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-rw-r--r--src/libshared/machine-image.c813
1 files changed, 813 insertions, 0 deletions
diff --git a/src/libshared/machine-image.c b/src/libshared/machine-image.c
new file mode 100644
index 0000000000..ed8a29c575
--- /dev/null
+++ b/src/libshared/machine-image.c
@@ -0,0 +1,813 @@
+/***
+ 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 <dirent.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <linux/fs.h>
+#include "alloc-util.h"
+#include "btrfs-util.h"
+#include "chattr-util.h"
+#include "copy.h"
+#include "dirent-util.h"
+#include "fd-util.h"
+#include "fs-util.h"
+#include "hashmap.h"
+#include "lockfile-util.h"
+#include "log.h"
+#include "macro.h"
+#include "machine-image.h"
+#include "mkdir.h"
+#include "path-util.h"
+#include "rm-rf.h"
+#include "string-table.h"
+#include "string-util.h"
+#include "strv.h"
+#include "time-util.h"
+#include "utf8.h"
+#include "util.h"
+#include "xattr-util.h"
+
+static const char image_search_path[] =
+ "/var/lib/machines\0"
+ "/var/lib/container\0" /* legacy */
+ "/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 char **image_settings_path(Image *image) {
+ _cleanup_strv_free_ char **l = NULL;
+ char **ret;
+ const char *fn, *s;
+ 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] = strappend(s, fn);
+ if (!l[i])
+ return NULL;
+
+ i++;
+ }
+
+ l[i] = file_in_same_dir(image->path, fn);
+ if (!l[i])
+ return NULL;
+
+ ret = l;
+ l = NULL;
+
+ return ret;
+}
+
+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
+ * 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) {
+
+ r = btrfs_is_filesystem(fd);
+ 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 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;
+}
+
+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;
+ _cleanup_strv_free_ char **settings = NULL;
+ char **j;
+ int r;
+
+ assert(i);
+
+ if (path_equal(i->path, "/") ||
+ path_startswith(i->path, "/usr"))
+ return -EROFS;
+
+ settings = image_settings_path(i);
+ if (!settings)
+ 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:
+ 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, false, FS_IMMUTABLE_FL);
+ r = rm_rf(i->path, REMOVE_ROOT|REMOVE_PHYSICAL|REMOVE_SUBVOLUME);
+ if (r < 0)
+ return r;
+
+ break;
+
+ 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);
+ }
+
+ return 0;
+}
+
+static int rename_settings_file(const char *path, const char *new_name) {
+ _cleanup_free_ char *rs = NULL;
+ const char *fn;
+
+ fn = strjoina(new_name, ".nspawn");
+
+ 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;
+ _cleanup_strv_free_ char **settings = NULL;
+ unsigned file_attr = 0;
+ char **j;
+ 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;
+
+ settings = image_settings_path(i);
+ if (!settings)
+ 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 possesion of it */
+ 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 -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, true, FS_IMMUTABLE_FL);
+
+ free(i->path);
+ i->path = new_path;
+ new_path = NULL;
+
+ free(i->name);
+ i->name = nn;
+ nn = NULL;
+
+ STRV_FOREACH(j, settings) {
+ r = rename_settings_file(*j, new_name);
+ if (r < 0 && r != -ENOENT)
+ log_debug_errno(r, "Failed to rename settings file %s, ignoring: %m", *j);
+ }
+
+ return 0;
+}
+
+static int clone_settings_file(const char *path, const char *new_name) {
+ _cleanup_free_ char *rs = NULL;
+ const char *fn;
+
+ fn = strjoina(new_name, ".nspawn");
+
+ rs = file_in_same_dir(path, fn);
+ if (!rs)
+ return -ENOMEM;
+
+ return copy_file_atomic(path, rs, 0664, false, 0);
+}
+
+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;
+ const char *new_path;
+ char **j;
+ int r;
+
+ assert(i);
+
+ if (!image_name_is_valid(new_name))
+ return -EINVAL;
+
+ settings = image_settings_path(i);
+ if (!settings)
+ 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 possesion of it */
+ 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 ? BTRFS_SNAPSHOT_READ_ONLY : 0) | BTRFS_SNAPSHOT_FALLBACK_COPY | BTRFS_SNAPSHOT_RECURSIVE | BTRFS_SNAPSHOT_QUOTA);
+
+ /* Enable "subtree" quotas for the copy, if we didn't
+ * copy any quota from the source. */
+ (void) btrfs_subvol_auto_qgroup(i->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, false, FS_NOCOW_FL);
+ break;
+
+ default:
+ return -EOPNOTSUPP;
+ }
+
+ if (r < 0)
+ return r;
+
+ STRV_FOREACH(j, settings) {
+ r = clone_settings_file(*j, new_name);
+ if (r < 0 && r != -ENOENT)
+ log_debug_errno(r, "Failed to clone settings %s, ignoring: %m", *j);
+ }
+
+ 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:
+
+ /* 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);
+ 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;
+ }
+
+ 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;
+ 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_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", 0700);
+
+ r = make_lock_file(p, operation, global);
+ if (r < 0) {
+ release_lock_file(&t);
+ return r;
+ }
+ }
+
+ *local = t;
+ return 0;
+}
+
+int image_set_limit(Image *i, uint64_t referenced_max) {
+ assert(i);
+
+ if (path_equal(i->path, "/") ||
+ path_startswith(i->path, "/usr"))
+ 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_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", 0700);
+ 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);
generated by cgit v1.2.3-54-g00ecf (git 2.45.2) at 2024-11-01 03:47:59 +0000