diff options
Diffstat (limited to '')
| -rw-r--r-- | src/sysext/meson.build | 3 | ||||
| -rw-r--r-- | src/sysext/sysext.c | 1011 |
2 files changed, 1014 insertions, 0 deletions
diff --git a/src/sysext/meson.build b/src/sysext/meson.build new file mode 100644 index 0000000..f159adb --- /dev/null +++ b/src/sysext/meson.build @@ -0,0 +1,3 @@ +# SPDX-License-Identifier: LGPL-2.1-or-later + +systemd_sysext_sources = files('sysext.c') diff --git a/src/sysext/sysext.c b/src/sysext/sysext.c new file mode 100644 index 0000000..ed3fefe --- /dev/null +++ b/src/sysext/sysext.c @@ -0,0 +1,1011 @@ +/* SPDX-License-Identifier: LGPL-2.1-or-later */ + +#include <fcntl.h> +#include <getopt.h> +#include <linux/loop.h> +#include <sys/file.h> +#include <sys/mount.h> +#include <unistd.h> + +#include "capability-util.h" +#include "chase-symlinks.h" +#include "devnum-util.h" +#include "discover-image.h" +#include "dissect-image.h" +#include "env-util.h" +#include "escape.h" +#include "extension-release.h" +#include "fd-util.h" +#include "fileio.h" +#include "format-table.h" +#include "fs-util.h" +#include "hashmap.h" +#include "log.h" +#include "main-func.h" +#include "missing_magic.h" +#include "mkdir.h" +#include "mount-util.h" +#include "mountpoint-util.h" +#include "os-util.h" +#include "pager.h" +#include "parse-argument.h" +#include "parse-util.h" +#include "pretty-print.h" +#include "process-util.h" +#include "sort-util.h" +#include "terminal-util.h" +#include "user-util.h" +#include "verbs.h" + +static char **arg_hierarchies = NULL; /* "/usr" + "/opt" by default */ +static char *arg_root = NULL; +static JsonFormatFlags arg_json_format_flags = JSON_FORMAT_OFF; +static PagerFlags arg_pager_flags = 0; +static bool arg_legend = true; +static bool arg_force = false; + +STATIC_DESTRUCTOR_REGISTER(arg_hierarchies, strv_freep); +STATIC_DESTRUCTOR_REGISTER(arg_root, freep); + +static int is_our_mount_point(const char *p) { + _cleanup_free_ char *buf = NULL, *f = NULL; + struct stat st; + dev_t dev; + int r; + + r = path_is_mount_point(p, NULL, 0); + if (r == -ENOENT) { + log_debug_errno(r, "Hierarchy '%s' doesn't exist.", p); + return false; + } + if (r < 0) + return log_error_errno(r, "Failed to determine whether '%s' is a mount point: %m", p); + if (r == 0) { + log_debug("Hierarchy '%s' is not a mount point, skipping.", p); + return false; + } + + /* So we know now that it's a mount point. Now let's check if it's one of ours, so that we don't + * accidentally unmount the user's own /usr/ but just the mounts we established ourselves. We do this + * check by looking into the metadata directory we place in merged mounts: if the file + * .systemd-sysext/dev contains the major/minor device pair of the mount we have a good reason to + * believe this is one of our mounts. This thorough check has the benefit that we aren't easily + * confused if people tar up one of our merged trees and untar them elsewhere where we might mistake + * them for a live sysext tree. */ + + f = path_join(p, ".systemd-sysext/dev"); + if (!f) + return log_oom(); + + r = read_one_line_file(f, &buf); + if (r == -ENOENT) { + log_debug("Hierarchy '%s' does not carry a .systemd-sysext/dev file, not a sysext merged tree.", p); + return false; + } + if (r < 0) + return log_error_errno(r, "Failed to determine whether hierarchy '%s' contains '.systemd-sysext/dev': %m", p); + + r = parse_devnum(buf, &dev); + if (r < 0) + return log_error_errno(r, "Failed to parse device major/minor stored in '.systemd-sysext/dev' file on '%s': %m", p); + + if (lstat(p, &st) < 0) + return log_error_errno(r, "Failed to stat %s: %m", p); + + if (st.st_dev != dev) { + log_debug("Hierarchy '%s' reports a different device major/minor than what we are seeing, assuming offline copy.", p); + return false; + } + + return true; +} + +static int unmerge_hierarchy(const char *p) { + int r; + + for (;;) { + /* We only unmount /usr/ if it is a mount point and really one of ours, in order not to break + * systems where /usr/ is a mount point of its own already. */ + + r = is_our_mount_point(p); + if (r < 0) + return r; + if (r == 0) + break; + + r = umount_verbose(LOG_ERR, p, MNT_DETACH|UMOUNT_NOFOLLOW); + if (r < 0) + return log_error_errno(r, "Failed to unmount file system '%s': %m", p); + + log_info("Unmerged '%s'.", p); + } + + return 0; +} + +static int unmerge(void) { + int r, ret = 0; + + STRV_FOREACH(p, arg_hierarchies) { + _cleanup_free_ char *resolved = NULL; + + r = chase_symlinks(*p, arg_root, CHASE_PREFIX_ROOT, &resolved, NULL); + if (r == -ENOENT) { + log_debug_errno(r, "Hierarchy '%s%s' does not exist, ignoring.", strempty(arg_root), *p); + continue; + } + if (r < 0) { + log_error_errno(r, "Failed to resolve path to hierarchy '%s%s': %m", strempty(arg_root), *p); + if (ret == 0) + ret = r; + + continue; + } + + r = unmerge_hierarchy(resolved); + if (r < 0 && ret == 0) + ret = r; + } + + return ret; +} + +static int verb_unmerge(int argc, char **argv, void *userdata) { + + if (!have_effective_cap(CAP_SYS_ADMIN)) + return log_error_errno(SYNTHETIC_ERRNO(EPERM), "Need to be privileged."); + + return unmerge(); +} + +static int verb_status(int argc, char **argv, void *userdata) { + _cleanup_(table_unrefp) Table *t = NULL; + int r, ret = 0; + + t = table_new("hierarchy", "extensions", "since"); + if (!t) + return log_oom(); + + table_set_ersatz_string(t, TABLE_ERSATZ_DASH); + + STRV_FOREACH(p, arg_hierarchies) { + _cleanup_free_ char *resolved = NULL, *f = NULL, *buf = NULL; + _cleanup_strv_free_ char **l = NULL; + struct stat st; + + r = chase_symlinks(*p, arg_root, CHASE_PREFIX_ROOT, &resolved, NULL); + if (r == -ENOENT) { + log_debug_errno(r, "Hierarchy '%s%s' does not exist, ignoring.", strempty(arg_root), *p); + continue; + } + if (r < 0) { + log_error_errno(r, "Failed to resolve path to hierarchy '%s%s': %m", strempty(arg_root), *p); + goto inner_fail; + } + + r = is_our_mount_point(resolved); + if (r < 0) + goto inner_fail; + if (r == 0) { + r = table_add_many( + t, + TABLE_PATH, *p, + TABLE_STRING, "none", + TABLE_SET_COLOR, ansi_grey(), + TABLE_EMPTY); + if (r < 0) + return table_log_add_error(r); + + continue; + } + + f = path_join(*p, ".systemd-sysext/extensions"); + if (!f) + return log_oom(); + + r = read_full_file(f, &buf, NULL); + if (r < 0) + return log_error_errno(r, "Failed to open '%s': %m", f); + + l = strv_split_newlines(buf); + if (!l) + return log_oom(); + + if (stat(*p, &st) < 0) + return log_error_errno(r, "Failed to stat() '%s': %m", *p); + + r = table_add_many( + t, + TABLE_PATH, *p, + TABLE_STRV, l, + TABLE_TIMESTAMP, timespec_load(&st.st_mtim)); + if (r < 0) + return table_log_add_error(r); + + continue; + + inner_fail: + if (ret == 0) + ret = r; + } + + (void) table_set_sort(t, (size_t) 0); + + r = table_print_with_pager(t, arg_json_format_flags, arg_pager_flags, arg_legend); + if (r < 0) + return r; + + return ret; +} + +static int mount_overlayfs( + const char *where, + char **layers) { + + _cleanup_free_ char *options = NULL; + bool separator = false; + int r; + + assert(where); + + options = strdup("lowerdir="); + if (!options) + return log_oom(); + + STRV_FOREACH(l, layers) { + _cleanup_free_ char *escaped = NULL; + + escaped = shell_escape(*l, ",:"); + if (!escaped) + return log_oom(); + + if (!strextend(&options, separator ? ":" : "", escaped)) + return log_oom(); + + separator = true; + } + + /* Now mount the actual overlayfs */ + r = mount_nofollow_verbose(LOG_ERR, "sysext", where, "overlay", MS_RDONLY, options); + if (r < 0) + return r; + + return 0; +} + +static int merge_hierarchy( + const char *hierarchy, + char **extensions, + char **paths, + const char *meta_path, + const char *overlay_path) { + + _cleanup_free_ char *resolved_hierarchy = NULL, *f = NULL, *buf = NULL; + _cleanup_strv_free_ char **layers = NULL; + struct stat st; + int r; + + assert(hierarchy); + assert(meta_path); + assert(overlay_path); + + /* Resolve the path of the host's version of the hierarchy, i.e. what we want to use as lowest layer + * in the overlayfs stack. */ + r = chase_symlinks(hierarchy, arg_root, CHASE_PREFIX_ROOT, &resolved_hierarchy, NULL); + if (r == -ENOENT) + log_debug_errno(r, "Hierarchy '%s' on host doesn't exist, not merging.", hierarchy); + else if (r < 0) + return log_error_errno(r, "Failed to resolve host hierarchy '%s': %m", hierarchy); + else { + r = dir_is_empty(resolved_hierarchy, /* ignore_hidden_or_backup= */ false); + if (r < 0) + return log_error_errno(r, "Failed to check if host hierarchy '%s' is empty: %m", resolved_hierarchy); + if (r > 0) { + log_debug("Host hierarchy '%s' is empty, not merging.", resolved_hierarchy); + resolved_hierarchy = mfree(resolved_hierarchy); + } + } + + /* Let's generate a metadata file that lists all extensions we took into account for this + * hierarchy. We include this in the final fs, to make things nicely discoverable and + * recognizable. */ + f = path_join(meta_path, ".systemd-sysext/extensions"); + if (!f) + return log_oom(); + + buf = strv_join(extensions, "\n"); + if (!buf) + return log_oom(); + + r = write_string_file(f, buf, WRITE_STRING_FILE_CREATE|WRITE_STRING_FILE_MKDIR_0755); + if (r < 0) + return log_error_errno(r, "Failed to write extension meta file '%s': %m", f); + + /* Put the meta path (i.e. our synthesized stuff) at the top of the layer stack */ + layers = strv_new(meta_path); + if (!layers) + return log_oom(); + + /* Put the extensions in the middle */ + STRV_FOREACH(p, paths) { + _cleanup_free_ char *resolved = NULL; + + r = chase_symlinks(hierarchy, *p, CHASE_PREFIX_ROOT, &resolved, NULL); + if (r == -ENOENT) { + log_debug_errno(r, "Hierarchy '%s' in extension '%s' doesn't exist, not merging.", hierarchy, *p); + continue; + } + if (r < 0) + return log_error_errno(r, "Failed to resolve hierarchy '%s' in extension '%s': %m", hierarchy, *p); + + r = dir_is_empty(resolved, /* ignore_hidden_or_backup= */ false); + if (r < 0) + return log_error_errno(r, "Failed to check if hierarchy '%s' in extension '%s' is empty: %m", resolved, *p); + if (r > 0) { + log_debug("Hierarchy '%s' in extension '%s' is empty, not merging.", hierarchy, *p); + continue; + } + + r = strv_consume(&layers, TAKE_PTR(resolved)); + if (r < 0) + return log_oom(); + } + + if (!layers[1]) /* No extension with files in this hierarchy? Then don't do anything. */ + return 0; + + if (resolved_hierarchy) { + /* Add the host hierarchy as last (lowest) layer in the stack */ + r = strv_consume(&layers, TAKE_PTR(resolved_hierarchy)); + if (r < 0) + return log_oom(); + } + + r = mkdir_p(overlay_path, 0700); + if (r < 0) + return log_error_errno(r, "Failed to make directory '%s': %m", overlay_path); + + r = mount_overlayfs(overlay_path, layers); + if (r < 0) + return r; + + /* The overlayfs superblock is read-only. Let's also mark the bind mount read-only. Extra turbo safety 😎 */ + r = bind_remount_recursive(overlay_path, MS_RDONLY, MS_RDONLY, NULL); + if (r < 0) + return log_error_errno(r, "Failed to make bind mount '%s' read-only: %m", overlay_path); + + /* Now we have mounted the new file system. Let's now figure out its .st_dev field, and make that + * available in the metadata directory. This is useful to detect whether the metadata dir actually + * belongs to the fs it is found on: if .st_dev of the top-level mount matches it, it's pretty likely + * we are looking at a live sysext tree, and not an unpacked tar or so of one. */ + if (stat(overlay_path, &st) < 0) + return log_error_errno(r, "Failed to stat mount '%s': %m", overlay_path); + + free(f); + f = path_join(meta_path, ".systemd-sysext/dev"); + if (!f) + return log_oom(); + + r = write_string_filef(f, WRITE_STRING_FILE_CREATE, "%u:%u", major(st.st_dev), minor(st.st_dev)); + if (r < 0) + return log_error_errno(r, "Failed to write '%s': %m", f); + + /* Make sure the top-level dir has an mtime marking the point we established the merge */ + if (utimensat(AT_FDCWD, meta_path, NULL, AT_SYMLINK_NOFOLLOW) < 0) + return log_error_errno(r, "Failed fix mtime of '%s': %m", meta_path); + + return 1; +} + +static int strverscmp_improvedp(char *const* a, char *const* b) { + /* usable in qsort() for sorting a string array with strverscmp_improved() */ + return strverscmp_improved(*a, *b); +} + +static int validate_version( + const char *root, + const Image *img, + const char *host_os_release_id, + const char *host_os_release_version_id, + const char *host_os_release_sysext_level) { + + int r; + + assert(root); + assert(img); + + if (arg_force) { + log_debug("Force mode enabled, skipping version validation."); + return 1; + } + + /* Insist that extension images do not overwrite the underlying OS release file (it's fine if + * they place one in /etc/os-release, i.e. where things don't matter, as they aren't + * merged.) */ + r = chase_symlinks("/usr/lib/os-release", root, CHASE_PREFIX_ROOT, NULL, NULL); + if (r < 0) { + if (r != -ENOENT) + return log_error_errno(r, "Failed to determine whether /usr/lib/os-release exists in the extension image: %m"); + } else + return log_error_errno(SYNTHETIC_ERRNO(EINVAL), + "Extension image contains /usr/lib/os-release file, which is not allowed (it may carry /etc/os-release), refusing."); + + r = extension_release_validate( + img->name, + host_os_release_id, + host_os_release_version_id, + host_os_release_sysext_level, + in_initrd() ? "initrd" : "system", + img->extension_release); + if (r < 0) + return log_error_errno(r, "Failed to validate extension release information: %m"); + + return r; +} + +static int merge_subprocess(Hashmap *images, const char *workspace) { + _cleanup_free_ char *host_os_release_id = NULL, *host_os_release_version_id = NULL, *host_os_release_sysext_level = NULL, + *buf = NULL; + _cleanup_strv_free_ char **extensions = NULL, **paths = NULL; + size_t n_extensions = 0; + unsigned n_ignored = 0; + Image *img; + int r; + + /* Mark the whole of /run as MS_SLAVE, so that we can mount stuff below it that doesn't show up on + * the host otherwise. */ + r = mount_nofollow_verbose(LOG_ERR, NULL, "/run", NULL, MS_SLAVE|MS_REC, NULL); + if (r < 0) + return log_error_errno(r, "Failed to remount /run/ MS_SLAVE: %m"); + + /* Let's create the workspace if it's missing */ + r = mkdir_p(workspace, 0700); + if (r < 0) + return log_error_errno(r, "Failed to create /run/systemd/sysext: %m"); + + /* Let's mount a tmpfs to our workspace. This way we don't need to clean up the inodes we mount over, + * but let the kernel do that entirely automatically, once our namespace dies. Note that this file + * system won't be visible to anyone but us, since we opened our own namespace and then made the + * /run/ hierarchy (which our workspace is contained in) MS_SLAVE, see above. */ + r = mount_nofollow_verbose(LOG_ERR, "sysext", workspace, "tmpfs", 0, "mode=0700"); + if (r < 0) + return r; + + /* Acquire host OS release info, so that we can compare it with the extension's data */ + r = parse_os_release( + arg_root, + "ID", &host_os_release_id, + "VERSION_ID", &host_os_release_version_id, + "SYSEXT_LEVEL", &host_os_release_sysext_level); + if (r < 0) + return log_error_errno(r, "Failed to acquire 'os-release' data of OS tree '%s': %m", empty_to_root(arg_root)); + if (isempty(host_os_release_id)) + return log_error_errno(SYNTHETIC_ERRNO(EINVAL), + "'ID' field not found or empty in 'os-release' data of OS tree '%s': %m", + empty_to_root(arg_root)); + + /* Let's now mount all images */ + HASHMAP_FOREACH(img, images) { + _cleanup_free_ char *p = NULL; + + p = path_join(workspace, "extensions", img->name); + if (!p) + return log_oom(); + + r = mkdir_p(p, 0700); + if (r < 0) + return log_error_errno(r, "Failed to create %s: %m", p); + + switch (img->type) { + case IMAGE_DIRECTORY: + case IMAGE_SUBVOLUME: + r = mount_nofollow_verbose(LOG_ERR, img->path, p, NULL, MS_BIND, NULL); + if (r < 0) + return r; + + /* Make this a read-only bind mount */ + r = bind_remount_recursive(p, MS_RDONLY, MS_RDONLY, NULL); + if (r < 0) + return log_error_errno(r, "Failed to make bind mount '%s' read-only: %m", p); + + break; + + case IMAGE_RAW: + case IMAGE_BLOCK: { + _cleanup_(dissected_image_unrefp) DissectedImage *m = NULL; + _cleanup_(loop_device_unrefp) LoopDevice *d = NULL; + _cleanup_(verity_settings_done) VeritySettings verity_settings = VERITY_SETTINGS_DEFAULT; + DissectImageFlags flags = + DISSECT_IMAGE_READ_ONLY | + DISSECT_IMAGE_GENERIC_ROOT | + DISSECT_IMAGE_REQUIRE_ROOT | + DISSECT_IMAGE_MOUNT_ROOT_ONLY | + DISSECT_IMAGE_USR_NO_ROOT | + DISSECT_IMAGE_ADD_PARTITION_DEVICES | + DISSECT_IMAGE_PIN_PARTITION_DEVICES; + + r = verity_settings_load(&verity_settings, img->path, NULL, NULL); + if (r < 0) + return log_error_errno(r, "Failed to read verity artifacts for %s: %m", img->path); + + if (verity_settings.data_path) + flags |= DISSECT_IMAGE_NO_PARTITION_TABLE; + + r = loop_device_make_by_path( + img->path, + O_RDONLY, + FLAGS_SET(flags, DISSECT_IMAGE_NO_PARTITION_TABLE) ? 0 : LO_FLAGS_PARTSCAN, + LOCK_SH, + &d); + if (r < 0) + return log_error_errno(r, "Failed to set up loopback device for %s: %m", img->path); + + r = dissect_loop_device_and_warn( + d, + &verity_settings, + NULL, + flags, + &m); + if (r < 0) + return r; + + r = dissected_image_load_verity_sig_partition( + m, + d->fd, + &verity_settings); + if (r < 0) + return r; + + r = dissected_image_decrypt_interactively( + m, NULL, + &verity_settings, + flags); + if (r < 0) + return r; + + r = dissected_image_mount_and_warn( + m, + p, + UID_INVALID, + UID_INVALID, + flags); + if (r < 0) + return r; + + r = dissected_image_relinquish(m); + if (r < 0) + return log_error_errno(r, "Failed to relinquish DM and loopback block devices: %m"); + break; + } + default: + assert_not_reached(); + } + + r = validate_version( + p, + img, + host_os_release_id, + host_os_release_version_id, + host_os_release_sysext_level); + if (r < 0) + return r; + if (r == 0) { + n_ignored++; + continue; + } + + /* Nice! This one is an extension we want. */ + r = strv_extend(&extensions, img->name); + if (r < 0) + return log_oom(); + + n_extensions ++; + } + + /* Nothing left? Then shortcut things */ + if (n_extensions == 0) { + if (n_ignored > 0) + log_info("No suitable extensions found (%u ignored due to incompatible version).", n_ignored); + else + log_info("No extensions found."); + return 0; + } + + /* Order by version sort with strverscmp_improved() */ + typesafe_qsort(extensions, n_extensions, strverscmp_improvedp); + + buf = strv_join(extensions, "', '"); + if (!buf) + return log_oom(); + + log_info("Using extensions '%s'.", buf); + + /* Build table of extension paths (in reverse order) */ + paths = new0(char*, n_extensions + 1); + if (!paths) + return log_oom(); + + for (size_t k = 0; k < n_extensions; k++) { + _cleanup_free_ char *p = NULL; + + assert_se(img = hashmap_get(images, extensions[n_extensions - 1 - k])); + + p = path_join(workspace, "extensions", img->name); + if (!p) + return log_oom(); + + paths[k] = TAKE_PTR(p); + } + + /* Let's now unmerge the status quo ante, since to build the new overlayfs we need a reference to the + * underlying fs. */ + STRV_FOREACH(h, arg_hierarchies) { + _cleanup_free_ char *resolved = NULL; + + r = chase_symlinks(*h, arg_root, CHASE_PREFIX_ROOT|CHASE_NONEXISTENT, &resolved, NULL); + if (r < 0) + return log_error_errno(r, "Failed to resolve hierarchy '%s%s': %m", strempty(arg_root), *h); + + r = unmerge_hierarchy(resolved); + if (r < 0) + return r; + } + + /* Create overlayfs mounts for all hierarchies */ + STRV_FOREACH(h, arg_hierarchies) { + _cleanup_free_ char *meta_path = NULL, *overlay_path = NULL; + + meta_path = path_join(workspace, "meta", *h); /* The place where to store metadata about this instance */ + if (!meta_path) + return log_oom(); + + overlay_path = path_join(workspace, "overlay", *h); /* The resulting overlayfs instance */ + if (!overlay_path) + return log_oom(); + + r = merge_hierarchy(*h, extensions, paths, meta_path, overlay_path); + if (r < 0) + return r; + } + + /* And move them all into place. This is where things appear in the host namespace */ + STRV_FOREACH(h, arg_hierarchies) { + _cleanup_free_ char *p = NULL, *resolved = NULL; + + p = path_join(workspace, "overlay", *h); + if (!p) + return log_oom(); + + if (laccess(p, F_OK) < 0) { + if (errno != ENOENT) + return log_error_errno(errno, "Failed to check if '%s' exists: %m", p); + + /* Hierarchy apparently was empty in all extensions, and wasn't mounted, ignoring. */ + continue; + } + + r = chase_symlinks(*h, arg_root, CHASE_PREFIX_ROOT|CHASE_NONEXISTENT, &resolved, NULL); + if (r < 0) + return log_error_errno(r, "Failed to resolve hierarchy '%s%s': %m", strempty(arg_root), *h); + + r = mkdir_p(resolved, 0755); + if (r < 0) + return log_error_errno(r, "Failed to create hierarchy mount point '%s': %m", resolved); + + r = mount_nofollow_verbose(LOG_ERR, p, resolved, NULL, MS_BIND, NULL); + if (r < 0) + return r; + + log_info("Merged extensions into '%s'.", resolved); + } + + return 1; +} + +static int merge(Hashmap *images) { + pid_t pid; + int r; + + r = safe_fork("(sd-sysext)", FORK_DEATHSIG|FORK_LOG|FORK_NEW_MOUNTNS, &pid); + if (r < 0) + return log_error_errno(r, "Failed to fork off child: %m"); + if (r == 0) { + /* Child with its own mount namespace */ + + r = merge_subprocess(images, "/run/systemd/sysext"); + if (r < 0) + _exit(EXIT_FAILURE); + + /* Our namespace ceases to exist here, also implicitly detaching all temporary mounts we + * created below /run. Nice! */ + + _exit(r > 0 ? EXIT_SUCCESS : 123); /* 123 means: didn't find any extensions */ + } + + r = wait_for_terminate_and_check("(sd-sysext)", pid, WAIT_LOG_ABNORMAL); + if (r < 0) + return r; + + return r != 123; /* exit code 123 means: didn't do anything */ +} + +static int image_discover_and_read_metadata(Hashmap **ret_images) { + _cleanup_(hashmap_freep) Hashmap *images = NULL; + Image *img; + int r; + + assert(ret_images); + + images = hashmap_new(&image_hash_ops); + if (!images) + return log_oom(); + + r = image_discover(IMAGE_EXTENSION, arg_root, images); + if (r < 0) + return log_error_errno(r, "Failed to discover extension images: %m"); + + HASHMAP_FOREACH(img, images) { + r = image_read_metadata(img); + if (r < 0) + return log_error_errno(r, "Failed to read metadata for image %s: %m", img->name); + } + + *ret_images = TAKE_PTR(images); + + return 0; +} + +static int verb_merge(int argc, char **argv, void *userdata) { + _cleanup_(hashmap_freep) Hashmap *images = NULL; + int r; + + if (!have_effective_cap(CAP_SYS_ADMIN)) + return log_error_errno(SYNTHETIC_ERRNO(EPERM), "Need to be privileged."); + + r = image_discover_and_read_metadata(&images); + if (r < 0) + return r; + + /* In merge mode fail if things are already merged. (In --refresh mode below we'll unmerge if we find + * things are already merged...) */ + STRV_FOREACH(p, arg_hierarchies) { + _cleanup_free_ char *resolved = NULL; + + r = chase_symlinks(*p, arg_root, CHASE_PREFIX_ROOT, &resolved, NULL); + if (r == -ENOENT) { + log_debug_errno(r, "Hierarchy '%s%s' does not exist, ignoring.", strempty(arg_root), *p); + continue; + } + if (r < 0) + return log_error_errno(r, "Failed to resolve path to hierarchy '%s%s': %m", strempty(arg_root), *p); + + r = is_our_mount_point(resolved); + if (r < 0) + return r; + if (r > 0) + return log_error_errno(SYNTHETIC_ERRNO(EBUSY), + "Hierarchy '%s' is already merged.", *p); + } + + return merge(images); +} + +static int verb_refresh(int argc, char **argv, void *userdata) { + _cleanup_(hashmap_freep) Hashmap *images = NULL; + int r; + + if (!have_effective_cap(CAP_SYS_ADMIN)) + return log_error_errno(SYNTHETIC_ERRNO(EPERM), "Need to be privileged."); + + r = image_discover_and_read_metadata(&images); + if (r < 0) + return r; + + r = merge(images); /* Returns > 0 if it did something, i.e. a new overlayfs is mounted now. When it + * does so it implicitly unmounts any overlayfs placed there before. Returns == 0 + * if it did nothing, i.e. no extension images found. In this case the old + * overlayfs remains in place if there was one. */ + if (r < 0) + return r; + if (r == 0) /* No images found? Then unmerge. The goal of --refresh is after all that after having + * called there's a guarantee that the merge status matches the installed extensions. */ + r = unmerge(); + + /* Net result here is that: + * + * 1. If an overlayfs was mounted before and no extensions exist anymore, we'll have unmerged things. + * + * 2. If an overlayfs was mounted before, and there are still extensions installed' we'll have + * unmerged and then merged things again. + * + * 3. If an overlayfs so far wasn't mounted, and there are extensions installed, we'll have it + * mounted now. + * + * 4. If there was no overlayfs mount so far, and no extensions installed, we implement a NOP. + */ + + return 0; +} + +static int verb_list(int argc, char **argv, void *userdata) { + _cleanup_(hashmap_freep) Hashmap *images = NULL; + _cleanup_(table_unrefp) Table *t = NULL; + Image *img; + int r; + + images = hashmap_new(&image_hash_ops); + if (!images) + return log_oom(); + + r = image_discover(IMAGE_EXTENSION, arg_root, images); + if (r < 0) + return log_error_errno(r, "Failed to discover extension images: %m"); + + if ((arg_json_format_flags & JSON_FORMAT_OFF) && hashmap_isempty(images)) { + log_info("No OS extensions found."); + return 0; + } + + t = table_new("name", "type", "path", "time"); + if (!t) + return log_oom(); + + HASHMAP_FOREACH(img, images) { + r = table_add_many( + t, + TABLE_STRING, img->name, + TABLE_STRING, image_type_to_string(img->type), + TABLE_PATH, img->path, + TABLE_TIMESTAMP, img->mtime != 0 ? img->mtime : img->crtime); + if (r < 0) + return table_log_add_error(r); + } + + (void) table_set_sort(t, (size_t) 0); + + return table_print_with_pager(t, arg_json_format_flags, arg_pager_flags, arg_legend); +} + +static int verb_help(int argc, char **argv, void *userdata) { + _cleanup_free_ char *link = NULL; + int r; + + r = terminal_urlify_man("systemd-sysext", "8", &link); + if (r < 0) + return log_oom(); + + printf("%1$s [OPTIONS...] COMMAND\n" + "\n%5$sMerge extension images into /usr/ and /opt/ hierarchies.%6$s\n" + "\n%3$sCommands:%4$s\n" + " status Show current merge status (default)\n" + " merge Merge extensions into /usr/ and /opt/\n" + " unmerge Unmerge extensions from /usr/ and /opt/\n" + " refresh Unmerge/merge extensions again\n" + " list List installed extensions\n" + " -h --help Show this help\n" + " --version Show package version\n" + "\n%3$sOptions:%4$s\n" + " --no-pager Do not pipe output into a pager\n" + " --no-legend Do not show the headers and footers\n" + " --root=PATH Operate relative to root path\n" + " --json=pretty|short|off\n" + " Generate JSON output\n" + " --force Ignore version incompatibilities\n" + "\nSee the %2$s for details.\n", + program_invocation_short_name, + link, + ansi_underline(), + ansi_normal(), + ansi_highlight(), + ansi_normal()); + + return 0; +} + +static int parse_argv(int argc, char *argv[]) { + + enum { + ARG_VERSION = 0x100, + ARG_NO_PAGER, + ARG_NO_LEGEND, + ARG_ROOT, + ARG_JSON, + ARG_FORCE, + }; + + static const struct option options[] = { + { "help", no_argument, NULL, 'h' }, + { "version", no_argument, NULL, ARG_VERSION }, + { "no-pager", no_argument, NULL, ARG_NO_PAGER }, + { "no-legend", no_argument, NULL, ARG_NO_LEGEND }, + { "root", required_argument, NULL, ARG_ROOT }, + { "json", required_argument, NULL, ARG_JSON }, + { "force", no_argument, NULL, ARG_FORCE }, + {} + }; + + int c, r; + + assert(argc >= 0); + assert(argv); + + while ((c = getopt_long(argc, argv, "h", options, NULL)) >= 0) + + switch (c) { + + case 'h': + return verb_help(argc, argv, NULL); + + case ARG_VERSION: + return version(); + + case ARG_NO_PAGER: + arg_pager_flags |= PAGER_DISABLE; + break; + + case ARG_NO_LEGEND: + arg_legend = false; + break; + + case ARG_ROOT: + r = parse_path_argument(optarg, false, &arg_root); + if (r < 0) + return r; + break; + + case ARG_JSON: + r = parse_json_argument(optarg, &arg_json_format_flags); + if (r <= 0) + return r; + + break; + + case ARG_FORCE: + arg_force = true; + break; + + case '?': + return -EINVAL; + + default: + assert_not_reached(); + } + + return 1; +} + +static int sysext_main(int argc, char *argv[]) { + + static const Verb verbs[] = { + { "status", VERB_ANY, 1, VERB_DEFAULT, verb_status }, + { "merge", VERB_ANY, 1, 0, verb_merge }, + { "unmerge", VERB_ANY, 1, 0, verb_unmerge }, + { "refresh", VERB_ANY, 1, 0, verb_refresh }, + { "list", VERB_ANY, 1, 0, verb_list }, + { "help", VERB_ANY, 1, 0, verb_help }, + {} + }; + + return dispatch_verb(argc, argv, verbs, NULL); +} + +static int run(int argc, char *argv[]) { + int r; + + log_setup(); + + r = parse_argv(argc, argv); + if (r <= 0) + return r; + + /* For debugging purposes it might make sense to do this for other hierarchies than /usr/ and + * /opt/, but let's make that a hacker/debugging feature, i.e. env var instead of cmdline + * switch. */ + r = parse_env_extension_hierarchies(&arg_hierarchies); + if (r < 0) + return log_error_errno(r, "Failed to parse $SYSTEMD_SYSEXT_HIERARCHIES environment variable: %m"); + + return sysext_main(argc, argv); +} + +DEFINE_MAIN_FUNCTION(run); |