a5648b8094
chase_symlinks() would return negative on error, and either a non-negative status or a non-negative fd when CHASE_OPEN was given. This made the interface quite complicated, because dependning on the flags used, we would get two different "types" of return object. Coverity was always confused by this, and flagged every use of chase_symlinks() without CHASE_OPEN as a resource leak (because it would this that an fd is returned). This patch uses a saparate output parameter, so there is no confusion. (I think it is OK to have functions which return either an error or an fd. It's only returning *either* an fd or a non-fd that is confusing.)
560 lines
24 KiB
C
560 lines
24 KiB
C
/* SPDX-License-Identifier: LGPL-2.1+ */
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#include "dirent-util.h"
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#include "fd-util.h"
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#include "fs-util.h"
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#include "macro.h"
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#include "path-lookup.h"
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#include "set.h"
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#include "special.h"
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#include "stat-util.h"
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#include "string-util.h"
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#include "strv.h"
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#include "unit-file.h"
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bool unit_type_may_alias(UnitType type) {
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return IN_SET(type,
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UNIT_SERVICE,
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UNIT_SOCKET,
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UNIT_TARGET,
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UNIT_DEVICE,
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UNIT_TIMER,
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UNIT_PATH);
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}
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bool unit_type_may_template(UnitType type) {
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return IN_SET(type,
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UNIT_SERVICE,
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UNIT_SOCKET,
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UNIT_TARGET,
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UNIT_TIMER,
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UNIT_PATH);
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}
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int unit_validate_alias_symlink_and_warn(const char *filename, const char *target) {
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const char *src, *dst;
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_cleanup_free_ char *src_instance = NULL, *dst_instance = NULL;
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UnitType src_unit_type, dst_unit_type;
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int src_name_type, dst_name_type;
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/* Check if the *alias* symlink is valid. This applies to symlinks like
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* /etc/systemd/system/dbus.service → dbus-broker.service, but not to .wants or .requires symlinks
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* and such. Neither does this apply to symlinks which *link* units, i.e. symlinks to outside of the
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* unit lookup path.
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*
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* -EINVAL is returned if the something is wrong with the source filename or the source unit type is
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* not allowed to symlink,
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* -EXDEV if the target filename is not a valid unit name or doesn't match the source.
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*/
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src = basename(filename);
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dst = basename(target);
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/* src checks */
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src_name_type = unit_name_to_instance(src, &src_instance);
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if (src_name_type < 0)
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return log_notice_errno(src_name_type,
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"%s: not a valid unit name \"%s\": %m", filename, src);
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src_unit_type = unit_name_to_type(src);
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assert(src_unit_type >= 0); /* unit_name_to_instance() checked the suffix already */
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if (!unit_type_may_alias(src_unit_type))
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return log_notice_errno(SYNTHETIC_ERRNO(EINVAL),
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"%s: symlinks are not allowed for units of this type, rejecting.",
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filename);
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if (src_name_type != UNIT_NAME_PLAIN &&
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!unit_type_may_template(src_unit_type))
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return log_notice_errno(SYNTHETIC_ERRNO(EINVAL),
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"%s: templates not allowed for %s units, rejecting.",
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filename, unit_type_to_string(src_unit_type));
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/* dst checks */
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dst_name_type = unit_name_to_instance(dst, &dst_instance);
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if (dst_name_type < 0)
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return log_notice_errno(dst_name_type == -EINVAL ? SYNTHETIC_ERRNO(EXDEV) : dst_name_type,
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"%s points to \"%s\" which is not a valid unit name: %m",
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filename, dst);
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if (!(dst_name_type == src_name_type ||
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(src_name_type == UNIT_NAME_INSTANCE && dst_name_type == UNIT_NAME_TEMPLATE)))
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return log_notice_errno(SYNTHETIC_ERRNO(EXDEV),
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"%s: symlink target name type \"%s\" does not match source, rejecting.",
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filename, dst);
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if (dst_name_type == UNIT_NAME_INSTANCE) {
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assert(src_instance);
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assert(dst_instance);
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if (!streq(src_instance, dst_instance))
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return log_notice_errno(SYNTHETIC_ERRNO(EXDEV),
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"%s: unit symlink target \"%s\" instance name doesn't match, rejecting.",
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filename, dst);
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}
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dst_unit_type = unit_name_to_type(dst);
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if (dst_unit_type != src_unit_type)
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return log_notice_errno(SYNTHETIC_ERRNO(EXDEV),
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"%s: symlink target \"%s\" has incompatible suffix, rejecting.",
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filename, dst);
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return 0;
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}
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#define FOLLOW_MAX 8
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static int unit_ids_map_get(
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Hashmap *unit_ids_map,
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const char *unit_name,
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const char **ret_fragment_path) {
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/* Resolve recursively until we hit an absolute path, i.e. a non-aliased unit.
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*
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* We distinguish the case where unit_name was not found in the hashmap at all, and the case where
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* some symlink was broken.
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*
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* If a symlink target points to an instance name, then we also check for the template. */
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const char *id = NULL;
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int r;
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for (unsigned n = 0; n < FOLLOW_MAX; n++) {
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const char *t = hashmap_get(unit_ids_map, id ?: unit_name);
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if (!t) {
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_cleanup_free_ char *template = NULL;
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if (!id)
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return -ENOENT;
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r = unit_name_template(id, &template);
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if (r == -EINVAL)
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return -ENXIO; /* we failed to find the symlink target */
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if (r < 0)
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return log_error_errno(r, "Failed to determine template name for %s: %m", id);
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t = hashmap_get(unit_ids_map, template);
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if (!t)
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return -ENXIO;
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/* We successfully switched from instanced name to a template, let's continue */
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}
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if (path_is_absolute(t)) {
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if (ret_fragment_path)
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*ret_fragment_path = t;
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return 0;
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}
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id = t;
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}
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return -ELOOP;
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}
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static bool lookup_paths_mtime_exclude(const LookupPaths *lp, const char *path) {
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/* Paths that are under our exclusive control. Users shall not alter those directly. */
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return streq_ptr(path, lp->generator) ||
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streq_ptr(path, lp->generator_early) ||
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streq_ptr(path, lp->generator_late) ||
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streq_ptr(path, lp->transient) ||
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streq_ptr(path, lp->persistent_control) ||
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streq_ptr(path, lp->runtime_control);
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}
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static bool lookup_paths_mtime_good(const LookupPaths *lp, usec_t mtime) {
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char **dir;
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STRV_FOREACH(dir, (char**) lp->search_path) {
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struct stat st;
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if (lookup_paths_mtime_exclude(lp, *dir))
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continue;
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/* Determine the latest lookup path modification time */
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if (stat(*dir, &st) < 0) {
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if (errno == ENOENT)
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continue;
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log_debug_errno(errno, "Failed to stat %s, ignoring: %m", *dir);
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continue;
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}
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if (timespec_load(&st.st_mtim) > mtime) {
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log_debug_errno(errno, "Unit dir %s has changed, need to update cache.", *dir);
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return false;
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}
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}
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return true;
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}
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int unit_file_build_name_map(
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const LookupPaths *lp,
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usec_t *cache_mtime,
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Hashmap **ret_unit_ids_map,
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Hashmap **ret_unit_names_map,
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Set **ret_path_cache) {
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/* Build two mappings: any name → main unit (i.e. the end result of symlink resolution), unit name →
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* all aliases (i.e. the entry for a given key is a a list of all names which point to this key). The
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* key is included in the value iff we saw a file or symlink with that name. In other words, if we
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* have a key, but it is not present in the value for itself, there was an alias pointing to it, but
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* the unit itself is not loadable.
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*
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* At the same, build a cache of paths where to find units.
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*/
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_cleanup_hashmap_free_ Hashmap *ids = NULL, *names = NULL;
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_cleanup_set_free_free_ Set *paths = NULL;
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char **dir;
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int r;
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usec_t mtime = 0;
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/* Before doing anything, check if the mtime that was passed is still valid. If
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* yes, do nothing. If *cache_time == 0, always build the cache. */
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if (cache_mtime && *cache_mtime > 0 && lookup_paths_mtime_good(lp, *cache_mtime))
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return 0;
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if (ret_path_cache) {
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paths = set_new(&path_hash_ops);
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if (!paths)
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return log_oom();
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}
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STRV_FOREACH(dir, (char**) lp->search_path) {
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struct dirent *de;
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_cleanup_closedir_ DIR *d = NULL;
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struct stat st;
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d = opendir(*dir);
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if (!d) {
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if (errno != ENOENT)
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log_warning_errno(errno, "Failed to open \"%s\", ignoring: %m", *dir);
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continue;
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}
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/* Determine the latest lookup path modification time */
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if (fstat(dirfd(d), &st) < 0)
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return log_error_errno(errno, "Failed to fstat %s: %m", *dir);
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if (!lookup_paths_mtime_exclude(lp, *dir))
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mtime = MAX(mtime, timespec_load(&st.st_mtim));
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FOREACH_DIRENT_ALL(de, d, log_warning_errno(errno, "Failed to read \"%s\", ignoring: %m", *dir)) {
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char *filename;
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_cleanup_free_ char *_filename_free = NULL, *simplified = NULL;
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const char *suffix, *dst = NULL;
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bool valid_unit_name;
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valid_unit_name = unit_name_is_valid(de->d_name, UNIT_NAME_ANY);
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/* We only care about valid units and dirs with certain suffixes, let's ignore the
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* rest. */
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if (!valid_unit_name &&
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!ENDSWITH_SET(de->d_name, ".wants", ".requires", ".d"))
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continue;
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filename = path_join(*dir, de->d_name);
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if (!filename)
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return log_oom();
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if (ret_path_cache) {
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r = set_consume(paths, filename);
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if (r < 0)
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return log_oom();
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/* We will still use filename below. This is safe because we know the set
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* holds a reference. */
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} else
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_filename_free = filename; /* Make sure we free the filename. */
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if (!valid_unit_name)
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continue;
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assert_se(suffix = strrchr(de->d_name, '.'));
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/* search_path is ordered by priority (highest first). If the name is already mapped
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* to something (incl. itself), it means that we have already seen it, and we should
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* ignore it here. */
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if (hashmap_contains(ids, de->d_name))
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continue;
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dirent_ensure_type(d, de);
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if (de->d_type == DT_LNK) {
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/* We don't explicitly check for alias loops here. unit_ids_map_get() which
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* limits the number of hops should be used to access the map. */
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_cleanup_free_ char *target = NULL, *target_abs = NULL;
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r = readlinkat_malloc(dirfd(d), de->d_name, &target);
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if (r < 0) {
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log_warning_errno(r, "Failed to read symlink %s/%s, ignoring: %m",
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*dir, de->d_name);
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continue;
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}
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if (!path_is_absolute(target)) {
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target_abs = path_join(*dir, target);
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if (!target_abs)
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return log_oom();
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free_and_replace(target, target_abs);
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}
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/* Get rid of "." and ".." components in target path */
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r = chase_symlinks(target, lp->root_dir, CHASE_NOFOLLOW | CHASE_NONEXISTENT, &simplified, NULL);
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if (r < 0) {
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log_warning_errno(r, "Failed to resolve symlink %s pointing to %s, ignoring: %m",
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filename, target);
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continue;
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}
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/* Check if the symlink goes outside of our search path.
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* If yes, it's a linked unit file or mask, and we don't care about the target name.
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* Let's just store the link destination directly.
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* If not, let's verify that it's a good symlink. */
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char *tail = path_startswith_strv(simplified, lp->search_path);
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if (tail) {
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bool self_alias;
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dst = basename(simplified);
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self_alias = streq(dst, de->d_name);
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if (is_path(tail))
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log_full(self_alias ? LOG_DEBUG : LOG_WARNING,
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"Suspicious symlink %s→%s, treating as alias.",
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filename, simplified);
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r = unit_validate_alias_symlink_and_warn(filename, simplified);
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if (r < 0)
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continue;
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if (self_alias) {
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/* A self-alias that has no effect */
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log_debug("%s: self-alias: %s/%s → %s, ignoring.",
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__func__, *dir, de->d_name, dst);
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continue;
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}
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log_debug("%s: alias: %s/%s → %s", __func__, *dir, de->d_name, dst);
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} else {
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dst = simplified;
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log_debug("%s: linked unit file: %s/%s → %s", __func__, *dir, de->d_name, dst);
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}
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} else {
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dst = filename;
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log_debug("%s: normal unit file: %s", __func__, dst);
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}
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r = hashmap_put_strdup(&ids, de->d_name, dst);
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if (r < 0)
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return log_warning_errno(r, "Failed to add entry to hashmap (%s→%s): %m",
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de->d_name, dst);
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}
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}
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/* Let's also put the names in the reverse db. */
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Iterator it;
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const char *dummy, *src;
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HASHMAP_FOREACH_KEY(dummy, src, ids, it) {
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const char *dst;
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r = unit_ids_map_get(ids, src, &dst);
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if (r < 0)
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continue;
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if (null_or_empty_path(dst) != 0)
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continue;
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/* Do not treat instance symlinks that point to the template as aliases */
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if (unit_name_is_valid(basename(dst), UNIT_NAME_TEMPLATE) &&
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unit_name_is_valid(src, UNIT_NAME_INSTANCE))
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continue;
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r = string_strv_hashmap_put(&names, basename(dst), src);
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if (r < 0)
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return log_warning_errno(r, "Failed to add entry to hashmap (%s→%s): %m",
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basename(dst), src);
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}
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if (cache_mtime)
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*cache_mtime = mtime;
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*ret_unit_ids_map = TAKE_PTR(ids);
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*ret_unit_names_map = TAKE_PTR(names);
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if (ret_path_cache)
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*ret_path_cache = TAKE_PTR(paths);
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return 1;
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}
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int unit_file_find_fragment(
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Hashmap *unit_ids_map,
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Hashmap *unit_name_map,
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const char *unit_name,
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const char **ret_fragment_path,
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Set **ret_names) {
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const char *fragment = NULL;
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_cleanup_free_ char *template = NULL, *instance = NULL;
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_cleanup_set_free_free_ Set *names = NULL;
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char **t, **nnn;
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int r, name_type;
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/* Finds a fragment path, and returns the set of names:
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* if we have …/foo.service and …/foo-alias.service→foo.service,
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* and …/foo@.service and …/foo-alias@.service→foo@.service,
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* and …/foo@inst.service,
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* this should return:
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* foo.service → …/foo.service, {foo.service, foo-alias.service},
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* foo-alias.service → …/foo.service, {foo.service, foo-alias.service},
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* foo@.service → …/foo@.service, {foo@.service, foo-alias@.service},
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* foo-alias@.service → …/foo@.service, {foo@.service, foo-alias@.service},
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* foo@bar.service → …/foo@.service, {foo@bar.service, foo-alias@bar.service},
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* foo-alias@bar.service → …/foo@.service, {foo@bar.service, foo-alias@bar.service},
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* foo-alias@inst.service → …/foo@inst.service, {foo@inst.service, foo-alias@inst.service}.
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*/
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name_type = unit_name_to_instance(unit_name, &instance);
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if (name_type < 0)
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return name_type;
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names = set_new(&string_hash_ops);
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if (!names)
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return -ENOMEM;
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/* The unit always has its own name if it's not a template. */
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if (IN_SET(name_type, UNIT_NAME_PLAIN, UNIT_NAME_INSTANCE)) {
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r = set_put_strdup(names, unit_name);
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if (r < 0)
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return r;
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}
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/* First try to load fragment under the original name */
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r = unit_ids_map_get(unit_ids_map, unit_name, &fragment);
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if (r < 0 && !IN_SET(r, -ENOENT, -ENXIO))
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return log_debug_errno(r, "Cannot load unit %s: %m", unit_name);
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if (fragment) {
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/* Add any aliases of the original name to the set of names */
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nnn = hashmap_get(unit_name_map, basename(fragment));
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STRV_FOREACH(t, nnn) {
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if (name_type == UNIT_NAME_INSTANCE && unit_name_is_valid(*t, UNIT_NAME_TEMPLATE)) {
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char *inst;
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r = unit_name_replace_instance(*t, instance, &inst);
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if (r < 0)
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return log_debug_errno(r, "Cannot build instance name %s+%s: %m", *t, instance);
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if (!streq(unit_name, inst))
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log_debug("%s: %s has alias %s", __func__, unit_name, inst);
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log_info("%s: %s+%s → %s", __func__, *t, instance, inst);
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r = set_consume(names, inst);
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} else {
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if (!streq(unit_name, *t))
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log_debug("%s: %s has alias %s", __func__, unit_name, *t);
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r = set_put_strdup(names, *t);
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}
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if (r < 0)
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return r;
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}
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}
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if (!fragment && name_type == UNIT_NAME_INSTANCE) {
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/* Look for a fragment under the template name */
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r = unit_name_template(unit_name, &template);
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if (r < 0)
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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", template);
|
|
|
|
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_debug("%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;
|
|
}
|
|
|
|
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;
|
|
size_t i;
|
|
|
|
if (!word)
|
|
return NULL;
|
|
|
|
if (in_initrd()) {
|
|
word = startswith(word, "rd.");
|
|
if (!word)
|
|
return NULL;
|
|
}
|
|
|
|
rlmap_ptr = in_initrd() ? rlmap_initrd : rlmap;
|
|
|
|
for (i = 0; rlmap_ptr[i]; i += 2)
|
|
if (streq(word, rlmap_ptr[i]))
|
|
return rlmap_ptr[i+1];
|
|
|
|
return NULL;
|
|
}
|