[lttng-tools.git] / liblttng-sessiond-comm / lttng-sessiond-comm.c

/*
 * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
 *                      Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation; only version 2 of the License.
 * 
 * This program 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 General Public License for
 * more details.
 * 
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
 * Place - Suite 330, Boston, MA  02111-1307, USA.
 */

#define _GNU_SOURCE
#include <assert.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/un.h>
#include <unistd.h>
#include <errno.h>

#include <lttng-sessiond-comm.h>

/*
 * Human readable error message.
 */
static const char *lttcomm_readable_code[] = {
	[ LTTCOMM_ERR_INDEX(LTTCOMM_OK) ] = "Success",
	[ LTTCOMM_ERR_INDEX(LTTCOMM_ERR) ] = "Unknown error",
	[ LTTCOMM_ERR_INDEX(LTTCOMM_UND) ] = "Undefined command",
	[ LTTCOMM_ERR_INDEX(LTTCOMM_NOT_IMPLEMENTED) ] = "Not implemented",
	[ LTTCOMM_ERR_INDEX(LTTCOMM_UNKNOWN_DOMAIN) ] = "Unknown tracing domain",
	[ LTTCOMM_ERR_INDEX(LTTCOMM_NO_SESSION) ] = "No session found",
	[ LTTCOMM_ERR_INDEX(LTTCOMM_LIST_FAIL) ] = "Unable to list traceable apps",
	[ LTTCOMM_ERR_INDEX(LTTCOMM_NO_APPS) ] = "No traceable apps found",
	[ LTTCOMM_ERR_INDEX(LTTCOMM_SESS_NOT_FOUND) ] = "Session name not found",
	[ LTTCOMM_ERR_INDEX(LTTCOMM_NO_TRACE) ] = "No trace found",
	[ LTTCOMM_ERR_INDEX(LTTCOMM_FATAL) ] = "Fatal error of the session daemon",
	[ LTTCOMM_ERR_INDEX(LTTCOMM_CREATE_FAIL) ] = "Create trace failed",
	[ LTTCOMM_ERR_INDEX(LTTCOMM_START_FAIL) ] = "Start trace failed",
	[ LTTCOMM_ERR_INDEX(LTTCOMM_STOP_FAIL) ] = "Stop trace failed",
	[ LTTCOMM_ERR_INDEX(LTTCOMM_NO_TRACEABLE) ] = "App is not traceable",
	[ LTTCOMM_ERR_INDEX(LTTCOMM_SELECT_SESS) ] = "A session MUST be selected",
	[ LTTCOMM_ERR_INDEX(LTTCOMM_EXIST_SESS) ] = "Session name already exist",
	[ LTTCOMM_ERR_INDEX(LTTCOMM_CONNECT_FAIL) ] = "Unable to connect to Unix socket",
	[ LTTCOMM_ERR_INDEX(LTTCOMM_APP_NOT_FOUND) ] = "Application not found",
	[ LTTCOMM_ERR_INDEX(LTTCOMM_EPERM) ] = "Permission denied",
	[ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_NA) ] = "Kernel tracer not available",
	[ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_EVENT_EXIST) ] = "Kernel event already exists",
	[ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_SESS_FAIL) ] = "Kernel create session failed",
	[ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CHAN_FAIL) ] = "Kernel create channel failed",
	[ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CHAN_NOT_FOUND) ] = "Kernel channel not found",
	[ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CHAN_DISABLE_FAIL) ] = "Disable kernel channel failed",
	[ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CHAN_ENABLE_FAIL) ] = "Enable kernel channel failed",
	[ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CONTEXT_FAIL) ] = "Add kernel context failed",
	[ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_ENABLE_FAIL) ] = "Enable kernel event failed",
	[ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_DISABLE_FAIL) ] = "Disable kernel event failed",
	[ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_META_FAIL) ] = "Opening metadata failed",
	[ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_START_FAIL) ] = "Starting kernel trace failed",
	[ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_STOP_FAIL) ] = "Stoping kernel trace failed",
	[ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CONSUMER_FAIL) ] = "Kernel consumer start failed",
	[ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_STREAM_FAIL) ] = "Kernel create stream failed",
	[ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_DIR_FAIL) ] = "Kernel trace directory creation failed",
	[ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_DIR_EXIST) ] = "Kernel trace directory already exist",
	[ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_NO_SESSION) ] = "No kernel session found",
	[ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_LIST_FAIL) ] = "Listing kernel events failed",
	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_SESS_FAIL) ] = "UST create session failed",
	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CHAN_FAIL) ] = "UST create channel failed",
	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CHAN_EXIST) ] = "UST channel already exist",
	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CHAN_NOT_FOUND) ] = "UST channel not found",
	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CHAN_DISABLE_FAIL) ] = "Disable UST channel failed",
	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CHAN_ENABLE_FAIL) ] = "Enable UST channel failed",
	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CONTEXT_FAIL) ] = "Add UST context failed",
	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_ENABLE_FAIL) ] = "Enable UST event failed",
	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_DISABLE_FAIL) ] = "Disable UST event failed",
	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_META_FAIL) ] = "Opening metadata failed",
	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_START_FAIL) ] = "Starting UST trace failed",
	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_STOP_FAIL) ] = "Stoping UST trace failed",
	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CONSUMER64_FAIL) ] = "64-bit UST consumer start failed",
	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CONSUMER32_FAIL) ] = "32-bit UST consumer start failed",
	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_STREAM_FAIL) ] = "UST create stream failed",
	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_DIR_FAIL) ] = "UST trace directory creation failed",
	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_DIR_EXIST) ] = "UST trace directory already exist",
	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_NO_SESSION) ] = "No UST session found",
	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_LIST_FAIL) ] = "Listing UST events failed",
	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_EVENT_EXIST) ] = "UST event already exist",
	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_EVENT_NOT_FOUND)] = "UST event not found",
	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CONTEXT_EXIST)] = "UST context already exist",
	[ LTTCOMM_ERR_INDEX(CONSUMERD_COMMAND_SOCK_READY) ] = "consumerd command socket ready",
	[ LTTCOMM_ERR_INDEX(CONSUMERD_SUCCESS_RECV_FD) ] = "consumerd success on receiving fds",
	[ LTTCOMM_ERR_INDEX(CONSUMERD_ERROR_RECV_FD) ] = "consumerd error on receiving fds",
	[ LTTCOMM_ERR_INDEX(CONSUMERD_ERROR_RECV_CMD) ] = "consumerd error on receiving command",
	[ LTTCOMM_ERR_INDEX(CONSUMERD_POLL_ERROR) ] = "consumerd error in polling thread",
	[ LTTCOMM_ERR_INDEX(CONSUMERD_POLL_NVAL) ] = "consumerd polling on closed fd",
	[ LTTCOMM_ERR_INDEX(CONSUMERD_POLL_HUP) ] = "consumerd all fd hung up",
	[ LTTCOMM_ERR_INDEX(CONSUMERD_EXIT_SUCCESS) ] = "consumerd exiting normally",
	[ LTTCOMM_ERR_INDEX(CONSUMERD_EXIT_FAILURE) ] = "consumerd exiting on error",
	[ LTTCOMM_ERR_INDEX(CONSUMERD_OUTFD_ERROR) ] = "consumerd error opening the tracefile",
	[ LTTCOMM_ERR_INDEX(CONSUMERD_SPLICE_EBADF) ] = "consumerd splice EBADF",
	[ LTTCOMM_ERR_INDEX(CONSUMERD_SPLICE_EINVAL) ] = "consumerd splice EINVAL",
	[ LTTCOMM_ERR_INDEX(CONSUMERD_SPLICE_ENOMEM) ] = "consumerd splice ENOMEM",
	[ LTTCOMM_ERR_INDEX(CONSUMERD_SPLICE_ESPIPE) ] = "consumerd splice ESPIPE",
	[ LTTCOMM_ERR_INDEX(LTTCOMM_NO_EVENT) ] = "Event not found",
};

/*
 * Return ptr to string representing a human readable error code from the
 * lttcomm_return_code enum.
 *
 * These code MUST be negative in other to treat that as an error value.
 */
const char *lttcomm_get_readable_code(enum lttcomm_return_code code)
{
	int tmp_code = -code;

	if (tmp_code >= LTTCOMM_OK && tmp_code < LTTCOMM_NR) {
		return lttcomm_readable_code[LTTCOMM_ERR_INDEX(tmp_code)];
	}

	return "Unknown error code";
}

/*
 * Connect to unix socket using the path name.
 */
int lttcomm_connect_unix_sock(const char *pathname)
{
	struct sockaddr_un sun;
	int fd;
	int ret;

	fd = socket(PF_UNIX, SOCK_STREAM, 0);
	if (fd < 0) {
		perror("socket");
		ret = fd;
		goto error;
	}

	memset(&sun, 0, sizeof(sun));
	sun.sun_family = AF_UNIX;
	strncpy(sun.sun_path, pathname, sizeof(sun.sun_path));
	sun.sun_path[sizeof(sun.sun_path) - 1] = '\0';

	ret = connect(fd, (struct sockaddr *) &sun, sizeof(sun));
	if (ret < 0) {
		/*
		 * Don't print message on connect error, because connect is used in
		 * normal execution to detect if sessiond is alive.
		 */
		goto error_connect;
	}

	return fd;

error_connect:
	close(fd);
error:
	return ret;
}

/*
 * Do an accept(2) on the sock and return the new file descriptor. The socket
 * MUST be bind(2) before.
 */
int lttcomm_accept_unix_sock(int sock)
{
	int new_fd;
	struct sockaddr_un sun;
	socklen_t len = 0;

	/* Blocking call */
	new_fd = accept(sock, (struct sockaddr *) &sun, &len);
	if (new_fd < 0) {
		perror("accept");
	}

	return new_fd;
}

/*
 * Creates a AF_UNIX local socket using pathname bind the socket upon creation
 * and return the fd.
 */
int lttcomm_create_unix_sock(const char *pathname)
{
	struct sockaddr_un sun;
	int fd;
	int ret = -1;

	/* Create server socket */
	if ((fd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0) {
		perror("socket");
		goto error;
	}

	memset(&sun, 0, sizeof(sun));
	sun.sun_family = AF_UNIX;
	strncpy(sun.sun_path, pathname, sizeof(sun.sun_path));
	sun.sun_path[sizeof(sun.sun_path) - 1] = '\0';

	/* Unlink the old file if present */
	(void) unlink(pathname);
	ret = bind(fd, (struct sockaddr *) &sun, sizeof(sun));
	if (ret < 0) {
		perror("bind");
		goto error;
	}

	return fd;

error:
	return ret;
}

/*
 * Make the socket listen using LTTNG_SESSIOND_COMM_MAX_LISTEN.
 */
int lttcomm_listen_unix_sock(int sock)
{
	int ret;

	ret = listen(sock, LTTNG_SESSIOND_COMM_MAX_LISTEN);
	if (ret < 0) {
		perror("listen");
	}

	return ret;
}

/*
 * Receive data of size len in put that data into the buf param. Using recvmsg
 * API.
 *
 * Return the size of received data.
 */
ssize_t lttcomm_recv_unix_sock(int sock, void *buf, size_t len)
{
	struct msghdr msg = { 0 };
	struct iovec iov[1];
	ssize_t ret = -1;

	iov[0].iov_base = buf;
	iov[0].iov_len = len;
	msg.msg_iov = iov;
	msg.msg_iovlen = 1;

	ret = recvmsg(sock, &msg, 0);
	if (ret < 0) {
		perror("recvmsg");
	}

	return ret;
}

/*
 * Send buf data of size len. Using sendmsg API.
 *
 * Return the size of sent data.
 */
ssize_t lttcomm_send_unix_sock(int sock, void *buf, size_t len)
{
	struct msghdr msg = { 0 };
	struct iovec iov[1];
	ssize_t ret = -1;

	iov[0].iov_base = buf;
	iov[0].iov_len = len;
	msg.msg_iov = iov;
	msg.msg_iovlen = 1;

	ret = sendmsg(sock, &msg, 0);
	if (ret < 0) {
		perror("sendmsg");
	}

	return ret;
}

/*
 * Shutdown cleanly a unix socket.
 */
int lttcomm_close_unix_sock(int sock)
{
	int ret;

	/* Shutdown receptions and transmissions */
	ret = shutdown(sock, SHUT_RDWR);
	if (ret < 0) {
		perror("shutdown");
	}

	return ret;
}

/*
 * Send a message accompanied by fd(s) over a unix socket.
 *
 * Returns the size of data sent, or negative error value.
 */
ssize_t lttcomm_send_fds_unix_sock(int sock, int *fds, size_t nb_fd)
{
	struct msghdr msg = { 0 };
	struct cmsghdr *cmptr;
	struct iovec iov[1];
	ssize_t ret = -1;
	unsigned int sizeof_fds = nb_fd * sizeof(int);
	char tmp[CMSG_SPACE(sizeof_fds)];
	char dummy = 0;

	if (nb_fd > LTTCOMM_MAX_SEND_FDS)
		return -EINVAL;

	msg.msg_control = (caddr_t)tmp;
	msg.msg_controllen = CMSG_LEN(sizeof_fds);

	cmptr = CMSG_FIRSTHDR(&msg);
	cmptr->cmsg_level = SOL_SOCKET;
	cmptr->cmsg_type = SCM_RIGHTS;
	cmptr->cmsg_len = CMSG_LEN(sizeof_fds);
	memcpy(CMSG_DATA(cmptr), fds, sizeof_fds);
	/* Sum of the length of all control messages in the buffer: */
	msg.msg_controllen = cmptr->cmsg_len;

	iov[0].iov_base = &dummy;
	iov[0].iov_len = 1;
	msg.msg_iov = iov;
	msg.msg_iovlen = 1;

	ret = sendmsg(sock, &msg, 0);
	if (ret < 0) {
		perror("sendmsg");
	}
	return ret;
}

/*
 * Recv a message accompanied by fd(s) from a unix socket.
 *
 * Returns the size of received data, or negative error value.
 *
 * Expect at most "nb_fd" file descriptors. Returns the number of fd
 * actually received in nb_fd.
 */
ssize_t lttcomm_recv_fds_unix_sock(int sock, int *fds, size_t nb_fd)
{
	struct iovec iov[1];
	ssize_t ret = 0;
	struct cmsghdr *cmsg;
	size_t sizeof_fds = nb_fd * sizeof(int);
	char recv_fd[CMSG_SPACE(sizeof_fds)];
	struct msghdr msg = { 0 };
	char dummy;

	/* Prepare to receive the structures */
	iov[0].iov_base = &dummy;
	iov[0].iov_len = 1;
	msg.msg_iov = iov;
	msg.msg_iovlen = 1;
	msg.msg_control = recv_fd;
	msg.msg_controllen = sizeof(recv_fd);

	ret = recvmsg(sock, &msg, 0);
	if (ret < 0) {
		perror("recvmsg fds");
		goto end;
	}
	if (ret != 1) {
		fprintf(stderr, "Error: Received %zd bytes, expected %d\n",
				ret, 1);
		goto end;
	}
	if (msg.msg_flags & MSG_CTRUNC) {
		fprintf(stderr, "Error: Control message truncated.\n");
		ret = -1;
		goto end;
	}
	cmsg = CMSG_FIRSTHDR(&msg);
	if (!cmsg) {
		fprintf(stderr, "Error: Invalid control message header\n");
		ret = -1;
		goto end;
	}
	if (cmsg->cmsg_level != SOL_SOCKET || cmsg->cmsg_type != SCM_RIGHTS) {
		fprintf(stderr, "Didn't received any fd\n");
		ret = -1;
		goto end;
	}
	if (cmsg->cmsg_len != CMSG_LEN(sizeof_fds)) {
		fprintf(stderr, "Error: Received %zu bytes of ancillary data, expected %zu\n",
				cmsg->cmsg_len, CMSG_LEN(sizeof_fds));
		ret = -1;
		goto end;
	}
	memcpy(fds, CMSG_DATA(cmsg), sizeof_fds);
	ret = sizeof_fds;
end:
	return ret;
}

/*
 * Send a message with credentials over a unix socket.
 *
 * Returns the size of data sent, or negative error value.
 */
ssize_t lttcomm_send_creds_unix_sock(int sock, void *buf, size_t len)
{
	struct msghdr msg = { 0 };
	struct cmsghdr *cmptr;
	struct iovec iov[1];
	ssize_t ret = -1;
	struct ucred *creds;
	size_t sizeof_cred = sizeof(struct ucred);
	char anc_buf[CMSG_SPACE(sizeof_cred)];

	iov[0].iov_base = buf;
	iov[0].iov_len = len;
	msg.msg_iov = iov;
	msg.msg_iovlen = 1;

	msg.msg_control = (caddr_t) anc_buf;
	msg.msg_controllen = CMSG_LEN(sizeof_cred);

	cmptr = CMSG_FIRSTHDR(&msg);
	cmptr->cmsg_level = SOL_SOCKET;
	cmptr->cmsg_type = SCM_CREDENTIALS;
	cmptr->cmsg_len = CMSG_LEN(sizeof_cred);

	creds = (struct ucred *) CMSG_DATA(cmptr);

	creds->uid = geteuid();
	creds->gid = getegid();
	creds->pid = getpid();

	ret = sendmsg(sock, &msg, 0);
	if (ret < 0) {
		perror("sendmsg");
	}

	return ret;
}

/*
 * Recv a message accompanied with credentials from a unix socket.
 *
 * Returns the size of received data, or negative error value.
 */
ssize_t lttcomm_recv_creds_unix_sock(int sock, void *buf, size_t len,
		struct ucred *creds)
{
	struct msghdr msg = { 0 };
	struct cmsghdr *cmptr;
	struct iovec iov[1];
	ssize_t ret;
	size_t sizeof_cred = sizeof(struct ucred);
	char anc_buf[CMSG_SPACE(sizeof_cred)];

	/* Not allowed */
	if (creds == NULL) {
		ret = -1;
		goto end;
	}

	/* Prepare to receive the structures */
	iov[0].iov_base = buf;
	iov[0].iov_len = len;
	msg.msg_iov = iov;
	msg.msg_iovlen = 1;

	msg.msg_control = anc_buf;
	msg.msg_controllen = sizeof(anc_buf);

	ret = recvmsg(sock, &msg, 0);
	if (ret < 0) {
		perror("recvmsg fds");
		goto end;
	}

	if (msg.msg_flags & MSG_CTRUNC) {
		fprintf(stderr, "Error: Control message truncated.\n");
		ret = -1;
		goto end;
	}

	cmptr = CMSG_FIRSTHDR(&msg);
	if (cmptr == NULL) {
		fprintf(stderr, "Error: Invalid control message header\n");
		ret = -1;
		goto end;
	}

	if (cmptr->cmsg_level != SOL_SOCKET ||
			cmptr->cmsg_type != SCM_CREDENTIALS) {
		fprintf(stderr, "Didn't received any credentials\n");
		ret = -1;
		goto end;
	}

	if (cmptr->cmsg_len != CMSG_LEN(sizeof_cred)) {
		fprintf(stderr, "Error: Received %zu bytes of ancillary data, expected %zu\n",
				cmptr->cmsg_len, CMSG_LEN(sizeof_cred));
		ret = -1;
		goto end;
	}

	memcpy(creds, CMSG_DATA(cmptr), sizeof_cred);

end:
	return ret;
}

/*
 * Set socket option to use credentials passing.
 */
int lttcomm_setsockopt_creds_unix_sock(int sock)
{
	int ret, on = 1;

	/* Set socket for credentials retrieval */
	ret = setsockopt(sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
	if (ret < 0) {
		perror("setsockopt creds unix sock");
	}

	return ret;
}
Commit	Line	Data
826d496d	1	/*
917216f6 DG	2	* Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
917216f6 DG	3	* Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
fac6795d	4	*
917216f6 DG	5	* This program is free software; you can redistribute it and/or modify it
	6	* under the terms of the GNU General Public License as published by the Free
	7	* Software Foundation; only version 2 of the License.
fac6795d	8	*
917216f6 DG	9	* This program is distributed in the hope that it will be useful, but WITHOUT
	10	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	11	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
	12	* more details.
fac6795d	13	*
917216f6 DG	14	* You should have received a copy of the GNU General Public License along with
	15	* this program; if not, write to the Free Software Foundation, Inc., 59 Temple
	16	* Place - Suite 330, Boston, MA 02111-1307, USA.
fac6795d DG	17	*/
	18
	19	#define _GNU_SOURCE
1e307fab	20	#include <assert.h>
fac6795d DG	21	#include <limits.h>
	22	#include <stdio.h>
	23	#include <stdlib.h>
	24	#include <string.h>
fac6795d DG	25	#include <sys/stat.h>
	26	#include <sys/types.h>
	27	#include <sys/un.h>
	28	#include <unistd.h>
3bd1e081	29	#include <errno.h>
fac6795d	30
e88129fc	31	#include <lttng-sessiond-comm.h>
fac6795d DG	32
	33	/*
	34	* Human readable error message.
	35	*/
	36	static const char *lttcomm_readable_code[] = {
	37	[ LTTCOMM_ERR_INDEX(LTTCOMM_OK) ] = "Success",
	38	[ LTTCOMM_ERR_INDEX(LTTCOMM_ERR) ] = "Unknown error",
	39	[ LTTCOMM_ERR_INDEX(LTTCOMM_UND) ] = "Undefined command",
7d29a247 DG	40	[ LTTCOMM_ERR_INDEX(LTTCOMM_NOT_IMPLEMENTED) ] = "Not implemented",
7d29a247 DG	41	[ LTTCOMM_ERR_INDEX(LTTCOMM_UNKNOWN_DOMAIN) ] = "Unknown tracing domain",
fac6795d DG	42	[ LTTCOMM_ERR_INDEX(LTTCOMM_NO_SESSION) ] = "No session found",
fac6795d DG	43	[ LTTCOMM_ERR_INDEX(LTTCOMM_LIST_FAIL) ] = "Unable to list traceable apps",
e065084a	44	[ LTTCOMM_ERR_INDEX(LTTCOMM_NO_APPS) ] = "No traceable apps found",
f3ed775e	45	[ LTTCOMM_ERR_INDEX(LTTCOMM_SESS_NOT_FOUND) ] = "Session name not found",
ce3d728c	46	[ LTTCOMM_ERR_INDEX(LTTCOMM_NO_TRACE) ] = "No trace found",
ca95a216	47	[ LTTCOMM_ERR_INDEX(LTTCOMM_FATAL) ] = "Fatal error of the session daemon",
df0da139	48	[ LTTCOMM_ERR_INDEX(LTTCOMM_CREATE_FAIL) ] = "Create trace failed",
379473d2	49	[ LTTCOMM_ERR_INDEX(LTTCOMM_START_FAIL) ] = "Start trace failed",
520ff687	50	[ LTTCOMM_ERR_INDEX(LTTCOMM_STOP_FAIL) ] = "Stop trace failed",
379473d2 DG	51	[ LTTCOMM_ERR_INDEX(LTTCOMM_NO_TRACEABLE) ] = "App is not traceable",
379473d2 DG	52	[ LTTCOMM_ERR_INDEX(LTTCOMM_SELECT_SESS) ] = "A session MUST be selected",
27673bb6	53	[ LTTCOMM_ERR_INDEX(LTTCOMM_EXIST_SESS) ] = "Session name already exist",
d9800920	54	[ LTTCOMM_ERR_INDEX(LTTCOMM_CONNECT_FAIL) ] = "Unable to connect to Unix socket",
2b0bf864	55	[ LTTCOMM_ERR_INDEX(LTTCOMM_APP_NOT_FOUND) ] = "Application not found",
8e0af1b4	56	[ LTTCOMM_ERR_INDEX(LTTCOMM_EPERM) ] = "Permission denied",
20fe2104	57	[ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_NA) ] = "Kernel tracer not available",
7d29a247	58	[ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_EVENT_EXIST) ] = "Kernel event already exists",
20fe2104 DG	59	[ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_SESS_FAIL) ] = "Kernel create session failed",
20fe2104 DG	60	[ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CHAN_FAIL) ] = "Kernel create channel failed",
f3ed775e	61	[ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CHAN_NOT_FOUND) ] = "Kernel channel not found",
26cc6b4e	62	[ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CHAN_DISABLE_FAIL) ] = "Disable kernel channel failed",
d36b8583	63	[ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CHAN_ENABLE_FAIL) ] = "Enable kernel channel failed",
d65106b1	64	[ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CONTEXT_FAIL) ] = "Add kernel context failed",
f34daff7 DG	65	[ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_ENABLE_FAIL) ] = "Enable kernel event failed",
f34daff7 DG	66	[ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_DISABLE_FAIL) ] = "Disable kernel event failed",
aaf26714	67	[ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_META_FAIL) ] = "Opening metadata failed",
8c0faa1d DG	68	[ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_START_FAIL) ] = "Starting kernel trace failed",
	69	[ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_STOP_FAIL) ] = "Stoping kernel trace failed",
	70	[ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CONSUMER_FAIL) ] = "Kernel consumer start failed",
	71	[ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_STREAM_FAIL) ] = "Kernel create stream failed",
	72	[ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_DIR_FAIL) ] = "Kernel trace directory creation failed",
	73	[ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_DIR_EXIST) ] = "Kernel trace directory already exist",
84291629	74	[ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_NO_SESSION) ] = "No kernel session found",
2ef84c95	75	[ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_LIST_FAIL) ] = "Listing kernel events failed",
0177d773	76	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_SESS_FAIL) ] = "UST create session failed",
2b0bf864	77	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CHAN_FAIL) ] = "UST create channel failed",
f6a9efaa	78	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CHAN_EXIST) ] = "UST channel already exist",
2bdd86d4 MD	79	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CHAN_NOT_FOUND) ] = "UST channel not found",
	80	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CHAN_DISABLE_FAIL) ] = "Disable UST channel failed",
	81	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CHAN_ENABLE_FAIL) ] = "Enable UST channel failed",
	82	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CONTEXT_FAIL) ] = "Add UST context failed",
	83	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_ENABLE_FAIL) ] = "Enable UST event failed",
	84	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_DISABLE_FAIL) ] = "Disable UST event failed",
	85	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_META_FAIL) ] = "Opening metadata failed",
	86	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_START_FAIL) ] = "Starting UST trace failed",
	87	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_STOP_FAIL) ] = "Stoping UST trace failed",
7753dea8 MD	88	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CONSUMER64_FAIL) ] = "64-bit UST consumer start failed",
7753dea8 MD	89	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CONSUMER32_FAIL) ] = "32-bit UST consumer start failed",
2bdd86d4 MD	90	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_STREAM_FAIL) ] = "UST create stream failed",
	91	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_DIR_FAIL) ] = "UST trace directory creation failed",
	92	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_DIR_EXIST) ] = "UST trace directory already exist",
	93	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_NO_SESSION) ] = "No UST session found",
	94	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_LIST_FAIL) ] = "Listing UST events failed",
3b25d04d	95	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_EVENT_EXIST) ] = "UST event already exist",
be4f0921	96	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_EVENT_NOT_FOUND)] = "UST event not found",
ae357384	97	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CONTEXT_EXIST)] = "UST context already exist",
3bd1e081 MD	98	[ LTTCOMM_ERR_INDEX(CONSUMERD_COMMAND_SOCK_READY) ] = "consumerd command socket ready",
	99	[ LTTCOMM_ERR_INDEX(CONSUMERD_SUCCESS_RECV_FD) ] = "consumerd success on receiving fds",
	100	[ LTTCOMM_ERR_INDEX(CONSUMERD_ERROR_RECV_FD) ] = "consumerd error on receiving fds",
f2fc6720	101	[ LTTCOMM_ERR_INDEX(CONSUMERD_ERROR_RECV_CMD) ] = "consumerd error on receiving command",
3bd1e081 MD	102	[ LTTCOMM_ERR_INDEX(CONSUMERD_POLL_ERROR) ] = "consumerd error in polling thread",
	103	[ LTTCOMM_ERR_INDEX(CONSUMERD_POLL_NVAL) ] = "consumerd polling on closed fd",
	104	[ LTTCOMM_ERR_INDEX(CONSUMERD_POLL_HUP) ] = "consumerd all fd hung up",
	105	[ LTTCOMM_ERR_INDEX(CONSUMERD_EXIT_SUCCESS) ] = "consumerd exiting normally",
	106	[ LTTCOMM_ERR_INDEX(CONSUMERD_EXIT_FAILURE) ] = "consumerd exiting on error",
	107	[ LTTCOMM_ERR_INDEX(CONSUMERD_OUTFD_ERROR) ] = "consumerd error opening the tracefile",
	108	[ LTTCOMM_ERR_INDEX(CONSUMERD_SPLICE_EBADF) ] = "consumerd splice EBADF",
	109	[ LTTCOMM_ERR_INDEX(CONSUMERD_SPLICE_EINVAL) ] = "consumerd splice EINVAL",
	110	[ LTTCOMM_ERR_INDEX(CONSUMERD_SPLICE_ENOMEM) ] = "consumerd splice ENOMEM",
	111	[ LTTCOMM_ERR_INDEX(CONSUMERD_SPLICE_ESPIPE) ] = "consumerd splice ESPIPE",
d65106b1	112	[ LTTCOMM_ERR_INDEX(LTTCOMM_NO_EVENT) ] = "Event not found",
fac6795d DG	113	};
	114
	115	/*
917216f6 DG	116	* Return ptr to string representing a human readable error code from the
917216f6 DG	117	* lttcomm_return_code enum.
fac6795d	118	*
917216f6	119	* These code MUST be negative in other to treat that as an error value.
fac6795d DG	120	*/
	121	const char *lttcomm_get_readable_code(enum lttcomm_return_code code)
	122	{
	123	int tmp_code = -code;
	124
	125	if (tmp_code >= LTTCOMM_OK && tmp_code < LTTCOMM_NR) {
	126	return lttcomm_readable_code[LTTCOMM_ERR_INDEX(tmp_code)];
	127	}
	128
	129	return "Unknown error code";
	130	}
	131
	132	/*
917216f6	133	* Connect to unix socket using the path name.
fac6795d DG	134	*/
	135	int lttcomm_connect_unix_sock(const char *pathname)
	136	{
686204ab MD	137	struct sockaddr_un sun;
686204ab MD	138	int fd;
a8afeb4a	139	int ret;
fac6795d	140
686204ab	141	fd = socket(PF_UNIX, SOCK_STREAM, 0);
fac6795d DG	142	if (fd < 0) {
fac6795d DG	143	perror("socket");
a8afeb4a	144	ret = fd;
fac6795d DG	145	goto error;
	146	}
	147
686204ab MD	148	memset(&sun, 0, sizeof(sun));
	149	sun.sun_family = AF_UNIX;
	150	strncpy(sun.sun_path, pathname, sizeof(sun.sun_path));
99497cd0	151	sun.sun_path[sizeof(sun.sun_path) - 1] = '\0';
fac6795d	152
686204ab MD	153	ret = connect(fd, (struct sockaddr *) &sun, sizeof(sun));
686204ab MD	154	if (ret < 0) {
a8afeb4a	155	/*
917216f6 DG	156	* Don't print message on connect error, because connect is used in
917216f6 DG	157	* normal execution to detect if sessiond is alive.
a8afeb4a MD	158	*/
a8afeb4a MD	159	goto error_connect;
686204ab	160	}
fac6795d	161
686204ab	162	return fd;
fac6795d	163
a8afeb4a MD	164	error_connect:
a8afeb4a MD	165	close(fd);
fac6795d	166	error:
a8afeb4a	167	return ret;
fac6795d DG	168	}
	169
	170	/*
917216f6 DG	171	* Do an accept(2) on the sock and return the new file descriptor. The socket
917216f6 DG	172	* MUST be bind(2) before.
fac6795d DG	173	*/
	174	int lttcomm_accept_unix_sock(int sock)
	175	{
	176	int new_fd;
	177	struct sockaddr_un sun;
	178	socklen_t len = 0;
	179
	180	/* Blocking call */
	181	new_fd = accept(sock, (struct sockaddr *) &sun, &len);
	182	if (new_fd < 0) {
	183	perror("accept");
fac6795d DG	184	}
	185
	186	return new_fd;
fac6795d DG	187	}
	188
	189	/*
917216f6 DG	190	* Creates a AF_UNIX local socket using pathname bind the socket upon creation
917216f6 DG	191	* and return the fd.
fac6795d DG	192	*/
	193	int lttcomm_create_unix_sock(const char *pathname)
	194	{
	195	struct sockaddr_un sun;
	196	int fd;
	197	int ret = -1;
	198
	199	/* Create server socket */
	200	if ((fd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0) {
	201	perror("socket");
	202	goto error;
	203	}
	204
	205	memset(&sun, 0, sizeof(sun));
	206	sun.sun_family = AF_UNIX;
99497cd0 MD	207	strncpy(sun.sun_path, pathname, sizeof(sun.sun_path));
99497cd0 MD	208	sun.sun_path[sizeof(sun.sun_path) - 1] = '\0';
fac6795d	209
7d8234d9 MD	210	/* Unlink the old file if present */
7d8234d9 MD	211	(void) unlink(pathname);
fac6795d DG	212	ret = bind(fd, (struct sockaddr *) &sun, sizeof(sun));
	213	if (ret < 0) {
	214	perror("bind");
	215	goto error;
	216	}
	217
	218	return fd;
	219
	220	error:
	221	return ret;
	222	}
	223
	224	/*
f158a754	225	* Make the socket listen using LTTNG_SESSIOND_COMM_MAX_LISTEN.
fac6795d DG	226	*/
	227	int lttcomm_listen_unix_sock(int sock)
	228	{
	229	int ret;
	230
f158a754	231	ret = listen(sock, LTTNG_SESSIOND_COMM_MAX_LISTEN);
fac6795d DG	232	if (ret < 0) {
	233	perror("listen");
	234	}
	235
	236	return ret;
	237	}
	238
	239	/*
917216f6 DG	240	* Receive data of size len in put that data into the buf param. Using recvmsg
917216f6 DG	241	* API.
fac6795d	242	*
917216f6	243	* Return the size of received data.
fac6795d DG	244	*/
	245	ssize_t lttcomm_recv_unix_sock(int sock, void *buf, size_t len)
	246	{
159c7ff4	247	struct msghdr msg = { 0 };
fac6795d DG	248	struct iovec iov[1];
	249	ssize_t ret = -1;
	250
fac6795d DG	251	iov[0].iov_base = buf;
	252	iov[0].iov_len = len;
	253	msg.msg_iov = iov;
	254	msg.msg_iovlen = 1;
	255
	256	ret = recvmsg(sock, &msg, 0);
	257	if (ret < 0) {
	258	perror("recvmsg");
	259	}
	260
	261	return ret;
	262	}
	263
	264	/*
917216f6	265	* Send buf data of size len. Using sendmsg API.
fac6795d	266	*
917216f6	267	* Return the size of sent data.
fac6795d DG	268	*/
	269	ssize_t lttcomm_send_unix_sock(int sock, void *buf, size_t len)
	270	{
159c7ff4	271	struct msghdr msg = { 0 };
fac6795d DG	272	struct iovec iov[1];
	273	ssize_t ret = -1;
	274
fac6795d DG	275	iov[0].iov_base = buf;
	276	iov[0].iov_len = len;
	277	msg.msg_iov = iov;
	278	msg.msg_iovlen = 1;
	279
	280	ret = sendmsg(sock, &msg, 0);
	281	if (ret < 0) {
	282	perror("sendmsg");
	283	}
	284
	285	return ret;
	286	}
87378cf5 DG	287
87378cf5 DG	288	/*
917216f6	289	* Shutdown cleanly a unix socket.
87378cf5 DG	290	*/
	291	int lttcomm_close_unix_sock(int sock)
	292	{
	293	int ret;
	294
	295	/* Shutdown receptions and transmissions */
	296	ret = shutdown(sock, SHUT_RDWR);
	297	if (ret < 0) {
	298	perror("shutdown");
	299	}
	300
	301	return ret;
	302	}
8c0faa1d DG	303
8c0faa1d DG	304	/*
3bd1e081 MD	305	* Send a message accompanied by fd(s) over a unix socket.
	306	*
	307	* Returns the size of data sent, or negative error value.
8c0faa1d	308	*/
3bd1e081	309	ssize_t lttcomm_send_fds_unix_sock(int sock, int *fds, size_t nb_fd)
8c0faa1d	310	{
159c7ff4	311	struct msghdr msg = { 0 };
8c0faa1d DG	312	struct cmsghdr *cmptr;
	313	struct iovec iov[1];
	314	ssize_t ret = -1;
	315	unsigned int sizeof_fds = nb_fd * sizeof(int);
	316	char tmp[CMSG_SPACE(sizeof_fds)];
3bd1e081	317	char dummy = 0;
8c0faa1d	318
3bd1e081 MD	319	if (nb_fd > LTTCOMM_MAX_SEND_FDS)
3bd1e081 MD	320	return -EINVAL;
8c0faa1d DG	321
	322	msg.msg_control = (caddr_t)tmp;
	323	msg.msg_controllen = CMSG_LEN(sizeof_fds);
	324
	325	cmptr = CMSG_FIRSTHDR(&msg);
8c0faa1d DG	326	cmptr->cmsg_level = SOL_SOCKET;
8c0faa1d DG	327	cmptr->cmsg_type = SCM_RIGHTS;
159c7ff4	328	cmptr->cmsg_len = CMSG_LEN(sizeof_fds);
8c0faa1d	329	memcpy(CMSG_DATA(cmptr), fds, sizeof_fds);
159c7ff4 MD	330	/* Sum of the length of all control messages in the buffer: */
159c7ff4 MD	331	msg.msg_controllen = cmptr->cmsg_len;
8c0faa1d	332
3bd1e081 MD	333	iov[0].iov_base = &dummy;
3bd1e081 MD	334	iov[0].iov_len = 1;
8c0faa1d DG	335	msg.msg_iov = iov;
	336	msg.msg_iovlen = 1;
	337
	338	ret = sendmsg(sock, &msg, 0);
	339	if (ret < 0) {
	340	perror("sendmsg");
	341	}
8c0faa1d DG	342	return ret;
8c0faa1d DG	343	}
09de5c68 DG	344
09de5c68 DG	345	/*
3bd1e081	346	* Recv a message accompanied by fd(s) from a unix socket.
09de5c68	347	*
3bd1e081 MD	348	* Returns the size of received data, or negative error value.
	349	*
	350	* Expect at most "nb_fd" file descriptors. Returns the number of fd
	351	* actually received in nb_fd.
09de5c68	352	*/
3bd1e081	353	ssize_t lttcomm_recv_fds_unix_sock(int sock, int *fds, size_t nb_fd)
09de5c68 DG	354	{
09de5c68 DG	355	struct iovec iov[1];
3bd1e081	356	ssize_t ret = 0;
09de5c68	357	struct cmsghdr *cmsg;
3bd1e081 MD	358	size_t sizeof_fds = nb_fd * sizeof(int);
3bd1e081 MD	359	char recv_fd[CMSG_SPACE(sizeof_fds)];
09de5c68	360	struct msghdr msg = { 0 };
3bd1e081	361	char dummy;
09de5c68 DG	362
09de5c68 DG	363	/* Prepare to receive the structures */
3bd1e081 MD	364	iov[0].iov_base = &dummy;
3bd1e081 MD	365	iov[0].iov_len = 1;
09de5c68 DG	366	msg.msg_iov = iov;
	367	msg.msg_iovlen = 1;
	368	msg.msg_control = recv_fd;
	369	msg.msg_controllen = sizeof(recv_fd);
	370
	371	ret = recvmsg(sock, &msg, 0);
	372	if (ret < 0) {
	373	perror("recvmsg fds");
	374	goto end;
	375	}
3bd1e081 MD	376	if (ret != 1) {
	377	fprintf(stderr, "Error: Received %zd bytes, expected %d\n",
	378	ret, 1);
	379	goto end;
	380	}
	381	if (msg.msg_flags & MSG_CTRUNC) {
	382	fprintf(stderr, "Error: Control message truncated.\n");
	383	ret = -1;
09de5c68 DG	384	goto end;
09de5c68 DG	385	}
09de5c68 DG	386	cmsg = CMSG_FIRSTHDR(&msg);
09de5c68 DG	387	if (!cmsg) {
3bd1e081	388	fprintf(stderr, "Error: Invalid control message header\n");
09de5c68 DG	389	ret = -1;
	390	goto end;
	391	}
09de5c68	392	if (cmsg->cmsg_level != SOL_SOCKET \|\| cmsg->cmsg_type != SCM_RIGHTS) {
3bd1e081	393	fprintf(stderr, "Didn't received any fd\n");
09de5c68 DG	394	ret = -1;
	395	goto end;
	396	}
3bd1e081 MD	397	if (cmsg->cmsg_len != CMSG_LEN(sizeof_fds)) {
	398	fprintf(stderr, "Error: Received %zu bytes of ancillary data, expected %zu\n",
	399	cmsg->cmsg_len, CMSG_LEN(sizeof_fds));
	400	ret = -1;
	401	goto end;
09de5c68	402	}
3bd1e081 MD	403	memcpy(fds, CMSG_DATA(cmsg), sizeof_fds);
3bd1e081 MD	404	ret = sizeof_fds;
09de5c68 DG	405	end:
	406	return ret;
	407	}
d19d9ada DG	408
	409	/*
	410	* Send a message with credentials over a unix socket.
	411	*
	412	* Returns the size of data sent, or negative error value.
	413	*/
	414	ssize_t lttcomm_send_creds_unix_sock(int sock, void *buf, size_t len)
	415	{
	416	struct msghdr msg = { 0 };
	417	struct cmsghdr *cmptr;
	418	struct iovec iov[1];
	419	ssize_t ret = -1;
	420	struct ucred *creds;
	421	size_t sizeof_cred = sizeof(struct ucred);
	422	char anc_buf[CMSG_SPACE(sizeof_cred)];
	423
	424	iov[0].iov_base = buf;
	425	iov[0].iov_len = len;
	426	msg.msg_iov = iov;
	427	msg.msg_iovlen = 1;
	428
	429	msg.msg_control = (caddr_t) anc_buf;
	430	msg.msg_controllen = CMSG_LEN(sizeof_cred);
	431
	432	cmptr = CMSG_FIRSTHDR(&msg);
	433	cmptr->cmsg_level = SOL_SOCKET;
	434	cmptr->cmsg_type = SCM_CREDENTIALS;
	435	cmptr->cmsg_len = CMSG_LEN(sizeof_cred);
	436
	437	creds = (struct ucred *) CMSG_DATA(cmptr);
	438
	439	creds->uid = geteuid();
	440	creds->gid = getegid();
	441	creds->pid = getpid();
	442
	443	ret = sendmsg(sock, &msg, 0);
	444	if (ret < 0) {
	445	perror("sendmsg");
	446	}
	447
	448	return ret;
	449	}
	450
	451	/*
	452	* Recv a message accompanied with credentials from a unix socket.
	453	*
	454	* Returns the size of received data, or negative error value.
	455	*/
	456	ssize_t lttcomm_recv_creds_unix_sock(int sock, void *buf, size_t len,
	457	struct ucred *creds)
	458	{
	459	struct msghdr msg = { 0 };
	460	struct cmsghdr *cmptr;
	461	struct iovec iov[1];
	462	ssize_t ret;
	463	size_t sizeof_cred = sizeof(struct ucred);
	464	char anc_buf[CMSG_SPACE(sizeof_cred)];
	465
	466	/* Not allowed */
	467	if (creds == NULL) {
	468	ret = -1;
	469	goto end;
	470	}
	471
472	/* Prepare to receive the structures */
473	iov[0].iov_base = buf;
474	iov[0].iov_len = len;
475	msg.msg_iov = iov;
476	msg.msg_iovlen = 1;
477
478	msg.msg_control = anc_buf;
479	msg.msg_controllen = sizeof(anc_buf);
480
481	ret = recvmsg(sock, &msg, 0);
482	if (ret < 0) {
483	perror("recvmsg fds");
484	goto end;
485	}
486
487	if (msg.msg_flags & MSG_CTRUNC) {
488	fprintf(stderr, "Error: Control message truncated.\n");
489	ret = -1;
490	goto end;
491	}
492
493	cmptr = CMSG_FIRSTHDR(&msg);
494	if (cmptr == NULL) {
495	fprintf(stderr, "Error: Invalid control message header\n");
496	ret = -1;
497	goto end;
498	}
499
500	if (cmptr->cmsg_level != SOL_SOCKET \|\|
501	cmptr->cmsg_type != SCM_CREDENTIALS) {
502	fprintf(stderr, "Didn't received any credentials\n");
503	ret = -1;
504	goto end;
505	}
506
507	if (cmptr->cmsg_len != CMSG_LEN(sizeof_cred)) {
508	fprintf(stderr, "Error: Received %zu bytes of ancillary data, expected %zu\n",
509	cmptr->cmsg_len, CMSG_LEN(sizeof_cred));
510	ret = -1;
511	goto end;
512	}
513
514	memcpy(creds, CMSG_DATA(cmptr), sizeof_cred);
515
516	end:
517	return ret;
518	}
519
520	/*
521	* Set socket option to use credentials passing.
522	*/
523	int lttcomm_setsockopt_creds_unix_sock(int sock)
524	{
525	int ret, on = 1;
526
527	/* Set socket for credentials retrieval */
528	ret = setsockopt(sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
529	if (ret < 0) {
530	perror("setsockopt creds unix sock");
531	}
532
533	return ret;
534	}