[lttng-tools.git] / src / common / 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 _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 <common/sessiond-comm/sessiond-comm.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 s_un;
	int fd, ret, closeret;

	if (strlen(pathname) >= sizeof(s_un.sun_path)) {
		ERR("unix socket address (\"%s\") is longer than the platform's limit (%zu > %zu).",
				pathname, strlen(pathname) + 1,
				sizeof(s_un.sun_path));
		ret = -ENAMETOOLONG;
		goto error;
	}

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

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

	ret = connect(fd, (struct sockaddr *) &s_un, sizeof(s_un));
	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 s_un;
	socklen_t len = sizeof(s_un);

	/* Blocking call */
	new_fd = accept(sock, (struct sockaddr *) &s_un, &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 s_un;
	int fd = -1;
	int ret = -1;

	if (strlen(pathname) >= sizeof(s_un.sun_path)) {
		ERR("unix socket address (\"%s\") is longer than the platform's limit (%zu > %zu).",
				pathname, strlen(pathname) + 1,
				sizeof(s_un.sun_path));
		ret = -ENAMETOOLONG;
		goto error;
	}

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

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

	/* Unlink the old file if present */
	(void) unlink(pathname);
	ret = bind(fd, (struct sockaddr *) &s_un, sizeof(s_un));
	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 = lttng_recvmsg_nosigpipe(sock, &msg);
		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;
}

/*
 * Receive data of size len in put that data into the buf param. Using recvmsg
 * API. Only use with sockets set in non-blocking mode.
 *
 * Return the size of received data.
 */
LTTNG_HIDDEN
ssize_t lttcomm_recv_unix_sock_non_block(int sock, void *buf, size_t len)
{
	struct msghdr msg;
	struct iovec iov[1];
	ssize_t ret;

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

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

retry:
	ret = lttng_recvmsg_nosigpipe(sock, &msg);
	if (ret < 0) {
		if (errno == EINTR) {
			goto retry;
		} else {
			/*
			 * Only warn about EPIPE when quiet mode is
			 * deactivated.
			 * We consider EPIPE as expected.
			 */
			if (errno != EPIPE || !lttng_opt_quiet) {
				PERROR("recvmsg");
			}
			goto end;
		}
	}
	ret = len;
end:
	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, const void *buf, size_t len)
{
	struct msghdr msg;
	struct iovec iov[1];
	ssize_t ret;

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

	iov[0].iov_base = (void *) buf;
	iov[0].iov_len = len;
	msg.msg_iov = iov;
	msg.msg_iovlen = 1;

	while (iov[0].iov_len) {
		ret = sendmsg(sock, &msg, 0);
		if (ret < 0) {
			if (errno == EINTR) {
				continue;
			} else {
				/*
				 * Only warn about EPIPE when quiet mode is
				 * deactivated.
				 * We consider EPIPE as expected.
				 */
				if (errno != EPIPE || !lttng_opt_quiet) {
					PERROR("sendmsg");
				}
				goto end;
			}
		}
		iov[0].iov_len -= ret;
		iov[0].iov_base += ret;
	}
	ret = len;
end:
	return ret;
}

/*
 * Send buf data of size len. Using sendmsg API.
 * Only use with non-blocking sockets. The difference with the blocking version
 * of the function is that this one does not retry to send on partial sends,
 * except if the interruption was caused by a signal (EINTR).
 *
 * Return the size of sent data.
 */
LTTNG_HIDDEN
ssize_t lttcomm_send_unix_sock_non_block(int sock, const void *buf, size_t len)
{
	struct msghdr msg;
	struct iovec iov[1];
	ssize_t ret;

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

	iov[0].iov_base = (void *) buf;
	iov[0].iov_len = len;
	msg.msg_iov = iov;
	msg.msg_iovlen = 1;

retry:
	ret = sendmsg(sock, &msg, 0);
	if (ret < 0) {
		if (errno == EINTR) {
			goto retry;
		} else {
			/*
			 * Only warn about EPIPE when quiet mode is
			 * deactivated.
			 * We consider EPIPE as expected.
			 */
			if (errno != EPIPE || !lttng_opt_quiet) {
				PERROR("sendmsg");
			}
			goto end;
		}
	}
	ret = len;
end:
	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, const 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, sizeof(tmp));

	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);
	if (!cmptr) {
		return -1;
	}

	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);

#ifdef __linux__
/* Account for the struct ucred cmsg in the buffer size */
#define LTTNG_SOCK_RECV_FDS_BUF_SIZE CMSG_SPACE(sizeof_fds) + CMSG_SPACE(sizeof(struct ucred))
#else
#define LTTNG_SOCK_RECV_FDS_BUF_SIZE CMSG_SPACE(sizeof_fds)
#endif /* __linux__ */

	char recv_buf[LTTNG_SOCK_RECV_FDS_BUF_SIZE];
	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;

	cmsg = (struct cmsghdr *) recv_buf;
	cmsg->cmsg_len = CMSG_LEN(sizeof_fds);
	cmsg->cmsg_level = SOL_SOCKET;
	cmsg->cmsg_type = SCM_RIGHTS;

	msg.msg_control = cmsg;
	msg.msg_controllen = CMSG_LEN(sizeof(recv_buf));
	msg.msg_flags = 0;

	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;
	}

	/*
	 * If the socket was configured with SO_PASSCRED, the kernel will add a
	 * control message (cmsg) to the ancillary data of the unix socket. We
	 * need to expect a cmsg of the SCM_CREDENTIALS as the first control
	 * message.
	 */
	for (cmsg = CMSG_FIRSTHDR(&msg); cmsg != NULL; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
		if (cmsg->cmsg_level != SOL_SOCKET) {
			fprintf(stderr, "Error: The socket needs to be of type SOL_SOCKET\n");
			ret = -1;
			goto end;
		}
		if (cmsg->cmsg_type == SCM_RIGHTS) {
			/*
			 * We found the controle message for file descriptors,
			 * now copy the fds to the fds ptr and return success.
			 */
			if (cmsg->cmsg_len != CMSG_LEN(sizeof_fds)) {
				fprintf(stderr, "Error: Received %zu bytes of"
					"ancillary data for FDs, 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;
			goto end;
		}
#ifdef __linux__
		if (cmsg->cmsg_type == SCM_CREDENTIALS) {
			/*
			 * Expect credentials to be sent when expecting fds even
			 * if no credential were include in the send(). The
			 * kernel adds them...
			 */
			ret = -1;
		}
#endif /* __linux__ */
	}
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;

	memset(anc_buf, 0, CMSG_SPACE(sizeof_cred) * sizeof(char));
#endif /* __linux__ */

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

	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);
	if (!cmptr) {
		return -1;
	}
	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__) || defined(__sun__) || defined(__APPLE__))
	{
		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__) || defined(__sun__) || defined(__APPLE__))
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
6c1c0768	19	#define _LGPL_SOURCE
0d37f2bc DG	20	#include <assert.h>
	21	#include <limits.h>
	22	#include <stdio.h>
	23	#include <stdlib.h>
	24	#include <string.h>
	25	#include <sys/stat.h>
	26	#include <sys/types.h>
	27	#include <unistd.h>
	28	#include <errno.h>
	29
90e535ef	30	#include <common/common.h>
2038dd6c	31	#include <common/sessiond-comm/sessiond-comm.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)
0d37f2bc DG	40	{
665886a6	41	struct sockaddr_un s_un;
0d37f2bc DG	42	int fd, ret, closeret;
0d37f2bc DG	43
7f8bf467 JG	44	if (strlen(pathname) >= sizeof(s_un.sun_path)) {
	45	ERR("unix socket address (\"%s\") is longer than the platform's limit (%zu > %zu).",
	46	pathname, strlen(pathname) + 1,
	47	sizeof(s_un.sun_path));
	48	ret = -ENAMETOOLONG;
	49	goto error;
	50	}
	51
0d37f2bc DG	52	fd = socket(PF_UNIX, SOCK_STREAM, 0);
	53	if (fd < 0) {
	54	PERROR("socket");
	55	ret = fd;
	56	goto error;
	57	}
	58
665886a6 MJ	59	memset(&s_un, 0, sizeof(s_un));
	60	s_un.sun_family = AF_UNIX;
	61	strncpy(s_un.sun_path, pathname, sizeof(s_un.sun_path));
	62	s_un.sun_path[sizeof(s_un.sun_path) - 1] = '\0';
0d37f2bc	63
665886a6	64	ret = connect(fd, (struct sockaddr *) &s_un, sizeof(s_un));
0d37f2bc DG	65	if (ret < 0) {
	66	/*
	67	* Don't print message on connect error, because connect is used in
	68	* normal execution to detect if sessiond is alive.
	69	*/
	70	goto error_connect;
	71	}
	72
	73	return fd;
	74
	75	error_connect:
	76	closeret = close(fd);
	77	if (closeret) {
	78	PERROR("close");
	79	}
	80	error:
	81	return ret;
	82	}
	83
	84	/*
	85	* Do an accept(2) on the sock and return the new file descriptor. The socket
	86	* MUST be bind(2) before.
	87	*/
90e535ef	88	LTTNG_HIDDEN
0d37f2bc DG	89	int lttcomm_accept_unix_sock(int sock)
	90	{
	91	int new_fd;
665886a6	92	struct sockaddr_un s_un;
50786a72	93	socklen_t len = sizeof(s_un);
0d37f2bc DG	94
0d37f2bc DG	95	/* Blocking call */
665886a6	96	new_fd = accept(sock, (struct sockaddr *) &s_un, &len);
0d37f2bc DG	97	if (new_fd < 0) {
	98	PERROR("accept");
	99	}
	100
	101	return new_fd;
	102	}
	103
7567352f MD	104	LTTNG_HIDDEN
	105	int lttcomm_create_anon_unix_socketpair(int *fds)
	106	{
	107	if (socketpair(PF_UNIX, SOCK_STREAM, 0, fds) < 0) {
	108	PERROR("socketpair");
	109	return -1;
	110	}
	111	return 0;
	112	}
	113
0d37f2bc DG	114	/*
	115	* Creates a AF_UNIX local socket using pathname bind the socket upon creation
	116	* and return the fd.
	117	*/
90e535ef	118	LTTNG_HIDDEN
0d37f2bc DG	119	int lttcomm_create_unix_sock(const char *pathname)
0d37f2bc DG	120	{
665886a6	121	struct sockaddr_un s_un;
7f8bf467	122	int fd = -1;
0d37f2bc DG	123	int ret = -1;
0d37f2bc DG	124
7f8bf467 JG	125	if (strlen(pathname) >= sizeof(s_un.sun_path)) {
	126	ERR("unix socket address (\"%s\") is longer than the platform's limit (%zu > %zu).",
	127	pathname, strlen(pathname) + 1,
	128	sizeof(s_un.sun_path));
	129	ret = -ENAMETOOLONG;
	130	goto error;
	131	}
	132
0d37f2bc DG	133	/* Create server socket */
	134	if ((fd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0) {
	135	PERROR("socket");
	136	goto error;
	137	}
	138
665886a6 MJ	139	memset(&s_un, 0, sizeof(s_un));
	140	s_un.sun_family = AF_UNIX;
	141	strncpy(s_un.sun_path, pathname, sizeof(s_un.sun_path));
	142	s_un.sun_path[sizeof(s_un.sun_path) - 1] = '\0';
0d37f2bc DG	143
	144	/* Unlink the old file if present */
	145	(void) unlink(pathname);
665886a6	146	ret = bind(fd, (struct sockaddr *) &s_un, sizeof(s_un));
0d37f2bc DG	147	if (ret < 0) {
	148	PERROR("bind");
	149	goto error;
	150	}
	151
	152	return fd;
	153
	154	error:
17e75273 DG	155	if (fd >= 0) {
	156	if (close(fd) < 0) {
	157	PERROR("close create unix sock");
	158	}
	159	}
0d37f2bc DG	160	return ret;
	161	}
	162
	163	/*
	164	* Make the socket listen using LTTNG_SESSIOND_COMM_MAX_LISTEN.
	165	*/
90e535ef	166	LTTNG_HIDDEN
0d37f2bc DG	167	int lttcomm_listen_unix_sock(int sock)
	168	{
	169	int ret;
	170
	171	ret = listen(sock, LTTNG_SESSIOND_COMM_MAX_LISTEN);
	172	if (ret < 0) {
	173	PERROR("listen");
	174	}
	175
	176	return ret;
	177	}
	178
	179	/*
	180	* Receive data of size len in put that data into the buf param. Using recvmsg
	181	* API.
	182	*
	183	* Return the size of received data.
	184	*/
90e535ef	185	LTTNG_HIDDEN
0d37f2bc DG	186	ssize_t lttcomm_recv_unix_sock(int sock, void *buf, size_t len)
	187	{
	188	struct msghdr msg;
	189	struct iovec iov[1];
	190	ssize_t ret = -1;
7c5aef62	191	size_t len_last;
0d37f2bc DG	192
	193	memset(&msg, 0, sizeof(msg));
	194
	195	iov[0].iov_base = buf;
	196	iov[0].iov_len = len;
	197	msg.msg_iov = iov;
	198	msg.msg_iovlen = 1;
	199
	200	do {
7c5aef62	201	len_last = iov[0].iov_len;
fbb1fd3a	202	ret = lttng_recvmsg_nosigpipe(sock, &msg);
7c5aef62 DG	203	if (ret > 0) {
	204	iov[0].iov_base += ret;
	205	iov[0].iov_len -= ret;
	206	assert(ret <= len_last);
	207	}
	208	} while ((ret > 0 && ret < len_last) \|\| (ret < 0 && errno == EINTR));
0d37f2bc DG	209	if (ret < 0) {
0d37f2bc DG	210	PERROR("recvmsg");
7c5aef62 DG	211	} else if (ret > 0) {
7c5aef62 DG	212	ret = len;
0d37f2bc	213	}
7c5aef62	214	/* Else ret = 0 meaning an orderly shutdown. */
0d37f2bc DG	215
	216	return ret;
	217	}
	218
c72435ad JG	219	/*
	220	* Receive data of size len in put that data into the buf param. Using recvmsg
	221	* API. Only use with sockets set in non-blocking mode.
	222	*
	223	* Return the size of received data.
	224	*/
	225	LTTNG_HIDDEN
	226	ssize_t lttcomm_recv_unix_sock_non_block(int sock, void *buf, size_t len)
	227	{
	228	struct msghdr msg;
	229	struct iovec iov[1];
	230	ssize_t ret;
	231
	232	memset(&msg, 0, sizeof(msg));
	233
	234	iov[0].iov_base = buf;
	235	iov[0].iov_len = len;
	236	msg.msg_iov = iov;
	237	msg.msg_iovlen = 1;
	238
	239	retry:
	240	ret = lttng_recvmsg_nosigpipe(sock, &msg);
	241	if (ret < 0) {
	242	if (errno == EINTR) {
	243	goto retry;
	244	} else {
	245	/*
	246	* Only warn about EPIPE when quiet mode is
	247	* deactivated.
	248	* We consider EPIPE as expected.
	249	*/
	250	if (errno != EPIPE \|\| !lttng_opt_quiet) {
	251	PERROR("recvmsg");
	252	}
	253	goto end;
	254	}
	255	}
	256	ret = len;
	257	end:
	258	return ret;
	259	}
	260
0d37f2bc DG	261	/*
	262	* Send buf data of size len. Using sendmsg API.
	263	*
	264	* Return the size of sent data.
	265	*/
90e535ef	266	LTTNG_HIDDEN
c2d69327	267	ssize_t lttcomm_send_unix_sock(int sock, const void *buf, size_t len)
0d37f2bc DG	268	{
	269	struct msghdr msg;
	270	struct iovec iov[1];
c72435ad	271	ssize_t ret;
0d37f2bc DG	272
	273	memset(&msg, 0, sizeof(msg));
	274
c2d69327	275	iov[0].iov_base = (void *) buf;
0d37f2bc DG	276	iov[0].iov_len = len;
	277	msg.msg_iov = iov;
	278	msg.msg_iovlen = 1;
	279
c72435ad JG	280	while (iov[0].iov_len) {
	281	ret = sendmsg(sock, &msg, 0);
	282	if (ret < 0) {
	283	if (errno == EINTR) {
	284	continue;
	285	} else {
	286	/*
	287	* Only warn about EPIPE when quiet mode is
	288	* deactivated.
	289	* We consider EPIPE as expected.
	290	*/
	291	if (errno != EPIPE \|\| !lttng_opt_quiet) {
	292	PERROR("sendmsg");
	293	}
	294	goto end;
	295	}
	296	}
	297	iov[0].iov_len -= ret;
	298	iov[0].iov_base += ret;
	299	}
	300	ret = len;
	301	end:
	302	return ret;
	303	}
	304
	305	/*
	306	* Send buf data of size len. Using sendmsg API.
	307	* Only use with non-blocking sockets. The difference with the blocking version
	308	* of the function is that this one does not retry to send on partial sends,
	309	* except if the interruption was caused by a signal (EINTR).
	310	*
	311	* Return the size of sent data.
	312	*/
	313	LTTNG_HIDDEN
	314	ssize_t lttcomm_send_unix_sock_non_block(int sock, const void *buf, size_t len)
	315	{
	316	struct msghdr msg;
	317	struct iovec iov[1];
	318	ssize_t ret;
	319
	320	memset(&msg, 0, sizeof(msg));
	321
	322	iov[0].iov_base = (void *) buf;
	323	iov[0].iov_len = len;
	324	msg.msg_iov = iov;
	325	msg.msg_iovlen = 1;
	326
	327	retry:
0d37f2bc DG	328	ret = sendmsg(sock, &msg, 0);
0d37f2bc DG	329	if (ret < 0) {
c72435ad JG	330	if (errno == EINTR) {
	331	goto retry;
	332	} else {
	333	/*
	334	* Only warn about EPIPE when quiet mode is
	335	* deactivated.
	336	* We consider EPIPE as expected.
	337	*/
	338	if (errno != EPIPE \|\| !lttng_opt_quiet) {
	339	PERROR("sendmsg");
	340	}
	341	goto end;
0d37f2bc DG	342	}
0d37f2bc DG	343	}
c72435ad JG	344	ret = len;
c72435ad JG	345	end:
0d37f2bc DG	346	return ret;
	347	}
	348
	349	/*
	350	* Shutdown cleanly a unix socket.
	351	*/
90e535ef	352	LTTNG_HIDDEN
0d37f2bc DG	353	int lttcomm_close_unix_sock(int sock)
	354	{
	355	int ret, closeret;
	356
	357	/* Shutdown receptions and transmissions */
	358	ret = shutdown(sock, SHUT_RDWR);
	359	if (ret < 0) {
	360	PERROR("shutdown");
	361	}
	362
	363	closeret = close(sock);
	364	if (closeret) {
	365	PERROR("close");
	366	}
	367
	368	return ret;
	369	}
	370
	371	/*
	372	* Send a message accompanied by fd(s) over a unix socket.
	373	*
	374	* Returns the size of data sent, or negative error value.
	375	*/
90e535ef	376	LTTNG_HIDDEN
ac2f30af	377	ssize_t lttcomm_send_fds_unix_sock(int sock, const int *fds, size_t nb_fd)
0d37f2bc DG	378	{
	379	struct msghdr msg;
	380	struct cmsghdr *cmptr;
	381	struct iovec iov[1];
	382	ssize_t ret = -1;
	383	unsigned int sizeof_fds = nb_fd * sizeof(int);
	384	char tmp[CMSG_SPACE(sizeof_fds)];
	385	char dummy = 0;
	386
	387	memset(&msg, 0, sizeof(msg));
b3f35e02	388	memset(tmp, 0, sizeof(tmp));
0d37f2bc DG	389
	390	if (nb_fd > LTTCOMM_MAX_SEND_FDS)
	391	return -EINVAL;
	392
	393	msg.msg_control = (caddr_t)tmp;
	394	msg.msg_controllen = CMSG_LEN(sizeof_fds);
	395
	396	cmptr = CMSG_FIRSTHDR(&msg);
1d8d0328 MJ	397	if (!cmptr) {
	398	return -1;
	399	}
b3f35e02	400
0d37f2bc DG	401	cmptr->cmsg_level = SOL_SOCKET;
	402	cmptr->cmsg_type = SCM_RIGHTS;
	403	cmptr->cmsg_len = CMSG_LEN(sizeof_fds);
	404	memcpy(CMSG_DATA(cmptr), fds, sizeof_fds);
	405	/* Sum of the length of all control messages in the buffer: */
	406	msg.msg_controllen = cmptr->cmsg_len;
	407
	408	iov[0].iov_base = &dummy;
	409	iov[0].iov_len = 1;
	410	msg.msg_iov = iov;
	411	msg.msg_iovlen = 1;
	412
	413	do {
	414	ret = sendmsg(sock, &msg, 0);
	415	} while (ret < 0 && errno == EINTR);
	416	if (ret < 0) {
	417	/*
	418	* Only warn about EPIPE when quiet mode is deactivated.
	419	* We consider EPIPE as expected.
	420	*/
	421	if (errno != EPIPE \|\| !lttng_opt_quiet) {
	422	PERROR("sendmsg");
	423	}
	424	}
	425	return ret;
	426	}
	427
	428	/*
	429	* Recv a message accompanied by fd(s) from a unix socket.
	430	*
	431	* Returns the size of received data, or negative error value.
	432	*
	433	* Expect at most "nb_fd" file descriptors. Returns the number of fd
	434	* actually received in nb_fd.
	435	*/
90e535ef	436	LTTNG_HIDDEN
0d37f2bc DG	437	ssize_t lttcomm_recv_fds_unix_sock(int sock, int *fds, size_t nb_fd)
	438	{
	439	struct iovec iov[1];
	440	ssize_t ret = 0;
	441	struct cmsghdr *cmsg;
	442	size_t sizeof_fds = nb_fd * sizeof(int);
b3f35e02	443
6380c001 MJ	444	#ifdef __linux__
	445	/* Account for the struct ucred cmsg in the buffer size */
	446	#define LTTNG_SOCK_RECV_FDS_BUF_SIZE CMSG_SPACE(sizeof_fds) + CMSG_SPACE(sizeof(struct ucred))
	447	#else
	448	#define LTTNG_SOCK_RECV_FDS_BUF_SIZE CMSG_SPACE(sizeof_fds)
	449	#endif /* __linux__ */
	450
	451	char recv_buf[LTTNG_SOCK_RECV_FDS_BUF_SIZE];
0d37f2bc DG	452	struct msghdr msg;
	453	char dummy;
	454
	455	memset(&msg, 0, sizeof(msg));
	456
	457	/* Prepare to receive the structures */
	458	iov[0].iov_base = &dummy;
	459	iov[0].iov_len = 1;
	460	msg.msg_iov = iov;
	461	msg.msg_iovlen = 1;
b3f35e02 FD	462
	463	cmsg = (struct cmsghdr *) recv_buf;
	464	cmsg->cmsg_len = CMSG_LEN(sizeof_fds);
	465	cmsg->cmsg_level = SOL_SOCKET;
	466	cmsg->cmsg_type = SCM_RIGHTS;
	467
	468	msg.msg_control = cmsg;
	469	msg.msg_controllen = CMSG_LEN(sizeof(recv_buf));
	470	msg.msg_flags = 0;
0d37f2bc DG	471
	472	do {
	473	ret = recvmsg(sock, &msg, 0);
	474	} while (ret < 0 && errno == EINTR);
	475	if (ret < 0) {
	476	PERROR("recvmsg fds");
	477	goto end;
	478	}
b3f35e02	479
0d37f2bc DG	480	if (ret != 1) {
	481	fprintf(stderr, "Error: Received %zd bytes, expected %d\n",
	482	ret, 1);
	483	goto end;
	484	}
b3f35e02	485
0d37f2bc DG	486	if (msg.msg_flags & MSG_CTRUNC) {
	487	fprintf(stderr, "Error: Control message truncated.\n");
	488	ret = -1;
	489	goto end;
	490	}
b3f35e02 FD	491
	492	/*
	493	* If the socket was configured with SO_PASSCRED, the kernel will add a
	494	* control message (cmsg) to the ancillary data of the unix socket. We
	495	* need to expect a cmsg of the SCM_CREDENTIALS as the first control
	496	* message.
	497	*/
	498	for (cmsg = CMSG_FIRSTHDR(&msg); cmsg != NULL; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
b3f35e02 FD	499	if (cmsg->cmsg_level != SOL_SOCKET) {
	500	fprintf(stderr, "Error: The socket needs to be of type SOL_SOCKET\n");
	501	ret = -1;
	502	goto end;
	503	}
	504	if (cmsg->cmsg_type == SCM_RIGHTS) {
	505	/*
	506	* We found the controle message for file descriptors,
	507	* now copy the fds to the fds ptr and return success.
	508	*/
	509	if (cmsg->cmsg_len != CMSG_LEN(sizeof_fds)) {
	510	fprintf(stderr, "Error: Received %zu bytes of"
	511	"ancillary data for FDs, expected %zu\n",
	512	(size_t) cmsg->cmsg_len,
	513	(size_t) CMSG_LEN(sizeof_fds));
	514	ret = -1;
	515	goto end;
	516	}
	517	memcpy(fds, CMSG_DATA(cmsg), sizeof_fds);
	518	ret = sizeof_fds;
	519	goto end;
	520	}
6380c001	521	#ifdef __linux__
b3f35e02 FD	522	if (cmsg->cmsg_type == SCM_CREDENTIALS) {
	523	/*
	524	* Expect credentials to be sent when expecting fds even
	525	* if no credential were include in the send(). The
	526	* kernel adds them...
	527	*/
b3f35e02 FD	528	ret = -1;
b3f35e02 FD	529	}
6380c001	530	#endif /* __linux__ */
0d37f2bc	531	}
0d37f2bc DG	532	end:
	533	return ret;
	534	}
	535
	536	/*
	537	* Send a message with credentials over a unix socket.
	538	*
	539	* Returns the size of data sent, or negative error value.
	540	*/
90e535ef	541	LTTNG_HIDDEN
0d37f2bc DG	542	ssize_t lttcomm_send_creds_unix_sock(int sock, void *buf, size_t len)
	543	{
	544	struct msghdr msg;
	545	struct iovec iov[1];
	546	ssize_t ret = -1;
	547	#ifdef __linux__
	548	struct cmsghdr *cmptr;
	549	size_t sizeof_cred = sizeof(lttng_sock_cred);
	550	char anc_buf[CMSG_SPACE(sizeof_cred)];
	551	lttng_sock_cred *creds;
8bbffd54 MJ	552
8bbffd54 MJ	553	memset(anc_buf, 0, CMSG_SPACE(sizeof_cred) * sizeof(char));
0d37f2bc DG	554	#endif /* __linux__ */
	555
	556	memset(&msg, 0, sizeof(msg));
	557
	558	iov[0].iov_base = buf;
	559	iov[0].iov_len = len;
	560	msg.msg_iov = iov;
	561	msg.msg_iovlen = 1;
	562
	563	#ifdef __linux__
	564	msg.msg_control = (caddr_t) anc_buf;
	565	msg.msg_controllen = CMSG_LEN(sizeof_cred);
	566
	567	cmptr = CMSG_FIRSTHDR(&msg);
1d8d0328 MJ	568	if (!cmptr) {
	569	return -1;
	570	}
0d37f2bc DG	571	cmptr->cmsg_level = SOL_SOCKET;
	572	cmptr->cmsg_type = LTTNG_SOCK_CREDS;
	573	cmptr->cmsg_len = CMSG_LEN(sizeof_cred);
	574
	575	creds = (lttng_sock_cred*) CMSG_DATA(cmptr);
	576
	577	LTTNG_SOCK_SET_UID_CRED(creds, geteuid());
	578	LTTNG_SOCK_SET_GID_CRED(creds, getegid());
	579	LTTNG_SOCK_SET_PID_CRED(creds, getpid());
	580	#endif /* __linux__ */
	581
	582	do {
	583	ret = sendmsg(sock, &msg, 0);
	584	} while (ret < 0 && errno == EINTR);
	585	if (ret < 0) {
	586	/*
	587	* Only warn about EPIPE when quiet mode is deactivated.
	588	* We consider EPIPE as expected.
	589	*/
	590	if (errno != EPIPE \|\| !lttng_opt_quiet) {
	591	PERROR("sendmsg");
	592	}
	593	}
	594	return ret;
	595	}
	596
	597	/*
	598	* Recv a message accompanied with credentials from a unix socket.
	599	*
	600	* Returns the size of received data, or negative error value.
	601	*/
90e535ef	602	LTTNG_HIDDEN
0d37f2bc DG	603	ssize_t lttcomm_recv_creds_unix_sock(int sock, void *buf, size_t len,
	604	lttng_sock_cred *creds)
	605	{
	606	struct msghdr msg;
	607	struct iovec iov[1];
	608	ssize_t ret;
4100e49a	609	size_t len_last;
0d37f2bc DG	610	#ifdef __linux__
	611	struct cmsghdr *cmptr;
	612	size_t sizeof_cred = sizeof(lttng_sock_cred);
	613	char anc_buf[CMSG_SPACE(sizeof_cred)];
	614	#endif /* __linux__ */
	615
	616	memset(&msg, 0, sizeof(msg));
	617
	618	/* Not allowed */
	619	if (creds == NULL) {
	620	ret = -1;
	621	goto end;
	622	}
	623
	624	/* Prepare to receive the structures */
	625	iov[0].iov_base = buf;
	626	iov[0].iov_len = len;
	627	msg.msg_iov = iov;
	628	msg.msg_iovlen = 1;
	629
	630	#ifdef __linux__
	631	msg.msg_control = anc_buf;
	632	msg.msg_controllen = sizeof(anc_buf);
	633	#endif /* __linux__ */
	634
	635	do {
4100e49a	636	len_last = iov[0].iov_len;
0d37f2bc	637	ret = recvmsg(sock, &msg, 0);
4100e49a DG	638	if (ret > 0) {
	639	iov[0].iov_base += ret;
	640	iov[0].iov_len -= ret;
	641	assert(ret <= len_last);
	642	}
	643	} while ((ret > 0 && ret < len_last) \|\| (ret < 0 && errno == EINTR));
0d37f2bc DG	644	if (ret < 0) {
	645	PERROR("recvmsg fds");
	646	goto end;
4100e49a DG	647	} else if (ret > 0) {
4100e49a DG	648	ret = len;
0d37f2bc	649	}
4100e49a	650	/* Else ret = 0 meaning an orderly shutdown. */
0d37f2bc DG	651
	652	#ifdef __linux__
	653	if (msg.msg_flags & MSG_CTRUNC) {
	654	fprintf(stderr, "Error: Control message truncated.\n");
	655	ret = -1;
	656	goto end;
	657	}
	658
	659	cmptr = CMSG_FIRSTHDR(&msg);
	660	if (cmptr == NULL) {
	661	fprintf(stderr, "Error: Invalid control message header\n");
	662	ret = -1;
	663	goto end;
	664	}
	665
	666	if (cmptr->cmsg_level != SOL_SOCKET \|\|
	667	cmptr->cmsg_type != LTTNG_SOCK_CREDS) {
	668	fprintf(stderr, "Didn't received any credentials\n");
	669	ret = -1;
	670	goto end;
	671	}
	672
	673	if (cmptr->cmsg_len != CMSG_LEN(sizeof_cred)) {
	674	fprintf(stderr, "Error: Received %zu bytes of ancillary data, expected %zu\n",
	675	(size_t) cmptr->cmsg_len, (size_t) CMSG_LEN(sizeof_cred));
	676	ret = -1;
	677	goto end;
	678	}
	679
	680	memcpy(creds, CMSG_DATA(cmptr), sizeof_cred);
bfa419e4	681	#elif (defined(__FreeBSD__) \|\| defined(__CYGWIN__) \|\| defined(__sun__) \|\| defined(__APPLE__))
0d37f2bc DG	682	{
	683	int peer_ret;
	684
	685	peer_ret = getpeereid(sock, &creds->uid, &creds->gid);
	686	if (peer_ret != 0) {
	687	return peer_ret;
	688	}
	689	}
	690	#else
	691	#error "Please implement credential support for your OS."
	692	#endif /* __linux__ */
	693
	694	end:
	695	return ret;
	696	}
	697
	698	/*
	699	* Set socket option to use credentials passing.
	700	*/
	701	#ifdef __linux__
90e535ef	702	LTTNG_HIDDEN
0d37f2bc DG	703	int lttcomm_setsockopt_creds_unix_sock(int sock)
	704	{
	705	int ret, on = 1;
	706
	707	/* Set socket for credentials retrieval */
	708	ret = setsockopt(sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
	709	if (ret < 0) {
	710	PERROR("setsockopt creds unix sock");
	711	}
	712	return ret;
	713	}
bfa419e4	714	#elif (defined(__FreeBSD__) \|\| defined(__CYGWIN__) \|\| defined(__sun__) \|\| defined(__APPLE__))
90e535ef	715	LTTNG_HIDDEN
0d37f2bc DG	716	int lttcomm_setsockopt_creds_unix_sock(int sock)
	717	{
	718	return 0;
	719	}
	720	#else
	721	#error "Please implement credential support for your OS."
	722	#endif /* __linux__ */