]> git.ipfire.org Git - thirdparty/mdadm.git/blobdiff - mdmon.c
Having single function to read mdmon pid file.
[thirdparty/mdadm.git] / mdmon.c
diff --git a/mdmon.c b/mdmon.c
index d013dc8ffc9749a643beb4430d2da2a042b9e57c..d20bb3e490c01bbde2067bffb70c31ae50dcab04 100644 (file)
--- a/mdmon.c
+++ b/mdmon.c
@@ -1,3 +1,22 @@
+/*
+ * mdmon - monitor external metadata arrays
+ *
+ * Copyright (C) 2007-2009 Neil Brown <neilb@suse.de>
+ * Copyright (C) 2007-2009 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.
 
 #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 *array_list;
 struct active_array *discard_this;
 struct active_array *pending_discard;
-struct md_generic_cmd *active_cmd;
+
+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)
+#ifdef __ia64__
+int __clone2(int (*fn)(void *),
+           void *child_stack_base, size_t stack_size,
+           int flags, void *arg, ...
+        /* pid_t *pid, struct user_desc *tls, pid_t *ctid */ );
+#endif
+ int clone_monitor(struct supertype *container)
 {
        static char stack[4096];
-       int rv;
-
-       rv = pipe(container->mgr_pipe);
-       if (rv < 0)
-               return rv;
-       rv = pipe(container->mon_pipe);
-       if (rv < 0)
-               goto err_mon_pipe;
 
-       rv = clone(run_child, stack+4096-64,
+#ifdef __ia64__
+       mon_tid = __clone2(run_child, stack, sizeof(stack),
                   CLONE_FS|CLONE_FILES|CLONE_VM|CLONE_SIGHAND|CLONE_THREAD,
                   container);
-       if (rv < 0)
-               goto err_clone;
-       else
-               return rv;
-
- err_clone:
-       close(container->mon_pipe[0]);
-       close(container->mon_pipe[1]);
- err_mon_pipe:
-       close(container->mgr_pipe[0]);
-       close(container->mgr_pipe[1]);
-
-       return rv;
+#else
+       mon_tid = clone(run_child, stack+4096-64,
+                  CLONE_FS|CLONE_FILES|CLONE_VM|CLONE_SIGHAND|CLONE_THREAD,
+                  container);
+#endif
+
+       mgr_tid = syscall(SYS_gettid);
+
+       return mon_tid;
 }
 
 static struct superswitch *find_metadata_methods(char *vers)
 {
        if (strcmp(vers, "ddf") == 0)
                return &super_ddf;
+       if (strcmp(vers, "imsm") == 0)
+               return &super_imsm;
        return NULL;
 }
 
-
-static int make_pidfile(char *devname, int o_excl)
+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 -1;
+               return -errno;
        sprintf(pid, "%d\n", getpid());
-       write(fd, pid, strlen(pid));
+       n = write(fd, pid, strlen(pid));
        close(fd);
+       if (n < 0)
+               return -errno;
        return 0;
 }
 
-static void try_kill_monitor(char *devname)
+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;
+}
+
+static void try_kill_monitor(pid_t pid, char *devname, int sock)
 {
        char buf[100];
        int fd;
-       pid_t pid;
-
-       sprintf(buf, "/var/run/mdadm/%s.pid", devname);
-       fd = open(buf, O_RDONLY);
-       if (fd < 0)
-               return;
+       int n;
+       long fl;
 
-       if (read(fd, buf, sizeof(buf)) < 0) {
-               close(fd);
+       /* first rule of survival... don't off yourself */
+       if (pid == getpid())
                return;
-       }
-
-       close(fd);
-       pid = strtoul(buf, NULL, 10);
 
        /* kill this process if it is mdmon */
        sprintf(buf, "/proc/%lu/cmdline", (unsigned long) pid);
@@ -132,22 +165,46 @@ static void try_kill_monitor(char *devname)
        if (fd < 0)
                return;
 
-       if (read(fd, buf, sizeof(buf)) < 0) {
-               close(fd);
+       n = read(fd, buf, sizeof(buf)-1);
+       buf[sizeof(buf)-1] = 0;
+       close(fd);
+
+       if (n < 0 || !strstr(buf, "mdmon"))
                return;
-       }
 
-       if (strstr(buf, "mdmon") != NULL)
-               kill(pid, SIGTERM);
+       kill(pid, SIGTERM);
+
+       /* Wait for monitor to exit by reading from the socket, after
+        * clearing the non-blocking flag */
+       fl = fcntl(sock, F_GETFL, 0);
+       fl &= ~O_NONBLOCK;
+       fcntl(sock, F_SETFL, fl);
+       read(sock, buf, 100);
 }
 
-static int make_control_sock(char *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);
@@ -167,62 +224,216 @@ static int make_control_sock(char *devname)
        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 /device/name/for/container [target_dir]\n");
+       exit(2);
+}
+
+static int mdmon(char *devname, int devnum, int must_fork, char *switchroot);
+
 int main(int argc, char *argv[])
+{
+       char *container_name = NULL;
+       char *switchroot = NULL;
+       int devnum;
+       char *devname;
+       int status = 0;
+
+       switch (argc) {
+       case 3:
+               switchroot = argv[2];
+       case 2:
+               container_name = argv[1];
+               break;
+       default:
+               usage();
+       }
+
+       if (strcmp(container_name, "/proc/mdstat") == 0) {
+               struct mdstat_ent *mdstat, *e;
+
+               /* launch an mdmon instance for each container found */
+               mdstat = mdstat_read(0, 0);
+               for (e = mdstat; e; e = e->next) {
+                       if (strncmp(e->metadata_version, "external:", 9) == 0 &&
+                           !is_subarray(&e->metadata_version[9])) {
+                               devname = devnum2devname(e->devnum);
+                               /* update cmdline so this mdmon instance can be
+                                * distinguished from others in a call to ps(1)
+                                */
+                               if (strlen(devname) <= strlen(container_name)) {
+                                       memset(container_name, 0, strlen(container_name));
+                                       sprintf(container_name, "%s", devname);
+                               }
+                               status |= mdmon(devname, e->devnum, 1,
+                                               switchroot);
+                       }
+               }
+               free_mdstat(mdstat);
+
+               return status;
+       } else if (strncmp(container_name, "md", 2) == 0) {
+               devnum = devname2devnum(container_name);
+               devname = devnum2devname(devnum);
+               if (strcmp(container_name, devname) != 0)
+                       devname = NULL;
+       } else {
+               struct stat st;
+
+               devnum = NoMdDev;
+               if (stat(container_name, &st) == 0)
+                       devnum = stat2devnum(&st);
+               if (devnum == NoMdDev)
+                       devname = NULL;
+               else
+                       devname = devnum2devname(devnum);
+       }
+
+       if (!devname) {
+               fprintf(stderr, "mdmon: %s is not a valid md device name\n",
+                       container_name);
+               exit(1);
+       }
+       return mdmon(devname, devnum, do_fork(), switchroot);
+}
+
+static int mdmon(char *devname, int devnum, int must_fork, char *switchroot)
 {
        int mdfd;
        struct mdinfo *mdi, *di;
        struct supertype *container;
-       if (argc != 2) {
-               fprintf(stderr, "Usage: md-manage /device/name/for/container\n");
-               exit(2);
+       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 in %s\n",
+               devname, switchroot ? : "/");
+
+       /* switchroot is either a path name starting with '/', or a
+        * pid of the original mdmon (we have already done the chroot).
+        * In the latter case, stdin is a socket connected to the original
+        * mdmon.
+        */
+
+       /* try to spawn mdmon instances from the target file system */
+       if (switchroot && switchroot[0] == '/' &&
+           strcmp(switchroot, "/") != 0) {
+               pid_t pid;
+               char buf[20];
+
+               switch (fork()) {
+               case 0:
+                       victim = mdmon_pid(devnum);
+                       victim_sock = connect_monitor(devname);
+                       if (chroot(switchroot) != 0) {
+                               fprintf(stderr, "mdmon: failed to chroot to '%s': %s\n",
+                                       switchroot, strerror(errno));
+                               exit(4);
+                       }
+                       ignore = chdir("/");
+                       sprintf(buf, "%d", victim);
+                       if (victim_sock) {
+                               close(0);
+                               dup(victim_sock);
+                               close(victim_sock);
+                       }
+                       execl("/sbin/mdmon", "mdmon", devname, buf, NULL);
+                       exit(1);
+               case -1:
+                       return 1;
+               default:
+                       pid = wait(&status);
+                       if (pid > -1 && WIFEXITED(status) &&
+                           WEXITSTATUS(status) == 0)
+                               return 0;
+                       else
+                               return 1;
+               }
        }
-       mdfd = open(argv[1], O_RDWR);
+
+       mdfd = open_dev(devnum);
        if (mdfd < 0) {
-               fprintf(stderr, "md-manage: %s: %s\n", argv[1],
+               fprintf(stderr, "mdmon: %s: %s\n", devname,
                        strerror(errno));
-               exit(1);
+               return 1;
        }
        if (md_get_version(mdfd) < 0) {
-               fprintf(stderr, "md-manage: %s: Not an md device\n",
-                       argv[1]);
-               exit(1);
+               fprintf(stderr, "mdmon: %s: Not an md device\n",
+                       devname);
+               return 1;
        }
 
-       /* hopefully it is a container - we'll check later */
-
-       container = malloc(sizeof(*container));
-       container->devfd = mdfd;
-       container->devnum = fd2devnum(mdfd);
-       container->devname = devnum2devname(container->devnum);
-
-       /* If this fails, we hope it already exists */
-       mkdir("/var/run/mdadm", 0600);
-       /* pid file lives in /var/run/mdadm/mdXX.pid */
-       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 {
-                       /* cleanup the old monitor, this one is taking over */
-                       try_kill_monitor(container->devname);
-                       if (make_pidfile(container->devname, 0) < 0) {
-                               fprintf(stderr, "mdmon: %s Cannot create pidfile\n",
-                                       container->devname);
-                               exit(3);
+       /* Fork, and have the child tell us when they are ready */
+       if (must_fork) {
+               if (pipe(pfd) != 0) {
+                       fprintf(stderr, "mdmon: failed to create pipe\n");
+                       return 1;
+               }
+               switch(fork()) {
+               case -1:
+                       fprintf(stderr, "mdmon: 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);
                        }
+                       return status;
                }
-       }
+       } else
+               pfd[0] = pfd[1] = -1;
 
-       container->sock = make_control_sock(container->devname);
-       if (container->sock < 0) {
-               fprintf(stderr, "mdmon: Cannot create socket in /var/run/mdadm\n");
+       container = calloc(1, sizeof(*container));
+       container->devnum = devnum;
+       container->devname = devname;
+       container->arrays = NULL;
+       container->subarray[0] = 0;
+       container->sock = -1;
+
+       if (!container->devname) {
+               fprintf(stderr, "mdmon: failed to allocate container name string\n");
                exit(3);
        }
-       container->arrays = NULL;
 
        mdi = sysfs_read(mdfd, container->devnum,
-                        GET_VERSION|GET_LEVEL|GET_DEVS);
+                        GET_VERSION|GET_LEVEL|GET_DEVS|SKIP_GONE_DEVS);
 
        if (!mdi) {
                fprintf(stderr, "mdmon: failed to load sysfs info for %s\n",
@@ -231,48 +442,113 @@ int main(int argc, char *argv[])
        }
        if (mdi->array.level != UnSet) {
                fprintf(stderr, "mdmon: %s is not a container - cannot monitor\n",
-                       argv[1]);
+                       devname);
                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",
-                       argv[1]);
+                       devname);
                exit(3);
        }
 
        container->ss = find_metadata_methods(mdi->text_version);
        if (container->ss == NULL) {
                fprintf(stderr, "mdmon: %s uses unknown metadata: %s\n",
-                       argv[1], mdi->text_version);
+                       devname, 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 = *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
+                */
+               if (switchroot[0] == '/') {
+                       victim = mdmon_pid(container->devnum);
+                       victim_sock = connect_monitor(container->devname);
+               } else {
+                       victim = atoi(switchroot);
+                       victim_sock = 0;
+               }
+       }
 
-       if (container->ss->load_super(container, mdfd, argv[1])) {
+       ignore = chdir("/");
+       if (victim < 0) {
+               if (ping_monitor(container->devname) == 0) {
+                       fprintf(stderr, "mdmon: %s already managed\n",
+                               container->devname);
+                       exit(3);
+               }
+               /* if there is a pid file, kill whoever is there just in case */
+               victim = mdmon_pid(container->devnum);
+       }
+       if (container->ss->load_super(container, mdfd, devname)) {
                fprintf(stderr, "mdmon: Cannot load metadata for %s\n",
-                       argv[1]);
+                       devname);
                exit(3);
        }
+       close(mdfd);
 
+       /* 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]);
 
-       mlockall(MCL_FUTURE);
+       mlockall(MCL_CURRENT | MCL_FUTURE);
 
        if (clone_monitor(container) < 0) {
-               fprintf(stderr, "md-manage: failed to start monitor process: %s\n",
+               fprintf(stderr, "mdmon: failed to start monitor process: %s\n",
                        strerror(errno));
                exit(2);
        }
 
+       if (victim > -1) {
+               try_kill_monitor(victim, container->devname, victim_sock);
+               close(victim_sock);
+       }
+
+       setsid();
+       close(0);
+       open("/dev/null", O_RDWR);
+       close(1);
+       ignore = dup(0);
+#ifndef DEBUG
+       close(2);
+       ignore = dup(0);
+#endif
+
        do_manager(container);
 
        exit(0);