[thirdparty/mdadm.git] / msg.c

/*
 * Copyright (C) 2008 Intel Corporation
 *
 * 	mdmon socket / message handling
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope 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 St - Fifth Floor, Boston, MA 02110-1301 USA.
 */
#ifndef _GNU_SOURCE
#define _GNU_SOURCE
#endif
#include <unistd.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <errno.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/un.h>
#include "mdadm.h"
#include "mdmon.h"

static const __u32 start_magic = 0x5a5aa5a5;
static const __u32 end_magic = 0xa5a55a5a;

static int send_buf(int fd, const void* buf, int len, int tmo)
{
	fd_set set;
	int rv;
	struct timeval timeout = {tmo, 0};
	struct timeval *ptmo = tmo ? &timeout : NULL;

	while (len) {
		FD_ZERO(&set);
		FD_SET(fd, &set);
		rv = select(fd+1, NULL, &set, NULL, ptmo);
		if (rv <= 0)
			return -1;
		rv = write(fd, buf, len);
		if (rv <= 0)
			return -1;
		len -= rv;
		buf += rv;
	}
	return 0;
}

static int recv_buf(int fd, void* buf, int len, int tmo)
{
	fd_set set;
	int rv;
	struct timeval timeout = {tmo, 0};
	struct timeval *ptmo = tmo ? &timeout : NULL;

	while (len) {
		FD_ZERO(&set);
		FD_SET(fd, &set);
		rv = select(fd+1, &set, NULL, NULL, ptmo);
		if (rv <= 0)
			return -1;
		rv = read(fd, buf, len);
		if (rv <= 0)
			return -1;
		len -= rv;
		buf += rv;
	}
	return 0;
}


int send_message(int fd, struct metadata_update *msg, int tmo)
{
	__s32 len = msg->len;
	int rv;

	rv = send_buf(fd, &start_magic, 4, tmo);
	rv = rv ?: send_buf(fd, &len, 4, tmo);
	if (len > 0)
		rv = rv ?: send_buf(fd, msg->buf, msg->len, tmo);
	rv = send_buf(fd, &end_magic, 4, tmo);

	return rv;
}

int receive_message(int fd, struct metadata_update *msg, int tmo)
{
	__u32 magic;
	__s32 len;
	int rv;

	rv = recv_buf(fd, &magic, 4, tmo);
	if (rv < 0 || magic != start_magic)
		return -1;
	rv = recv_buf(fd, &len, 4, tmo);
	if (rv < 0 || len > MSG_MAX_LEN)
		return -1;
	if (len > 0) {
		msg->buf = malloc(len);
		if (msg->buf == NULL)
			return -1;
		rv = recv_buf(fd, msg->buf, len, tmo);
		if (rv < 0) {
			free(msg->buf);
			return -1;
		}
	} else
		msg->buf = NULL;
	rv = recv_buf(fd, &magic, 4, tmo);
	if (rv < 0 || magic != end_magic) {
		free(msg->buf);
		return -1;
	}
	msg->len = len;
	return 0;
}

int ack(int fd, int tmo)
{
	struct metadata_update msg = { .len = 0 };

	return send_message(fd, &msg, tmo);
}

int wait_reply(int fd, int tmo)
{
	struct metadata_update msg;
	return receive_message(fd, &msg, tmo);
}

int connect_monitor(char *devname)
{
	char path[100];
	int sfd;
	long fl;
	struct sockaddr_un addr;
	int pos;
	char *c;

	pos = sprintf(path, "/var/run/mdadm/");
	if (is_subarray(devname)) {
		devname++;
		c = strchr(devname, '/');
		if (!c)
			return -1;
		snprintf(&path[pos], c - devname + 1, "%s", devname);
		pos += c - devname;
	} else
		pos += sprintf(&path[pos], "%s", devname);
	sprintf(&path[pos], ".sock");

	sfd = socket(PF_LOCAL, SOCK_STREAM, 0);
	if (sfd < 0)
		return -1;

	addr.sun_family = PF_LOCAL;
	strcpy(addr.sun_path, path);
	if (connect(sfd, &addr, sizeof(addr)) < 0) {
		close(sfd);
		return -1;
	}

	fl = fcntl(sfd, F_GETFL, 0);
	fl |= O_NONBLOCK;
	fcntl(sfd, F_SETFL, fl);

	return sfd;
}

int fping_monitor(int sfd)
{
	int err = 0;

	if (sfd < 0)
		return sfd;

	/* try to ping existing socket */
	if (ack(sfd, 20) != 0)
		err = -1;

	/* check the reply */
	if (!err && wait_reply(sfd, 20) != 0)
		err = -1;

	return err;
}


/* give the monitor a chance to update the metadata */
int ping_monitor(char *devname)
{
	int sfd = connect_monitor(devname);
	int err = fping_monitor(sfd);

	close(sfd);
	return err;
}

/* give the manager a chance to view the updated container state.  This
 * would naturally happen due to the manager noticing a change in
 * /proc/mdstat; however, pinging encourages this detection to happen
 * while an exclusive open() on the container is active
 */
int ping_manager(char *devname)
{
	int sfd = connect_monitor(devname);
	struct metadata_update msg = { .len = -1 };
	int err = 0;

	if (sfd < 0)
		return sfd;

	err = send_message(sfd, &msg, 20);

	/* check the reply */
	if (!err && wait_reply(sfd, 20) != 0)
		err = -1;

	close(sfd);
	return err;
}
Commit	Line	Data
f7dd881f DW	1	/*
	2	* Copyright (C) 2008 Intel Corporation
	3	*
	4	* mdmon socket / message handling
	5	*
	6	* This program is free software; you can redistribute it and/or modify it
	7	* under the terms and conditions of the GNU General Public License,
	8	* version 2, as published by the Free Software Foundation.
	9	*
	10	* This program is distributed in the hope it will be useful, but WITHOUT
	11	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	12	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
	13	* more details.
	14	*
	15	* You should have received a copy of the GNU General Public License along with
	16	* this program; if not, write to the Free Software Foundation, Inc.,
	17	* 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
	18	*/
	19	#ifndef _GNU_SOURCE
	20	#define _GNU_SOURCE
	21	#endif
	22	#include <unistd.h>
	23	#include <stdio.h>
	24	#include <string.h>
	25	#include <stdlib.h>
	26	#include <errno.h>
	27	#include <fcntl.h>
	28	#include <sys/types.h>
	29	#include <sys/socket.h>
	30	#include <sys/un.h>
	31	#include "mdadm.h"
bfa44e2e	32	#include "mdmon.h"
f7dd881f	33
bfa44e2e NB	34	static const __u32 start_magic = 0x5a5aa5a5;
	35	static const __u32 end_magic = 0xa5a55a5a;
	36
	37	static int send_buf(int fd, const void* buf, int len, int tmo)
f7dd881f	38	{
bfa44e2e NB	39	fd_set set;
	40	int rv;
	41	struct timeval timeout = {tmo, 0};
	42	struct timeval *ptmo = tmo ? &timeout : NULL;
	43
	44	while (len) {
	45	FD_ZERO(&set);
	46	FD_SET(fd, &set);
	47	rv = select(fd+1, NULL, &set, NULL, ptmo);
	48	if (rv <= 0)
	49	return -1;
	50	rv = write(fd, buf, len);
	51	if (rv <= 0)
	52	return -1;
	53	len -= rv;
	54	buf += rv;
	55	}
	56	return 0;
	57	}
f7dd881f	58
bfa44e2e NB	59	static int recv_buf(int fd, void* buf, int len, int tmo)
	60	{
	61	fd_set set;
	62	int rv;
	63	struct timeval timeout = {tmo, 0};
	64	struct timeval *ptmo = tmo ? &timeout : NULL;
	65
	66	while (len) {
	67	FD_ZERO(&set);
	68	FD_SET(fd, &set);
	69	rv = select(fd+1, &set, NULL, NULL, ptmo);
	70	if (rv <= 0)
	71	return -1;
	72	rv = read(fd, buf, len);
	73	if (rv <= 0)
	74	return -1;
	75	len -= rv;
	76	buf += rv;
	77	}
	78	return 0;
f7dd881f DW	79	}
	80
	81
bfa44e2e	82	int send_message(int fd, struct metadata_update *msg, int tmo)
f7dd881f	83	{
313a4a82	84	__s32 len = msg->len;
bfa44e2e NB	85	int rv;
	86
	87	rv = send_buf(fd, &start_magic, 4, tmo);
	88	rv = rv ?: send_buf(fd, &len, 4, tmo);
313a4a82	89	if (len > 0)
bfa44e2e NB	90	rv = rv ?: send_buf(fd, msg->buf, msg->len, tmo);
	91	rv = send_buf(fd, &end_magic, 4, tmo);
	92
	93	return rv;
f7dd881f DW	94	}
f7dd881f DW	95
bfa44e2e	96	int receive_message(int fd, struct metadata_update *msg, int tmo)
f7dd881f	97	{
bfa44e2e	98	__u32 magic;
313a4a82	99	__s32 len;
bfa44e2e NB	100	int rv;
	101
	102	rv = recv_buf(fd, &magic, 4, tmo);
	103	if (rv < 0 \|\| magic != start_magic)
	104	return -1;
	105	rv = recv_buf(fd, &len, 4, tmo);
	106	if (rv < 0 \|\| len > MSG_MAX_LEN)
f7dd881f	107	return -1;
313a4a82	108	if (len > 0) {
bfa44e2e NB	109	msg->buf = malloc(len);
	110	if (msg->buf == NULL)
	111	return -1;
	112	rv = recv_buf(fd, msg->buf, len, tmo);
	113	if (rv < 0) {
	114	free(msg->buf);
	115	return -1;
	116	}
	117	} else
	118	msg->buf = NULL;
	119	rv = recv_buf(fd, &magic, 4, tmo);
	120	if (rv < 0 \|\| magic != end_magic) {
	121	free(msg->buf);
	122	return -1;
	123	}
	124	msg->len = len;
	125	return 0;
f7dd881f DW	126	}
f7dd881f DW	127
bfa44e2e	128	int ack(int fd, int tmo)
f7dd881f	129	{
bfa44e2e	130	struct metadata_update msg = { .len = 0 };
f7dd881f DW	131
	132	return send_message(fd, &msg, tmo);
	133	}
	134
bfa44e2e	135	int wait_reply(int fd, int tmo)
f7dd881f	136	{
bfa44e2e NB	137	struct metadata_update msg;
bfa44e2e NB	138	return receive_message(fd, &msg, tmo);
f7dd881f DW	139	}
f7dd881f DW	140
f7dd881f DW	141	int connect_monitor(char *devname)
	142	{
	143	char path[100];
	144	int sfd;
	145	long fl;
	146	struct sockaddr_un addr;
c94709e8 DW	147	int pos;
	148	char *c;
	149
	150	pos = sprintf(path, "/var/run/mdadm/");
	151	if (is_subarray(devname)) {
	152	devname++;
	153	c = strchr(devname, '/');
	154	if (!c)
	155	return -1;
	156	snprintf(&path[pos], c - devname + 1, "%s", devname);
	157	pos += c - devname;
	158	} else
	159	pos += sprintf(&path[pos], "%s", devname);
	160	sprintf(&path[pos], ".sock");
f7dd881f	161
f7dd881f DW	162	sfd = socket(PF_LOCAL, SOCK_STREAM, 0);
	163	if (sfd < 0)
	164	return -1;
	165
	166	addr.sun_family = PF_LOCAL;
	167	strcpy(addr.sun_path, path);
	168	if (connect(sfd, &addr, sizeof(addr)) < 0) {
	169	close(sfd);
	170	return -1;
	171	}
	172
	173	fl = fcntl(sfd, F_GETFL, 0);
	174	fl \|= O_NONBLOCK;
	175	fcntl(sfd, F_SETFL, fl);
	176
	177	return sfd;
	178	}
	179
9f1da824	180	int fping_monitor(int sfd)
f7dd881f	181	{
f7dd881f DW	182	int err = 0;
	183
	184	if (sfd < 0)
	185	return sfd;
	186
	187	/* try to ping existing socket */
eb2c876f	188	if (ack(sfd, 20) != 0)
f7dd881f DW	189	err = -1;
	190
	191	/* check the reply */
eb2c876f	192	if (!err && wait_reply(sfd, 20) != 0)
f7dd881f DW	193	err = -1;
f7dd881f DW	194
9f1da824 DW	195	return err;
	196	}
	197
	198
	199	/* give the monitor a chance to update the metadata */
	200	int ping_monitor(char *devname)
	201	{
	202	int sfd = connect_monitor(devname);
	203	int err = fping_monitor(sfd);
	204
f7dd881f DW	205	close(sfd);
	206	return err;
	207	}
313a4a82 DW	208
	209	/* give the manager a chance to view the updated container state. This
	210	* would naturally happen due to the manager noticing a change in
	211	* /proc/mdstat; however, pinging encourages this detection to happen
	212	* while an exclusive open() on the container is active
	213	*/
	214	int ping_manager(char *devname)
	215	{
	216	int sfd = connect_monitor(devname);
	217	struct metadata_update msg = { .len = -1 };
	218	int err = 0;
	219
	220	if (sfd < 0)
	221	return sfd;
	222
	223	err = send_message(sfd, &msg, 20);
	224
	225	/* check the reply */
	226	if (!err && wait_reply(sfd, 20) != 0)
	227	err = -1;
	228
	229	close(sfd);
	230	return err;
	231	}