/* give the monitor a chance to update the metadata */
int ping_monitor(char *devname)
{
int sfd = connect_monitor(devname);
int err = fping_monitor(sfd);
close(sfd);
return err;
}
void connect_manager::start_monitor(int check_inter /* = 1 */,
int conn_timeout /* = 10 */)
{
if (monitor_ != NULL)
return;
monitor_ = NEW connect_monitor(*this, check_inter, conn_timeout);
// 设置检测线程为非分离模式，以便于主线程可以等待检测线程退出
monitor_->set_detachable(false);
// 启动检测线程
monitor_->start();
}
/* give the manager a chance to view the updated container state. This
* would naturally happen due to the manager noticing a change in
* /proc/mdstat; however, pinging encourages this detection to happen
* while an exclusive open() on the container is active
*/
int ping_manager(char *devname)
{
int sfd = connect_monitor(devname);
struct metadata_update msg = { .len = -1 };
int err = 0;
if (sfd < 0)
return sfd;
err = send_message(sfd, &msg, 20);
/* check the reply */
if (!err && wait_reply(sfd, 20) != 0)
err = -1;
close(sfd);
return err;
}
static char *ping_monitor_version(char *devname)
{
int sfd = connect_monitor(devname);
struct metadata_update msg;
int err = 0;
if (sfd < 0)
return NULL;
if (ack(sfd, 20) != 0)
err = -1;
if (!err && receive_message(sfd, &msg, 20) != 0)
err = -1;
close(sfd);
if (err || !msg.len || !msg.buf)
return NULL;
return msg.buf;
}
static int mdmon(char *devnm, int must_fork, int takeover)
{
int mdfd;
struct mdinfo *mdi, *di;
struct supertype *container;
sigset_t set;
struct sigaction act;
int pfd[2];
int status;
int ignore;
pid_t victim = -1;
int victim_sock = -1;
dprintf("starting mdmon for %s\n", devnm);
mdfd = open_dev(devnm);
if (mdfd < 0) {
pr_err("%s: %s\n", devnm, strerror(errno));
return 1;
}
if (md_get_version(mdfd) < 0) {
pr_err("%s: Not an md device\n", devnm);
return 1;
}
/* Fork, and have the child tell us when they are ready */
if (must_fork) {
if (pipe(pfd) != 0) {
pr_err("failed to create pipe\n");
return 1;
}
switch(fork()) {
case -1:
pr_err("failed to fork: %s\n", strerror(errno));
return 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);
}
close(pfd[0]);
return status;
}
} else
pfd[0] = pfd[1] = -1;
container = xcalloc(1, sizeof(*container));
strcpy(container->devnm, devnm);
container->arrays = NULL;
container->sock = -1;
mdi = sysfs_read(mdfd, container->devnm, GET_VERSION|GET_LEVEL|GET_DEVS);
if (!mdi) {
pr_err("failed to load sysfs info for %s\n", container->devnm);
exit(3);
}
if (mdi->array.level != UnSet) {
pr_err("%s is not a container - cannot monitor\n", devnm);
exit(3);
}
if (mdi->array.major_version != -1 ||
mdi->array.minor_version != -2) {
pr_err("%s does not use external metadata - cannot monitor\n",
devnm);
exit(3);
}
container->ss = version_to_superswitch(mdi->text_version);
if (container->ss == NULL) {
pr_err("%s uses unsupported metadata: %s\n",
devnm, mdi->text_version);
exit(3);
}
container->devs = NULL;
for (di = mdi->devs; di; di = di->next) {
struct mdinfo *cd = xmalloc(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, SIGTERM);
sigprocmask(SIG_BLOCK, &set, NULL);
act.sa_handler = wake_me;
act.sa_flags = 0;
sigaction(SIGUSR1, &act, NULL);
act.sa_handler = term;
sigaction(SIGTERM, &act, NULL);
act.sa_handler = SIG_IGN;
sigaction(SIGPIPE, &act, NULL);
victim = mdmon_pid(container->devnm);
if (victim >= 0)
victim_sock = connect_monitor(container->devnm);
ignore = chdir("/");
if (!takeover && victim > 0 && victim_sock >= 0) {
if (fping_monitor(victim_sock) == 0) {
pr_err("%s already managed\n", container->devnm);
exit(3);
}
close(victim_sock);
victim_sock = -1;
}
if (container->ss->load_container(container, mdfd, devnm)) {
pr_err("Cannot load metadata for %s\n", devnm);
exit(3);
}
close(mdfd);
/* Ok, this is close enough. We can say goodbye to our parent now.
*/
if (victim > 0)
remove_pidfile(devnm);
if (make_pidfile(devnm) < 0) {
exit(3);
}
container->sock = make_control_sock(devnm);
status = 0;
if (pfd[1] >= 0) {
if (write(pfd[1], &status, sizeof(status)) < 0)
pr_err("failed to notify our parent: %d\n",
getppid());
close(pfd[1]);
}
mlockall(MCL_CURRENT | MCL_FUTURE);
if (clone_monitor(container) < 0) {
pr_err("failed to start monitor process: %s\n",
strerror(errno));
exit(2);
}
if (victim > 0) {
try_kill_monitor(victim, container->devnm, victim_sock);
if (victim_sock >= 0)
close(victim_sock);
}
setsid();
close(0);
open("/dev/null", O_RDWR);
close(1);
ignore = dup(0);
#ifndef DEBUG
close(2);
ignore = dup(0);
#endif
/* This silliness is to stop the compiler complaining
* that we ignore 'ignore'
*/
if (ignore)
ignore++;
do_manager(container);
exit(0);
}
