X-Git-Url: http://git.efficios.com/?p=lttng-tools.git;a=blobdiff_plain;f=src%2Fbin%2Flttng%2Fcommands%2Fadd_trigger.c;fp=src%2Fbin%2Flttng%2Fcommands%2Fadd_trigger.c;h=277a7e338487f9941b68d33810b803a0a22e9a38;hp=0000000000000000000000000000000000000000;hb=2463b7879c00298daa79744cdaae82ac061a4ed8;hpb=3a4595c2469472dee1656cde5f8882c2123efd3c

diff --git a/src/bin/lttng/commands/add_trigger.c b/src/bin/lttng/commands/add_trigger.c
new file mode 100644
index 000000000..277a7e338
--- /dev/null
+++ b/src/bin/lttng/commands/add_trigger.c
@@ -0,0 +1,2161 @@
+#include <stdio.h>
+#include <ctype.h>
+
+#include "../command.h"
+#include "../uprobe.h"
+
+#include "common/argpar/argpar.h"
+#include "common/dynamic-array.h"
+#include "common/string-utils/string-utils.h"
+#include "common/utils.h"
+#include "lttng/condition/event-rule.h"
+#include "lttng/event-internal.h"
+#include "lttng/event-expr.h"
+#include <lttng/event-rule/event-rule-internal.h>
+#include "lttng/event-rule/kprobe.h"
+#include "lttng/event-rule/syscall.h"
+#include <lttng/event-rule/tracepoint.h>
+#include "lttng/event-rule/uprobe.h"
+#include "lttng/kernel-probe.h"
+#include "common/filter/filter-ast.h"
+#include "common/filter/filter-ir.h"
+#include "common/dynamic-array.h"
+
+
+#if (LTTNG_SYMBOL_NAME_LEN == 256)
+#define LTTNG_SYMBOL_NAME_LEN_SCANF_IS_A_BROKEN_API	"255"
+#endif
+
+#ifdef LTTNG_EMBED_HELP
+static const char help_msg[] =
+#include <lttng-add-trigger.1.h>
+;
+#endif
+
+enum {
+	OPT_HELP,
+	OPT_LIST_OPTIONS,
+
+	OPT_CONDITION,
+	OPT_ACTION,
+	OPT_ID,
+	OPT_FIRE_ONCE_AFTER,
+	OPT_FIRE_EVERY,
+	OPT_USER_ID,
+
+	OPT_ALL,
+	OPT_FILTER,
+	OPT_EXCLUDE,
+	OPT_LOGLEVEL,
+	OPT_LOGLEVEL_ONLY,
+
+	OPT_USERSPACE,
+	OPT_KERNEL,
+	OPT_LOG4J,
+	OPT_JUL,
+	OPT_PYTHON,
+
+	OPT_FUNCTION,
+	OPT_PROBE,
+	OPT_USERSPACE_PROBE,
+	OPT_SYSCALL,
+	OPT_TRACEPOINT,
+
+	OPT_NAME,
+	OPT_MAX_SIZE,
+	OPT_DATA_URL,
+	OPT_CTRL_URL,
+
+	OPT_CAPTURE,
+};
+
+static const struct argpar_opt_descr event_rule_opt_descrs[] = {
+	{ OPT_ALL, 'a', "all", false },
+	{ OPT_FILTER, 'f', "filter", true },
+	{ OPT_EXCLUDE, 'x', "exclude", true },
+	{ OPT_LOGLEVEL, '\0', "loglevel", true },
+	{ OPT_LOGLEVEL_ONLY, '\0', "loglevel-only", true },
+
+	/* Domains */
+	{ OPT_USERSPACE, 'u', "userspace", false },
+	{ OPT_KERNEL, 'k', "kernel", false },
+	{ OPT_LOG4J, 'l', "log4j", false },
+	{ OPT_JUL, 'j', "jul", false },
+	{ OPT_PYTHON, 'p', "python", false },
+
+	/* Event rule types */
+	{ OPT_FUNCTION, '\0', "function", true },
+	{ OPT_PROBE, '\0', "probe", true },
+	{ OPT_USERSPACE_PROBE, '\0', "userspace-probe", true },
+	{ OPT_SYSCALL, '\0', "syscall" },
+	{ OPT_TRACEPOINT, '\0', "tracepoint" },
+
+	/* Capture descriptor */
+	{ OPT_CAPTURE, '\0', "capture", true },
+
+	ARGPAR_OPT_DESCR_SENTINEL
+};
+
+static
+bool assign_domain_type(enum lttng_domain_type *dest,
+		enum lttng_domain_type src)
+{
+	bool ret;
+
+	if (*dest == LTTNG_DOMAIN_NONE || *dest == src) {
+		*dest = src;
+		ret = true;
+	} else {
+		ERR("Multiple domains specified.");
+		ret = false;
+	}
+
+	return ret;
+}
+
+static
+bool assign_event_rule_type(enum lttng_event_rule_type *dest,
+		enum lttng_event_rule_type src)
+{
+	bool ret;
+
+	if (*dest == LTTNG_EVENT_RULE_TYPE_UNKNOWN || *dest == src) {
+		*dest = src;
+		ret = true;
+	} else {
+		ERR("Multiple event type not supported.");
+		ret = false;
+	}
+
+	return ret;
+}
+
+static
+bool assign_string(char **dest, const char *src, const char *opt_name)
+{
+	bool ret;
+
+	if (*dest) {
+		ERR(
+			"Duplicate %s given.", opt_name);
+		goto error;
+	}
+
+	*dest = strdup(src);
+	if (!*dest) {
+		ERR("Failed to allocate %s string.", opt_name);
+		goto error;
+	}
+
+	ret = true;
+	goto end;
+
+error:
+	ret = false;
+
+end:
+	return ret;
+}
+
+/* This is defined in enable_events.c. */
+LTTNG_HIDDEN
+int create_exclusion_list_and_validate(const char *event_name,
+		const char *exclusions_arg,
+		char ***exclusion_list);
+
+/*
+ * Parse `str` as a log level in domain `domain_type`.  Return -1 if the string
+ * is not recognized as a valid log level.
+ */
+static
+int parse_loglevel_string(const char *str, enum lttng_domain_type domain_type)
+{
+
+	switch (domain_type) {
+	case LTTNG_DOMAIN_UST:
+		return loglevel_str_to_value(str);
+
+	case LTTNG_DOMAIN_LOG4J:
+		return loglevel_log4j_str_to_value(str);
+
+	case LTTNG_DOMAIN_JUL:
+		return loglevel_jul_str_to_value(str);
+
+	case LTTNG_DOMAIN_PYTHON:
+		return loglevel_python_str_to_value(str);
+
+	default:
+		/* Invalid domain type. */
+		abort();
+	}
+}
+
+static int parse_kernel_probe_opts(const char *source,
+		struct lttng_kernel_probe_location **location)
+{
+	int ret = 0;
+	int match;
+	char s_hex[19];
+	char name[LTTNG_SYMBOL_NAME_LEN];
+	char *symbol_name = NULL;
+	uint64_t offset;
+
+	/* Check for symbol+offset */
+	match = sscanf(source, "%255[^'+']+%18s", name, s_hex);
+	if (match == 2) {
+		if (*s_hex == '\0') {
+			ERR("Kernel probe symbol offset is missing.");
+			goto error;
+		}
+		symbol_name = strndup(name, LTTNG_SYMBOL_NAME_LEN);
+		if (!symbol_name) {
+			ERR("Strndup kernel probe location symbol name.");
+			goto error;
+		}
+		offset = strtoul(s_hex, NULL, 0);
+
+		*location = lttng_kernel_probe_location_symbol_create(
+				symbol_name, offset);
+		if (!location) {
+			ERR("Symbol kernel probe location creation failed.");
+			goto error;
+		}
+
+		goto end;
+	}
+
+	/* Check for symbol */
+	if (isalpha(name[0]) || name[0] == '_') {
+		match = sscanf(source,
+				"%" LTTNG_SYMBOL_NAME_LEN_SCANF_IS_A_BROKEN_API
+				"s",
+				name);
+		if (match == 1) {
+			symbol_name = strndup(name, LTTNG_SYMBOL_NAME_LEN);
+			if (!symbol_name) {
+				ERR("Strndup kernel probe location symbol name.");
+				goto error;
+			}
+
+			*location = lttng_kernel_probe_location_symbol_create(
+					symbol_name, 0);
+			if (!location) {
+				ERR("Symbol kernel probe location creation failed.");
+				goto error;
+			}
+
+			goto end;
+		}
+	}
+
+	/* Check for address */
+	match = sscanf(source, "%18s", s_hex);
+	if (match > 0) {
+		uint64_t address;
+		if (*s_hex == '\0') {
+			ERR("Invalid kernel probe location address.");
+			goto error;
+		}
+		address = strtoul(s_hex, NULL, 0);
+		*location = lttng_kernel_probe_location_address_create(address);
+		if (!location) {
+			ERR("Symbol kernel probe location creation failed.");
+			goto error;
+		}
+
+		goto end;
+	}
+
+error:
+	/* No match */
+	ret = -1;
+	*location = NULL;
+
+end:
+	free(symbol_name);
+	return ret;
+}
+
+static
+struct lttng_event_expr *ir_op_load_expr_to_event_expr(
+		struct ir_load_expression *load_exp, const char *capture_str)
+{
+	struct ir_load_expression_op *load_expr_op = load_exp->child;
+	struct lttng_event_expr *event_expr = NULL;
+	char *provider_name = NULL;
+
+	switch (load_expr_op->type) {
+	case IR_LOAD_EXPRESSION_GET_PAYLOAD_ROOT:
+	{
+		const char *field_name;
+
+		load_expr_op = load_expr_op->next;
+		assert(load_expr_op);
+		assert(load_expr_op->type == IR_LOAD_EXPRESSION_GET_SYMBOL);
+		field_name = load_expr_op->u.symbol;
+		assert(field_name);
+
+		event_expr = lttng_event_expr_event_payload_field_create(field_name);
+		if (!event_expr) {
+			fprintf(stderr, "Failed to create payload field event expression.\n");
+			goto error;
+		}
+
+		break;
+	}
+
+	case IR_LOAD_EXPRESSION_GET_CONTEXT_ROOT:
+	{
+		const char *field_name;
+
+		load_expr_op = load_expr_op->next;
+		assert(load_expr_op);
+		assert(load_expr_op->type == IR_LOAD_EXPRESSION_GET_SYMBOL);
+		field_name = load_expr_op->u.symbol;
+		assert(field_name);
+
+		event_expr = lttng_event_expr_channel_context_field_create(field_name);
+		if (!event_expr) {
+			fprintf(stderr, "Failed to create channel context field event expression.\n");
+			goto error;
+		}
+
+		break;
+	}
+
+	case IR_LOAD_EXPRESSION_GET_APP_CONTEXT_ROOT:
+	{
+		const char *field_name;
+		const char *colon;
+		const char *type_name;
+
+		load_expr_op = load_expr_op->next;
+		assert(load_expr_op);
+		assert(load_expr_op->type == IR_LOAD_EXPRESSION_GET_SYMBOL);
+		field_name = load_expr_op->u.symbol;
+		assert(field_name);
+
+		/*
+		 * The field name needs to be of the form PROVIDER:TYPE.  We
+		 * split it here.
+		 */
+		colon = strchr(field_name, ':');
+		if (!colon) {
+			fprintf(stderr, "Invalid app-specific context field name: missing colon in `%s`.\n",
+				field_name);
+			goto error;
+		}
+
+		type_name = colon + 1;
+		if (*type_name == '\0') {
+			fprintf(stderr,
+				"Invalid app-specific context field name: missing type name after colon in `%s`.\n",
+				field_name);
+			goto error;
+		}
+
+		provider_name = strndup(field_name, colon - field_name);
+		if (!provider_name) {
+			fprintf(stderr, "Failed to allocate string.\n");
+			goto error;
+		}
+
+		event_expr = lttng_event_expr_app_specific_context_field_create(
+			provider_name, type_name);
+		if (!event_expr) {
+			fprintf(stderr,
+				"Failed to create app-specific context field event expression.\n");
+			goto error;
+		}
+
+		break;
+	}
+
+	default:
+		fprintf(stderr, "%s: unexpected load expr type %d.\n",
+			__func__, load_expr_op->type);
+		abort();
+	}
+
+	load_expr_op = load_expr_op->next;
+
+	/* There may be a single array index after that.  */
+	if (load_expr_op->type == IR_LOAD_EXPRESSION_GET_INDEX) {
+		uint64_t index = load_expr_op->u.index;
+		struct lttng_event_expr *index_event_expr;
+
+		index_event_expr = lttng_event_expr_array_field_element_create(event_expr, index);
+		if (!index_event_expr) {
+			fprintf(stderr, "Failed to create array field element event expression.\n");
+			goto error;
+		}
+
+		event_expr = index_event_expr;
+		load_expr_op = load_expr_op->next;
+	}
+
+	switch (load_expr_op->type) {
+	case IR_LOAD_EXPRESSION_LOAD_FIELD:
+		/*
+		 * This is what we expect, IR_LOAD_EXPRESSION_LOAD_FIELD is
+		 * always found at the end of the chain.
+		 */
+		break;
+	case IR_LOAD_EXPRESSION_GET_SYMBOL:
+		fprintf(stderr, "Error: While parsing expression `%s`: Capturing subfields is not supported.\n",
+			capture_str);
+		goto error;
+
+	default:
+		fprintf(stderr, "%s: unexpected load expression operator %s.\n",
+			__func__, ir_load_expression_type_str(load_expr_op->type));
+		abort();
+	}
+
+	goto end;
+
+error:
+	lttng_event_expr_destroy(event_expr);
+	event_expr = NULL;
+
+end:
+	free(provider_name);
+
+	return event_expr;
+}
+
+static
+struct lttng_event_expr *ir_op_load_to_event_expr(struct ir_op *ir,
+		const char *capture_str)
+{
+	struct lttng_event_expr *event_expr = NULL;
+
+	assert(ir->op == IR_OP_LOAD);
+
+	switch (ir->data_type) {
+	case IR_DATA_EXPRESSION:
+	{
+		struct ir_load_expression *ir_load_expr = ir->u.load.u.expression;
+		event_expr = ir_op_load_expr_to_event_expr(ir_load_expr, capture_str);
+		break;
+	}
+
+	default:
+		fprintf(stderr, "%s: unexpected data type: %s.\n", __func__,
+			ir_data_type_str(ir->data_type));
+		abort();
+	}
+
+	return event_expr;
+}
+
+static
+struct lttng_event_expr *ir_op_root_to_event_expr(struct ir_op *ir,
+		const char *capture_str)
+{
+	struct lttng_event_expr *event_expr = NULL;
+
+	assert(ir->op == IR_OP_ROOT);
+	ir = ir->u.root.child;
+
+	switch (ir->op) {
+	case IR_OP_LOAD:
+		event_expr = ir_op_load_to_event_expr(ir, capture_str);
+		break;
+
+	case IR_OP_BINARY:
+		fprintf(stderr, "Error: While parsing expression `%s`: Binary operators are not allowed in capture expressions.\n",
+			capture_str);
+		break;
+
+	case IR_OP_UNARY:
+		fprintf(stderr, "Error: While parsing expression `%s`: Unary operators are not allowed in capture expressions.\n",
+			capture_str);
+		break;
+
+	case IR_OP_LOGICAL:
+		fprintf(stderr, "Error: While parsing expression `%s`: Logical operators are not allowed in capture expressions.\n",
+			capture_str);
+		break;
+
+	default:
+		fprintf(stderr, "%s: unexpected IR op type: %s.\n", __func__,
+			ir_op_type_str(ir->op));
+		abort();
+	}
+
+	return event_expr;
+}
+
+static
+void destroy_event_expr(void *ptr)
+{
+	lttng_event_expr_destroy(ptr);
+}
+
+struct parse_event_rule_res {
+	/* Owned by this */
+	struct lttng_event_rule *er;
+
+	/* Array of `struct lttng_event_expr *` */
+	struct lttng_dynamic_pointer_array capture_descriptors;
+};
+
+static
+struct parse_event_rule_res parse_event_rule(int *argc, const char ***argv)
+{
+	enum lttng_domain_type domain_type = LTTNG_DOMAIN_NONE;
+	enum lttng_event_rule_type event_rule_type = LTTNG_EVENT_RULE_TYPE_UNKNOWN;
+	struct argpar_state *state;
+	struct argpar_item *item = NULL;
+	char *error = NULL;
+	int consumed_args = -1;
+	struct lttng_kernel_probe_location *kernel_probe_location = NULL;
+	struct lttng_userspace_probe_location *userspace_probe_location = NULL;
+	struct parse_event_rule_res res = { 0 };
+	struct lttng_event_expr *event_expr = NULL;
+	struct filter_parser_ctx *parser_ctx = NULL;
+
+	/* Was the -a/--all flag provided? */
+	bool all_events = false;
+
+	/* Tracepoint name (non-option argument) */
+	const char *tracepoint_name = NULL;
+
+	/* Holds the argument of --probe / --userspace-probe. */
+	char *source = NULL;
+
+	/* Filter */
+	char *filter = NULL;
+
+	/* Exclude */
+	char *exclude = NULL;
+	char **exclusion_list = NULL;
+
+	/* Log level */
+	char *loglevel_str = NULL;
+	bool loglevel_only = false;
+
+	lttng_dynamic_pointer_array_init(&res.capture_descriptors,
+				destroy_event_expr);
+	state = argpar_state_create(*argc, *argv, event_rule_opt_descrs);
+	if (!state) {
+		ERR("Failed to allocate an argpar state.");
+		goto error;
+	}
+
+	while (true) {
+		enum argpar_state_parse_next_status status;
+
+		ARGPAR_ITEM_DESTROY_AND_RESET(item);
+		status = argpar_state_parse_next(state, &item, &error);
+		if (status == ARGPAR_STATE_PARSE_NEXT_STATUS_ERROR) {
+			ERR("%s", error);
+			goto error;
+		} else if (status == ARGPAR_STATE_PARSE_NEXT_STATUS_ERROR_UNKNOWN_OPT) {
+			/* Just stop parsing here. */
+			break;
+		} else if (status == ARGPAR_STATE_PARSE_NEXT_STATUS_END) {
+			break;
+		}
+
+		assert(status == ARGPAR_STATE_PARSE_NEXT_STATUS_OK);
+
+		if (item->type == ARGPAR_ITEM_TYPE_OPT) {
+			struct argpar_item_opt *item_opt =
+				(struct argpar_item_opt *) item;
+
+			switch (item_opt->descr->id) {
+			/* Domains */
+			case OPT_USERSPACE:
+				if (!assign_domain_type(&domain_type, LTTNG_DOMAIN_UST)) {
+					goto error;
+				}
+				break;
+
+			case OPT_KERNEL:
+				if (!assign_domain_type(&domain_type, LTTNG_DOMAIN_KERNEL)) {
+					goto error;
+				}
+				break;
+
+			case OPT_LOG4J:
+				if (!assign_domain_type(&domain_type, LTTNG_DOMAIN_LOG4J)) {
+					goto error;
+				}
+				break;
+
+			case OPT_JUL:
+				if (!assign_domain_type(&domain_type, LTTNG_DOMAIN_JUL)) {
+					goto error;
+				}
+				break;
+
+			case OPT_PYTHON:
+				if (!assign_domain_type(&domain_type, LTTNG_DOMAIN_PYTHON)) {
+					goto error;
+				}
+				break;
+
+			/* Event rule types */
+			case OPT_FUNCTION:
+				if (!assign_event_rule_type(&event_rule_type,
+						LTTNG_EVENT_RULE_TYPE_KRETPROBE)) {
+					goto error;
+				}
+				break;
+
+			case OPT_PROBE:
+				if (!assign_event_rule_type(&event_rule_type,
+						LTTNG_EVENT_RULE_TYPE_KPROBE)) {
+					goto error;
+				}
+
+				if (!assign_string(&source, item_opt->arg, "source")) {
+					goto error;
+				}
+
+				break;
+
+			case OPT_USERSPACE_PROBE:
+				if (!assign_event_rule_type(&event_rule_type,
+						LTTNG_EVENT_RULE_TYPE_UPROBE)) {
+					goto error;
+				}
+
+				if (!assign_string(&source, item_opt->arg, "source")) {
+						goto error;
+				}
+				break;
+
+			case OPT_SYSCALL:
+				if (!assign_event_rule_type(&event_rule_type,
+						LTTNG_EVENT_RULE_TYPE_SYSCALL)) {
+					goto error;
+				}
+				break;
+
+			case OPT_TRACEPOINT:
+				if (!assign_event_rule_type(&event_rule_type,
+						LTTNG_EVENT_RULE_TYPE_TRACEPOINT)) {
+					goto error;
+				}
+				break;
+
+			case OPT_ALL:
+				all_events = true;
+				break;
+
+			case OPT_FILTER:
+				if (!assign_string(&filter, item_opt->arg, "--filter/-f")) {
+					goto error;
+				}
+				break;
+
+			case OPT_EXCLUDE:
+				if (!assign_string(&exclude, item_opt->arg, "--exclude/-x")) {
+					goto error;
+				}
+				break;
+
+			case OPT_LOGLEVEL:
+			case OPT_LOGLEVEL_ONLY:
+				if (!assign_string(&loglevel_str, item_opt->arg, "--loglevel/--loglevel-only")) {
+					goto error;
+				}
+
+				loglevel_only = item_opt->descr->id == OPT_LOGLEVEL_ONLY;
+				break;
+
+			case OPT_CAPTURE:
+			{
+				const char *capture_str = item_opt->arg;
+				int ret;
+
+				ret = filter_parser_ctx_create_from_filter_expression(
+					capture_str, &parser_ctx);
+				if (ret) {
+					fprintf(stderr, "Failed to parse capture expression `%s`.\n", capture_str);
+					goto error;
+				}
+
+				event_expr = ir_op_root_to_event_expr(parser_ctx->ir_root,
+					capture_str);
+				if (!event_expr) {
+					/* ir_op_root_to_event_expr has printed an error message. */
+					goto error;
+				}
+
+				ret = lttng_dynamic_pointer_array_add_pointer(
+						&res.capture_descriptors,
+						event_expr);
+				if (ret) {
+					goto error;
+				}
+
+				/* The ownership of event expression was transferred to the dynamic array. */
+				event_expr = NULL;
+
+				break;
+			}
+
+			default:
+				abort();
+			}
+		} else {
+			struct argpar_item_non_opt *item_non_opt =
+				(struct argpar_item_non_opt *) item;
+
+			/*
+			 * Don't accept two non-option arguments/tracepoint
+			 * names.
+			 */
+			if (tracepoint_name) {
+				ERR(
+					"Unexpected argument: %s",
+					item_non_opt->arg);
+				goto error;
+			}
+
+			tracepoint_name = item_non_opt->arg;
+		}
+	}
+
+	if (event_rule_type == LTTNG_EVENT_RULE_TYPE_UNKNOWN) {
+		event_rule_type = LTTNG_EVENT_RULE_TYPE_TRACEPOINT;
+	}
+
+	/*
+	 * Option -a is applicable to event rules of type tracepoint and
+	 * syscall, and it is equivalent to using "*" as the tracepoint name.
+	 */
+	if (all_events) {
+		switch (event_rule_type) {
+		case LTTNG_EVENT_RULE_TYPE_TRACEPOINT:
+		case LTTNG_EVENT_RULE_TYPE_SYSCALL:
+			break;
+		default:
+			ERR("Can't use -a/--all with event rule of type %s.",
+				lttng_event_rule_type_str(event_rule_type));
+			goto error;
+		}
+
+		if (tracepoint_name) {
+			ERR("Can't provide a tracepoint name with -a/--all.");
+			goto error;
+		}
+
+		/* In which case, it's equivalent to tracepoint name "*". */
+		tracepoint_name = "*";
+	}
+
+	/*
+	 * A tracepoint name (or -a, for the event rule types that accept it)
+	 * is required.
+	 */
+	if (!tracepoint_name) {
+		ERR("Need to provide either a tracepoint name or -a/--all.");
+		goto error;
+	}
+
+	/*
+	 * We don't support multiple tracepoint names for now.
+	 */
+	if (strchr(tracepoint_name, ',')) {
+		ERR("multiple tracepoint names are not supported at the moment.");
+		goto error;
+	}
+
+	/*
+	 * Update *argc and *argv so our caller can keep parsing what follows.
+	 */
+	consumed_args = argpar_state_get_ingested_orig_args(state);
+	assert(consumed_args >= 0);
+	*argc -= consumed_args;
+	*argv += consumed_args;
+
+	/* Need to specify a domain. */
+	if (domain_type == LTTNG_DOMAIN_NONE) {
+		ERR("Please specify a domain (-k/-u/-j).");
+		goto error;
+	}
+
+	/* Validate event rule type against domain. */
+	switch (event_rule_type) {
+	case LTTNG_EVENT_RULE_TYPE_KPROBE:
+	case LTTNG_EVENT_RULE_TYPE_KRETPROBE:
+	case LTTNG_EVENT_RULE_TYPE_UPROBE:
+	case LTTNG_EVENT_RULE_TYPE_SYSCALL:
+		if (domain_type != LTTNG_DOMAIN_KERNEL) {
+			ERR("Event type not available for user-space tracing");
+			goto error;
+		}
+		break;
+
+	case LTTNG_EVENT_RULE_TYPE_TRACEPOINT:
+		break;
+
+	default:
+		abort();
+	}
+
+	/*
+	 * Adding a filter to a probe, function or userspace-probe would be
+	 * denied by the kernel tracer as it's not supported at the moment. We
+	 * do an early check here to warn the user.
+	 */
+	if (filter && domain_type == LTTNG_DOMAIN_KERNEL) {
+		switch (event_rule_type) {
+		case LTTNG_EVENT_RULE_TYPE_TRACEPOINT:
+		case LTTNG_EVENT_RULE_TYPE_SYSCALL:
+			break;
+		default:
+			ERR("Filter expressions are not supported for %s events",
+					lttng_event_rule_type_str(event_rule_type));
+			goto error;
+		}
+	}
+
+	/* If --exclude/-x was passed, split it into an exclusion list. */
+	if (exclude) {
+		if (domain_type != LTTNG_DOMAIN_UST) {
+			ERR("Event name exclusions are not yet implemented for %s events",
+						get_domain_str(domain_type));
+			goto error;
+		}
+
+
+		if (create_exclusion_list_and_validate(tracepoint_name, exclude,
+				&exclusion_list) != 0) {
+			ERR("Failed to create exclusion list.");
+			goto error;
+		}
+	}
+
+	if (loglevel_str && event_rule_type != LTTNG_EVENT_RULE_TYPE_TRACEPOINT) {
+		ERR("Log levels are only application to tracepoint event rules.");
+		goto error;
+	}
+
+	/* Finally, create the event rule object. */
+	switch (event_rule_type) {
+	case LTTNG_EVENT_RULE_TYPE_TRACEPOINT:
+	{
+		enum lttng_event_rule_status event_rule_status;
+
+		res.er = lttng_event_rule_tracepoint_create(domain_type);
+		if (!res.er) {
+			ERR("Failed to create tracepoint event rule.");
+			goto error;
+		}
+
+		/* Set pattern. */
+		event_rule_status =
+			lttng_event_rule_tracepoint_set_pattern(res.er, tracepoint_name);
+		if (event_rule_status != LTTNG_EVENT_RULE_STATUS_OK) {
+			ERR("Failed to set tracepoint pattern.");
+			goto error;
+		}
+
+		/* Set filter. */
+		if (filter) {
+			event_rule_status =
+				lttng_event_rule_tracepoint_set_filter(
+					res.er, filter);
+			if (event_rule_status != LTTNG_EVENT_RULE_STATUS_OK) {
+				ERR("Failed to set tracepoint filter expression.");
+				goto error;
+			}
+		}
+
+		/* Set exclusion list. */
+		if (exclusion_list) {
+			int n;
+
+			for (n = 0; exclusion_list[n]; n++) {
+				event_rule_status = lttng_event_rule_tracepoint_add_exclusion(
+						res.er,
+						exclusion_list[n]);
+				if (event_rule_status !=
+						LTTNG_EVENT_RULE_STATUS_OK) {
+					ERR("Failed to set tracepoint exclusion list.");
+					goto error;
+				}
+			}
+		}
+
+		if (loglevel_str) {
+			int loglevel;
+
+			if (domain_type == LTTNG_DOMAIN_KERNEL) {
+				ERR("Log levels are not supported by the kernel tracer.");
+				goto error;
+			}
+
+			loglevel = parse_loglevel_string(
+				loglevel_str, domain_type);
+			if (loglevel < 0) {
+				ERR("Failed to parse `%s` as a log level.", loglevel_str);
+				goto error;
+			}
+
+			if (loglevel_only) {
+				event_rule_status =
+					lttng_event_rule_tracepoint_set_log_level(
+						res.er, loglevel);
+			} else {
+				event_rule_status =
+					lttng_event_rule_tracepoint_set_log_level_range_lower_bound(
+						res.er, loglevel);
+			}
+
+			if (event_rule_status != LTTNG_EVENT_RULE_STATUS_OK) {
+				ERR("Failed to set log level.");
+				goto error;
+			}
+		}
+
+		break;
+	}
+
+	case LTTNG_EVENT_RULE_TYPE_KPROBE:
+	{
+		int ret;
+		enum lttng_event_rule_status event_rule_status;
+
+		res.er = lttng_event_rule_kprobe_create();
+		if (!res.er) {
+			ERR("Failed to create kprobe event rule.");
+			goto error;
+		}
+
+		ret = parse_kernel_probe_opts(source, &kernel_probe_location);
+		if (ret) {
+			ERR("Failed to parse kernel probe location.");
+			goto error;
+		}
+
+		event_rule_status = lttng_event_rule_kprobe_set_name(res.er, tracepoint_name);
+		if (event_rule_status != LTTNG_EVENT_RULE_STATUS_OK) {
+			ERR("Failed to set kprobe event rule's name.");
+			goto error;
+		}
+
+		assert(kernel_probe_location);
+		event_rule_status = lttng_event_rule_kprobe_set_location(res.er, kernel_probe_location);
+		if (event_rule_status != LTTNG_EVENT_RULE_STATUS_OK) {
+			ERR("Failed to set kprobe event rule's location.");
+			goto error;
+		}
+
+		break;
+	}
+
+	case LTTNG_EVENT_RULE_TYPE_UPROBE:
+	{
+		int ret;
+		enum lttng_event_rule_status event_rule_status;
+
+		ret = parse_userspace_probe_opts(source, &userspace_probe_location);
+		if (ret) {
+			ERR("Failed to parse userspace probe location.");
+			goto error;
+		}
+
+		res.er = lttng_event_rule_uprobe_create();
+		if (!res.er) {
+			ERR("Failed to create userspace probe event rule.");
+			goto error;
+		}
+
+		event_rule_status = lttng_event_rule_uprobe_set_location(res.er, userspace_probe_location);
+		if (event_rule_status != LTTNG_EVENT_RULE_STATUS_OK) {
+			ERR("Failed to set userspace probe event rule's location.");
+			goto error;
+		}
+
+		event_rule_status = lttng_event_rule_uprobe_set_name(res.er, tracepoint_name);
+		if (event_rule_status != LTTNG_EVENT_RULE_STATUS_OK) {
+			ERR("Failed to set userspace probe event rule's name.");
+			goto error;
+		}
+
+		break;
+	}
+
+	case LTTNG_EVENT_RULE_TYPE_SYSCALL:
+	{
+		enum lttng_event_rule_status event_rule_status;
+
+		res.er = lttng_event_rule_syscall_create();
+		if (!res.er) {
+			ERR("Failed to create syscall event rule.");
+			goto error;
+		}
+
+		event_rule_status = lttng_event_rule_syscall_set_pattern(res.er, tracepoint_name);
+		if (event_rule_status != LTTNG_EVENT_RULE_STATUS_OK) {
+			ERR("Failed to set syscall event rule's pattern.");
+			goto error;
+		}
+
+		if (filter) {
+			event_rule_status = lttng_event_rule_syscall_set_filter(
+					res.er, filter);
+			if (event_rule_status != LTTNG_EVENT_RULE_STATUS_OK) {
+				ERR("Failed to set syscall event rule's filter expression.");
+				goto error;
+			}
+		}
+
+		break;
+	}
+
+	default:
+		ERR("%s: I don't support event rules of type `%s` at the moment.", __func__,
+			lttng_event_rule_type_str(event_rule_type));
+		goto error;
+	}
+
+	goto end;
+
+error:
+	lttng_event_rule_destroy(res.er);
+	res.er = NULL;
+	lttng_dynamic_pointer_array_reset(&res.capture_descriptors);
+
+end:
+	if (parser_ctx) {
+		filter_parser_ctx_free(parser_ctx);
+	}
+
+	lttng_event_expr_destroy(event_expr);
+	argpar_item_destroy(item);
+	free(error);
+	argpar_state_destroy(state);
+	free(filter);
+	free(exclude);
+	free(loglevel_str);
+	strutils_free_null_terminated_array_of_strings(exclusion_list);
+	lttng_kernel_probe_location_destroy(kernel_probe_location);
+	lttng_userspace_probe_location_destroy(userspace_probe_location);
+	return res;
+}
+
+static
+struct lttng_condition *handle_condition_event(int *argc, const char ***argv)
+{
+	struct parse_event_rule_res res;
+	struct lttng_condition *c;
+	size_t i;
+
+	res = parse_event_rule(argc, argv);
+	if (!res.er) {
+		c = NULL;
+		goto error;
+	}
+
+	c = lttng_condition_event_rule_create(res.er);
+	if (!c) {
+		goto error;
+	}
+
+	for (i = 0; i < lttng_dynamic_pointer_array_get_count(&res.capture_descriptors);
+			i++) {
+		enum lttng_condition_status status;
+		struct lttng_event_expr **expr =
+				lttng_dynamic_array_get_element(
+					&res.capture_descriptors.array, i);
+
+		assert(expr);
+		assert(*expr);
+		status = lttng_condition_event_rule_append_capture_descriptor(
+				c, *expr);
+		if (status != LTTNG_CONDITION_STATUS_OK) {
+			if (status == LTTNG_CONDITION_STATUS_UNSUPPORTED) {
+				ERR("The capture feature is unsupported by the event-rule type");
+			}
+			goto error;
+		}
+
+		/* Ownership of event expression moved to `c` */
+		*expr = NULL;
+	}
+
+	goto end;
+
+error:
+	lttng_condition_destroy(c);
+	c = NULL;
+
+end:
+	lttng_dynamic_pointer_array_reset(&res.capture_descriptors);
+	lttng_event_rule_destroy(res.er);
+	return c;
+}
+
+static
+struct lttng_condition *handle_condition_session_consumed_size(int *argc, const char ***argv)
+{
+	struct lttng_condition *cond = NULL;
+	struct argpar_state *state = NULL;
+	struct argpar_item *item = NULL;
+	const char *threshold_arg = NULL;
+	const char *session_name_arg = NULL;
+	uint64_t threshold;
+	char *error = NULL;
+	enum lttng_condition_status condition_status;
+
+	state = argpar_state_create(*argc, *argv, event_rule_opt_descrs);
+	if (!state) {
+		ERR("Failed to allocate an argpar state.");
+		goto error;
+	}
+
+	while (true) {
+		enum argpar_state_parse_next_status status;
+
+		ARGPAR_ITEM_DESTROY_AND_RESET(item);
+		status = argpar_state_parse_next(state, &item, &error);
+		if (status == ARGPAR_STATE_PARSE_NEXT_STATUS_ERROR) {
+			ERR("%s", error);
+			goto error;
+		} else if (status == ARGPAR_STATE_PARSE_NEXT_STATUS_ERROR_UNKNOWN_OPT) {
+			/* Just stop parsing here. */
+			break;
+		} else if (status == ARGPAR_STATE_PARSE_NEXT_STATUS_END) {
+			break;
+		}
+
+		assert(status == ARGPAR_STATE_PARSE_NEXT_STATUS_OK);
+
+		if (item->type == ARGPAR_ITEM_TYPE_OPT) {
+			struct argpar_item_opt *item_opt =
+				(struct argpar_item_opt *) item;
+
+			switch (item_opt->descr->id) {
+			default:
+				abort();
+			}
+		} else {
+			struct argpar_item_non_opt *item_non_opt;
+
+			assert(item->type == ARGPAR_ITEM_TYPE_NON_OPT);
+
+			item_non_opt = (struct argpar_item_non_opt *) item;
+
+			switch (item_non_opt->non_opt_index) {
+			case 0:
+				session_name_arg = item_non_opt->arg;
+				break;
+			case 1:
+				threshold_arg = item_non_opt->arg;
+				break;
+			default:
+				ERR("Unexpected argument `%s`.",
+					item_non_opt->arg);
+				goto error;
+			}
+		}
+	}
+
+	*argc -= argpar_state_get_ingested_orig_args(state);
+	*argv += argpar_state_get_ingested_orig_args(state);
+
+	if (!session_name_arg) {
+		ERR("Missing session name argument.");
+		goto error;
+	}
+
+	if (!threshold_arg) {
+		ERR("Missing threshold argument.");
+		goto error;
+	}
+
+	if (utils_parse_size_suffix(threshold_arg, &threshold) != 0) {
+		ERR("Failed to parse `%s` as a size.", threshold_arg);
+		goto error;
+	}
+
+	cond = lttng_condition_session_consumed_size_create();
+	if (!cond) {
+		ERR("Failed to allocate a session consumed size condition.");
+		goto error;
+	}
+
+	condition_status = lttng_condition_session_consumed_size_set_session_name(
+		cond, session_name_arg);
+	if (condition_status != LTTNG_CONDITION_STATUS_OK) {
+		ERR("Failed to set session consumed size condition session name.");
+		goto error;
+	}
+
+
+	condition_status = lttng_condition_session_consumed_size_set_threshold(
+		cond, threshold);
+	if (condition_status != LTTNG_CONDITION_STATUS_OK) {
+		ERR("Failed to set session consumed size condition threshold.");
+		goto error;
+	}
+
+	goto end;
+
+error:
+	lttng_condition_destroy(cond);
+	cond = NULL;
+
+end:
+	argpar_state_destroy(state);
+	argpar_item_destroy(item);
+	free(error);
+	return cond;
+}
+
+static
+struct lttng_condition *handle_condition_buffer_usage_high(int *argc, const char ***argv)
+{
+	struct lttng_condition *cond = NULL;
+	struct argpar_state *state = NULL;
+	struct argpar_item *item = NULL;
+	const char *threshold_arg = NULL;
+	const char *session_name_arg = NULL;
+	uint64_t threshold;
+	char *error = NULL;
+	enum lttng_condition_status condition_status;
+
+	state = argpar_state_create(*argc, *argv, event_rule_opt_descrs);
+	if (!state) {
+		ERR("Failed to allocate an argpar state.");
+		goto error;
+	}
+
+	while (true) {
+		enum argpar_state_parse_next_status status;
+
+		ARGPAR_ITEM_DESTROY_AND_RESET(item);
+		status = argpar_state_parse_next(state, &item, &error);
+		if (status == ARGPAR_STATE_PARSE_NEXT_STATUS_ERROR) {
+			ERR("%s", error);
+			goto error;
+		} else if (status == ARGPAR_STATE_PARSE_NEXT_STATUS_ERROR_UNKNOWN_OPT) {
+			/* Just stop parsing here. */
+			break;
+		} else if (status == ARGPAR_STATE_PARSE_NEXT_STATUS_END) {
+			break;
+		}
+
+		assert(status == ARGPAR_STATE_PARSE_NEXT_STATUS_OK);
+
+		if (item->type == ARGPAR_ITEM_TYPE_OPT) {
+			struct argpar_item_opt *item_opt =
+				(struct argpar_item_opt *) item;
+
+			switch (item_opt->descr->id) {
+			default:
+				abort();
+			}
+		} else {
+			struct argpar_item_non_opt *item_non_opt;
+
+			assert(item->type == ARGPAR_ITEM_TYPE_NON_OPT);
+
+			item_non_opt = (struct argpar_item_non_opt *) item;
+
+			switch (item_non_opt->non_opt_index) {
+			case 0:
+				session_name_arg = item_non_opt->arg;
+				break;
+			case 1:
+				threshold_arg = item_non_opt->arg;
+				break;
+			default:
+				ERR("Unexpected argument `%s`.",
+					item_non_opt->arg);
+				goto error;
+			}
+		}
+	}
+
+	*argc -= argpar_state_get_ingested_orig_args(state);
+	*argv += argpar_state_get_ingested_orig_args(state);
+
+	if (!session_name_arg) {
+		ERR("Missing session name argument.");
+		goto error;
+	}
+
+	if (!threshold_arg) {
+		ERR("Missing threshold argument.");
+		goto error;
+	}
+
+	if (utils_parse_size_suffix(threshold_arg, &threshold) != 0) {
+		ERR("Failed to parse `%s` as a size.", threshold_arg);
+		goto error;
+	}
+
+	cond = lttng_condition_session_consumed_size_create();
+	if (!cond) {
+		ERR("Failed to allocate a session consumed size condition.");
+		goto error;
+	}
+
+	condition_status = lttng_condition_session_consumed_size_set_session_name(
+		cond, session_name_arg);
+	if (condition_status != LTTNG_CONDITION_STATUS_OK) {
+		ERR("Failed to set session consumed size condition session name.");
+		goto error;
+	}
+
+	condition_status = lttng_condition_session_consumed_size_set_threshold(
+		cond, threshold);
+	if (condition_status != LTTNG_CONDITION_STATUS_OK) {
+		ERR("Failed to set session consumed size condition threshold.");
+		goto error;
+	}
+
+	goto end;
+
+error:
+	lttng_condition_destroy(cond);
+	cond = NULL;
+
+end:
+	argpar_state_destroy(state);
+	argpar_item_destroy(item);
+	free(error);
+	return cond;
+}
+
+static
+struct lttng_condition *handle_condition_buffer_usage_low(int *argc, const char ***argv)
+{
+	return NULL;
+}
+
+static
+struct lttng_condition *handle_condition_session_rotation_ongoing(int *argc, const char ***argv)
+{
+	return NULL;
+}
+
+static
+struct lttng_condition *handle_condition_session_rotation_completed(int *argc, const char ***argv)
+{
+	return NULL;
+}
+
+struct condition_descr {
+	const char *name;
+	struct lttng_condition *(*handler) (int *argc, const char ***argv);
+};
+
+static const
+struct condition_descr condition_descrs[] = {
+	{ "on-event", handle_condition_event },
+	{ "on-session-consumed-size", handle_condition_session_consumed_size },
+	{ "on-buffer-usage-high", handle_condition_buffer_usage_high },
+	{ "on-buffer-usage-low", handle_condition_buffer_usage_low },
+	{ "on-session-rotation-ongoing", handle_condition_session_rotation_ongoing },
+	{ "on-session-rotation-completed", handle_condition_session_rotation_completed },
+};
+
+static
+struct lttng_condition *parse_condition(int *argc, const char ***argv)
+{
+	int i;
+	struct lttng_condition *cond;
+	const char *condition_name;
+	const struct condition_descr *descr = NULL;
+
+	if (*argc == 0) {
+		ERR("Missing condition name.");
+		goto error;
+	}
+
+	condition_name = (*argv)[0];
+
+	(*argc)--;
+	(*argv)++;
+
+	for (i = 0; i < ARRAY_SIZE(condition_descrs); i++) {
+		if (strcmp(condition_name, condition_descrs[i].name) == 0) {
+			descr = &condition_descrs[i];
+			break;
+		}
+	}
+
+	if (!descr) {
+		ERR("Unknown condition name: %s", condition_name);
+		goto error;
+	}
+
+	cond = descr->handler(argc, argv);
+	if (!cond) {
+		/* The handler has already printed an error message. */
+		goto error;
+	}
+
+	goto end;
+error:
+	cond = NULL;
+end:
+	return cond;
+}
+
+
+static
+struct lttng_action *handle_action_notify(int *argc, const char ***argv)
+{
+	return lttng_action_notify_create();
+}
+
+static const struct argpar_opt_descr no_opt_descrs[] = {
+	ARGPAR_OPT_DESCR_SENTINEL
+};
+
+/*
+ * Generic handler for a kind of action that takes a session name as its sole
+ * argument.
+ */
+
+static
+struct lttng_action *handle_action_simple_session(
+		int *argc, const char ***argv,
+		struct lttng_action *(*create_action_cb)(void),
+		enum lttng_action_status (*set_session_name_cb)(struct lttng_action *, const char *),
+		const char *action_name)
+{
+	struct lttng_action *action = NULL;
+	struct argpar_state *state = NULL;
+	struct argpar_item *item = NULL;
+	const char *session_name_arg = NULL;
+	char *error = NULL;
+	enum lttng_action_status action_status;
+
+	state = argpar_state_create(*argc, *argv, no_opt_descrs);
+	if (!state) {
+		ERR("Failed to allocate an argpar state.");
+		goto error;
+	}
+
+	while (true) {
+		enum argpar_state_parse_next_status status;
+		struct argpar_item_non_opt *item_non_opt;
+
+		ARGPAR_ITEM_DESTROY_AND_RESET(item);
+		status = argpar_state_parse_next(state, &item, &error);
+		if (status == ARGPAR_STATE_PARSE_NEXT_STATUS_ERROR) {
+			ERR("%s", error);
+			goto error;
+		} else if (status == ARGPAR_STATE_PARSE_NEXT_STATUS_ERROR_UNKNOWN_OPT) {
+			/* Just stop parsing here. */
+			break;
+		} else if (status == ARGPAR_STATE_PARSE_NEXT_STATUS_END) {
+			break;
+		}
+
+		assert(status == ARGPAR_STATE_PARSE_NEXT_STATUS_OK);
+		assert(item->type == ARGPAR_ITEM_TYPE_NON_OPT);
+
+		item_non_opt = (struct argpar_item_non_opt *) item;
+
+		switch (item_non_opt->non_opt_index) {
+		case 0:
+			session_name_arg = item_non_opt->arg;
+			break;
+		default:
+			ERR("Unexpected argument `%s`.",
+				item_non_opt->arg);
+			goto error;
+		}
+	}
+
+	*argc -= argpar_state_get_ingested_orig_args(state);
+	*argv += argpar_state_get_ingested_orig_args(state);
+
+	if (!session_name_arg) {
+		ERR("Missing session name.");
+		goto error;
+	}
+
+	action = create_action_cb();
+	if (!action) {
+		ERR(
+			"Failed to allocate %s session action.", action_name);
+		goto error;
+	}
+
+	action_status = set_session_name_cb(action, session_name_arg);
+	if (action_status != LTTNG_ACTION_STATUS_OK) {
+		ERR(
+			"Failed to set action %s session's session name.",
+			action_name);
+		goto error;
+	}
+
+	goto end;
+
+error:
+	lttng_action_destroy(action);
+	action = NULL;
+
+end:
+	return action;
+}
+
+static
+struct lttng_action *handle_action_start_session(int *argc,
+		const char ***argv)
+{
+	return handle_action_simple_session(argc, argv,
+		lttng_action_start_session_create,
+		lttng_action_start_session_set_session_name,
+		"start");
+}
+
+static
+struct lttng_action *handle_action_stop_session(int *argc,
+		const char ***argv)
+{
+	return handle_action_simple_session(argc, argv,
+		lttng_action_stop_session_create,
+		lttng_action_stop_session_set_session_name,
+		"stop");
+}
+
+static
+struct lttng_action *handle_action_rotate_session(int *argc,
+		const char ***argv)
+{
+	return handle_action_simple_session(argc, argv,
+		lttng_action_rotate_session_create,
+		lttng_action_rotate_session_set_session_name,
+		"rotate");
+}
+
+static const struct argpar_opt_descr snapshot_action_opt_descrs[] = {
+	{ OPT_NAME, 'n', "name", true },
+	{ OPT_MAX_SIZE, 'm', "max-size", true },
+	{ OPT_CTRL_URL, '\0', "ctrl-url", true },
+	{ OPT_DATA_URL, '\0', "data-url", true },
+	ARGPAR_OPT_DESCR_SENTINEL
+};
+
+static
+struct lttng_action *handle_action_snapshot_session(int *argc,
+		const char ***argv)
+{
+	struct lttng_action *action = NULL;
+	struct argpar_state *state = NULL;
+	struct argpar_item *item = NULL;
+	const char *session_name_arg = NULL;
+	char *snapshot_name_arg = NULL;
+	char *ctrl_url_arg = NULL;
+	char *data_url_arg = NULL;
+	char *max_size_arg = NULL;
+	const char *url_arg = NULL;
+	char *error = NULL;
+	enum lttng_action_status action_status;
+	struct lttng_snapshot_output *snapshot_output = NULL;
+	int ret;
+
+	state = argpar_state_create(*argc, *argv, snapshot_action_opt_descrs);
+	if (!state) {
+		ERR("Failed to allocate an argpar state.");
+		goto error;
+	}
+
+	while (true) {
+		enum argpar_state_parse_next_status status;
+
+		ARGPAR_ITEM_DESTROY_AND_RESET(item);
+		status = argpar_state_parse_next(state, &item, &error);
+		if (status == ARGPAR_STATE_PARSE_NEXT_STATUS_ERROR) {
+			ERR("%s", error);
+			goto error;
+		} else if (status == ARGPAR_STATE_PARSE_NEXT_STATUS_ERROR_UNKNOWN_OPT) {
+			/* Just stop parsing here. */
+			break;
+		} else if (status == ARGPAR_STATE_PARSE_NEXT_STATUS_END) {
+			break;
+		}
+
+		assert(status == ARGPAR_STATE_PARSE_NEXT_STATUS_OK);
+
+		if (item->type == ARGPAR_ITEM_TYPE_OPT) {
+			struct argpar_item_opt *item_opt =
+				(struct argpar_item_opt *) item;
+
+			switch (item_opt->descr->id) {
+			case OPT_NAME:
+				if (!assign_string(&snapshot_name_arg, item_opt->arg, "--name/-n")) {
+					goto error;
+				}
+				break;
+
+			case OPT_MAX_SIZE:
+				if (!assign_string(&max_size_arg, item_opt->arg, "--max-size/-m")) {
+					goto error;
+				}
+				break;
+
+			case OPT_CTRL_URL:
+				if (!assign_string(&ctrl_url_arg, item_opt->arg, "--ctrl-url")) {
+					goto error;
+				}
+				break;
+
+			case OPT_DATA_URL:
+				if (!assign_string(&data_url_arg, item_opt->arg, "--data-url")) {
+					goto error;
+				}
+				break;
+
+			default:
+				abort();
+			}
+		} else {
+			struct argpar_item_non_opt *item_non_opt;
+
+			assert(item->type == ARGPAR_ITEM_TYPE_NON_OPT);
+
+			item_non_opt = (struct argpar_item_non_opt *) item;
+
+			switch (item_non_opt->non_opt_index) {
+			case 0:
+				session_name_arg = item_non_opt->arg;
+				break;
+
+			// FIXME: the use of a non-option argument for this is to
+			// follow the syntax of `lttng snapshot record`.  But otherwise,
+			// I think an option argument would be best.
+			case 1:
+				url_arg = item_non_opt->arg;
+				break;
+
+			default:
+				ERR("Unexpected argument `%s`.",
+					item_non_opt->arg);
+				goto error;
+			}
+		}
+	}
+
+	*argc -= argpar_state_get_ingested_orig_args(state);
+	*argv += argpar_state_get_ingested_orig_args(state);
+
+	if (!session_name_arg) {
+		ERR("Missing session name.");
+		goto error;
+	}
+
+	/* --ctrl-url and --data-url must come in pair. */
+	if (ctrl_url_arg && !data_url_arg) {
+		ERR("--ctrl-url is specified, but --data-url is missing.");
+		goto error;
+	}
+
+	if (!ctrl_url_arg && data_url_arg) {
+		ERR("--data-url is specified, but --ctrl-url is missing.");
+		goto error;
+	}
+
+	/* --ctrl-url/--data-url and the non-option URL are mutually exclusive. */
+	if (ctrl_url_arg && url_arg) {
+		ERR("Both --ctrl-url/--data-url and the non-option URL argument "
+				"can't be used together.");
+		goto error;
+	}
+
+	/*
+	 * Did the user specify an option that implies using a
+	 * custom/unregistered output?
+	 */
+	if (url_arg || ctrl_url_arg) {
+		snapshot_output = lttng_snapshot_output_create();
+		if (!snapshot_output) {
+			ERR("Failed to allocate a snapshot output.");
+			goto error;
+		}
+	}
+
+	action = lttng_action_snapshot_session_create();
+	if (!action) {
+		ERR(
+			"Failed to allocate snapshot session action.");
+		goto error;
+	}
+
+	action_status = lttng_action_snapshot_session_set_session_name(
+		action, session_name_arg);
+	if (action_status != LTTNG_ACTION_STATUS_OK) {
+		ERR(
+			"Failed to set action snapshot session's session name.");
+		goto error;
+	}
+
+	if (snapshot_name_arg) {
+		if (!snapshot_output) {
+			ERR("Can't provide a snapshot output name without a snapshot output destination.");
+			goto error;
+		}
+
+		ret = lttng_snapshot_output_set_name(snapshot_name_arg, snapshot_output);
+		if (ret != 0) {
+			ERR("Failed to set name of snapshot output.");
+			goto error;
+		}
+	}
+
+	if (max_size_arg) {
+		uint64_t max_size;
+
+		if (!snapshot_output) {
+			ERR("Can't provide a snapshot output max size without a snapshot output destination.");
+			goto error;
+		}
+
+		ret = utils_parse_size_suffix(max_size_arg, &max_size);
+		if (ret != 0) {
+			ERR("Failed to parse `%s` as a size.", max_size_arg);
+			goto error;
+		}
+
+		ret = lttng_snapshot_output_set_size(max_size, snapshot_output);
+		if (ret != 0) {
+			ERR("Failed to set snapshot output's max size.");
+			goto error;
+		}
+	}
+
+	if (url_arg) {
+		/* One argument form, either net:// / net6:// or a local file path. */
+
+		if (strncmp(url_arg, "net://", strlen("net://")) == 0 ||
+				strncmp(url_arg, "net6://", strlen("net6://")) == 0) {
+			ret = lttng_snapshot_output_set_network_url(
+				url_arg, snapshot_output);
+			if (ret != 0) {
+				ERR("Failed to parse %s as a network URL.", url_arg);
+				goto error;
+			}
+		} else {
+			ret = lttng_snapshot_output_set_local_path(
+				url_arg, snapshot_output);
+			if (ret != 0) {
+				ERR("Failed to parse %s as a local path.", url_arg);
+				goto error;
+			}
+		}
+	}
+
+	if (ctrl_url_arg) {
+		/*
+		 * Two argument form, network output with separate control and
+		 * data URLs.
+		 */
+		ret = lttng_snapshot_output_set_network_urls(
+			ctrl_url_arg, data_url_arg, snapshot_output);
+		if (ret != 0) {
+			ERR("Failed to parse `%s` and `%s` as control and data URLs.",
+				ctrl_url_arg, data_url_arg);
+			goto error;
+		}
+	}
+
+	if (snapshot_output) {
+		action_status = lttng_action_snapshot_session_set_output(
+			action, snapshot_output);
+		if (action_status != LTTNG_ACTION_STATUS_OK) {
+			ERR("Failed to set snapshot session action's output.");
+			goto error;
+		}
+
+		/* Ownership of `snapshot_output` has been transferred to the action. */
+		snapshot_output = NULL;
+	}
+
+	goto end;
+
+error:
+	lttng_action_destroy(action);
+	action = NULL;
+
+end:
+	free(snapshot_name_arg);
+	free(ctrl_url_arg);
+	free(data_url_arg);
+	free(snapshot_output);
+	return action;
+}
+
+struct action_descr {
+	const char *name;
+	struct lttng_action *(*handler) (int *argc, const char ***argv);
+};
+
+static const
+struct action_descr action_descrs[] = {
+	{ "notify", handle_action_notify },
+	{ "start-session", handle_action_start_session },
+	{ "stop-session", handle_action_stop_session },
+	{ "rotate-session", handle_action_rotate_session },
+	{ "snapshot-session", handle_action_snapshot_session },
+};
+
+static
+struct lttng_action *parse_action(int *argc, const char ***argv)
+{
+	int i;
+	struct lttng_action *action;
+	const char *action_name;
+	const struct action_descr *descr = NULL;
+
+	if (*argc == 0) {
+		ERR("Missing action name.");
+		goto error;
+	}
+
+	action_name = (*argv)[0];
+
+	(*argc)--;
+	(*argv)++;
+
+	for (i = 0; i < ARRAY_SIZE(action_descrs); i++) {
+		if (strcmp(action_name, action_descrs[i].name) == 0) {
+			descr = &action_descrs[i];
+			break;
+		}
+	}
+
+	if (!descr) {
+		ERR("Unknown action name: %s", action_name);
+		goto error;
+	}
+
+	action = descr->handler(argc, argv);
+	if (!action) {
+		/* The handler has already printed an error message. */
+		goto error;
+	}
+
+	goto end;
+error:
+	action = NULL;
+end:
+	return action;
+}
+
+static const
+struct argpar_opt_descr add_trigger_options[] = {
+	{ OPT_HELP, 'h', "help", false },
+	{ OPT_LIST_OPTIONS, '\0', "list-options", false },
+	{ OPT_CONDITION, '\0', "condition", false },
+	{ OPT_ACTION, '\0', "action", false },
+	{ OPT_ID, '\0', "id", true },
+	{ OPT_FIRE_ONCE_AFTER, '\0', "fire-once-after", true },
+	{ OPT_FIRE_EVERY, '\0', "fire-every", true },
+	{ OPT_USER_ID, '\0', "user-id", true },
+	ARGPAR_OPT_DESCR_SENTINEL,
+};
+
+static
+void lttng_actions_destructor(void *p)
+{
+	struct lttng_action *action = p;
+
+	lttng_action_destroy(action);
+}
+
+int cmd_add_trigger(int argc, const char **argv)
+{
+	int ret;
+	int my_argc = argc - 1;
+	const char **my_argv = argv + 1;
+	struct lttng_condition *condition = NULL;
+	struct lttng_dynamic_pointer_array actions;
+	struct argpar_state *argpar_state = NULL;
+	struct argpar_item *argpar_item = NULL;
+	struct lttng_action *action_group = NULL;
+	struct lttng_action *action = NULL;
+	struct lttng_trigger *trigger = NULL;
+	char *error = NULL;
+	char *id = NULL;
+	int i;
+	char *fire_once_after_str = NULL;
+	char *fire_every_str = NULL;
+	char *user_id = NULL;
+
+	lttng_dynamic_pointer_array_init(&actions, lttng_actions_destructor);
+
+	while (true) {
+		enum argpar_state_parse_next_status status;
+		struct argpar_item_opt *item_opt;
+		int ingested_args;
+
+		argpar_state_destroy(argpar_state);
+		argpar_state = argpar_state_create(my_argc, my_argv,
+			add_trigger_options);
+		if (!argpar_state) {
+			ERR("Failed to create argpar state.");
+			goto error;
+		}
+
+		status = argpar_state_parse_next(argpar_state, &argpar_item, &error);
+
+		if (status == ARGPAR_STATE_PARSE_NEXT_STATUS_ERROR) {
+			ERR("%s", error);
+			goto error;
+		} else if (status == ARGPAR_STATE_PARSE_NEXT_STATUS_ERROR_UNKNOWN_OPT) {
+			ERR("%s", error);
+			goto error;
+		} else if (status == ARGPAR_STATE_PARSE_NEXT_STATUS_END) {
+			break;
+		}
+
+		assert(status == ARGPAR_STATE_PARSE_NEXT_STATUS_OK);
+
+		if (argpar_item->type == ARGPAR_ITEM_TYPE_NON_OPT) {
+			struct argpar_item_non_opt *item_non_opt =
+				(struct argpar_item_non_opt *) argpar_item;
+
+			ERR("Unexpected argument `%s`.",
+				item_non_opt->arg);
+			goto error;
+		}
+
+		item_opt = (struct argpar_item_opt *) argpar_item;
+
+		ingested_args = argpar_state_get_ingested_orig_args(
+			argpar_state);
+
+		my_argc -= ingested_args;
+		my_argv += ingested_args;
+
+		switch (item_opt->descr->id) {
+		case OPT_HELP:
+			SHOW_HELP();
+			ret = 0;
+			goto end;
+
+		case OPT_LIST_OPTIONS:
+			list_cmd_options_argpar(stdout, add_trigger_options);
+			ret = 0;
+			goto end;
+
+		case OPT_CONDITION:
+		{
+			if (condition) {
+				ERR("A --condition was already given.");
+				goto error;
+			}
+
+			condition = parse_condition(&my_argc, &my_argv);
+			if (!condition) {
+				/*
+				 * An error message was already printed by
+				 * parse_condition.
+				 */
+				goto error;
+			}
+
+			break;
+		}
+
+		case OPT_ACTION:
+		{
+			action = parse_action(&my_argc, &my_argv);
+			if (!action) {
+				/*
+				 * An error message was already printed by
+				 * parse_condition.
+				 */
+				goto error;
+			}
+
+			ret = lttng_dynamic_pointer_array_add_pointer(
+				&actions, action);
+			if (ret) {
+				ERR("Failed to add pointer to pointer array.");
+				goto error;
+			}
+
+			/* Ownership of the action was transferred to the group. */
+			action = NULL;
+
+			break;
+		}
+
+		case OPT_ID:
+		{
+			if (!assign_string(&id, item_opt->arg, "--id")) {
+				goto error;
+			}
+
+			break;
+		}
+
+		case OPT_FIRE_ONCE_AFTER:
+		{
+			if (!assign_string(&fire_once_after_str, item_opt->arg,
+					"--fire-once-after")) {
+				goto error;
+			}
+			break;
+		}
+
+		case OPT_FIRE_EVERY:
+		{
+			if (!assign_string(&fire_every_str, item_opt->arg,
+					"--fire-every")) {
+				goto error;
+			}
+			break;
+		}
+
+		case OPT_USER_ID:
+		{
+			if (!assign_string(&user_id, item_opt->arg,
+					"--user-id")) {
+				goto error;
+			}
+			break;
+		}
+
+		default:
+			abort();
+		}
+	}
+
+	if (!condition) {
+		ERR("Missing --condition.");
+		goto error;
+	}
+
+	if (lttng_dynamic_pointer_array_get_count(&actions) == 0) {
+		ERR("Need at least one --action.");
+		goto error;
+	}
+
+	if (fire_every_str && fire_once_after_str) {
+		ERR("Can't specify both --fire-once-after and --fire-every.");
+		goto error;
+	}
+
+	action_group = lttng_action_group_create();
+	if (!action_group) {
+		goto error;
+	}
+
+	for (i = 0; i < lttng_dynamic_pointer_array_get_count(&actions); i++) {
+		enum lttng_action_status status;
+
+		action = lttng_dynamic_pointer_array_steal_pointer(&actions, i);
+
+		status = lttng_action_group_add_action(
+			action_group, action);
+		if (status != LTTNG_ACTION_STATUS_OK) {
+			goto error;
+		}
+
+		/* Ownership of the action was transferred to the group. */
+		action = NULL;
+	}
+
+
+	trigger = lttng_trigger_create(condition, action_group);
+	if (!trigger) {
+		goto error;
+	}
+
+	if (id) {
+		enum lttng_trigger_status trigger_status =
+			lttng_trigger_set_name(trigger, id);
+		if (trigger_status != LTTNG_TRIGGER_STATUS_OK) {
+			ERR("Failed to set trigger id.");
+			goto error;
+		}
+	}
+
+	if (fire_once_after_str) {
+		unsigned long long threshold;
+		enum lttng_trigger_status trigger_status;
+
+		if (utils_parse_unsigned_long_long(fire_once_after_str, &threshold) != 0) {
+			ERR("Failed to parse `%s` as an integer.", fire_once_after_str);
+			goto error;
+		}
+
+		trigger_status = lttng_trigger_set_firing_policy(trigger,
+			LTTNG_TRIGGER_FIRE_ONCE_AFTER_N, threshold);
+		if (trigger_status != LTTNG_TRIGGER_STATUS_OK) {
+			ERR("Failed to set trigger's firing policy.");
+			goto error;
+		}
+	}
+
+	if (fire_every_str) {
+		unsigned long long threshold;
+		enum lttng_trigger_status trigger_status;
+
+		if (utils_parse_unsigned_long_long(fire_every_str, &threshold) != 0) {
+			ERR("Failed to parse `%s` as an integer.", fire_every_str);
+			goto error;
+		}
+
+		trigger_status = lttng_trigger_set_firing_policy(trigger,
+			LTTNG_TRIGGER_FIRE_EVERY_N, threshold);
+		if (trigger_status != LTTNG_TRIGGER_STATUS_OK) {
+			ERR("Failed to set trigger's firing policy.");
+			goto error;
+		}
+	}
+
+	if (user_id) {
+		enum lttng_trigger_status trigger_status;
+		char *end;
+		long long uid;
+
+		errno = 0;
+		uid = strtol(user_id, &end, 10);
+		if (end == user_id || *end != '\0' || errno != 0) {
+			ERR("Failed to parse `%s` as an integer.", user_id);
+		}
+
+		trigger_status = lttng_trigger_set_user_identity(trigger,
+			uid);
+		if (trigger_status != LTTNG_TRIGGER_STATUS_OK) {
+			ERR("Failed to set trigger's user identity.");
+			goto error;
+		}
+	}
+
+	ret = lttng_register_trigger(trigger);
+	if (ret) {
+		ERR("Failed to register trigger: %s.",
+			lttng_strerror(ret));
+		goto error;
+	}
+
+	MSG("Trigger registered successfully.");
+
+	goto end;
+
+error:
+	ret = 1;
+
+end:
+	argpar_state_destroy(argpar_state);
+	lttng_dynamic_pointer_array_reset(&actions);
+	lttng_condition_destroy(condition);
+	lttng_action_destroy(action_group);
+	lttng_trigger_destroy(trigger);
+	free(id);
+	free(fire_once_after_str);
+	free(fire_every_str);
+	free(user_id);
+	// TODO: check what else to free
+
+	return ret;
+}