69b2fcc5bb
This is now only ever set, never used. So remove it. Signed-off-by: NeilBrown <neilb@suse.de>
520 lines
11 KiB
C
520 lines
11 KiB
C
/*
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* mdmon - monitor external metadata arrays
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*
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* Copyright (C) 2007-2009 Neil Brown <neilb@suse.de>
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* Copyright (C) 2007-2009 Intel Corporation
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms and conditions of the GNU General Public License,
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* version 2, as published by the Free Software Foundation.
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*
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* This program is distributed in the hope it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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* You should have received a copy of the GNU General Public License along with
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* this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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/*
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* md array manager.
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* When md arrays have user-space managed metadata, this is the program
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* that does the managing.
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*
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* Given one argument: the name of the array (e.g. /dev/md0) that is
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* the container.
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* We fork off a helper that runs high priority and mlocked. It responds to
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* device failures and other events that might stop writeout, or that are
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* trivial to deal with.
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* The main thread then watches for new arrays being created in the container
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* and starts monitoring them too ... along with a few other tasks.
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*
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* The main thread communicates with the priority thread by writing over
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* a pipe.
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* Separate programs can communicate with the main thread via Unix-domain
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* socket.
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* The two threads share address space and open file table.
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*
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*/
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#ifndef _GNU_SOURCE
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#define _GNU_SOURCE
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#endif
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#include <unistd.h>
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#include <stdlib.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <sys/socket.h>
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#include <sys/un.h>
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#include <sys/mman.h>
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#include <sys/syscall.h>
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#include <sys/wait.h>
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#include <stdio.h>
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#include <errno.h>
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#include <string.h>
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#include <fcntl.h>
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#include <signal.h>
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#include <dirent.h>
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#ifdef USE_PTHREADS
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#include <pthread.h>
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#else
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#include <sched.h>
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#endif
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#include "mdadm.h"
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#include "mdmon.h"
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struct active_array *discard_this;
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struct active_array *pending_discard;
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int mon_tid, mgr_tid;
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int sigterm;
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#ifdef USE_PTHREADS
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static void *run_child(void *v)
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{
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struct supertype *c = v;
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mon_tid = syscall(SYS_gettid);
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do_monitor(c);
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return 0;
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}
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static int clone_monitor(struct supertype *container)
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{
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pthread_attr_t attr;
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pthread_t thread;
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int rc;
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mon_tid = -1;
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pthread_attr_init(&attr);
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pthread_attr_setstacksize(&attr, 4096);
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pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
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rc = pthread_create(&thread, &attr, run_child, container);
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if (rc)
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return rc;
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while (mon_tid == -1)
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usleep(10);
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pthread_attr_destroy(&attr);
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mgr_tid = syscall(SYS_gettid);
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return mon_tid;
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}
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#else /* USE_PTHREADS */
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static int run_child(void *v)
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{
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struct supertype *c = v;
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do_monitor(c);
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return 0;
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}
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#ifdef __ia64__
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int __clone2(int (*fn)(void *),
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void *child_stack_base, size_t stack_size,
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int flags, void *arg, ...
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/* pid_t *pid, struct user_desc *tls, pid_t *ctid */ );
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#endif
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static int clone_monitor(struct supertype *container)
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{
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static char stack[4096];
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#ifdef __ia64__
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mon_tid = __clone2(run_child, stack, sizeof(stack),
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CLONE_FS|CLONE_FILES|CLONE_VM|CLONE_SIGHAND|CLONE_THREAD,
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container);
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#else
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mon_tid = clone(run_child, stack+4096-64,
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CLONE_FS|CLONE_FILES|CLONE_VM|CLONE_SIGHAND|CLONE_THREAD,
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container);
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#endif
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mgr_tid = syscall(SYS_gettid);
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return mon_tid;
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}
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#endif /* USE_PTHREADS */
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static int make_pidfile(char *devname)
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{
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char path[100];
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char pid[10];
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int fd;
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int n;
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if (mkdir(MDMON_DIR, 0755) < 0 &&
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errno != EEXIST)
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return -errno;
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sprintf(path, "%s/%s.pid", MDMON_DIR, devname);
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fd = open(path, O_RDWR|O_CREAT|O_EXCL, 0600);
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if (fd < 0)
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return -errno;
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sprintf(pid, "%d\n", getpid());
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n = write(fd, pid, strlen(pid));
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close(fd);
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if (n < 0)
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return -errno;
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return 0;
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}
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static void try_kill_monitor(pid_t pid, char *devname, int sock)
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{
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char buf[100];
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int fd;
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int n;
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long fl;
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/* first rule of survival... don't off yourself */
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if (pid == getpid())
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return;
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/* kill this process if it is mdmon */
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sprintf(buf, "/proc/%lu/cmdline", (unsigned long) pid);
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fd = open(buf, O_RDONLY);
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if (fd < 0)
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return;
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n = read(fd, buf, sizeof(buf)-1);
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buf[sizeof(buf)-1] = 0;
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close(fd);
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if (n < 0 || !strstr(buf, "mdmon"))
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return;
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kill(pid, SIGTERM);
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/* Wait for monitor to exit by reading from the socket, after
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* clearing the non-blocking flag */
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fl = fcntl(sock, F_GETFL, 0);
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fl &= ~O_NONBLOCK;
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fcntl(sock, F_SETFL, fl);
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n = read(sock, buf, 100);
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/* Ignore result, it is just the wait that
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* matters
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*/
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}
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void remove_pidfile(char *devname)
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{
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char buf[100];
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sprintf(buf, "%s/%s.pid", MDMON_DIR, devname);
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unlink(buf);
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sprintf(buf, "%s/%s.sock", MDMON_DIR, devname);
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unlink(buf);
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}
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static int make_control_sock(char *devname)
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{
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char path[100];
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int sfd;
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long fl;
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struct sockaddr_un addr;
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if (sigterm)
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return -1;
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sprintf(path, "%s/%s.sock", MDMON_DIR, devname);
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unlink(path);
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sfd = socket(PF_LOCAL, SOCK_STREAM, 0);
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if (sfd < 0)
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return -1;
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addr.sun_family = PF_LOCAL;
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strcpy(addr.sun_path, path);
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if (bind(sfd, &addr, sizeof(addr)) < 0) {
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close(sfd);
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return -1;
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}
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listen(sfd, 10);
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fl = fcntl(sfd, F_GETFL, 0);
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fl |= O_NONBLOCK;
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fcntl(sfd, F_SETFL, fl);
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return sfd;
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}
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static void term(int sig)
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{
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sigterm = 1;
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}
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static void wake_me(int sig)
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{
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}
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/* if we are debugging and starting mdmon by hand then don't fork */
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static int do_fork(void)
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{
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#ifdef DEBUG
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if (check_env("MDADM_NO_MDMON"))
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return 0;
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#endif
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return 1;
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}
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void usage(void)
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{
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fprintf(stderr, "Usage: mdmon [--all] [--takeover] CONTAINER\n");
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exit(2);
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}
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static int mdmon(char *devname, int devnum, int must_fork, int takeover);
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int main(int argc, char *argv[])
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{
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char *container_name = NULL;
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int devnum;
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char *devname;
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int status = 0;
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int arg;
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int all = 0;
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int takeover = 0;
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for (arg = 1; arg < argc; arg++) {
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if (strncmp(argv[arg], "--all",5) == 0 ||
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strcmp(argv[arg], "/proc/mdstat") == 0) {
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container_name = argv[arg];
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all = 1;
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} else if (strcmp(argv[arg], "--takeover") == 0)
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takeover = 1;
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else if (container_name == NULL)
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container_name = argv[arg];
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else
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usage();
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}
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if (container_name == NULL)
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usage();
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if (all) {
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struct mdstat_ent *mdstat, *e;
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int container_len = strlen(container_name);
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/* launch an mdmon instance for each container found */
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mdstat = mdstat_read(0, 0);
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for (e = mdstat; e; e = e->next) {
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if (strncmp(e->metadata_version, "external:", 9) == 0 &&
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!is_subarray(&e->metadata_version[9])) {
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devname = devnum2devname(e->devnum);
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/* update cmdline so this mdmon instance can be
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* distinguished from others in a call to ps(1)
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*/
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if (strlen(devname) <= (unsigned)container_len) {
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memset(container_name, 0, container_len);
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sprintf(container_name, "%s", devname);
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}
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status |= mdmon(devname, e->devnum, 1,
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takeover);
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}
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}
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free_mdstat(mdstat);
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return status;
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} else if (strncmp(container_name, "md", 2) == 0) {
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devnum = devname2devnum(container_name);
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devname = devnum2devname(devnum);
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if (strcmp(container_name, devname) != 0)
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devname = NULL;
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} else {
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struct stat st;
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devnum = NoMdDev;
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if (stat(container_name, &st) == 0)
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devnum = stat2devnum(&st);
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if (devnum == NoMdDev)
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devname = NULL;
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else
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devname = devnum2devname(devnum);
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}
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if (!devname) {
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fprintf(stderr, "mdmon: %s is not a valid md device name\n",
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container_name);
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exit(1);
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}
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return mdmon(devname, devnum, do_fork(), takeover);
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}
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static int mdmon(char *devname, int devnum, int must_fork, int takeover)
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{
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int mdfd;
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struct mdinfo *mdi, *di;
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struct supertype *container;
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sigset_t set;
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struct sigaction act;
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int pfd[2];
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int status;
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int ignore;
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pid_t victim = -1;
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int victim_sock = -1;
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dprintf("starting mdmon for %s\n", devname);
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mdfd = open_dev(devnum);
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if (mdfd < 0) {
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fprintf(stderr, "mdmon: %s: %s\n", devname,
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strerror(errno));
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return 1;
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}
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if (md_get_version(mdfd) < 0) {
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fprintf(stderr, "mdmon: %s: Not an md device\n",
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devname);
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return 1;
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}
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/* Fork, and have the child tell us when they are ready */
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if (must_fork) {
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if (pipe(pfd) != 0) {
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fprintf(stderr, "mdmon: failed to create pipe\n");
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return 1;
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}
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switch(fork()) {
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case -1:
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fprintf(stderr, "mdmon: failed to fork: %s\n",
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strerror(errno));
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return 1;
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case 0: /* child */
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close(pfd[0]);
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break;
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default: /* parent */
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close(pfd[1]);
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if (read(pfd[0], &status, sizeof(status)) != sizeof(status)) {
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wait(&status);
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status = WEXITSTATUS(status);
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}
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return status;
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}
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} else
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pfd[0] = pfd[1] = -1;
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container = calloc(1, sizeof(*container));
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container->devnum = devnum;
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container->devname = devname;
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container->arrays = NULL;
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container->sock = -1;
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if (!container->devname) {
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fprintf(stderr, "mdmon: failed to allocate container name string\n");
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exit(3);
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}
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mdi = sysfs_read(mdfd, container->devnum, GET_VERSION|GET_LEVEL|GET_DEVS);
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if (!mdi) {
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fprintf(stderr, "mdmon: failed to load sysfs info for %s\n",
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container->devname);
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exit(3);
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}
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if (mdi->array.level != UnSet) {
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fprintf(stderr, "mdmon: %s is not a container - cannot monitor\n",
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devname);
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exit(3);
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}
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if (mdi->array.major_version != -1 ||
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mdi->array.minor_version != -2) {
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fprintf(stderr, "mdmon: %s does not use external metadata - cannot monitor\n",
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devname);
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exit(3);
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}
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container->ss = version_to_superswitch(mdi->text_version);
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if (container->ss == NULL) {
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fprintf(stderr, "mdmon: %s uses unsupported metadata: %s\n",
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devname, mdi->text_version);
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exit(3);
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}
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container->devs = NULL;
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for (di = mdi->devs; di; di = di->next) {
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struct mdinfo *cd = malloc(sizeof(*cd));
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*cd = *di;
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cd->next = container->devs;
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container->devs = cd;
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}
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sysfs_free(mdi);
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/* SIGUSR is sent between parent and child. So both block it
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* and enable it only with pselect.
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*/
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sigemptyset(&set);
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sigaddset(&set, SIGUSR1);
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sigaddset(&set, SIGTERM);
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sigprocmask(SIG_BLOCK, &set, NULL);
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act.sa_handler = wake_me;
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act.sa_flags = 0;
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sigaction(SIGUSR1, &act, NULL);
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act.sa_handler = term;
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sigaction(SIGTERM, &act, NULL);
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act.sa_handler = SIG_IGN;
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sigaction(SIGPIPE, &act, NULL);
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victim = mdmon_pid(container->devnum);
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if (victim >= 0)
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victim_sock = connect_monitor(container->devname);
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ignore = chdir("/");
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if (!takeover && victim > 0 && victim_sock >= 0) {
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if (fping_monitor(victim_sock) == 0) {
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fprintf(stderr, "mdmon: %s already managed\n",
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container->devname);
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exit(3);
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}
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close(victim_sock);
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}
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if (container->ss->load_super(container, mdfd, devname)) {
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fprintf(stderr, "mdmon: Cannot load metadata for %s\n",
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devname);
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exit(3);
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}
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close(mdfd);
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/* Ok, this is close enough. We can say goodbye to our parent now.
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*/
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if (victim > 0)
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remove_pidfile(devname);
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if (make_pidfile(devname) < 0) {
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exit(3);
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}
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container->sock = make_control_sock(devname);
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status = 0;
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if (write(pfd[1], &status, sizeof(status)) < 0)
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fprintf(stderr, "mdmon: failed to notify our parent: %d\n",
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getppid());
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close(pfd[1]);
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mlockall(MCL_CURRENT | MCL_FUTURE);
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if (clone_monitor(container) < 0) {
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fprintf(stderr, "mdmon: failed to start monitor process: %s\n",
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strerror(errno));
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exit(2);
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}
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if (victim > 0) {
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try_kill_monitor(victim, container->devname, victim_sock);
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close(victim_sock);
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}
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setsid();
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close(0);
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open("/dev/null", O_RDWR);
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close(1);
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ignore = dup(0);
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#ifndef DEBUG
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close(2);
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ignore = dup(0);
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#endif
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do_manager(container);
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exit(0);
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}
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