/* SPDX-License-Identifier: LGPL-2.1+ */
+#include "dirent-util.h"
+#include "fd-util.h"
+#include "fs-util.h"
#include "macro.h"
+#include "path-lookup.h"
+#include "set.h"
+#include "stat-util.h"
#include "string-util.h"
+#include "strv.h"
#include "unit-file.h"
bool unit_type_may_alias(UnitType type) {
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;
+}
+
+int unit_file_build_name_map(
+ const LookupPaths *lp,
+ Hashmap **ret_unit_ids_map,
+ Hashmap **ret_unit_names_map,
+ Set **ret_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 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.
+ */
+
+ _cleanup_hashmap_free_ Hashmap *ids = NULL, *names = NULL;
+ _cleanup_set_free_free_ Set *paths = NULL;
+ char **dir;
+ int r;
+
+ if (ret_path_cache) {
+ paths = set_new(&path_hash_ops);
+ 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(de, d, log_warning_errno(errno, "Failed to read \"%s\", ignoring: %m", *dir)) {
+ char *filename;
+ _cleanup_free_ char *_filename_free = NULL, *simplified = NULL;
+ const char *suffix, *dst = NULL;
+
+ filename = path_join(*dir, de->d_name);
+ if (!filename)
+ return log_oom();
+
+ if (ret_path_cache) {
+ r = set_consume(paths, filename);
+ if (r < 0)
+ return log_oom();
+ /* We will still use filename below. This is safe because we know the set
+ * holds a reference. */
+ } else
+ _filename_free = filename; /* Make sure we free the filename. */
+
+ if (!unit_name_is_valid(de->d_name, UNIT_NAME_ANY))
+ 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, *target_abs = 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;
+ }
+
+ if (!path_is_absolute(target)) {
+ target_abs = path_join(*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);
+ 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 destination directly.
+ * If not, let's verify that it's a good symlink. */
+ char *tail = path_startswith_strv(simplified, lp->search_path);
+ if (tail) {
+ 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 = simplified;
+
+ log_debug("%s: linked unit file: %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. */
+ Iterator it;
+ const char *dummy, *src;
+ HASHMAP_FOREACH_KEY(dummy, src, ids, it) {
+ const char *dst;
+
+ r = unit_ids_map_get(ids, src, &dst);
+ if (r < 0)
+ continue;
+
+ if (null_or_empty_path(dst) != 0)
+ continue;
+
+ /* Do not treat instance symlinks that point to the template as aliases */
+ if (unit_name_is_valid(basename(dst), UNIT_NAME_TEMPLATE) &&
+ unit_name_is_valid(src, UNIT_NAME_INSTANCE))
+ continue;
+
+ r = string_strv_hashmap_put(&names, basename(dst), src);
+ if (r < 0)
+ return log_warning_errno(r, "Failed to add entry to hashmap (%s→%s): %m",
+ basename(dst), src);
+ }
+
+ *ret_unit_ids_map = TAKE_PTR(ids);
+ *ret_unit_names_map = TAKE_PTR(names);
+ if (ret_path_cache)
+ *ret_path_cache = TAKE_PTR(paths);
+
+ 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_free_ Set *names = NULL;
+ char **t, **nnn;
+ int r, name_type;
+
+ /* 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}.
+ */
+
+ name_type = unit_name_to_instance(unit_name, &instance);
+ if (name_type < 0)
+ return name_type;
+
+ names = set_new(&string_hash_ops);
+ if (!names)
+ return -ENOMEM;
+
+ /* The unit always has its own name if it's not a template. */
+ if (unit_name_is_valid(unit_name, UNIT_NAME_PLAIN | UNIT_NAME_INSTANCE)) {
+ r = set_put_strdup(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) {
+ /* Add any aliases of the original name to the set of names */
+ nnn = hashmap_get(unit_name_map, basename(fragment));
+ STRV_FOREACH(t, nnn) {
+ if (instance && unit_name_is_valid(*t, UNIT_NAME_TEMPLATE)) {
+ char *inst;
+
+ r = unit_name_replace_instance(*t, instance, &inst);
+ if (r < 0)
+ return log_debug_errno(r, "Cannot build instance name %s+%s: %m", *t, instance);
+
+ if (!streq(unit_name, inst))
+ log_debug("%s: %s has alias %s", __func__, unit_name, inst);
+
+ log_info("%s: %s+%s → %s", __func__, *t, instance, inst);
+ r = set_consume(names, inst);
+ } else {
+ if (!streq(unit_name, *t))
+ log_debug("%s: %s has alias %s", __func__, unit_name, *t);
+
+ r = set_put_strdup(names, *t);
+ }
+ if (r < 0)
+ return r;
+ }
+ }
+
+ 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_error_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", *t);
+
+ if (fragment) {
+ /* Add any aliases of the original name to the set of names */
+ nnn = hashmap_get(unit_name_map, basename(fragment));
+ STRV_FOREACH(t, nnn) {
+ _cleanup_free_ char *inst = NULL;
+ const char *inst_fragment = NULL;
+
+ r = unit_name_replace_instance(*t, instance, &inst);
+ if (r < 0)
+ return log_debug_errno(r, "Cannot build instance name %s+%s: %m", template, instance);
+
+ /* Exclude any aliases that point in some other direction. */
+ 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), basename(fragment))) {
+ log_debug("Instance %s has fragment %s and is not an alias of %s.",
+ inst, inst_fragment, unit_name);
+ continue;
+ }
+
+ if (!streq(unit_name, inst))
+ log_info("%s: %s has alias %s", __func__, unit_name, inst);
+ r = set_consume(names, TAKE_PTR(inst));
+ if (r < 0)
+ return r;
+ }
+ }
+ }
+
+ *ret_fragment_path = fragment;
+ *ret_names = TAKE_PTR(names);
+
+ // FIXME: if instance, consider any unit names with different template name
+ return 0;
+}
projects / thirdparty / systemd.git / blobdiff