Fix return code to 0 on success and 1 on error

[lttng-tools.git] / libustctl / libustctl.c

/*
 * Copyright (C) 2009  Pierre-Marc Fournier, Philippe Proulx-Barrette
 * Copyright (C) 2011  Ericsson AB
 *                     David Goulet <david.goulet@polymtl.ca>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
 */

#define _GNU_SOURCE
#include <dirent.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "libustcomm.h"
#include "libustctl.h"
#include "lttngerr.h"

/*
 *  do_cmd
 *
 *  Execute command using ustcomm API.
 */
static int do_cmd(int sock, const struct ustcomm_header *req_header,
		const char *req_data, struct ustcomm_header *res_header, char **res_data)
{
	int result, saved_errno = 0;
	char *recv_buf;

	recv_buf = malloc(USTCOMM_BUFFER_SIZE);
	if (!recv_buf) {
		saved_errno = ENOMEM;
		goto out;
	}

	result = ustcomm_req(sock, req_header, req_data, res_header, recv_buf);
	if (result > 0) {
		saved_errno = -res_header->result;
		if (res_header->size == 0 || saved_errno > 0) {
			free(recv_buf);
		} else {
			if (res_data) {
				*res_data = recv_buf;
			} else {
				free(recv_buf);
			}
		}
	} else {
		ERR("ustcomm req failed");
		if (result == 0) {
			saved_errno = ENOTCONN;
		} else {
			saved_errno = -result;
		}
		free(recv_buf);
	}

out:
	errno = saved_errno;
	if (errno) {
		return -1;
	}

	return 0;
}

/*
 *  realloc_pid_list
 */
static int realloc_pid_list(pid_t **pid_list, unsigned int *pid_list_size)
{
	pid_t *new_pid_list;
	unsigned int new_pid_list_size = 2 * (*pid_list_size);

	new_pid_list = realloc(*pid_list, new_pid_list_size * sizeof(pid_t));
	if (!*new_pid_list) {
		return -1;
	}

	*pid_list = new_pid_list;
	*pid_list_size = new_pid_list_size;

	return 0;
}

/*
 *  get_pids_in_dir
 *
 *  Set pid_list with all pid in the dir.
 */
static int get_pids_in_dir(DIR *dir, pid_t **pid_list,
		unsigned int *pid_list_index, unsigned int *pid_list_size)
{
	struct dirent *dirent;
	pid_t read_pid;

	while ((dirent = readdir(dir))) {
		if (!strcmp(dirent->d_name, ".") ||
			!strcmp(dirent->d_name, "..") ||
			!strcmp(dirent->d_name, "ust-consumer") ||
			dirent->d_type == DT_DIR) {
			continue;
		}

		if (ustcomm_is_socket_live(dirent->d_name, &read_pid)) {
			(*pid_list)[(*pid_list_index)++] = (long) read_pid;
			if (*pid_list_index == *pid_list_size) {
				if (realloc_pid_list(pid_list, pid_list_size)) {
					return -1;
				}
			}
		}
	}

	(*pid_list)[*pid_list_index] = 0; /* Array end */

	return 0;
}

/*
 *  get_pids_non_root
 */
static pid_t *get_pids_non_root(void)
{
	char *dir_name;
	DIR *dir;
	unsigned int pid_list_index = 0, pid_list_size = 1;
	pid_t *pid_list = NULL;

	dir_name = ustcomm_user_sock_dir();
	if (!dir_name) {
		return NULL;
	}

	dir = opendir(dir_name);
	if (!dir) {
		goto free_dir_name;
	}

	pid_list = malloc(pid_list_size * sizeof(pid_t));
	if (!pid_list) {
		goto close_dir;
	}

	if (get_pids_in_dir(dir, &pid_list, &pid_list_index, &pid_list_size)) {
		/* if any errors are encountered, force freeing of the list */
		pid_list[0] = 0;
	}

close_dir:
	closedir(dir);

free_dir_name:
	free(dir_name);

	return pid_list;
}

/*
 *  get_pids_root
 */
static pid_t *get_pids_root(void)
{
	char *dir_name;
	DIR *tmp_dir, *dir;
	unsigned int pid_list_index = 0, pid_list_size = 1;
	pid_t *pid_list = NULL;
	struct dirent *dirent;
	int result;

	tmp_dir = opendir(USER_TMP_DIR);
	if (!tmp_dir) {
		return NULL;
	}

	pid_list = malloc(pid_list_size * sizeof(pid_t));
	if (!pid_list) {
		goto close_tmp_dir;
	}

	while ((dirent = readdir(tmp_dir))) {
		/* Compare the dir to check for the USER_SOCK_DIR_BASE prefix */
		if (!strncmp(dirent->d_name, USER_SOCK_DIR_BASE,
					strlen(USER_SOCK_DIR_BASE))) {
			if (asprintf(&dir_name, USER_TMP_DIR "/%s", dirent->d_name) < 0) {
				goto close_tmp_dir;
			}

			dir = opendir(dir_name);
			free(dir_name);
			if (!dir) {
				continue;
			}

			result = get_pids_in_dir(dir, &pid_list, &pid_list_index, &pid_list_size);
			closedir(dir);
			if (result) {
				/*
				 * if any errors are encountered,
				 * force freeing of the list
				 */
				pid_list[0] = 0;
				break;
			}
		}
	}

close_tmp_dir:
	closedir(tmp_dir);
	return pid_list;
}

/*
 *  ustctl_get_subbuf_num_size
 */
static int ustctl_get_subbuf_num_size(int sock, const char *trace,
		const char *channel, int *num, int *size)
{
	struct ustcomm_header req_header, res_header;
	struct ustcomm_channel_info ch_inf, *ch_inf_res;
	int result;


	result = ustcomm_pack_channel_info(&req_header,
			&ch_inf, trace, channel);
	if (result < 0) {
		errno = -result;
		return -1;
	}

	req_header.command = GET_SUBBUF_NUM_SIZE;

	result = do_cmd(sock, &req_header, (char *)&ch_inf,
			&res_header, (char **)&ch_inf_res);
	if (result < 0) {
		return -1;
	}

	*num = ch_inf_res->subbuf_num;
	*size = ch_inf_res->subbuf_size;

	free(ch_inf_res);

	return 0;
}

/*
 *  do_trace_cmd
 *
 *  Do all trace action command
 */
static int do_trace_cmd(int sock, const char *trace, int command)
{
	struct ustcomm_header req_header, res_header;
	struct ustcomm_single_field trace_inf;
	int result;

	result = ustcomm_pack_single_field(&req_header, &trace_inf, trace);
	if (result < 0) {
		errno = -result;
		return -1;
	}

	req_header.command = command;

	return do_cmd(sock, &req_header, (char *)&trace_inf, &res_header, NULL);
}

/*
 *  ustctl_connect_pid
 *
 *  Connect to PID
 */
int ustctl_connect_pid(pid_t pid)
{
	int sock;

	if (ustcomm_connect_app(pid, &sock)) {
		ERR("could not connect to PID %u", (unsigned int) pid);
		errno = ENOTCONN;
		return -1;
	}

	return sock;
}

/*
 *  ustctl_get_online_pids
 *
 *  Return list of online pids.
 */
pid_t *ustctl_get_online_pids(void)
{
	pid_t *pid_list;

	if (geteuid()) {
		pid_list = get_pids_non_root();
	} else {
		pid_list = get_pids_root();
	}

	if (pid_list && pid_list[0] == 0) {
		/* No PID at all */
		free(pid_list);
		pid_list = NULL;
	}

	return pid_list;
}

/*
 * Sets ust_marker state (USTCTL_MS_ON or USTCTL_MS_OFF).
 *
 * @param mn	Marker name
 * @param state	Marker's new state
 * @param pid	Traced process ID
 * @return	0 if successful, or errors {USTCTL_ERR_GEN, USTCTL_ERR_ARG}
 */
int ustctl_set_marker_state(int sock, const char *trace, const char *channel,
		const char *ust_marker, int state)
{
	struct ustcomm_header req_header, res_header;
	struct ustcomm_ust_marker_info ust_marker_inf;
	int result;

	result = ustcomm_pack_ust_marker_info(&req_header, &ust_marker_inf,
					trace, channel, ust_marker);
	if (result < 0) {
		errno = -result;
		return -1;
	}

	req_header.command = state ? ENABLE_MARKER : DISABLE_MARKER;

	return do_cmd(sock, &req_header, (char *)&ust_marker_inf, &res_header, NULL);
}

/*
 * Set subbuffer size.
 *
 * @param channel_size	Channel name and size
 * @param pid		Traced process ID
 * @return		0 if successful, or error
 */
int ustctl_set_subbuf_size(int sock, const char *trace, const char *channel,
		unsigned int subbuf_size)
{
	struct ustcomm_header req_header, res_header;
	struct ustcomm_channel_info ch_inf;
	int result;

	result = ustcomm_pack_channel_info(&req_header, &ch_inf,
					trace, channel);
	if (result < 0) {
		errno = -result;
		return -1;
	}

	req_header.command = SET_SUBBUF_SIZE;
	ch_inf.subbuf_size = subbuf_size;

	return do_cmd(sock, &req_header, (char *)&ch_inf, &res_header, NULL);
}

/*
 * Set subbuffer num.
 *
 * @param channel_num	Channel name and num
 * @param pid		Traced process ID
 * @return		0 if successful, or error
 */
int ustctl_set_subbuf_num(int sock, const char *trace, const char *channel,
		unsigned int num)
{
	struct ustcomm_header req_header, res_header;
	struct ustcomm_channel_info ch_inf;
	int result;

	result = ustcomm_pack_channel_info(&req_header,
					&ch_inf, trace, channel);
	if (result < 0) {
		errno = -result;
		return -1;
	}

	req_header.command = SET_SUBBUF_NUM;
	ch_inf.subbuf_num = num;

	return do_cmd(sock, &req_header, (char *)&ch_inf, &res_header, NULL);

}

/*
 * Get subbuffer num.
 *
 * @param channel	Channel name
 * @param pid		Traced process ID
 * @return		subbuf cnf if successful, or error
 */
int ustctl_get_subbuf_num(int sock, const char *trace, const char *channel)
{
	int num, size, result;

	result = ustctl_get_subbuf_num_size(sock, trace, channel, &num, &size);
	if (result < 0) {
		errno = -result;
		return -1;
	}

	return num;
}

/*
 * Get subbuffer size.
 *
 * @param channel	Channel name
 * @param pid		Traced process ID
 * @return		subbuf size if successful, or error
 */
int ustctl_get_subbuf_size(int sock, const char *trace, const char *channel)
{
	int num, size, result;

	result = ustctl_get_subbuf_num_size(sock, trace, channel, &num, &size);
	if (result < 0) {
		errno = -result;
		return -1;
	}

	return size;
}

/*
 * Destroys an UST trace according to a PID.
 *
 * @param pid	Traced process ID
 * @return	0 if successful, or error USTCTL_ERR_GEN
 */
int ustctl_destroy_trace(int sock, const char *trace)
{
	return do_trace_cmd(sock, trace, DESTROY_TRACE);
}

/*
 * Starts an UST trace (and setups it) according to a PID.
 *
 * @param pid	Traced process ID
 * @return	0 if successful, or error USTCTL_ERR_GEN
 */
int ustctl_setup_and_start(int sock, const char *trace)
{
	return do_trace_cmd(sock, trace, START);
}

/*
 * Creates an UST trace according to a PID.
 *
 * @param pid	Traced process ID
 * @return	0 if successful, or error USTCTL_ERR_GEN
 */
int ustctl_create_trace(int sock, const char *trace)
{
	return do_trace_cmd(sock, trace, CREATE_TRACE);
}

/*
 * Starts an UST trace according to a PID.
 *
 * @param pid	Traced process ID
 * @return	0 if successful, or error USTCTL_ERR_GEN
 */
int ustctl_start_trace(int sock, const char *trace)
{
	return do_trace_cmd(sock, trace, START_TRACE);
}

/*
 * Alloc an UST trace according to a PID.
 *
 * @param pid	Traced process ID
 * @return	0 if successful, or error USTCTL_ERR_GEN
 */
int ustctl_alloc_trace(int sock, const char *trace)
{
	return do_trace_cmd(sock, trace, ALLOC_TRACE);
}

/*
 *  ustctl_force_switch
 *
 *  Force switch buffer in libust
 */
int ustctl_force_switch(int sock, const char *trace)
{
	return do_trace_cmd(sock, trace, FORCE_SUBBUF_SWITCH);
}

/*
 * Stops an UST trace according to a PID.
 *
 * @param pid	Traced process ID
 * @return	0 if successful, or error USTCTL_ERR_GEN
 */
int ustctl_stop_trace(int sock, const char *trace)
{
	return do_trace_cmd(sock, trace, STOP_TRACE);
}

/*
 * Counts newlines ('\n') in a string.
 *
 * @param str	String to search in
 * @return	Total newlines count
 */
unsigned int ustctl_count_nl(const char *str)
{
	unsigned int i = 0, tot = 0;

	while (str[i] != '\0') {
		if (str[i] == '\n') {
			++tot;
		}
		++i;
	}

	return tot;
}

/*
 * Frees a CMSF array.
 *
 * @param cmsf	CMSF array to free
 * @return	0 if successful, or error USTCTL_ERR_ARG
 */
int ustctl_free_cmsf(struct ustctl_marker_status *cmsf)
{
	if (cmsf == NULL) {
		return -1;
	}

	unsigned int i = 0;
	while (cmsf[i].channel != NULL) {
		free(cmsf[i].channel);
		free(cmsf[i].ust_marker);
		free(cmsf[i].fs);
		++i;
	}
	free(cmsf);

	return 0;
}

/*
 * Gets channel/ust_marker/state/format string for a given PID.
 *
 * @param cmsf	Pointer to CMSF array to be filled (callee allocates, caller
 *		frees with `ustctl_free_cmsf')
 * @param pid	Targeted PID
 * @return	0 if successful, or -1 on error
 */
int ustctl_get_cmsf(int sock, struct ustctl_marker_status **cmsf)
{
	struct ustcomm_header req_header, res_header;
	char *big_str = NULL;
	int result;
	struct ustctl_marker_status *tmp_cmsf = NULL;
	unsigned int i = 0, cmsf_ind = 0;

	if (cmsf == NULL) {
		return -1;
	}

	req_header.command = LIST_MARKERS;
	req_header.size = 0;

	result = ustcomm_send(sock, &req_header, NULL);
	if (result <= 0) {
		ERR("error while requesting ust_marker list");
		return -1;
	}

	result = ustcomm_recv_alloc(sock, &res_header, &big_str);
	if (result <= 0) {
		ERR("error while receiving ust_marker list");
		return -1;
	}

	tmp_cmsf = (struct ustctl_marker_status *) malloc(sizeof(struct ustctl_marker_status) *
						(ustctl_count_nl(big_str) + 1));
	if (tmp_cmsf == NULL) {
		ERR("Failed to allocate CMSF array");
		return -1;
	}

	/* Parse received reply string (format: "[chan]/[mark] [st] [fs]"): */
	while (big_str[i] != '\0') {
		char state;

		sscanf(big_str + i, "ust_marker: %a[^/]/%a[^ ] %c %a[^\n]",
				&tmp_cmsf[cmsf_ind].channel,
				&tmp_cmsf[cmsf_ind].ust_marker,
				&state,
				&tmp_cmsf[cmsf_ind].fs);
		tmp_cmsf[cmsf_ind].state = (state == USTCTL_MS_CHR_ON ?
						USTCTL_MS_ON : USTCTL_MS_OFF); /* Marker state */

		while (big_str[i] != '\n') {
			++i; /* Go to next '\n' */
		}
		++i; /* Skip current pointed '\n' */
		++cmsf_ind;
	}
	tmp_cmsf[cmsf_ind].channel = NULL;
	tmp_cmsf[cmsf_ind].ust_marker = NULL;
	tmp_cmsf[cmsf_ind].fs = NULL;

	*cmsf = tmp_cmsf;

	free(big_str);
	return 0;
}

/*
 * Frees a TES array.
 *
 * @param tes	TES array to free
 * @return	0 if successful, or error USTCTL_ERR_ARG
 */
int ustctl_free_tes(struct ustctl_trace_event_status *tes)
{
	if (tes == NULL) {
		return USTCTL_ERR_ARG;
	}

	unsigned int i = 0;
	while (tes[i].name != NULL) {
		free(tes[i].name);
		++i;
	}
	free(tes);

	return 0;
}

/*
 * Gets trace_events string for a given PID.
 *
 * @param tes	Pointer to TES array to be filled (callee allocates, caller
 *		frees with `ustctl_free_tes')
 * @param pid	Targeted PID
 * @return	0 if successful, or -1 on error
 */
int ustctl_get_tes(int sock, struct ustctl_trace_event_status **tes)
{
	struct ustcomm_header req_header, res_header;
	char *big_str = NULL;
	int result;
	struct ustctl_trace_event_status *tmp_tes = NULL;
	unsigned int i = 0, tes_ind = 0;

	if (tes == NULL) {
		return -1;
	}

	req_header.command = LIST_TRACE_EVENTS;
	req_header.size = 0;

	result = ustcomm_send(sock, &req_header, NULL);
	if (result != 1) {
		ERR("error while requesting trace_event list");
		return -1;
	}

	result = ustcomm_recv_alloc(sock, &res_header, &big_str);
	if (result != 1) {
		ERR("error while receiving ust_marker list");
		return -1;
	}

	tmp_tes = (struct ustctl_trace_event_status *)
		malloc(sizeof(struct ustctl_trace_event_status) *
			(ustctl_count_nl(big_str) + 1));
	if (tmp_tes == NULL) {
		ERR("Failed to allocate TES array");
		return -1;
	}

	/* Parse received reply string (format: "[name]"): */
	while (big_str[i] != '\0') {
		sscanf(big_str + i, "trace_event: %a[^\n]", &tmp_tes[tes_ind].name);
		while (big_str[i] != '\n') {
			++i; /* Go to next '\n' */
		}
		++i; /* Skip current pointed '\n' */
		++tes_ind;
	}
	tmp_tes[tes_ind].name = NULL;

	*tes = tmp_tes;

	free(big_str);
	return 0;
}

/*
 * Set sock path
 *
 * @param sock_path	Sock path
 * @param pid		Traced process ID
 * @return		0 if successful, or error
 */
int ustctl_set_sock_path(int sock, const char *sock_path)
{
	int result;
	struct ustcomm_header req_header, res_header;
	struct ustcomm_single_field sock_path_msg;

	result = ustcomm_pack_single_field(&req_header, &sock_path_msg, sock_path);
	if (result < 0) {
		errno = -result;
		return -1;
	}

	req_header.command = SET_SOCK_PATH;

	return do_cmd(sock, &req_header, (char *)&sock_path_msg, &res_header, NULL);
}

/*
 * Get sock path
 *
 * @param sock_path	Pointer to where the sock path will be returned
 * @param pid		Traced process ID
 * @return		0 if successful, or error
 */
int ustctl_get_sock_path(int sock, char **sock_path)
{
	int result;
	struct ustcomm_header req_header, res_header;
	struct ustcomm_single_field *sock_path_msg;

	req_header.command = GET_SOCK_PATH;
	req_header.size = 0;

	result = do_cmd(sock, &req_header, NULL, &res_header,
			(char **)&sock_path_msg);
	if (result < 0) {
		return -1;
	}

	result = ustcomm_unpack_single_field(sock_path_msg);
	if (result < 0) {
		return result;
	}

	*sock_path = strdup(sock_path_msg->field);

	free(sock_path_msg);

	return 0;
}