From: Yu Watanabe <watanabe.yu+github@gmail.com>
Date: Mon, 28 Jul 2025 18:25:17 +0000 (+0900)
Subject: chase: check the result is a directory or regular file only when the resolved path... 
X-Git-Tag: v258-rc2~55^2~1
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=1cabb6905b98ecc11bfb1fd8305c8f5c089e5c32;p=thirdparty%2Fsystemd.git

chase: check the result is a directory or regular file only when the resolved path exists

Otherwise, if it is called with CHASE_NONEXISTENT, when we call
stat_verify_directory()/_regular() the struct stat is for one of the
parent directory, rather than for the result path.

With this change, we can safely specify CHASE_MUST_BE_DIRECTORY/REGULAR
with CHASE_NONEXISTENT.

More importantly, chaseat() internally sets CHASE_MUST_BE_DIRECTORY when
the input path ends with "/", "/,", "/..". Hence, without this change,
we cannot specify CHASE_NONEXISTENT safely.

Follow-up for 90b9f7a07e6f57825f416f6ce2db0a9f2086754b.
---

diff --git a/src/basic/chase.c b/src/basic/chase.c
index 3a929498bf2..68bb9816ce4 100644
--- a/src/basic/chase.c
+++ b/src/basic/chase.c
@@ -509,16 +509,18 @@ int chaseat(int dir_fd, const char *path, ChaseFlags flags, char **ret_path, int
                 close_and_replace(fd, child);
         }
 
-        if (FLAGS_SET(flags, CHASE_MUST_BE_DIRECTORY)) {
-                r = stat_verify_directory(&st);
-                if (r < 0)
-                        return r;
-        }
+        if (exists) {
+                if (FLAGS_SET(flags, CHASE_MUST_BE_DIRECTORY)) {
+                        r = stat_verify_directory(&st);
+                        if (r < 0)
+                                return r;
+                }
 
-        if (FLAGS_SET(flags, CHASE_MUST_BE_REGULAR)) {
-                r = stat_verify_regular(&st);
-                if (r < 0)
-                        return r;
+                if (FLAGS_SET(flags, CHASE_MUST_BE_REGULAR)) {
+                        r = stat_verify_regular(&st);
+                        if (r < 0)
+                                return r;
+                }
         }
 
         if (ret_path) {