof(lsm.u.disable.channel_name));
 	}
 
-	copy_string(lsm.session.name, handle->session_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
+			|| handle->domain.type == LTTNG_DOMAIN_PYTHON) {
+		if (handle->domain.type == LTTNG_DOMAIN_JUL ||
+				handle->domain.type == LTTNG_DOMAIN_LOG4J ||
+				handle->domain.type == LTTNG_DOMAIN_PYTHON) {
+			char *agent_filter;
+
+			/* Setup JUL filter if needed. */
+			agent_filter = set_agent_filter(filter_expression, ev);
+			if (!agent_filter) {
+				if (!filter_expression) {
+					/* No JUL and no filter, just skip everything below. */
+					goto ask_sessiond;
+				}
+			} else {
+				/*
+				 * With a JUL filter, the original filter has been added to it
+				 * thus replace the filter expression.
+				 */
+				filter_expression = agent_filter;
+				free_filter_expression = 1;
+			}
+		}
+
+		ret = generate_filter(filter_expression, &lsm, &ctx);
+		if (ret) {
+			goto filter_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;
+	}
+
+	/* Add filter expression */
+	if (lsm.u.disable.expression_len != 0) {
+		memcpy(varlen_data,
+			filter_expression,
+			lsm.u.disable.expression_len);
+	}
+	/* 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);
+	}
+
+	ret = lttng_ctl_ask_sessiond_varlen(&lsm, varlen_data,
+			lsm.u.disable.bytecode_len + lsm.u.disable.expression_len, NULL);
+	free(varlen_data);
 
-	return ask_sessiond(&lsm, NULL);
+mem_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 it is
+		 * not the original filter expression received as a parameter.
+		 */
+		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);
+	return ret;
+}
+
+/*
+ *  Disable event(s) of a channel and domain.
+ *  If no event name is specified, all events are disabled.
+ *  If no channel name is specified, the default 'channel0' is used.
+ *  Returns size of returned session payload data or a negative error code.
+ */
+int lttng_disable_event(struct lttng_handle *handle, const char *name,
+		const char *channel_name)
+{
+	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);
 }
 
 /*
@@ -807,7 +1231,7 @@ int lttng_enable_channel(struct lttng_handle *handle,
 	 * NULL arguments are forbidden. No default values.
 	 */
 	if (handle == NULL || chan == NULL) {
-		return -1;
+		return -LTTNG_ERR_INVALID;
 	}
 
 	memset(&lsm, 0, sizeof(lsm));
@@ -816,12 +1240,12 @@ int lttng_enable_channel(struct lttng_handle *handle,
 
 	lsm.cmd_type = LTTNG_ENABLE_CHANNEL;
 
-	copy_lttng_domain(&lsm.domain, &handle->domain);
+	lttng_ctl_copy_lttng_domain(&lsm.domain, &handle->domain);
 
-	copy_string(lsm.session.name, handle->session_name,
+	lttng_ctl_copy_string(lsm.session.name, handle->session_name,
 			sizeof(lsm.session.name));
 
-	return ask_sessiond(&lsm, NULL);
+	return lttng_ctl_ask_sessiond(&lsm, NULL);
 }
 
 /*
@@ -834,22 +1258,78 @@ int lttng_disable_channel(struct lttng_handle *handle, const char *name)
 
 	/* Safety check. Both are mandatory */
 	if (handle == NULL || name == NULL) {
-		return -1;
+		return -LTTNG_ERR_INVALID;
 	}
 
 	memset(&lsm, 0, sizeof(lsm));
 
 	lsm.cmd_type = LTTNG_DISABLE_CHANNEL;
 
-	copy_string(lsm.u.disable.channel_name, name,
+	lttng_ctl_copy_string(lsm.u.disable.channel_name, name,
 			sizeof(lsm.u.disable.channel_name));
 
-	copy_lttng_domain(&lsm.domain, &handle->domain);
+	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;
+	}
+
+	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);
+}
+
+/*
+ *  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;
+	}
+
+	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);
 
-	copy_string(lsm.session.name, handle->session_name,
+	lttng_ctl_copy_string(lsm.session.name, handle->session_name,
 			sizeof(lsm.session.name));
 
-	return ask_sessiond(&lsm, NULL);
+	return lttng_ctl_ask_sessiond(&lsm, NULL);
 }
 
 /*
@@ -865,13 +1345,14 @@ int lttng_list_tracepoints(struct lttng_handle *handle,
 	struct lttcomm_session_msg lsm;
 
 	if (handle == NULL) {
-		return -1;
+		return -LTTNG_ERR_INVALID;
 	}
 
+	memset(&lsm, 0, sizeof(lsm));
 	lsm.cmd_type = LTTNG_LIST_TRACEPOINTS;
-	copy_lttng_domain(&lsm.domain, &handle->domain);
+	lttng_ctl_copy_lttng_domain(&lsm.domain, &handle->domain);
 
-	ret = ask_sessiond(&lsm, (void **) events);
+	ret = lttng_ctl_ask_sessiond(&lsm, (void **) events);
 	if (ret < 0) {
 		return ret;
 	}
@@ -892,13 +1373,14 @@ int lttng_list_tracepoint_fields(struct lttng_handle *handle,
 	struct lttcomm_session_msg lsm;
 
 	if (handle == NULL) {
-		return -1;
+		return -LTTNG_ERR_INVALID;
 	}
 
+	memset(&lsm, 0, sizeof(lsm));
 	lsm.cmd_type = LTTNG_LIST_TRACEPOINT_FIELDS;
-	copy_lttng_domain(&lsm.domain, &handle->domain);
+	lttng_ctl_copy_lttng_domain(&lsm.domain, &handle->domain);
 
-	ret = ask_sessiond(&lsm, (void **) fields);
+	ret = lttng_ctl_ask_sessiond(&lsm, (void **) fields);
 	if (ret < 0) {
 		return ret;
 	}
@@ -907,65 +1389,77 @@ int lttng_list_tracepoint_fields(struct lttng_handle *handle,
 }
 
 /*
- *  Returns a human readable string describing
- *  the error code (a negative value).
+ *  Lists all available kernel system calls. Allocates and sets the contents of
+ *  the events array.
+ *
+ *  Returns the number of lttng_event entries in events; on error, returns a
+ *  negative value.
  */
-const char *lttng_strerror(int code)
+int lttng_list_syscalls(struct lttng_event **events)
 {
-	/* lttcomm error codes range from -LTTCOMM_OK down to -LTTCOMM_NR */
-	if (code > -LTTCOMM_OK) {
-		return "Ended with errors";
+	int ret;
+	struct lttcomm_session_msg lsm;
+
+	if (!events) {
+		return -LTTNG_ERR_INVALID;
+	}
+
+	memset(&lsm, 0, sizeof(lsm));
+	lsm.cmd_type = LTTNG_LIST_SYSCALLS;
+	/* Force kernel domain for system calls. */
+	lsm.domain.type = LTTNG_DOMAIN_KERNEL;
+
+	ret = lttng_ctl_ask_sessiond(&lsm, (void **) events);
+	if (ret < 0) {
+		return ret;
 	}
 
-	return lttcomm_get_readable_code(code);
+	return ret / sizeof(struct lttng_event);
 }
 
 /*
- *  Create a brand new session using name and path.
- *  Returns size of returned session payload data or a negative error code.
+ *  Returns a human readable string describing
+ *  the error code (a negative value).
  */
-int lttng_create_session(const char *name, const char *path)
+const char *lttng_strerror(int code)
 {
-	struct lttcomm_session_msg lsm;
-
-	lsm.cmd_type = LTTNG_CREATE_SESSION;
-	copy_string(lsm.session.name, name, sizeof(lsm.session.name));
-	copy_string(lsm.session.path, path, sizeof(lsm.session.path));
-
-	return ask_sessiond(&lsm, NULL);
+	return error_get_str(code);
 }
 
 /*
- * Create a new tracing session using a name, URIs and a consumer enable flag.
+ * Create a brand new session using name and url for destination.
+ *
+ * Returns LTTNG_OK on success or a negative error code.
  */
-int lttng_create_session_uri(const char *name, struct lttng_uri *ctrl_uri,
-		struct lttng_uri *data_uri, unsigned int enable_consumer)
+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;
 
-	/* Name and ctrl_uri are mandatory */
-	if (name == NULL || ctrl_uri == NULL) {
-		return -1;
+	if (name == NULL) {
+		return -LTTNG_ERR_INVALID;
 	}
 
-	lsm.cmd_type = LTTNG_CREATE_SESSION_URI;
+	memset(&lsm, 0, sizeof(lsm));
 
-	copy_string(lsm.session.name, name, sizeof(lsm.session.name));
-	/* Anything bigger than zero, the consumer(s) will be enabled */
-	lsm.u.create_uri.enable_consumer = enable_consumer;
-	memcpy(&lsm.u.create_uri.ctrl_uri, ctrl_uri,
-			sizeof(lsm.u.create_uri.ctrl_uri));
-	if (data_uri) {
-		/*
-		 * The only possible scenario where data_uri is NULL is for a local
-		 * consumer where the output is at a specified path name on the
-		 * filesystem.
-		 */
-		memcpy(&lsm.u.create_uri.data_uri, data_uri,
-				sizeof(lsm.u.create_uri.data_uri));
+	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;
 	}
 
-	return ask_sessiond(&lsm, NULL);
+	lsm.u.uri.size = size;
+
+	ret = lttng_ctl_ask_sessiond_varlen(&lsm, uris,
+			sizeof(struct lttng_uri) * size, NULL);
+
+	free(uris);
+	return ret;
 }
 
 /*
@@ -977,14 +1471,16 @@ int lttng_destroy_session(const char *session_name)
 	struct lttcomm_session_msg lsm;
 
 	if (session_name == NULL) {
-		return -1;
+		return -LTTNG_ERR_INVALID;
 	}
 
+	memset(&lsm, 0, sizeof(lsm));
 	lsm.cmd_type = LTTNG_DESTROY_SESSION;
 
-	copy_string(lsm.session.name, session_name, sizeof(lsm.session.name));
+	lttng_ctl_copy_string(lsm.session.name, session_name,
+			sizeof(lsm.session.name));
 
-	return ask_sessiond(&lsm, NULL);
+	return lttng_ctl_ask_sessiond(&lsm, NULL);
 }
 
 /*
@@ -998,8 +1494,9 @@ int lttng_list_sessions(struct lttng_session **sessions)
 	int ret;
 	struct lttcomm_session_msg lsm;
 
+	memset(&lsm, 0, sizeof(lsm));
 	lsm.cmd_type = LTTNG_LIST_SESSIONS;
-	ret = ask_sessiond(&lsm, (void**) sessions);
+	ret = lttng_ctl_ask_sessiond(&lsm, (void**) sessions);
 	if (ret < 0) {
 		return ret;
 	}
@@ -1007,6 +1504,26 @@ int lttng_list_sessions(struct lttng_session **sessions)
 	return ret / sizeof(struct lttng_session);
 }
 
+int lttng_set_session_shm_path(const char *session_name,
+		const char *shm_path)
+{
+	struct lttcomm_session_msg lsm;
+
+	if (session_name == NULL) {
+		return -LTTNG_ERR_INVALID;
+	}
+
+	memset(&lsm, 0, sizeof(lsm));
+	lsm.cmd_type = LTTNG_SET_SESSION_SHM_PATH;
+
+	lttng_ctl_copy_string(lsm.session.name, session_name,
+			sizeof(lsm.session.name));
+	lttng_ctl_copy_string(lsm.u.set_shm_path.shm_path, shm_path,
+			sizeof(lsm.u.set_shm_path.shm_path));
+
+	return lttng_ctl_ask_sessiond(&lsm, NULL);
+}
+
 /*
  *  Ask the session daemon for all available domains of a session.
  *  Sets the contents of the domains array.
@@ -1020,14 +1537,16 @@ int lttng_list_domains(const char *session_name,
 	struct lttcomm_session_msg lsm;
 
 	if (session_name == NULL) {
-		return -1;
+		return -LTTNG_ERR_INVALID;
 	}
 
+	memset(&lsm, 0, sizeof(lsm));
 	lsm.cmd_type = LTTNG_LIST_DOMAINS;
 
-	copy_string(lsm.session.name, session_name, sizeof(lsm.session.name));
+	lttng_ctl_copy_string(lsm.session.name, session_name,
+			sizeof(lsm.session.name));
 
-	ret = ask_sessiond(&lsm, (void**) domains);
+	ret = lttng_ctl_ask_sessiond(&lsm, (void**) domains);
 	if (ret < 0) {
 		return ret;
 	}
@@ -1048,16 +1567,17 @@ int lttng_list_channels(struct lttng_handle *handle,
 	struct lttcomm_session_msg lsm;
 
 	if (handle == NULL) {
-		return -1;
+		return -LTTNG_ERR_INVALID;
 	}
 
+	memset(&lsm, 0, sizeof(lsm));
 	lsm.cmd_type = LTTNG_LIST_CHANNELS;
-	copy_string(lsm.session.name, handle->session_name,
+	lttng_ctl_copy_string(lsm.session.name, handle->session_name,
 			sizeof(lsm.session.name));
 
-	copy_lttng_domain(&lsm.domain, &handle->domain);
+	lttng_ctl_copy_lttng_domain(&lsm.domain, &handle->domain);
 
-	ret = ask_sessiond(&lsm, (void**) channels);
+	ret = lttng_ctl_ask_sessiond(&lsm, (void**) channels);
 	if (ret < 0) {
 		return ret;
 	}
@@ -1079,18 +1599,19 @@ int lttng_list_events(struct lttng_handle *handle,
 
 	/* Safety check. An handle and channel name are mandatory */
 	if (handle == NULL || channel_name == NULL) {
-		return -1;
+		return -LTTNG_ERR_INVALID;
 	}
 
+	memset(&lsm, 0, sizeof(lsm));
 	lsm.cmd_type = LTTNG_LIST_EVENTS;
-	copy_string(lsm.session.name, handle->session_name,
+	lttng_ctl_copy_string(lsm.session.name, handle->session_name,
 			sizeof(lsm.session.name));
-	copy_string(lsm.u.list.channel_name, channel_name,
+	lttng_ctl_copy_string(lsm.u.list.channel_name, channel_name,
 			sizeof(lsm.u.list.channel_name));
 
-	copy_lttng_domain(&lsm.domain, &handle->domain);
+	lttng_ctl_copy_lttng_domain(&lsm.domain, &handle->domain);
 
-	ret = ask_sessiond(&lsm, (void**) events);
+	ret = lttng_ctl_ask_sessiond(&lsm, (void**) events);
 	if (ret < 0) {
 		return ret;
 	}
@@ -1106,11 +1627,11 @@ int lttng_list_events(struct lttng_handle *handle,
 int lttng_set_tracing_group(const char *name)
 {
 	if (name == NULL) {
-		return -1;
+		return -LTTNG_ERR_INVALID;
 	}
 
 	if (asprintf(&tracing_group, "%s", name) < 0) {
-		return -ENOMEM;
+		return -LTTNG_ERR_FATAL;
 	}
 
 	return 0;
@@ -1126,15 +1647,16 @@ int lttng_calibrate(struct lttng_handle *handle,
 
 	/* Safety check. NULL pointer are forbidden */
 	if (handle == NULL || calibrate == NULL) {
-		return -1;
+		return -LTTNG_ERR_INVALID;
 	}
 
+	memset(&lsm, 0, sizeof(lsm));
 	lsm.cmd_type = LTTNG_CALIBRATE;
-	copy_lttng_domain(&lsm.domain, &handle->domain);
+	lttng_ctl_copy_lttng_domain(&lsm.domain, &handle->domain);
 
 	memcpy(&lsm.u.calibrate, calibrate, sizeof(lsm.u.calibrate));
 
-	return ask_sessiond(&lsm, NULL);
+	return lttng_ctl_ask_sessiond(&lsm, NULL);
 }
 
 /*
@@ -1151,30 +1673,37 @@ void lttng_channel_set_default_attr(struct lttng_domain *domain,
 
 	memset(attr, 0, sizeof(struct lttng_channel_attr));
 
+	/* Same for all domains. */
+	attr->overwrite = DEFAULT_CHANNEL_OVERWRITE;
+	attr->tracefile_size = DEFAULT_CHANNEL_TRACEFILE_SIZE;
+	attr->tracefile_count = DEFAULT_CHANNEL_TRACEFILE_COUNT;
+
 	switch (domain->type) {
 	case LTTNG_DOMAIN_KERNEL:
-		attr->overwrite = DEFAULT_CHANNEL_OVERWRITE;
-		attr->switch_timer_interval = DEFAULT_CHANNEL_SWITCH_TIMER;
-		attr->read_timer_interval = DEFAULT_CHANNEL_READ_TIMER;
-
-		attr->subbuf_size = DEFAULT_KERNEL_CHANNEL_SUBBUF_SIZE;
+		attr->switch_timer_interval = DEFAULT_KERNEL_CHANNEL_SWITCH_TIMER;
+		attr->read_timer_interval = DEFAULT_KERNEL_CHANNEL_READ_TIMER;
+		attr->subbuf_size = default_get_kernel_channel_subbuf_size();
 		attr->num_subbuf = DEFAULT_KERNEL_CHANNEL_SUBBUF_NUM;
 		attr->output = DEFAULT_KERNEL_CHANNEL_OUTPUT;
 		break;
 	case LTTNG_DOMAIN_UST:
-#if 0
-	case LTTNG_DOMAIN_UST_EXEC_NAME:
-	case LTTNG_DOMAIN_UST_PID:
-	case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
-#endif
-		attr->overwrite = DEFAULT_CHANNEL_OVERWRITE;
-		attr->switch_timer_interval = DEFAULT_CHANNEL_SWITCH_TIMER;
-		attr->read_timer_interval = DEFAULT_CHANNEL_READ_TIMER;
-
-		attr->subbuf_size = DEFAULT_UST_CHANNEL_SUBBUF_SIZE;
-		attr->num_subbuf = DEFAULT_UST_CHANNEL_SUBBUF_NUM;
-		attr->output = DEFAULT_UST_CHANNEL_OUTPUT;
-		break;
+		switch (domain->buf_type) {
+		case LTTNG_BUFFER_PER_UID:
+			attr->subbuf_size = default_get_ust_uid_channel_subbuf_size();
+			attr->num_subbuf = DEFAULT_UST_UID_CHANNEL_SUBBUF_NUM;
+			attr->output = DEFAULT_UST_UID_CHANNEL_OUTPUT;
+			attr->switch_timer_interval = DEFAULT_UST_UID_CHANNEL_SWITCH_TIMER;
+			attr->read_timer_interval = DEFAULT_UST_UID_CHANNEL_READ_TIMER;
+			break;
+		case LTTNG_BUFFER_PER_PID:
+		default:
+			attr->subbuf_size = default_get_ust_pid_channel_subbuf_size();
+			attr->num_subbuf = DEFAULT_UST_PID_CHANNEL_SUBBUF_NUM;
+			attr->output = DEFAULT_UST_PID_CHANNEL_OUTPUT;
+			attr->switch_timer_interval = DEFAULT_UST_PID_CHANNEL_SWITCH_TIMER;
+			attr->read_timer_interval = DEFAULT_UST_PID_CHANNEL_READ_TIMER;
+			break;
+		}
 	default:
 		/* Default behavior: leave set to 0. */
 		break;
@@ -1197,9 +1726,12 @@ int lttng_session_daemon_alive(void)
 		return ret;
 	}
 
-	if (strlen(sessiond_sock_path) == 0) {
-		/* No socket path set. Weird error */
-		return -1;
+	if (*sessiond_sock_path == '\0') {
+		/*
+		 * No socket path set. Weird error which means the constructor was not
+		 * called.
+		 */
+		assert(0);
 	}
 
 	ret = try_connect_sessiond(sessiond_sock_path);
@@ -1213,163 +1745,292 @@ int lttng_session_daemon_alive(void)
 }
 
 /*
- * Set URI for a consumer for a session and domain.
+ * Set URL for a consumer for a session and domain.
  *
  * Return 0 on success, else a negative value.
  */
-int lttng_set_consumer_uri(struct lttng_handle *handle, struct lttng_uri *uri)
+int lttng_set_consumer_url(struct lttng_handle *handle,
+		const char *control_url, const char *data_url)
 {
+	int ret;
+	ssize_t size;
 	struct lttcomm_session_msg lsm;
+	struct lttng_uri *uris = NULL;
 
-	if (handle == NULL || uri == NULL) {
-		return -1;
+	if (handle == NULL || (control_url == NULL && data_url == NULL)) {
+		return -LTTNG_ERR_INVALID;
 	}
 
+	memset(&lsm, 0, sizeof(lsm));
+
 	lsm.cmd_type = LTTNG_SET_CONSUMER_URI;
 
-	copy_string(lsm.session.name, handle->session_name,
+	lttng_ctl_copy_string(lsm.session.name, handle->session_name,
 			sizeof(lsm.session.name));
-	copy_lttng_domain(&lsm.domain, &handle->domain);
+	lttng_ctl_copy_lttng_domain(&lsm.domain, &handle->domain);
+
+	size = uri_parse_str_urls(control_url, data_url, &uris);
+	if (size < 0) {
+		return -LTTNG_ERR_INVALID;
+	}
+
+	lsm.u.uri.size = size;
 
-	memcpy(&lsm.u.uri, uri, sizeof(lsm.u.uri));
+	ret = lttng_ctl_ask_sessiond_varlen(&lsm, uris,
+			sizeof(struct lttng_uri) * size, NULL);
 
-	return ask_sessiond(&lsm, NULL);
+	free(uris);
+	return ret;
 }
 
 /*
- * Enable consumer for a session and domain.
- *
- * Return 0 on success, else a negative value.
+ * [OBSOLETE]
  */
 int lttng_enable_consumer(struct lttng_handle *handle)
 {
+	return -ENOSYS;
+}
+
+/*
+ * [OBSOLETE]
+ */
+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.
+ */
+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 (handle == NULL) {
-		return -1;
+	if (name == NULL || datetime == NULL) {
+		return -LTTNG_ERR_INVALID;
 	}
 
-	lsm.cmd_type = LTTNG_ENABLE_CONSUMER;
+	memset(&lsm, 0, sizeof(lsm));
 
-	copy_string(lsm.session.name, handle->session_name,
-			sizeof(lsm.session.name));
-	copy_lttng_domain(&lsm.domain, &handle->domain);
+	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;
 
-	return ask_sessiond(&lsm, NULL);
+	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(&lsm, uris,
+			sizeof(struct lttng_uri) * size, NULL);
+
+error:
+	free(uris);
+	return ret;
 }
 
 /*
- * Disable consumer for a session and domain.
- *
- * Return 0 on success, else a negative value.
+ * For a given session name, this call checks if the data is ready to be read
+ * or is still being extracted by the consumer(s) hence not ready to be used by
+ * any readers.
  */
-int lttng_disable_consumer(struct lttng_handle *handle)
+int lttng_data_pending(const char *session_name)
 {
+	int ret;
 	struct lttcomm_session_msg lsm;
+	uint8_t *pending = NULL;
 
-	if (handle == NULL) {
-		return -1;
+	if (session_name == NULL) {
+		return -LTTNG_ERR_INVALID;
 	}
 
-	lsm.cmd_type = LTTNG_DISABLE_CONSUMER;
+	memset(&lsm, 0, sizeof(lsm));
+	lsm.cmd_type = LTTNG_DATA_PENDING;
 
-	copy_string(lsm.session.name, handle->session_name,
+	lttng_ctl_copy_string(lsm.session.name, session_name,
 			sizeof(lsm.session.name));
-	copy_lttng_domain(&lsm.domain, &handle->domain);
 
-	return ask_sessiond(&lsm, NULL);
+	ret = lttng_ctl_ask_sessiond(&lsm, (void **) &pending);
+	if (ret < 0) {
+		goto end;
+	} else if (ret != 1) {
+		/* Unexpected payload size */
+		ret = -LTTNG_ERR_INVALID;
+		goto end;
+	}
+
+	ret = (int) *pending;
+end:
+	free(pending);
+	return ret;
 }
 
 /*
- * Set health socket path by putting it in the global health_sock_path
- * variable.
+ * Create a session exclusively used for snapshot.
  *
- * Returns 0 on success or assert(0) on ENOMEM.
+ * Returns LTTNG_OK on success or a negative error code.
  */
-static int set_health_socket_path(void)
+int lttng_create_session_snapshot(const char *name, const char *snapshot_url)
 {
 	int ret;
-	int in_tgroup = 0;	/* In tracing group */
-	uid_t uid;
-	const char *home;
+	ssize_t size;
+	struct lttcomm_session_msg lsm;
+	struct lttng_uri *uris = NULL;
 
-	uid = getuid();
+	if (name == NULL) {
+		return -LTTNG_ERR_INVALID;
+	}
 
-	if (uid != 0) {
-		/* Are we in the tracing group ? */
-		in_tgroup = check_tracing_group(tracing_group);
+	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;
 	}
 
-	if ((uid == 0) || in_tgroup) {
-		copy_string(health_sock_path, DEFAULT_GLOBAL_HEALTH_UNIX_SOCK,
-				sizeof(health_sock_path));
+	lsm.u.uri.size = size;
+
+	ret = lttng_ctl_ask_sessiond_varlen(&lsm, uris,
+			sizeof(struct lttng_uri) * size, NULL);
+
+	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;
 	}
 
-	if (uid != 0) {
-		/*
-		 * With GNU C <  2.1, snprintf returns -1 if the target buffer is too small;
-		 * With GNU C >= 2.1, snprintf returns the required size (excluding closing null)
-		 */
-		home = getenv("HOME");
-		if (home == NULL) {
-			/* Fallback in /tmp .. */
-			home = "/tmp";
+	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;
 		}
 
-		ret = snprintf(health_sock_path, sizeof(health_sock_path),
-				DEFAULT_HOME_HEALTH_UNIX_SOCK, home);
-		if ((ret < 0) || (ret >= sizeof(health_sock_path))) {
-			/* ENOMEM at this point... just kill the control lib. */
-			assert(0);
+		/* file:// is not accepted for live session. */
+		if (uris[0].dtype == LTTNG_DST_PATH) {
+			ret = -LTTNG_ERR_INVALID;
+			goto end;
 		}
+	} else {
+		size = 0;
 	}
 
-	return 0;
+	lsm.u.session_live.nb_uri = size;
+	lsm.u.session_live.timer_interval = timer_interval;
+
+	ret = lttng_ctl_ask_sessiond_varlen(&lsm, uris,
+			sizeof(struct lttng_uri) * size, NULL);
+
+end:
+	free(uris);
+	return ret;
 }
 
 /*
- * Check session daemon health for a specific health component.
+ * List PIDs in the tracker.
  *
- * Return 0 if health is OK or else 1 if BAD. A return value of -1 indicate
- * that the control library was not able to connect to the session daemon
- * health socket.
+ * 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.
  *
- * Any other positive value is an lttcomm error which can be translate with
- * lttng_strerror().
+ * Returns 0 on success, else a negative LTTng error code.
  */
-int lttng_health_check(enum lttng_health_component c)
+int lttng_list_tracker_pids(struct lttng_handle *handle,
+		int *_enabled, int32_t **_pids, size_t *_nr_pids)
 {
-	int sock, ret;
-	struct lttcomm_health_msg msg;
-	struct lttcomm_health_data reply;
+	int ret;
+	int enabled = 1;
+	struct lttcomm_session_msg lsm;
+	size_t nr_pids;
+	int32_t *pids;
 
-	/* Connect to the sesssion daemon */
-	sock = lttcomm_connect_unix_sock(health_sock_path);
-	if (sock < 0) {
-		ret = -1;
-		goto error;
+	if (handle == NULL) {
+		return -LTTNG_ERR_INVALID;
 	}
 
-	msg.cmd = LTTNG_HEALTH_CHECK;
-	msg.component = c;
+	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 = lttcomm_send_unix_sock(sock, (void *)&msg, sizeof(msg));
+	ret = lttng_ctl_ask_sessiond(&lsm, (void **) &pids);
 	if (ret < 0) {
-		goto close_error;
+		return ret;
 	}
-
-	ret = lttcomm_recv_unix_sock(sock, (void *)&reply, sizeof(reply));
-	if (ret < 0) {
-		goto close_error;
+	nr_pids = ret / sizeof(int32_t);
+	if (nr_pids == 1 && pids[0] == -1) {
+		free(pids);
+		pids = NULL;
+		enabled = 0;
+		nr_pids = 0;
 	}
-
-	ret = reply.ret_code;
-
-close_error:
-	close(sock);
-
-error:
-	return ret;
+	*_enabled = enabled;
+	*_pids = pids;
+	*_nr_pids = nr_pids;
+	return 0;
 }
 
 /*
@@ -1379,6 +2040,12 @@ static void __attribute__((constructor)) init()
 {
 	/* Set default session group */
 	lttng_set_tracing_group(DEFAULT_TRACING_GROUP);
-	/* Set socket for health check */
-	(void) set_health_socket_path();
+}
+
+/*
+ * lib destructor
+ */
+static void __attribute__((destructor)) lttng_ctl_exit()
+{
+	free(tracing_group);
 }