]> git.ipfire.org Git - thirdparty/mdadm.git/blame - msg.c
Merge branch 'master' into devel-3.0
[thirdparty/mdadm.git] / msg.c
CommitLineData
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
34static const __u32 start_magic = 0x5a5aa5a5;
35static const __u32 end_magic = 0xa5a55a5a;
36
37static 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
59static 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 82int 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}
95
bfa44e2e 96int 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}
127
bfa44e2e 128int 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 135int wait_reply(int fd, int tmo)
f7dd881f 136{
bfa44e2e
NB
137 struct metadata_update msg;
138 return receive_message(fd, &msg, tmo);
f7dd881f
DW
139}
140
f7dd881f
DW
141int 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
313a4a82 180/* give the monitor a chance to update the metadata */
f7dd881f
DW
181int ping_monitor(char *devname)
182{
183 int sfd = connect_monitor(devname);
f7dd881f
DW
184 int err = 0;
185
186 if (sfd < 0)
187 return sfd;
188
189 /* try to ping existing socket */
eb2c876f 190 if (ack(sfd, 20) != 0)
f7dd881f
DW
191 err = -1;
192
193 /* check the reply */
eb2c876f 194 if (!err && wait_reply(sfd, 20) != 0)
f7dd881f
DW
195 err = -1;
196
197 close(sfd);
198 return err;
199}
313a4a82
DW
200
201/* give the manager a chance to view the updated container state. This
202 * would naturally happen due to the manager noticing a change in
203 * /proc/mdstat; however, pinging encourages this detection to happen
204 * while an exclusive open() on the container is active
205 */
206int ping_manager(char *devname)
207{
208 int sfd = connect_monitor(devname);
209 struct metadata_update msg = { .len = -1 };
210 int err = 0;
211
212 if (sfd < 0)
213 return sfd;
214
215 err = send_message(sfd, &msg, 20);
216
217 /* check the reply */
218 if (!err && wait_reply(sfd, 20) != 0)
219 err = -1;
220
221 close(sfd);
222 return err;
223}