#include <sys/statfs.h>

#include <linux/fs.h>

#include <fcntl.h>

#include "strv.h"

#include "utf8.h"

#include "btrfs-util.h"

#include "path-util.h"

#include "copy.h"

#include "mkdir.h"

#include "machine-image.h"

static const char image_search_path[] =

"/var/lib/machines\0"

"/var/lib/container\0"

"/usr/local/lib/machines\0"

"/usr/lib/machines\0";

Image *image_unref(Image *i) {

if (!i)

return NULL;

free(i->name);

free(i->path);

free(i);

return NULL;

}

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 = new0(Image, 1);

if (!i)

return -ENOMEM;

i->type = t;

i->read_only = read_only;

i->crtime = crtime;

i->mtime = mtime;

i->usage = i->usage_exclusive = (uint64_t) -1;

i->limit = i->limit_exclusive = (uint64_t) -1;

i->name = strdup(pretty);

if (!i->name)

return -ENOMEM;

if (path)

i->path = strjoin(path, "/", filename, NULL);

else

i->path = strdup(filename);

if (!i->path)

return -ENOMEM;

path_kill_slashes(i->path);

*ret = i;

i = NULL;

return 0;

}

static int image_make(

const char *pretty,

int dfd,

const char *path,

const char *filename,

Image **ret) {

struct stat st;

bool read_only;

int r;

assert(filename);

/* We explicitly *do* follow symlinks here, since we want to

if (fstatat(dfd, filename, &st, 0) < 0)

return -errno;

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;

if (!ret)

return 1;

if (!pretty)

pretty = filename;

fd = openat(dfd, filename, O_CLOEXEC|O_NOCTTY|O_DIRECTORY);

if (fd < 0)

return -errno;

/* btrfs subvolumes have inode 256 */

if (st.st_ino == 256) {

struct statfs sfs;

if (fstatfs(fd, &sfs) < 0)

return -errno;

if (F_TYPE_EQUAL(sfs.f_type, BTRFS_SUPER_MAGIC)) {

BtrfsSubvolInfo info;

BtrfsQuotaInfo quota;

/* It's a btrfs subvolume */

r = btrfs_subvol_get_info_fd(fd, &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;

r = btrfs_subvol_get_quota_fd(fd, &quota);

if (r >= 0) {

(*ret)->usage = quota.referred;

(*ret)->usage_exclusive = quota.exclusive;

(*ret)->limit = quota.referred_max;

(*ret)->limit_exclusive = quota.exclusive_max;

}

return 1;

}

}

/* If the IMMUTABLE bit is set, we consider the

(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),

0,

0,

ret);

if (r < 0)

return r;

return 1;

} else if (S_ISREG(st.st_mode) && endswith(filename, ".raw")) {

usec_t crtime = 0;

/* It's a RAW disk image */

if (!ret)

return 1;

fd_getcrtime_at(dfd, filename, &crtime, 0);

if (!pretty)

pretty = strndupa(filename, strlen(filename) - 4);

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 1;

}

return 0;

}

int image_find(const char *name, Image **ret) {

const char *path;

int r;

assert(name);

/* There are no images with invalid names */

if (!image_name_is_valid(name))

return 0;

NULSTR_FOREACH(path, image_search_path) {

_cleanup_closedir_ DIR *d = NULL;

d = opendir(path);

if (!d) {

if (errno == ENOENT)

continue;

return -errno;

}

r = image_make(NULL, dirfd(d), path, name, ret);

if (r == 0 || r == -ENOENT) {

_cleanup_free_ char *raw = NULL;

raw = strappend(name, ".raw");

if (!raw)

return -ENOMEM;

r = image_make(NULL, dirfd(d), path, raw, ret);

if (r == 0 || r == -ENOENT)

continue;

}

if (r < 0)

return r;

return 1;

}

if (streq(name, ".host"))

return image_make(".host", AT_FDCWD, NULL, "/", ret);

return 0;

};

int image_discover(Hashmap *h) {

const char *path;

int r;

assert(h);

NULSTR_FOREACH(path, image_search_path) {

_cleanup_closedir_ DIR *d = NULL;

struct dirent *de;

d = opendir(path);

if (!d) {

if (errno == ENOENT)

continue;

return -errno;

}

FOREACH_DIRENT_ALL(de, d, return -errno) {

_cleanup_(image_unrefp) Image *image = NULL;

if (!image_name_is_valid(de->d_name))

continue;

if (hashmap_contains(h, de->d_name))

continue;

r = image_make(NULL, dirfd(d), path, de->d_name, &image);

if (r == 0 || r == -ENOENT)

continue;

if (r < 0)

return r;

r = hashmap_put(h, image->name, image);

if (r < 0)

return r;

image = NULL;

}

}

if (!hashmap_contains(h, ".host")) {

_cleanup_(image_unrefp) Image *image = NULL;

r = image_make(".host", AT_FDCWD, NULL, "/", &image);

if (r < 0)

return r;

r = hashmap_put(h, image->name, image);

if (r < 0)

return r;

image = NULL;

}

return 0;

}

void image_hashmap_free(Hashmap *map) {

Image *i;

while ((i = hashmap_steal_first(map)))

image_unref(i);

hashmap_free(map);

}

int image_remove(Image *i) {

_cleanup_release_lock_file_ LockFile global_lock = LOCK_FILE_INIT, local_lock = LOCK_FILE_INIT;

int r;

assert(i);

if (path_equal(i->path, "/") ||

path_startswith(i->path, "/usr"))

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:

return btrfs_subvol_remove(i->path);

case IMAGE_DIRECTORY:

/* Allow deletion of read-only directories */

(void) chattr_path(i->path, false, FS_IMMUTABLE_FL);

/* fall through */

case IMAGE_RAW:

return rm_rf_dangerous(i->path, false, true, false);

default:

return -ENOTSUP;

}

}

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;

unsigned file_attr = 0;

int r;

assert(i);

if (!image_name_is_valid(new_name))

return -EINVAL;

if (path_equal(i->path, "/") ||

path_startswith(i->path, "/usr"))

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;

/* Make sure nobody takes the new name, between the time we

r = image_name_lock(new_name, LOCK_EX|LOCK_NB, &name_lock);

if (r < 0)

return r;

r = image_find(new_name, NULL);

if (r < 0)

return r;

if (r > 0)

return -EEXIST;

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, false, FS_IMMUTABLE_FL);

/* fall through */

case IMAGE_SUBVOLUME:

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 -ENOTSUP;

}

if (!new_path)

return -ENOMEM;

nn = strdup(new_name);

if (!nn)

return -ENOMEM;

if (renameat2(AT_FDCWD, i->path, AT_FDCWD, new_path, RENAME_NOREPLACE) < 0)

return -errno;

/* Restore the immutable bit, if it was set before */

if (file_attr & FS_IMMUTABLE_FL)

(void) chattr_path(new_path, true, FS_IMMUTABLE_FL);

free(i->path);

i->path = new_path;

new_path = NULL;

free(i->name);

i->name = nn;

nn = NULL;

return 0;

}

int image_clone(Image *i, const char *new_name, bool read_only) {

_cleanup_release_lock_file_ LockFile name_lock = LOCK_FILE_INIT;

const char *new_path;

int r;

assert(i);

if (!image_name_is_valid(new_name))

return -EINVAL;

/* Make sure nobody takes the new name, between the time we

r = image_name_lock(new_name, LOCK_EX|LOCK_NB, &name_lock);

if (r < 0)

return r;

r = image_find(new_name, NULL);

if (r < 0)

return r;

if (r > 0)

return -EEXIST;

switch (i->type) {

case IMAGE_SUBVOLUME:

case IMAGE_DIRECTORY:

new_path = strjoina("/var/lib/machines/", new_name);

r = btrfs_subvol_snapshot(i->path, new_path, read_only, 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, false, FS_NOCOW_FL);

break;

default:

return -ENOTSUP;

}

if (r < 0)

return r;

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 (path_equal(i->path, "/") ||

path_startswith(i->path, "/usr"))

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:

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

r = chattr_path(i->path, b, FS_IMMUTABLE_FL);

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

if (b)

(void) btrfs_defrag(i->path);

break;

}

default:

return -ENOTSUP;

}

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;

int r;

assert(path);

assert(global);

assert(local);

/* Locks an image path. This actually creates two locks: one

if (path_equal(path, "/"))

return -EBUSY;

if (!path_is_absolute(path))

return -EINVAL;

if (stat(path, &st) >= 0) {

if (asprintf(&p, "/run/systemd/nspawn/locks/inode-%lu:%lu", (unsigned long) st.st_dev, (unsigned long) st.st_ino) < 0)

return -ENOMEM;

}

r = make_lock_file_for(path, operation, &t);

if (r < 0)

return r;

if (p) {

mkdir_p("/run/systemd/nspawn/locks", 0600);

r = make_lock_file(p, operation, global);

if (r < 0) {

release_lock_file(&t);

return r;

}

}

*local = t;

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 (!image_name_is_valid(name))

return -EINVAL;

if (streq(name, ".host"))

return -EBUSY;

mkdir_p("/run/systemd/nspawn/locks", 0600);

p = strjoina("/run/systemd/nspawn/locks/name-", name);

return make_lock_file(p, operation, ret);

}

bool image_name_is_valid(const char *s) {

if (!filename_is_valid(s))

return false;

if (string_has_cc(s, NULL))

return false;

if (!utf8_is_valid(s))

return false;

/* Temporary files for atomically creating new files */

if (startswith(s, ".#"))

return false;

return true;

}

static const char* const image_type_table[_IMAGE_TYPE_MAX] = {

[IMAGE_DIRECTORY] = "directory",

[IMAGE_SUBVOLUME] = "subvolume",

[IMAGE_RAW] = "raw",

};

DEFINE_STRING_TABLE_LOOKUP(image_type, ImageType);