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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"
enum tx_rx_state {
TX_RX_START,
TX_RX_SEQ,
TX_RX_NUM_BYTES,
TX_RX_BUF,
TX_RX_END,
TX_RX_SUCCESS,
TX_RX_ERR,
};
const int start_magic = 0x5a5aa5a5;
const int end_magic = 0xa5a55a5a;
#define txrx(fd, buf, size, flags) (recv_send ? \
recv(fd, buf, size, flags) : \
send(fd, buf, size, flags))
/* non-blocking send/receive with n second timeout */
static enum tx_rx_state
tx_rx_message(int fd, struct md_message *msg, int recv_send, int tmo)
{
int d = recv_send ? 0 : start_magic;
int flags = recv_send ? 0 : MSG_NOSIGNAL;
enum tx_rx_state state = TX_RX_START;
void *buf = &d;
size_t size = sizeof(d);
off_t n = 0;
int rc;
int again;
do {
again = 0;
rc = txrx(fd, buf + n, size - n, flags);
if (rc <= 0) { /* error */
if (rc == -1 && errno == EAGAIN)
again = 1;
else
state = TX_RX_ERR;
} else if (rc + n == size) /* done */
switch (state) {
case TX_RX_START:
if (recv_send && d != start_magic)
state = TX_RX_ERR;
else {
state = TX_RX_SEQ;
buf = &msg->seq;
size = sizeof(msg->seq);
n = 0;
}
break;
case TX_RX_SEQ:
state = TX_RX_NUM_BYTES;
buf = &msg->num_bytes;
size = sizeof(msg->num_bytes);
n = 0;
break;
case TX_RX_NUM_BYTES:
if (msg->num_bytes >
sizeof(union md_message_commands))
state = TX_RX_ERR;
else if (recv_send && msg->num_bytes) {
msg->buf = malloc(msg->num_bytes);
if (!msg->buf)
state = TX_RX_ERR;
else {
state = TX_RX_BUF;
buf = msg->buf;
size = msg->num_bytes;
n = 0;
}
} else if (!recv_send && msg->num_bytes) {
state = TX_RX_BUF;
buf = msg->buf;
size = msg->num_bytes;
n = 0;
} else {
d = recv_send ? 0 : end_magic;
state = TX_RX_END;
buf = &d;
size = sizeof(d);
n = 0;
}
break;
case TX_RX_BUF:
d = recv_send ? 0 : end_magic;
state = TX_RX_END;
buf = &d;
size = sizeof(d);
n = 0;
break;
case TX_RX_END:
if (recv_send && d != end_magic)
state = TX_RX_ERR;
else
state = TX_RX_SUCCESS;
break;
case TX_RX_ERR:
case TX_RX_SUCCESS:
break;
}
else /* continue */
n += rc;
if (again) {
fd_set set;
struct timeval timeout = { tmo, 0 };
struct timeval *ptmo = tmo ? &timeout : NULL;
FD_ZERO(&set);
FD_SET(fd, &set);
if (recv_send)
rc = select(fd + 1, &set, NULL, NULL, ptmo);
else
rc = select(fd + 1, NULL, &set, NULL, ptmo);
if (rc <= 0)
state = TX_RX_ERR;
}
} while (state < TX_RX_SUCCESS);
return state;
}
int receive_message(int fd, struct md_message *msg, int tmo)
{
if (tx_rx_message(fd, msg, 1, tmo) == TX_RX_SUCCESS)
return 0;
else
return -1;
}
int send_message(int fd, struct md_message *msg, int tmo)
{
if (tx_rx_message(fd, msg, 0, tmo) == TX_RX_SUCCESS)
return 0;
else
return -1;
}
int ack(int fd, int seq, int tmo)
{
struct md_message msg = { .seq = seq, .num_bytes = 0 };
return send_message(fd, &msg, tmo);
}
int nack(int fd, int err, int tmo)
{
struct md_message msg = { .seq = err, .num_bytes = 0 };
return send_message(fd, &msg, tmo);
}
int send_remove_device(int fd, dev_t rdev, int seq, int tmo)
{
struct md_remove_device_cmd cmd = { .action = md_action_remove_device,
.rdev = rdev
};
struct md_message msg = { .seq = seq,
.num_bytes = sizeof(cmd),
.buf = &cmd
};
return send_message(fd, &msg, tmo);
}
int connect_monitor(char *devname)
{
char path[100];
int sfd;
long fl;
struct sockaddr_un addr;
sprintf(path, "/var/run/mdadm/%s.sock", devname);
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 ping_monitor(char *devname)
{
int sfd = connect_monitor(devname);
struct md_message msg;
int err = 0;
if (sfd < 0)
return sfd;
/* try to ping existing socket */
if (ack(sfd, 0, 0) != 0)
err = -1;
/* check the reply */
if (!err && receive_message(sfd, &msg, 0) != 0)
err = -1;
if (msg.seq != 0)
err = -1;
close(sfd);
return err;
}
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