X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=blobdiff_plain;f=src%2Flib%2Flttng-ctl%2Flttng-ctl.c;h=921db6f598fb30195398750f9a906e355e36707e;hp=a1256e12d981aa5da93c7aed8f7784e24732be9b;hb=347c5ab5500e49fcd356a7e000f44ebce633e1d4;hpb=eacaa7a62c3f2b9a019fd145d69c977fc53144bb

diff --git a/src/lib/lttng-ctl/lttng-ctl.c b/src/lib/lttng-ctl/lttng-ctl.c
index a1256e12d..921db6f59 100644
--- a/src/lib/lttng-ctl/lttng-ctl.c
+++ b/src/lib/lttng-ctl/lttng-ctl.c
@@ -20,6 +20,7 @@
  */
 
 #define _GNU_SOURCE
+#include <assert.h>
 #include <grp.h>
 #include <errno.h>
 #include <stdio.h>
@@ -30,7 +31,31 @@
 #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/filter-ast.h"
+#include "filter/filter-parser.h"
+#include "filter/filter-bytecode.h"
+#include "filter/memstream.h"
+#include "lttng-ctl-helper.h"
+
+#ifdef DEBUG
+static const int print_xml = 1;
+#define dbg_printf(fmt, args...)	\
+	printf("[debug liblttng-ctl] " fmt, ## args)
+#else
+static const int print_xml = 0;
+#define dbg_printf(fmt, args...)				\
+do {								\
+	/* do nothing but check printf format */		\
+	if (0)							\
+		printf("[debug liblttnctl] " fmt, ## args);	\
+} while (0)
+#endif
+
 
 /* Socket to session daemon for communication */
 static int sessiond_socket;
@@ -46,8 +71,6 @@ 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;
@@ -55,7 +78,8 @@ int lttng_opt_verbose;
 /*
  * 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);
@@ -71,23 +95,20 @@ 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:
-			*/
-				memcpy(dst, src, sizeof(struct lttng_domain));
-				break;
-			default:
-				memset(dst, 0, sizeof(struct lttng_domain));
-				dst->type = LTTNG_DOMAIN_KERNEL;
-				break;
+		case LTTNG_DOMAIN_KERNEL:
+		case LTTNG_DOMAIN_UST:
+		case LTTNG_DOMAIN_JUL:
+			memcpy(dst, src, sizeof(struct lttng_domain));
+			break;
+		default:
+			memset(dst, 0, sizeof(struct lttng_domain));
+			break;
 		}
 	}
 }
@@ -103,12 +124,46 @@ 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;
+}
+
+/*
+ * Send var len data to the session daemon.
+ *
+ * On success, returns the number of bytes sent (>=0)
+ * On error, returns -1
+ */
+static int send_session_varlen(void *data, size_t len)
+{
+	int ret;
+
+	if (!connected) {
+		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;
@@ -125,11 +180,14 @@ 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;
@@ -140,12 +198,14 @@ 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);
@@ -200,13 +260,13 @@ 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);
@@ -215,17 +275,20 @@ static int try_connect_sessiond(const char *sock_path)
 	}
 
 	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;
 
@@ -233,15 +296,17 @@ 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);
@@ -257,13 +322,16 @@ 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;
 }
 
 /*
@@ -275,21 +343,29 @@ 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;
 }
 
 /*
@@ -311,10 +387,13 @@ static int disconnect_sessiond(void)
 
 /*
  * Ask the session daemon a specific command and put the data into buf.
+ * Takes extra var. len. data as input to send to the session daemon.
  *
  * Return size of data (only payload, not header) or a negative error code.
  */
-static int ask_sessiond(struct lttcomm_session_msg *lsm, 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;
@@ -323,23 +402,32 @@ static int ask_sessiond(struct lttcomm_session_msg *lsm, void **buf)
 
 	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;
 	}
@@ -368,7 +456,7 @@ static int ask_sessiond(struct lttcomm_session_msg *lsm, void **buf)
 	 * this point, an error is returned and data is freed.
 	 */
 	if (buf == NULL) {
-		ret = -1;
+		ret = -LTTNG_ERR_INVALID;
 		free(data);
 		goto end;
 	}
@@ -388,20 +476,24 @@ end:
 struct lttng_handle *lttng_create_handle(const char *session_name,
 		struct lttng_domain *domain)
 {
-	struct lttng_handle *handle;
+	struct lttng_handle *handle = NULL;
+
+	if (domain == NULL) {
+		goto end;
+	}
 
 	handle = malloc(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;
@@ -412,9 +504,7 @@ end:
  */
 void lttng_destroy_handle(struct lttng_handle *handle)
 {
-	if (handle) {
-		free(handle);
-	}
+	free(handle);
 }
 
 /*
@@ -426,14 +516,19 @@ 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);
 }
 
 /*
@@ -445,40 +540,89 @@ 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;
+	}
 
-	return ask_sessiond(&lsm, NULL);
+	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);
 }
 
 /*
- * 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.
+ * 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 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.
  */
@@ -490,28 +634,30 @@ 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);
 }
 
 /*
@@ -522,37 +668,298 @@ int lttng_add_context(struct lttng_handle *handle,
  */
 int lttng_enable_event(struct lttng_handle *handle,
 		struct lttng_event *ev, const char *channel_name)
+{
+	return lttng_enable_event_with_exclusions(handle, ev, channel_name,
+			NULL, 0, NULL);
+}
+
+/*
+ * 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 JUL filter expression or
+ * NULL if not applicable.
+ *
+ * An event with NO loglevel and the name is * will return NULL.
+ */
+static char *set_jul_filter(const char *filter, struct lttng_event *ev)
+{
+	int err;
+	char *jul_filter = NULL;
+
+	assert(ev);
+
+	/* Don't add filter for the '*' event. */
+	if (ev->name[0] != '*') {
+		if (filter) {
+			err = asprintf(&jul_filter, "%s && logger_name == \"%s\"", filter,
+					ev->name);
+		} else {
+			err = asprintf(&jul_filter, "logger_name == \"%s\"", ev->name);
+		}
+		if (err < 0) {
+			PERROR("asprintf");
+			goto end;
+		}
+	}
+
+	/* Add loglevel filtering if any for the JUL domain. */
+	if (ev->loglevel_type != LTTNG_EVENT_LOGLEVEL_ALL) {
+		char *op;
+
+		if (ev->loglevel_type == LTTNG_EVENT_LOGLEVEL_RANGE) {
+			op = ">=";
+		} else {
+			op = "==";
+		}
+
+		if (filter) {
+			err = asprintf(&jul_filter, "%s && int_loglevel %s %d", filter, op,
+					ev->loglevel);
+		} else {
+			err = asprintf(&jul_filter, "int_loglevel %s %d", op,
+					ev->loglevel);
+		}
+		if (err < 0) {
+			PERROR("asprintf");
+			free(jul_filter);
+			jul_filter = NULL;
+			goto end;
+		}
+	}
+
+end:
+	return jul_filter;
+}
+
+/*
+ * 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_enable_event_with_exclusions(struct lttng_handle *handle,
+		struct lttng_event *ev, const char *channel_name,
+		const char *filter_expression,
+		int exclusion_count, char **exclusion_list)
 {
 	struct lttcomm_session_msg lsm;
+	char *varlen_data, *jul_filter = NULL;
+	int ret = 0;
+	struct filter_parser_ctx *ctx = NULL;
+	FILE *fmem = NULL;
 
 	if (handle == NULL || ev == NULL) {
-		return -1;
+		return -LTTNG_ERR_INVALID;
+	}
+
+	/* 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') {
+		return -LTTNG_ERR_INVALID;
 	}
 
 	memset(&lsm, 0, sizeof(lsm));
 
-	/* If no channel name, we put the default name */
+	/* If no channel name, send empty string. */
 	if (channel_name == NULL) {
-		copy_string(lsm.u.enable.channel_name, DEFAULT_CHANNEL_NAME,
+		lttng_ctl_copy_string(lsm.u.enable.channel_name, "",
 				sizeof(lsm.u.enable.channel_name));
 	} else {
-		copy_string(lsm.u.enable.channel_name, channel_name,
+		lttng_ctl_copy_string(lsm.u.enable.channel_name, channel_name,
 				sizeof(lsm.u.enable.channel_name));
 	}
 
-	copy_lttng_domain(&lsm.domain, &handle->domain);
-
 	if (ev->name[0] != '\0') {
 		lsm.cmd_type = LTTNG_ENABLE_EVENT;
 	} else {
 		lsm.cmd_type = LTTNG_ENABLE_ALL_EVENT;
 	}
+
+	lttng_ctl_copy_lttng_domain(&lsm.domain, &handle->domain);
 	memcpy(&lsm.u.enable.event, ev, sizeof(lsm.u.enable.event));
 
-	copy_string(lsm.session.name, handle->session_name,
+	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) {
+		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) {
+		if (handle->domain.type == LTTNG_DOMAIN_JUL) {
+			/* Setup JUL filter if needed. */
+			filter_expression = set_jul_filter(filter_expression, ev);
+			if (!filter_expression) {
+				goto ask_sessiond;
+			}
+		}
+
+		/*
+		 * 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");
+			free(jul_filter);
+			return -LTTNG_ERR_FILTER_NOMEM;
+		}
+		ctx = filter_parser_ctx_alloc(fmem);
+		if (!ctx) {
+			fprintf(stderr, "Error allocating parser\n");
+			ret = -LTTNG_ERR_FILTER_NOMEM;
+			goto filter_alloc_error;
+		}
+		ret = filter_parser_ctx_append_ast(ctx);
+		if (ret) {
+			fprintf(stderr, "Parse error\n");
+			ret = -LTTNG_ERR_FILTER_INVAL;
+			goto parse_error;
+		}
+		ret = filter_visitor_set_parent(ctx);
+		if (ret) {
+			fprintf(stderr, "Set parent error\n");
+			ret = -LTTNG_ERR_FILTER_INVAL;
+			goto parse_error;
+		}
+		if (print_xml) {
+			ret = filter_visitor_print_xml(ctx, stdout, 0);
+			if (ret) {
+				fflush(stdout);
+				fprintf(stderr, "XML print error\n");
+				ret = -LTTNG_ERR_FILTER_INVAL;
+				goto parse_error;
+			}
+		}
 
-	return ask_sessiond(&lsm, NULL);
+		dbg_printf("Generating IR... ");
+		fflush(stdout);
+		ret = filter_visitor_ir_generate(ctx);
+		if (ret) {
+			fprintf(stderr, "Generate IR error\n");
+			ret = -LTTNG_ERR_FILTER_INVAL;
+			goto parse_error;
+		}
+		dbg_printf("done\n");
+
+		dbg_printf("Validating IR... ");
+		fflush(stdout);
+		ret = filter_visitor_ir_check_binary_op_nesting(ctx);
+		if (ret) {
+			ret = -LTTNG_ERR_FILTER_INVAL;
+			goto parse_error;
+		}
+		dbg_printf("done\n");
+
+		dbg_printf("Generating bytecode... ");
+		fflush(stdout);
+		ret = filter_visitor_bytecode_generate(ctx);
+		if (ret) {
+			fprintf(stderr, "Generate bytecode error\n");
+			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));
+
+		lsm.u.enable.bytecode_len = sizeof(ctx->bytecode->b)
+				+ bytecode_get_len(&ctx->bytecode->b);
+		lsm.u.enable.expression_len = strlen(filter_expression) + 1;
+	}
+
+	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 varlen_alloc_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);
+	}
+	/* 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 (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);
+
+varlen_alloc_error:
+	if (filter_expression) {
+		filter_bytecode_free(ctx);
+		filter_ir_free(ctx);
+		filter_parser_ctx_free(ctx);
+		if (fclose(fmem) != 0) {
+			perror("fclose");
+		}
+	}
+	free(jul_filter);
+	return ret;
+
+parse_error:
+	filter_bytecode_free(ctx);
+	filter_ir_free(ctx);
+	filter_parser_ctx_free(ctx);
+filter_alloc_error:
+	if (fclose(fmem) != 0) {
+		perror("fclose");
+	}
+	free(jul_filter);
+	return ret;
+
+ask_sessiond:
+	ret = lttng_ctl_ask_sessiond(&lsm, NULL);
+	return ret;
 }
 
 /*
@@ -567,32 +974,34 @@ int lttng_disable_event(struct lttng_handle *handle, const char *name,
 	struct lttcomm_session_msg lsm;
 
 	if (handle == NULL) {
-		return -1;
+		return -LTTNG_ERR_INVALID;
 	}
 
 	memset(&lsm, 0, sizeof(lsm));
 
-	if (channel_name) {
-		copy_string(lsm.u.disable.channel_name, channel_name,
+	/* 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 {
-		copy_string(lsm.u.disable.channel_name, DEFAULT_CHANNEL_NAME,
+		lttng_ctl_copy_string(lsm.u.disable.channel_name, channel_name,
 				sizeof(lsm.u.disable.channel_name));
 	}
 
-	copy_lttng_domain(&lsm.domain, &handle->domain);
+	lttng_ctl_copy_lttng_domain(&lsm.domain, &handle->domain);
 
 	if (name != NULL) {
-		copy_string(lsm.u.disable.name, name, sizeof(lsm.u.disable.name));
+		lttng_ctl_copy_string(lsm.u.disable.name, name,
+				sizeof(lsm.u.disable.name));
 		lsm.cmd_type = LTTNG_DISABLE_EVENT;
 	} else {
 		lsm.cmd_type = LTTNG_DISABLE_ALL_EVENT;
 	}
 
-	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);
 }
 
 /*
@@ -608,7 +1017,7 @@ 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));
@@ -617,12 +1026,12 @@ 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);
 }
 
 /*
@@ -635,22 +1044,22 @@ 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);
 
-	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);
 }
 
 /*
@@ -666,13 +1075,14 @@ 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;
 	}
@@ -693,13 +1103,14 @@ 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;
 	}
@@ -713,27 +1124,43 @@ int lttng_list_tracepoint_fields(struct lttng_handle *handle,
  */
 const char *lttng_strerror(int code)
 {
-	/* lttcomm error codes range from -LTTCOMM_OK down to -LTTCOMM_NR */
-	if (code > -LTTCOMM_OK) {
-		return "Ended with errors";
-	}
-
-	return lttcomm_get_readable_code(code);
+	return error_get_str(code);
 }
 
 /*
- *  Create a brand new session using name and path.
- *  Returns size of returned session payload data or a negative error code.
+ * 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(const char *name, const char *path)
+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;
+
+	if (name == NULL) {
+		return -LTTNG_ERR_INVALID;
+	}
+
+	memset(&lsm, 0, sizeof(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));
+	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;
+	}
+
+	lsm.u.uri.size = size;
+
+	ret = lttng_ctl_ask_sessiond_varlen(&lsm, uris,
+			sizeof(struct lttng_uri) * size, NULL);
 
-	return ask_sessiond(&lsm, NULL);
+	free(uris);
+	return ret;
 }
 
 /*
@@ -745,14 +1172,16 @@ 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);
 }
 
 /*
@@ -766,8 +1195,9 @@ 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;
 	}
@@ -788,14 +1218,16 @@ 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;
 	}
@@ -816,16 +1248,17 @@ 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;
 	}
@@ -847,18 +1280,19 @@ 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;
 	}
@@ -874,11 +1308,11 @@ 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;
@@ -894,15 +1328,16 @@ 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);
 }
 
 /*
@@ -919,30 +1354,37 @@ 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;
@@ -965,9 +1407,12 @@ 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);
@@ -980,6 +1425,248 @@ int lttng_session_daemon_alive(void)
 	return 1;
 }
 
+/*
+ * Set URL for a consumer for a session and domain.
+ *
+ * Return 0 on success, else a negative value.
+ */
+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 || (control_url == NULL && data_url == NULL)) {
+		return -LTTNG_ERR_INVALID;
+	}
+
+	memset(&lsm, 0, sizeof(lsm));
+
+	lsm.cmd_type = LTTNG_SET_CONSUMER_URI;
+
+	lttng_ctl_copy_string(lsm.session.name, handle->session_name,
+			sizeof(lsm.session.name));
+	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;
+
+	ret = lttng_ctl_ask_sessiond_varlen(&lsm, uris,
+			sizeof(struct lttng_uri) * size, NULL);
+
+	free(uris);
+	return ret;
+}
+
+/*
+ * [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 (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(&lsm, uris,
+			sizeof(struct lttng_uri) * size, NULL);
+
+error:
+	free(uris);
+	return ret;
+}
+
+/*
+ * 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_data_pending(const char *session_name)
+{
+	int ret;
+	struct lttcomm_session_msg lsm;
+
+	if (session_name == NULL) {
+		return -LTTNG_ERR_INVALID;
+	}
+
+	memset(&lsm, 0, sizeof(lsm));
+	lsm.cmd_type = LTTNG_DATA_PENDING;
+
+	lttng_ctl_copy_string(lsm.session.name, session_name,
+			sizeof(lsm.session.name));
+
+	ret = lttng_ctl_ask_sessiond(&lsm, NULL);
+
+	/*
+	 * The lttng_ctl_ask_sessiond function negate the return code if it's not
+	 * LTTNG_OK so getting -1 means that the reply ret_code was 1 thus meaning
+	 * that the data is available. Yes it is hackish but for now this is the
+	 * only way.
+	 */
+	if (ret == -1) {
+		ret = 1;
+	}
+
+	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;
+
+	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) {
+		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(&lsm, uris,
+			sizeof(struct lttng_uri) * size, NULL);
+
+end:
+	free(uris);
+	return ret;
+}
+
 /*
  * lib constructor
  */
@@ -988,3 +1675,11 @@ static void __attribute__((constructor)) init()
 	/* Set default session group */
 	lttng_set_tracing_group(DEFAULT_TRACING_GROUP);
 }
+
+/*
+ * lib destructor
+ */
+static void __attribute__((destructor)) lttng_ctl_exit()
+{
+	free(tracing_group);
+}