From: Jonathan Rajotte Julien <jonathan.r.julien@gmail.com>
Date: Thu, 12 Jun 2014 19:51:13 +0000 (-0400)
Subject: Mi disable-channel command: support and validation
X-Git-Tag: v2.6.0-rc1~117
X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=50534d6fb4b1f0557b45919c8efad209f68b5e26;p=lttng-tools.git

Mi disable-channel command: support and validation

Signed-off-by: Jonathan Rajotte Julien <jonathan.r.julien@gmail.com>
---

diff --git a/src/bin/lttng/commands/disable_channels.c b/src/bin/lttng/commands/disable_channels.c
index da53d25c9..7ae2ed79a 100644
--- a/src/bin/lttng/commands/disable_channels.c
+++ b/src/bin/lttng/commands/disable_channels.c
@@ -23,6 +23,9 @@
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <unistd.h>
+#include <assert.h>
+
+#include <common/mi-lttng.h>
 
 #include "../command.h"
 
@@ -43,6 +46,7 @@ enum {
 };
 
 static struct lttng_handle *handle;
+static struct mi_writer *writer;
 
 static struct poptOption long_options[] = {
 	/* longName, shortName, argInfo, argPtr, value, descrip, argDesc */
@@ -76,12 +80,57 @@ static void usage(FILE *ofp)
 	fprintf(ofp, "\n");
 }
 
+static int mi_partial_channel_print(char *channel_name, unsigned int enabled,
+		int success)
+{
+	int ret;
+
+	assert(writer);
+	assert(channel_name);
+
+	/* Open channel element */
+	ret = mi_lttng_writer_open_element(writer, config_element_channel);
+	if (ret) {
+		goto end;
+	}
+
+	/* Name */
+	ret = mi_lttng_writer_write_element_string(writer, config_element_name,
+			channel_name);
+	if (ret) {
+		goto end;
+	}
+
+	/* Enabled ? */
+	ret = mi_lttng_writer_write_element_bool(writer, config_element_enabled,
+			enabled);
+	if (ret) {
+		goto end;
+	}
+
+	/* Success ? */
+	ret = mi_lttng_writer_write_element_bool(writer,
+			mi_lttng_element_command, success);
+	if (ret) {
+		goto end;
+	}
+
+	/* Closing channel element */
+	ret = mi_lttng_writer_close_element(writer);
+
+end:
+	return ret;
+}
+
 /*
  * Disabling channel using the lttng API.
  */
 static int disable_channels(char *session_name)
 {
-	int ret = CMD_SUCCESS, warn = 0;
+	int ret = CMD_SUCCESS, warn = 0, success;
+
+	/* Normal case for disable channed is enabled = 0 */
+	unsigned int enabled = 0;
 	char *channel_name;
 	struct lttng_domain dom;
 
@@ -104,6 +153,17 @@ static int disable_channels(char *session_name)
 		goto error;
 	}
 
+	/* Prepare MI */
+	if (lttng_opt_mi) {
+		/* open a channels element */
+		ret = mi_lttng_writer_open_element(writer, config_element_channels);
+		if (ret) {
+			ret = CMD_ERROR;
+			goto error;
+		}
+
+	}
+
 	/* Strip channel list */
 	channel_name = strtok(opt_channels, ",");
 	while (channel_name != NULL) {
@@ -114,9 +174,30 @@ static int disable_channels(char *session_name)
 			ERR("Channel %s: %s (session %s)", channel_name,
 					lttng_strerror(ret), session_name);
 			warn = 1;
+
+			/*
+			 * Mi:
+			 * We assume that if an error occurred the channel is still active.
+			 * This might not be the case but is a good assumption.
+			 * The client should look at the stderr stream for more informations.
+			 */
+			enabled = 1;
+			success = 0;
+
 		} else {
 			MSG("%s channel %s disabled for session %s",
 					get_domain_str(dom.type), channel_name, session_name);
+			enabled = 0;
+			success = 1;
+		}
+
+		/* Print the channel */
+		if (lttng_opt_mi) {
+			ret = mi_partial_channel_print(channel_name, enabled, success);
+			if (ret) {
+				ret = CMD_ERROR;
+				goto error;
+			}
 		}
 
 		/* Next channel */
@@ -125,8 +206,19 @@ static int disable_channels(char *session_name)
 
 	ret = CMD_SUCCESS;
 
+	/* Close Mi */
+	if (lttng_opt_mi) {
+		/* Close channels element */
+		ret = mi_lttng_writer_close_element(writer);
+		if (ret) {
+			ret = CMD_ERROR;
+			goto error;
+		}
+	}
+
 error:
-	if (warn) {
+	/* Bypass the warning if a more important error happened */
+	if (!ret && warn) {
 		ret = CMD_WARNING;
 	}
 
@@ -142,7 +234,7 @@ error:
  */
 int cmd_disable_channels(int argc, const char **argv)
 {
-	int opt, ret = CMD_SUCCESS;
+	int opt, ret = CMD_SUCCESS, command_ret = CMD_SUCCESS, success = 1;
 	static poptContext pc;
 	char *session_name = NULL;
 
@@ -167,13 +259,6 @@ int cmd_disable_channels(int argc, const char **argv)
 		}
 	}
 
-	/* TODO: mi support */
-	if (lttng_opt_mi) {
-		ret = -LTTNG_ERR_MI_NOT_IMPLEMENTED;
-		ERR("mi option not supported");
-		goto end;
-	}
-
 	opt_channels = (char*) poptGetArg(pc);
 	if (opt_channels == NULL) {
 		ERR("Missing channel name(s).\n");
@@ -192,12 +277,75 @@ int cmd_disable_channels(int argc, const char **argv)
 		session_name = opt_session_name;
 	}
 
-	ret = disable_channels(session_name);
+	/* Mi check */
+	if (lttng_opt_mi) {
+		writer = mi_lttng_writer_create(fileno(stdout), lttng_opt_mi);
+		if (!writer) {
+			ret = -LTTNG_ERR_NOMEM;
+			goto end;
+		}
+
+		/* Open command element */
+		ret = mi_lttng_writer_command_open(writer,
+				mi_lttng_element_command_disable_channel);
+		if (ret) {
+			ret = CMD_ERROR;
+			goto end;
+		}
+
+		/* Open output element */
+		ret = mi_lttng_writer_open_element(writer,
+				mi_lttng_element_command_output);
+		if (ret) {
+			ret = CMD_ERROR;
+			goto end;
+		}
+	}
+
+	command_ret = disable_channels(session_name);
+	if (command_ret) {
+		success = 0;
+	}
+
+	/* Mi closing */
+	if (lttng_opt_mi) {
+		/* Close  output element */
+		ret = mi_lttng_writer_close_element(writer);
+		if (ret) {
+			ret = CMD_ERROR;
+			goto end;
+		}
+
+		/* Success ? */
+		ret = mi_lttng_writer_write_element_bool(writer,
+				mi_lttng_element_success, success);
+		if (ret) {
+			ret = CMD_ERROR;
+			goto end;
+		}
+
+		/* Command element close */
+		ret = mi_lttng_writer_command_close(writer);
+		if (ret) {
+			ret = CMD_ERROR;
+			goto end;
+		}
+	}
 
 end:
+	/* Mi clean-up */
+	if (writer && mi_lttng_writer_destroy(writer)) {
+		/* Preserve original error code */
+		ret = ret ? ret : LTTNG_ERR_MI_IO_FAIL;
+	}
+
 	if (!opt_session_name && session_name) {
 		free(session_name);
 	}
+
+	/* Overwrite ret if an error occurred in disable_channels */
+	ret = command_ret ? command_ret : ret;
+
 	poptFreeContext(pc);
 	return ret;
 }
diff --git a/src/bin/lttng/commands/snapshot.c b/src/bin/lttng/commands/snapshot.c
index 564651e09..ebe1d14aa 100644
--- a/src/bin/lttng/commands/snapshot.c
+++ b/src/bin/lttng/commands/snapshot.c
@@ -25,8 +25,10 @@
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <unistd.h>
+#include <assert.h>
 
 #include <common/utils.h>
+#include <common/mi-lttng.h>
 #include <lttng/snapshot.h>
 
 #include "../command.h"
@@ -53,6 +55,8 @@ enum {
 	OPT_LIST_COMMANDS,
 };
 
+static struct mi_writer *writer;
+
 static struct poptOption snapshot_opts[] = {
 	/* longName, shortName, argInfo, argPtr, value, descrip, argDesc */
 	{"help",      'h', POPT_ARG_NONE, 0, OPT_HELP, 0, 0},
@@ -181,6 +185,52 @@ error_create:
 	return NULL;
 }
 
+static int mi_list_output(void)
+{
+	int ret;
+	struct lttng_snapshot_output *s_iter;
+	struct lttng_snapshot_output_list *list;
+
+	assert(writer);
+
+	ret = lttng_snapshot_list_output(current_session_name, &list);
+	if (ret < 0) {
+		goto error;
+	}
+
+	ret = mi_lttng_snapshot_output_session_name(writer, current_session_name);
+	if (ret) {
+		ret = CMD_ERROR;
+		goto end;
+	}
+
+	while ((s_iter = lttng_snapshot_output_list_get_next(list)) != NULL) {
+		ret = mi_lttng_snapshot_list_output(writer, s_iter);
+		if (ret) {
+			ret = CMD_ERROR;
+			goto end;
+		}
+	}
+
+
+	/* Close snapshot snapshots element */
+	ret = mi_lttng_writer_close_element(writer);
+	if (ret) {
+		ret = CMD_ERROR;
+		goto end;
+	}
+
+	/* Close snapshot session element */
+	ret = mi_lttng_writer_close_element(writer);
+	if (ret) {
+		ret = CMD_ERROR;
+	}
+end:
+	lttng_snapshot_output_list_destroy(list);
+error:
+	return ret;
+}
+
 static int list_output(void)
 {
 	int ret, output_seen = 0;
@@ -213,6 +263,51 @@ error:
 	return ret;
 }
 
+/*
+ * Delete output by ID (machine interface version).
+ */
+static int mi_del_output(uint32_t id, const char *name)
+{
+	int ret;
+	struct lttng_snapshot_output *output = NULL;
+
+	assert(writer);
+
+	output = lttng_snapshot_output_create();
+	if (!output) {
+		ret = CMD_FATAL;
+		goto error;
+	}
+
+	if (name) {
+		ret = lttng_snapshot_output_set_name(name, output);
+	} else if (id != UINT32_MAX) {
+		ret = lttng_snapshot_output_set_id(id, output);
+	} else {
+		ret = CMD_ERROR;
+		goto error;
+	}
+	if (ret < 0) {
+		ret = CMD_FATAL;
+		goto error;
+	}
+
+	ret = lttng_snapshot_del_output(current_session_name, output);
+	if (ret < 0) {
+		ret = CMD_FATAL;
+		goto error;
+	}
+
+	ret = mi_lttng_snapshot_del_output(writer, id, name, current_session_name);
+	if (ret) {
+		ret = CMD_ERROR;
+	}
+
+error:
+	lttng_snapshot_output_destroy(output);
+	return ret;
+}
+
 /*
  * Delete output by ID.
  */
@@ -258,6 +353,56 @@ error:
 	return ret;
 }
 
+/*
+ * Add output from the user URL (machine interface).
+ */
+static int mi_add_output(const char *url)
+{
+	int ret;
+	struct lttng_snapshot_output *output = NULL;
+	char name[NAME_MAX];
+	const char *n_ptr;
+
+	if (!url && (!opt_data_url || !opt_ctrl_url)) {
+		ret = CMD_ERROR;
+		goto error;
+	}
+
+	output = create_output_from_args(url);
+	if (!output) {
+		ret = CMD_FATAL;
+		goto error;
+	}
+
+	/* This call, if successful, populates the id of the output object. */
+	ret = lttng_snapshot_add_output(current_session_name, output);
+	if (ret < 0) {
+		ret = CMD_ERROR;
+		goto error;
+	}
+
+	n_ptr = lttng_snapshot_output_get_name(output);
+	if (*n_ptr == '\0') {
+		int pret;
+		pret = snprintf(name, sizeof(name), DEFAULT_SNAPSHOT_NAME "-%" PRIu32,
+				lttng_snapshot_output_get_id(output));
+		if (pret < 0) {
+			PERROR("snprintf add output name");
+		}
+		n_ptr = name;
+	}
+
+	ret = mi_lttng_snapshot_add_output(writer, current_session_name, n_ptr,
+			output);
+	if (ret) {
+		ret = CMD_ERROR;
+	}
+
+error:
+	lttng_snapshot_output_destroy(output);
+	return ret;
+}
+
 /*
  * Add output from the user URL.
  */
@@ -309,7 +454,7 @@ error:
 
 static int cmd_add_output(int argc, const char **argv)
 {
-	int ret = CMD_SUCCESS;
+	int ret;
 
 	if (argc < 2 && (!opt_data_url || !opt_ctrl_url)) {
 		usage(stderr);
@@ -317,7 +462,11 @@ static int cmd_add_output(int argc, const char **argv)
 		goto end;
 	}
 
-	ret = add_output(argv[1]);
+	if (lttng_opt_mi) {
+		ret = mi_add_output(argv[1]);
+	} else {
+		ret = add_output(argv[1]);
+	}
 
 end:
 	return ret;
@@ -325,7 +474,7 @@ end:
 
 static int cmd_del_output(int argc, const char **argv)
 {
-	int ret = CMD_SUCCESS;
+	int ret;
 	char *name;
 	long id;
 
@@ -338,9 +487,17 @@ static int cmd_del_output(int argc, const char **argv)
 	errno = 0;
 	id = strtol(argv[1], &name, 10);
 	if (id == 0 && errno == 0) {
-		ret = del_output(UINT32_MAX, name);
+		if (lttng_opt_mi) {
+			ret = mi_del_output(UINT32_MAX, name);
+		} else {
+			ret = del_output(UINT32_MAX, name);
+		}
 	} else if (errno == 0 && *name == '\0') {
-		ret = del_output(id, NULL);
+		if (lttng_opt_mi) {
+			ret = mi_del_output(id, NULL);
+		} else {
+			ret = del_output(id, NULL);
+		}
 	} else {
 		ERR("Argument %s not recognized", argv[1]);
 		ret = -1;
@@ -353,7 +510,46 @@ end:
 
 static int cmd_list_output(int argc, const char **argv)
 {
-	return list_output();
+	int ret;
+
+	if (lttng_opt_mi) {
+		ret = mi_list_output();
+	} else {
+		ret = list_output();
+	}
+
+	return ret;
+}
+
+/*
+ * Do a snapshot record with the URL if one is given (machine interface).
+ */
+static int mi_record(const char *url)
+{
+	int ret;
+	struct lttng_snapshot_output *output = NULL;
+
+	output = create_output_from_args(url);
+	if (!output) {
+		ret = CMD_FATAL;
+		goto error;
+	}
+
+	ret = lttng_snapshot_record(current_session_name, output, 0);
+	if (ret < 0) {
+		ret = CMD_ERROR;
+		goto error;
+	}
+
+	ret = mi_lttng_snapshot_record(writer, current_session_name, url,
+			opt_ctrl_url, opt_data_url);
+	if (ret) {
+		ret = CMD_ERROR;
+	}
+
+error:
+	lttng_snapshot_output_destroy(output);
+	return ret;
 }
 
 /*
@@ -400,9 +596,17 @@ static int cmd_record(int argc, const char **argv)
 
 	if (argc == 2) {
 		/* With a given URL */
-		ret = record(argv[1]);
+		if (lttng_opt_mi) {
+			ret = mi_record(argv[1]);
+		} else {
+			ret = record(argv[1]);
+		}
 	} else {
-		ret = record(NULL);
+		if (lttng_opt_mi) {
+			ret = mi_record(NULL);
+		} else {
+			ret = record(NULL);
+		}
 	}
 
 	return ret;
@@ -410,13 +614,13 @@ static int cmd_record(int argc, const char **argv)
 
 static int handle_command(const char **argv)
 {
-	int ret, i = 0, argc;
+	int ret = CMD_SUCCESS, i = 0, argc, command_ret =  CMD_SUCCESS;
 	struct cmd_struct *cmd;
 
 	if (argv == NULL || (!opt_ctrl_url && opt_data_url) ||
 			(opt_ctrl_url && !opt_data_url)) {
 		usage(stderr);
-		ret = CMD_ERROR;
+		command_ret = CMD_ERROR;
 		goto end;
 	}
 
@@ -426,37 +630,90 @@ static int handle_command(const char **argv)
 	while (cmd->func != NULL) {
 		/* Find command */
 		if (strcmp(argv[0], cmd->name) == 0) {
-			ret = cmd->func(argc, argv);
+			if (lttng_opt_mi) {
+				/* Action element */
+				ret = mi_lttng_writer_open_element(writer,
+						mi_lttng_element_command_action);
+				if (ret) {
+					ret = CMD_ERROR;
+					goto end;
+				}
+
+				/* Name of the action */
+				ret = mi_lttng_writer_write_element_string(writer,
+						config_element_name, argv[0]);
+				if (ret) {
+					ret = CMD_ERROR;
+					goto end;
+				}
+
+				/* Open output element */
+				ret = mi_lttng_writer_open_element(writer,
+						mi_lttng_element_command_output);
+				if (ret) {
+					ret = CMD_ERROR;
+					goto end;
+				}
+			}
+
+			command_ret = cmd->func(argc, argv);
+
+			if (lttng_opt_mi) {
+				/* Close output and action element */
+				ret = mi_lttng_close_multi_element(writer, 2);
+				if (ret) {
+					ret = CMD_ERROR;
+					goto end;
+				}
+			}
 			goto end;
 		}
 		i++;
 		cmd = &actions[i];
 	}
 
-	/* Command not found */
-	ret = CMD_UNDEFINED;
+	ret = -CMD_UNDEFINED;
 
 end:
+	/* Overwrite ret if an error occured in cmd->func() */
+	ret = command_ret ? command_ret : ret;
 	return ret;
 }
-
 /*
  * The 'snapshot <cmd> <options>' first level command
  */
 int cmd_snapshot(int argc, const char **argv)
 {
-	int opt, ret = CMD_SUCCESS;
+	int opt, ret = CMD_SUCCESS, command_ret = CMD_SUCCESS, success = 1;
 	char *session_name = NULL;
 	static poptContext pc;
 
 	pc = poptGetContext(NULL, argc, argv, snapshot_opts, 0);
 	poptReadDefaultConfig(pc, 0);
 
-	/* TODO: mi support */
+	/* Mi check */
 	if (lttng_opt_mi) {
-		ret = -LTTNG_ERR_MI_NOT_IMPLEMENTED;
-		ERR("mi option not supported");
-		goto end;
+		writer = mi_lttng_writer_create(fileno(stdout), lttng_opt_mi);
+		if (!writer) {
+			ret = -LTTNG_ERR_NOMEM;
+			goto end;
+		}
+
+		/* Open command element */
+		ret = mi_lttng_writer_command_open(writer,
+				mi_lttng_element_command_snapshot);
+		if (ret) {
+			ret = CMD_ERROR;
+			goto end;
+		}
+
+		/* Open output element */
+		ret = mi_lttng_writer_open_element(writer,
+				mi_lttng_element_command_output);
+		if (ret) {
+			ret = CMD_ERROR;
+			goto end;
+		}
 	}
 
 	while ((opt = poptGetNextOpt(pc)) != -1) {
@@ -503,26 +760,59 @@ int cmd_snapshot(int argc, const char **argv)
 		current_session_name = opt_session_name;
 	}
 
-	ret = handle_command(poptGetArgs(pc));
-	if (ret < 0) {
-		switch (-ret) {
+	command_ret = handle_command(poptGetArgs(pc));
+	if (command_ret < 0) {
+		switch (-command_ret) {
 		case LTTNG_ERR_EPERM:
 			ERR("The session needs to be set in no output mode (--no-output)");
 			break;
 		case LTTNG_ERR_SNAPSHOT_NODATA:
-			WARN("%s", lttng_strerror(ret));
+			WARN("%s", lttng_strerror(command_ret));
 			break;
 		default:
-			ERR("%s", lttng_strerror(ret));
+			ERR("%s", lttng_strerror(command_ret));
 			break;
 		}
-		goto end;
+		success = 0;
+	}
+
+	if (lttng_opt_mi) {
+		/* Close output element */
+		ret = mi_lttng_writer_close_element(writer);
+		if (ret) {
+			ret = CMD_ERROR;
+			goto end;
+		}
+
+		/* Success ? */
+		ret = mi_lttng_writer_write_element_bool(writer,
+				mi_lttng_element_command_success, success);
+		if (ret) {
+			ret = CMD_ERROR;
+			goto end;
+		}
+
+		/* Command element close */
+		ret = mi_lttng_writer_command_close(writer);
+		if (ret) {
+			ret = CMD_ERROR;
+			goto end;
+		}
 	}
 
 end:
+	/* Mi clean-up */
+	if (writer && mi_lttng_writer_destroy(writer)) {
+		/* Preserve original error code */
+		ret = ret ? ret : -LTTNG_ERR_MI_IO_FAIL;
+	}
+
 	if (!opt_session_name) {
 		free(session_name);
 	}
+
+	/* Overwrite ret if an error occured during handle_command */
+	ret = command_ret ? command_ret : ret;
 	poptFreeContext(pc);
 	return ret;
 }
diff --git a/src/common/mi-lttng.c b/src/common/mi-lttng.c
index 7d5e9c6f9..1b65ddd4c 100644
--- a/src/common/mi-lttng.c
+++ b/src/common/mi-lttng.c
@@ -19,6 +19,7 @@
 
 #include <include/config.h>
 #include <common/config/config.h>
+#include <lttng/snapshot-internal.h>
 #include "mi-lttng.h"
 
 #include <assert.h>
@@ -40,6 +41,8 @@ const char * const mi_lttng_element_command_add_context = "add-context";
 const char * const mi_lttng_element_command_enable_channels = "enable-channel";
 const char * const mi_lttng_element_command_set_session = "set-session";
 const char * const mi_lttng_element_command_disable_event = "disable-event";
+const char * const mi_lttng_element_command_disable_channel = "disable-channel";
+const char * const mi_lttng_element_command_action = "snapshot_action";
 const char * const mi_lttng_element_command_output = "output";
 const char * const mi_lttng_element_command_success = "success";
 
@@ -53,11 +56,15 @@ const char * const mi_lttng_element_version_commit = "commit";
 const char * const mi_lttng_element_version_license = "license";
 const char * const mi_lttng_element_version_patch_level = "patchLevel";
 const char * const mi_lttng_element_version_description = "description";
+const char * const mi_lttng_element_command_snapshot = "snapshot";
+const char * const mi_lttng_element_command_list_snapshot = "list_snapshot";
+const char * const mi_lttng_element_command_del_snapshot = "del_snapshot";
+const char * const mi_lttng_element_command_add_snapshot = "add_snapshot";
+const char * const mi_lttng_element_command_record_snapshot = "record_snapshot";
 
 /* Strings related to pid */
 const char * const mi_lttng_element_pids = "pids";
 const char * const mi_lttng_element_pid = "pid";
-const char * const mi_lttng_element_pid_id = "id";
 
 /* Strings related to save command */
 const char * const mi_lttng_element_save = "save";
@@ -85,6 +92,8 @@ const char * const mi_lttng_element_type_float = "FLOAT";
 const char * const mi_lttng_element_type_string = "STRING";
 const char * const mi_lttng_element_nowrite = "nowrite";
 const char * const mi_lttng_element_success = "success";
+const char * const mi_lttng_element_id = "id";
+const char * const mi_lttng_element_empty = "";
 
 /* String related to loglevel */
 const char * const mi_lttng_loglevel_str_alert = "TRACE_ALERT";
@@ -114,7 +123,13 @@ const char * const mi_lttng_loglevel_type_unknown = "UNKNOWN";
 const char * const mi_lttng_element_calibrate = "calibrate";
 const char * const mi_lttng_element_calibrate_function = "FUNCTION";
 
-const char * const mi_lttng_element_empty = "";
+/* String related to a lttng_snapshot_output */
+const char * const mi_lttng_element_snapshots = "snapshots";
+const char * const mi_lttng_element_snapshot_session_name = "session_name";
+const char * const mi_lttng_element_snapshot_n_ptr = "n_ptr";
+const char * const mi_lttng_element_snapshot_data_url = "data_url";
+const char * const mi_lttng_element_snapshot_ctrl_url = "ctrl_url";
+const char * const mi_lttng_element_snapshot_max_size = "max_size";
 
 const char *mi_lttng_loglevel_string(int value)
 {
@@ -1151,3 +1166,238 @@ int mi_lttng_perf_counter_context(struct mi_writer *writer,
 end:
 	return ret;
 }
+
+LTTNG_HIDDEN
+int mi_lttng_snapshot_output_session_name(struct mi_writer *writer,
+		const char *session_name)
+{
+	int ret;
+
+	/* Open session element */
+	ret = mi_lttng_writer_open_element(writer, config_element_session);
+	if (ret) {
+		goto end;
+	}
+
+	/* Snapshot output list for current session name */
+	ret = mi_lttng_writer_write_element_string(writer, config_element_name,
+			session_name);
+
+	/* Open element snapshots (sequence one snapshot) */
+	ret = mi_lttng_writer_open_element(writer, mi_lttng_element_snapshots);
+	if (ret) {
+		goto end;
+	}
+
+end:
+	return ret;
+}
+
+LTTNG_HIDDEN
+int mi_lttng_snapshot_list_output(struct mi_writer *writer,
+		struct lttng_snapshot_output *output)
+{
+	int ret;
+
+	/* Open element snapshot output */
+	ret = mi_lttng_writer_open_element(writer,
+			mi_lttng_element_command_snapshot);
+	if (ret) {
+		goto end;
+	}
+
+	/* ID of the snapshot output */
+	ret = mi_lttng_writer_write_element_unsigned_int(writer,
+			mi_lttng_element_id, output->id);
+	if (ret) {
+		goto end;
+	}
+
+	/* Name of the output */
+	ret = mi_lttng_writer_write_element_string(writer, config_element_name,
+			output->name);
+	if (ret) {
+		goto end;
+	}
+
+	/* Destination of the output (ctrl_url)*/
+	ret = mi_lttng_writer_write_element_string(writer,
+			mi_lttng_element_snapshot_ctrl_url, output->ctrl_url);
+	if (ret) {
+		goto end;
+	}
+
+	/* Destination of the output (data_url) */
+	ret = mi_lttng_writer_write_element_string(writer,
+			mi_lttng_element_snapshot_data_url, output->data_url);
+	if (ret) {
+		goto end;
+	}
+
+	/* total size of all stream combined */
+	ret = mi_lttng_writer_write_element_unsigned_int(writer,
+			mi_lttng_element_snapshot_max_size, output->max_size);
+	if (ret) {
+		goto end;
+	}
+
+	/* Close snapshot output element */
+	ret = mi_lttng_writer_close_element(writer);
+
+end:
+	return ret;
+}
+
+LTTNG_HIDDEN
+int mi_lttng_snapshot_del_output(struct mi_writer *writer, int id,
+		const char *name, const char *current_session_name)
+{
+	int ret;
+
+	/* Open element del_snapshot */
+	ret = mi_lttng_writer_open_element(writer,
+			mi_lttng_element_command_snapshot);
+	if (ret) {
+		goto end;
+	}
+
+
+	if (id != UINT32_MAX) {
+		/* "Snapshot output "id" successfully deleted
+		 * for "current_session_name"
+		 * ID of the snapshot output
+		 */
+		ret = mi_lttng_writer_write_element_unsigned_int(writer,
+				mi_lttng_element_id, id);
+		if (ret) {
+			goto end;
+		}
+	} else {
+		/* "Snapshot output "name" successfully deleted
+		 * for session "current_session_name"
+		 * Name of the output
+		 */
+		ret = mi_lttng_writer_write_element_string(writer, config_element_name,
+				name);
+		if (ret) {
+			goto end;
+		}
+	}
+
+	/* Snapshot was deleted for session "current_session_name"*/
+	ret = mi_lttng_writer_write_element_string(writer,
+			mi_lttng_element_snapshot_session_name,
+			current_session_name);
+	if (ret) {
+		goto end;
+	}
+
+	/* Close snapshot element */
+	ret = mi_lttng_writer_close_element(writer);
+
+end:
+	return ret;
+}
+
+LTTNG_HIDDEN
+int mi_lttng_snapshot_add_output(struct mi_writer *writer,
+		const char *current_session_name, const char *n_ptr,
+		struct lttng_snapshot_output *output)
+{
+	int ret;
+
+	/* Open element snapshot */
+	ret = mi_lttng_writer_open_element(writer,
+			mi_lttng_element_command_snapshot);
+	if (ret) {
+		goto end;
+	}
+
+	/* Snapshot output id */
+	ret = mi_lttng_writer_write_element_unsigned_int(writer,
+			mi_lttng_element_id, output->id);
+	if (ret) {
+		goto end;
+	}
+
+	/* Snapshot output names */
+	ret = mi_lttng_writer_write_element_string(writer,
+			config_element_name, n_ptr);
+	if (ret) {
+		goto end;
+	}
+
+	/* Destination of the output (ctrl_url)*/
+	ret = mi_lttng_writer_write_element_string(writer,
+			mi_lttng_element_snapshot_ctrl_url, output->ctrl_url);
+	if (ret) {
+		goto end;
+	}
+
+	/* Snapshot added for session "current_session_name"*/
+	ret = mi_lttng_writer_write_element_string(writer,
+			mi_lttng_element_snapshot_session_name, current_session_name);
+	if (ret) {
+		goto end;
+	}
+
+	/* total size of all stream combined */
+	ret = mi_lttng_writer_write_element_unsigned_int(writer,
+			mi_lttng_element_snapshot_max_size, output->max_size);
+	if (ret) {
+		goto end;
+	}
+
+	/* Close snapshot element */
+	ret = mi_lttng_writer_close_element(writer);
+
+end:
+	return ret;
+}
+
+LTTNG_HIDDEN
+int mi_lttng_snapshot_record(struct mi_writer *writer,
+		const char *current_session_name, const char *url,
+		const char *cmdline_ctrl_url, const char *cmdline_data_url)
+{
+	int ret;
+
+	/* Open element snapshot */
+	ret = mi_lttng_writer_open_element(writer,
+			mi_lttng_element_command_snapshot);
+	if (ret) {
+		goto end;
+	}
+
+	/*
+	 * If a valid an URL was given, serialize it,
+	 * else take the command line data and ctrl urls*/
+	if (url) {
+		/* Destination of the output (ctrl_url)*/
+		ret = mi_lttng_writer_write_element_string(writer,
+				mi_lttng_element_snapshot_ctrl_url, url);
+		if (ret) {
+			goto end;
+		}
+	} else if (cmdline_ctrl_url) {
+		/* Destination of the output (ctrl_url)*/
+		ret = mi_lttng_writer_write_element_string(writer,
+				mi_lttng_element_snapshot_ctrl_url, cmdline_ctrl_url);
+		if (ret) {
+			goto end;
+		}
+
+		/* Destination of the output (data_url) */
+		ret = mi_lttng_writer_write_element_string(writer,
+				mi_lttng_element_snapshot_data_url, cmdline_data_url);
+		if (ret) {
+			goto end;
+		}
+	}
+
+	/* Close record_snapshot element */
+	ret = mi_lttng_writer_close_element(writer);
+
+end:
+	return ret;
+}
diff --git a/src/common/mi-lttng.h b/src/common/mi-lttng.h
index 9d7edaf44..6215df567 100644
--- a/src/common/mi-lttng.h
+++ b/src/common/mi-lttng.h
@@ -26,6 +26,9 @@
 #include <common/config/config.h>
 #include <lttng/lttng.h>
 
+/* Don't want to reference snapshot-internal.h here */
+struct lttng_snapshot_output;
+
 /* Instance of a machine interface writer. */
 struct mi_writer {
 	struct config_writer *writer;
@@ -48,6 +51,7 @@ struct mi_lttng_version {
 /* Strings related to command */
 const char * const mi_lttng_element_command;
 const char * const mi_lttng_element_command_name;
+const char * const mi_lttng_element_command_action;
 const char * const mi_lttng_element_command_version;
 const char * const mi_lttng_element_command_enable_event;
 const char * const mi_lttng_element_command_list;
@@ -62,6 +66,12 @@ const char * const mi_lttng_element_command_add_context;
 const char * const mi_lttng_element_command_enable_channels;
 const char * const mi_lttng_element_command_set_session;
 const char * const mi_lttng_element_command_disable_event;
+const char * const mi_lttng_element_command_disable_channel;
+const char * const mi_lttng_element_command_snapshot;
+const char * const mi_lttng_element_command_list_snapshot;
+const char * const mi_lttng_element_command_del_snapshot;
+const char * const mi_lttng_element_command_add_snapshot;
+const char * const mi_lttng_element_command_record_snapshot;
 const char * const mi_lttng_element_command_output;
 const char * const mi_lttng_element_command_success;
 
@@ -136,6 +146,14 @@ const char * const mi_lttng_loglevel_type_unknown;
 const char * const mi_lttng_element_calibrate;
 const char * const mi_lttng_element_calibrate_function;
 
+/* String related to a lttng_snashot */
+const char * const mi_lttng_element_snapshots;
+const char * const mi_lttng_element_snapshot_session_name;
+const char * const mi_lttng_element_snapshot_n_ptr;
+const char * const mi_lttng_element_snapshot_data_url;
+const char * const mi_lttng_element_snapshot_ctrl_url;
+const char * const mi_lttng_element_snapshot_max_size;
+
 /* Utility string function  */
 const char *mi_lttng_loglevel_string(int value);
 const char *mi_lttng_logleveltype_string(enum lttng_loglevel_type value);
@@ -553,8 +571,6 @@ int mi_lttng_calibrate(struct mi_writer *writer,
  * is_open Define if we close the context element
  *         This should be used carefully and the client
  *         need to close the context element.
- *         0-> False
- *         1-> True
  * Returns zero if the element's value could be written.
  * Negative values indicate an error.
  */
@@ -574,4 +590,117 @@ int mi_lttng_context(struct mi_writer *writer,
 int mi_lttng_perf_counter_context(struct mi_writer *writer,
 		struct lttng_event_perf_counter_ctx  *perf_context);
 
+/*
+ * Machine interface of the snapshot list_output.
+ * It specifies the session for which we are listing snapshots,
+ * and it opens a snapshots element to list a sequence
+ * of snapshots.
+ *
+ * writer An instance of a machine interface writer.
+ *
+ * session_name: Snapshot output for session "session_name".
+ *
+ * Note: The client has to close the session and the snapshots elements after
+ * having listed every lttng_snapshot_output.
+ *
+ * Returns zero if the element's value could be written.
+ * Negative values indicate an error.
+ */
+int mi_lttng_snapshot_output_session_name(struct mi_writer *writer,
+		const char *session_name);
+
+/*
+ * Machine interface of the snapshot output.
+ * The machine interface serializes the following attributes:
+ * - id: ID of the snapshot output.
+ * - name: Name of the output.
+ * - data_url : Destination of the output.
+ * - ctrl_url: Destination of the output.
+ * - max_size: total size of all stream combined.
+ *
+ * writer An instance of a machine interface writer.
+ *
+ * output: A list of snapshot_output.
+ *
+ * Returns zero if the element's value could be written.
+ * Negative values indicate an error.
+ */
+int mi_lttng_snapshot_list_output(struct mi_writer *writer,
+		struct lttng_snapshot_output *output);
+
+/*
+ * Machine interface of the output of the command snapshot del output
+ * when deleting a snapshot either by id or by name.
+ * If the snapshot was found and successfully deleted using its id,
+ * it return the id of the snapshot and the current session name on which it
+ * was attached.
+ *
+ * Otherwise, it do the same process with the name of the snapshot, if the
+ * snapshot output id is undefined.
+ *
+ * writer An instance of a machine interface writer.
+ *
+ * id: ID of the snapshot output.
+ *
+ * name: Name of the snapshot.
+ *
+ * current_session_name: Session to which the snapshot belongs.
+ *
+ * Returns zero if the element's value could be written.
+ * Negative values indicate an error.
+ */
+int mi_lttng_snapshot_del_output(struct mi_writer *writer, int id,
+		const char *name, const char *current_session_name);
+
+/*
+ * Machine interface of the output of the command snapshot add output
+ * when adding a snapshot from a user URL.
+ *
+ * If the snapshot was successfully added, the machine interface lists
+ * these information:
+ * - id: ID of the newly add snapshot output.
+ * - current_session_name: Name of the session to which the output was added.
+ * - ctrl_url: Destination of the output.
+ * - max_size: total size of all stream combined.
+ *
+ * writer An instance of a machine interface writer.
+ *
+ * current_session_name: Session to which the snapshot belongs.
+ *
+ * n_ptr:
+ *
+ * output: iterator over a lttng_snapshot_output_list which contain
+ * the snapshot output informations.
+ *
+ * Returns zero if the element's value could be written.
+ * Negative values indicate an error.
+ */
+int mi_lttng_snapshot_add_output(struct mi_writer *writer,
+		const char *current_session_name, const char *n_ptr,
+		struct lttng_snapshot_output *output);
+
+/*
+ * Machine interface of the output of the command snapshot
+ * record  from a URL (if given).
+ *
+ * If the snapshot is successfully recorded from a url, the machine interface
+ * output the following information:
+ * - url: Destination of the output stored in the snapshot.
+ *
+ * Otherwise, the machine interface output the data and ctrl url received
+ * from the command-line.
+ *
+ * writer An instance of a machine interface writer.
+ *
+ * current_session_name: Snapshot record for session "current_session_name".
+ *
+ * ctrl_url, data_url: Destination of the output receive from the command-line.
+ *
+ * Returns zero if the element's value could be written.
+ * Negative values indicate an error.
+ */
+int mi_lttng_snapshot_record(struct mi_writer *writer,
+		const char *current_session_name, const char *url,
+		const char *cmdline_ctrl_url, const char *cmdline_data_url);
+
 #endif /* _MI_LTTNG_H */
diff --git a/src/common/mi_lttng.xsd b/src/common/mi_lttng.xsd
index 4535040bc..2b28a314b 100644
--- a/src/common/mi_lttng.xsd
+++ b/src/common/mi_lttng.xsd
@@ -285,6 +285,24 @@ THE SOFTWARE.
 		</xs:all>
 	</xs:complexType>
 
+	<!-- Maps to struct lttng_snapshot_output -->
+	<xs:complexType name="snapshot_type">
+		<xs:all>
+			<xs:element name="id" type="uint32_type" minOccurs="0" />
+			<xs:element name="max_size" type="uint64_type" minOccurs="0" />
+			<xs:element name="name" type="name_type" minOccurs="0" />
+			<xs:element name="session_name" type="name_type" minOccurs="0" />
+			<xs:element name="ctrl_url" type="name_type" minOccurs="0"/>
+			<xs:element name="data_url" type="name_type" minOccurs="0"/>
+		</xs:all>
+	</xs:complexType>
+
+	<xs:complexType name="snapshots_type">
+		<xs:sequence>
+			<xs:element name="snapshot" type="snapshot_type" minOccurs="0" maxOccurs="unbounded" />
+		</xs:sequence>
+	</xs:complexType>
+
 	<xs:complexType name="channels_type">
 		<xs:sequence>
 			<xs:element name="channel" type="channel_type" minOccurs="0" maxOccurs="unbounded" />
@@ -300,6 +318,7 @@ THE SOFTWARE.
 			<xs:element name="live_timer_interval" type="uint32_type" minOccurs="0" />
 			<xs:element name="channels" type="channels_type" minOccurs="0" />
 			<xs:element name="domains" type="domains_type" minOccurs="0" />
+			<xs:element name="snapshots" type="snapshots_type" minOccurs="0" />
 		</xs:all>
 	</xs:complexType>
 
@@ -377,11 +396,30 @@ THE SOFTWARE.
 		</xs:sequence>
 	</xs:complexType>
 
+	<xs:complexType name="snapshot_action_type">
+		<xs:sequence>
+			<xs:element name="name" type="snapshot_actiontype_type" minOccurs="0" />
+			<xs:element name="output" type="output_type" minOccurs="0" />
+		</xs:sequence>
+	</xs:complexType>
+
+	<!-- Type of snapshot commands -->
+	<xs:simpleType name="snapshot_actiontype_type">
+		<xs:restriction base="xs:string">
+			<xs:enumeration value="list-output"/>
+			<xs:enumeration value="del-output"/>
+			<xs:enumeration value="add-output"/>
+			<xs:enumeration value="record-output"/>
+		</xs:restriction>
+	</xs:simpleType>
+
 	<xs:complexType name="output_type">
 		<xs:choice>
 			<xs:element name="domains" type="domains_type" minOccurs="0" />
+			<xs:element name="session" type="session_type" minOccurs="0" />
 			<xs:element name="sessions" type="sessions_type" minOccurs="0" />
 			<xs:element name="session" type="session_type" minOccurs="0" />
+			<xs:element name="snapshot_action" type="snapshot_action_type" minOccurs="0" />
 			<xs:element name="version" type="version_type" minOccurs="0" />
 			<xs:element name="save" type="save_type" minOccurs="0" />
 			<xs:element name="load" type="load_type" minOccurs="0" />
@@ -390,6 +428,7 @@ THE SOFTWARE.
 			<xs:element name="channels" type="channels_type" minOccurs="0" />
 			<xs:element name="events" type="event_list_type" minOccurs="0" />
 			<xs:element name="channel" type="channel_type" minOccurs="0" />
+			<xs:element name="channels" type="channels_type" minOccurs="0" />
 		</xs:choice>
 	</xs:complexType>
 
@@ -398,6 +437,7 @@ THE SOFTWARE.
 		<xs:restriction base="xs:string">
 			<xs:enumeration value="create" />
 			<xs:enumeration value="list" />
+			<xs:enumeration value="snapshot" />
 			<xs:enumeration value="version" />
 			<xs:enumeration value="save" />
 			<xs:enumeration value="load" />
@@ -410,6 +450,7 @@ THE SOFTWARE.
 			<xs:enumeration value="enable-event" />
 			<xs:enumeration value="set-session" />
 			<xs:enumeration value="disable-event" />
+			<xs:enumeration value="disable-channel" />
 		</xs:restriction>
 	</xs:simpleType>