[thirdparty/mdadm.git] / mdmon.c

/*
 * mdmon - monitor external metadata arrays
 *
 * Copyright (C) 2007-2008 Neil Brown <neilb@suse.de>
 * Copyright (C) 2007-2008 Intel Corporation
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
 */

/*
 * md array manager.
 * When md arrays have user-space managed metadata, this is the program
 * that does the managing.
 *
 * Given one argument: the name of the array (e.g. /dev/md0) that is
 * the container.
 * We fork off a helper that runs high priority and mlocked.  It responds to
 * device failures and other events that might stop writeout, or that are
 * trivial to deal with.
 * The main thread then watches for new arrays being created in the container
 * and starts monitoring them too ... along with a few other tasks.
 *
 * The main thread communicates with the priority thread by writing over
 * a pipe.
 * Separate programs can communicate with the main thread via Unix-domain
 * socket.
 * The two threads share address space and open file table.
 *
 */

#ifndef _GNU_SOURCE
#define _GNU_SOURCE
#endif

#include	<unistd.h>
#include	<stdlib.h>
#include	<sys/types.h>
#include	<sys/stat.h>
#include	<sys/socket.h>
#include	<sys/un.h>
#include	<sys/mman.h>
#include	<sys/syscall.h>
#include	<sys/wait.h>
#include	<stdio.h>
#include	<errno.h>
#include	<string.h>
#include	<fcntl.h>
#include	<signal.h>
#include	<dirent.h>

#include	<sched.h>

#include	"mdadm.h"
#include	"mdmon.h"

struct active_array *discard_this;
struct active_array *pending_discard;

int mon_tid, mgr_tid;

int sigterm;

int run_child(void *v)
{
	struct supertype *c = v;

	do_monitor(c);
	return 0;
}

int clone_monitor(struct supertype *container)
{
	static char stack[4096];

	mon_tid = clone(run_child, stack+4096-64,
		   CLONE_FS|CLONE_FILES|CLONE_VM|CLONE_SIGHAND|CLONE_THREAD,
		   container);

	mgr_tid = syscall(SYS_gettid);

	return mon_tid;
}


int make_pidfile(char *devname, int o_excl)
{
	char path[100];
	char pid[10];
	int fd;
	int n;

	if (sigterm)
		return -1;

	sprintf(path, "/var/run/mdadm/%s.pid", devname);

	fd = open(path, O_RDWR|O_CREAT|o_excl, 0600);
	if (fd < 0)
		return -errno;
	sprintf(pid, "%d\n", getpid());
	n = write(fd, pid, strlen(pid));
	close(fd);
	if (n < 0)
		return -errno;
	return 0;
}

int is_container_member(struct mdstat_ent *mdstat, char *container)
{
	if (mdstat->metadata_version == NULL ||
	    strncmp(mdstat->metadata_version, "external:", 9) != 0 ||
	    !is_subarray(mdstat->metadata_version+9) ||
	    strncmp(mdstat->metadata_version+10, container, strlen(container)) != 0 ||
	    mdstat->metadata_version[10+strlen(container)] != '/')
		return 0;

	return 1;
}

void remove_pidfile(char *devname);
static void try_kill_monitor(char *devname)
{
	char buf[100];
	int fd;
	pid_t pid;
	struct mdstat_ent *mdstat;

	sprintf(buf, "/var/run/mdadm/%s.pid", devname);
	fd = open(buf, O_RDONLY);
	if (fd < 0)
		return;

	if (read(fd, buf, sizeof(buf)) < 0) {
		close(fd);
		return;
	}

	close(fd);
	pid = strtoul(buf, NULL, 10);

	/* first rule of survival... don't off yourself */
	if (pid == getpid())
		return;

	/* kill this process if it is mdmon */
	sprintf(buf, "/proc/%lu/cmdline", (unsigned long) pid);
	fd = open(buf, O_RDONLY);
	if (fd < 0)
		return;

	if (read(fd, buf, sizeof(buf)) < 0) {
		close(fd);
		return;
	}

	if (!strstr(buf, "mdmon"))
		return;

	kill(pid, SIGTERM);

	mdstat = mdstat_read(0, 0);
	for ( ; mdstat; mdstat = mdstat->next)
		if (is_container_member(mdstat, devname)) {
			sprintf(buf, "/dev/%s", mdstat->dev);
			WaitClean(buf, 0);
		}
	free_mdstat(mdstat);
	remove_pidfile(devname);
}

void remove_pidfile(char *devname)
{
	char buf[100];

	if (sigterm)
		return;

	sprintf(buf, "/var/run/mdadm/%s.pid", devname);
	unlink(buf);
	sprintf(buf, "/var/run/mdadm/%s.sock", devname);
	unlink(buf);
}

int make_control_sock(char *devname)
{
	char path[100];
	int sfd;
	long fl;
	struct sockaddr_un addr;

	if (sigterm)
		return -1;

	sprintf(path, "/var/run/mdadm/%s.sock", devname);
	unlink(path);
	sfd = socket(PF_LOCAL, SOCK_STREAM, 0);
	if (sfd < 0)
		return -1;

	addr.sun_family = PF_LOCAL;
	strcpy(addr.sun_path, path);
	if (bind(sfd, &addr, sizeof(addr)) < 0) {
		close(sfd);
		return -1;
	}
	listen(sfd, 10);
	fl = fcntl(sfd, F_GETFL, 0);
	fl |= O_NONBLOCK;
	fcntl(sfd, F_SETFL, fl);
	return sfd;
}

int socket_hup_requested;
static void hup(int sig)
{
	socket_hup_requested = 1;
}

static void term(int sig)
{
	sigterm = 1;
}

static void wake_me(int sig)
{

}

/* if we are debugging and starting mdmon by hand then don't fork */
static int do_fork(void)
{
	#ifdef DEBUG
	if (check_env("MDADM_NO_MDMON"))
		return 0;
	#endif

	return 1;
}

void usage(void)
{
	fprintf(stderr, "Usage: mdmon [--switch-root dir] /device/name/for/container\n");
	exit(2);
}

int main(int argc, char *argv[])
{
	int mdfd;
	struct mdinfo *mdi, *di;
	struct supertype *container;
	sigset_t set;
	struct sigaction act;
	int pfd[2];
	int status;
	int ignore;
	char *container_name = NULL;
	char *switchroot = NULL;

	switch (argc) {
	case 2:
		container_name = argv[1];
		break;
	case 4:
		if (strcmp(argv[1], "--switch-root") != 0) {
			fprintf(stderr, "mdmon: unknown argument %s\n", argv[1]);
			usage();
		}
		switchroot = argv[2];
		container_name = argv[3];
		break;
	default:
		usage();
	}

	mdfd = open(container_name, O_RDWR);
	if (mdfd < 0) {
		fprintf(stderr, "mdmon: %s: %s\n", container_name,
			strerror(errno));
		exit(1);
	}
	if (md_get_version(mdfd) < 0) {
		fprintf(stderr, "mdmon: %s: Not an md device\n",
			container_name);
		exit(1);
	}

	/* Fork, and have the child tell us when they are ready */
	if (do_fork()) {
		if (pipe(pfd) != 0) {
			fprintf(stderr, "mdmon: failed to create pipe\n");
			exit(1);
		}
		switch(fork()) {
		case -1:
			fprintf(stderr, "mdmon: failed to fork: %s\n",
				strerror(errno));
			exit(1);
		case 0: /* child */
			close(pfd[0]);
			break;
		default: /* parent */
			close(pfd[1]);
			if (read(pfd[0], &status, sizeof(status)) != sizeof(status)) {
				wait(&status);
				status = WEXITSTATUS(status);
			}
			exit(status);
		}
	} else
		pfd[0] = pfd[1] = -1;

	container = malloc(sizeof(*container));
	container->devnum = fd2devnum(mdfd);
	container->devname = devnum2devname(container->devnum);
	container->device_name = container_name;
	container->arrays = NULL;

	if (!container->devname) {
		fprintf(stderr, "mdmon: failed to allocate container name string\n");
		exit(3);
	}

	mdi = sysfs_read(mdfd, container->devnum,
			 GET_VERSION|GET_LEVEL|GET_DEVS);

	if (!mdi) {
		fprintf(stderr, "mdmon: failed to load sysfs info for %s\n",
			container->devname);
		exit(3);
	}
	if (mdi->array.level != UnSet) {
		fprintf(stderr, "mdmon: %s is not a container - cannot monitor\n",
			container_name);
		exit(3);
	}
	if (mdi->array.major_version != -1 ||
	    mdi->array.minor_version != -2) {
		fprintf(stderr, "mdmon: %s does not use external metadata - cannot monitor\n",
			container_name);
		exit(3);
	}

	container->ss = find_metadata_methods(mdi->text_version);
	if (container->ss == NULL) {
		fprintf(stderr, "mdmon: %s uses unknown metadata: %s\n",
			container_name, mdi->text_version);
		exit(3);
	}

	container->devs = NULL;
	for (di = mdi->devs; di; di = di->next) {
		struct mdinfo *cd = malloc(sizeof(*cd));
		*cd = *di;
		cd->next = container->devs;
		container->devs = cd;
	}
	sysfs_free(mdi);

	/* SIGUSR is sent between parent and child.  So both block it
	 * and enable it only with pselect.
	 */
	sigemptyset(&set);
	sigaddset(&set, SIGUSR1);
	sigaddset(&set, SIGHUP);
	sigaddset(&set, SIGALRM);
	sigaddset(&set, SIGTERM);
	sigprocmask(SIG_BLOCK, &set, NULL);
	act.sa_handler = wake_me;
	act.sa_flags = 0;
	sigaction(SIGUSR1, &act, NULL);
	sigaction(SIGALRM, &act, NULL);
	act.sa_handler = hup;
	sigaction(SIGHUP, &act, NULL);
	act.sa_handler = term;
	sigaction(SIGTERM, &act, NULL);
	act.sa_handler = SIG_IGN;
	sigaction(SIGPIPE, &act, NULL);

	if (switchroot) {
		/* we assume we assume that /sys /proc /dev are available in
		 * the new root (see nash:setuproot)
		 *
		 * kill any monitors in the current namespace and change
		 * to the new one
		 */
		try_kill_monitor(container->devname);
		if (chroot(switchroot) != 0) {
			fprintf(stderr, "mdmon: failed to chroot to '%s': %s\n",
				switchroot, strerror(errno));
			exit(4);
		}
	}

	/* If this fails, we hope it already exists 
	 * pid file lives in /var/run/mdadm/mdXX.pid
	 */
	mkdir("/var", 0600);
	mkdir("/var/run", 0600);
	mkdir("/var/run/mdadm", 0600);
	ignore = chdir("/");
	if (make_pidfile(container->devname, O_EXCL) < 0) {
		if (ping_monitor(container->devname) == 0) {
			fprintf(stderr, "mdmon: %s already managed\n",
				container->devname);
			exit(3);
		} else {
			int err;

			/* cleanup the old monitor, this one is taking over */
			try_kill_monitor(container->devname);
			err = make_pidfile(container->devname, 0);
			if (err < 0) {
				fprintf(stderr, "mdmon: %s Cannot create pidfile\n",
					container->devname);
				if (err == -EROFS) {
					/* FIXME implement a mechanism to
					 * prevent duplicate monitor instances
					 */
					fprintf(stderr,
						"mdmon: continuing on read-only file system\n");
				} else
					exit(3);
			}
		}
	}
	container->sock = make_control_sock(container->devname);

	if (container->ss->load_super(container, mdfd, container_name)) {
		fprintf(stderr, "mdmon: Cannot load metadata for %s\n",
			container_name);
		exit(3);
	}

	/* Ok, this is close enough.  We can say goodbye to our parent now.
	 */
	status = 0;
	if (write(pfd[1], &status, sizeof(status)) < 0)
		fprintf(stderr, "mdmon: failed to notify our parent: %d\n",
			getppid());
	close(pfd[1]);

	setsid();
	close(0);
	open("/dev/null", O_RDWR);
	close(1);
	ignore = dup(0);
#ifndef DEBUG
	close(2);
	ignore = dup(0);
#endif

	mlockall(MCL_FUTURE);

	if (clone_monitor(container) < 0) {
		fprintf(stderr, "mdmon: failed to start monitor process: %s\n",
			strerror(errno));
		exit(2);
	}

	do_manager(container);

	exit(0);
}
Commit	Line	Data
a54d5262 DW	1	/*
	2	* mdmon - monitor external metadata arrays
	3	*
	4	* Copyright (C) 2007-2008 Neil Brown <neilb@suse.de>
	5	* Copyright (C) 2007-2008 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	*/
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	67	struct active_array *discard_this;
549e9569 NB	68	struct active_array *pending_discard;
4d43913c NB	69
4d43913c NB	70	int mon_tid, mgr_tid;
549e9569	71
6144ed44 DW	72	int sigterm;
6144ed44 DW	73
549e9569 NB	74	int run_child(void *v)
	75	{
	76	struct supertype *c = v;
1ed3f387	77
549e9569 NB	78	do_monitor(c);
	79	return 0;
	80	}
	81
	82	int clone_monitor(struct supertype *container)
	83	{
549e9569	84	static char stack[4096];
549e9569	85
2cc98f9e	86	mon_tid = clone(run_child, stack+4096-64,
549e9569 NB	87	CLONE_FS\|CLONE_FILES\|CLONE_VM\|CLONE_SIGHAND\|CLONE_THREAD,
549e9569 NB	88	container);
3e70c845	89
4d43913c	90	mgr_tid = syscall(SYS_gettid);
2cc98f9e DW	91
2cc98f9e DW	92	return mon_tid;
549e9569 NB	93	}
549e9569 NB	94
549e9569	95
295646b3	96	int make_pidfile(char *devname, int o_excl)
549e9569 NB	97	{
	98	char path[100];
	99	char pid[10];
	100	int fd;
3d2c4fc7 DW	101	int n;
3d2c4fc7 DW	102
6144ed44 DW	103	if (sigterm)
	104	return -1;
	105
549e9569 NB	106	sprintf(path, "/var/run/mdadm/%s.pid", devname);
549e9569 NB	107
b109d928	108	fd = open(path, O_RDWR\|O_CREAT\|o_excl, 0600);
549e9569	109	if (fd < 0)
295646b3	110	return -errno;
549e9569	111	sprintf(pid, "%d\n", getpid());
3d2c4fc7	112	n = write(fd, pid, strlen(pid));
549e9569	113	close(fd);
3d2c4fc7 DW	114	if (n < 0)
3d2c4fc7 DW	115	return -errno;
549e9569 NB	116	return 0;
	117	}
	118
883a6142 DW	119	int is_container_member(struct mdstat_ent mdstat, char container)
	120	{
	121	if (mdstat->metadata_version == NULL \|\|
	122	strncmp(mdstat->metadata_version, "external:", 9) != 0 \|\|
	123	!is_subarray(mdstat->metadata_version+9) \|\|
	124	strncmp(mdstat->metadata_version+10, container, strlen(container)) != 0 \|\|
	125	mdstat->metadata_version[10+strlen(container)] != '/')
	126	return 0;
	127
	128	return 1;
	129	}
	130
	131	void remove_pidfile(char *devname);
b109d928 DW	132	static void try_kill_monitor(char *devname)
	133	{
	134	char buf[100];
	135	int fd;
	136	pid_t pid;
883a6142	137	struct mdstat_ent *mdstat;
b109d928 DW	138
	139	sprintf(buf, "/var/run/mdadm/%s.pid", devname);
	140	fd = open(buf, O_RDONLY);
	141	if (fd < 0)
	142	return;
	143
	144	if (read(fd, buf, sizeof(buf)) < 0) {
	145	close(fd);
	146	return;
	147	}
	148
	149	close(fd);
	150	pid = strtoul(buf, NULL, 10);
	151
8aae4219 DW	152	/* first rule of survival... don't off yourself */
	153	if (pid == getpid())
	154	return;
	155
b109d928 DW	156	/* kill this process if it is mdmon */
	157	sprintf(buf, "/proc/%lu/cmdline", (unsigned long) pid);
	158	fd = open(buf, O_RDONLY);
	159	if (fd < 0)
	160	return;
	161
	162	if (read(fd, buf, sizeof(buf)) < 0) {
	163	close(fd);
	164	return;
	165	}
	166
883a6142 DW	167	if (!strstr(buf, "mdmon"))
	168	return;
	169
	170	kill(pid, SIGTERM);
	171
	172	mdstat = mdstat_read(0, 0);
	173	for ( ; mdstat; mdstat = mdstat->next)
	174	if (is_container_member(mdstat, devname)) {
	175	sprintf(buf, "/dev/%s", mdstat->dev);
27dec8fa	176	WaitClean(buf, 0);
883a6142 DW	177	}
	178	free_mdstat(mdstat);
	179	remove_pidfile(devname);
b109d928 DW	180	}
b109d928 DW	181
e0d6609f NB	182	void remove_pidfile(char *devname)
	183	{
	184	char buf[100];
	185
6144ed44 DW	186	if (sigterm)
	187	return;
	188
e0d6609f NB	189	sprintf(buf, "/var/run/mdadm/%s.pid", devname);
e0d6609f NB	190	unlink(buf);
57752795 N	191	sprintf(buf, "/var/run/mdadm/%s.sock", devname);
57752795 N	192	unlink(buf);
e0d6609f NB	193	}
e0d6609f NB	194
295646b3	195	int make_control_sock(char *devname)
549e9569 NB	196	{
	197	char path[100];
	198	int sfd;
	199	long fl;
	200	struct sockaddr_un addr;
	201
6144ed44 DW	202	if (sigterm)
	203	return -1;
	204
549e9569 NB	205	sprintf(path, "/var/run/mdadm/%s.sock", devname);
	206	unlink(path);
	207	sfd = socket(PF_LOCAL, SOCK_STREAM, 0);
	208	if (sfd < 0)
	209	return -1;
	210
	211	addr.sun_family = PF_LOCAL;
	212	strcpy(addr.sun_path, path);
	213	if (bind(sfd, &addr, sizeof(addr)) < 0) {
	214	close(sfd);
	215	return -1;
	216	}
	217	listen(sfd, 10);
	218	fl = fcntl(sfd, F_GETFL, 0);
	219	fl \|= O_NONBLOCK;
	220	fcntl(sfd, F_SETFL, fl);
	221	return sfd;
	222	}
	223
295646b3 DW	224	int socket_hup_requested;
	225	static void hup(int sig)
	226	{
	227	socket_hup_requested = 1;
	228	}
	229
6144ed44 DW	230	static void term(int sig)
	231	{
	232	sigterm = 1;
	233	}
	234
4d43913c NB	235	static void wake_me(int sig)
	236	{
	237
	238	}
	239
16ddab0d DW	240	/* if we are debugging and starting mdmon by hand then don't fork */
	241	static int do_fork(void)
	242	{
	243	#ifdef DEBUG
40ebbb9c	244	if (check_env("MDADM_NO_MDMON"))
16ddab0d DW	245	return 0;
	246	#endif
	247
	248	return 1;
	249	}
	250
13047e4c DW	251	void usage(void)
	252	{
	253	fprintf(stderr, "Usage: mdmon [--switch-root dir] /device/name/for/container\n");
	254	exit(2);
	255	}
16ddab0d	256
549e9569 NB	257	int main(int argc, char *argv[])
	258	{
	259	int mdfd;
549e9569 NB	260	struct mdinfo mdi, di;
549e9569 NB	261	struct supertype *container;
4d43913c	262	sigset_t set;
bfa44e2e	263	struct sigaction act;
9fe32043 N	264	int pfd[2];
9fe32043 N	265	int status;
3d2c4fc7	266	int ignore;
13047e4c DW	267	char *container_name = NULL;
	268	char *switchroot = NULL;
	269
	270	switch (argc) {
	271	case 2:
	272	container_name = argv[1];
	273	break;
	274	case 4:
	275	if (strcmp(argv[1], "--switch-root") != 0) {
	276	fprintf(stderr, "mdmon: unknown argument %s\n", argv[1]);
	277	usage();
	278	}
	279	switchroot = argv[2];
	280	container_name = argv[3];
	281	break;
	282	default:
	283	usage();
549e9569	284	}
13047e4c DW	285
13047e4c DW	286	mdfd = open(container_name, O_RDWR);
549e9569	287	if (mdfd < 0) {
13047e4c	288	fprintf(stderr, "mdmon: %s: %s\n", container_name,
549e9569 NB	289	strerror(errno));
	290	exit(1);
	291	}
	292	if (md_get_version(mdfd) < 0) {
13047e4c DW	293	fprintf(stderr, "mdmon: %s: Not an md device\n",
13047e4c DW	294	container_name);
549e9569 NB	295	exit(1);
	296	}
	297
9fe32043	298	/* Fork, and have the child tell us when they are ready */
16ddab0d	299	if (do_fork()) {
3d2c4fc7 DW	300	if (pipe(pfd) != 0) {
	301	fprintf(stderr, "mdmon: failed to create pipe\n");
	302	exit(1);
	303	}
16ddab0d DW	304	switch(fork()) {
	305	case -1:
	306	fprintf(stderr, "mdmon: failed to fork: %s\n",
	307	strerror(errno));
	308	exit(1);
	309	case 0: /* child */
	310	close(pfd[0]);
	311	break;
	312	default: /* parent */
	313	close(pfd[1]);
	314	if (read(pfd[0], &status, sizeof(status)) != sizeof(status)) {
	315	wait(&status);
	316	status = WEXITSTATUS(status);
	317	}
	318	exit(status);
9fe32043	319	}
16ddab0d DW	320	} else
16ddab0d DW	321	pfd[0] = pfd[1] = -1;
549e9569 NB	322
549e9569 NB	323	container = malloc(sizeof(*container));
549e9569 NB	324	container->devnum = fd2devnum(mdfd);
549e9569 NB	325	container->devname = devnum2devname(container->devnum);
13047e4c DW	326	container->device_name = container_name;
	327	container->arrays = NULL;
	328
	329	if (!container->devname) {
	330	fprintf(stderr, "mdmon: failed to allocate container name string\n");
	331	exit(3);
	332	}
	333
	334	mdi = sysfs_read(mdfd, container->devnum,
	335	GET_VERSION\|GET_LEVEL\|GET_DEVS);
	336
	337	if (!mdi) {
	338	fprintf(stderr, "mdmon: failed to load sysfs info for %s\n",
	339	container->devname);
	340	exit(3);
	341	}
	342	if (mdi->array.level != UnSet) {
	343	fprintf(stderr, "mdmon: %s is not a container - cannot monitor\n",
	344	container_name);
	345	exit(3);
	346	}
	347	if (mdi->array.major_version != -1 \|\|
	348	mdi->array.minor_version != -2) {
	349	fprintf(stderr, "mdmon: %s does not use external metadata - cannot monitor\n",
	350	container_name);
	351	exit(3);
	352	}
	353
	354	container->ss = find_metadata_methods(mdi->text_version);
	355	if (container->ss == NULL) {
	356	fprintf(stderr, "mdmon: %s uses unknown metadata: %s\n",
	357	container_name, mdi->text_version);
	358	exit(3);
	359	}
	360
	361	container->devs = NULL;
	362	for (di = mdi->devs; di; di = di->next) {
	363	struct mdinfo cd = malloc(sizeof(cd));
	364	cd = di;
	365	cd->next = container->devs;
	366	container->devs = cd;
	367	}
	368	sysfs_free(mdi);
549e9569	369
883a6142 DW	370	/* SIGUSR is sent between parent and child. So both block it
	371	* and enable it only with pselect.
	372	*/
	373	sigemptyset(&set);
	374	sigaddset(&set, SIGUSR1);
	375	sigaddset(&set, SIGHUP);
	376	sigaddset(&set, SIGALRM);
	377	sigaddset(&set, SIGTERM);
	378	sigprocmask(SIG_BLOCK, &set, NULL);
	379	act.sa_handler = wake_me;
	380	act.sa_flags = 0;
	381	sigaction(SIGUSR1, &act, NULL);
	382	sigaction(SIGALRM, &act, NULL);
	383	act.sa_handler = hup;
	384	sigaction(SIGHUP, &act, NULL);
	385	act.sa_handler = term;
	386	sigaction(SIGTERM, &act, NULL);
	387	act.sa_handler = SIG_IGN;
	388	sigaction(SIGPIPE, &act, NULL);
	389
13047e4c DW	390	if (switchroot) {
	391	/* we assume we assume that /sys /proc /dev are available in
	392	* the new root (see nash:setuproot)
	393	*
	394	* kill any monitors in the current namespace and change
	395	* to the new one
	396	*/
	397	try_kill_monitor(container->devname);
	398	if (chroot(switchroot) != 0) {
	399	fprintf(stderr, "mdmon: failed to chroot to '%s': %s\n",
	400	switchroot, strerror(errno));
	401	exit(4);
	402	}
	403	}
	404
	405	/* If this fails, we hope it already exists
	406	* pid file lives in /var/run/mdadm/mdXX.pid
	407	*/
	408	mkdir("/var", 0600);
	409	mkdir("/var/run", 0600);
549e9569	410	mkdir("/var/run/mdadm", 0600);
13047e4c	411	ignore = chdir("/");
b109d928 DW	412	if (make_pidfile(container->devname, O_EXCL) < 0) {
	413	if (ping_monitor(container->devname) == 0) {
	414	fprintf(stderr, "mdmon: %s already managed\n",
	415	container->devname);
	416	exit(3);
	417	} else {
295646b3 DW	418	int err;
295646b3 DW	419
b109d928 DW	420	/* cleanup the old monitor, this one is taking over */
b109d928 DW	421	try_kill_monitor(container->devname);
295646b3 DW	422	err = make_pidfile(container->devname, 0);
295646b3 DW	423	if (err < 0) {
b109d928 DW	424	fprintf(stderr, "mdmon: %s Cannot create pidfile\n",
b109d928 DW	425	container->devname);
295646b3 DW	426	if (err == -EROFS) {
	427	/* FIXME implement a mechanism to
	428	* prevent duplicate monitor instances
	429	*/
	430	fprintf(stderr,
	431	"mdmon: continuing on read-only file system\n");
	432	} else
	433	exit(3);
b109d928 DW	434	}
b109d928 DW	435	}
549e9569	436	}
549e9569	437	container->sock = make_control_sock(container->devname);
549e9569	438
13047e4c	439	if (container->ss->load_super(container, mdfd, container_name)) {
549e9569	440	fprintf(stderr, "mdmon: Cannot load metadata for %s\n",
13047e4c	441	container_name);
549e9569 NB	442	exit(3);
549e9569 NB	443	}
549e9569	444
9fe32043 N	445	/* Ok, this is close enough. We can say goodbye to our parent now.
	446	*/
	447	status = 0;
3d2c4fc7 DW	448	if (write(pfd[1], &status, sizeof(status)) < 0)
	449	fprintf(stderr, "mdmon: failed to notify our parent: %d\n",
	450	getppid());
9fe32043 N	451	close(pfd[1]);
9fe32043 N	452
9fe32043 N	453	setsid();
	454	close(0);
	455	open("/dev/null", O_RDWR);
	456	close(1);
3d2c4fc7	457	ignore = dup(0);
9fe32043 N	458	#ifndef DEBUG
9fe32043 N	459	close(2);
3d2c4fc7	460	ignore = dup(0);
9fe32043 N	461	#endif
9fe32043 N	462
549e9569 NB	463	mlockall(MCL_FUTURE);
549e9569 NB	464
3e70c845	465	if (clone_monitor(container) < 0) {
295646b3	466	fprintf(stderr, "mdmon: failed to start monitor process: %s\n",
549e9569 NB	467	strerror(errno));
	468	exit(2);
	469	}
	470
	471	do_manager(container);
	472
	473	exit(0);
	474	}