scripts/lvm2_activation_generator_systemd_red_hat.c

   1 /*
   2  * Copyright (C) 2012 Red Hat, Inc. All rights reserved.
   3  *
   4  * This file is part of the device-mapper userspace tools.
   5  *
   6  * This copyrighted material is made available to anyone wishing to use,
   7  * modify, copy, or redistribute it subject to the terms and conditions
   8  * of the GNU General Public License v.2.
   9  *
  10  * You should have received a copy of the GNU General Public License
  11  * along with this program; if not, write to the Free Software Foundation,
  12  * Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  13 */
  14
  15 #include <stdio.h>
  16 #include <unistd.h>
  17 #include <errno.h>
  18 #include <stdarg.h>
  19 #include <sys/types.h>
  20 #include <sys/stat.h>
  21 #include <fcntl.h>
  22 #include "lvm2app.h"
  23
  24 #define KMSG_DEV_PATH        "/dev/kmsg"
  25 #define LVM_CONF_USE_LVMETAD "global/use_lvmetad"
  26
  27 #define DEFAULT_UNIT_DIR     "/tmp"
  28 #define UNIT_NAME_EARLY      "lvm2-activation-early.service"
  29 #define UNIT_NAME            "lvm2-activation.service"
  30 #define UNIT_TARGET          "local-fs.target"
  31
  32 static char unit_path[PATH_MAX];
  33 static char target_path[PATH_MAX];
  34 static char message[PATH_MAX];
  35 static int kmsg_fd = -1;
  36
  37 static void kmsg(const char *format, ...)
  38 {
  39         va_list ap;
  40         int n;
  41
  42         va_start(ap, format);
  43         n = vsnprintf(message, sizeof(message), format, ap);
  44         va_end(ap);
  45
  46         if (kmsg_fd < 0 || (n < 0 || ((unsigned) n + 1 > sizeof(message))))
  47                 return;
  48
  49         write(kmsg_fd, message, n + 1);
  50 }
  51
  52 static int lvm_uses_lvmetad(void)
  53 {
  54         lvm_t lvm;
  55         int r;
  56
  57         if (!(lvm = lvm_init(NULL))) {
  58                 kmsg("LVM: Failed to initialize library context for activation generator.\n");
  59                 return 0;
  60         }
  61         r = lvm_config_find_bool(lvm, LVM_CONF_USE_LVMETAD, 0);
  62         lvm_quit(lvm);
  63
  64         return r;
  65 }
  66
  67 static int register_unit_with_target(const char *dir, const char *unit, const char *target)
  68 {
  69         int r = 1;
  70
  71         if (dm_snprintf(target_path, PATH_MAX, "%s/%s.wants", dir, target) < 0) {
  72                 r = 0; goto out;
  73         }
  74         (void) dm_prepare_selinux_context(target_path, S_IFDIR);
  75         if (mkdir(target_path, 0755) < 0 && errno != EEXIST) {
  76                 kmsg("LVM: Failed to create target directory %s: %m.\n", target_path);
  77                 r = 0; goto out;
  78         }
  79
  80         if (dm_snprintf(target_path, PATH_MAX, "%s/%s.wants/%s", dir, target, unit) < 0) {
  81                 r = 0; goto out;
  82         }
  83         (void) dm_prepare_selinux_context(target_path, S_IFLNK);
  84         if (symlink(unit_path, target_path) < 0) {
  85                 kmsg("LVM: Failed to create symlink for unit %s: %m.\n", unit);
  86                 r = 0;
  87         }
  88 out:
  89         dm_prepare_selinux_context(NULL, 0);
  90         return r;
  91 }
  92
  93 static int generate_unit(const char *dir, int early)
  94 {
  95         FILE *f;
  96         const char *unit = early ? UNIT_NAME_EARLY : UNIT_NAME;
  97
  98         if (dm_snprintf(unit_path, PATH_MAX, "%s/%s", dir, unit) < 0)
  99                 return 0;
 100
 101         if (!(f = fopen(unit_path, "wxe"))) {
 102                 kmsg("LVM: Failed to create unit file %s: %m.\n", unit);
 103                 return 0;
 104         }
 105
 106         fputs("# Automatically generated by lvm2-activation-generator.\n"
 107               "#\n"
 108               "# This unit is responsible for direct activation of LVM2 logical volumes\n"
 109               "# if lvmetad daemon is not used (global/use_lvmetad=0 lvm.conf setting),\n"
 110               "# hence volume autoactivation is not applicable.\n"
 111               "# Direct LVM2 activation requires udev to be settled!\n\n"
 112               "[Unit]\n"
 113               "Description=Activation of LVM2 logical volumes\n"
 114               "Documentation=man:lvm(8) man:vgchange(8)\n"
 115               "SourcePath=/etc/lvm/lvm.conf\n"
 116               "DefaultDependencies=no\n", f);
 117
 118         if (early)
 119                 fputs("After=fedora-wait-storage.service\n", f);
 120         else
 121                 fputs("After=lvm2-activation-early.service cryptsetup.target\n", f);
 122
 123         fputs("Before=local-fs.target shutdown.target\n"
 124               "Wants=fedora-wait-storage.service\n\n"
 125               "[Service]\n"
 126               "ExecStart=/usr/sbin/lvm vgchange -aay --sysinit\n"
 127               "Type=oneshot\n", f);
 128
 129         if (fclose(f) < 0) {
 130                 kmsg("LVM: Failed to write unit file %s: %m.\n", unit);
 131                 return 0;
 132         }
 133
 134         if (!register_unit_with_target(dir, unit, UNIT_TARGET)) {
 135                 kmsg("LVM: Failed to register unit %s with target %s.\n", unit, UNIT_TARGET);
 136                 return 0;
 137         }
 138
 139         return 1;
 140 }
 141
 142 int main(int argc, char *argv[])
 143 {
 144         const char *dir;
 145         int r = EXIT_SUCCESS;
 146
 147         kmsg_fd = open(KMSG_DEV_PATH, O_WRONLY|O_NOCTTY);
 148
 149         if (argc > 1 && argc != 4) {
 150                 kmsg("LVM: Activation generator takes three or no arguments.\n");
 151                 r = EXIT_FAILURE; goto out;
 152         }
 153
 154         /* If lvmetad used, rely on autoactivation instead of direct activation. */
 155         if (lvm_uses_lvmetad()) {
 156                 kmsg("LVM: Logical Volume autoactivation enabled.\n");
 157                 goto out;
 158         }
 159
 160         dir = argc > 1 ? argv[1] : DEFAULT_UNIT_DIR;
 161
 162         if (!generate_unit(dir, 1) || !generate_unit(dir, 0))
 163                 r = EXIT_FAILURE;
 164 out:
 165         kmsg("LVM: Activation generator %s.\n", r ? "failed" : "successfully completed");
 166         if (kmsg_fd != -1)
 167                 close(kmsg_fd);
 168         return r;
 169 }