[lttng-tools.git] / src / common / sessiond-comm / 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 <common/defaults.h>

#include "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_VERSION) ] = "Kernel tracer version is not compatible",
	[ 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_VERSION) ] = "UST tracer version is not compatible",
	[ 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
990570ed DG	31	#include <common/defaults.h>
990570ed DG	32
10a8a223	33	#include "sessiond-comm.h"
fac6795d DG	34
	35	/*
	36	* Human readable error message.
	37	*/
	38	static const char *lttcomm_readable_code[] = {
	39	[ LTTCOMM_ERR_INDEX(LTTCOMM_OK) ] = "Success",
	40	[ LTTCOMM_ERR_INDEX(LTTCOMM_ERR) ] = "Unknown error",
	41	[ LTTCOMM_ERR_INDEX(LTTCOMM_UND) ] = "Undefined command",
7d29a247 DG	42	[ LTTCOMM_ERR_INDEX(LTTCOMM_NOT_IMPLEMENTED) ] = "Not implemented",
7d29a247 DG	43	[ LTTCOMM_ERR_INDEX(LTTCOMM_UNKNOWN_DOMAIN) ] = "Unknown tracing domain",
fac6795d DG	44	[ LTTCOMM_ERR_INDEX(LTTCOMM_NO_SESSION) ] = "No session found",
fac6795d DG	45	[ LTTCOMM_ERR_INDEX(LTTCOMM_LIST_FAIL) ] = "Unable to list traceable apps",
e065084a	46	[ LTTCOMM_ERR_INDEX(LTTCOMM_NO_APPS) ] = "No traceable apps found",
f3ed775e	47	[ LTTCOMM_ERR_INDEX(LTTCOMM_SESS_NOT_FOUND) ] = "Session name not found",
ce3d728c	48	[ LTTCOMM_ERR_INDEX(LTTCOMM_NO_TRACE) ] = "No trace found",
ca95a216	49	[ LTTCOMM_ERR_INDEX(LTTCOMM_FATAL) ] = "Fatal error of the session daemon",
df0da139	50	[ LTTCOMM_ERR_INDEX(LTTCOMM_CREATE_FAIL) ] = "Create trace failed",
379473d2	51	[ LTTCOMM_ERR_INDEX(LTTCOMM_START_FAIL) ] = "Start trace failed",
520ff687	52	[ LTTCOMM_ERR_INDEX(LTTCOMM_STOP_FAIL) ] = "Stop trace failed",
379473d2 DG	53	[ LTTCOMM_ERR_INDEX(LTTCOMM_NO_TRACEABLE) ] = "App is not traceable",
379473d2 DG	54	[ LTTCOMM_ERR_INDEX(LTTCOMM_SELECT_SESS) ] = "A session MUST be selected",
27673bb6	55	[ LTTCOMM_ERR_INDEX(LTTCOMM_EXIST_SESS) ] = "Session name already exist",
d9800920	56	[ LTTCOMM_ERR_INDEX(LTTCOMM_CONNECT_FAIL) ] = "Unable to connect to Unix socket",
2b0bf864	57	[ LTTCOMM_ERR_INDEX(LTTCOMM_APP_NOT_FOUND) ] = "Application not found",
8e0af1b4	58	[ LTTCOMM_ERR_INDEX(LTTCOMM_EPERM) ] = "Permission denied",
20fe2104	59	[ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_NA) ] = "Kernel tracer not available",
394016d1	60	[ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_VERSION) ] = "Kernel tracer version is not compatible",
7d29a247	61	[ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_EVENT_EXIST) ] = "Kernel event already exists",
20fe2104 DG	62	[ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_SESS_FAIL) ] = "Kernel create session failed",
20fe2104 DG	63	[ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CHAN_FAIL) ] = "Kernel create channel failed",
f3ed775e	64	[ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CHAN_NOT_FOUND) ] = "Kernel channel not found",
26cc6b4e	65	[ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CHAN_DISABLE_FAIL) ] = "Disable kernel channel failed",
d36b8583	66	[ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CHAN_ENABLE_FAIL) ] = "Enable kernel channel failed",
d65106b1	67	[ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CONTEXT_FAIL) ] = "Add kernel context failed",
f34daff7 DG	68	[ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_ENABLE_FAIL) ] = "Enable kernel event failed",
f34daff7 DG	69	[ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_DISABLE_FAIL) ] = "Disable kernel event failed",
aaf26714	70	[ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_META_FAIL) ] = "Opening metadata failed",
8c0faa1d DG	71	[ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_START_FAIL) ] = "Starting kernel trace failed",
	72	[ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_STOP_FAIL) ] = "Stoping kernel trace failed",
	73	[ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CONSUMER_FAIL) ] = "Kernel consumer start failed",
	74	[ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_STREAM_FAIL) ] = "Kernel create stream failed",
	75	[ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_DIR_FAIL) ] = "Kernel trace directory creation failed",
	76	[ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_DIR_EXIST) ] = "Kernel trace directory already exist",
84291629	77	[ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_NO_SESSION) ] = "No kernel session found",
2ef84c95	78	[ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_LIST_FAIL) ] = "Listing kernel events failed",
e0c7ec2b	79	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_VERSION) ] = "UST tracer version is not compatible",
0177d773	80	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_SESS_FAIL) ] = "UST create session failed",
2b0bf864	81	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CHAN_FAIL) ] = "UST create channel failed",
f6a9efaa	82	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CHAN_EXIST) ] = "UST channel already exist",
2bdd86d4 MD	83	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CHAN_NOT_FOUND) ] = "UST channel not found",
	84	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CHAN_DISABLE_FAIL) ] = "Disable UST channel failed",
	85	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CHAN_ENABLE_FAIL) ] = "Enable UST channel failed",
	86	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CONTEXT_FAIL) ] = "Add UST context failed",
	87	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_ENABLE_FAIL) ] = "Enable UST event failed",
	88	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_DISABLE_FAIL) ] = "Disable UST event failed",
	89	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_META_FAIL) ] = "Opening metadata failed",
	90	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_START_FAIL) ] = "Starting UST trace failed",
	91	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_STOP_FAIL) ] = "Stoping UST trace failed",
7753dea8 MD	92	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CONSUMER64_FAIL) ] = "64-bit UST consumer start failed",
7753dea8 MD	93	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CONSUMER32_FAIL) ] = "32-bit UST consumer start failed",
2bdd86d4 MD	94	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_STREAM_FAIL) ] = "UST create stream failed",
	95	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_DIR_FAIL) ] = "UST trace directory creation failed",
	96	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_DIR_EXIST) ] = "UST trace directory already exist",
	97	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_NO_SESSION) ] = "No UST session found",
	98	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_LIST_FAIL) ] = "Listing UST events failed",
3b25d04d	99	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_EVENT_EXIST) ] = "UST event already exist",
be4f0921	100	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_EVENT_NOT_FOUND)] = "UST event not found",
ae357384	101	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CONTEXT_EXIST)] = "UST context already exist",
3bd1e081 MD	102	[ LTTCOMM_ERR_INDEX(CONSUMERD_COMMAND_SOCK_READY) ] = "consumerd command socket ready",
	103	[ LTTCOMM_ERR_INDEX(CONSUMERD_SUCCESS_RECV_FD) ] = "consumerd success on receiving fds",
	104	[ LTTCOMM_ERR_INDEX(CONSUMERD_ERROR_RECV_FD) ] = "consumerd error on receiving fds",
f2fc6720	105	[ LTTCOMM_ERR_INDEX(CONSUMERD_ERROR_RECV_CMD) ] = "consumerd error on receiving command",
3bd1e081 MD	106	[ LTTCOMM_ERR_INDEX(CONSUMERD_POLL_ERROR) ] = "consumerd error in polling thread",
	107	[ LTTCOMM_ERR_INDEX(CONSUMERD_POLL_NVAL) ] = "consumerd polling on closed fd",
	108	[ LTTCOMM_ERR_INDEX(CONSUMERD_POLL_HUP) ] = "consumerd all fd hung up",
	109	[ LTTCOMM_ERR_INDEX(CONSUMERD_EXIT_SUCCESS) ] = "consumerd exiting normally",
	110	[ LTTCOMM_ERR_INDEX(CONSUMERD_EXIT_FAILURE) ] = "consumerd exiting on error",
	111	[ LTTCOMM_ERR_INDEX(CONSUMERD_OUTFD_ERROR) ] = "consumerd error opening the tracefile",
	112	[ LTTCOMM_ERR_INDEX(CONSUMERD_SPLICE_EBADF) ] = "consumerd splice EBADF",
	113	[ LTTCOMM_ERR_INDEX(CONSUMERD_SPLICE_EINVAL) ] = "consumerd splice EINVAL",
	114	[ LTTCOMM_ERR_INDEX(CONSUMERD_SPLICE_ENOMEM) ] = "consumerd splice ENOMEM",
	115	[ LTTCOMM_ERR_INDEX(CONSUMERD_SPLICE_ESPIPE) ] = "consumerd splice ESPIPE",
d65106b1	116	[ LTTCOMM_ERR_INDEX(LTTCOMM_NO_EVENT) ] = "Event not found",
fac6795d DG	117	};
	118
	119	/*
917216f6 DG	120	* Return ptr to string representing a human readable error code from the
917216f6 DG	121	* lttcomm_return_code enum.
fac6795d	122	*
917216f6	123	* These code MUST be negative in other to treat that as an error value.
fac6795d DG	124	*/
	125	const char *lttcomm_get_readable_code(enum lttcomm_return_code code)
	126	{
	127	int tmp_code = -code;
	128
	129	if (tmp_code >= LTTCOMM_OK && tmp_code < LTTCOMM_NR) {
	130	return lttcomm_readable_code[LTTCOMM_ERR_INDEX(tmp_code)];
	131	}
	132
	133	return "Unknown error code";
	134	}
	135
	136	/*
917216f6	137	* Connect to unix socket using the path name.
fac6795d DG	138	*/
	139	int lttcomm_connect_unix_sock(const char *pathname)
	140	{
686204ab MD	141	struct sockaddr_un sun;
686204ab MD	142	int fd;
a8afeb4a	143	int ret;
fac6795d	144
686204ab	145	fd = socket(PF_UNIX, SOCK_STREAM, 0);
fac6795d DG	146	if (fd < 0) {
fac6795d DG	147	perror("socket");
a8afeb4a	148	ret = fd;
fac6795d DG	149	goto error;
	150	}
	151
686204ab MD	152	memset(&sun, 0, sizeof(sun));
	153	sun.sun_family = AF_UNIX;
	154	strncpy(sun.sun_path, pathname, sizeof(sun.sun_path));
99497cd0	155	sun.sun_path[sizeof(sun.sun_path) - 1] = '\0';
fac6795d	156
686204ab MD	157	ret = connect(fd, (struct sockaddr *) &sun, sizeof(sun));
686204ab MD	158	if (ret < 0) {
a8afeb4a	159	/*
917216f6 DG	160	* Don't print message on connect error, because connect is used in
917216f6 DG	161	* normal execution to detect if sessiond is alive.
a8afeb4a MD	162	*/
a8afeb4a MD	163	goto error_connect;
686204ab	164	}
fac6795d	165
686204ab	166	return fd;
fac6795d	167
a8afeb4a MD	168	error_connect:
a8afeb4a MD	169	close(fd);
fac6795d	170	error:
a8afeb4a	171	return ret;
fac6795d DG	172	}
	173
	174	/*
917216f6 DG	175	* Do an accept(2) on the sock and return the new file descriptor. The socket
917216f6 DG	176	* MUST be bind(2) before.
fac6795d DG	177	*/
	178	int lttcomm_accept_unix_sock(int sock)
	179	{
	180	int new_fd;
	181	struct sockaddr_un sun;
	182	socklen_t len = 0;
	183
	184	/* Blocking call */
	185	new_fd = accept(sock, (struct sockaddr *) &sun, &len);
	186	if (new_fd < 0) {
	187	perror("accept");
fac6795d DG	188	}
	189
	190	return new_fd;
fac6795d DG	191	}
	192
	193	/*
917216f6 DG	194	* Creates a AF_UNIX local socket using pathname bind the socket upon creation
917216f6 DG	195	* and return the fd.
fac6795d DG	196	*/
	197	int lttcomm_create_unix_sock(const char *pathname)
	198	{
	199	struct sockaddr_un sun;
	200	int fd;
	201	int ret = -1;
	202
	203	/* Create server socket */
	204	if ((fd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0) {
	205	perror("socket");
	206	goto error;
	207	}
	208
	209	memset(&sun, 0, sizeof(sun));
	210	sun.sun_family = AF_UNIX;
99497cd0 MD	211	strncpy(sun.sun_path, pathname, sizeof(sun.sun_path));
99497cd0 MD	212	sun.sun_path[sizeof(sun.sun_path) - 1] = '\0';
fac6795d	213
7d8234d9 MD	214	/* Unlink the old file if present */
7d8234d9 MD	215	(void) unlink(pathname);
fac6795d DG	216	ret = bind(fd, (struct sockaddr *) &sun, sizeof(sun));
	217	if (ret < 0) {
	218	perror("bind");
	219	goto error;
	220	}
	221
	222	return fd;
	223
	224	error:
	225	return ret;
	226	}
	227
	228	/*
f158a754	229	* Make the socket listen using LTTNG_SESSIOND_COMM_MAX_LISTEN.
fac6795d DG	230	*/
	231	int lttcomm_listen_unix_sock(int sock)
	232	{
	233	int ret;
	234
f158a754	235	ret = listen(sock, LTTNG_SESSIOND_COMM_MAX_LISTEN);
fac6795d DG	236	if (ret < 0) {
	237	perror("listen");
	238	}
	239
	240	return ret;
	241	}
	242
	243	/*
917216f6 DG	244	* Receive data of size len in put that data into the buf param. Using recvmsg
917216f6 DG	245	* API.
fac6795d	246	*
917216f6	247	* Return the size of received data.
fac6795d DG	248	*/
	249	ssize_t lttcomm_recv_unix_sock(int sock, void *buf, size_t len)
	250	{
159c7ff4	251	struct msghdr msg = { 0 };
fac6795d DG	252	struct iovec iov[1];
	253	ssize_t ret = -1;
	254
fac6795d DG	255	iov[0].iov_base = buf;
	256	iov[0].iov_len = len;
	257	msg.msg_iov = iov;
	258	msg.msg_iovlen = 1;
	259
	260	ret = recvmsg(sock, &msg, 0);
	261	if (ret < 0) {
	262	perror("recvmsg");
	263	}
	264
	265	return ret;
	266	}
	267
	268	/*
917216f6	269	* Send buf data of size len. Using sendmsg API.
fac6795d	270	*
917216f6	271	* Return the size of sent data.
fac6795d DG	272	*/
	273	ssize_t lttcomm_send_unix_sock(int sock, void *buf, size_t len)
	274	{
159c7ff4	275	struct msghdr msg = { 0 };
fac6795d DG	276	struct iovec iov[1];
	277	ssize_t ret = -1;
	278
fac6795d DG	279	iov[0].iov_base = buf;
	280	iov[0].iov_len = len;
	281	msg.msg_iov = iov;
	282	msg.msg_iovlen = 1;
	283
	284	ret = sendmsg(sock, &msg, 0);
	285	if (ret < 0) {
	286	perror("sendmsg");
	287	}
	288
	289	return ret;
	290	}
87378cf5 DG	291
87378cf5 DG	292	/*
917216f6	293	* Shutdown cleanly a unix socket.
87378cf5 DG	294	*/
	295	int lttcomm_close_unix_sock(int sock)
	296	{
	297	int ret;
	298
	299	/* Shutdown receptions and transmissions */
	300	ret = shutdown(sock, SHUT_RDWR);
	301	if (ret < 0) {
	302	perror("shutdown");
	303	}
	304
	305	return ret;
	306	}
8c0faa1d DG	307
8c0faa1d DG	308	/*
3bd1e081 MD	309	* Send a message accompanied by fd(s) over a unix socket.
	310	*
	311	* Returns the size of data sent, or negative error value.
8c0faa1d	312	*/
3bd1e081	313	ssize_t lttcomm_send_fds_unix_sock(int sock, int *fds, size_t nb_fd)
8c0faa1d	314	{
159c7ff4	315	struct msghdr msg = { 0 };
8c0faa1d DG	316	struct cmsghdr *cmptr;
	317	struct iovec iov[1];
	318	ssize_t ret = -1;
	319	unsigned int sizeof_fds = nb_fd * sizeof(int);
	320	char tmp[CMSG_SPACE(sizeof_fds)];
3bd1e081	321	char dummy = 0;
8c0faa1d	322
3bd1e081 MD	323	if (nb_fd > LTTCOMM_MAX_SEND_FDS)
3bd1e081 MD	324	return -EINVAL;
8c0faa1d DG	325
	326	msg.msg_control = (caddr_t)tmp;
	327	msg.msg_controllen = CMSG_LEN(sizeof_fds);
	328
	329	cmptr = CMSG_FIRSTHDR(&msg);
8c0faa1d DG	330	cmptr->cmsg_level = SOL_SOCKET;
8c0faa1d DG	331	cmptr->cmsg_type = SCM_RIGHTS;
159c7ff4	332	cmptr->cmsg_len = CMSG_LEN(sizeof_fds);
8c0faa1d	333	memcpy(CMSG_DATA(cmptr), fds, sizeof_fds);
159c7ff4 MD	334	/* Sum of the length of all control messages in the buffer: */
159c7ff4 MD	335	msg.msg_controllen = cmptr->cmsg_len;
8c0faa1d	336
3bd1e081 MD	337	iov[0].iov_base = &dummy;
3bd1e081 MD	338	iov[0].iov_len = 1;
8c0faa1d DG	339	msg.msg_iov = iov;
	340	msg.msg_iovlen = 1;
	341
	342	ret = sendmsg(sock, &msg, 0);
	343	if (ret < 0) {
	344	perror("sendmsg");
	345	}
8c0faa1d DG	346	return ret;
8c0faa1d DG	347	}
09de5c68 DG	348
09de5c68 DG	349	/*
3bd1e081	350	* Recv a message accompanied by fd(s) from a unix socket.
09de5c68	351	*
3bd1e081 MD	352	* Returns the size of received data, or negative error value.
	353	*
	354	* Expect at most "nb_fd" file descriptors. Returns the number of fd
	355	* actually received in nb_fd.
09de5c68	356	*/
3bd1e081	357	ssize_t lttcomm_recv_fds_unix_sock(int sock, int *fds, size_t nb_fd)
09de5c68 DG	358	{
09de5c68 DG	359	struct iovec iov[1];
3bd1e081	360	ssize_t ret = 0;
09de5c68	361	struct cmsghdr *cmsg;
3bd1e081 MD	362	size_t sizeof_fds = nb_fd * sizeof(int);
3bd1e081 MD	363	char recv_fd[CMSG_SPACE(sizeof_fds)];
09de5c68	364	struct msghdr msg = { 0 };
3bd1e081	365	char dummy;
09de5c68 DG	366
09de5c68 DG	367	/* Prepare to receive the structures */
3bd1e081 MD	368	iov[0].iov_base = &dummy;
3bd1e081 MD	369	iov[0].iov_len = 1;
09de5c68 DG	370	msg.msg_iov = iov;
	371	msg.msg_iovlen = 1;
	372	msg.msg_control = recv_fd;
	373	msg.msg_controllen = sizeof(recv_fd);
	374
	375	ret = recvmsg(sock, &msg, 0);
	376	if (ret < 0) {
	377	perror("recvmsg fds");
	378	goto end;
	379	}
3bd1e081 MD	380	if (ret != 1) {
	381	fprintf(stderr, "Error: Received %zd bytes, expected %d\n",
	382	ret, 1);
	383	goto end;
	384	}
	385	if (msg.msg_flags & MSG_CTRUNC) {
	386	fprintf(stderr, "Error: Control message truncated.\n");
	387	ret = -1;
09de5c68 DG	388	goto end;
09de5c68 DG	389	}
09de5c68 DG	390	cmsg = CMSG_FIRSTHDR(&msg);
09de5c68 DG	391	if (!cmsg) {
3bd1e081	392	fprintf(stderr, "Error: Invalid control message header\n");
09de5c68 DG	393	ret = -1;
	394	goto end;
	395	}
09de5c68	396	if (cmsg->cmsg_level != SOL_SOCKET \|\| cmsg->cmsg_type != SCM_RIGHTS) {
3bd1e081	397	fprintf(stderr, "Didn't received any fd\n");
09de5c68 DG	398	ret = -1;
	399	goto end;
	400	}
3bd1e081 MD	401	if (cmsg->cmsg_len != CMSG_LEN(sizeof_fds)) {
	402	fprintf(stderr, "Error: Received %zu bytes of ancillary data, expected %zu\n",
	403	cmsg->cmsg_len, CMSG_LEN(sizeof_fds));
	404	ret = -1;
	405	goto end;
09de5c68	406	}
3bd1e081 MD	407	memcpy(fds, CMSG_DATA(cmsg), sizeof_fds);
3bd1e081 MD	408	ret = sizeof_fds;
09de5c68 DG	409	end:
	410	return ret;
	411	}
d19d9ada DG	412
	413	/*
	414	* Send a message with credentials over a unix socket.
	415	*
	416	* Returns the size of data sent, or negative error value.
	417	*/
	418	ssize_t lttcomm_send_creds_unix_sock(int sock, void *buf, size_t len)
	419	{
	420	struct msghdr msg = { 0 };
	421	struct cmsghdr *cmptr;
	422	struct iovec iov[1];
	423	ssize_t ret = -1;
	424	struct ucred *creds;
	425	size_t sizeof_cred = sizeof(struct ucred);
	426	char anc_buf[CMSG_SPACE(sizeof_cred)];
	427
	428	iov[0].iov_base = buf;
	429	iov[0].iov_len = len;
	430	msg.msg_iov = iov;
	431	msg.msg_iovlen = 1;
	432
	433	msg.msg_control = (caddr_t) anc_buf;
	434	msg.msg_controllen = CMSG_LEN(sizeof_cred);
	435
	436	cmptr = CMSG_FIRSTHDR(&msg);
	437	cmptr->cmsg_level = SOL_SOCKET;
	438	cmptr->cmsg_type = SCM_CREDENTIALS;
	439	cmptr->cmsg_len = CMSG_LEN(sizeof_cred);
	440
	441	creds = (struct ucred *) CMSG_DATA(cmptr);
	442
	443	creds->uid = geteuid();
	444	creds->gid = getegid();
	445	creds->pid = getpid();
	446
	447	ret = sendmsg(sock, &msg, 0);
	448	if (ret < 0) {
	449	perror("sendmsg");
	450	}
	451
	452	return ret;
	453	}
	454
	455	/*
	456	* Recv a message accompanied with credentials from a unix socket.
	457	*
	458	* Returns the size of received data, or negative error value.
	459	*/
	460	ssize_t lttcomm_recv_creds_unix_sock(int sock, void *buf, size_t len,
	461	struct ucred *creds)
	462	{
	463	struct msghdr msg = { 0 };
	464	struct cmsghdr *cmptr;
	465	struct iovec iov[1];
	466	ssize_t ret;
	467	size_t sizeof_cred = sizeof(struct ucred);
	468	char anc_buf[CMSG_SPACE(sizeof_cred)];
	469
	470	/* Not allowed */
	471	if (creds == NULL) {
	472	ret = -1;
	473	goto end;
	474	}
	475
476	/* Prepare to receive the structures */
477	iov[0].iov_base = buf;
478	iov[0].iov_len = len;
479	msg.msg_iov = iov;
480	msg.msg_iovlen = 1;
481
482	msg.msg_control = anc_buf;
483	msg.msg_controllen = sizeof(anc_buf);
484
485	ret = recvmsg(sock, &msg, 0);
486	if (ret < 0) {
487	perror("recvmsg fds");
488	goto end;
489	}
490
491	if (msg.msg_flags & MSG_CTRUNC) {
492	fprintf(stderr, "Error: Control message truncated.\n");
493	ret = -1;
494	goto end;
495	}
496
497	cmptr = CMSG_FIRSTHDR(&msg);
498	if (cmptr == NULL) {
499	fprintf(stderr, "Error: Invalid control message header\n");
500	ret = -1;
501	goto end;
502	}
503
504	if (cmptr->cmsg_level != SOL_SOCKET \|\|
505	cmptr->cmsg_type != SCM_CREDENTIALS) {
506	fprintf(stderr, "Didn't received any credentials\n");
507	ret = -1;
508	goto end;
509	}
510
511	if (cmptr->cmsg_len != CMSG_LEN(sizeof_cred)) {
512	fprintf(stderr, "Error: Received %zu bytes of ancillary data, expected %zu\n",
513	cmptr->cmsg_len, CMSG_LEN(sizeof_cred));
514	ret = -1;
515	goto end;
516	}
517
518	memcpy(creds, CMSG_DATA(cmptr), sizeof_cred);
519
520	end:
521	return ret;
522	}
523
524	/*
525	* Set socket option to use credentials passing.
526	*/
527	int lttcomm_setsockopt_creds_unix_sock(int sock)
528	{
529	int ret, on = 1;
530
531	/* Set socket for credentials retrieval */
532	ret = setsockopt(sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
533	if (ret < 0) {
534	perror("setsockopt creds unix sock");
535	}
536
537	return ret;
538	}