diff --git a/meson.build b/meson.build index c12b399b5f..ed01c369b1 100644 --- a/meson.build +++ b/meson.build @@ -1502,6 +1502,7 @@ foreach term : ['analyze', 'nss-myhostname', 'nss-systemd', 'portabled', + 'sysext', 'pstore', 'quotacheck', 'randomseed', @@ -1745,6 +1746,7 @@ subdir('src/portable') subdir('src/pstore') subdir('src/resolve') subdir('src/shutdown') +subdir('src/sysext') subdir('src/systemctl') subdir('src/timedate') subdir('src/timesync') @@ -2202,6 +2204,17 @@ if conf.get('ENABLE_PORTABLED') == 1 install_dir : rootbindir) endif +if conf.get('ENABLE_SYSEXT') == 1 + public_programs += executable( + 'systemd-sysext', + systemd_sysext_sources, + include_directories : includes, + link_with : [libshared], + install_rpath : rootlibexecdir, + install : true, + install_dir : rootbindir) +endif + if conf.get('ENABLE_USERDB') == 1 executable( 'systemd-userwork', @@ -3735,6 +3748,7 @@ foreach tuple : [ ['logind'], ['machined'], ['portabled'], + ['sysext'], ['userdb'], ['homed'], ['importd'], diff --git a/meson_options.txt b/meson_options.txt index 1707f64c17..a421473029 100644 --- a/meson_options.txt +++ b/meson_options.txt @@ -111,6 +111,8 @@ option('machined', type : 'boolean', description : 'install the systemd-machined stack') option('portabled', type : 'boolean', description : 'install the systemd-portabled stack') +option('sysext', type : 'boolean', + description : 'install the systemd-sysext stack') option('userdb', type : 'boolean', description : 'install the systemd-userdbd stack') option('homed', type : 'combo', choices : ['auto', 'true', 'false'], diff --git a/src/shared/machine-image.c b/src/shared/machine-image.c index df288bc0e1..f7b1f90c6f 100644 --- a/src/shared/machine-image.c +++ b/src/shared/machine-image.c @@ -42,18 +42,24 @@ #include "xattr-util.h" static const char* const image_search_path[_IMAGE_CLASS_MAX] = { - [IMAGE_MACHINE] = "/etc/machines\0" /* only place symlinks here */ - "/run/machines\0" /* and here too */ - "/var/lib/machines\0" /* the main place for images */ - "/var/lib/container\0" /* legacy */ - "/usr/local/lib/machines\0" - "/usr/lib/machines\0", + [IMAGE_MACHINE] = "/etc/machines\0" /* only place symlinks here */ + "/run/machines\0" /* and here too */ + "/var/lib/machines\0" /* the main place for images */ + "/var/lib/container\0" /* legacy */ + "/usr/local/lib/machines\0" + "/usr/lib/machines\0", - [IMAGE_PORTABLE] = "/etc/portables\0" /* only place symlinks here */ - "/run/portables\0" /* and here too */ - "/var/lib/portables\0" /* the main place for images */ - "/usr/local/lib/portables\0" - "/usr/lib/portables\0", + [IMAGE_PORTABLE] = "/etc/portables\0" /* only place symlinks here */ + "/run/portables\0" /* and here too */ + "/var/lib/portables\0" /* the main place for images */ + "/usr/local/lib/portables\0" + "/usr/lib/portables\0", + + [IMAGE_EXTENSION] = "/etc/extensions\0" /* only place symlinks here */ + "/run/extensions\0" /* and here too */ + "/var/lib/extensions\0" /* the main place for images */ + "/usr/local/lib/extensions\0" + "/usr/lib/extensions\0", }; static Image *image_free(Image *i) { diff --git a/src/shared/machine-image.h b/src/shared/machine-image.h index 95a8f5cfbd..eea94e0324 100644 --- a/src/shared/machine-image.h +++ b/src/shared/machine-image.h @@ -16,6 +16,7 @@ typedef enum ImageClass { IMAGE_MACHINE, IMAGE_PORTABLE, + IMAGE_EXTENSION, _IMAGE_CLASS_MAX, _IMAGE_CLASS_INVALID = -1 } ImageClass; diff --git a/src/sysext/meson.build b/src/sysext/meson.build new file mode 100644 index 0000000000..1517df414e --- /dev/null +++ b/src/sysext/meson.build @@ -0,0 +1,5 @@ +# SPDX-License-Identifier: LGPL-2.1-or-later + +systemd_sysext_sources = files(''' + sysext.c +'''.split()) diff --git a/src/sysext/sysext.c b/src/sysext/sysext.c new file mode 100644 index 0000000000..4f92d563af --- /dev/null +++ b/src/sysext/sysext.c @@ -0,0 +1,1007 @@ +/* SPDX-License-Identifier: LGPL-2.1-or-later */ + +#include +#include +#include +#include + +#include "capability-util.h" +#include "dissect-image.h" +#include "escape.h" +#include "fd-util.h" +#include "fileio.h" +#include "format-table.h" +#include "fs-util.h" +#include "hashmap.h" +#include "log.h" +#include "machine-image.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-util.h" +#include "pretty-print.h" +#include "process-util.h" +#include "sort-util.h" +#include "stat-util.h" +#include "terminal-util.h" +#include "user-util.h" + +static enum { + ACTION_STATUS, + ACTION_MERGE, + ACTION_UNMERGE, + ACTION_REFRESH, + ACTION_LIST, +} arg_action = ACTION_STATUS; +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_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_dev(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; + char **p; + + 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 status(void) { + _cleanup_(table_unrefp) Table *t = NULL; + int r, ret = 0; + char **p; + + t = table_new("hierarchy", "extensions", "since"); + if (!t) + return log_oom(); + + (void) table_set_empty_string(t, "-"); + + 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, (size_t) -1); + + if (arg_json_format_flags & (JSON_FORMAT_OFF|JSON_FORMAT_PRETTY|JSON_FORMAT_PRETTY_AUTO)) + (void) pager_open(arg_pager_flags); + + r = table_print_json(t, stdout, arg_json_format_flags); + if (r < 0) + return table_log_add_error(r); + + return ret; +} + +static int mount_overlayfs( + const char *where, + char **layers) { + + _cleanup_free_ char *options = NULL; + bool separator = false; + char **l; + 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; + char **p; + 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); + 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); + 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 strverscmpp(char *const* a, char *const* b) { + /* usable in qsort() for sorting a string array with strverscmp() */ + return strverscmp(*a, *b); +} + +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; + char **h; + 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, "sysexit", 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, + NULL); + if (r < 0) + return log_error_errno(r, "Failed to acquire '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, + *extension_os_release_id = NULL, *extension_os_release_version_id = NULL, *extension_os_release_sysext_level = 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_(decrypted_image_unrefp) DecryptedImage *di = NULL; + DissectImageFlags flags = DISSECT_IMAGE_READ_ONLY|DISSECT_IMAGE_REQUIRE_ROOT|DISSECT_IMAGE_MOUNT_ROOT_ONLY; + + r = loop_device_make_by_path(img->path, O_RDONLY, 0, &d); + if (r < 0) + return log_error_errno(r, "Failed to set up loopback device: %m"); + + r = dissect_image_and_warn( + d->fd, + img->path, + NULL, + NULL, + flags, + &m); + if (r < 0) + return r; + + r = dissected_image_decrypt_interactively( + m, NULL, + NULL, + flags, + &di); + if (r < 0) + return r; + + r = dissected_image_mount_and_warn( + m, + p, + UID_INVALID, + flags); + if (r < 0) + return r; + + if (di) { + r = decrypted_image_relinquish(di); + if (r < 0) + return log_error_errno(r, "Failed to relinquish DM devices: %m"); + } + + loop_device_relinquish(d); + break; + } + default: + assert_not_reached("Unsupported image type"); + } + + /* 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", p, 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."); + + /* Now that we can look into the extension image, let's see if the OS version is compatible */ + r = parse_os_release( + p, + "ID", &extension_os_release_id, + "VERSION_ID", &extension_os_release_version_id, + "SYSEXT_LEVEL", &extension_os_release_sysext_level, + NULL); + if (r == -ENOENT) + log_notice_errno(r, "Extension '%s' carries no os-release data, not checking for version compatibility.", img->name); + else if (r < 0) + return log_error_errno(r, "Failed to acquire 'os-release' data of extension '%s': %m", img->name); + else { + if (!streq_ptr(host_os_release_id, extension_os_release_id)) { + log_notice("Extension '%s' is for OS '%s', but running on '%s', ignoring extension.", + img->name, strna(extension_os_release_id), strna(host_os_release_id)); + n_ignored++; + continue; + } + + /* If the extension has a sysext API level declared, then it must match the host API level. Otherwise, compare OS version as a whole */ + if (extension_os_release_sysext_level) { + if (!streq_ptr(host_os_release_sysext_level, extension_os_release_sysext_level)) { + log_notice("Extension '%s' is for sysext API level '%s', but running on sysext API level '%s', ignoring extension.", + img->name, extension_os_release_sysext_level, strna(host_os_release_sysext_level)); + n_ignored++; + continue; + } + } else { + if (!streq_ptr(host_os_release_version_id, extension_os_release_version_id)) { + log_notice("Extension '%s' is for OS version '%s', but running on OS version '%s', ignoring extension.", + img->name, extension_os_release_version_id, strna(host_os_release_version_id)); + n_ignored++; + continue; + } + } + + log_debug("Version info of extension '%s' matches host.", img->name); + } + + /* Noice! 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 (i.e. libc strverscmp()) */ + typesafe_qsort(extensions, n_extensions, strverscmpp); + + 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 help(void) { + _cleanup_free_ char *link = NULL; + int r; + + r = terminal_urlify_man("systemd-sysext", "1", &link); + if (r < 0) + return log_oom(); + + printf("%1$s [OPTIONS...] [DEVICE]\n" + "\n%5$sMerge extension images into /usr/ and /opt/ hierarchies.%6$s\n" + "\n%3$sCommands:%4$s\n" + " -h --help Show this help\n" + " --version Show package version\n" + " -m --merge Merge extensions into /usr/ and /opt/\n" + " -u --unmerge Unmerge extensions from /usr/ and /opt/\n" + " -R --refresh Unmerge/merge extensions again\n" + " -l --list List all OS images\n" + "\n%3$sOptions:%4$s\n" + " --no-pager Do not pipe output into a pager\n" + " --root=PATH Operate relative to root path\n" + " --json=pretty|short|off\n" + " Generate JSON output\n" + "\nSee the %2$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_MERGE, + ARG_UNMERGE, + ARG_REFRESH, + ARG_LIST, + ARG_ROOT, + ARG_JSON, + }; + + static const struct option options[] = { + { "help", no_argument, NULL, 'h' }, + { "version", no_argument, NULL, ARG_VERSION }, + { "no-pager", no_argument, NULL, ARG_NO_PAGER }, + { "root", required_argument, NULL, ARG_ROOT }, + { "merge", no_argument, NULL, 'm' }, + { "unmerge", no_argument, NULL, 'u' }, + { "refresh", no_argument, NULL, 'R' }, + { "list", no_argument, NULL, 'l' }, + { "json", required_argument, NULL, ARG_JSON }, + {} + }; + + int c, r; + + assert(argc >= 0); + assert(argv); + + while ((c = getopt_long(argc, argv, "hmuRl", options, NULL)) >= 0) + + switch (c) { + + case 'h': + return help(); + + case ARG_VERSION: + return version(); + + case ARG_NO_PAGER: + arg_pager_flags |= PAGER_DISABLE; + break; + + case 'm': + arg_action = ACTION_MERGE; + break; + + case 'u': + arg_action = ACTION_UNMERGE; + break; + + case 'R': + arg_action = ACTION_REFRESH; + break; + + case 'l': + arg_action = ACTION_LIST; + break; + + case ARG_ROOT: + r = parse_path_argument_and_warn(optarg, false, &arg_root); + if (r < 0) + return r; + break; + + case ARG_JSON: + r = json_parse_cmdline_parameter_and_warn(optarg, &arg_json_format_flags); + if (r <= 0) + return r; + + break; + + case '?': + return -EINVAL; + + default: + assert_not_reached("Unhandled option"); + } + + if (argc - optind > 0) + return log_error_errno(SYNTHETIC_ERRNO(EINVAL), + "Unexpected argument."); + + return 1; +} + +static int parse_env(void) { + _cleanup_strv_free_ char **l = NULL; + const char *e; + char **p; + int r; + + e = secure_getenv("SYSTEMD_SYSEXT_HIERARCHIES"); + if (!e) + return 0; + + /* 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 = strv_split_full(&l, e, ":", EXTRACT_DONT_COALESCE_SEPARATORS); + if (r < 0) + return log_error_errno(r, "Failed to parse $SYSTEMD_SYSEXT_HIERARCHIES: %m"); + + STRV_FOREACH(p, l) { + if (!path_is_absolute(*p)) + return log_error_errno(SYNTHETIC_ERRNO(EINVAL), + "Hierarchy path '%s' is not absolute, refusing.", *p); + + if (!path_is_normalized(*p)) + return log_error_errno(SYNTHETIC_ERRNO(EINVAL), + "Hierarchy path '%s' is not normalized, refusing.", *p); + + if (path_equal(*p, "/")) + return log_error_errno(SYNTHETIC_ERRNO(EINVAL), + "Hierarchy path '%s' is the root fs, refusing.", *p); + } + + if (strv_isempty(l)) + return log_error_errno(SYNTHETIC_ERRNO(EINVAL), + "No hierarchies specified, refusing."); + + strv_free_and_replace(arg_hierarchies, l); + return 0; +} + +static int run(int argc, char *argv[]) { + _cleanup_(hashmap_freep) Hashmap *images = NULL; + int r; + + log_show_color(true); + log_parse_environment(); + log_open(); + + r = parse_argv(argc, argv); + if (r <= 0) + return r; + + r = parse_env(); + if (r < 0) + return r; + + if (!arg_hierarchies) { + arg_hierarchies = strv_new("/usr", "/opt"); + if (!arg_hierarchies) + return log_oom(); + } + + /* Given that things deep down in the child process will fail, let's catch the no-privilege issue + * early on */ + if (!IN_SET(arg_action, ACTION_STATUS, ACTION_LIST) && !have_effective_cap(CAP_SYS_ADMIN)) + return log_error_errno(SYNTHETIC_ERRNO(EPERM), "Need to be privileged."); + + if (arg_action == ACTION_STATUS) + return status(); + + if (arg_action == ACTION_UNMERGE) + return unmerge(); + + images = hashmap_new(&image_hash_ops); + if (!images) + return log_oom(); + + r = image_discover(IMAGE_EXTENSION, images); + if (r < 0) + return log_error_errno(r, "Failed to discover extension images: %m"); + + switch (arg_action) { + + case ACTION_LIST: { + _cleanup_(table_unrefp) Table *t = NULL; + Image *img; + + 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, (size_t) -1); + + if (arg_json_format_flags & (JSON_FORMAT_OFF|JSON_FORMAT_PRETTY|JSON_FORMAT_PRETTY_AUTO)) + (void) pager_open(arg_pager_flags); + + r = table_print_json(t, stdout, arg_json_format_flags); + if (r < 0) + return table_log_print_error(r); + + r = 0; + break; + } + + case ACTION_MERGE: { + char **p; + + /* 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); + } + + r = merge(images); + break; + } + + case ACTION_REFRESH: + 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. + */ + break; + + default: + assert_not_reached("Uneexpected action"); + } + + return r; +} + +DEFINE_MAIN_FUNCTION(run);