X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=blobdiff_plain;f=src%2Flib%2Flttng-ctl%2Flttng-ctl.c;h=3863aa1ceb9de16836d4edc6c55d908fd289e08f;hp=b6487b7c25f51c490ecb3f3bf28343244a6b680d;hb=5288612f2dc35805e861d0648bf75304c91bfeee;hpb=44a5e5eb99f1d8b528f83fda5585677a3882f5f5

diff --git a/src/lib/lttng-ctl/lttng-ctl.c b/src/lib/lttng-ctl/lttng-ctl.c
index b6487b7c2..3863aa1ce 100644
--- a/src/lib/lttng-ctl/lttng-ctl.c
+++ b/src/lib/lttng-ctl/lttng-ctl.c
@@ -31,19 +31,22 @@
 #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 "filter-parser.h"
-#include "filter-ast.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 */		\
@@ -68,8 +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;
@@ -77,7 +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);
@@ -93,22 +95,18 @@ 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;
 		}
 	}
@@ -125,12 +123,17 @@ 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 +150,19 @@ 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 +179,14 @@ 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;
@@ -247,13 +257,13 @@ 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);
@@ -262,17 +272,20 @@ 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;
 
@@ -284,11 +297,13 @@ static int set_session_daemon_path(void)
 	}
 
 	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 +319,16 @@ 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 +340,29 @@ 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 +388,9 @@ 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 +399,32 @@ 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;
 	}
@@ -424,7 +453,7 @@ 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 +466,6 @@ 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 +473,24 @@ 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;
+
+	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;
@@ -478,9 +501,7 @@ end:
  */
 void lttng_destroy_handle(struct lttng_handle *handle)
 {
-	if (handle) {
-		free(handle);
-	}
+	free(handle);
 }
 
 /*
@@ -492,14 +513,18 @@ int lttng_register_consumer(struct lttng_handle *handle,
 {
 	struct lttcomm_session_msg lsm;
 
+	if (handle == NULL || socket_path == NULL) {
+		return -LTTNG_ERR_INVALID;
+	}
+
 	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 +536,92 @@ int lttng_start_tracing(const char *session_name)
 	struct lttcomm_session_msg lsm;
 
 	if (session_name == NULL) {
-		return -1;
+		return -LTTNG_ERR_INVALID;
 	}
 
 	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;
 	}
 
 	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;
+	}
+
+	_MSG("Waiting for data availability");
+
+	/* 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);
+			_MSG(".");
+		}
+	} while (data_ret != 0);
+
+	MSG("");
+
+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.
  */
@@ -556,7 +633,7 @@ 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));
@@ -564,20 +641,17 @@ int lttng_add_context(struct lttng_handle *handle,
 	lsm.cmd_type = LTTNG_ADD_CONTEXT;
 
 	/* Copy channel name */
-	copy_string(lsm.u.context.channel_name, channel_name,
+	lttng_ctl_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));
 
-	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);
 }
 
 /*
@@ -592,21 +666,21 @@ int lttng_enable_event(struct lttng_handle *handle,
 	struct lttcomm_session_msg lsm;
 
 	if (handle == NULL || ev == NULL) {
-		return -1;
+		return -LTTNG_ERR_INVALID;
 	}
 
 	memset(&lsm, 0, sizeof(lsm));
 
 	/* If no channel name, we put the default name */
 	if (channel_name == NULL) {
-		copy_string(lsm.u.enable.channel_name, DEFAULT_CHANNEL_NAME,
+		lttng_ctl_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,
+		lttng_ctl_copy_string(lsm.u.enable.channel_name, channel_name,
 				sizeof(lsm.u.enable.channel_name));
 	}
 
-	copy_lttng_domain(&lsm.domain, &handle->domain);
+	lttng_ctl_copy_lttng_domain(&lsm.domain, &handle->domain);
 
 	if (ev->name[0] != '\0') {
 		lsm.cmd_type = LTTNG_ENABLE_EVENT;
@@ -615,20 +689,20 @@ int lttng_enable_event(struct lttng_handle *handle,
 	}
 	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));
 
-	return ask_sessiond(&lsm, NULL);
+	return lttng_ctl_ask_sessiond(&lsm, NULL);
 }
 
 /*
- * set filter for an event
+ * 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_set_event_filter(struct lttng_handle *handle,
-		const char *event_name, const char *channel_name,
+int lttng_enable_event_with_filter(struct lttng_handle *handle,
+		struct lttng_event *event, const char *channel_name,
 		const char *filter_expression)
 {
 	struct lttcomm_session_msg lsm;
@@ -636,13 +710,21 @@ int lttng_set_event_filter(struct lttng_handle *handle,
 	FILE *fmem;
 	int ret = 0;
 
-	/* Safety check. */
-	if (handle == NULL) {
-		return -1;
+	if (!filter_expression) {
+		/*
+		 * Fall back to normal event enabling if no filter
+		 * specified.
+		 */
+		return lttng_enable_event(handle, event, channel_name);
 	}
 
-	if (!filter_expression) {
-		return 0;
+	/*
+	 * 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 (handle == NULL || filter_expression[0] == '\0') {
+		return -LTTNG_ERR_INVALID;
 	}
 
 	/*
@@ -653,24 +735,24 @@ int lttng_set_event_filter(struct lttng_handle *handle,
 			strlen(filter_expression), "r");
 	if (!fmem) {
 		fprintf(stderr, "Error opening memory as stream\n");
-		return -ENOMEM;
+		return -LTTNG_ERR_FILTER_NOMEM;
 	}
 	ctx = filter_parser_ctx_alloc(fmem);
 	if (!ctx) {
 		fprintf(stderr, "Error allocating parser\n");
-		ret = -ENOMEM;
+		ret = -LTTNG_ERR_FILTER_NOMEM;
 		goto 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 +760,7 @@ 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 +770,7 @@ 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 +779,7 @@ 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;
 	}
 	dbg_printf("done\n");
@@ -707,7 +789,7 @@ 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");
@@ -716,24 +798,26 @@ int lttng_set_event_filter(struct lttng_handle *handle,
 
 	memset(&lsm, 0, sizeof(lsm));
 
-	lsm.cmd_type = LTTNG_SET_FILTER;
+	lsm.cmd_type = LTTNG_ENABLE_EVENT_WITH_FILTER;
 
 	/* Copy channel name */
-	copy_string(lsm.u.filter.channel_name, channel_name,
-			sizeof(lsm.u.filter.channel_name));
+	lttng_ctl_copy_string(lsm.u.enable.channel_name, channel_name,
+			sizeof(lsm.u.enable.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)
+	if (event) {
+		memcpy(&lsm.u.enable.event, event, sizeof(lsm.u.enable.event));
+	}
+
+	lsm.u.enable.bytecode_len = sizeof(ctx->bytecode->b)
 			+ bytecode_get_len(&ctx->bytecode->b);
 
-	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));
 
-	ret = ask_sessiond_varlen(&lsm, &ctx->bytecode->b,
-				lsm.u.filter.bytecode_len, NULL);
+	ret = lttng_ctl_ask_sessiond_varlen(&lsm, &ctx->bytecode->b,
+				lsm.u.enable.bytecode_len, NULL);
 
 	filter_bytecode_free(ctx);
 	filter_ir_free(ctx);
@@ -766,32 +850,33 @@ 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,
+		lttng_ctl_copy_string(lsm.u.disable.channel_name, 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, DEFAULT_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);
 }
 
 /*
@@ -807,7 +892,7 @@ 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 +901,12 @@ 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 +919,22 @@ 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);
 }
 
 /*
@@ -865,13 +950,13 @@ int lttng_list_tracepoints(struct lttng_handle *handle,
 	struct lttcomm_session_msg lsm;
 
 	if (handle == NULL) {
-		return -1;
+		return -LTTNG_ERR_INVALID;
 	}
 
 	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 +977,13 @@ int lttng_list_tracepoint_fields(struct lttng_handle *handle,
 	struct lttcomm_session_msg lsm;
 
 	if (handle == NULL) {
-		return -1;
+		return -LTTNG_ERR_INVALID;
 	}
 
 	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;
 	}
@@ -912,60 +997,43 @@ 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;
 
-	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));
+	if (name == NULL) {
+		return -LTTNG_ERR_INVALID;
+	}
 
-	return ask_sessiond(&lsm, NULL);
-}
+	memset(&lsm, 0, sizeof(lsm));
 
-/*
- * Create a new tracing session using a name, URIs and a consumer enable flag.
- */
-int lttng_create_session_uri(const char *name, struct lttng_uri *ctrl_uri,
-		struct lttng_uri *data_uri, unsigned int enable_consumer)
-{
-	struct lttcomm_session_msg lsm;
+	lsm.cmd_type = LTTNG_CREATE_SESSION;
+	lttng_ctl_copy_string(lsm.session.name, name, sizeof(lsm.session.name));
 
-	/* Name and ctrl_uri are mandatory */
-	if (name == NULL || ctrl_uri == NULL) {
-		return -1;
+	/* There should never be a data URL */
+	size = uri_parse_str_urls(url, NULL, &uris);
+	if (size < 0) {
+		return -LTTNG_ERR_INVALID;
 	}
 
-	lsm.cmd_type = LTTNG_CREATE_SESSION_URI;
+	lsm.u.uri.size = size;
 
-	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));
-	}
+	ret = lttng_ctl_ask_sessiond_varlen(&lsm, uris,
+			sizeof(struct lttng_uri) * size, NULL);
 
-	return ask_sessiond(&lsm, NULL);
+	free(uris);
+	return ret;
 }
 
 /*
@@ -977,14 +1045,15 @@ int lttng_destroy_session(const char *session_name)
 	struct lttcomm_session_msg lsm;
 
 	if (session_name == NULL) {
-		return -1;
+		return -LTTNG_ERR_INVALID;
 	}
 
 	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);
 }
 
 /*
@@ -999,7 +1068,7 @@ int lttng_list_sessions(struct lttng_session **sessions)
 	struct lttcomm_session_msg 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;
 	}
@@ -1020,14 +1089,15 @@ int lttng_list_domains(const char *session_name,
 	struct lttcomm_session_msg lsm;
 
 	if (session_name == NULL) {
-		return -1;
+		return -LTTNG_ERR_INVALID;
 	}
 
 	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 +1118,16 @@ int lttng_list_channels(struct lttng_handle *handle,
 	struct lttcomm_session_msg lsm;
 
 	if (handle == NULL) {
-		return -1;
+		return -LTTNG_ERR_INVALID;
 	}
 
 	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 +1149,18 @@ 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;
 	}
 
 	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 +1176,11 @@ 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 +1196,15 @@ int lttng_calibrate(struct lttng_handle *handle,
 
 	/* Safety check. NULL pointer are forbidden */
 	if (handle == NULL || calibrate == NULL) {
-		return -1;
+		return -LTTNG_ERR_INVALID;
 	}
 
 	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 +1221,37 @@ 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 +1274,12 @@ 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);
@@ -1213,71 +1293,58 @@ 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;
+	}
 
-	memcpy(&lsm.u.uri, uri, sizeof(lsm.u.uri));
+	lsm.u.uri.size = size;
 
-	return ask_sessiond(&lsm, NULL);
+	ret = lttng_ctl_ask_sessiond_varlen(&lsm, uris,
+			sizeof(struct lttng_uri) * size, 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)
 {
-	struct lttcomm_session_msg lsm;
-
-	if (handle == NULL) {
-		return -1;
-	}
-
-	lsm.cmd_type = LTTNG_ENABLE_CONSUMER;
-
-	copy_string(lsm.session.name, handle->session_name,
-			sizeof(lsm.session.name));
-	copy_lttng_domain(&lsm.domain, &handle->domain);
-
-	return ask_sessiond(&lsm, NULL);
+	return -ENOSYS;
 }
 
 /*
- * Disable consumer for a session and domain.
- *
- * Return 0 on success, else a negative value.
+ * [OBSOLETE]
  */
 int lttng_disable_consumer(struct lttng_handle *handle)
 {
-	struct lttcomm_session_msg lsm;
-
-	if (handle == NULL) {
-		return -1;
-	}
-
-	lsm.cmd_type = LTTNG_DISABLE_CONSUMER;
-
-	copy_string(lsm.session.name, handle->session_name,
-			sizeof(lsm.session.name));
-	copy_lttng_domain(&lsm.domain, &handle->domain);
-
-	return ask_sessiond(&lsm, NULL);
+	return -ENOSYS;
 }
 
 /*
@@ -1288,7 +1355,6 @@ int lttng_disable_consumer(struct lttng_handle *handle)
  */
 static int set_health_socket_path(void)
 {
-	int ret;
 	int in_tgroup = 0;	/* In tracing group */
 	uid_t uid;
 	const char *home;
@@ -1301,16 +1367,18 @@ static int set_health_socket_path(void)
 	}
 
 	if ((uid == 0) || in_tgroup) {
-		copy_string(health_sock_path, DEFAULT_GLOBAL_HEALTH_UNIX_SOCK,
-				sizeof(health_sock_path));
+		lttng_ctl_copy_string(health_sock_path,
+				DEFAULT_GLOBAL_HEALTH_UNIX_SOCK, sizeof(health_sock_path));
 	}
 
 	if (uid != 0) {
+		int ret;
+
 		/*
 		 * 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");
+		home = utils_get_home_dir();
 		if (home == NULL) {
 			/* Fallback in /tmp .. */
 			home = "/tmp";
@@ -1330,11 +1398,9 @@ static int set_health_socket_path(void)
 /*
  * Check session daemon health for a specific health component.
  *
- * 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.
+ * Return 0 if health is OK or else 1 if BAD.
  *
- * Any other positive value is an lttcomm error which can be translate with
+ * Any other negative value is a lttng error code which can be translated with
  * lttng_strerror().
  */
 int lttng_health_check(enum lttng_health_component c)
@@ -1346,7 +1412,7 @@ int lttng_health_check(enum lttng_health_component c)
 	/* Connect to the sesssion daemon */
 	sock = lttcomm_connect_unix_sock(health_sock_path);
 	if (sock < 0) {
-		ret = -1;
+		ret = -LTTNG_ERR_NO_SESSIOND;
 		goto error;
 	}
 
@@ -1355,20 +1421,129 @@ int lttng_health_check(enum lttng_health_component c)
 
 	ret = lttcomm_send_unix_sock(sock, (void *)&msg, sizeof(msg));
 	if (ret < 0) {
+		ret = -LTTNG_ERR_FATAL;
 		goto close_error;
 	}
 
 	ret = lttcomm_recv_unix_sock(sock, (void *)&reply, sizeof(reply));
 	if (ret < 0) {
+		ret = -LTTNG_ERR_FATAL;
 		goto close_error;
 	}
 
 	ret = reply.ret_code;
 
 close_error:
-	close(sock);
+	{
+		int closeret;
+
+		closeret = close(sock);
+		assert(!closeret);
+	}
+
+error:
+	return ret;
+}
+
+/*
+ * 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;
+	}
+
+	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;
 }
 
@@ -1382,3 +1557,11 @@ static void __attribute__((constructor)) init()
 	/* Set socket for health check */
 	(void) set_health_socket_path();
 }
+
+/*
+ * lib destructor
+ */
+static void __attribute__((destructor)) lttng_ctl_exit()
+{
+	free(tracing_group);
+}