[lttng-tools.git] / src / common / sessiond-comm / unix.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, version 2 only,
 * as published by the Free Software Foundation.
 *
 * 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.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#define _GNU_SOURCE
#define _LGPL_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 <unistd.h>
#include <errno.h>

#include <common/common.h>

#include "unix.h"

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

	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:
	closeret = close(fd);
	if (closeret) {
		PERROR("close");
	}
error:
	return ret;
}

/*
 * Do an accept(2) on the sock and return the new file descriptor. The socket
 * MUST be bind(2) before.
 */
LTTNG_HIDDEN
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;
}

LTTNG_HIDDEN
int lttcomm_create_anon_unix_socketpair(int *fds)
{
	if (socketpair(PF_UNIX, SOCK_STREAM, 0, fds) < 0) {
		PERROR("socketpair");
		return -1;
	}
	return 0;
}

/*
 * Creates a AF_UNIX local socket using pathname bind the socket upon creation
 * and return the fd.
 */
LTTNG_HIDDEN
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:
	if (fd >= 0) {
		if (close(fd) < 0) {
			PERROR("close create unix sock");
		}
	}
	return ret;
}

/*
 * Make the socket listen using LTTNG_SESSIOND_COMM_MAX_LISTEN.
 */
LTTNG_HIDDEN
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.
 */
LTTNG_HIDDEN
ssize_t lttcomm_recv_unix_sock(int sock, void *buf, size_t len)
{
	struct msghdr msg;
	struct iovec iov[1];
	ssize_t ret = -1;
	size_t len_last;

	memset(&msg, 0, sizeof(msg));

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

	do {
		len_last = iov[0].iov_len;
		ret = recvmsg(sock, &msg, MSG_NOSIGNAL);
		if (ret > 0) {
			iov[0].iov_base += ret;
			iov[0].iov_len -= ret;
			assert(ret <= len_last);
		}
	} while ((ret > 0 && ret < len_last) || (ret < 0 && errno == EINTR));
	if (ret < 0) {
		PERROR("recvmsg");
	} else if (ret > 0) {
		ret = len;
	}
	/* Else ret = 0 meaning an orderly shutdown. */

	return ret;
}

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

	memset(&msg, 0, sizeof(msg));

	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) {
		/*
		 * Only warn about EPIPE when quiet mode is deactivated.
		 * We consider EPIPE as expected.
		 */
		if (errno != EPIPE || !lttng_opt_quiet) {
			PERROR("sendmsg");
		}
	}

	return ret;
}

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

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

	closeret = close(sock);
	if (closeret) {
		PERROR("close");
	}

	return ret;
}

/*
 * Send a message accompanied by fd(s) over a unix socket.
 *
 * Returns the size of data sent, or negative error value.
 */
LTTNG_HIDDEN
ssize_t lttcomm_send_fds_unix_sock(int sock, int *fds, size_t nb_fd)
{
	struct msghdr msg;
	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;

	memset(&msg, 0, sizeof(msg));
	memset(tmp, 0, CMSG_SPACE(sizeof_fds) * sizeof(char));

	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;

	do {
		ret = sendmsg(sock, &msg, 0);
	} while (ret < 0 && errno == EINTR);
	if (ret < 0) {
		/*
		 * Only warn about EPIPE when quiet mode is deactivated.
		 * We consider EPIPE as expected.
		 */
		if (errno != EPIPE || !lttng_opt_quiet) {
			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.
 */
LTTNG_HIDDEN
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;
	char dummy;

	memset(&msg, 0, sizeof(msg));

	/* 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);

	do {
		ret = recvmsg(sock, &msg, 0);
	} while (ret < 0 && errno == EINTR);
	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",
				(size_t) cmsg->cmsg_len, (size_t) 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.
 */
LTTNG_HIDDEN
ssize_t lttcomm_send_creds_unix_sock(int sock, void *buf, size_t len)
{
	struct msghdr msg;
	struct iovec iov[1];
	ssize_t ret = -1;
#ifdef __linux__
	struct cmsghdr *cmptr;
	size_t sizeof_cred = sizeof(lttng_sock_cred);
	char anc_buf[CMSG_SPACE(sizeof_cred)];
	lttng_sock_cred *creds;
#endif /* __linux__ */

	memset(&msg, 0, sizeof(msg));
	memset(anc_buf, 0, CMSG_SPACE(sizeof_cred) * sizeof(char));

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

#ifdef __linux__
	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 = LTTNG_SOCK_CREDS;
	cmptr->cmsg_len = CMSG_LEN(sizeof_cred);

	creds = (lttng_sock_cred*) CMSG_DATA(cmptr);

	LTTNG_SOCK_SET_UID_CRED(creds, geteuid());
	LTTNG_SOCK_SET_GID_CRED(creds, getegid());
	LTTNG_SOCK_SET_PID_CRED(creds, getpid());
#endif /* __linux__ */

	do {
		ret = sendmsg(sock, &msg, 0);
	} while (ret < 0 && errno == EINTR);
	if (ret < 0) {
		/*
		 * Only warn about EPIPE when quiet mode is deactivated.
		 * We consider EPIPE as expected.
		 */
		if (errno != EPIPE || !lttng_opt_quiet) {
			PERROR("sendmsg");
		}
	}
	return ret;
}

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

	memset(&msg, 0, sizeof(msg));

	/* 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;

#ifdef __linux__
	msg.msg_control = anc_buf;
	msg.msg_controllen = sizeof(anc_buf);
#endif /* __linux__ */

	do {
		len_last = iov[0].iov_len;
		ret = recvmsg(sock, &msg, 0);
		if (ret > 0) {
			iov[0].iov_base += ret;
			iov[0].iov_len -= ret;
			assert(ret <= len_last);
		}
	} while ((ret > 0 && ret < len_last) || (ret < 0 && errno == EINTR));
	if (ret < 0) {
		PERROR("recvmsg fds");
		goto end;
	} else if (ret > 0) {
		ret = len;
	}
	/* Else ret = 0 meaning an orderly shutdown. */

#ifdef __linux__
	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 != LTTNG_SOCK_CREDS) {
		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",
				(size_t) cmptr->cmsg_len, (size_t) CMSG_LEN(sizeof_cred));
		ret = -1;
		goto end;
	}

	memcpy(creds, CMSG_DATA(cmptr), sizeof_cred);
#elif (defined(__FreeBSD__) || defined(__CYGWIN__))
	{
		int peer_ret;

		peer_ret = getpeereid(sock, &creds->uid, &creds->gid);
		if (peer_ret != 0) {
			return peer_ret;
		}
	}
#else
#error "Please implement credential support for your OS."
#endif	/* __linux__ */

end:
	return ret;
}

/*
 * Set socket option to use credentials passing.
 */
#ifdef __linux__
LTTNG_HIDDEN
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;
}
#elif (defined(__FreeBSD__) || defined(__CYGWIN__))
LTTNG_HIDDEN
int lttcomm_setsockopt_creds_unix_sock(int sock)
{
	return 0;
}
#else
#error "Please implement credential support for your OS."
#endif /* __linux__ */
Commit	Line	Data
0d37f2bc DG	1	/*
	2	* Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
	3	* Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
	4	*
	5	* This program is free software; you can redistribute it and/or modify
	6	* it under the terms of the GNU General Public License, version 2 only,
	7	* as published by the Free Software Foundation.
	8	*
	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.
	13	*
	14	* You should have received a copy of the GNU General Public License along
	15	* with this program; if not, write to the Free Software Foundation, Inc.,
	16	* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
	17	*/
	18
	19	#define _GNU_SOURCE
6c1c0768	20	#define _LGPL_SOURCE
0d37f2bc DG	21	#include <assert.h>
	22	#include <limits.h>
	23	#include <stdio.h>
	24	#include <stdlib.h>
	25	#include <string.h>
	26	#include <sys/stat.h>
	27	#include <sys/types.h>
	28	#include <unistd.h>
	29	#include <errno.h>
	30
90e535ef	31	#include <common/common.h>
0d37f2bc DG	32
	33	#include "unix.h"
	34
	35	/*
	36	* Connect to unix socket using the path name.
	37	*/
90e535ef	38	LTTNG_HIDDEN
0d37f2bc DG	39	int lttcomm_connect_unix_sock(const char *pathname)
	40	{
	41	struct sockaddr_un sun;
	42	int fd, ret, closeret;
	43
	44	fd = socket(PF_UNIX, SOCK_STREAM, 0);
	45	if (fd < 0) {
	46	PERROR("socket");
	47	ret = fd;
	48	goto error;
	49	}
	50
	51	memset(&sun, 0, sizeof(sun));
	52	sun.sun_family = AF_UNIX;
	53	strncpy(sun.sun_path, pathname, sizeof(sun.sun_path));
	54	sun.sun_path[sizeof(sun.sun_path) - 1] = '\0';
	55
	56	ret = connect(fd, (struct sockaddr *) &sun, sizeof(sun));
	57	if (ret < 0) {
	58	/*
	59	* Don't print message on connect error, because connect is used in
	60	* normal execution to detect if sessiond is alive.
	61	*/
	62	goto error_connect;
	63	}
	64
	65	return fd;
	66
	67	error_connect:
	68	closeret = close(fd);
	69	if (closeret) {
	70	PERROR("close");
	71	}
	72	error:
	73	return ret;
	74	}
	75
	76	/*
	77	* Do an accept(2) on the sock and return the new file descriptor. The socket
	78	* MUST be bind(2) before.
	79	*/
90e535ef	80	LTTNG_HIDDEN
0d37f2bc DG	81	int lttcomm_accept_unix_sock(int sock)
	82	{
	83	int new_fd;
	84	struct sockaddr_un sun;
	85	socklen_t len = 0;
	86
	87	/* Blocking call */
	88	new_fd = accept(sock, (struct sockaddr *) &sun, &len);
	89	if (new_fd < 0) {
	90	PERROR("accept");
	91	}
	92
	93	return new_fd;
	94	}
	95
7567352f MD	96	LTTNG_HIDDEN
	97	int lttcomm_create_anon_unix_socketpair(int *fds)
	98	{
	99	if (socketpair(PF_UNIX, SOCK_STREAM, 0, fds) < 0) {
	100	PERROR("socketpair");
	101	return -1;
	102	}
	103	return 0;
	104	}
	105
0d37f2bc DG	106	/*
	107	* Creates a AF_UNIX local socket using pathname bind the socket upon creation
	108	* and return the fd.
	109	*/
90e535ef	110	LTTNG_HIDDEN
0d37f2bc DG	111	int lttcomm_create_unix_sock(const char *pathname)
	112	{
	113	struct sockaddr_un sun;
	114	int fd;
	115	int ret = -1;
	116
	117	/* Create server socket */
	118	if ((fd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0) {
	119	PERROR("socket");
	120	goto error;
	121	}
	122
	123	memset(&sun, 0, sizeof(sun));
	124	sun.sun_family = AF_UNIX;
	125	strncpy(sun.sun_path, pathname, sizeof(sun.sun_path));
	126	sun.sun_path[sizeof(sun.sun_path) - 1] = '\0';
	127
	128	/* Unlink the old file if present */
	129	(void) unlink(pathname);
	130	ret = bind(fd, (struct sockaddr *) &sun, sizeof(sun));
	131	if (ret < 0) {
	132	PERROR("bind");
	133	goto error;
	134	}
	135
	136	return fd;
	137
	138	error:
17e75273 DG	139	if (fd >= 0) {
	140	if (close(fd) < 0) {
	141	PERROR("close create unix sock");
	142	}
	143	}
0d37f2bc DG	144	return ret;
	145	}
	146
	147	/*
	148	* Make the socket listen using LTTNG_SESSIOND_COMM_MAX_LISTEN.
	149	*/
90e535ef	150	LTTNG_HIDDEN
0d37f2bc DG	151	int lttcomm_listen_unix_sock(int sock)
	152	{
	153	int ret;
	154
	155	ret = listen(sock, LTTNG_SESSIOND_COMM_MAX_LISTEN);
	156	if (ret < 0) {
	157	PERROR("listen");
	158	}
	159
	160	return ret;
	161	}
	162
	163	/*
	164	* Receive data of size len in put that data into the buf param. Using recvmsg
	165	* API.
	166	*
	167	* Return the size of received data.
	168	*/
90e535ef	169	LTTNG_HIDDEN
0d37f2bc DG	170	ssize_t lttcomm_recv_unix_sock(int sock, void *buf, size_t len)
	171	{
	172	struct msghdr msg;
	173	struct iovec iov[1];
	174	ssize_t ret = -1;
7c5aef62	175	size_t len_last;
0d37f2bc DG	176
	177	memset(&msg, 0, sizeof(msg));
	178
	179	iov[0].iov_base = buf;
	180	iov[0].iov_len = len;
	181	msg.msg_iov = iov;
	182	msg.msg_iovlen = 1;
	183
	184	do {
7c5aef62	185	len_last = iov[0].iov_len;
fbe49b3b	186	ret = recvmsg(sock, &msg, MSG_NOSIGNAL);
7c5aef62 DG	187	if (ret > 0) {
	188	iov[0].iov_base += ret;
	189	iov[0].iov_len -= ret;
	190	assert(ret <= len_last);
	191	}
	192	} while ((ret > 0 && ret < len_last) \|\| (ret < 0 && errno == EINTR));
0d37f2bc DG	193	if (ret < 0) {
0d37f2bc DG	194	PERROR("recvmsg");
7c5aef62 DG	195	} else if (ret > 0) {
7c5aef62 DG	196	ret = len;
0d37f2bc	197	}
7c5aef62	198	/* Else ret = 0 meaning an orderly shutdown. */
0d37f2bc DG	199
	200	return ret;
	201	}
	202
	203	/*
	204	* Send buf data of size len. Using sendmsg API.
	205	*
	206	* Return the size of sent data.
	207	*/
90e535ef	208	LTTNG_HIDDEN
0d37f2bc DG	209	ssize_t lttcomm_send_unix_sock(int sock, void *buf, size_t len)
	210	{
	211	struct msghdr msg;
	212	struct iovec iov[1];
	213	ssize_t ret = -1;
	214
	215	memset(&msg, 0, sizeof(msg));
	216
	217	iov[0].iov_base = buf;
	218	iov[0].iov_len = len;
	219	msg.msg_iov = iov;
	220	msg.msg_iovlen = 1;
	221
	222	ret = sendmsg(sock, &msg, 0);
	223	if (ret < 0) {
	224	/*
	225	* Only warn about EPIPE when quiet mode is deactivated.
	226	* We consider EPIPE as expected.
	227	*/
	228	if (errno != EPIPE \|\| !lttng_opt_quiet) {
	229	PERROR("sendmsg");
	230	}
	231	}
	232
	233	return ret;
	234	}
	235
	236	/*
	237	* Shutdown cleanly a unix socket.
	238	*/
90e535ef	239	LTTNG_HIDDEN
0d37f2bc DG	240	int lttcomm_close_unix_sock(int sock)
	241	{
	242	int ret, closeret;
	243
	244	/* Shutdown receptions and transmissions */
	245	ret = shutdown(sock, SHUT_RDWR);
	246	if (ret < 0) {
	247	PERROR("shutdown");
	248	}
	249
	250	closeret = close(sock);
	251	if (closeret) {
	252	PERROR("close");
	253	}
	254
	255	return ret;
	256	}
	257
	258	/*
	259	* Send a message accompanied by fd(s) over a unix socket.
	260	*
	261	* Returns the size of data sent, or negative error value.
	262	*/
90e535ef	263	LTTNG_HIDDEN
0d37f2bc DG	264	ssize_t lttcomm_send_fds_unix_sock(int sock, int *fds, size_t nb_fd)
	265	{
	266	struct msghdr msg;
	267	struct cmsghdr *cmptr;
	268	struct iovec iov[1];
	269	ssize_t ret = -1;
	270	unsigned int sizeof_fds = nb_fd * sizeof(int);
	271	char tmp[CMSG_SPACE(sizeof_fds)];
	272	char dummy = 0;
	273
	274	memset(&msg, 0, sizeof(msg));
c617c0c6	275	memset(tmp, 0, CMSG_SPACE(sizeof_fds) * sizeof(char));
0d37f2bc DG	276
	277	if (nb_fd > LTTCOMM_MAX_SEND_FDS)
	278	return -EINVAL;
	279
	280	msg.msg_control = (caddr_t)tmp;
	281	msg.msg_controllen = CMSG_LEN(sizeof_fds);
	282
	283	cmptr = CMSG_FIRSTHDR(&msg);
	284	cmptr->cmsg_level = SOL_SOCKET;
	285	cmptr->cmsg_type = SCM_RIGHTS;
	286	cmptr->cmsg_len = CMSG_LEN(sizeof_fds);
	287	memcpy(CMSG_DATA(cmptr), fds, sizeof_fds);
	288	/* Sum of the length of all control messages in the buffer: */
	289	msg.msg_controllen = cmptr->cmsg_len;
	290
	291	iov[0].iov_base = &dummy;
	292	iov[0].iov_len = 1;
	293	msg.msg_iov = iov;
	294	msg.msg_iovlen = 1;
	295
	296	do {
	297	ret = sendmsg(sock, &msg, 0);
	298	} while (ret < 0 && errno == EINTR);
	299	if (ret < 0) {
	300	/*
	301	* Only warn about EPIPE when quiet mode is deactivated.
	302	* We consider EPIPE as expected.
	303	*/
	304	if (errno != EPIPE \|\| !lttng_opt_quiet) {
	305	PERROR("sendmsg");
	306	}
	307	}
	308	return ret;
	309	}
	310
	311	/*
	312	* Recv a message accompanied by fd(s) from a unix socket.
	313	*
	314	* Returns the size of received data, or negative error value.
	315	*
	316	* Expect at most "nb_fd" file descriptors. Returns the number of fd
	317	* actually received in nb_fd.
	318	*/
90e535ef	319	LTTNG_HIDDEN
0d37f2bc DG	320	ssize_t lttcomm_recv_fds_unix_sock(int sock, int *fds, size_t nb_fd)
	321	{
	322	struct iovec iov[1];
	323	ssize_t ret = 0;
	324	struct cmsghdr *cmsg;
	325	size_t sizeof_fds = nb_fd * sizeof(int);
	326	char recv_fd[CMSG_SPACE(sizeof_fds)];
	327	struct msghdr msg;
	328	char dummy;
	329
	330	memset(&msg, 0, sizeof(msg));
	331
	332	/* Prepare to receive the structures */
	333	iov[0].iov_base = &dummy;
	334	iov[0].iov_len = 1;
	335	msg.msg_iov = iov;
	336	msg.msg_iovlen = 1;
	337	msg.msg_control = recv_fd;
	338	msg.msg_controllen = sizeof(recv_fd);
	339
	340	do {
	341	ret = recvmsg(sock, &msg, 0);
	342	} while (ret < 0 && errno == EINTR);
	343	if (ret < 0) {
	344	PERROR("recvmsg fds");
	345	goto end;
	346	}
	347	if (ret != 1) {
	348	fprintf(stderr, "Error: Received %zd bytes, expected %d\n",
	349	ret, 1);
	350	goto end;
	351	}
	352	if (msg.msg_flags & MSG_CTRUNC) {
	353	fprintf(stderr, "Error: Control message truncated.\n");
	354	ret = -1;
	355	goto end;
	356	}
	357	cmsg = CMSG_FIRSTHDR(&msg);
	358	if (!cmsg) {
	359	fprintf(stderr, "Error: Invalid control message header\n");
	360	ret = -1;
	361	goto end;
	362	}
	363	if (cmsg->cmsg_level != SOL_SOCKET \|\| cmsg->cmsg_type != SCM_RIGHTS) {
	364	fprintf(stderr, "Didn't received any fd\n");
	365	ret = -1;
	366	goto end;
	367	}
	368	if (cmsg->cmsg_len != CMSG_LEN(sizeof_fds)) {
	369	fprintf(stderr, "Error: Received %zu bytes of ancillary data, expected %zu\n",
	370	(size_t) cmsg->cmsg_len, (size_t) CMSG_LEN(sizeof_fds));
	371	ret = -1;
	372	goto end;
	373	}
	374	memcpy(fds, CMSG_DATA(cmsg), sizeof_fds);
	375	ret = sizeof_fds;
	376	end:
	377	return ret;
	378	}
	379
	380	/*
	381	* Send a message with credentials over a unix socket.
	382	*
	383	* Returns the size of data sent, or negative error value.
384	*/
90e535ef	385	LTTNG_HIDDEN
0d37f2bc DG	386	ssize_t lttcomm_send_creds_unix_sock(int sock, void *buf, size_t len)
	387	{
	388	struct msghdr msg;
	389	struct iovec iov[1];
	390	ssize_t ret = -1;
	391	#ifdef __linux__
	392	struct cmsghdr *cmptr;
	393	size_t sizeof_cred = sizeof(lttng_sock_cred);
	394	char anc_buf[CMSG_SPACE(sizeof_cred)];
	395	lttng_sock_cred *creds;
	396	#endif /* __linux__ */
	397
	398	memset(&msg, 0, sizeof(msg));
c617c0c6	399	memset(anc_buf, 0, CMSG_SPACE(sizeof_cred) * sizeof(char));
0d37f2bc DG	400
	401	iov[0].iov_base = buf;
	402	iov[0].iov_len = len;
	403	msg.msg_iov = iov;
	404	msg.msg_iovlen = 1;
	405
	406	#ifdef __linux__
	407	msg.msg_control = (caddr_t) anc_buf;
	408	msg.msg_controllen = CMSG_LEN(sizeof_cred);
	409
	410	cmptr = CMSG_FIRSTHDR(&msg);
	411	cmptr->cmsg_level = SOL_SOCKET;
	412	cmptr->cmsg_type = LTTNG_SOCK_CREDS;
	413	cmptr->cmsg_len = CMSG_LEN(sizeof_cred);
	414
	415	creds = (lttng_sock_cred*) CMSG_DATA(cmptr);
	416
	417	LTTNG_SOCK_SET_UID_CRED(creds, geteuid());
	418	LTTNG_SOCK_SET_GID_CRED(creds, getegid());
	419	LTTNG_SOCK_SET_PID_CRED(creds, getpid());
	420	#endif /* __linux__ */
	421
	422	do {
	423	ret = sendmsg(sock, &msg, 0);
	424	} while (ret < 0 && errno == EINTR);
	425	if (ret < 0) {
	426	/*
	427	* Only warn about EPIPE when quiet mode is deactivated.
	428	* We consider EPIPE as expected.
	429	*/
	430	if (errno != EPIPE \|\| !lttng_opt_quiet) {
	431	PERROR("sendmsg");
	432	}
	433	}
	434	return ret;
	435	}
	436
	437	/*
	438	* Recv a message accompanied with credentials from a unix socket.
	439	*
	440	* Returns the size of received data, or negative error value.
	441	*/
90e535ef	442	LTTNG_HIDDEN
0d37f2bc DG	443	ssize_t lttcomm_recv_creds_unix_sock(int sock, void *buf, size_t len,
	444	lttng_sock_cred *creds)
	445	{
	446	struct msghdr msg;
	447	struct iovec iov[1];
	448	ssize_t ret;
4100e49a	449	size_t len_last;
0d37f2bc DG	450	#ifdef __linux__
	451	struct cmsghdr *cmptr;
	452	size_t sizeof_cred = sizeof(lttng_sock_cred);
	453	char anc_buf[CMSG_SPACE(sizeof_cred)];
	454	#endif /* __linux__ */
	455
	456	memset(&msg, 0, sizeof(msg));
	457
	458	/* Not allowed */
	459	if (creds == NULL) {
	460	ret = -1;
	461	goto end;
	462	}
	463
	464	/* Prepare to receive the structures */
	465	iov[0].iov_base = buf;
	466	iov[0].iov_len = len;
	467	msg.msg_iov = iov;
	468	msg.msg_iovlen = 1;
	469
	470	#ifdef __linux__
	471	msg.msg_control = anc_buf;
	472	msg.msg_controllen = sizeof(anc_buf);
	473	#endif /* __linux__ */
	474
	475	do {
4100e49a	476	len_last = iov[0].iov_len;
0d37f2bc	477	ret = recvmsg(sock, &msg, 0);
4100e49a DG	478	if (ret > 0) {
	479	iov[0].iov_base += ret;
	480	iov[0].iov_len -= ret;
	481	assert(ret <= len_last);
	482	}
	483	} while ((ret > 0 && ret < len_last) \|\| (ret < 0 && errno == EINTR));
0d37f2bc DG	484	if (ret < 0) {
	485	PERROR("recvmsg fds");
	486	goto end;
4100e49a DG	487	} else if (ret > 0) {
4100e49a DG	488	ret = len;
0d37f2bc	489	}
4100e49a	490	/* Else ret = 0 meaning an orderly shutdown. */
0d37f2bc DG	491
	492	#ifdef __linux__
	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 != LTTNG_SOCK_CREDS) {
	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	(size_t) cmptr->cmsg_len, (size_t) CMSG_LEN(sizeof_cred));
	516	ret = -1;
	517	goto end;
	518	}
	519
	520	memcpy(creds, CMSG_DATA(cmptr), sizeof_cred);
	521	#elif (defined(__FreeBSD__) \|\| defined(__CYGWIN__))
	522	{
	523	int peer_ret;
	524
	525	peer_ret = getpeereid(sock, &creds->uid, &creds->gid);
	526	if (peer_ret != 0) {
	527	return peer_ret;
	528	}
	529	}
	530	#else
	531	#error "Please implement credential support for your OS."
	532	#endif /* __linux__ */
	533
	534	end:
	535	return ret;
	536	}
	537
	538	/*
	539	* Set socket option to use credentials passing.
	540	*/
	541	#ifdef __linux__
90e535ef	542	LTTNG_HIDDEN
0d37f2bc DG	543	int lttcomm_setsockopt_creds_unix_sock(int sock)
	544	{
	545	int ret, on = 1;
	546
	547	/* Set socket for credentials retrieval */
	548	ret = setsockopt(sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
	549	if (ret < 0) {
	550	PERROR("setsockopt creds unix sock");
	551	}
	552	return ret;
	553	}
	554	#elif (defined(__FreeBSD__) \|\| defined(__CYGWIN__))
90e535ef	555	LTTNG_HIDDEN
0d37f2bc DG	556	int lttcomm_setsockopt_creds_unix_sock(int sock)
	557	{
	558	return 0;
	559	}
	560	#else
	561	#error "Please implement credential support for your OS."
	562	#endif /* __linux__ */