machined: Move image discovery logic into src/shared, so that we can make use of it from nspawn
This commit is contained in:
Lennart Poettering
@@ -0,0 +1,325 @@
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/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
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/***
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This file is part of systemd.
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Copyright 2013 Lennart Poettering
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systemd is free software; you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version.
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systemd is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with systemd; If not, see <http://www.gnu.org/licenses/>.
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***/
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#include <sys/statfs.h>
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#include "strv.h"
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#include "utf8.h"
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#include "btrfs-util.h"
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#include "path-util.h"
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#include "machine-image.h"
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static const char image_search_path[] =
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"/var/lib/machines\0"
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"/var/lib/container\0"
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"/usr/local/lib/machines\0"
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"/usr/lib/machines\0";
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Image *image_unref(Image *i) {
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if (!i)
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return NULL;
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free(i->name);
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free(i->path);
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free(i);
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return NULL;
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}
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static int image_new(
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ImageType t,
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const char *pretty,
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const char *path,
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const char *filename,
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bool read_only,
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usec_t crtime,
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usec_t mtime,
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Image **ret) {
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_cleanup_(image_unrefp) Image *i = NULL;
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assert(t >= 0);
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assert(t < _IMAGE_TYPE_MAX);
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assert(pretty);
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assert(filename);
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assert(ret);
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i = new0(Image, 1);
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if (!i)
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return -ENOMEM;
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i->type = t;
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i->read_only = read_only;
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i->crtime = crtime;
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i->mtime = mtime;
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i->name = strdup(pretty);
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if (!i->name)
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return -ENOMEM;
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if (path)
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i->path = strjoin(path, "/", filename, NULL);
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else
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i->path = strdup(filename);
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if (!i->path)
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return -ENOMEM;
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path_kill_slashes(i->path);
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*ret = i;
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i = NULL;
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return 0;
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}
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static int image_make(
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const char *pretty,
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int dfd,
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const char *path,
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const char *filename,
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Image **ret) {
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struct stat st;
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bool read_only;
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int r;
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assert(filename);
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/* We explicitly *do* follow symlinks here, since we want to
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* allow symlinking trees into /var/lib/container/, and treat
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* them normally. */
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if (fstatat(dfd, filename, &st, 0) < 0)
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return -errno;
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read_only =
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(path && path_startswith(path, "/usr")) ||
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(faccessat(dfd, filename, W_OK, AT_EACCESS) < 0 && errno == EROFS);
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if (S_ISDIR(st.st_mode)) {
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if (!ret)
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return 1;
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if (!pretty)
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pretty = filename;
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/* btrfs subvolumes have inode 256 */
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if (st.st_ino == 256) {
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_cleanup_close_ int fd = -1;
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struct statfs sfs;
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fd = openat(dfd, filename, O_CLOEXEC|O_NOCTTY|O_DIRECTORY);
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if (fd < 0)
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return -errno;
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if (fstatfs(fd, &sfs) < 0)
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return -errno;
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if (F_TYPE_EQUAL(sfs.f_type, BTRFS_SUPER_MAGIC)) {
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BtrfsSubvolInfo info;
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/* It's a btrfs subvolume */
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r = btrfs_subvol_get_info_fd(fd, &info);
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if (r < 0)
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return r;
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r = image_new(IMAGE_SUBVOLUME,
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pretty,
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path,
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filename,
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info.read_only || read_only,
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info.otime,
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0,
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ret);
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if (r < 0)
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return r;
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return 1;
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}
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}
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/* It's just a normal directory. */
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r = image_new(IMAGE_DIRECTORY,
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pretty,
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path,
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filename,
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read_only,
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0,
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0,
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ret);
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if (r < 0)
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return r;
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return 1;
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} else if (S_ISREG(st.st_mode) && endswith(filename, ".gpt")) {
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usec_t crtime = 0;
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/* It's a GPT block device */
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if (!ret)
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return 1;
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fd_getcrtime_at(dfd, filename, &crtime, 0);
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if (!pretty)
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pretty = strndupa(filename, strlen(filename) - 4);
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r = image_new(IMAGE_GPT,
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pretty,
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path,
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filename,
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!(st.st_mode & 0222) || read_only,
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crtime,
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timespec_load(&st.st_mtim),
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ret);
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if (r < 0)
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return r;
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return 1;
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}
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return 0;
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}
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int image_find(const char *name, Image **ret) {
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const char *path;
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int r;
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assert(name);
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/* There are no images with invalid names */
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if (!image_name_is_valid(name))
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return 0;
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NULSTR_FOREACH(path, image_search_path) {
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_cleanup_closedir_ DIR *d = NULL;
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d = opendir(path);
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if (!d) {
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if (errno == ENOENT)
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continue;
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return -errno;
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}
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r = image_make(NULL, dirfd(d), path, name, ret);
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if (r == 0 || r == -ENOENT) {
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_cleanup_free_ char *gpt = NULL;
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gpt = strappend(name, ".gpt");
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if (!gpt)
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return -ENOMEM;
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r = image_make(NULL, dirfd(d), path, gpt, ret);
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if (r == 0 || r == -ENOENT)
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continue;
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}
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if (r < 0)
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return r;
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return 1;
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}
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if (streq(name, ".host"))
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return image_make(".host", AT_FDCWD, NULL, "/", ret);
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return 0;
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};
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int image_discover(Hashmap *h) {
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const char *path;
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int r;
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assert(h);
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NULSTR_FOREACH(path, image_search_path) {
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_cleanup_closedir_ DIR *d = NULL;
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struct dirent *de;
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d = opendir(path);
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if (!d) {
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if (errno == ENOENT)
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continue;
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return -errno;
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}
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FOREACH_DIRENT_ALL(de, d, return -errno) {
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_cleanup_(image_unrefp) Image *image = NULL;
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if (!image_name_is_valid(de->d_name))
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continue;
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if (hashmap_contains(h, de->d_name))
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continue;
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r = image_make(NULL, dirfd(d), path, de->d_name, &image);
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if (r == 0 || r == -ENOENT)
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continue;
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if (r < 0)
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return r;
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r = hashmap_put(h, image->name, image);
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if (r < 0)
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return r;
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image = NULL;
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}
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}
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if (!hashmap_contains(h, ".host")) {
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_cleanup_(image_unrefp) Image *image = NULL;
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r = image_make(".host", AT_FDCWD, NULL, "/", &image);
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if (r < 0)
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return r;
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r = hashmap_put(h, image->name, image);
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if (r < 0)
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return r;
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image = NULL;
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}
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return 0;
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}
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void image_hashmap_free(Hashmap *map) {
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Image *i;
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while ((i = hashmap_steal_first(map)))
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image_unref(i);
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hashmap_free(map);
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}
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static const char* const image_type_table[_IMAGE_TYPE_MAX] = {
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[IMAGE_DIRECTORY] = "directory",
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[IMAGE_SUBVOLUME] = "subvolume",
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[IMAGE_GPT] = "gpt",
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};
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DEFINE_STRING_TABLE_LOOKUP(image_type, ImageType);
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