diff options
Diffstat (limited to 'msg.c')
| -rw-r--r-- | msg.c | 223 |
1 files changed, 223 insertions, 0 deletions
@@ -0,0 +1,223 @@ +/* + * 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; +} + +/* give the monitor a chance to update the metadata */ +int ping_monitor(char *devname) +{ + int sfd = connect_monitor(devname); + 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; + + 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; +} |