Fix: invalid discarded events on start/stop without event production

[lttng-tools.git] / src / common / context.c

/*
 * Copyright (C) 2016 Jérémie Galarneau <jeremie.galarneau@efficios.com>
 *
 * SPDX-License-Identifier: LGPL-2.1-only
 *
 */

#include "context.h"
#include <stddef.h>
#include <string.h>
#include <common/error.h>
#include <common/macros.h>

LTTNG_HIDDEN
int parse_application_context(const char *str, char **out_provider_name,
		char **out_ctx_name)
{
	const char app_ctx_prefix[] = "$app.";
	char *provider_name = NULL, *ctx_name = NULL;
	size_t i, len, colon_pos = 0, provider_name_len, ctx_name_len;

	if (!str || !out_provider_name || !out_ctx_name) {
		goto not_found;
	}

	len = strlen(str);
	if (len <= sizeof(app_ctx_prefix) - 1) {
		goto not_found;
	}

	/* String starts with $app. */
	if (strncmp(str, app_ctx_prefix, sizeof(app_ctx_prefix) - 1)) {
		goto not_found;
	}

	/* Validate that the ':' separator is present. */
	for (i = sizeof(app_ctx_prefix); i < len; i++) {
		const char c = str[i];

		if (c == ':') {
			colon_pos = i;
			break;
		}
	}

	/*
	 * No colon found or no ctx name ("$app.provider:") or no provider name
	 * given ("$app.:..."), which is invalid.
	 */
	if (!colon_pos || colon_pos == len ||
			colon_pos == sizeof(app_ctx_prefix)) {
		goto not_found;
	}

	provider_name_len = colon_pos - sizeof(app_ctx_prefix) + 2;
	provider_name = zmalloc(provider_name_len);
	if (!provider_name) {
		PERROR("malloc provider_name");
		goto not_found;
	}
	strncpy(provider_name, str + sizeof(app_ctx_prefix) - 1,
			provider_name_len - 1);

	ctx_name_len = len - colon_pos;
	ctx_name = zmalloc(ctx_name_len);
	if (!ctx_name) {
		PERROR("malloc ctx_name");
		goto not_found;
	}
	strncpy(ctx_name, str + colon_pos + 1, ctx_name_len - 1);

	*out_provider_name = provider_name;
	*out_ctx_name = ctx_name;
	return 0;
not_found:
	free(provider_name);
	free(ctx_name);
	return -1;
}