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1 | /* | |
2 | * mdmon - monitor external metadata arrays | |
3 | * | |
4 | * Copyright (C) 2007-2009 Neil Brown <neilb@suse.de> | |
5 | * Copyright (C) 2007-2009 Intel Corporation | |
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 | */ | |
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> | |
48 | #include <sys/types.h> | |
49 | #include <sys/stat.h> | |
50 | #include <sys/socket.h> | |
51 | #include <sys/un.h> | |
52 | #include <sys/mman.h> | |
53 | #include <sys/syscall.h> | |
54 | #include <sys/wait.h> | |
55 | #include <stdio.h> | |
56 | #include <errno.h> | |
57 | #include <string.h> | |
58 | #include <fcntl.h> | |
59 | #include <signal.h> | |
60 | #include <dirent.h> | |
61 | #ifdef USE_PTHREADS | |
62 | #include <pthread.h> | |
63 | #else | |
64 | #include <sched.h> | |
65 | #endif | |
66 | ||
67 | #include "mdadm.h" | |
68 | #include "mdmon.h" | |
69 | ||
70 | struct active_array *discard_this; | |
71 | struct active_array *pending_discard; | |
72 | ||
73 | int mon_tid, mgr_tid; | |
74 | ||
75 | int sigterm; | |
76 | ||
77 | #ifdef USE_PTHREADS | |
78 | static void *run_child(void *v) | |
79 | { | |
80 | struct supertype *c = v; | |
81 | ||
82 | mon_tid = syscall(SYS_gettid); | |
83 | do_monitor(c); | |
84 | return 0; | |
85 | } | |
86 | ||
87 | static int clone_monitor(struct supertype *container) | |
88 | { | |
89 | pthread_attr_t attr; | |
90 | pthread_t thread; | |
91 | int rc; | |
92 | ||
93 | mon_tid = -1; | |
94 | pthread_attr_init(&attr); | |
95 | pthread_attr_setstacksize(&attr, 4096); | |
96 | pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED); | |
97 | rc = pthread_create(&thread, &attr, run_child, container); | |
98 | if (rc) | |
99 | return rc; | |
100 | while (mon_tid == -1) | |
101 | usleep(10); | |
102 | pthread_attr_destroy(&attr); | |
103 | ||
104 | mgr_tid = syscall(SYS_gettid); | |
105 | ||
106 | return mon_tid; | |
107 | } | |
108 | #else /* USE_PTHREADS */ | |
109 | static int run_child(void *v) | |
110 | { | |
111 | struct supertype *c = v; | |
112 | ||
113 | do_monitor(c); | |
114 | return 0; | |
115 | } | |
116 | ||
117 | #ifdef __ia64__ | |
118 | int __clone2(int (*fn)(void *), | |
119 | void *child_stack_base, size_t stack_size, | |
120 | int flags, void *arg, ... | |
121 | /* pid_t *pid, struct user_desc *tls, pid_t *ctid */ ); | |
122 | #endif | |
123 | static int clone_monitor(struct supertype *container) | |
124 | { | |
125 | static char stack[4096]; | |
126 | ||
127 | #ifdef __ia64__ | |
128 | mon_tid = __clone2(run_child, stack, sizeof(stack), | |
129 | CLONE_FS|CLONE_FILES|CLONE_VM|CLONE_SIGHAND|CLONE_THREAD, | |
130 | container); | |
131 | #else | |
132 | mon_tid = clone(run_child, stack+4096-64, | |
133 | CLONE_FS|CLONE_FILES|CLONE_VM|CLONE_SIGHAND|CLONE_THREAD, | |
134 | container); | |
135 | #endif | |
136 | ||
137 | mgr_tid = syscall(SYS_gettid); | |
138 | ||
139 | return mon_tid; | |
140 | } | |
141 | #endif /* USE_PTHREADS */ | |
142 | ||
143 | static int make_pidfile(char *devname) | |
144 | { | |
145 | char path[100]; | |
146 | char pid[10]; | |
147 | int fd; | |
148 | int n; | |
149 | ||
150 | if (mkdir(MDMON_DIR, 0755) < 0 && | |
151 | errno != EEXIST) | |
152 | return -errno; | |
153 | sprintf(path, "%s/%s.pid", MDMON_DIR, devname); | |
154 | ||
155 | fd = open(path, O_RDWR|O_CREAT|O_EXCL, 0600); | |
156 | if (fd < 0) | |
157 | return -errno; | |
158 | sprintf(pid, "%d\n", getpid()); | |
159 | n = write(fd, pid, strlen(pid)); | |
160 | close(fd); | |
161 | if (n < 0) | |
162 | return -errno; | |
163 | return 0; | |
164 | } | |
165 | ||
166 | static void try_kill_monitor(pid_t pid, char *devname, int sock) | |
167 | { | |
168 | char buf[100]; | |
169 | int fd; | |
170 | int n; | |
171 | long fl; | |
172 | ||
173 | /* first rule of survival... don't off yourself */ | |
174 | if (pid == getpid()) | |
175 | return; | |
176 | ||
177 | /* kill this process if it is mdmon */ | |
178 | sprintf(buf, "/proc/%lu/cmdline", (unsigned long) pid); | |
179 | fd = open(buf, O_RDONLY); | |
180 | if (fd < 0) | |
181 | return; | |
182 | ||
183 | n = read(fd, buf, sizeof(buf)-1); | |
184 | buf[sizeof(buf)-1] = 0; | |
185 | close(fd); | |
186 | ||
187 | if (n < 0 || !(strstr(buf, "mdmon") || | |
188 | strstr(buf, "@dmon"))) | |
189 | return; | |
190 | ||
191 | kill(pid, SIGTERM); | |
192 | ||
193 | if (sock < 0) | |
194 | return; | |
195 | ||
196 | /* Wait for monitor to exit by reading from the socket, after | |
197 | * clearing the non-blocking flag */ | |
198 | fl = fcntl(sock, F_GETFL, 0); | |
199 | fl &= ~O_NONBLOCK; | |
200 | fcntl(sock, F_SETFL, fl); | |
201 | n = read(sock, buf, 100); | |
202 | /* Ignore result, it is just the wait that | |
203 | * matters | |
204 | */ | |
205 | } | |
206 | ||
207 | void remove_pidfile(char *devname) | |
208 | { | |
209 | char buf[100]; | |
210 | ||
211 | sprintf(buf, "%s/%s.pid", MDMON_DIR, devname); | |
212 | unlink(buf); | |
213 | sprintf(buf, "%s/%s.sock", MDMON_DIR, devname); | |
214 | unlink(buf); | |
215 | } | |
216 | ||
217 | static int make_control_sock(char *devname) | |
218 | { | |
219 | char path[100]; | |
220 | int sfd; | |
221 | long fl; | |
222 | struct sockaddr_un addr; | |
223 | ||
224 | if (sigterm) | |
225 | return -1; | |
226 | ||
227 | sprintf(path, "%s/%s.sock", MDMON_DIR, devname); | |
228 | unlink(path); | |
229 | sfd = socket(PF_LOCAL, SOCK_STREAM, 0); | |
230 | if (sfd < 0) | |
231 | return -1; | |
232 | ||
233 | addr.sun_family = PF_LOCAL; | |
234 | strcpy(addr.sun_path, path); | |
235 | if (bind(sfd, &addr, sizeof(addr)) < 0) { | |
236 | close(sfd); | |
237 | return -1; | |
238 | } | |
239 | listen(sfd, 10); | |
240 | fl = fcntl(sfd, F_GETFL, 0); | |
241 | fl |= O_NONBLOCK; | |
242 | fcntl(sfd, F_SETFL, fl); | |
243 | return sfd; | |
244 | } | |
245 | ||
246 | static void term(int sig) | |
247 | { | |
248 | sigterm = 1; | |
249 | } | |
250 | ||
251 | static void wake_me(int sig) | |
252 | { | |
253 | ||
254 | } | |
255 | ||
256 | /* if we are debugging and starting mdmon by hand then don't fork */ | |
257 | static int do_fork(void) | |
258 | { | |
259 | #ifdef DEBUG | |
260 | if (check_env("MDADM_NO_MDMON")) | |
261 | return 0; | |
262 | #endif | |
263 | ||
264 | return 1; | |
265 | } | |
266 | ||
267 | void usage(void) | |
268 | { | |
269 | fprintf(stderr, | |
270 | "Usage: mdmon [options] CONTAINER\n" | |
271 | "\n" | |
272 | "Options are:\n" | |
273 | " --help -h : This message\n" | |
274 | " --all : All devices\n" | |
275 | " --takeover -t : Takeover container\n" | |
276 | ); | |
277 | exit(2); | |
278 | } | |
279 | ||
280 | static int mdmon(char *devname, int devnum, int must_fork, int takeover); | |
281 | ||
282 | int main(int argc, char *argv[]) | |
283 | { | |
284 | char *container_name = NULL; | |
285 | int devnum; | |
286 | char *devname; | |
287 | int status = 0; | |
288 | int opt; | |
289 | int all = 0; | |
290 | int takeover = 0; | |
291 | int dofork = 1; | |
292 | static struct option options[] = { | |
293 | {"all", 0, NULL, 'a'}, | |
294 | {"takeover", 0, NULL, 't'}, | |
295 | {"help", 0, NULL, 'h'}, | |
296 | {"offroot", 0, NULL, OffRootOpt}, | |
297 | {"foreground", 0, NULL, 'F'}, | |
298 | {NULL, 0, NULL, 0} | |
299 | }; | |
300 | ||
301 | /* | |
302 | * Always change process name to @dmon to avoid systemd killing it | |
303 | */ | |
304 | argv[0][0] = '@'; | |
305 | ||
306 | while ((opt = getopt_long(argc, argv, "thaF", options, NULL)) != -1) { | |
307 | switch (opt) { | |
308 | case 'a': | |
309 | container_name = argv[optind-1]; | |
310 | all = 1; | |
311 | break; | |
312 | case 't': | |
313 | takeover = 1; | |
314 | break; | |
315 | case 'F': | |
316 | dofork = 0; | |
317 | break; | |
318 | case OffRootOpt: | |
319 | /* silently ignore old option */ | |
320 | break; | |
321 | case 'h': | |
322 | default: | |
323 | usage(); | |
324 | break; | |
325 | } | |
326 | } | |
327 | ||
328 | if (all == 0 && container_name == NULL) { | |
329 | if (argv[optind]) | |
330 | container_name = argv[optind]; | |
331 | } | |
332 | ||
333 | if (container_name == NULL) | |
334 | usage(); | |
335 | ||
336 | if (argc - optind > 1) | |
337 | usage(); | |
338 | ||
339 | if (strcmp(container_name, "/proc/mdstat") == 0) | |
340 | all = 1; | |
341 | ||
342 | if (all) { | |
343 | struct mdstat_ent *mdstat, *e; | |
344 | int container_len = strlen(container_name); | |
345 | ||
346 | /* launch an mdmon instance for each container found */ | |
347 | mdstat = mdstat_read(0, 0); | |
348 | for (e = mdstat; e; e = e->next) { | |
349 | if (e->metadata_version && | |
350 | strncmp(e->metadata_version, "external:", 9) == 0 && | |
351 | !is_subarray(&e->metadata_version[9])) { | |
352 | devname = devnum2devname(e->devnum); | |
353 | /* update cmdline so this mdmon instance can be | |
354 | * distinguished from others in a call to ps(1) | |
355 | */ | |
356 | if (strlen(devname) <= (unsigned)container_len) { | |
357 | memset(container_name, 0, container_len); | |
358 | sprintf(container_name, "%s", devname); | |
359 | } | |
360 | status |= mdmon(devname, e->devnum, 1, | |
361 | takeover); | |
362 | } | |
363 | } | |
364 | free_mdstat(mdstat); | |
365 | ||
366 | return status; | |
367 | } else if (strncmp(container_name, "md", 2) == 0) { | |
368 | devnum = devname2devnum(container_name); | |
369 | devname = devnum2devname(devnum); | |
370 | if (strcmp(container_name, devname) != 0) | |
371 | devname = NULL; | |
372 | } else { | |
373 | struct stat st; | |
374 | ||
375 | devnum = NoMdDev; | |
376 | if (stat(container_name, &st) == 0) | |
377 | devnum = stat2devnum(&st); | |
378 | if (devnum == NoMdDev) | |
379 | devname = NULL; | |
380 | else | |
381 | devname = devnum2devname(devnum); | |
382 | } | |
383 | ||
384 | if (!devname) { | |
385 | fprintf(stderr, "mdmon: %s is not a valid md device name\n", | |
386 | container_name); | |
387 | exit(1); | |
388 | } | |
389 | return mdmon(devname, devnum, dofork && do_fork(), takeover); | |
390 | } | |
391 | ||
392 | static int mdmon(char *devname, int devnum, int must_fork, int takeover) | |
393 | { | |
394 | int mdfd; | |
395 | struct mdinfo *mdi, *di; | |
396 | struct supertype *container; | |
397 | sigset_t set; | |
398 | struct sigaction act; | |
399 | int pfd[2]; | |
400 | int status; | |
401 | int ignore; | |
402 | pid_t victim = -1; | |
403 | int victim_sock = -1; | |
404 | ||
405 | dprintf("starting mdmon for %s\n", devname); | |
406 | ||
407 | mdfd = open_dev(devnum); | |
408 | if (mdfd < 0) { | |
409 | fprintf(stderr, "mdmon: %s: %s\n", devname, | |
410 | strerror(errno)); | |
411 | return 1; | |
412 | } | |
413 | if (md_get_version(mdfd) < 0) { | |
414 | fprintf(stderr, "mdmon: %s: Not an md device\n", | |
415 | devname); | |
416 | return 1; | |
417 | } | |
418 | ||
419 | /* Fork, and have the child tell us when they are ready */ | |
420 | if (must_fork) { | |
421 | if (pipe(pfd) != 0) { | |
422 | fprintf(stderr, "mdmon: failed to create pipe\n"); | |
423 | return 1; | |
424 | } | |
425 | switch(fork()) { | |
426 | case -1: | |
427 | fprintf(stderr, "mdmon: failed to fork: %s\n", | |
428 | strerror(errno)); | |
429 | return 1; | |
430 | case 0: /* child */ | |
431 | close(pfd[0]); | |
432 | break; | |
433 | default: /* parent */ | |
434 | close(pfd[1]); | |
435 | if (read(pfd[0], &status, sizeof(status)) != sizeof(status)) { | |
436 | wait(&status); | |
437 | status = WEXITSTATUS(status); | |
438 | } | |
439 | return status; | |
440 | } | |
441 | } else | |
442 | pfd[0] = pfd[1] = -1; | |
443 | ||
444 | container = xcalloc(1, sizeof(*container)); | |
445 | container->devnum = devnum; | |
446 | container->devname = devname; | |
447 | container->arrays = NULL; | |
448 | container->sock = -1; | |
449 | ||
450 | if (!container->devname) { | |
451 | fprintf(stderr, "mdmon: failed to allocate container name string\n"); | |
452 | exit(3); | |
453 | } | |
454 | ||
455 | mdi = sysfs_read(mdfd, container->devnum, GET_VERSION|GET_LEVEL|GET_DEVS); | |
456 | ||
457 | if (!mdi) { | |
458 | fprintf(stderr, "mdmon: failed to load sysfs info for %s\n", | |
459 | container->devname); | |
460 | exit(3); | |
461 | } | |
462 | if (mdi->array.level != UnSet) { | |
463 | fprintf(stderr, "mdmon: %s is not a container - cannot monitor\n", | |
464 | devname); | |
465 | exit(3); | |
466 | } | |
467 | if (mdi->array.major_version != -1 || | |
468 | mdi->array.minor_version != -2) { | |
469 | fprintf(stderr, "mdmon: %s does not use external metadata - cannot monitor\n", | |
470 | devname); | |
471 | exit(3); | |
472 | } | |
473 | ||
474 | container->ss = version_to_superswitch(mdi->text_version); | |
475 | if (container->ss == NULL) { | |
476 | fprintf(stderr, "mdmon: %s uses unsupported metadata: %s\n", | |
477 | devname, mdi->text_version); | |
478 | exit(3); | |
479 | } | |
480 | ||
481 | container->devs = NULL; | |
482 | for (di = mdi->devs; di; di = di->next) { | |
483 | struct mdinfo *cd = xmalloc(sizeof(*cd)); | |
484 | *cd = *di; | |
485 | cd->next = container->devs; | |
486 | container->devs = cd; | |
487 | } | |
488 | sysfs_free(mdi); | |
489 | ||
490 | /* SIGUSR is sent between parent and child. So both block it | |
491 | * and enable it only with pselect. | |
492 | */ | |
493 | sigemptyset(&set); | |
494 | sigaddset(&set, SIGUSR1); | |
495 | sigaddset(&set, SIGTERM); | |
496 | sigprocmask(SIG_BLOCK, &set, NULL); | |
497 | act.sa_handler = wake_me; | |
498 | act.sa_flags = 0; | |
499 | sigaction(SIGUSR1, &act, NULL); | |
500 | act.sa_handler = term; | |
501 | sigaction(SIGTERM, &act, NULL); | |
502 | act.sa_handler = SIG_IGN; | |
503 | sigaction(SIGPIPE, &act, NULL); | |
504 | ||
505 | victim = mdmon_pid(container->devnum); | |
506 | if (victim >= 0) | |
507 | victim_sock = connect_monitor(container->devname); | |
508 | ||
509 | ignore = chdir("/"); | |
510 | if (!takeover && victim > 0 && victim_sock >= 0) { | |
511 | if (fping_monitor(victim_sock) == 0) { | |
512 | fprintf(stderr, "mdmon: %s already managed\n", | |
513 | container->devname); | |
514 | exit(3); | |
515 | } | |
516 | close(victim_sock); | |
517 | victim_sock = -1; | |
518 | } | |
519 | if (container->ss->load_container(container, mdfd, devname)) { | |
520 | fprintf(stderr, "mdmon: Cannot load metadata for %s\n", | |
521 | devname); | |
522 | exit(3); | |
523 | } | |
524 | close(mdfd); | |
525 | ||
526 | /* Ok, this is close enough. We can say goodbye to our parent now. | |
527 | */ | |
528 | if (victim > 0) | |
529 | remove_pidfile(devname); | |
530 | if (make_pidfile(devname) < 0) { | |
531 | exit(3); | |
532 | } | |
533 | container->sock = make_control_sock(devname); | |
534 | ||
535 | status = 0; | |
536 | if (write(pfd[1], &status, sizeof(status)) < 0) | |
537 | fprintf(stderr, "mdmon: failed to notify our parent: %d\n", | |
538 | getppid()); | |
539 | close(pfd[1]); | |
540 | ||
541 | mlockall(MCL_CURRENT | MCL_FUTURE); | |
542 | ||
543 | if (clone_monitor(container) < 0) { | |
544 | fprintf(stderr, "mdmon: failed to start monitor process: %s\n", | |
545 | strerror(errno)); | |
546 | exit(2); | |
547 | } | |
548 | ||
549 | if (victim > 0) { | |
550 | try_kill_monitor(victim, container->devname, victim_sock); | |
551 | if (victim_sock >= 0) | |
552 | close(victim_sock); | |
553 | } | |
554 | ||
555 | setsid(); | |
556 | close(0); | |
557 | open("/dev/null", O_RDWR); | |
558 | close(1); | |
559 | ignore = dup(0); | |
560 | #ifndef DEBUG | |
561 | close(2); | |
562 | ignore = dup(0); | |
563 | #endif | |
564 | ||
565 | /* This silliness is to stop the compiler complaining | |
566 | * that we ignore 'ignore' | |
567 | */ | |
568 | if (ignore) | |
569 | ignore++; | |
570 | ||
571 | do_manager(container); | |
572 | ||
573 | exit(0); | |
574 | } | |
575 | ||
576 | /* Some stub functions so super-* can link with us */ | |
577 | int child_monitor(int afd, struct mdinfo *sra, struct reshape *reshape, | |
578 | struct supertype *st, unsigned long blocks, | |
579 | int *fds, unsigned long long *offsets, | |
580 | int dests, int *destfd, unsigned long long *destoffsets) | |
581 | { | |
582 | return 0; | |
583 | } | |
584 | ||
585 | int restore_stripes(int *dest, unsigned long long *offsets, | |
586 | int raid_disks, int chunk_size, int level, int layout, | |
587 | int source, unsigned long long read_offset, | |
588 | unsigned long long start, unsigned long long length, | |
589 | char *src_buf) | |
590 | { | |
591 | return 1; | |
592 | } | |
593 | ||
594 | void abort_reshape(struct mdinfo *sra) | |
595 | { | |
596 | return; | |
597 | } | |
598 | ||
599 | int save_stripes(int *source, unsigned long long *offsets, | |
600 | int raid_disks, int chunk_size, int level, int layout, | |
601 | int nwrites, int *dest, | |
602 | unsigned long long start, unsigned long long length, | |
603 | char *buf) | |
604 | { | |
605 | return 0; | |
606 | } |