static int check_btrfs(void) {
struct statfs sfs;
if (statfs("/var/lib/machines", &sfs) < 0) {
if (errno != ENOENT)
return -errno;
if (statfs("/var/lib", &sfs) < 0)
return -errno;
}
return F_TYPE_EQUAL(sfs.f_type, BTRFS_SUPER_MAGIC);
}
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
* allow symlinking trees into /var/lib/machines/, and treat
* them normally. */
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, "a);
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
* 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),
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;
}
static int switchroot(const char *newroot)
{
/* Don't try to unmount the old "/", there's no way to do it. */
const char *umounts[] = { "/dev", "/proc", "/sys", "/run", NULL };
int i;
int cfd;
pid_t pid;
struct stat newroot_stat, sb;
if (stat(newroot, &newroot_stat) != 0) {
warn(_("stat failed %s"), newroot);
return -1;
}
for (i = 0; umounts[i] != NULL; i++) {
char newmount[PATH_MAX];
snprintf(newmount, sizeof(newmount), "%s%s", newroot, umounts[i]);
if ((stat(newmount, &sb) != 0) || (sb.st_dev != newroot_stat.st_dev)) {
/* mount point seems to be mounted already or stat failed */
umount2(umounts[i], MNT_DETACH);
continue;
}
if (mount(umounts[i], newmount, NULL, MS_MOVE, NULL) < 0) {
warn(_("failed to mount moving %s to %s"),
umounts[i], newmount);
warnx(_("forcing unmount of %s"), umounts[i]);
umount2(umounts[i], MNT_FORCE);
}
}
if (chdir(newroot)) {
warn(_("failed to change directory to %s"), newroot);
return -1;
}
cfd = open("/", O_RDONLY);
if (cfd < 0) {
warn(_("cannot open %s"), "/");
return -1;
}
if (mount(newroot, "/", NULL, MS_MOVE, NULL) < 0) {
close(cfd);
warn(_("failed to mount moving %s to /"), newroot);
return -1;
}
if (chroot(".")) {
close(cfd);
warn(_("failed to change root"));
return -1;
}
if (cfd >= 0) {
pid = fork();
if (pid <= 0) {
struct statfs stfs;
if (fstatfs(cfd, &stfs) == 0 &&
(F_TYPE_EQUAL(stfs.f_type, STATFS_RAMFS_MAGIC) ||
F_TYPE_EQUAL(stfs.f_type, STATFS_TMPFS_MAGIC)))
recursiveRemove(cfd);
else
warn(_("old root filesystem is not an initramfs"));
if (pid == 0)
exit(EXIT_SUCCESS);
}
close(cfd);
}
return 0;
}
bool is_fs_type(const struct statfs *s, statfs_f_type_t magic_value) {
assert(s);
assert_cc(sizeof(statfs_f_type_t) >= sizeof(s->f_type));
return F_TYPE_EQUAL(s->f_type, magic_value);
}
