[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_DIR_FAIL) ] = "Create directory 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_CALIBRATE_FAIL) ] = "UST calibration 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(LTTCOMM_UST_CONTEXT_INVAL)] = "UST invalid context",
	[ 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, MSG_WAITALL);
	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",
ae856491	50	[ LTTCOMM_ERR_INDEX(LTTCOMM_CREATE_DIR_FAIL) ] = "Create directory 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",
4466912f	79	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CALIBRATE_FAIL) ] = "UST calibration failed",
e0c7ec2b	80	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_VERSION) ] = "UST tracer version is not compatible",
0177d773	81	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_SESS_FAIL) ] = "UST create session failed",
2b0bf864	82	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CHAN_FAIL) ] = "UST create channel failed",
f6a9efaa	83	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CHAN_EXIST) ] = "UST channel already exist",
2bdd86d4 MD	84	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CHAN_NOT_FOUND) ] = "UST channel not found",
	85	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CHAN_DISABLE_FAIL) ] = "Disable UST channel failed",
	86	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CHAN_ENABLE_FAIL) ] = "Enable UST channel failed",
	87	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CONTEXT_FAIL) ] = "Add UST context failed",
	88	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_ENABLE_FAIL) ] = "Enable UST event failed",
	89	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_DISABLE_FAIL) ] = "Disable UST event failed",
	90	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_META_FAIL) ] = "Opening metadata failed",
	91	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_START_FAIL) ] = "Starting UST trace failed",
	92	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_STOP_FAIL) ] = "Stoping UST trace failed",
7753dea8 MD	93	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CONSUMER64_FAIL) ] = "64-bit UST consumer start failed",
7753dea8 MD	94	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CONSUMER32_FAIL) ] = "32-bit UST consumer start failed",
2bdd86d4 MD	95	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_STREAM_FAIL) ] = "UST create stream failed",
	96	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_DIR_FAIL) ] = "UST trace directory creation failed",
	97	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_DIR_EXIST) ] = "UST trace directory already exist",
	98	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_NO_SESSION) ] = "No UST session found",
	99	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_LIST_FAIL) ] = "Listing UST events failed",
3b25d04d	100	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_EVENT_EXIST) ] = "UST event already exist",
be4f0921	101	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_EVENT_NOT_FOUND)] = "UST event not found",
ae357384	102	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CONTEXT_EXIST)] = "UST context already exist",
ae856491	103	[ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CONTEXT_INVAL)] = "UST invalid context",
3bd1e081 MD	104	[ LTTCOMM_ERR_INDEX(CONSUMERD_COMMAND_SOCK_READY) ] = "consumerd command socket ready",
	105	[ LTTCOMM_ERR_INDEX(CONSUMERD_SUCCESS_RECV_FD) ] = "consumerd success on receiving fds",
	106	[ LTTCOMM_ERR_INDEX(CONSUMERD_ERROR_RECV_FD) ] = "consumerd error on receiving fds",
f2fc6720	107	[ LTTCOMM_ERR_INDEX(CONSUMERD_ERROR_RECV_CMD) ] = "consumerd error on receiving command",
3bd1e081 MD	108	[ LTTCOMM_ERR_INDEX(CONSUMERD_POLL_ERROR) ] = "consumerd error in polling thread",
	109	[ LTTCOMM_ERR_INDEX(CONSUMERD_POLL_NVAL) ] = "consumerd polling on closed fd",
	110	[ LTTCOMM_ERR_INDEX(CONSUMERD_POLL_HUP) ] = "consumerd all fd hung up",
	111	[ LTTCOMM_ERR_INDEX(CONSUMERD_EXIT_SUCCESS) ] = "consumerd exiting normally",
	112	[ LTTCOMM_ERR_INDEX(CONSUMERD_EXIT_FAILURE) ] = "consumerd exiting on error",
	113	[ LTTCOMM_ERR_INDEX(CONSUMERD_OUTFD_ERROR) ] = "consumerd error opening the tracefile",
	114	[ LTTCOMM_ERR_INDEX(CONSUMERD_SPLICE_EBADF) ] = "consumerd splice EBADF",
	115	[ LTTCOMM_ERR_INDEX(CONSUMERD_SPLICE_EINVAL) ] = "consumerd splice EINVAL",
	116	[ LTTCOMM_ERR_INDEX(CONSUMERD_SPLICE_ENOMEM) ] = "consumerd splice ENOMEM",
	117	[ LTTCOMM_ERR_INDEX(CONSUMERD_SPLICE_ESPIPE) ] = "consumerd splice ESPIPE",
d65106b1	118	[ LTTCOMM_ERR_INDEX(LTTCOMM_NO_EVENT) ] = "Event not found",
fac6795d DG	119	};
	120
	121	/*
917216f6 DG	122	* Return ptr to string representing a human readable error code from the
917216f6 DG	123	* lttcomm_return_code enum.
fac6795d	124	*
917216f6	125	* These code MUST be negative in other to treat that as an error value.
fac6795d DG	126	*/
	127	const char *lttcomm_get_readable_code(enum lttcomm_return_code code)
	128	{
	129	int tmp_code = -code;
	130
	131	if (tmp_code >= LTTCOMM_OK && tmp_code < LTTCOMM_NR) {
	132	return lttcomm_readable_code[LTTCOMM_ERR_INDEX(tmp_code)];
	133	}
	134
	135	return "Unknown error code";
	136	}
	137
	138	/*
917216f6	139	* Connect to unix socket using the path name.
fac6795d DG	140	*/
	141	int lttcomm_connect_unix_sock(const char *pathname)
	142	{
686204ab MD	143	struct sockaddr_un sun;
686204ab MD	144	int fd;
a8afeb4a	145	int ret;
fac6795d	146
686204ab	147	fd = socket(PF_UNIX, SOCK_STREAM, 0);
fac6795d DG	148	if (fd < 0) {
fac6795d DG	149	perror("socket");
a8afeb4a	150	ret = fd;
fac6795d DG	151	goto error;
	152	}
	153
686204ab MD	154	memset(&sun, 0, sizeof(sun));
	155	sun.sun_family = AF_UNIX;
	156	strncpy(sun.sun_path, pathname, sizeof(sun.sun_path));
99497cd0	157	sun.sun_path[sizeof(sun.sun_path) - 1] = '\0';
fac6795d	158
686204ab MD	159	ret = connect(fd, (struct sockaddr *) &sun, sizeof(sun));
686204ab MD	160	if (ret < 0) {
a8afeb4a	161	/*
917216f6 DG	162	* Don't print message on connect error, because connect is used in
917216f6 DG	163	* normal execution to detect if sessiond is alive.
a8afeb4a MD	164	*/
a8afeb4a MD	165	goto error_connect;
686204ab	166	}
fac6795d	167
686204ab	168	return fd;
fac6795d	169
a8afeb4a MD	170	error_connect:
a8afeb4a MD	171	close(fd);
fac6795d	172	error:
a8afeb4a	173	return ret;
fac6795d DG	174	}
	175
	176	/*
917216f6 DG	177	* Do an accept(2) on the sock and return the new file descriptor. The socket
917216f6 DG	178	* MUST be bind(2) before.
fac6795d DG	179	*/
	180	int lttcomm_accept_unix_sock(int sock)
	181	{
	182	int new_fd;
	183	struct sockaddr_un sun;
	184	socklen_t len = 0;
	185
	186	/* Blocking call */
	187	new_fd = accept(sock, (struct sockaddr *) &sun, &len);
	188	if (new_fd < 0) {
	189	perror("accept");
fac6795d DG	190	}
	191
	192	return new_fd;
fac6795d DG	193	}
	194
	195	/*
917216f6 DG	196	* Creates a AF_UNIX local socket using pathname bind the socket upon creation
917216f6 DG	197	* and return the fd.
fac6795d DG	198	*/
	199	int lttcomm_create_unix_sock(const char *pathname)
	200	{
	201	struct sockaddr_un sun;
	202	int fd;
	203	int ret = -1;
	204
	205	/* Create server socket */
	206	if ((fd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0) {
	207	perror("socket");
	208	goto error;
	209	}
	210
	211	memset(&sun, 0, sizeof(sun));
	212	sun.sun_family = AF_UNIX;
99497cd0 MD	213	strncpy(sun.sun_path, pathname, sizeof(sun.sun_path));
99497cd0 MD	214	sun.sun_path[sizeof(sun.sun_path) - 1] = '\0';
fac6795d	215
7d8234d9 MD	216	/* Unlink the old file if present */
7d8234d9 MD	217	(void) unlink(pathname);
fac6795d DG	218	ret = bind(fd, (struct sockaddr *) &sun, sizeof(sun));
	219	if (ret < 0) {
	220	perror("bind");
	221	goto error;
	222	}
	223
	224	return fd;
	225
	226	error:
	227	return ret;
	228	}
	229
	230	/*
f158a754	231	* Make the socket listen using LTTNG_SESSIOND_COMM_MAX_LISTEN.
fac6795d DG	232	*/
	233	int lttcomm_listen_unix_sock(int sock)
	234	{
	235	int ret;
	236
f158a754	237	ret = listen(sock, LTTNG_SESSIOND_COMM_MAX_LISTEN);
fac6795d DG	238	if (ret < 0) {
	239	perror("listen");
	240	}
	241
	242	return ret;
	243	}
	244
	245	/*
917216f6 DG	246	* Receive data of size len in put that data into the buf param. Using recvmsg
917216f6 DG	247	* API.
fac6795d	248	*
917216f6	249	* Return the size of received data.
fac6795d DG	250	*/
	251	ssize_t lttcomm_recv_unix_sock(int sock, void *buf, size_t len)
	252	{
159c7ff4	253	struct msghdr msg = { 0 };
fac6795d DG	254	struct iovec iov[1];
	255	ssize_t ret = -1;
	256
fac6795d DG	257	iov[0].iov_base = buf;
	258	iov[0].iov_len = len;
	259	msg.msg_iov = iov;
	260	msg.msg_iovlen = 1;
	261
8266852e	262	ret = recvmsg(sock, &msg, MSG_WAITALL);
fac6795d DG	263	if (ret < 0) {
	264	perror("recvmsg");
	265	}
	266
	267	return ret;
	268	}
	269
	270	/*
917216f6	271	* Send buf data of size len. Using sendmsg API.
fac6795d	272	*
917216f6	273	* Return the size of sent data.
fac6795d DG	274	*/
	275	ssize_t lttcomm_send_unix_sock(int sock, void *buf, size_t len)
	276	{
159c7ff4	277	struct msghdr msg = { 0 };
fac6795d DG	278	struct iovec iov[1];
	279	ssize_t ret = -1;
	280
fac6795d DG	281	iov[0].iov_base = buf;
	282	iov[0].iov_len = len;
	283	msg.msg_iov = iov;
	284	msg.msg_iovlen = 1;
	285
	286	ret = sendmsg(sock, &msg, 0);
	287	if (ret < 0) {
	288	perror("sendmsg");
	289	}
	290
	291	return ret;
	292	}
87378cf5 DG	293
87378cf5 DG	294	/*
917216f6	295	* Shutdown cleanly a unix socket.
87378cf5 DG	296	*/
	297	int lttcomm_close_unix_sock(int sock)
	298	{
	299	int ret;
	300
	301	/* Shutdown receptions and transmissions */
	302	ret = shutdown(sock, SHUT_RDWR);
	303	if (ret < 0) {
	304	perror("shutdown");
	305	}
	306
	307	return ret;
	308	}
8c0faa1d DG	309
8c0faa1d DG	310	/*
3bd1e081 MD	311	* Send a message accompanied by fd(s) over a unix socket.
	312	*
	313	* Returns the size of data sent, or negative error value.
8c0faa1d	314	*/
3bd1e081	315	ssize_t lttcomm_send_fds_unix_sock(int sock, int *fds, size_t nb_fd)
8c0faa1d	316	{
159c7ff4	317	struct msghdr msg = { 0 };
8c0faa1d DG	318	struct cmsghdr *cmptr;
	319	struct iovec iov[1];
	320	ssize_t ret = -1;
	321	unsigned int sizeof_fds = nb_fd * sizeof(int);
	322	char tmp[CMSG_SPACE(sizeof_fds)];
3bd1e081	323	char dummy = 0;
8c0faa1d	324
3bd1e081 MD	325	if (nb_fd > LTTCOMM_MAX_SEND_FDS)
3bd1e081 MD	326	return -EINVAL;
8c0faa1d DG	327
	328	msg.msg_control = (caddr_t)tmp;
	329	msg.msg_controllen = CMSG_LEN(sizeof_fds);
	330
	331	cmptr = CMSG_FIRSTHDR(&msg);
8c0faa1d DG	332	cmptr->cmsg_level = SOL_SOCKET;
8c0faa1d DG	333	cmptr->cmsg_type = SCM_RIGHTS;
159c7ff4	334	cmptr->cmsg_len = CMSG_LEN(sizeof_fds);
8c0faa1d	335	memcpy(CMSG_DATA(cmptr), fds, sizeof_fds);
159c7ff4 MD	336	/* Sum of the length of all control messages in the buffer: */
159c7ff4 MD	337	msg.msg_controllen = cmptr->cmsg_len;
8c0faa1d	338
3bd1e081 MD	339	iov[0].iov_base = &dummy;
3bd1e081 MD	340	iov[0].iov_len = 1;
8c0faa1d DG	341	msg.msg_iov = iov;
	342	msg.msg_iovlen = 1;
	343
	344	ret = sendmsg(sock, &msg, 0);
	345	if (ret < 0) {
	346	perror("sendmsg");
	347	}
8c0faa1d DG	348	return ret;
8c0faa1d DG	349	}
09de5c68 DG	350
09de5c68 DG	351	/*
3bd1e081	352	* Recv a message accompanied by fd(s) from a unix socket.
09de5c68	353	*
3bd1e081 MD	354	* Returns the size of received data, or negative error value.
	355	*
	356	* Expect at most "nb_fd" file descriptors. Returns the number of fd
	357	* actually received in nb_fd.
09de5c68	358	*/
3bd1e081	359	ssize_t lttcomm_recv_fds_unix_sock(int sock, int *fds, size_t nb_fd)
09de5c68 DG	360	{
09de5c68 DG	361	struct iovec iov[1];
3bd1e081	362	ssize_t ret = 0;
09de5c68	363	struct cmsghdr *cmsg;
3bd1e081 MD	364	size_t sizeof_fds = nb_fd * sizeof(int);
3bd1e081 MD	365	char recv_fd[CMSG_SPACE(sizeof_fds)];
09de5c68	366	struct msghdr msg = { 0 };
3bd1e081	367	char dummy;
09de5c68 DG	368
09de5c68 DG	369	/* Prepare to receive the structures */
3bd1e081 MD	370	iov[0].iov_base = &dummy;
3bd1e081 MD	371	iov[0].iov_len = 1;
09de5c68 DG	372	msg.msg_iov = iov;
	373	msg.msg_iovlen = 1;
	374	msg.msg_control = recv_fd;
	375	msg.msg_controllen = sizeof(recv_fd);
	376
	377	ret = recvmsg(sock, &msg, 0);
	378	if (ret < 0) {
	379	perror("recvmsg fds");
	380	goto end;
	381	}
3bd1e081 MD	382	if (ret != 1) {
	383	fprintf(stderr, "Error: Received %zd bytes, expected %d\n",
	384	ret, 1);
	385	goto end;
	386	}
	387	if (msg.msg_flags & MSG_CTRUNC) {
	388	fprintf(stderr, "Error: Control message truncated.\n");
	389	ret = -1;
09de5c68 DG	390	goto end;
09de5c68 DG	391	}
09de5c68 DG	392	cmsg = CMSG_FIRSTHDR(&msg);
09de5c68 DG	393	if (!cmsg) {
3bd1e081	394	fprintf(stderr, "Error: Invalid control message header\n");
09de5c68 DG	395	ret = -1;
	396	goto end;
	397	}
09de5c68	398	if (cmsg->cmsg_level != SOL_SOCKET \|\| cmsg->cmsg_type != SCM_RIGHTS) {
3bd1e081	399	fprintf(stderr, "Didn't received any fd\n");
09de5c68 DG	400	ret = -1;
	401	goto end;
	402	}
3bd1e081 MD	403	if (cmsg->cmsg_len != CMSG_LEN(sizeof_fds)) {
	404	fprintf(stderr, "Error: Received %zu bytes of ancillary data, expected %zu\n",
	405	cmsg->cmsg_len, CMSG_LEN(sizeof_fds));
	406	ret = -1;
	407	goto end;
09de5c68	408	}
3bd1e081 MD	409	memcpy(fds, CMSG_DATA(cmsg), sizeof_fds);
3bd1e081 MD	410	ret = sizeof_fds;
09de5c68 DG	411	end:
	412	return ret;
	413	}
d19d9ada DG	414
	415	/*
	416	* Send a message with credentials over a unix socket.
	417	*
	418	* Returns the size of data sent, or negative error value.
	419	*/
	420	ssize_t lttcomm_send_creds_unix_sock(int sock, void *buf, size_t len)
	421	{
	422	struct msghdr msg = { 0 };
	423	struct cmsghdr *cmptr;
	424	struct iovec iov[1];
	425	ssize_t ret = -1;
	426	struct ucred *creds;
	427	size_t sizeof_cred = sizeof(struct ucred);
	428	char anc_buf[CMSG_SPACE(sizeof_cred)];
	429
	430	iov[0].iov_base = buf;
	431	iov[0].iov_len = len;
	432	msg.msg_iov = iov;
	433	msg.msg_iovlen = 1;
	434
	435	msg.msg_control = (caddr_t) anc_buf;
	436	msg.msg_controllen = CMSG_LEN(sizeof_cred);
	437
	438	cmptr = CMSG_FIRSTHDR(&msg);
	439	cmptr->cmsg_level = SOL_SOCKET;
	440	cmptr->cmsg_type = SCM_CREDENTIALS;
	441	cmptr->cmsg_len = CMSG_LEN(sizeof_cred);
	442
	443	creds = (struct ucred *) CMSG_DATA(cmptr);
	444
	445	creds->uid = geteuid();
	446	creds->gid = getegid();
	447	creds->pid = getpid();
	448
	449	ret = sendmsg(sock, &msg, 0);
	450	if (ret < 0) {
	451	perror("sendmsg");
	452	}
	453
	454	return ret;
	455	}
	456
	457	/*
	458	* Recv a message accompanied with credentials from a unix socket.
	459	*
	460	* Returns the size of received data, or negative error value.
	461	*/
	462	ssize_t lttcomm_recv_creds_unix_sock(int sock, void *buf, size_t len,
	463	struct ucred *creds)
	464	{
	465	struct msghdr msg = { 0 };
	466	struct cmsghdr *cmptr;
	467	struct iovec iov[1];
	468	ssize_t ret;
	469	size_t sizeof_cred = sizeof(struct ucred);
	470	char anc_buf[CMSG_SPACE(sizeof_cred)];
	471
	472	/* Not allowed */
	473	if (creds == NULL) {
	474	ret = -1;
	475	goto end;
	476	}
	477
478	/* Prepare to receive the structures */
479	iov[0].iov_base = buf;
480	iov[0].iov_len = len;
481	msg.msg_iov = iov;
482	msg.msg_iovlen = 1;
483
484	msg.msg_control = anc_buf;
485	msg.msg_controllen = sizeof(anc_buf);
486
487	ret = recvmsg(sock, &msg, 0);
488	if (ret < 0) {
489	perror("recvmsg fds");
490	goto end;
491	}
492
493	if (msg.msg_flags & MSG_CTRUNC) {
494	fprintf(stderr, "Error: Control message truncated.\n");
495	ret = -1;
496	goto end;
497	}
498
499	cmptr = CMSG_FIRSTHDR(&msg);
500	if (cmptr == NULL) {
501	fprintf(stderr, "Error: Invalid control message header\n");
502	ret = -1;
503	goto end;
504	}
505
506	if (cmptr->cmsg_level != SOL_SOCKET \|\|
507	cmptr->cmsg_type != SCM_CREDENTIALS) {
508	fprintf(stderr, "Didn't received any credentials\n");
509	ret = -1;
510	goto end;
511	}
512
513	if (cmptr->cmsg_len != CMSG_LEN(sizeof_cred)) {
514	fprintf(stderr, "Error: Received %zu bytes of ancillary data, expected %zu\n",
515	cmptr->cmsg_len, CMSG_LEN(sizeof_cred));
516	ret = -1;
517	goto end;
518	}
519
520	memcpy(creds, CMSG_DATA(cmptr), sizeof_cred);
521
522	end:
523	return ret;
524	}
525
526	/*
527	* Set socket option to use credentials passing.
528	*/
529	int lttcomm_setsockopt_creds_unix_sock(int sock)
530	{
531	int ret, on = 1;
532
533	/* Set socket for credentials retrieval */
534	ret = setsockopt(sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
535	if (ret < 0) {
536	perror("setsockopt creds unix sock");
537	}
538
539	return ret;
540	}