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214 lines
10 KiB
214 lines
10 KiB
From d49d646d00078b201cdde2978b7941d20acb1d4b Mon Sep 17 00:00:00 2001
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From: =?UTF-8?q?Zbigniew=20J=C4=99drzejewski-Szmek?= <zbyszek@in.waw.pl>
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Date: Wed, 2 Mar 2022 16:53:54 +0100
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Subject: [PATCH] basic/unit-file: split out the subroutine for symlink
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verification
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The old logs used __func__, but this doesn't make sense now, because the
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low-level function will be used in other places. So those are adjusted to be
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more generic.
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(cherry picked from commit 9825181143530af7003fc50567b814dbbee39046)
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Related: #2082131
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---
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src/basic/unit-file.c | 159 +++++++++++++++++++++++++-----------------
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1 file changed, 96 insertions(+), 63 deletions(-)
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diff --git a/src/basic/unit-file.c b/src/basic/unit-file.c
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index 96826e2940..25abce932a 100644
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--- a/src/basic/unit-file.c
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+++ b/src/basic/unit-file.c
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@@ -260,6 +260,83 @@ static int directory_name_is_valid(const char *name) {
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return false;
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}
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+static int unit_file_resolve_symlink(
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+ const char *root_dir,
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+ char **search_path,
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+ const char *dir,
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+ int dirfd,
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+ const char *filename,
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+ char **ret_destination) {
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+
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+ _cleanup_free_ char *target = NULL, *simplified = NULL, *dst = NULL;
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+ int r;
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+
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+ assert(dir);
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+ assert(dirfd >= 0);
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+ assert(filename);
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+ assert(ret_destination);
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+
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+ r = readlinkat_malloc(dirfd, filename, &target);
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+ if (r < 0)
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+ return log_warning_errno(r, "Failed to read symlink %s%s%s: %m",
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+ dir, dir ? "/" : "", filename);
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+
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+ bool is_abs = path_is_absolute(target);
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+ if (root_dir || !is_abs) {
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+ char *target_abs = path_join(is_abs ? root_dir : dir, target);
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+ if (!target_abs)
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+ return log_oom();
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+
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+ free_and_replace(target, target_abs);
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+ }
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+
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+ /* Get rid of "." and ".." components in target path */
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+ r = chase_symlinks(target, root_dir, CHASE_NOFOLLOW | CHASE_NONEXISTENT, &simplified, NULL);
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+ if (r < 0)
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+ return log_warning_errno(r, "Failed to resolve symlink %s/%s pointing to %s: %m",
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+ dir, filename, target);
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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 source directly.
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+ * If not, let's verify that it's a good symlink. */
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+ const char *tail = path_startswith_strv(simplified, search_path);
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+ if (!tail) {
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+ log_debug("Linked unit file: %s/%s → %s", dir, filename, simplified);
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+
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+ dst = path_join(dir, filename);
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+ if (!dst)
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+ return log_oom();
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+
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+ } else {
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+ r = path_extract_filename(simplified, &dst);
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+ if (r < 0)
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+ return r;
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+
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+ bool self_alias = streq(dst, filename);
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+
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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→%s, treating as alias.",
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+ dir, filename, simplified);
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+
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+ r = unit_validate_alias_symlink_and_warn(filename, simplified);
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+ if (r < 0)
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+ return r;
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+
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+ if (self_alias)
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+ /* A self-alias that has no effect */
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+ return log_debug_errno(SYNTHETIC_ERRNO(ELOOP),
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+ "Unit file self-alias: %s/%s → %s, ignoring.",
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+ dir, filename, dst);
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+
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+ log_debug("Unit file alias: %s/%s → %s", dir, filename, dst);
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+ }
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+
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+ *ret_destination = TAKE_PTR(dst);
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+ return 0;
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+}
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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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uint64_t *cache_timestamp_hash,
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@@ -310,10 +387,9 @@ int unit_file_build_name_map(
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FOREACH_DIRENT_ALL(de, d, log_warning_errno(errno, "Failed to read \"%s\", ignoring: %m", *dir)) {
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_unused_ _cleanup_free_ char *_filename_free = NULL;
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- _cleanup_free_ char *simplified = NULL;
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- bool symlink_to_dir = false;
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- const char *dst = NULL;
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char *filename;
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+ _cleanup_free_ char *dst = NULL;
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+ bool symlink_to_dir = false;
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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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@@ -397,77 +473,34 @@ int unit_file_build_name_map(
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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;
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-
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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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+ r = unit_file_resolve_symlink(lp->root_dir, lp->search_path,
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+ *dir, dirfd(d), de->d_name,
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+ &dst);
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+ if (r == -ENOMEM)
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+ return r;
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+ if (r < 0) /* we ignore other errors here */
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continue;
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- }
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- const bool is_abs = path_is_absolute(target);
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- if (lp->root_dir || !is_abs) {
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- char *target_abs = path_join(is_abs ? lp->root_dir : *dir, target);
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- if (!target_abs)
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+ } else {
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+ dst = TAKE_PTR(_filename_free); /* Grab the copy we made previously, if available. */
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+ if (!dst) {
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+ dst = strdup(filename);
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+ if (!dst)
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return log_oom();
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-
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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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-
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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 source 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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- log_debug("%s: linked unit file: %s → %s",
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- __func__, filename, simplified);
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-
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- dst = filename;
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- } else {
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-
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- bool self_alias;
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-
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- dst = basename(simplified);
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- self_alias = streq(dst, de->d_name);
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-
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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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-
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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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-
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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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-
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- log_debug("%s: alias: %s/%s → %s", __func__, *dir, de->d_name, dst);
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- }
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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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+ _cleanup_free_ char *key = strdup(de->d_name);
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+ if (!key)
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+ return log_oom();
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+
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+ r = hashmap_ensure_put(&ids, &string_hash_ops_free_free, key, 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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+ key = dst = NULL;
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}
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}
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