gpt-auto-generator.c revision 96115cdfe0241ae9b4e7177cd3874c0a93d00b39
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
/***
This file is part of systemd.
Copyright 2013 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <unistd.h>
#include <stdlib.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <sys/statfs.h>
#include <blkid/blkid.h>
#ifdef HAVE_LINUX_BTRFS_H
#include <linux/btrfs.h>
#endif
#include "path-util.h"
#include "util.h"
#include "mkdir.h"
#include "missing.h"
#include "sd-id128.h"
#include "libudev.h"
#include "udev-util.h"
#include "special.h"
#include "unit-name.h"
#include "virt.h"
/* TODO:
*
* - Properly handle cryptsetup partitions
* - Define new partition type for encrypted swap
* - Make /home automount rather than mount
*
*/
#define GPT_SWAP SD_ID128_MAKE(06,57,fd,6d,a4,ab,43,c4,84,e5,09,33,c8,4b,4f,4f)
#define GPT_HOME SD_ID128_MAKE(93,3a,c7,e1,2e,b4,4f,13,b8,44,0e,14,e2,ae,f9,15)
static const char *arg_dest = "/tmp";
DEFINE_TRIVIAL_CLEANUP_FUNC(blkid_probe, blkid_free_probe);
#define _cleanup_blkid_freep_probe_ _cleanup_(blkid_free_probep)
static int verify_gpt_partition(const char *node, sd_id128_t *type, unsigned *nr, char **fstype) {
_cleanup_blkid_freep_probe_ blkid_probe b = NULL;
const char *v;
int r;
errno = 0;
b = blkid_new_probe_from_filename(node);
if (!b)
return errno != 0 ? -errno : -ENOMEM;
blkid_probe_enable_superblocks(b, 1);
blkid_probe_set_superblocks_flags(b, BLKID_SUBLKS_TYPE);
blkid_probe_enable_partitions(b, 1);
blkid_probe_set_partitions_flags(b, BLKID_PARTS_ENTRY_DETAILS);
errno = 0;
r = blkid_do_safeprobe(b);
if (r == -2)
return -ENODEV;
else if (r == 1)
return -ENODEV;
else if (r != 0)
return errno ? -errno : -EIO;
errno = 0;
r = blkid_probe_lookup_value(b, "PART_ENTRY_SCHEME", &v, NULL);
if (r != 0)
/* return 0 if we're not on GPT */
return errno ? -errno : 0;
if (strcmp(v, "gpt") != 0)
return 0;
if (type) {
errno = 0;
r = blkid_probe_lookup_value(b, "PART_ENTRY_TYPE", &v, NULL);
if (r != 0)
return errno ? -errno : -EIO;
r = sd_id128_from_string(v, type);
if (r < 0)
return r;
}
if (nr) {
errno = 0;
r = blkid_probe_lookup_value(b, "PART_ENTRY_NUMBER", &v, NULL);
if (r != 0)
return errno ? -errno : -EIO;
r = safe_atou(v, nr);
if (r < 0)
return r;
}
if (fstype) {
errno = 0;
r = blkid_probe_lookup_value(b, "TYPE", &v, NULL);
if (r != 0)
*fstype = NULL;
else {
char *fst;
fst = strdup(v);
if (!fst)
return -ENOMEM;
*fstype = fst;
}
}
return 1;
}
static int add_swap(const char *path, const char *fstype) {
_cleanup_free_ char *name = NULL, *unit = NULL, *lnk = NULL;
_cleanup_fclose_ FILE *f = NULL;
log_debug("Adding swap: %s %s", path, fstype);
name = unit_name_from_path(path, ".swap");
if (!name)
return log_oom();
unit = strjoin(arg_dest, "/", name, NULL);
if (!unit)
return log_oom();
f = fopen(unit, "wxe");
if (!f) {
log_error("Failed to create unit file %s: %m", unit);
return -errno;
}
fprintf(f,
"# Automatically generated by systemd-gpt-auto-generator\n\n"
"[Unit]\n"
"DefaultDependencies=no\n"
"Conflicts=" SPECIAL_UMOUNT_TARGET "\n"
"Before=" SPECIAL_UMOUNT_TARGET " " SPECIAL_SWAP_TARGET "\n\n"
"[Swap]\n"
"What=%s\n",
path);
fflush(f);
if (ferror(f)) {
log_error("Failed to write unit file %s: %m", unit);
return -errno;
}
lnk = strjoin(arg_dest, "/" SPECIAL_SWAP_TARGET ".wants/", name, NULL);
if (!lnk)
return log_oom();
mkdir_parents_label(lnk, 0755);
if (symlink(unit, lnk) < 0) {
log_error("Failed to create symlink %s: %m", lnk);
return -errno;
}
return 0;
}
static int add_home(const char *path, const char *fstype) {
_cleanup_free_ char *unit = NULL, *lnk = NULL, *fsck = NULL;
_cleanup_fclose_ FILE *f = NULL;
if (dir_is_empty("/home") <= 0)
return 0;
log_debug("Adding home: %s %s", path, fstype);
unit = strappend(arg_dest, "/home.mount");
if (!unit)
return log_oom();
f = fopen(unit, "wxe");
if (!f) {
log_error("Failed to create unit file %s: %m", unit);
return -errno;
}
fsck = unit_name_from_path_instance("systemd-fsck", path, ".service");
if (!fsck)
return log_oom();
fprintf(f,
"# Automatically generated by systemd-gpt-auto-generator\n\n"
"[Unit]\n"
"DefaultDependencies=no\n"
"Requires=%s\n"
"After=" SPECIAL_LOCAL_FS_PRE_TARGET " %s\n"
"Conflicts=" SPECIAL_UMOUNT_TARGET "\n"
"Before=" SPECIAL_UMOUNT_TARGET " " SPECIAL_LOCAL_FS_TARGET "\n\n"
"[Mount]\n"
"What=%s\n"
"Where=/home\n"
"Type=%s\n",
fsck, fsck, path, fstype);
fflush(f);
if (ferror(f)) {
log_error("Failed to write unit file %s: %m", unit);
return -errno;
}
lnk = strjoin(arg_dest, "/" SPECIAL_LOCAL_FS_TARGET ".requires/home.mount", NULL);
if (!lnk)
return log_oom();
mkdir_parents_label(lnk, 0755);
if (symlink(unit, lnk) < 0) {
log_error("Failed to create symlink %s: %m", lnk);
return -errno;
}
return 0;
}
static int enumerate_partitions(struct udev *udev, dev_t dev) {
struct udev_device *parent = NULL;
_cleanup_udev_enumerate_unref_ struct udev_enumerate *e = NULL;
_cleanup_udev_device_unref_ struct udev_device *d = NULL;
struct udev_list_entry *first, *item;
unsigned home_nr = (unsigned) -1;
_cleanup_free_ char *home = NULL, *home_fstype = NULL;
int r;
e = udev_enumerate_new(udev);
if (!e)
return log_oom();
d = udev_device_new_from_devnum(udev, 'b', dev);
if (!d)
return log_oom();
parent = udev_device_get_parent(d);
if (!parent)
return log_oom();
r = udev_enumerate_add_match_parent(e, parent);
if (r < 0)
return log_oom();
r = udev_enumerate_add_match_subsystem(e, "block");
if (r < 0)
return log_oom();
r = udev_enumerate_scan_devices(e);
if (r < 0) {
log_error("Failed to enumerate partitions on /dev/block/%u:%u: %s",
major(dev), minor(dev), strerror(-r));
return r;
}
first = udev_enumerate_get_list_entry(e);
udev_list_entry_foreach(item, first) {
_cleanup_free_ char *fstype = NULL;
const char *node = NULL;
_cleanup_udev_device_unref_ struct udev_device *q;
sd_id128_t type_id;
unsigned nr;
q = udev_device_new_from_syspath(udev, udev_list_entry_get_name(item));
if (!q)
return log_oom();
if (udev_device_get_devnum(q) == udev_device_get_devnum(d))
continue;
if (udev_device_get_devnum(q) == udev_device_get_devnum(parent))
continue;
node = udev_device_get_devnode(q);
if (!node)
return log_oom();
r = verify_gpt_partition(node, &type_id, &nr, &fstype);
if (r < 0) {
log_error("Failed to verify GPT partition %s: %s",
node, strerror(-r));
return r;
}
if (r == 0)
continue;
if (sd_id128_equal(type_id, GPT_SWAP))
add_swap(node, fstype);
else if (sd_id128_equal(type_id, GPT_HOME)) {
if (!home || nr < home_nr) {
free(home);
home = strdup(node);
if (!home)
return log_oom();
home_nr = nr;
free(home_fstype);
home_fstype = fstype;
fstype = NULL;
}
}
}
if (home && home_fstype)
add_home(home, home_fstype);
return r;
}
static int get_btrfs_block_device(const char *path, dev_t *dev) {
struct btrfs_ioctl_fs_info_args fsi = {};
_cleanup_close_ int fd = -1;
uint64_t id;
assert(path);
assert(dev);
fd = open(path, O_DIRECTORY|O_CLOEXEC);
if (fd < 0)
return -errno;
if (ioctl(fd, BTRFS_IOC_FS_INFO, &fsi) < 0)
return -errno;
/* We won't do this for btrfs RAID */
if (fsi.num_devices != 1)
return 0;
for (id = 1; id <= fsi.max_id; id++) {
struct btrfs_ioctl_dev_info_args di = {
.devid = id,
};
struct stat st;
if (ioctl(fd, BTRFS_IOC_DEV_INFO, &di) < 0) {
if (errno == ENODEV)
continue;
return -errno;
}
if (stat((char*) di.path, &st) < 0)
return -errno;
if (!S_ISBLK(st.st_mode))
return -ENODEV;
if (major(st.st_rdev) == 0)
return -ENODEV;
*dev = st.st_rdev;
return 1;
}
return -ENODEV;
}
static int get_block_device(const char *path, dev_t *dev) {
struct stat st;
struct statfs sfs;
assert(path);
assert(dev);
if (lstat("/", &st))
return -errno;
if (major(st.st_dev) != 0) {
*dev = st.st_dev;
return 1;
}
if (statfs("/", &sfs) < 0)
return -errno;
if (F_TYPE_EQUAL(sfs.f_type, BTRFS_SUPER_MAGIC))
return get_btrfs_block_device(path, dev);
return 0;
}
static int devno_to_devnode(struct udev *udev, dev_t devno, char **ret) {
_cleanup_udev_device_unref_ struct udev_device *d;
const char *t;
char *n;
d = udev_device_new_from_devnum(udev, 'b', devno);
if (!d)
return log_oom();
t = udev_device_get_devnode(d);
if (!t)
return -ENODEV;
n = strdup(t);
if (!n)
return -ENOMEM;
*ret = n;
return 0;
}
int main(int argc, char *argv[]) {
_cleanup_free_ char *node = NULL;
_cleanup_udev_unref_ struct udev *udev = NULL;
dev_t devno;
int r = 0;
if (argc > 1 && argc != 4) {
log_error("This program takes three or no arguments.");
r = -EINVAL;
goto finish;
}
if (argc > 1)
arg_dest = argv[3];
log_set_target(LOG_TARGET_SAFE);
log_parse_environment();
log_open();
umask(0022);
if (in_initrd()) {
log_debug("In initrd, exiting.");
goto finish;
}
if (detect_container(NULL) > 0) {
log_debug("In a container, exiting.");
goto finish;
}
r = get_block_device("/", &devno);
if (r < 0) {
log_error("Failed to determine block device of root file system: %s", strerror(-r));
goto finish;
}
if (r == 0) {
log_debug("Root file system not on a (single) block device.");
goto finish;
}
udev = udev_new();
if (!udev) {
r = log_oom();
goto finish;
}
r = devno_to_devnode(udev, devno, &node);
if (r < 0) {
log_error("Failed to determine block device node from major/minor: %s", strerror(-r));
goto finish;
}
log_debug("Root device %s.", node);
r = verify_gpt_partition(node, NULL, NULL, NULL);
if (r < 0) {
log_error("Failed to verify GPT partition %s: %s", node, strerror(-r));
goto finish;
}
if (r == 0)
goto finish;
r = enumerate_partitions(udev, devno);
finish:
return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
}