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