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Commit | Line | Data |
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549e9569 NB |
1 | |
2 | /* | |
3 | * md array manager. | |
4 | * When md arrays have user-space managed metadata, this is the program | |
5 | * that does the managing. | |
6 | * | |
7 | * Given one argument: the name of the array (e.g. /dev/md0) that is | |
8 | * the container. | |
9 | * We fork off a helper that runs high priority and mlocked. It responds to | |
10 | * device failures and other events that might stop writeout, or that are | |
11 | * trivial to deal with. | |
12 | * The main thread then watches for new arrays being created in the container | |
13 | * and starts monitoring them too ... along with a few other tasks. | |
14 | * | |
15 | * The main thread communicates with the priority thread by writing over | |
16 | * a pipe. | |
17 | * Separate programs can communicate with the main thread via Unix-domain | |
18 | * socket. | |
19 | * The two threads share address space and open file table. | |
20 | * | |
21 | */ | |
22 | ||
23 | #ifndef _GNU_SOURCE | |
24 | #define _GNU_SOURCE | |
25 | #endif | |
26 | ||
27 | #include <unistd.h> | |
28 | #include <stdlib.h> | |
4d43913c | 29 | #include <sys/types.h> |
549e9569 NB |
30 | #include <sys/stat.h> |
31 | #include <sys/socket.h> | |
32 | #include <sys/un.h> | |
33 | #include <sys/mman.h> | |
4d43913c | 34 | #include <sys/syscall.h> |
9fe32043 | 35 | #include <sys/wait.h> |
549e9569 NB |
36 | #include <stdio.h> |
37 | #include <errno.h> | |
38 | #include <string.h> | |
39 | #include <fcntl.h> | |
b109d928 | 40 | #include <signal.h> |
549e9569 NB |
41 | |
42 | #include <sched.h> | |
43 | ||
44 | #include "mdadm.h" | |
45 | #include "mdmon.h" | |
46 | ||
549e9569 NB |
47 | struct active_array *discard_this; |
48 | struct active_array *pending_discard; | |
4d43913c NB |
49 | |
50 | int mon_tid, mgr_tid; | |
549e9569 NB |
51 | |
52 | int run_child(void *v) | |
53 | { | |
54 | struct supertype *c = v; | |
1ed3f387 | 55 | |
549e9569 NB |
56 | do_monitor(c); |
57 | return 0; | |
58 | } | |
59 | ||
60 | int clone_monitor(struct supertype *container) | |
61 | { | |
549e9569 | 62 | static char stack[4096]; |
549e9569 | 63 | |
2cc98f9e | 64 | mon_tid = clone(run_child, stack+4096-64, |
549e9569 NB |
65 | CLONE_FS|CLONE_FILES|CLONE_VM|CLONE_SIGHAND|CLONE_THREAD, |
66 | container); | |
3e70c845 | 67 | |
4d43913c | 68 | mgr_tid = syscall(SYS_gettid); |
2cc98f9e DW |
69 | |
70 | return mon_tid; | |
549e9569 NB |
71 | } |
72 | ||
73 | static struct superswitch *find_metadata_methods(char *vers) | |
74 | { | |
75 | if (strcmp(vers, "ddf") == 0) | |
76 | return &super_ddf; | |
5b65005f DW |
77 | if (strcmp(vers, "imsm") == 0) |
78 | return &super_imsm; | |
549e9569 NB |
79 | return NULL; |
80 | } | |
81 | ||
82 | ||
295646b3 | 83 | int make_pidfile(char *devname, int o_excl) |
549e9569 NB |
84 | { |
85 | char path[100]; | |
86 | char pid[10]; | |
87 | int fd; | |
88 | sprintf(path, "/var/run/mdadm/%s.pid", devname); | |
89 | ||
b109d928 | 90 | fd = open(path, O_RDWR|O_CREAT|o_excl, 0600); |
549e9569 | 91 | if (fd < 0) |
295646b3 | 92 | return -errno; |
549e9569 NB |
93 | sprintf(pid, "%d\n", getpid()); |
94 | write(fd, pid, strlen(pid)); | |
95 | close(fd); | |
96 | return 0; | |
97 | } | |
98 | ||
b109d928 DW |
99 | static void try_kill_monitor(char *devname) |
100 | { | |
101 | char buf[100]; | |
102 | int fd; | |
103 | pid_t pid; | |
104 | ||
105 | sprintf(buf, "/var/run/mdadm/%s.pid", devname); | |
106 | fd = open(buf, O_RDONLY); | |
107 | if (fd < 0) | |
108 | return; | |
109 | ||
110 | if (read(fd, buf, sizeof(buf)) < 0) { | |
111 | close(fd); | |
112 | return; | |
113 | } | |
114 | ||
115 | close(fd); | |
116 | pid = strtoul(buf, NULL, 10); | |
117 | ||
118 | /* kill this process if it is mdmon */ | |
119 | sprintf(buf, "/proc/%lu/cmdline", (unsigned long) pid); | |
120 | fd = open(buf, O_RDONLY); | |
121 | if (fd < 0) | |
122 | return; | |
123 | ||
124 | if (read(fd, buf, sizeof(buf)) < 0) { | |
125 | close(fd); | |
126 | return; | |
127 | } | |
128 | ||
129 | if (strstr(buf, "mdmon") != NULL) | |
130 | kill(pid, SIGTERM); | |
131 | } | |
132 | ||
e0d6609f NB |
133 | void remove_pidfile(char *devname) |
134 | { | |
135 | char buf[100]; | |
136 | ||
137 | sprintf(buf, "/var/run/mdadm/%s.pid", devname); | |
138 | unlink(buf); | |
57752795 N |
139 | sprintf(buf, "/var/run/mdadm/%s.sock", devname); |
140 | unlink(buf); | |
e0d6609f NB |
141 | } |
142 | ||
295646b3 | 143 | int make_control_sock(char *devname) |
549e9569 NB |
144 | { |
145 | char path[100]; | |
146 | int sfd; | |
147 | long fl; | |
148 | struct sockaddr_un addr; | |
149 | ||
150 | sprintf(path, "/var/run/mdadm/%s.sock", devname); | |
151 | unlink(path); | |
152 | sfd = socket(PF_LOCAL, SOCK_STREAM, 0); | |
153 | if (sfd < 0) | |
154 | return -1; | |
155 | ||
156 | addr.sun_family = PF_LOCAL; | |
157 | strcpy(addr.sun_path, path); | |
158 | if (bind(sfd, &addr, sizeof(addr)) < 0) { | |
159 | close(sfd); | |
160 | return -1; | |
161 | } | |
162 | listen(sfd, 10); | |
163 | fl = fcntl(sfd, F_GETFL, 0); | |
164 | fl |= O_NONBLOCK; | |
165 | fcntl(sfd, F_SETFL, fl); | |
166 | return sfd; | |
167 | } | |
168 | ||
295646b3 DW |
169 | int socket_hup_requested; |
170 | static void hup(int sig) | |
171 | { | |
172 | socket_hup_requested = 1; | |
173 | } | |
174 | ||
4d43913c NB |
175 | static void wake_me(int sig) |
176 | { | |
177 | ||
178 | } | |
179 | ||
16ddab0d DW |
180 | /* if we are debugging and starting mdmon by hand then don't fork */ |
181 | static int do_fork(void) | |
182 | { | |
183 | #ifdef DEBUG | |
184 | if (env_no_mdmon()) | |
185 | return 0; | |
186 | #endif | |
187 | ||
188 | return 1; | |
189 | } | |
190 | ||
191 | ||
192 | ||
549e9569 NB |
193 | int main(int argc, char *argv[]) |
194 | { | |
195 | int mdfd; | |
549e9569 NB |
196 | struct mdinfo *mdi, *di; |
197 | struct supertype *container; | |
4d43913c | 198 | sigset_t set; |
bfa44e2e | 199 | struct sigaction act; |
9fe32043 N |
200 | int pfd[2]; |
201 | int status; | |
4d43913c | 202 | |
549e9569 NB |
203 | if (argc != 2) { |
204 | fprintf(stderr, "Usage: md-manage /device/name/for/container\n"); | |
205 | exit(2); | |
206 | } | |
207 | mdfd = open(argv[1], O_RDWR); | |
208 | if (mdfd < 0) { | |
209 | fprintf(stderr, "md-manage: %s: %s\n", argv[1], | |
210 | strerror(errno)); | |
211 | exit(1); | |
212 | } | |
213 | if (md_get_version(mdfd) < 0) { | |
214 | fprintf(stderr, "md-manage: %s: Not an md device\n", | |
215 | argv[1]); | |
216 | exit(1); | |
217 | } | |
218 | ||
9fe32043 | 219 | /* Fork, and have the child tell us when they are ready */ |
16ddab0d DW |
220 | if (do_fork()) { |
221 | pipe(pfd); | |
222 | switch(fork()) { | |
223 | case -1: | |
224 | fprintf(stderr, "mdmon: failed to fork: %s\n", | |
225 | strerror(errno)); | |
226 | exit(1); | |
227 | case 0: /* child */ | |
228 | close(pfd[0]); | |
229 | break; | |
230 | default: /* parent */ | |
231 | close(pfd[1]); | |
232 | if (read(pfd[0], &status, sizeof(status)) != sizeof(status)) { | |
233 | wait(&status); | |
234 | status = WEXITSTATUS(status); | |
235 | } | |
236 | exit(status); | |
9fe32043 | 237 | } |
16ddab0d DW |
238 | } else |
239 | pfd[0] = pfd[1] = -1; | |
549e9569 NB |
240 | /* hopefully it is a container - we'll check later */ |
241 | ||
242 | container = malloc(sizeof(*container)); | |
549e9569 NB |
243 | container->devnum = fd2devnum(mdfd); |
244 | container->devname = devnum2devname(container->devnum); | |
e0d6609f | 245 | container->device_name = argv[1]; |
549e9569 NB |
246 | |
247 | /* If this fails, we hope it already exists */ | |
248 | mkdir("/var/run/mdadm", 0600); | |
249 | /* pid file lives in /var/run/mdadm/mdXX.pid */ | |
b109d928 DW |
250 | if (make_pidfile(container->devname, O_EXCL) < 0) { |
251 | if (ping_monitor(container->devname) == 0) { | |
252 | fprintf(stderr, "mdmon: %s already managed\n", | |
253 | container->devname); | |
254 | exit(3); | |
255 | } else { | |
295646b3 DW |
256 | int err; |
257 | ||
b109d928 DW |
258 | /* cleanup the old monitor, this one is taking over */ |
259 | try_kill_monitor(container->devname); | |
295646b3 DW |
260 | err = make_pidfile(container->devname, 0); |
261 | if (err < 0) { | |
b109d928 DW |
262 | fprintf(stderr, "mdmon: %s Cannot create pidfile\n", |
263 | container->devname); | |
295646b3 DW |
264 | if (err == -EROFS) { |
265 | /* FIXME implement a mechanism to | |
266 | * prevent duplicate monitor instances | |
267 | */ | |
268 | fprintf(stderr, | |
269 | "mdmon: continuing on read-only file system\n"); | |
270 | } else | |
271 | exit(3); | |
b109d928 DW |
272 | } |
273 | } | |
549e9569 NB |
274 | } |
275 | ||
276 | container->sock = make_control_sock(container->devname); | |
295646b3 | 277 | if (container->sock < 0) |
549e9569 | 278 | fprintf(stderr, "mdmon: Cannot create socket in /var/run/mdadm\n"); |
549e9569 NB |
279 | container->arrays = NULL; |
280 | ||
281 | mdi = sysfs_read(mdfd, container->devnum, | |
282 | GET_VERSION|GET_LEVEL|GET_DEVS); | |
283 | ||
284 | if (!mdi) { | |
285 | fprintf(stderr, "mdmon: failed to load sysfs info for %s\n", | |
286 | container->devname); | |
287 | exit(3); | |
288 | } | |
289 | if (mdi->array.level != UnSet) { | |
290 | fprintf(stderr, "mdmon: %s is not a container - cannot monitor\n", | |
291 | argv[1]); | |
292 | exit(3); | |
293 | } | |
294 | if (mdi->array.major_version != -1 || | |
295 | mdi->array.minor_version != -2) { | |
296 | fprintf(stderr, "mdmon: %s does not use external metadata - cannot monitor\n", | |
297 | argv[1]); | |
298 | exit(3); | |
299 | } | |
300 | ||
301 | container->ss = find_metadata_methods(mdi->text_version); | |
302 | if (container->ss == NULL) { | |
303 | fprintf(stderr, "mdmon: %s uses unknown metadata: %s\n", | |
304 | argv[1], mdi->text_version); | |
305 | exit(3); | |
306 | } | |
307 | ||
308 | container->devs = NULL; | |
309 | for (di = mdi->devs; di; di = di->next) { | |
310 | struct mdinfo *cd = malloc(sizeof(*cd)); | |
7bc1962f | 311 | *cd = *di; |
549e9569 NB |
312 | cd->next = container->devs; |
313 | container->devs = cd; | |
314 | } | |
315 | sysfs_free(mdi); | |
316 | ||
317 | ||
318 | if (container->ss->load_super(container, mdfd, argv[1])) { | |
319 | fprintf(stderr, "mdmon: Cannot load metadata for %s\n", | |
320 | argv[1]); | |
321 | exit(3); | |
322 | } | |
549e9569 | 323 | |
9fe32043 N |
324 | /* Ok, this is close enough. We can say goodbye to our parent now. |
325 | */ | |
326 | status = 0; | |
327 | write(pfd[1], &status, sizeof(status)); | |
328 | close(pfd[1]); | |
329 | ||
330 | chdir("/"); | |
331 | setsid(); | |
332 | close(0); | |
333 | open("/dev/null", O_RDWR); | |
334 | close(1); | |
335 | dup(0); | |
336 | #ifndef DEBUG | |
337 | close(2); | |
338 | dup(0); | |
339 | #endif | |
340 | ||
549e9569 NB |
341 | mlockall(MCL_FUTURE); |
342 | ||
4d43913c NB |
343 | /* SIGUSR is sent between parent and child. So both block it |
344 | * and enable it only with pselect. | |
345 | */ | |
346 | sigemptyset(&set); | |
347 | sigaddset(&set, SIGUSR1); | |
295646b3 | 348 | sigaddset(&set, SIGHUP); |
4d43913c | 349 | sigprocmask(SIG_BLOCK, &set, NULL); |
bfa44e2e NB |
350 | act.sa_handler = wake_me; |
351 | act.sa_flags = 0; | |
352 | sigaction(SIGUSR1, &act, NULL); | |
295646b3 DW |
353 | act.sa_handler = hup; |
354 | sigaction(SIGHUP, &act, NULL); | |
bfa44e2e NB |
355 | act.sa_handler = SIG_IGN; |
356 | sigaction(SIGPIPE, &act, NULL); | |
4d43913c | 357 | |
3e70c845 | 358 | if (clone_monitor(container) < 0) { |
295646b3 | 359 | fprintf(stderr, "mdmon: failed to start monitor process: %s\n", |
549e9569 NB |
360 | strerror(errno)); |
361 | exit(2); | |
362 | } | |
363 | ||
364 | do_manager(container); | |
365 | ||
366 | exit(0); | |
367 | } |