From: Zbigniew Jędrzejewski-Szmek <zbyszek@in.waw.pl>
Date: Tue, 19 Mar 2024 22:35:32 +0000 (+0100)
Subject: basic/unit-name: use strdup_to() in slice_build_parent_slice()
X-Git-Tag: v256-rc1~459^2~3
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=196166dbb1e65a4d942170cb3856cb7e6d28c6d0;p=thirdparty%2Fsystemd.git

basic/unit-name: use strdup_to() in slice_build_parent_slice()

The handling of the buffer is not obvious, so add a comment.
---

diff --git a/src/basic/unit-name.c b/src/basic/unit-name.c
index a84b14568d9..4e2f77c03dc 100644
--- a/src/basic/unit-name.c
+++ b/src/basic/unit-name.c
@@ -797,10 +797,6 @@ good:
 }
 
 int slice_build_parent_slice(const char *slice, char **ret) {
-        _cleanup_free_ char *s = NULL;
-        char *dash;
-        int r;
-
         assert(slice);
         assert(ret);
 
@@ -812,18 +808,16 @@ int slice_build_parent_slice(const char *slice, char **ret) {
                 return 0;
         }
 
-        s = strdup(slice);
+        _cleanup_free_ char *s = strdup(slice);
         if (!s)
                 return -ENOMEM;
 
-        dash = strrchr(s, '-');
-        if (dash)
-                strcpy(dash, ".slice");
-        else {
-                r = free_and_strdup(&s, SPECIAL_ROOT_SLICE);
-                if (r < 0)
-                        return r;
-        }
+        char *dash = strrchr(s, '-');
+        if (!dash)
+                return strdup_to_full(ret, SPECIAL_ROOT_SLICE);
+
+        /* We know that s ended with .slice before truncation, so we have enough space. */
+        strcpy(dash, ".slice");
 
         *ret = TAKE_PTR(s);
         return 1;