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lvm2/scripts/lvm2_activation_generator_systemd_red_hat.c
2013-06-15 01:28:54 +01:00

173 lines
4.7 KiB
C

/*
* Copyright (C) 2012 Red Hat, Inc. All rights reserved.
*
* This file is part of the device-mapper userspace tools.
*
* This copyrighted material is made available to anyone wishing to use,
* modify, copy, or redistribute it subject to the terms and conditions
* of the GNU General Public License v.2.
*
* 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <stdio.h>
#include <unistd.h>
#include <errno.h>
#include <stdarg.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <limits.h> /* For PATH_MAX for musl libc */
#include "lvm2app.h"
#define KMSG_DEV_PATH "/dev/kmsg"
#define LVM_CONF_USE_LVMETAD "global/use_lvmetad"
#define DEFAULT_UNIT_DIR "/tmp"
#define UNIT_NAME_EARLY "lvm2-activation-early.service"
#define UNIT_NAME "lvm2-activation.service"
#define UNIT_TARGET "local-fs.target"
static char unit_path[PATH_MAX];
static char target_path[PATH_MAX];
static char message[PATH_MAX];
static int kmsg_fd = -1;
__attribute__ ((format(printf, 1, 2)))
static void kmsg(const char *format, ...)
{
va_list ap;
int n;
va_start(ap, format);
n = vsnprintf(message, sizeof(message), format, ap);
va_end(ap);
if (kmsg_fd < 0 || (n < 0 || ((unsigned) n + 1 > sizeof(message))))
return;
(void) write(kmsg_fd, message, n + 1);
}
static int lvm_uses_lvmetad(void)
{
lvm_t lvm;
int r;
if (!(lvm = lvm_init(NULL))) {
kmsg("LVM: Failed to initialize library context for activation generator.\n");
return 0;
}
r = lvm_config_find_bool(lvm, LVM_CONF_USE_LVMETAD, 0);
lvm_quit(lvm);
return r;
}
static int register_unit_with_target(const char *dir, const char *unit, const char *target)
{
int r = 1;
if (dm_snprintf(target_path, PATH_MAX, "%s/%s.wants", dir, target) < 0) {
r = 0; goto out;
}
(void) dm_prepare_selinux_context(target_path, S_IFDIR);
if (mkdir(target_path, 0755) < 0 && errno != EEXIST) {
kmsg("LVM: Failed to create target directory %s: %m.\n", target_path);
r = 0; goto out;
}
if (dm_snprintf(target_path, PATH_MAX, "%s/%s.wants/%s", dir, target, unit) < 0) {
r = 0; goto out;
}
(void) dm_prepare_selinux_context(target_path, S_IFLNK);
if (symlink(unit_path, target_path) < 0) {
kmsg("LVM: Failed to create symlink for unit %s: %m.\n", unit);
r = 0;
}
out:
dm_prepare_selinux_context(NULL, 0);
return r;
}
static int generate_unit(const char *dir, int early)
{
FILE *f;
const char *unit = early ? UNIT_NAME_EARLY : UNIT_NAME;
if (dm_snprintf(unit_path, PATH_MAX, "%s/%s", dir, unit) < 0)
return 0;
if (!(f = fopen(unit_path, "wxe"))) {
kmsg("LVM: Failed to create unit file %s: %m.\n", unit);
return 0;
}
fputs("# Automatically generated by lvm2-activation-generator.\n"
"#\n"
"# This unit is responsible for direct activation of LVM2 logical volumes\n"
"# if lvmetad daemon is not used (global/use_lvmetad=0 lvm.conf setting),\n"
"# hence volume autoactivation is not applicable.\n"
"# Direct LVM2 activation requires udev to be settled!\n\n"
"[Unit]\n"
"Description=Activation of LVM2 logical volumes\n"
"Documentation=man:lvm(8) man:vgchange(8)\n"
"SourcePath=/etc/lvm/lvm.conf\n"
"DefaultDependencies=no\n", f);
if (early) {
fputs("After=systemd-udev-settle.service\n", f);
fputs("Before=cryptsetup.target\n", f);
} else
fputs("After=lvm2-activation-early.service cryptsetup.target\n", f);
fputs("Before=local-fs.target shutdown.target\n"
"Wants=systemd-udev-settle.service\n\n"
"[Service]\n"
"ExecStart=/usr/sbin/lvm vgchange -aay --sysinit\n"
"Type=oneshot\n", f);
if (fclose(f) < 0) {
kmsg("LVM: Failed to write unit file %s: %m.\n", unit);
return 0;
}
if (!register_unit_with_target(dir, unit, UNIT_TARGET)) {
kmsg("LVM: Failed to register unit %s with target %s.\n", unit, UNIT_TARGET);
return 0;
}
return 1;
}
int main(int argc, char *argv[])
{
const char *dir;
int r = EXIT_SUCCESS;
kmsg_fd = open(KMSG_DEV_PATH, O_WRONLY|O_NOCTTY);
if (argc > 1 && argc != 4) {
kmsg("LVM: Activation generator takes three or no arguments.\n");
r = EXIT_FAILURE; goto out;
}
/* If lvmetad used, rely on autoactivation instead of direct activation. */
if (lvm_uses_lvmetad()) {
kmsg("LVM: Logical Volume autoactivation enabled.\n");
goto out;
}
dir = argc > 1 ? argv[1] : DEFAULT_UNIT_DIR;
if (!generate_unit(dir, 1) || !generate_unit(dir, 0))
r = EXIT_FAILURE;
out:
kmsg("LVM: Activation generator %s.\n", r ? "failed" : "successfully completed");
if (kmsg_fd != -1)
(void) close(kmsg_fd);
return r;
}