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gpt-auto-generator: add basic auto-discovery of GPT partitions

Browse source 
This adds a simple generator that is capable of automatically
discovering certain GPT partitions by their type UUID and mount/enable
them. This currently covers swap partitions and /home partitions, but is
expected to grow more features soon.

This currently doesn't handle LUKS encrypted /home.

This enables all swap partitions of type
0657fd6da4ab43c484e50933c84b4f4f, if found.

This mounts the first partition of type 933ac7e12eb44f13b8440e14e2aef915
as /home, if it is found.
This commit is contained in:
Lennart Poettering 2013-08-13 10:13:45 +02:00
parent bed2e820db
commit 1a14a53cfd
4 changed files with 513 additions and 0 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

1
.gitignore vendored
View file

@ -46,6 +46,7 @@
/systemd-fstab-generator
/systemd-getty-generator
/systemd-gnome-ask-password-agent
/systemd-gpt-auto-generator
/systemd-hostnamed
/systemd-inhibit
/systemd-initctl

18
Makefile.am
View file

@ -1702,6 +1702,24 @@ bin_PROGRAMS += \
bootctl
endif
# ------------------------------------------------------------------------------
systemgenerator_PROGRAMS += \
systemd-gpt-auto-generator
systemd_gpt_auto_generator_SOURCES = \
src/gpt-auto-generator/gpt-auto-generator.c
systemd_gpt_auto_generator_LDADD = \
libsystemd-label.la \
libsystemd-shared.la \
libsystemd-id128-internal.la \
libudev-private.la \
$(BLKID_LIBS)
systemd_gpt_auto_generator_CFLAGS = \
$(AM_CFLAGS) \
$(BLKID_CFLAGS)
# ------------------------------------------------------------------------------
systemd_rc_local_generator_SOURCES = \
src/rc-local-generator/rc-local-generator.c

2
TODO
View file

@ -54,6 +54,8 @@ CGroup Rework Completion:
Features:
* rename F_TYPE_CMP() to F_TYPE_EQUAL()
* unlink PID files of units after exit
* tiny tool that saves/restores backlight

492
src/gpt-auto-generator/gpt-auto-generator.c Normal file
View file

@ -0,0 +1,492 @@
/*-*- 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 <linux/btrfs.h>
#include <sys/ioctl.h>
#include <sys/statfs.h>
#include <blkid.h>
#include "path-util.h"
#include "util.h"
#include "mkdir.h"
#include "missing.h"
#include "sd-id128.h"
#include "libudev.h"
#include "special.h"
#include "unit-name.h"
/* TODO:
*
* - Properly handle cryptsetup partitions
* - Define new partition type for encrypted swap
*
*/
static const char *arg_dest = "/tmp";
static int verify_gpt_partition(dev_t dev, sd_id128_t *type, unsigned *nr, char **fstype) {
_cleanup_free_ char *t = NULL;
blkid_probe b = NULL;
const char *v;
int r;
r = asprintf(&t, "/dev/block/%u:%u", major(dev), minor(dev));
if (r < 0)
return -ENOMEM;
errno = 0;
b = blkid_new_probe_from_filename(t);
if (!b) {
if (errno != 0)
return -errno;
return -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) {
r = -ENODEV;
goto finish;
} else if (r == 1) {
r = -ENODEV;
goto finish;
} else if (r != 0) {
r = errno ? -errno : -EIO;
goto finish;
}
errno = 0;
r = blkid_probe_lookup_value(b, "PART_ENTRY_SCHEME", &v, NULL);
if (r != 0) {
r = errno ? -errno : -EIO;
goto finish;
}
if (strcmp(v, "gpt") != 0) {
r = 0;
goto finish;
}
if (type) {
errno = 0;
r = blkid_probe_lookup_value(b, "PART_ENTRY_TYPE", &v, NULL);
if (r != 0) {
r = errno ? -errno : -EIO;
goto finish;
}
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) {
r = errno ? -errno : -EIO;
goto finish;
}
r = safe_atou(v, nr);
if (r < 0)
return r;
}
if (fstype) {
char *fst;
errno = 0;
r = blkid_probe_lookup_value(b, "TYPE", &v, NULL);
if (r != 0)
*fstype = NULL;
else {
fst = strdup(v);
if (!fst) {
r = -ENOMEM;
goto finish;
}
*fstype = fst;
}
}
return 1;
finish:
if (b)
blkid_free_probe(b);
return r;
}
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"
"[Mount]\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;
_cleanup_fclose_ FILE *f = NULL;
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;
}
fprintf(f,
"# Automatically generated by systemd-gpt-auto-generator\n\n"
"[Unit]\n"
"DefaultDependencies=no\n"
"After=" SPECIAL_LOCAL_FS_PRE_TARGET "\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"
"FsckPassNo=2\n",
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(dev_t dev) {
struct udev *udev;
struct udev_enumerate *e = NULL;
struct udev_device *parent = NULL, *d = NULL;
struct udev_list_entry *first, *item;
unsigned home_nr = (unsigned) -1;
_cleanup_free_ char *home = NULL, *home_fstype = NULL;
int r;
udev = udev_new();
if (!udev)
return log_oom();
e = udev_enumerate_new(udev);
if (!e) {
r = log_oom();
goto finish;
}
d = udev_device_new_from_devnum(udev, 'b', dev);
if (!d) {
r = log_oom();
goto finish;
}
parent = udev_device_get_parent(d);
if (!parent) {
r = log_oom();
goto finish;
}
r = udev_enumerate_add_match_parent(e, parent);
if (r < 0) {
r = log_oom();
goto finish;
}
r = udev_enumerate_add_match_subsystem(e, "block");
if (r < 0) {
r = log_oom();
goto finish;
}
r = udev_enumerate_scan_devices(e);
if (r < 0) {
log_error("Failed to enumerate partitions: %s", strerror(-r));
goto finish;
}
first = udev_enumerate_get_list_entry(e);
udev_list_entry_foreach(item, first) {
_cleanup_free_ char *fstype = NULL;
const char *node = NULL;
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) {
r = log_oom();
goto finish;
}
if (udev_device_get_devnum(q) == udev_device_get_devnum(d))
goto skip;
if (udev_device_get_devnum(q) == udev_device_get_devnum(parent))
goto skip;
node = udev_device_get_devnode(q);
if (!node) {
r = log_oom();
goto finish;
}
r = verify_gpt_partition(udev_device_get_devnum(q), &type_id, &nr, &fstype);
if (r < 0) {
log_error("Failed to verify GPT partition: %s", strerror(-r));
udev_device_unref(q);
goto finish;
}
if (r == 0)
goto skip;
if (sd_id128_equal(type_id, SD_ID128_MAKE(06,57,fd,6d,a4,ab,43,c4,84,e5,09,33,c8,4b,4f,4f)))
add_swap(node, fstype);
else if (sd_id128_equal(type_id, SD_ID128_MAKE(93,3a,c7,e1,2e,b4,4f,13,b8,44,0e,14,e2,ae,f9,15))) {
if (!home || nr < home_nr) {
free(home);
home = strdup(node);
if (!home) {
r = log_oom();
goto finish;
}
home_nr = nr;
free(home_fstype);
home_fstype = fstype;
fstype = NULL;
}
}
skip:
udev_device_unref(q);
}
if (home && home_fstype)
add_home(home, home_fstype);
finish:
if (d)
udev_device_unref(d);
if (e)
udev_enumerate_unref(e);
if (udev)
udev_unref(udev);
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;
zero(fsi);
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;
struct stat st;
zero(di);
di.devid = id;
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_CMP(sfs.f_type, BTRFS_SUPER_MAGIC))
return get_btrfs_block_device(path, dev);
return 0;
}
int main(int argc, char *argv[]) {
dev_t dev;
int r;
if (argc > 1 && argc != 4) {
log_error("This program takes three or no arguments.");
return EXIT_FAILURE;
}
if (argc > 1)
arg_dest = argv[3];
log_set_target(LOG_TARGET_SAFE);
log_parse_environment();
log_open();
umask(0022);
if (in_initrd())
return EXIT_SUCCESS;
r = get_block_device("/", &dev);
if (r < 0) {
log_error("Failed to determine block device of root file system: %s", strerror(-r));
return EXIT_FAILURE;
}
if (r == 0) {
log_debug("Root file system not on a (single) block device.");
return EXIT_SUCCESS;
}
log_debug("Root device %u:%u.", major(dev), minor(dev));
r = verify_gpt_partition(dev, NULL, NULL, NULL);
if (r < 0) {
log_error("Failed to verify GPT partition: %s", strerror(-r));
return EXIT_FAILURE;
}
if (r == 0)
return EXIT_SUCCESS;
r = enumerate_partitions(dev);
return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
}