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CommitLineData
a54d5262
DW
1/*
2 * mdmon - monitor external metadata arrays
3 *
e736b623
N
4 * Copyright (C) 2007-2009 Neil Brown <neilb@suse.de>
5 * Copyright (C) 2007-2009 Intel Corporation
a54d5262
DW
6 *
7 * This program is free software; you can redistribute it and/or modify it
8 * under the terms and conditions of the GNU General Public License,
9 * version 2, as published by the Free Software Foundation.
10 *
11 * This program is distributed in the hope it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
14 * more details.
15 *
16 * You should have received a copy of the GNU General Public License along with
17 * this program; if not, write to the Free Software Foundation, Inc.,
18 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
19 */
549e9569
NB
20
21/*
22 * md array manager.
23 * When md arrays have user-space managed metadata, this is the program
24 * that does the managing.
25 *
26 * Given one argument: the name of the array (e.g. /dev/md0) that is
27 * the container.
28 * We fork off a helper that runs high priority and mlocked. It responds to
29 * device failures and other events that might stop writeout, or that are
30 * trivial to deal with.
31 * The main thread then watches for new arrays being created in the container
32 * and starts monitoring them too ... along with a few other tasks.
33 *
34 * The main thread communicates with the priority thread by writing over
35 * a pipe.
36 * Separate programs can communicate with the main thread via Unix-domain
37 * socket.
38 * The two threads share address space and open file table.
39 *
40 */
41
42#ifndef _GNU_SOURCE
43#define _GNU_SOURCE
44#endif
45
46#include <unistd.h>
47#include <stdlib.h>
4d43913c 48#include <sys/types.h>
549e9569
NB
49#include <sys/stat.h>
50#include <sys/socket.h>
51#include <sys/un.h>
52#include <sys/mman.h>
4d43913c 53#include <sys/syscall.h>
9fe32043 54#include <sys/wait.h>
549e9569
NB
55#include <stdio.h>
56#include <errno.h>
57#include <string.h>
58#include <fcntl.h>
b109d928 59#include <signal.h>
13047e4c 60#include <dirent.h>
549e9569
NB
61
62#include <sched.h>
63
64#include "mdadm.h"
65#include "mdmon.h"
66
549e9569
NB
67struct active_array *discard_this;
68struct active_array *pending_discard;
4d43913c
NB
69
70int mon_tid, mgr_tid;
549e9569 71
6144ed44
DW
72int sigterm;
73
549e9569
NB
74int run_child(void *v)
75{
76 struct supertype *c = v;
1ed3f387 77
549e9569
NB
78 do_monitor(c);
79 return 0;
80}
81
97f734fd
N
82#ifdef __ia64__
83int __clone2(int (*fn)(void *),
84 void *child_stack_base, size_t stack_size,
85 int flags, void *arg, ...
86 /* pid_t *pid, struct user_desc *tls, pid_t *ctid */ );
87#endif
88 int clone_monitor(struct supertype *container)
549e9569 89{
549e9569 90 static char stack[4096];
549e9569 91
97f734fd
N
92#ifdef __ia64__
93 mon_tid = __clone2(run_child, stack, sizeof(stack),
94 CLONE_FS|CLONE_FILES|CLONE_VM|CLONE_SIGHAND|CLONE_THREAD,
95 container);
96#else
2cc98f9e 97 mon_tid = clone(run_child, stack+4096-64,
549e9569
NB
98 CLONE_FS|CLONE_FILES|CLONE_VM|CLONE_SIGHAND|CLONE_THREAD,
99 container);
97f734fd 100#endif
3e70c845 101
4d43913c 102 mgr_tid = syscall(SYS_gettid);
2cc98f9e
DW
103
104 return mon_tid;
549e9569
NB
105}
106
ce744c97
DW
107static struct superswitch *find_metadata_methods(char *vers)
108{
109 if (strcmp(vers, "ddf") == 0)
110 return &super_ddf;
111 if (strcmp(vers, "imsm") == 0)
112 return &super_imsm;
113 return NULL;
114}
115
96a8270d
DW
116static int test_pidfile(char *devname)
117{
118 char path[100];
119 struct stat st;
120
121 sprintf(path, "/var/run/mdadm/%s.pid", devname);
122 return stat(path, &st);
123}
549e9569 124
295646b3 125int make_pidfile(char *devname, int o_excl)
549e9569
NB
126{
127 char path[100];
128 char pid[10];
129 int fd;
3d2c4fc7
DW
130 int n;
131
6144ed44
DW
132 if (sigterm)
133 return -1;
134
549e9569
NB
135 sprintf(path, "/var/run/mdadm/%s.pid", devname);
136
b109d928 137 fd = open(path, O_RDWR|O_CREAT|o_excl, 0600);
549e9569 138 if (fd < 0)
295646b3 139 return -errno;
549e9569 140 sprintf(pid, "%d\n", getpid());
3d2c4fc7 141 n = write(fd, pid, strlen(pid));
549e9569 142 close(fd);
3d2c4fc7
DW
143 if (n < 0)
144 return -errno;
549e9569
NB
145 return 0;
146}
147
883a6142
DW
148int is_container_member(struct mdstat_ent *mdstat, char *container)
149{
150 if (mdstat->metadata_version == NULL ||
151 strncmp(mdstat->metadata_version, "external:", 9) != 0 ||
152 !is_subarray(mdstat->metadata_version+9) ||
153 strncmp(mdstat->metadata_version+10, container, strlen(container)) != 0 ||
154 mdstat->metadata_version[10+strlen(container)] != '/')
155 return 0;
156
157 return 1;
158}
159
96a8270d 160pid_t devname2mdmon(char *devname)
b109d928
DW
161{
162 char buf[100];
96a8270d 163 pid_t pid = -1;
b109d928 164 int fd;
b109d928
DW
165
166 sprintf(buf, "/var/run/mdadm/%s.pid", devname);
96a8270d 167 fd = open(buf, O_RDONLY|O_NOATIME);
b109d928 168 if (fd < 0)
96a8270d 169 return -1;
b109d928 170
96a8270d
DW
171 if (read(fd, buf, sizeof(buf)) > 0)
172 sscanf(buf, "%d\n", &pid);
b109d928 173 close(fd);
96a8270d
DW
174
175 return pid;
176}
177
9f1da824 178static void try_kill_monitor(pid_t pid, char *devname, int sock)
96a8270d
DW
179{
180 char buf[100];
181 int fd;
182 struct mdstat_ent *mdstat;
b109d928 183
8aae4219
DW
184 /* first rule of survival... don't off yourself */
185 if (pid == getpid())
186 return;
187
b109d928
DW
188 /* kill this process if it is mdmon */
189 sprintf(buf, "/proc/%lu/cmdline", (unsigned long) pid);
190 fd = open(buf, O_RDONLY);
191 if (fd < 0)
192 return;
193
194 if (read(fd, buf, sizeof(buf)) < 0) {
195 close(fd);
196 return;
197 }
198
883a6142
DW
199 if (!strstr(buf, "mdmon"))
200 return;
201
202 kill(pid, SIGTERM);
203
204 mdstat = mdstat_read(0, 0);
205 for ( ; mdstat; mdstat = mdstat->next)
206 if (is_container_member(mdstat, devname)) {
207 sprintf(buf, "/dev/%s", mdstat->dev);
9f1da824 208 WaitClean(buf, sock, 0);
883a6142
DW
209 }
210 free_mdstat(mdstat);
b109d928
DW
211}
212
e0d6609f
NB
213void remove_pidfile(char *devname)
214{
215 char buf[100];
216
6144ed44
DW
217 if (sigterm)
218 return;
219
e0d6609f
NB
220 sprintf(buf, "/var/run/mdadm/%s.pid", devname);
221 unlink(buf);
57752795
N
222 sprintf(buf, "/var/run/mdadm/%s.sock", devname);
223 unlink(buf);
e0d6609f
NB
224}
225
295646b3 226int make_control_sock(char *devname)
549e9569
NB
227{
228 char path[100];
229 int sfd;
230 long fl;
231 struct sockaddr_un addr;
232
6144ed44
DW
233 if (sigterm)
234 return -1;
235
549e9569
NB
236 sprintf(path, "/var/run/mdadm/%s.sock", devname);
237 unlink(path);
238 sfd = socket(PF_LOCAL, SOCK_STREAM, 0);
239 if (sfd < 0)
240 return -1;
241
242 addr.sun_family = PF_LOCAL;
243 strcpy(addr.sun_path, path);
244 if (bind(sfd, &addr, sizeof(addr)) < 0) {
245 close(sfd);
246 return -1;
247 }
248 listen(sfd, 10);
249 fl = fcntl(sfd, F_GETFL, 0);
250 fl |= O_NONBLOCK;
251 fcntl(sfd, F_SETFL, fl);
252 return sfd;
253}
254
295646b3
DW
255int socket_hup_requested;
256static void hup(int sig)
257{
258 socket_hup_requested = 1;
259}
260
6144ed44
DW
261static void term(int sig)
262{
263 sigterm = 1;
264}
265
4d43913c
NB
266static void wake_me(int sig)
267{
268
269}
270
16ddab0d
DW
271/* if we are debugging and starting mdmon by hand then don't fork */
272static int do_fork(void)
273{
274 #ifdef DEBUG
40ebbb9c 275 if (check_env("MDADM_NO_MDMON"))
16ddab0d
DW
276 return 0;
277 #endif
278
279 return 1;
280}
281
13047e4c
DW
282void usage(void)
283{
5746141e 284 fprintf(stderr, "Usage: mdmon /device/name/for/container [target_dir]\n");
13047e4c
DW
285 exit(2);
286}
16ddab0d 287
1ffd2840
DW
288int mdmon(char *devname, int devnum, int scan, char *switchroot);
289
549e9569
NB
290int main(int argc, char *argv[])
291{
13047e4c
DW
292 char *container_name = NULL;
293 char *switchroot = NULL;
e8a70c89
N
294 int devnum;
295 char *devname;
1ffd2840
DW
296 int scan = 0;
297 int status = 0;
13047e4c
DW
298
299 switch (argc) {
5746141e
DW
300 case 3:
301 switchroot = argv[2];
13047e4c
DW
302 case 2:
303 container_name = argv[1];
304 break;
13047e4c
DW
305 default:
306 usage();
549e9569 307 }
13047e4c 308
1ffd2840
DW
309 if (strcmp(container_name, "/proc/mdstat") == 0) {
310 struct mdstat_ent *mdstat, *e;
311
312 /* launch an mdmon instance for each container found */
313 scan = 1;
314 mdstat = mdstat_read(0, 0);
315 for (e = mdstat; e; e = e->next) {
316 if (strncmp(e->metadata_version, "external:", 9) == 0 &&
317 !is_subarray(&e->metadata_version[9])) {
318 devname = devnum2devname(e->devnum);
1b34f519
DW
319 /* update cmdline so this mdmon instance can be
320 * distinguished from others in a call to ps(1)
321 */
322 if (strlen(devname) <= strlen(container_name)) {
323 memset(container_name, 0, strlen(container_name));
324 sprintf(container_name, "%s", devname);
325 }
1ffd2840
DW
326 status |= mdmon(devname, e->devnum, scan,
327 switchroot);
328 }
329 }
330 free_mdstat(mdstat);
331
332 return status;
333 } else if (strncmp(container_name, "md", 2) == 0) {
6f4098a6
DW
334 devnum = devname2devnum(container_name);
335 devname = devnum2devname(devnum);
336 if (strcmp(container_name, devname) != 0)
337 devname = NULL;
338 } else {
339 struct stat st;
340
341 devnum = NoMdDev;
342 if (stat(container_name, &st) == 0)
343 devnum = stat2devnum(&st);
344 if (devnum == NoMdDev)
345 devname = NULL;
346 else
347 devname = devnum2devname(devnum);
348 }
349
350 if (!devname) {
e8a70c89
N
351 fprintf(stderr, "mdmon: %s is not a valid md device name\n",
352 container_name);
353 exit(1);
354 }
1ffd2840
DW
355 return mdmon(devname, devnum, scan, switchroot);
356}
357
358int mdmon(char *devname, int devnum, int scan, char *switchroot)
359{
360 int mdfd;
361 struct mdinfo *mdi, *di;
362 struct supertype *container;
363 sigset_t set;
364 struct sigaction act;
365 int pfd[2];
366 int status;
367 int ignore;
96a8270d 368 pid_t victim = -1;
9f1da824 369 int victim_sock = -1;
1ffd2840 370
5746141e
DW
371 dprintf("starting mdmon for %s in %s\n",
372 devname, switchroot ? : "/");
b928b5a0
DW
373
374 /* try to spawn mdmon instances from the target file system */
375 if (switchroot && strcmp(switchroot, "/") != 0) {
376 char path[1024];
377 pid_t pid;
378
379 sprintf(path, "%s/sbin/mdmon", switchroot);
380 switch (fork()) {
381 case 0:
382 execl(path, "mdmon", devname, NULL);
383 exit(1);
384 case -1:
385 return 1;
386 default:
387 pid = wait(&status);
388 if (pid > -1 && WIFEXITED(status) &&
389 WEXITSTATUS(status) == 0)
390 return 0;
391 else
392 return 1;
393 }
394 }
395
e8a70c89 396 mdfd = open_dev(devnum);
549e9569 397 if (mdfd < 0) {
1ffd2840 398 fprintf(stderr, "mdmon: %s: %s\n", devname,
549e9569 399 strerror(errno));
1ffd2840 400 return 1;
549e9569
NB
401 }
402 if (md_get_version(mdfd) < 0) {
13047e4c 403 fprintf(stderr, "mdmon: %s: Not an md device\n",
1ffd2840
DW
404 devname);
405 return 1;
549e9569
NB
406 }
407
9fe32043 408 /* Fork, and have the child tell us when they are ready */
1ffd2840 409 if (do_fork() || scan) {
3d2c4fc7
DW
410 if (pipe(pfd) != 0) {
411 fprintf(stderr, "mdmon: failed to create pipe\n");
1ffd2840 412 return 1;
3d2c4fc7 413 }
16ddab0d
DW
414 switch(fork()) {
415 case -1:
416 fprintf(stderr, "mdmon: failed to fork: %s\n",
417 strerror(errno));
1ffd2840 418 return 1;
16ddab0d
DW
419 case 0: /* child */
420 close(pfd[0]);
421 break;
422 default: /* parent */
423 close(pfd[1]);
424 if (read(pfd[0], &status, sizeof(status)) != sizeof(status)) {
425 wait(&status);
426 status = WEXITSTATUS(status);
427 }
1ffd2840 428 return status;
9fe32043 429 }
16ddab0d
DW
430 } else
431 pfd[0] = pfd[1] = -1;
549e9569 432
f5df5d69 433 container = calloc(1, sizeof(*container));
e8a70c89
N
434 container->devnum = devnum;
435 container->devname = devname;
13047e4c 436 container->arrays = NULL;
c1363b40 437 container->subarray[0] = 0;
96a8270d 438 container->sock = -1;
13047e4c
DW
439
440 if (!container->devname) {
441 fprintf(stderr, "mdmon: failed to allocate container name string\n");
442 exit(3);
443 }
444
445 mdi = sysfs_read(mdfd, container->devnum,
7da80e6f 446 GET_VERSION|GET_LEVEL|GET_DEVS|SKIP_GONE_DEVS);
13047e4c
DW
447
448 if (!mdi) {
449 fprintf(stderr, "mdmon: failed to load sysfs info for %s\n",
450 container->devname);
451 exit(3);
452 }
453 if (mdi->array.level != UnSet) {
454 fprintf(stderr, "mdmon: %s is not a container - cannot monitor\n",
1ffd2840 455 devname);
13047e4c
DW
456 exit(3);
457 }
458 if (mdi->array.major_version != -1 ||
459 mdi->array.minor_version != -2) {
460 fprintf(stderr, "mdmon: %s does not use external metadata - cannot monitor\n",
1ffd2840 461 devname);
13047e4c
DW
462 exit(3);
463 }
464
465 container->ss = find_metadata_methods(mdi->text_version);
466 if (container->ss == NULL) {
467 fprintf(stderr, "mdmon: %s uses unknown metadata: %s\n",
1ffd2840 468 devname, mdi->text_version);
13047e4c
DW
469 exit(3);
470 }
471
472 container->devs = NULL;
473 for (di = mdi->devs; di; di = di->next) {
474 struct mdinfo *cd = malloc(sizeof(*cd));
475 *cd = *di;
476 cd->next = container->devs;
477 container->devs = cd;
478 }
479 sysfs_free(mdi);
549e9569 480
883a6142
DW
481 /* SIGUSR is sent between parent and child. So both block it
482 * and enable it only with pselect.
483 */
484 sigemptyset(&set);
485 sigaddset(&set, SIGUSR1);
486 sigaddset(&set, SIGHUP);
487 sigaddset(&set, SIGALRM);
488 sigaddset(&set, SIGTERM);
489 sigprocmask(SIG_BLOCK, &set, NULL);
490 act.sa_handler = wake_me;
491 act.sa_flags = 0;
492 sigaction(SIGUSR1, &act, NULL);
493 sigaction(SIGALRM, &act, NULL);
494 act.sa_handler = hup;
495 sigaction(SIGHUP, &act, NULL);
496 act.sa_handler = term;
497 sigaction(SIGTERM, &act, NULL);
498 act.sa_handler = SIG_IGN;
499 sigaction(SIGPIPE, &act, NULL);
500
13047e4c
DW
501 if (switchroot) {
502 /* we assume we assume that /sys /proc /dev are available in
96a8270d 503 * the new root
13047e4c 504 */
96a8270d 505 victim = devname2mdmon(container->devname);
9f1da824 506 victim_sock = connect_monitor(container->devname);
13047e4c
DW
507 if (chroot(switchroot) != 0) {
508 fprintf(stderr, "mdmon: failed to chroot to '%s': %s\n",
509 switchroot, strerror(errno));
510 exit(4);
511 }
512 }
513
13047e4c 514 ignore = chdir("/");
96a8270d 515 if (victim < 0 && test_pidfile(container->devname) == 0) {
b109d928
DW
516 if (ping_monitor(container->devname) == 0) {
517 fprintf(stderr, "mdmon: %s already managed\n",
518 container->devname);
519 exit(3);
96a8270d
DW
520 } else if (victim < 0)
521 victim = devname2mdmon(container->devname);
549e9569 522 }
1ffd2840 523 if (container->ss->load_super(container, mdfd, devname)) {
549e9569 524 fprintf(stderr, "mdmon: Cannot load metadata for %s\n",
1ffd2840 525 devname);
549e9569
NB
526 exit(3);
527 }
e8a70c89 528 close(mdfd);
549e9569 529
9fe32043
N
530 /* Ok, this is close enough. We can say goodbye to our parent now.
531 */
532 status = 0;
3d2c4fc7
DW
533 if (write(pfd[1], &status, sizeof(status)) < 0)
534 fprintf(stderr, "mdmon: failed to notify our parent: %d\n",
535 getppid());
9fe32043
N
536 close(pfd[1]);
537
9fe32043
N
538 setsid();
539 close(0);
540 open("/dev/null", O_RDWR);
541 close(1);
3d2c4fc7 542 ignore = dup(0);
9fe32043
N
543#ifndef DEBUG
544 close(2);
3d2c4fc7 545 ignore = dup(0);
9fe32043
N
546#endif
547
1373b07d 548 mlockall(MCL_CURRENT | MCL_FUTURE);
549e9569 549
3e70c845 550 if (clone_monitor(container) < 0) {
295646b3 551 fprintf(stderr, "mdmon: failed to start monitor process: %s\n",
549e9569
NB
552 strerror(errno));
553 exit(2);
554 }
555
9f1da824
DW
556 if (victim > -1) {
557 try_kill_monitor(victim, container->devname, victim_sock);
558 close(victim_sock);
559 }
549e9569
NB
560 do_manager(container);
561
562 exit(0);
563}