machine-image: add a generic API to determine metadata of any image
This adds an internal API that permits querying metadata from any type of image, including both subvol/dir images, and raw/block images. In the latter case we use the new dissection API we just added.
This commit is contained in:
Lennart Poettering
parent
a1edd22e67
commit
c7664c071e
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@ -34,12 +34,17 @@
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#include "chattr-util.h"
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#include "copy.h"
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#include "dirent-util.h"
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#include "dissect-image.h"
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#include "env-util.h"
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#include "fd-util.h"
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#include "fileio.h"
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#include "fs-util.h"
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#include "hashmap.h"
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#include "hostname-util.h"
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#include "id128-util.h"
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#include "lockfile-util.h"
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#include "log.h"
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#include "loop-util.h"
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#include "machine-image.h"
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#include "macro.h"
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#include "mkdir.h"
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@ -65,6 +70,11 @@ Image *image_unref(Image *i) {
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free(i->name);
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free(i->path);
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free(i->hostname);
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strv_free(i->machine_info);
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strv_free(i->os_release);
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return mfree(i);
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}
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@ -761,6 +771,7 @@ int image_clone(Image *i, const char *new_name, bool read_only) {
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int image_read_only(Image *i, bool b) {
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_cleanup_release_lock_file_ LockFile global_lock = LOCK_FILE_INIT, local_lock = LOCK_FILE_INIT;
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int r;
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assert(i);
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if (IMAGE_IS_VENDOR(i) || IMAGE_IS_HOST(i))
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@ -924,6 +935,118 @@ int image_set_limit(Image *i, uint64_t referenced_max) {
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return btrfs_subvol_set_subtree_quota_limit(i->path, 0, referenced_max);
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}
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int image_read_metadata(Image *i) {
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_cleanup_release_lock_file_ LockFile global_lock = LOCK_FILE_INIT, local_lock = LOCK_FILE_INIT;
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int r;
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assert(i);
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r = image_path_lock(i->path, LOCK_SH|LOCK_NB, &global_lock, &local_lock);
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if (r < 0)
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return r;
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switch (i->type) {
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case IMAGE_SUBVOLUME:
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case IMAGE_DIRECTORY: {
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_cleanup_strv_free_ char **machine_info = NULL, **os_release = NULL;
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sd_id128_t machine_id = SD_ID128_NULL;
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_cleanup_free_ char *hostname = NULL;
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_cleanup_free_ char *path = NULL;
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r = chase_symlinks("/etc/hostname", i->path, CHASE_PREFIX_ROOT, &path);
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if (r < 0 && r != -ENOENT)
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log_debug_errno(r, "Failed to chase /etc/hostname in image %s: %m", i->name);
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else if (r >= 0) {
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r = read_etc_hostname(path, &hostname);
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if (r < 0)
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log_debug_errno(errno, "Failed to read /etc/hostname of image %s: %m", i->name);
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}
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path = mfree(path);
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r = chase_symlinks("/etc/machine-id", i->path, CHASE_PREFIX_ROOT, &path);
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if (r < 0 && r != -ENOENT)
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log_debug_errno(r, "Failed to chase /etc/machine-id in image %s: %m", i->name);
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else if (r >= 0) {
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_cleanup_close_ int fd = -1;
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fd = open(path, O_RDONLY|O_CLOEXEC|O_NOCTTY);
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if (fd < 0)
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log_debug_errno(errno, "Failed to open %s: %m", path);
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else {
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r = id128_read_fd(fd, ID128_PLAIN, &machine_id);
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if (r < 0)
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log_debug_errno(r, "Image %s contains invalid machine ID.", i->name);
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}
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}
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path = mfree(path);
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r = chase_symlinks("/etc/machine-info", i->path, CHASE_PREFIX_ROOT, &path);
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if (r < 0 && r != -ENOENT)
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log_debug_errno(r, "Failed to chase /etc/machine-info in image %s: %m", i->name);
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else if (r >= 0) {
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r = load_env_file_pairs(NULL, path, NULL, &machine_info);
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if (r < 0)
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log_debug_errno(r, "Failed to parse machine-info data of %s: %m", i->name);
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}
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path = mfree(path);
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r = chase_symlinks("/etc/os-release", i->path, CHASE_PREFIX_ROOT, &path);
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if (r == -ENOENT)
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r = chase_symlinks("/usr/lib/os-release", i->path, CHASE_PREFIX_ROOT, &path);
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if (r < 0 && r != -ENOENT)
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log_debug_errno(r, "Failed to chase os-release in image: %m");
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else if (r >= 0) {
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r = load_env_file_pairs(NULL, path, NULL, &os_release);
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if (r < 0)
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log_debug_errno(r, "Failed to parse os-release data of %s: %m", i->name);
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}
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free_and_replace(i->hostname, hostname);
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i->machine_id = machine_id;
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strv_free_and_replace(i->machine_info, machine_info);
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strv_free_and_replace(i->os_release, os_release);
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break;
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}
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case IMAGE_RAW:
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case IMAGE_BLOCK: {
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_cleanup_(loop_device_unrefp) LoopDevice *d = NULL;
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_cleanup_(dissected_image_unrefp) DissectedImage *m = NULL;
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r = loop_device_make_by_path(i->path, O_RDONLY, &d);
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if (r < 0)
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return r;
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r = dissect_image(d->fd, NULL, 0, DISSECT_IMAGE_REQUIRE_ROOT, &m);
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if (r < 0)
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return r;
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r = dissected_image_acquire_metadata(m);
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if (r < 0)
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return r;
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free_and_replace(i->hostname, m->hostname);
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i->machine_id = m->machine_id;
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strv_free_and_replace(i->machine_info, m->machine_info);
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strv_free_and_replace(i->os_release, m->os_release);
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break;
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}
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default:
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return -EOPNOTSUPP;
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}
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i->metadata_valid = true;
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return 0;
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}
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int image_name_lock(const char *name, int operation, LockFile *ret) {
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const char *p;
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@ -53,6 +53,13 @@ typedef struct Image {
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uint64_t limit;
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uint64_t limit_exclusive;
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char *hostname;
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sd_id128_t machine_id;
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char **machine_info;
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char **os_release;
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bool metadata_valid;
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void *userdata;
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} Image;
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@ -80,6 +87,8 @@ int image_name_lock(const char *name, int operation, LockFile *ret);
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int image_set_limit(Image *i, uint64_t referenced_max);
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int image_read_metadata(Image *i);
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static inline bool IMAGE_IS_HIDDEN(const struct Image *i) {
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assert(i);
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