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systemd-stable/src/shared/discover-image.c
Kai Lueke e374439f4b Use original filename for extension name check 
The loading of an extension image from a symlink "NAME.raw" to
"NAME-VERSION.raw" failed because the release file name check worked
with the backing file of the loop device which already resolves the
symlink and thus the found name "NAME-VERSION" mismatched "NAME".
Pass the original filename and use it instead of the backing file
when available. This fixes the loading of "NAME.raw" extensions which
are a symlink to "NAME-VERSION.raw" as, e.g., may be the case when
systemd-sysupdate manages multiple versions.

Fixes https://github.com/systemd/systemd/issues/24293
2022-09-06 03:53:03 +09:00

1309 lines
44 KiB
C
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/* SPDX-License-Identifier: LGPL-2.1-or-later */
#include <errno.h>
#include <fcntl.h>
#include <linux/fs.h>
#include <linux/loop.h>
#include <linux/magic.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/file.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <unistd.h>
#include "alloc-util.h"
#include "btrfs-util.h"
#include "chase-symlinks.h"
#include "chattr-util.h"
#include "copy.h"
#include "dirent-util.h"
#include "discover-image.h"
#include "dissect-image.h"
#include "env-file.h"
#include "env-util.h"
#include "fd-util.h"
#include "fs-util.h"
#include "hashmap.h"
#include "hostname-setup.h"
#include "id128-util.h"
#include "lockfile-util.h"
#include "log.h"
#include "loop-util.h"
#include "macro.h"
#include "mkdir.h"
#include "nulstr-util.h"
#include "os-util.h"
#include "path-util.h"
#include "rm-rf.h"
#include "stat-util.h"
#include "string-table.h"
#include "string-util.h"
#include "strv.h"
#include "time-util.h"
#include "utf8.h"
#include "xattr-util.h"
static const char* const image_search_path[_IMAGE_CLASS_MAX] = {
[IMAGE_MACHINE] = "/etc/machines\0" /* only place symlinks here */
"/run/machines\0" /* and here too */
"/var/lib/machines\0" /* the main place for images */
"/var/lib/container\0" /* legacy */
"/usr/local/lib/machines\0"
"/usr/lib/machines\0",
[IMAGE_PORTABLE] = "/etc/portables\0" /* only place symlinks here */
"/run/portables\0" /* and here too */
"/var/lib/portables\0" /* the main place for images */
"/usr/local/lib/portables\0"
"/usr/lib/portables\0",
[IMAGE_EXTENSION] = "/etc/extensions\0" /* only place symlinks here */
"/run/extensions\0" /* and here too */
"/var/lib/extensions\0" /* the main place for images */
"/usr/local/lib/extensions\0"
"/usr/lib/extensions\0",
};
static Image *image_free(Image *i) {
assert(i);
free(i->name);
free(i->path);
free(i->hostname);
strv_free(i->machine_info);
strv_free(i->os_release);
strv_free(i->extension_release);
return mfree(i);
}
DEFINE_TRIVIAL_REF_UNREF_FUNC(Image, image, image_free);
DEFINE_HASH_OPS_WITH_VALUE_DESTRUCTOR(image_hash_ops, char, string_hash_func, string_compare_func,
Image, image_unref);
static char **image_settings_path(Image *image) {
_cleanup_strv_free_ char **l = NULL;
const char *fn;
unsigned i = 0;
assert(image);
l = new0(char*, 4);
if (!l)
return NULL;
fn = strjoina(image->name, ".nspawn");
FOREACH_STRING(s, "/etc/systemd/nspawn", "/run/systemd/nspawn") {
l[i] = path_join(s, fn);
if (!l[i])
return NULL;
i++;
}
l[i] = file_in_same_dir(image->path, fn);
if (!l[i])
return NULL;
return TAKE_PTR(l);
}
static char *image_roothash_path(Image *image) {
const char *fn;
assert(image);
fn = strjoina(image->name, ".roothash");
return file_in_same_dir(image->path, fn);
}
static int image_new(
ImageType t,
const char *pretty,
const char *path,
const char *filename,
bool read_only,
usec_t crtime,
usec_t mtime,
Image **ret) {
_cleanup_(image_unrefp) Image *i = NULL;
assert(t >= 0);
assert(t < _IMAGE_TYPE_MAX);
assert(pretty);
assert(filename);
assert(ret);
i = new(Image, 1);
if (!i)
return -ENOMEM;
*i = (Image) {
.n_ref = 1,
.type = t,
.read_only = read_only,
.crtime = crtime,
.mtime = mtime,
.usage = UINT64_MAX,
.usage_exclusive = UINT64_MAX,
.limit = UINT64_MAX,
.limit_exclusive = UINT64_MAX,
};
i->name = strdup(pretty);
if (!i->name)
return -ENOMEM;
i->path = path_join(path, filename);
if (!i->path)
return -ENOMEM;
path_simplify(i->path);
*ret = TAKE_PTR(i);
return 0;
}
static int extract_pretty(const char *path, const char *suffix, char **ret) {
_cleanup_free_ char *name = NULL;
const char *p;
size_t n;
assert(path);
assert(ret);
p = last_path_component(path);
n = strcspn(p, "/");
name = strndup(p, n);
if (!name)
return -ENOMEM;
if (suffix) {
char *e;
e = endswith(name, suffix);
if (!e)
return -EINVAL;
*e = 0;
}
if (!image_name_is_valid(name))
return -EINVAL;
*ret = TAKE_PTR(name);
return 0;
}
static int image_make(
const char *pretty,
int dfd,
const char *path,
const char *filename,
const struct stat *st,
Image **ret) {
_cleanup_free_ char *pretty_buffer = NULL, *parent = NULL;
struct stat stbuf;
bool read_only;
int r;
assert(dfd >= 0 || dfd == AT_FDCWD);
assert(path || dfd == AT_FDCWD);
assert(filename);
/* We explicitly *do* follow symlinks here, since we want to allow symlinking trees, raw files and block
* devices into /var/lib/machines/, and treat them normally.
*
* This function returns -ENOENT if we can't find the image after all, and -EMEDIUMTYPE if it's not a file we
* recognize. */
if (!st) {
if (fstatat(dfd, filename, &stbuf, 0) < 0)
return -errno;
st = &stbuf;
}
if (!path) {
if (dfd == AT_FDCWD)
(void) safe_getcwd(&parent);
else
(void) fd_get_path(dfd, &parent);
}
read_only =
(path && path_startswith(path, "/usr")) ||
(faccessat(dfd, filename, W_OK, AT_EACCESS) < 0 && errno == EROFS);
if (S_ISDIR(st->st_mode)) {
_cleanup_close_ int fd = -1;
unsigned file_attr = 0;
usec_t crtime = 0;
if (!ret)
return 0;
if (!pretty) {
r = extract_pretty(filename, NULL, &pretty_buffer);
if (r < 0)
return r;
pretty = pretty_buffer;
}
fd = openat(dfd, filename, O_CLOEXEC|O_NOCTTY|O_DIRECTORY);
if (fd < 0)
return -errno;
if (btrfs_might_be_subvol(st)) {
r = fd_is_fs_type(fd, BTRFS_SUPER_MAGIC);
if (r < 0)
return r;
if (r) {
BtrfsSubvolInfo info;
/* It's a btrfs subvolume */
r = btrfs_subvol_get_info_fd(fd, 0, &info);
if (r < 0)
return r;
r = image_new(IMAGE_SUBVOLUME,
pretty,
path,
filename,
info.read_only || read_only,
info.otime,
0,
ret);
if (r < 0)
return r;
if (btrfs_quota_scan_ongoing(fd) == 0) {
BtrfsQuotaInfo quota;
r = btrfs_subvol_get_subtree_quota_fd(fd, 0, &quota);
if (r >= 0) {
(*ret)->usage = quota.referenced;
(*ret)->usage_exclusive = quota.exclusive;
(*ret)->limit = quota.referenced_max;
(*ret)->limit_exclusive = quota.exclusive_max;
}
}
return 0;
}
}
/* Get directory creation time (not available everywhere, but that's OK */
(void) fd_getcrtime(fd, &crtime);
/* If the IMMUTABLE bit is set, we consider the directory read-only. Since the ioctl is not
* supported everywhere we ignore failures. */
(void) read_attr_fd(fd, &file_attr);
/* It's just a normal directory. */
r = image_new(IMAGE_DIRECTORY,
pretty,
path,
filename,
read_only || (file_attr & FS_IMMUTABLE_FL),
crtime,
0, /* we don't use mtime of stat() here, since it's not the time of last change of the tree, but only of the top-level dir */
ret);
if (r < 0)
return r;
return 0;
} else if (S_ISREG(st->st_mode) && endswith(filename, ".raw")) {
usec_t crtime = 0;
/* It's a RAW disk image */
if (!ret)
return 0;
(void) fd_getcrtime_at(dfd, filename, AT_SYMLINK_FOLLOW, &crtime);
if (!pretty) {
r = extract_pretty(filename, ".raw", &pretty_buffer);
if (r < 0)
return r;
pretty = pretty_buffer;
}
r = image_new(IMAGE_RAW,
pretty,
path,
filename,
!(st->st_mode & 0222) || read_only,
crtime,
timespec_load(&st->st_mtim),
ret);
if (r < 0)
return r;
(*ret)->usage = (*ret)->usage_exclusive = st->st_blocks * 512;
(*ret)->limit = (*ret)->limit_exclusive = st->st_size;
return 0;
} else if (S_ISBLK(st->st_mode)) {
_cleanup_close_ int block_fd = -1;
uint64_t size = UINT64_MAX;
/* A block device */
if (!ret)
return 0;
if (!pretty) {
r = extract_pretty(filename, NULL, &pretty_buffer);
if (r < 0)
return r;
pretty = pretty_buffer;
}
block_fd = openat(dfd, filename, O_RDONLY|O_NONBLOCK|O_CLOEXEC|O_NOCTTY);
if (block_fd < 0)
log_debug_errno(errno, "Failed to open block device %s/%s, ignoring: %m", path ?: strnull(parent), filename);
else {
/* Refresh stat data after opening the node */
if (fstat(block_fd, &stbuf) < 0)
return -errno;
st = &stbuf;
if (!S_ISBLK(st->st_mode)) /* Verify that what we opened is actually what we think it is */
return -ENOTTY;
if (!read_only) {
int state = 0;
if (ioctl(block_fd, BLKROGET, &state) < 0)
log_debug_errno(errno, "Failed to issue BLKROGET on device %s/%s, ignoring: %m", path ?: strnull(parent), filename);
else if (state)
read_only = true;
}
if (ioctl(block_fd, BLKGETSIZE64, &size) < 0)
log_debug_errno(errno, "Failed to issue BLKGETSIZE64 on device %s/%s, ignoring: %m", path ?: strnull(parent), filename);
block_fd = safe_close(block_fd);
}
r = image_new(IMAGE_BLOCK,
pretty,
path,
filename,
!(st->st_mode & 0222) || read_only,
0,
0,
ret);
if (r < 0)
return r;
if (!IN_SET(size, 0, UINT64_MAX))
(*ret)->usage = (*ret)->usage_exclusive = (*ret)->limit = (*ret)->limit_exclusive = size;
return 0;
}
return -EMEDIUMTYPE;
}
int image_find(ImageClass class,
const char *name,
const char *root,
Image **ret) {
const char *path;
int r;
assert(class >= 0);
assert(class < _IMAGE_CLASS_MAX);
assert(name);
/* There are no images with invalid names */
if (!image_name_is_valid(name))
return -ENOENT;
NULSTR_FOREACH(path, image_search_path[class]) {
_cleanup_free_ char *resolved = NULL;
_cleanup_closedir_ DIR *d = NULL;
struct stat st;
int flags;
r = chase_symlinks_and_opendir(path, root, CHASE_PREFIX_ROOT, &resolved, &d);
if (r == -ENOENT)
continue;
if (r < 0)
return r;
/* As mentioned above, we follow symlinks on this fstatat(), because we want to permit people
* to symlink block devices into the search path. (For now, we disable that when operating
* relative to some root directory.) */
flags = root ? AT_SYMLINK_NOFOLLOW : 0;
if (fstatat(dirfd(d), name, &st, flags) < 0) {
_cleanup_free_ char *raw = NULL;
if (errno != ENOENT)
return -errno;
raw = strjoin(name, ".raw");
if (!raw)
return -ENOMEM;
if (fstatat(dirfd(d), raw, &st, flags) < 0) {
if (errno == ENOENT)
continue;
return -errno;
}
if (!S_ISREG(st.st_mode))
continue;
r = image_make(name, dirfd(d), resolved, raw, &st, ret);
} else {
if (!S_ISDIR(st.st_mode) && !S_ISBLK(st.st_mode))
continue;
r = image_make(name, dirfd(d), resolved, name, &st, ret);
}
if (IN_SET(r, -ENOENT, -EMEDIUMTYPE))
continue;
if (r < 0)
return r;
if (ret)
(*ret)->discoverable = true;
return 1;
}
if (class == IMAGE_MACHINE && streq(name, ".host")) {
r = image_make(".host", AT_FDCWD, NULL, empty_to_root(root), NULL, ret);
if (r < 0)
return r;
if (ret)
(*ret)->discoverable = true;
return r;
}
return -ENOENT;
};
int image_from_path(const char *path, Image **ret) {
/* Note that we don't set the 'discoverable' field of the returned object, because we don't check here whether
* the image is in the image search path. And if it is we don't know if the path we used is actually not
* overridden by another, different image earlier in the search path */
if (path_equal(path, "/"))
return image_make(".host", AT_FDCWD, NULL, "/", NULL, ret);
return image_make(NULL, AT_FDCWD, NULL, path, NULL, ret);
}
int image_find_harder(ImageClass class, const char *name_or_path, const char *root, Image **ret) {
if (image_name_is_valid(name_or_path))
return image_find(class, name_or_path, root, ret);
return image_from_path(name_or_path, ret);
}
int image_discover(
ImageClass class,
const char *root,
Hashmap *h) {
const char *path;
int r;
assert(class >= 0);
assert(class < _IMAGE_CLASS_MAX);
assert(h);
NULSTR_FOREACH(path, image_search_path[class]) {
_cleanup_free_ char *resolved = NULL;
_cleanup_closedir_ DIR *d = NULL;
r = chase_symlinks_and_opendir(path, root, CHASE_PREFIX_ROOT, &resolved, &d);
if (r == -ENOENT)
continue;
if (r < 0)
return r;
FOREACH_DIRENT_ALL(de, d, return -errno) {
_cleanup_(image_unrefp) Image *image = NULL;
_cleanup_free_ char *truncated = NULL;
const char *pretty;
struct stat st;
int flags;
if (dot_or_dot_dot(de->d_name))
continue;
/* As mentioned above, we follow symlinks on this fstatat(), because we want to
* permit people to symlink block devices into the search path. */
flags = root ? AT_SYMLINK_NOFOLLOW : 0;
if (fstatat(dirfd(d), de->d_name, &st, flags) < 0) {
if (errno == ENOENT)
continue;
return -errno;
}
if (S_ISREG(st.st_mode)) {
const char *e;
e = endswith(de->d_name, ".raw");
if (!e)
continue;
truncated = strndup(de->d_name, e - de->d_name);
if (!truncated)
return -ENOMEM;
pretty = truncated;
} else if (S_ISDIR(st.st_mode) || S_ISBLK(st.st_mode))
pretty = de->d_name;
else
continue;
if (!image_name_is_valid(pretty))
continue;
if (hashmap_contains(h, pretty))
continue;
r = image_make(pretty, dirfd(d), resolved, de->d_name, &st, &image);
if (IN_SET(r, -ENOENT, -EMEDIUMTYPE))
continue;
if (r < 0)
return r;
image->discoverable = true;
r = hashmap_put(h, image->name, image);
if (r < 0)
return r;
image = NULL;
}
}
if (class == IMAGE_MACHINE && !hashmap_contains(h, ".host")) {
_cleanup_(image_unrefp) Image *image = NULL;
r = image_make(".host", AT_FDCWD, NULL, empty_to_root("/"), NULL, &image);
if (r < 0)
return r;
image->discoverable = true;
r = hashmap_put(h, image->name, image);
if (r < 0)
return r;
image = NULL;
}
return 0;
}
int image_remove(Image *i) {
_cleanup_(release_lock_file) LockFile global_lock = LOCK_FILE_INIT, local_lock = LOCK_FILE_INIT;
_cleanup_strv_free_ char **settings = NULL;
_cleanup_free_ char *roothash = NULL;
int r;
assert(i);
if (IMAGE_IS_VENDOR(i) || IMAGE_IS_HOST(i))
return -EROFS;
settings = image_settings_path(i);
if (!settings)
return -ENOMEM;
roothash = image_roothash_path(i);
if (!roothash)
return -ENOMEM;
/* Make sure we don't interfere with a running nspawn */
r = image_path_lock(i->path, LOCK_EX|LOCK_NB, &global_lock, &local_lock);
if (r < 0)
return r;
switch (i->type) {
case IMAGE_SUBVOLUME:
/* Let's unlink first, maybe it is a symlink? If that works we are happy. Otherwise, let's get out the
* big guns */
if (unlink(i->path) < 0) {
r = btrfs_subvol_remove(i->path, BTRFS_REMOVE_RECURSIVE|BTRFS_REMOVE_QUOTA);
if (r < 0)
return r;
}
break;
case IMAGE_DIRECTORY:
/* Allow deletion of read-only directories */
(void) chattr_path(i->path, 0, FS_IMMUTABLE_FL, NULL);
r = rm_rf(i->path, REMOVE_ROOT|REMOVE_PHYSICAL|REMOVE_SUBVOLUME);
if (r < 0)
return r;
break;
case IMAGE_BLOCK:
/* If this is inside of /dev, then it's a real block device, hence let's not touch the device node
* itself (but let's remove the stuff stored alongside it). If it's anywhere else, let's try to unlink
* the thing (it's most likely a symlink after all). */
if (path_startswith(i->path, "/dev"))
break;
_fallthrough_;
case IMAGE_RAW:
if (unlink(i->path) < 0)
return -errno;
break;
default:
return -EOPNOTSUPP;
}
STRV_FOREACH(j, settings)
if (unlink(*j) < 0 && errno != ENOENT)
log_debug_errno(errno, "Failed to unlink %s, ignoring: %m", *j);
if (unlink(roothash) < 0 && errno != ENOENT)
log_debug_errno(errno, "Failed to unlink %s, ignoring: %m", roothash);
return 0;
}
static int rename_auxiliary_file(const char *path, const char *new_name, const char *suffix) {
_cleanup_free_ char *rs = NULL;
const char *fn;
fn = strjoina(new_name, suffix);
rs = file_in_same_dir(path, fn);
if (!rs)
return -ENOMEM;
return rename_noreplace(AT_FDCWD, path, AT_FDCWD, rs);
}
int image_rename(Image *i, const char *new_name) {
_cleanup_(release_lock_file) LockFile global_lock = LOCK_FILE_INIT, local_lock = LOCK_FILE_INIT, name_lock = LOCK_FILE_INIT;
_cleanup_free_ char *new_path = NULL, *nn = NULL, *roothash = NULL;
_cleanup_strv_free_ char **settings = NULL;
unsigned file_attr = 0;
int r;
assert(i);
if (!image_name_is_valid(new_name))
return -EINVAL;
if (IMAGE_IS_VENDOR(i) || IMAGE_IS_HOST(i))
return -EROFS;
settings = image_settings_path(i);
if (!settings)
return -ENOMEM;
roothash = image_roothash_path(i);
if (!roothash)
return -ENOMEM;
/* Make sure we don't interfere with a running nspawn */
r = image_path_lock(i->path, LOCK_EX|LOCK_NB, &global_lock, &local_lock);
if (r < 0)
return r;
/* Make sure nobody takes the new name, between the time we
* checked it is currently unused in all search paths, and the
* time we take possession of it */
r = image_name_lock(new_name, LOCK_EX|LOCK_NB, &name_lock);
if (r < 0)
return r;
r = image_find(IMAGE_MACHINE, new_name, NULL, NULL);
if (r >= 0)
return -EEXIST;
if (r != -ENOENT)
return r;
switch (i->type) {
case IMAGE_DIRECTORY:
/* Turn of the immutable bit while we rename the image, so that we can rename it */
(void) read_attr_path(i->path, &file_attr);
if (file_attr & FS_IMMUTABLE_FL)
(void) chattr_path(i->path, 0, FS_IMMUTABLE_FL, NULL);
_fallthrough_;
case IMAGE_SUBVOLUME:
new_path = file_in_same_dir(i->path, new_name);
break;
case IMAGE_BLOCK:
/* Refuse renaming raw block devices in /dev, the names are picked by udev after all. */
if (path_startswith(i->path, "/dev"))
return -EROFS;
new_path = file_in_same_dir(i->path, new_name);
break;
case IMAGE_RAW: {
const char *fn;
fn = strjoina(new_name, ".raw");
new_path = file_in_same_dir(i->path, fn);
break;
}
default:
return -EOPNOTSUPP;
}
if (!new_path)
return -ENOMEM;
nn = strdup(new_name);
if (!nn)
return -ENOMEM;
r = rename_noreplace(AT_FDCWD, i->path, AT_FDCWD, new_path);
if (r < 0)
return r;
/* Restore the immutable bit, if it was set before */
if (file_attr & FS_IMMUTABLE_FL)
(void) chattr_path(new_path, FS_IMMUTABLE_FL, FS_IMMUTABLE_FL, NULL);
free_and_replace(i->path, new_path);
free_and_replace(i->name, nn);
STRV_FOREACH(j, settings) {
r = rename_auxiliary_file(*j, new_name, ".nspawn");
if (r < 0 && r != -ENOENT)
log_debug_errno(r, "Failed to rename settings file %s, ignoring: %m", *j);
}
r = rename_auxiliary_file(roothash, new_name, ".roothash");
if (r < 0 && r != -ENOENT)
log_debug_errno(r, "Failed to rename roothash file %s, ignoring: %m", roothash);
return 0;
}
static int clone_auxiliary_file(const char *path, const char *new_name, const char *suffix) {
_cleanup_free_ char *rs = NULL;
const char *fn;
fn = strjoina(new_name, suffix);
rs = file_in_same_dir(path, fn);
if (!rs)
return -ENOMEM;
return copy_file_atomic(path, rs, 0664, 0, 0, COPY_REFLINK);
}
int image_clone(Image *i, const char *new_name, bool read_only) {
_cleanup_(release_lock_file) LockFile name_lock = LOCK_FILE_INIT;
_cleanup_strv_free_ char **settings = NULL;
_cleanup_free_ char *roothash = NULL;
const char *new_path;
int r;
assert(i);
if (!image_name_is_valid(new_name))
return -EINVAL;
settings = image_settings_path(i);
if (!settings)
return -ENOMEM;
roothash = image_roothash_path(i);
if (!roothash)
return -ENOMEM;
/* Make sure nobody takes the new name, between the time we
* checked it is currently unused in all search paths, and the
* time we take possession of it */
r = image_name_lock(new_name, LOCK_EX|LOCK_NB, &name_lock);
if (r < 0)
return r;
r = image_find(IMAGE_MACHINE, new_name, NULL, NULL);
if (r >= 0)
return -EEXIST;
if (r != -ENOENT)
return r;
switch (i->type) {
case IMAGE_SUBVOLUME:
case IMAGE_DIRECTORY:
/* If we can we'll always try to create a new btrfs subvolume here, even if the source is a plain
* directory. */
new_path = strjoina("/var/lib/machines/", new_name);
r = btrfs_subvol_snapshot(i->path, new_path,
(read_only ? BTRFS_SNAPSHOT_READ_ONLY : 0) |
BTRFS_SNAPSHOT_FALLBACK_COPY |
BTRFS_SNAPSHOT_FALLBACK_DIRECTORY |
BTRFS_SNAPSHOT_FALLBACK_IMMUTABLE |
BTRFS_SNAPSHOT_RECURSIVE |
BTRFS_SNAPSHOT_QUOTA);
if (r >= 0)
/* Enable "subtree" quotas for the copy, if we didn't copy any quota from the source. */
(void) btrfs_subvol_auto_qgroup(new_path, 0, true);
break;
case IMAGE_RAW:
new_path = strjoina("/var/lib/machines/", new_name, ".raw");
r = copy_file_atomic(i->path, new_path, read_only ? 0444 : 0644, FS_NOCOW_FL, FS_NOCOW_FL, COPY_REFLINK|COPY_CRTIME);
break;
case IMAGE_BLOCK:
default:
return -EOPNOTSUPP;
}
if (r < 0)
return r;
STRV_FOREACH(j, settings) {
r = clone_auxiliary_file(*j, new_name, ".nspawn");
if (r < 0 && r != -ENOENT)
log_debug_errno(r, "Failed to clone settings %s, ignoring: %m", *j);
}
r = clone_auxiliary_file(roothash, new_name, ".roothash");
if (r < 0 && r != -ENOENT)
log_debug_errno(r, "Failed to clone root hash file %s, ignoring: %m", roothash);
return 0;
}
int image_read_only(Image *i, bool b) {
_cleanup_(release_lock_file) LockFile global_lock = LOCK_FILE_INIT, local_lock = LOCK_FILE_INIT;
int r;
assert(i);
if (IMAGE_IS_VENDOR(i) || IMAGE_IS_HOST(i))
return -EROFS;
/* Make sure we don't interfere with a running nspawn */
r = image_path_lock(i->path, LOCK_EX|LOCK_NB, &global_lock, &local_lock);
if (r < 0)
return r;
switch (i->type) {
case IMAGE_SUBVOLUME:
/* Note that we set the flag only on the top-level
* subvolume of the image. */
r = btrfs_subvol_set_read_only(i->path, b);
if (r < 0)
return r;
break;
case IMAGE_DIRECTORY:
/* For simple directory trees we cannot use the access
mode of the top-level directory, since it has an
effect on the container itself. However, we can
use the "immutable" flag, to at least make the
top-level directory read-only. It's not as good as
a read-only subvolume, but at least something, and
we can read the value back. */
r = chattr_path(i->path, b ? FS_IMMUTABLE_FL : 0, FS_IMMUTABLE_FL, NULL);
if (r < 0)
return r;
break;
case IMAGE_RAW: {
struct stat st;
if (stat(i->path, &st) < 0)
return -errno;
if (chmod(i->path, (st.st_mode & 0444) | (b ? 0000 : 0200)) < 0)
return -errno;
/* If the images is now read-only, it's a good time to
* defrag it, given that no write patterns will
* fragment it again. */
if (b)
(void) btrfs_defrag(i->path);
break;
}
case IMAGE_BLOCK: {
_cleanup_close_ int fd = -1;
struct stat st;
int state = b;
fd = open(i->path, O_CLOEXEC|O_RDONLY|O_NONBLOCK|O_NOCTTY);
if (fd < 0)
return -errno;
if (fstat(fd, &st) < 0)
return -errno;
if (!S_ISBLK(st.st_mode))
return -ENOTTY;
if (ioctl(fd, BLKROSET, &state) < 0)
return -errno;
break;
}
default:
return -EOPNOTSUPP;
}
return 0;
}
int image_path_lock(const char *path, int operation, LockFile *global, LockFile *local) {
_cleanup_free_ char *p = NULL;
LockFile t = LOCK_FILE_INIT;
struct stat st;
bool exclusive;
int r;
assert(path);
assert(global);
assert(local);
/* Locks an image path. This actually creates two locks: one "local" one, next to the image path
* itself, which might be shared via NFS. And another "global" one, in /run, that uses the
* device/inode number. This has the benefit that we can even lock a tree that is a mount point,
* correctly. */
if (!path_is_absolute(path))
return -EINVAL;
switch (operation & (LOCK_SH|LOCK_EX)) {
case LOCK_SH:
exclusive = false;
break;
case LOCK_EX:
exclusive = true;
break;
default:
return -EINVAL;
}
if (getenv_bool("SYSTEMD_NSPAWN_LOCK") == 0) {
*local = *global = (LockFile) LOCK_FILE_INIT;
return 0;
}
/* Prohibit taking exclusive locks on the host image. We can't allow this, since we ourselves are
* running off it after all, and we don't want any images to manipulate the host image. We make an
* exception for shared locks however: we allow those (and make them NOPs since there's no point in
* taking them if there can't be exclusive locks). Strictly speaking these are questionable as well,
* since it means changes made to the host might propagate to the container as they happen (and a
* shared lock kinda suggests that no changes happen at all while it is in place), but it's too
* useful not to allow read-only containers off the host root, hence let's support this, and trust
* the user to do the right thing with this. */
if (path_equal(path, "/")) {
if (exclusive)
return -EBUSY;
*local = *global = (LockFile) LOCK_FILE_INIT;
return 0;
}
if (stat(path, &st) >= 0) {
if (S_ISBLK(st.st_mode))
r = asprintf(&p, "/run/systemd/nspawn/locks/block-%u:%u", major(st.st_rdev), minor(st.st_rdev));
else if (S_ISDIR(st.st_mode) || S_ISREG(st.st_mode))
r = asprintf(&p, "/run/systemd/nspawn/locks/inode-%lu:%lu", (unsigned long) st.st_dev, (unsigned long) st.st_ino);
else
return -ENOTTY;
if (r < 0)
return -ENOMEM;
}
/* For block devices we don't need the "local" lock, as the major/minor lock above should be
* sufficient, since block devices are host local anyway. */
if (!path_startswith(path, "/dev/")) {
r = make_lock_file_for(path, operation, &t);
if (r < 0) {
if (!exclusive && r == -EROFS)
log_debug_errno(r, "Failed to create shared lock for '%s', ignoring: %m", path);
else
return r;
}
}
if (p) {
(void) mkdir_p("/run/systemd/nspawn/locks", 0700);
r = make_lock_file(p, operation, global);
if (r < 0) {
release_lock_file(&t);
return r;
}
} else
*global = (LockFile) LOCK_FILE_INIT;
*local = t;
return 0;
}
int image_set_limit(Image *i, uint64_t referenced_max) {
assert(i);
if (IMAGE_IS_VENDOR(i) || IMAGE_IS_HOST(i))
return -EROFS;
if (i->type != IMAGE_SUBVOLUME)
return -EOPNOTSUPP;
/* We set the quota both for the subvolume as well as for the
* subtree. The latter is mostly for historical reasons, since
* we didn't use to have a concept of subtree quota, and hence
* only modified the subvolume quota. */
(void) btrfs_qgroup_set_limit(i->path, 0, referenced_max);
(void) btrfs_subvol_auto_qgroup(i->path, 0, true);
return btrfs_subvol_set_subtree_quota_limit(i->path, 0, referenced_max);
}
int image_read_metadata(Image *i) {
_cleanup_(release_lock_file) LockFile global_lock = LOCK_FILE_INIT, local_lock = LOCK_FILE_INIT;
int r;
assert(i);
r = image_path_lock(i->path, LOCK_SH|LOCK_NB, &global_lock, &local_lock);
if (r < 0)
return r;
switch (i->type) {
case IMAGE_SUBVOLUME:
case IMAGE_DIRECTORY: {
_cleanup_strv_free_ char **machine_info = NULL, **os_release = NULL, **extension_release = NULL;
sd_id128_t machine_id = SD_ID128_NULL;
_cleanup_free_ char *hostname = NULL;
_cleanup_free_ char *path = NULL;
r = chase_symlinks("/etc/hostname", i->path, CHASE_PREFIX_ROOT|CHASE_TRAIL_SLASH, &path, NULL);
if (r < 0 && r != -ENOENT)
log_debug_errno(r, "Failed to chase /etc/hostname in image %s: %m", i->name);
else if (r >= 0) {
r = read_etc_hostname(path, &hostname);
if (r < 0)
log_debug_errno(errno, "Failed to read /etc/hostname of image %s: %m", i->name);
}
path = mfree(path);
r = chase_symlinks("/etc/machine-id", i->path, CHASE_PREFIX_ROOT|CHASE_TRAIL_SLASH, &path, NULL);
if (r < 0 && r != -ENOENT)
log_debug_errno(r, "Failed to chase /etc/machine-id in image %s: %m", i->name);
else if (r >= 0) {
_cleanup_close_ int fd = -1;
fd = open(path, O_RDONLY|O_CLOEXEC|O_NOCTTY);
if (fd < 0)
log_debug_errno(errno, "Failed to open %s: %m", path);
else {
r = id128_read_fd(fd, ID128_PLAIN, &machine_id);
if (r < 0)
log_debug_errno(r, "Image %s contains invalid machine ID.", i->name);
}
}
path = mfree(path);
r = chase_symlinks("/etc/machine-info", i->path, CHASE_PREFIX_ROOT|CHASE_TRAIL_SLASH, &path, NULL);
if (r < 0 && r != -ENOENT)
log_debug_errno(r, "Failed to chase /etc/machine-info in image %s: %m", i->name);
else if (r >= 0) {
r = load_env_file_pairs(NULL, path, &machine_info);
if (r < 0)
log_debug_errno(r, "Failed to parse machine-info data of %s: %m", i->name);
}
r = load_os_release_pairs(i->path, &os_release);
if (r < 0)
log_debug_errno(r, "Failed to read os-release in image, ignoring: %m");
r = load_extension_release_pairs(i->path, i->name, &extension_release);
if (r < 0)
log_debug_errno(r, "Failed to read extension-release in image, ignoring: %m");
free_and_replace(i->hostname, hostname);
i->machine_id = machine_id;
strv_free_and_replace(i->machine_info, machine_info);
strv_free_and_replace(i->os_release, os_release);
strv_free_and_replace(i->extension_release, extension_release);
break;
}
case IMAGE_RAW:
case IMAGE_BLOCK: {
_cleanup_(loop_device_unrefp) LoopDevice *d = NULL;
_cleanup_(dissected_image_unrefp) DissectedImage *m = NULL;
r = loop_device_make_by_path(i->path, O_RDONLY, LO_FLAGS_PARTSCAN, LOCK_SH, &d);
if (r < 0)
return r;
r = dissect_loop_device(
d,
i->path,
NULL, NULL,
DISSECT_IMAGE_GENERIC_ROOT |
DISSECT_IMAGE_REQUIRE_ROOT |
DISSECT_IMAGE_RELAX_VAR_CHECK |
DISSECT_IMAGE_READ_ONLY |
DISSECT_IMAGE_USR_NO_ROOT,
&m);
if (r < 0)
return r;
r = dissected_image_acquire_metadata(m,
DISSECT_IMAGE_VALIDATE_OS |
DISSECT_IMAGE_VALIDATE_OS_EXT);
if (r < 0)
return r;
free_and_replace(i->hostname, m->hostname);
i->machine_id = m->machine_id;
strv_free_and_replace(i->machine_info, m->machine_info);
strv_free_and_replace(i->os_release, m->os_release);
strv_free_and_replace(i->extension_release, m->extension_release);
break;
}
default:
return -EOPNOTSUPP;
}
i->metadata_valid = true;
return 0;
}
int image_name_lock(const char *name, int operation, LockFile *ret) {
const char *p;
assert(name);
assert(ret);
/* Locks an image name, regardless of the precise path used. */
if (streq(name, ".host"))
return -EBUSY;
if (!image_name_is_valid(name))
return -EINVAL;
if (getenv_bool("SYSTEMD_NSPAWN_LOCK") == 0) {
*ret = (LockFile) LOCK_FILE_INIT;
return 0;
}
(void) mkdir_p("/run/systemd/nspawn/locks", 0700);
p = strjoina("/run/systemd/nspawn/locks/name-", name);
return make_lock_file(p, operation, ret);
}
bool image_in_search_path(
ImageClass class,
const char *root,
const char *image) {
const char *path;
assert(image);
NULSTR_FOREACH(path, image_search_path[class]) {
const char *p, *q;
size_t k;
if (!empty_or_root(root)) {
q = path_startswith(path, root);
if (!q)
continue;
} else
q = path;
p = path_startswith(q, path);
if (!p)
continue;
/* Make sure there's a filename following */
k = strcspn(p, "/");
if (k == 0)
continue;
p += k;
/* Accept trailing slashes */
if (p[strspn(p, "/")] == 0)
return true;
}
return false;
}
static const char* const image_type_table[_IMAGE_TYPE_MAX] = {
[IMAGE_DIRECTORY] = "directory",
[IMAGE_SUBVOLUME] = "subvolume",
[IMAGE_RAW] = "raw",
[IMAGE_BLOCK] = "block",
};
DEFINE_STRING_TABLE_LOOKUP(image_type, ImageType);
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