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/*
* 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;
}
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