| /* SPDX-License-Identifier: LGPL-2.1-or-later */ |
| |
| #include "sd-id128.h" |
| |
| #include "dirent-util.h" |
| #include "fd-util.h" |
| #include "fs-util.h" |
| #include "macro.h" |
| #include "path-lookup.h" |
| #include "set.h" |
| #include "special.h" |
| #include "stat-util.h" |
| #include "string-util.h" |
| #include "strv.h" |
| #include "unit-file.h" |
| |
| bool unit_type_may_alias(UnitType type) { |
| return IN_SET(type, |
| UNIT_SERVICE, |
| UNIT_SOCKET, |
| UNIT_TARGET, |
| UNIT_DEVICE, |
| UNIT_TIMER, |
| UNIT_PATH); |
| } |
| |
| bool unit_type_may_template(UnitType type) { |
| return IN_SET(type, |
| UNIT_SERVICE, |
| UNIT_SOCKET, |
| UNIT_TARGET, |
| UNIT_TIMER, |
| UNIT_PATH); |
| } |
| |
| int unit_symlink_name_compatible(const char *symlink, const char *target, bool instance_propagation) { |
| _cleanup_free_ char *template = NULL; |
| int r, un_type1, un_type2; |
| |
| un_type1 = unit_name_classify(symlink); |
| |
| /* The straightforward case: the symlink name matches the target and we have a valid unit */ |
| if (streq(symlink, target) && |
| (un_type1 & (UNIT_NAME_PLAIN | UNIT_NAME_INSTANCE))) |
| return 1; |
| |
| r = unit_name_template(symlink, &template); |
| if (r == -EINVAL) |
| return 0; /* Not a template */ |
| if (r < 0) |
| return r; |
| |
| un_type2 = unit_name_classify(target); |
| |
| /* An instance name points to a target that is just the template name */ |
| if (un_type1 == UNIT_NAME_INSTANCE && |
| un_type2 == UNIT_NAME_TEMPLATE && |
| streq(template, target)) |
| return 1; |
| |
| /* foo@.target.requires/bar@.service: instance will be propagated */ |
| if (instance_propagation && |
| un_type1 == UNIT_NAME_TEMPLATE && |
| un_type2 == UNIT_NAME_TEMPLATE && |
| streq(template, target)) |
| return 1; |
| |
| return 0; |
| } |
| |
| int unit_validate_alias_symlink_and_warn(const char *filename, const char *target) { |
| const char *src, *dst; |
| _cleanup_free_ char *src_instance = NULL, *dst_instance = NULL; |
| UnitType src_unit_type, dst_unit_type; |
| UnitNameFlags src_name_type, dst_name_type; |
| |
| /* Check if the *alias* symlink is valid. This applies to symlinks like |
| * /etc/systemd/system/dbus.service → dbus-broker.service, but not to .wants or .requires symlinks |
| * and such. Neither does this apply to symlinks which *link* units, i.e. symlinks to outside of the |
| * unit lookup path. |
| * |
| * -EINVAL is returned if the something is wrong with the source filename or the source unit type is |
| * not allowed to symlink, |
| * -EXDEV if the target filename is not a valid unit name or doesn't match the source. |
| */ |
| |
| src = basename(filename); |
| dst = basename(target); |
| |
| /* src checks */ |
| |
| src_name_type = unit_name_to_instance(src, &src_instance); |
| if (src_name_type < 0) |
| return log_notice_errno(src_name_type, |
| "%s: not a valid unit name \"%s\": %m", filename, src); |
| |
| src_unit_type = unit_name_to_type(src); |
| assert(src_unit_type >= 0); /* unit_name_to_instance() checked the suffix already */ |
| |
| if (!unit_type_may_alias(src_unit_type)) |
| return log_notice_errno(SYNTHETIC_ERRNO(EINVAL), |
| "%s: symlinks are not allowed for units of this type, rejecting.", |
| filename); |
| |
| if (src_name_type != UNIT_NAME_PLAIN && |
| !unit_type_may_template(src_unit_type)) |
| return log_notice_errno(SYNTHETIC_ERRNO(EINVAL), |
| "%s: templates not allowed for %s units, rejecting.", |
| filename, unit_type_to_string(src_unit_type)); |
| |
| /* dst checks */ |
| |
| dst_name_type = unit_name_to_instance(dst, &dst_instance); |
| if (dst_name_type < 0) |
| return log_notice_errno(dst_name_type == -EINVAL ? SYNTHETIC_ERRNO(EXDEV) : dst_name_type, |
| "%s points to \"%s\" which is not a valid unit name: %m", |
| filename, dst); |
| |
| if (!(dst_name_type == src_name_type || |
| (src_name_type == UNIT_NAME_INSTANCE && dst_name_type == UNIT_NAME_TEMPLATE))) |
| return log_notice_errno(SYNTHETIC_ERRNO(EXDEV), |
| "%s: symlink target name type \"%s\" does not match source, rejecting.", |
| filename, dst); |
| |
| if (dst_name_type == UNIT_NAME_INSTANCE) { |
| assert(src_instance); |
| assert(dst_instance); |
| if (!streq(src_instance, dst_instance)) |
| return log_notice_errno(SYNTHETIC_ERRNO(EXDEV), |
| "%s: unit symlink target \"%s\" instance name doesn't match, rejecting.", |
| filename, dst); |
| } |
| |
| dst_unit_type = unit_name_to_type(dst); |
| if (dst_unit_type != src_unit_type) |
| return log_notice_errno(SYNTHETIC_ERRNO(EXDEV), |
| "%s: symlink target \"%s\" has incompatible suffix, rejecting.", |
| filename, dst); |
| |
| return 0; |
| } |
| |
| #define FOLLOW_MAX 8 |
| |
| static int unit_ids_map_get( |
| Hashmap *unit_ids_map, |
| const char *unit_name, |
| const char **ret_fragment_path) { |
| |
| /* Resolve recursively until we hit an absolute path, i.e. a non-aliased unit. |
| * |
| * We distinguish the case where unit_name was not found in the hashmap at all, and the case where |
| * some symlink was broken. |
| * |
| * If a symlink target points to an instance name, then we also check for the template. */ |
| |
| const char *id = NULL; |
| int r; |
| |
| for (unsigned n = 0; n < FOLLOW_MAX; n++) { |
| const char *t = hashmap_get(unit_ids_map, id ?: unit_name); |
| if (!t) { |
| _cleanup_free_ char *template = NULL; |
| |
| if (!id) |
| return -ENOENT; |
| |
| r = unit_name_template(id, &template); |
| if (r == -EINVAL) |
| return -ENXIO; /* we failed to find the symlink target */ |
| if (r < 0) |
| return log_error_errno(r, "Failed to determine template name for %s: %m", id); |
| |
| t = hashmap_get(unit_ids_map, template); |
| if (!t) |
| return -ENXIO; |
| |
| /* We successfully switched from instanced name to a template, let's continue */ |
| } |
| |
| if (path_is_absolute(t)) { |
| if (ret_fragment_path) |
| *ret_fragment_path = t; |
| return 0; |
| } |
| |
| id = t; |
| } |
| |
| return -ELOOP; |
| } |
| |
| static bool lookup_paths_mtime_exclude(const LookupPaths *lp, const char *path) { |
| /* Paths that are under our exclusive control. Users shall not alter those directly. */ |
| |
| return streq_ptr(path, lp->generator) || |
| streq_ptr(path, lp->generator_early) || |
| streq_ptr(path, lp->generator_late) || |
| streq_ptr(path, lp->transient) || |
| streq_ptr(path, lp->persistent_control) || |
| streq_ptr(path, lp->runtime_control); |
| } |
| |
| #define HASH_KEY SD_ID128_MAKE(4e,86,1b,e3,39,b3,40,46,98,5d,b8,11,34,8f,c3,c1) |
| |
| bool lookup_paths_timestamp_hash_same(const LookupPaths *lp, uint64_t timestamp_hash, uint64_t *ret_new) { |
| struct siphash state; |
| |
| siphash24_init(&state, HASH_KEY.bytes); |
| |
| char **dir; |
| STRV_FOREACH(dir, (char**) lp->search_path) { |
| struct stat st; |
| |
| if (lookup_paths_mtime_exclude(lp, *dir)) |
| continue; |
| |
| /* Determine the latest lookup path modification time */ |
| if (stat(*dir, &st) < 0) { |
| if (errno == ENOENT) |
| continue; |
| |
| log_debug_errno(errno, "Failed to stat %s, ignoring: %m", *dir); |
| continue; |
| } |
| |
| siphash24_compress_usec_t(timespec_load(&st.st_mtim), &state); |
| } |
| |
| uint64_t updated = siphash24_finalize(&state); |
| if (ret_new) |
| *ret_new = updated; |
| if (updated != timestamp_hash) |
| log_debug("Modification times have changed, need to update cache."); |
| return updated == timestamp_hash; |
| } |
| |
| int unit_file_build_name_map( |
| const LookupPaths *lp, |
| uint64_t *cache_timestamp_hash, |
| Hashmap **unit_ids_map, |
| Hashmap **unit_names_map, |
| Set **path_cache) { |
| |
| /* Build two mappings: any name → main unit (i.e. the end result of symlink resolution), unit name → |
| * all aliases (i.e. the entry for a given key is a list of all names which point to this key). The |
| * key is included in the value iff we saw a file or symlink with that name. In other words, if we |
| * have a key, but it is not present in the value for itself, there was an alias pointing to it, but |
| * the unit itself is not loadable. |
| * |
| * At the same, build a cache of paths where to find units. The non-const parameters are for input |
| * and output. Existing contents will be freed before the new contents are stored. |
| */ |
| |
| _cleanup_hashmap_free_ Hashmap *ids = NULL, *names = NULL; |
| _cleanup_set_free_free_ Set *paths = NULL; |
| uint64_t timestamp_hash; |
| char **dir; |
| int r; |
| |
| /* Before doing anything, check if the timestamp hash that was passed is still valid. |
| * If yes, do nothing. */ |
| if (cache_timestamp_hash && |
| lookup_paths_timestamp_hash_same(lp, *cache_timestamp_hash, ×tamp_hash)) |
| return 0; |
| |
| /* The timestamp hash is now set based on the mtimes from before when we start reading files. |
| * If anything is modified concurrently, we'll consider the cache outdated. */ |
| |
| if (path_cache) { |
| paths = set_new(&path_hash_ops_free); |
| if (!paths) |
| return log_oom(); |
| } |
| |
| STRV_FOREACH(dir, (char**) lp->search_path) { |
| struct dirent *de; |
| _cleanup_closedir_ DIR *d = NULL; |
| |
| d = opendir(*dir); |
| if (!d) { |
| if (errno != ENOENT) |
| log_warning_errno(errno, "Failed to open \"%s\", ignoring: %m", *dir); |
| continue; |
| } |
| |
| FOREACH_DIRENT_ALL(de, d, log_warning_errno(errno, "Failed to read \"%s\", ignoring: %m", *dir)) { |
| char *filename; |
| _unused_ _cleanup_free_ char *_filename_free = NULL; |
| _cleanup_free_ char *simplified = NULL; |
| const char *suffix, *dst = NULL; |
| bool valid_unit_name; |
| |
| valid_unit_name = unit_name_is_valid(de->d_name, UNIT_NAME_ANY); |
| |
| /* We only care about valid units and dirs with certain suffixes, let's ignore the |
| * rest. */ |
| if (!valid_unit_name && |
| !ENDSWITH_SET(de->d_name, ".wants", ".requires", ".d")) |
| continue; |
| |
| filename = path_join(*dir, de->d_name); |
| if (!filename) |
| return log_oom(); |
| |
| if (paths) { |
| r = set_put(paths, filename); |
| if (r < 0) |
| return log_oom(); |
| if (r == 0) |
| _filename_free = filename; /* Make sure we free the filename. */ |
| } else |
| _filename_free = filename; /* Make sure we free the filename. */ |
| |
| if (!valid_unit_name) |
| continue; |
| assert_se(suffix = strrchr(de->d_name, '.')); |
| |
| /* search_path is ordered by priority (highest first). If the name is already mapped |
| * to something (incl. itself), it means that we have already seen it, and we should |
| * ignore it here. */ |
| if (hashmap_contains(ids, de->d_name)) |
| continue; |
| |
| if (de->d_type == DT_LNK) { |
| /* We don't explicitly check for alias loops here. unit_ids_map_get() which |
| * limits the number of hops should be used to access the map. */ |
| |
| _cleanup_free_ char *target = NULL; |
| |
| r = readlinkat_malloc(dirfd(d), de->d_name, &target); |
| if (r < 0) { |
| log_warning_errno(r, "Failed to read symlink %s/%s, ignoring: %m", |
| *dir, de->d_name); |
| continue; |
| } |
| |
| const bool is_abs = path_is_absolute(target); |
| if (lp->root_dir || !is_abs) { |
| char *target_abs = path_join(is_abs ? lp->root_dir : *dir, target); |
| if (!target_abs) |
| return log_oom(); |
| |
| free_and_replace(target, target_abs); |
| } |
| |
| /* Get rid of "." and ".." components in target path */ |
| r = chase_symlinks(target, lp->root_dir, CHASE_NOFOLLOW | CHASE_NONEXISTENT, &simplified, NULL); |
| if (r < 0) { |
| log_warning_errno(r, "Failed to resolve symlink %s pointing to %s, ignoring: %m", |
| filename, target); |
| continue; |
| } |
| |
| /* Check if the symlink goes outside of our search path. |
| * If yes, it's a linked unit file or mask, and we don't care about the target name. |
| * Let's just store the link source directly. |
| * If not, let's verify that it's a good symlink. */ |
| char *tail = path_startswith_strv(simplified, lp->search_path); |
| if (!tail) { |
| log_debug("%s: linked unit file: %s → %s", |
| __func__, filename, simplified); |
| |
| dst = filename; |
| } else { |
| |
| bool self_alias; |
| |
| dst = basename(simplified); |
| self_alias = streq(dst, de->d_name); |
| |
| if (is_path(tail)) |
| log_full(self_alias ? LOG_DEBUG : LOG_WARNING, |
| "Suspicious symlink %s→%s, treating as alias.", |
| filename, simplified); |
| |
| r = unit_validate_alias_symlink_and_warn(filename, simplified); |
| if (r < 0) |
| continue; |
| |
| if (self_alias) { |
| /* A self-alias that has no effect */ |
| log_debug("%s: self-alias: %s/%s → %s, ignoring.", |
| __func__, *dir, de->d_name, dst); |
| continue; |
| } |
| |
| log_debug("%s: alias: %s/%s → %s", __func__, *dir, de->d_name, dst); |
| } |
| |
| } else { |
| dst = filename; |
| log_debug("%s: normal unit file: %s", __func__, dst); |
| } |
| |
| r = hashmap_put_strdup(&ids, de->d_name, dst); |
| if (r < 0) |
| return log_warning_errno(r, "Failed to add entry to hashmap (%s→%s): %m", |
| de->d_name, dst); |
| } |
| } |
| |
| /* Let's also put the names in the reverse db. */ |
| const char *dummy, *src; |
| HASHMAP_FOREACH_KEY(dummy, src, ids) { |
| _cleanup_free_ char *inst = NULL, *dst_inst = NULL; |
| const char *dst; |
| |
| r = unit_ids_map_get(ids, src, &dst); |
| if (r < 0) |
| continue; |
| |
| if (null_or_empty_path(dst) != 0) |
| continue; |
| |
| dst = basename(dst); |
| |
| /* If we have an symlink from an instance name to a template name, it is an alias just for |
| * this specific instance, foo@id.service ↔ template@id.service. */ |
| if (unit_name_is_valid(dst, UNIT_NAME_TEMPLATE)) { |
| UnitNameFlags t = unit_name_to_instance(src, &inst); |
| if (t < 0) |
| return log_error_errno(t, "Failed to extract instance part from %s: %m", src); |
| if (t == UNIT_NAME_INSTANCE) { |
| r = unit_name_replace_instance(dst, inst, &dst_inst); |
| if (r < 0) { |
| /* This might happen e.g. if the combined length is too large. |
| * Let's not make too much of a fuss. */ |
| log_debug_errno(r, "Failed to build alias name (%s + %s), ignoring: %m", |
| dst, inst); |
| continue; |
| } |
| |
| dst = dst_inst; |
| } |
| } |
| |
| r = string_strv_hashmap_put(&names, dst, src); |
| if (r < 0) |
| return log_warning_errno(r, "Failed to add entry to hashmap (%s→%s): %m", dst, src); |
| } |
| |
| if (cache_timestamp_hash) |
| *cache_timestamp_hash = timestamp_hash; |
| |
| hashmap_free_and_replace(*unit_ids_map, ids); |
| hashmap_free_and_replace(*unit_names_map, names); |
| if (path_cache) |
| set_free_and_replace(*path_cache, paths); |
| |
| return 1; |
| } |
| |
| static int add_name( |
| const char *unit_name, |
| Set **names, |
| const char *name) { |
| int r; |
| |
| assert(names); |
| assert(name); |
| |
| r = set_put_strdup(names, name); |
| if (r < 0) |
| return r; |
| if (r > 0 && !streq(unit_name, name)) |
| log_debug("Unit %s has alias %s.", unit_name, name); |
| return r; |
| } |
| |
| static int add_names( |
| Hashmap *unit_ids_map, |
| Hashmap *unit_name_map, |
| const char *unit_name, |
| const char *fragment_basename, /* Only set when adding additional names based on fragment path */ |
| UnitNameFlags name_type, |
| const char *instance, |
| Set **names, |
| const char *name) { |
| |
| char **aliases, **alias; |
| int r; |
| |
| assert(name_type == UNIT_NAME_PLAIN || instance); |
| |
| /* The unit has its own name if it's not a template. If we're looking at a fragment, the fragment |
| * name (possibly with instance inserted), is also always one of the unit names. */ |
| if (name_type != UNIT_NAME_TEMPLATE) { |
| r = add_name(unit_name, names, name); |
| if (r < 0) |
| return r; |
| } |
| |
| /* Add any aliases of the name to the set of names. |
| * |
| * We don't even need to know which fragment we will use. The unit_name_map should return the same |
| * set of names for any of the aliases. */ |
| aliases = hashmap_get(unit_name_map, name); |
| STRV_FOREACH(alias, aliases) { |
| if (name_type == UNIT_NAME_INSTANCE && unit_name_is_valid(*alias, UNIT_NAME_TEMPLATE)) { |
| _cleanup_free_ char *inst = NULL; |
| const char *inst_fragment = NULL; |
| |
| r = unit_name_replace_instance(*alias, instance, &inst); |
| if (r < 0) |
| return log_debug_errno(r, "Cannot build instance name %s + %s: %m", |
| *alias, instance); |
| |
| /* Exclude any aliases that point in some other direction. |
| * |
| * See https://github.com/systemd/systemd/pull/13119#discussion_r308145418. */ |
| r = unit_ids_map_get(unit_ids_map, inst, &inst_fragment); |
| if (r < 0 && !IN_SET(r, -ENOENT, -ENXIO)) |
| return log_debug_errno(r, "Cannot find instance fragment %s: %m", inst); |
| |
| if (inst_fragment && |
| !streq(basename(inst_fragment), fragment_basename)) { |
| log_debug("Instance %s has fragment %s and is not an alias of %s.", |
| inst, inst_fragment, unit_name); |
| continue; |
| } |
| |
| r = set_consume(*names, TAKE_PTR(inst)); |
| if (r > 0) |
| log_debug("Unit %s has alias %s.", unit_name, inst); |
| } else |
| r = add_name(unit_name, names, *alias); |
| |
| if (r < 0) |
| return r; |
| } |
| |
| return 0; |
| } |
| |
| int unit_file_find_fragment( |
| Hashmap *unit_ids_map, |
| Hashmap *unit_name_map, |
| const char *unit_name, |
| const char **ret_fragment_path, |
| Set **ret_names) { |
| |
| const char *fragment = NULL; |
| _cleanup_free_ char *template = NULL, *instance = NULL; |
| _cleanup_set_free_ Set *names = NULL; |
| int r; |
| |
| /* Finds a fragment path, and returns the set of names: |
| * if we have …/foo.service and …/foo-alias.service→foo.service, |
| * and …/foo@.service and …/foo-alias@.service→foo@.service, |
| * and …/foo@inst.service, |
| * this should return: |
| * foo.service → …/foo.service, {foo.service, foo-alias.service}, |
| * foo-alias.service → …/foo.service, {foo.service, foo-alias.service}, |
| * foo@.service → …/foo@.service, {foo@.service, foo-alias@.service}, |
| * foo-alias@.service → …/foo@.service, {foo@.service, foo-alias@.service}, |
| * foo@bar.service → …/foo@.service, {foo@bar.service, foo-alias@bar.service}, |
| * foo-alias@bar.service → …/foo@.service, {foo@bar.service, foo-alias@bar.service}, |
| * foo-alias@inst.service → …/foo@inst.service, {foo@inst.service, foo-alias@inst.service}. |
| */ |
| |
| UnitNameFlags name_type = unit_name_to_instance(unit_name, &instance); |
| if (name_type < 0) |
| return name_type; |
| |
| r = add_names(unit_ids_map, unit_name_map, unit_name, NULL, name_type, instance, &names, unit_name); |
| if (r < 0) |
| return r; |
| |
| /* First try to load fragment under the original name */ |
| r = unit_ids_map_get(unit_ids_map, unit_name, &fragment); |
| if (r < 0 && !IN_SET(r, -ENOENT, -ENXIO)) |
| return log_debug_errno(r, "Cannot load unit %s: %m", unit_name); |
| |
| if (!fragment && name_type == UNIT_NAME_INSTANCE) { |
| /* Look for a fragment under the template name */ |
| |
| r = unit_name_template(unit_name, &template); |
| if (r < 0) |
| return log_debug_errno(r, "Failed to determine template name: %m"); |
| |
| r = unit_ids_map_get(unit_ids_map, template, &fragment); |
| if (r < 0 && !IN_SET(r, -ENOENT, -ENXIO)) |
| return log_debug_errno(r, "Cannot load template %s: %m", template); |
| } |
| |
| if (fragment) { |
| const char *fragment_basename = basename(fragment); |
| |
| if (!streq(fragment_basename, unit_name)) { |
| /* Add names based on the fragment name to the set of names */ |
| r = add_names(unit_ids_map, unit_name_map, unit_name, fragment_basename, name_type, instance, &names, fragment_basename); |
| if (r < 0) |
| return r; |
| } |
| } |
| |
| *ret_fragment_path = fragment; |
| *ret_names = TAKE_PTR(names); |
| |
| return 0; |
| } |
| |
| static const char * const rlmap[] = { |
| "emergency", SPECIAL_EMERGENCY_TARGET, |
| "-b", SPECIAL_EMERGENCY_TARGET, |
| "rescue", SPECIAL_RESCUE_TARGET, |
| "single", SPECIAL_RESCUE_TARGET, |
| "-s", SPECIAL_RESCUE_TARGET, |
| "s", SPECIAL_RESCUE_TARGET, |
| "S", SPECIAL_RESCUE_TARGET, |
| "1", SPECIAL_RESCUE_TARGET, |
| "2", SPECIAL_MULTI_USER_TARGET, |
| "3", SPECIAL_MULTI_USER_TARGET, |
| "4", SPECIAL_MULTI_USER_TARGET, |
| "5", SPECIAL_GRAPHICAL_TARGET, |
| NULL |
| }; |
| |
| static const char * const rlmap_initrd[] = { |
| "emergency", SPECIAL_EMERGENCY_TARGET, |
| "rescue", SPECIAL_RESCUE_TARGET, |
| NULL |
| }; |
| |
| const char* runlevel_to_target(const char *word) { |
| const char * const *rlmap_ptr; |
| |
| if (!word) |
| return NULL; |
| |
| if (in_initrd()) { |
| word = startswith(word, "rd."); |
| if (!word) |
| return NULL; |
| } |
| |
| rlmap_ptr = in_initrd() ? rlmap_initrd : rlmap; |
| |
| for (size_t i = 0; rlmap_ptr[i]; i += 2) |
| if (streq(word, rlmap_ptr[i])) |
| return rlmap_ptr[i+1]; |
| |
| return NULL; |
| } |
