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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 | ||
b109d928 | 83 | static 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 NB |
91 | if (fd < 0) |
92 | return -1; | |
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); | |
139 | } | |
140 | ||
549e9569 NB |
141 | static int make_control_sock(char *devname) |
142 | { | |
143 | char path[100]; | |
144 | int sfd; | |
145 | long fl; | |
146 | struct sockaddr_un addr; | |
147 | ||
148 | sprintf(path, "/var/run/mdadm/%s.sock", devname); | |
149 | unlink(path); | |
150 | sfd = socket(PF_LOCAL, SOCK_STREAM, 0); | |
151 | if (sfd < 0) | |
152 | return -1; | |
153 | ||
154 | addr.sun_family = PF_LOCAL; | |
155 | strcpy(addr.sun_path, path); | |
156 | if (bind(sfd, &addr, sizeof(addr)) < 0) { | |
157 | close(sfd); | |
158 | return -1; | |
159 | } | |
160 | listen(sfd, 10); | |
161 | fl = fcntl(sfd, F_GETFL, 0); | |
162 | fl |= O_NONBLOCK; | |
163 | fcntl(sfd, F_SETFL, fl); | |
164 | return sfd; | |
165 | } | |
166 | ||
4d43913c NB |
167 | static void wake_me(int sig) |
168 | { | |
169 | ||
170 | } | |
171 | ||
16ddab0d DW |
172 | /* if we are debugging and starting mdmon by hand then don't fork */ |
173 | static int do_fork(void) | |
174 | { | |
175 | #ifdef DEBUG | |
176 | if (env_no_mdmon()) | |
177 | return 0; | |
178 | #endif | |
179 | ||
180 | return 1; | |
181 | } | |
182 | ||
183 | ||
184 | ||
549e9569 NB |
185 | int main(int argc, char *argv[]) |
186 | { | |
187 | int mdfd; | |
549e9569 NB |
188 | struct mdinfo *mdi, *di; |
189 | struct supertype *container; | |
4d43913c | 190 | sigset_t set; |
bfa44e2e | 191 | struct sigaction act; |
9fe32043 N |
192 | int pfd[2]; |
193 | int status; | |
4d43913c | 194 | |
549e9569 NB |
195 | if (argc != 2) { |
196 | fprintf(stderr, "Usage: md-manage /device/name/for/container\n"); | |
197 | exit(2); | |
198 | } | |
199 | mdfd = open(argv[1], O_RDWR); | |
200 | if (mdfd < 0) { | |
201 | fprintf(stderr, "md-manage: %s: %s\n", argv[1], | |
202 | strerror(errno)); | |
203 | exit(1); | |
204 | } | |
205 | if (md_get_version(mdfd) < 0) { | |
206 | fprintf(stderr, "md-manage: %s: Not an md device\n", | |
207 | argv[1]); | |
208 | exit(1); | |
209 | } | |
210 | ||
9fe32043 | 211 | /* Fork, and have the child tell us when they are ready */ |
16ddab0d DW |
212 | if (do_fork()) { |
213 | pipe(pfd); | |
214 | switch(fork()) { | |
215 | case -1: | |
216 | fprintf(stderr, "mdmon: failed to fork: %s\n", | |
217 | strerror(errno)); | |
218 | exit(1); | |
219 | case 0: /* child */ | |
220 | close(pfd[0]); | |
221 | break; | |
222 | default: /* parent */ | |
223 | close(pfd[1]); | |
224 | if (read(pfd[0], &status, sizeof(status)) != sizeof(status)) { | |
225 | wait(&status); | |
226 | status = WEXITSTATUS(status); | |
227 | } | |
228 | exit(status); | |
9fe32043 | 229 | } |
16ddab0d DW |
230 | } else |
231 | pfd[0] = pfd[1] = -1; | |
549e9569 NB |
232 | /* hopefully it is a container - we'll check later */ |
233 | ||
234 | container = malloc(sizeof(*container)); | |
549e9569 NB |
235 | container->devnum = fd2devnum(mdfd); |
236 | container->devname = devnum2devname(container->devnum); | |
e0d6609f | 237 | container->device_name = argv[1]; |
549e9569 NB |
238 | |
239 | /* If this fails, we hope it already exists */ | |
240 | mkdir("/var/run/mdadm", 0600); | |
241 | /* pid file lives in /var/run/mdadm/mdXX.pid */ | |
b109d928 DW |
242 | if (make_pidfile(container->devname, O_EXCL) < 0) { |
243 | if (ping_monitor(container->devname) == 0) { | |
244 | fprintf(stderr, "mdmon: %s already managed\n", | |
245 | container->devname); | |
246 | exit(3); | |
247 | } else { | |
248 | /* cleanup the old monitor, this one is taking over */ | |
249 | try_kill_monitor(container->devname); | |
250 | if (make_pidfile(container->devname, 0) < 0) { | |
251 | fprintf(stderr, "mdmon: %s Cannot create pidfile\n", | |
252 | container->devname); | |
253 | exit(3); | |
254 | } | |
255 | } | |
549e9569 NB |
256 | } |
257 | ||
258 | container->sock = make_control_sock(container->devname); | |
259 | if (container->sock < 0) { | |
260 | fprintf(stderr, "mdmon: Cannot create socket in /var/run/mdadm\n"); | |
261 | exit(3); | |
262 | } | |
263 | container->arrays = NULL; | |
264 | ||
265 | mdi = sysfs_read(mdfd, container->devnum, | |
266 | GET_VERSION|GET_LEVEL|GET_DEVS); | |
267 | ||
268 | if (!mdi) { | |
269 | fprintf(stderr, "mdmon: failed to load sysfs info for %s\n", | |
270 | container->devname); | |
271 | exit(3); | |
272 | } | |
273 | if (mdi->array.level != UnSet) { | |
274 | fprintf(stderr, "mdmon: %s is not a container - cannot monitor\n", | |
275 | argv[1]); | |
276 | exit(3); | |
277 | } | |
278 | if (mdi->array.major_version != -1 || | |
279 | mdi->array.minor_version != -2) { | |
280 | fprintf(stderr, "mdmon: %s does not use external metadata - cannot monitor\n", | |
281 | argv[1]); | |
282 | exit(3); | |
283 | } | |
284 | ||
285 | container->ss = find_metadata_methods(mdi->text_version); | |
286 | if (container->ss == NULL) { | |
287 | fprintf(stderr, "mdmon: %s uses unknown metadata: %s\n", | |
288 | argv[1], mdi->text_version); | |
289 | exit(3); | |
290 | } | |
291 | ||
292 | container->devs = NULL; | |
293 | for (di = mdi->devs; di; di = di->next) { | |
294 | struct mdinfo *cd = malloc(sizeof(*cd)); | |
295 | cd = di; | |
296 | cd->next = container->devs; | |
297 | container->devs = cd; | |
298 | } | |
299 | sysfs_free(mdi); | |
300 | ||
301 | ||
302 | if (container->ss->load_super(container, mdfd, argv[1])) { | |
303 | fprintf(stderr, "mdmon: Cannot load metadata for %s\n", | |
304 | argv[1]); | |
305 | exit(3); | |
306 | } | |
549e9569 | 307 | |
9fe32043 N |
308 | /* Ok, this is close enough. We can say goodbye to our parent now. |
309 | */ | |
310 | status = 0; | |
311 | write(pfd[1], &status, sizeof(status)); | |
312 | close(pfd[1]); | |
313 | ||
314 | chdir("/"); | |
315 | setsid(); | |
316 | close(0); | |
317 | open("/dev/null", O_RDWR); | |
318 | close(1); | |
319 | dup(0); | |
320 | #ifndef DEBUG | |
321 | close(2); | |
322 | dup(0); | |
323 | #endif | |
324 | ||
549e9569 NB |
325 | mlockall(MCL_FUTURE); |
326 | ||
4d43913c NB |
327 | /* SIGUSR is sent between parent and child. So both block it |
328 | * and enable it only with pselect. | |
329 | */ | |
330 | sigemptyset(&set); | |
331 | sigaddset(&set, SIGUSR1); | |
332 | sigprocmask(SIG_BLOCK, &set, NULL); | |
bfa44e2e NB |
333 | act.sa_handler = wake_me; |
334 | act.sa_flags = 0; | |
335 | sigaction(SIGUSR1, &act, NULL); | |
336 | act.sa_handler = SIG_IGN; | |
337 | sigaction(SIGPIPE, &act, NULL); | |
4d43913c | 338 | |
3e70c845 | 339 | if (clone_monitor(container) < 0) { |
549e9569 NB |
340 | fprintf(stderr, "md-manage: failed to start monitor process: %s\n", |
341 | strerror(errno)); | |
342 | exit(2); | |
343 | } | |
344 | ||
345 | do_manager(container); | |
346 | ||
347 | exit(0); | |
348 | } |