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git.ipfire.org Git - thirdparty/mdadm.git/blob - mdmon.c
4 * When md arrays have user-space managed metadata, this is the program
5 * that does the managing.
7 * Given one argument: the name of the array (e.g. /dev/md0) that is
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.
15 * The main thread communicates with the priority thread by writing over
17 * Separate programs can communicate with the main thread via Unix-domain
19 * The two threads share address space and open file table.
29 #include <sys/types.h>
31 #include <sys/socket.h>
34 #include <sys/syscall.h>
47 struct active_array
*discard_this
;
48 struct active_array
*pending_discard
;
52 int run_child(void *v
)
54 struct supertype
*c
= v
;
60 int clone_monitor(struct supertype
*container
)
62 static char stack
[4096];
64 mon_tid
= clone(run_child
, stack
+4096-64,
65 CLONE_FS
|CLONE_FILES
|CLONE_VM
|CLONE_SIGHAND
|CLONE_THREAD
,
68 mgr_tid
= syscall(SYS_gettid
);
73 static struct superswitch
*find_metadata_methods(char *vers
)
75 if (strcmp(vers
, "ddf") == 0)
77 if (strcmp(vers
, "imsm") == 0)
83 int make_pidfile(char *devname
, int o_excl
)
90 sprintf(path
, "/var/run/mdadm/%s.pid", devname
);
92 fd
= open(path
, O_RDWR
|O_CREAT
|o_excl
, 0600);
95 sprintf(pid
, "%d\n", getpid());
96 n
= write(fd
, pid
, strlen(pid
));
103 static void try_kill_monitor(char *devname
)
109 sprintf(buf
, "/var/run/mdadm/%s.pid", devname
);
110 fd
= open(buf
, O_RDONLY
);
114 if (read(fd
, buf
, sizeof(buf
)) < 0) {
120 pid
= strtoul(buf
, NULL
, 10);
122 /* kill this process if it is mdmon */
123 sprintf(buf
, "/proc/%lu/cmdline", (unsigned long) pid
);
124 fd
= open(buf
, O_RDONLY
);
128 if (read(fd
, buf
, sizeof(buf
)) < 0) {
133 if (strstr(buf
, "mdmon") != NULL
)
137 void remove_pidfile(char *devname
)
141 sprintf(buf
, "/var/run/mdadm/%s.pid", devname
);
143 sprintf(buf
, "/var/run/mdadm/%s.sock", devname
);
147 int make_control_sock(char *devname
)
152 struct sockaddr_un addr
;
154 sprintf(path
, "/var/run/mdadm/%s.sock", devname
);
156 sfd
= socket(PF_LOCAL
, SOCK_STREAM
, 0);
160 addr
.sun_family
= PF_LOCAL
;
161 strcpy(addr
.sun_path
, path
);
162 if (bind(sfd
, &addr
, sizeof(addr
)) < 0) {
167 fl
= fcntl(sfd
, F_GETFL
, 0);
169 fcntl(sfd
, F_SETFL
, fl
);
173 int socket_hup_requested
;
174 static void hup(int sig
)
176 socket_hup_requested
= 1;
179 static void wake_me(int sig
)
184 /* if we are debugging and starting mdmon by hand then don't fork */
185 static int do_fork(void)
197 int main(int argc
, char *argv
[])
200 struct mdinfo
*mdi
, *di
;
201 struct supertype
*container
;
203 struct sigaction act
;
209 fprintf(stderr
, "Usage: md-manage /device/name/for/container\n");
212 mdfd
= open(argv
[1], O_RDWR
);
214 fprintf(stderr
, "md-manage: %s: %s\n", argv
[1],
218 if (md_get_version(mdfd
) < 0) {
219 fprintf(stderr
, "md-manage: %s: Not an md device\n",
224 /* Fork, and have the child tell us when they are ready */
226 if (pipe(pfd
) != 0) {
227 fprintf(stderr
, "mdmon: failed to create pipe\n");
232 fprintf(stderr
, "mdmon: failed to fork: %s\n",
238 default: /* parent */
240 if (read(pfd
[0], &status
, sizeof(status
)) != sizeof(status
)) {
242 status
= WEXITSTATUS(status
);
247 pfd
[0] = pfd
[1] = -1;
248 /* hopefully it is a container - we'll check later */
250 container
= malloc(sizeof(*container
));
251 container
->devnum
= fd2devnum(mdfd
);
252 container
->devname
= devnum2devname(container
->devnum
);
253 container
->device_name
= argv
[1];
255 /* If this fails, we hope it already exists */
256 mkdir("/var/run/mdadm", 0600);
257 /* pid file lives in /var/run/mdadm/mdXX.pid */
258 if (make_pidfile(container
->devname
, O_EXCL
) < 0) {
259 if (ping_monitor(container
->devname
) == 0) {
260 fprintf(stderr
, "mdmon: %s already managed\n",
266 /* cleanup the old monitor, this one is taking over */
267 try_kill_monitor(container
->devname
);
268 err
= make_pidfile(container
->devname
, 0);
270 fprintf(stderr
, "mdmon: %s Cannot create pidfile\n",
273 /* FIXME implement a mechanism to
274 * prevent duplicate monitor instances
277 "mdmon: continuing on read-only file system\n");
284 container
->sock
= make_control_sock(container
->devname
);
285 container
->arrays
= NULL
;
287 mdi
= sysfs_read(mdfd
, container
->devnum
,
288 GET_VERSION
|GET_LEVEL
|GET_DEVS
);
291 fprintf(stderr
, "mdmon: failed to load sysfs info for %s\n",
295 if (mdi
->array
.level
!= UnSet
) {
296 fprintf(stderr
, "mdmon: %s is not a container - cannot monitor\n",
300 if (mdi
->array
.major_version
!= -1 ||
301 mdi
->array
.minor_version
!= -2) {
302 fprintf(stderr
, "mdmon: %s does not use external metadata - cannot monitor\n",
307 container
->ss
= find_metadata_methods(mdi
->text_version
);
308 if (container
->ss
== NULL
) {
309 fprintf(stderr
, "mdmon: %s uses unknown metadata: %s\n",
310 argv
[1], mdi
->text_version
);
314 container
->devs
= NULL
;
315 for (di
= mdi
->devs
; di
; di
= di
->next
) {
316 struct mdinfo
*cd
= malloc(sizeof(*cd
));
318 cd
->next
= container
->devs
;
319 container
->devs
= cd
;
324 if (container
->ss
->load_super(container
, mdfd
, argv
[1])) {
325 fprintf(stderr
, "mdmon: Cannot load metadata for %s\n",
330 /* Ok, this is close enough. We can say goodbye to our parent now.
333 if (write(pfd
[1], &status
, sizeof(status
)) < 0)
334 fprintf(stderr
, "mdmon: failed to notify our parent: %d\n",
341 open("/dev/null", O_RDWR
);
349 mlockall(MCL_FUTURE
);
351 /* SIGUSR is sent between parent and child. So both block it
352 * and enable it only with pselect.
355 sigaddset(&set
, SIGUSR1
);
356 sigaddset(&set
, SIGHUP
);
357 sigaddset(&set
, SIGALRM
);
358 sigprocmask(SIG_BLOCK
, &set
, NULL
);
359 act
.sa_handler
= wake_me
;
361 sigaction(SIGUSR1
, &act
, NULL
);
362 sigaction(SIGALRM
, &act
, NULL
);
363 act
.sa_handler
= hup
;
364 sigaction(SIGHUP
, &act
, NULL
);
365 act
.sa_handler
= SIG_IGN
;
366 sigaction(SIGPIPE
, &act
, NULL
);
368 if (clone_monitor(container
) < 0) {
369 fprintf(stderr
, "mdmon: failed to start monitor process: %s\n",
374 do_manager(container
);