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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" | |
32 | ||
33 | enum tx_rx_state { | |
34 | TX_RX_START, | |
35 | TX_RX_SEQ, | |
36 | TX_RX_NUM_BYTES, | |
37 | TX_RX_BUF, | |
38 | TX_RX_END, | |
39 | TX_RX_SUCCESS, | |
40 | TX_RX_ERR, | |
41 | }; | |
42 | ||
43 | const int start_magic = 0x5a5aa5a5; | |
44 | const int end_magic = 0xa5a55a5a; | |
45 | ||
46 | #define txrx(fd, buf, size, flags) (recv_send ? \ | |
47 | recv(fd, buf, size, flags) : \ | |
48 | send(fd, buf, size, flags)) | |
49 | ||
50 | /* non-blocking send/receive with n second timeout */ | |
51 | static enum tx_rx_state | |
52 | tx_rx_message(int fd, struct md_message *msg, int recv_send, int tmo) | |
53 | { | |
54 | int d = recv_send ? 0 : start_magic; | |
55 | int flags = recv_send ? 0 : MSG_NOSIGNAL; | |
56 | enum tx_rx_state state = TX_RX_START; | |
57 | void *buf = &d; | |
58 | size_t size = sizeof(d); | |
59 | off_t n = 0; | |
60 | int rc; | |
61 | int again; | |
62 | ||
63 | do { | |
64 | again = 0; | |
65 | rc = txrx(fd, buf + n, size - n, flags); | |
66 | if (rc <= 0) { /* error */ | |
67 | if (rc == -1 && errno == EAGAIN) | |
68 | again = 1; | |
69 | else | |
70 | state = TX_RX_ERR; | |
71 | } else if (rc + n == size) /* done */ | |
72 | switch (state) { | |
73 | case TX_RX_START: | |
74 | if (recv_send && d != start_magic) | |
75 | state = TX_RX_ERR; | |
76 | else { | |
77 | state = TX_RX_SEQ; | |
78 | buf = &msg->seq; | |
79 | size = sizeof(msg->seq); | |
80 | n = 0; | |
81 | } | |
82 | break; | |
83 | case TX_RX_SEQ: | |
84 | state = TX_RX_NUM_BYTES; | |
85 | buf = &msg->num_bytes; | |
86 | size = sizeof(msg->num_bytes); | |
87 | n = 0; | |
88 | break; | |
89 | case TX_RX_NUM_BYTES: | |
90 | if (msg->num_bytes > | |
91 | sizeof(union md_message_commands)) | |
92 | state = TX_RX_ERR; | |
93 | else if (recv_send && msg->num_bytes) { | |
94 | msg->buf = malloc(msg->num_bytes); | |
95 | if (!msg->buf) | |
96 | state = TX_RX_ERR; | |
97 | else { | |
98 | state = TX_RX_BUF; | |
99 | buf = msg->buf; | |
100 | size = msg->num_bytes; | |
101 | n = 0; | |
102 | } | |
103 | } else if (!recv_send && msg->num_bytes) { | |
104 | state = TX_RX_BUF; | |
105 | buf = msg->buf; | |
106 | size = msg->num_bytes; | |
107 | n = 0; | |
108 | } else { | |
109 | d = recv_send ? 0 : end_magic; | |
110 | state = TX_RX_END; | |
111 | buf = &d; | |
112 | size = sizeof(d); | |
113 | n = 0; | |
114 | } | |
115 | break; | |
116 | case TX_RX_BUF: | |
117 | d = recv_send ? 0 : end_magic; | |
118 | state = TX_RX_END; | |
119 | buf = &d; | |
120 | size = sizeof(d); | |
121 | n = 0; | |
122 | break; | |
123 | case TX_RX_END: | |
124 | if (recv_send && d != end_magic) | |
125 | state = TX_RX_ERR; | |
126 | else | |
127 | state = TX_RX_SUCCESS; | |
128 | break; | |
129 | case TX_RX_ERR: | |
130 | case TX_RX_SUCCESS: | |
131 | break; | |
132 | } | |
133 | else /* continue */ | |
134 | n += rc; | |
135 | ||
136 | if (again) { | |
137 | fd_set set; | |
138 | struct timeval timeout = { tmo, 0 }; | |
139 | struct timeval *ptmo = tmo ? &timeout : NULL; | |
140 | ||
141 | FD_ZERO(&set); | |
142 | FD_SET(fd, &set); | |
143 | ||
144 | if (recv_send) | |
145 | rc = select(fd + 1, &set, NULL, NULL, ptmo); | |
146 | else | |
147 | rc = select(fd + 1, NULL, &set, NULL, ptmo); | |
148 | ||
149 | if (rc <= 0) | |
150 | state = TX_RX_ERR; | |
151 | } | |
152 | } while (state < TX_RX_SUCCESS); | |
153 | ||
154 | return state; | |
155 | } | |
156 | ||
157 | ||
158 | int receive_message(int fd, struct md_message *msg, int tmo) | |
159 | { | |
160 | if (tx_rx_message(fd, msg, 1, tmo) == TX_RX_SUCCESS) | |
161 | return 0; | |
162 | else | |
163 | return -1; | |
164 | } | |
165 | ||
166 | int send_message(int fd, struct md_message *msg, int tmo) | |
167 | { | |
168 | if (tx_rx_message(fd, msg, 0, tmo) == TX_RX_SUCCESS) | |
169 | return 0; | |
170 | else | |
171 | return -1; | |
172 | } | |
173 | ||
174 | int ack(int fd, int seq, int tmo) | |
175 | { | |
176 | struct md_message msg = { .seq = seq, .num_bytes = 0 }; | |
177 | ||
178 | return send_message(fd, &msg, tmo); | |
179 | } | |
180 | ||
181 | int nack(int fd, int err, int tmo) | |
182 | { | |
183 | struct md_message msg = { .seq = err, .num_bytes = 0 }; | |
184 | ||
185 | return send_message(fd, &msg, tmo); | |
186 | } | |
187 | ||
188 | int send_remove_device(int fd, dev_t rdev, int seq, int tmo) | |
189 | { | |
190 | struct md_remove_device_cmd cmd = { .action = md_action_remove_device, | |
191 | .rdev = rdev | |
192 | }; | |
193 | struct md_message msg = { .seq = seq, | |
194 | .num_bytes = sizeof(cmd), | |
195 | .buf = &cmd | |
196 | }; | |
197 | ||
198 | return send_message(fd, &msg, tmo); | |
199 | } | |
200 | ||
201 | int connect_monitor(char *devname) | |
202 | { | |
203 | char path[100]; | |
204 | int sfd; | |
205 | long fl; | |
206 | struct sockaddr_un addr; | |
207 | ||
208 | sprintf(path, "/var/run/mdadm/%s.sock", devname); | |
209 | sfd = socket(PF_LOCAL, SOCK_STREAM, 0); | |
210 | if (sfd < 0) | |
211 | return -1; | |
212 | ||
213 | addr.sun_family = PF_LOCAL; | |
214 | strcpy(addr.sun_path, path); | |
215 | if (connect(sfd, &addr, sizeof(addr)) < 0) { | |
216 | close(sfd); | |
217 | return -1; | |
218 | } | |
219 | ||
220 | fl = fcntl(sfd, F_GETFL, 0); | |
221 | fl |= O_NONBLOCK; | |
222 | fcntl(sfd, F_SETFL, fl); | |
223 | ||
224 | return sfd; | |
225 | } | |
226 | ||
227 | int ping_monitor(char *devname) | |
228 | { | |
229 | int sfd = connect_monitor(devname); | |
230 | struct md_message msg; | |
231 | int err = 0; | |
232 | ||
233 | if (sfd < 0) | |
234 | return sfd; | |
235 | ||
236 | /* try to ping existing socket */ | |
237 | if (ack(sfd, 0, 0) != 0) | |
238 | err = -1; | |
239 | ||
240 | /* check the reply */ | |
241 | if (!err && receive_message(sfd, &msg, 0) != 0) | |
242 | err = -1; | |
243 | ||
244 | if (msg.seq != 0) | |
245 | err = -1; | |
246 | ||
247 | close(sfd); | |
248 | return err; | |
249 | } |