From a3839ade4ea27ca7a8c5c5a02d10b74dc9e54d96 Mon Sep 17 00:00:00 2001
From: dongshengyuan <545258830@qq.com>
Date: Wed, 5 Aug 2026 12:18:03 +0800
Subject: [PATCH] sysupdate: allow long CurrentSymlink= paths

CurrentSymlink= accepts a symlink path, but the parser used NAME_MAX
for specifier expansion. Absolute and target-relative paths can be
longer than one filename component while still staying below PATH_MAX.

Reproducer: configure CurrentSymlink= to a path longer than NAME_MAX
and run systemd-sysupdate list with debug logging.

Before: sysupdate logged that CurrentSymlink= specifier expansion
failed and ignored the setting.

After: the transfer parses cleanly and list emits no CurrentSymlink=
specifier expansion warning.

Follow-up for: 43cc7a3ef4f6a89946e7ffd6a3112a0c1740b1ef
---
 src/sysupdate/sysupdate-transfer.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/sysupdate/sysupdate-transfer.c b/src/sysupdate/sysupdate-transfer.c
index a03bbbb63f..226dbd93ae 100644
--- a/src/sysupdate/sysupdate-transfer.c
+++ b/src/sysupdate/sysupdate-transfer.c
@@ -238,7 +238,12 @@ static int config_parse_current_symlink(
 
         assert(rvalue);
 
-        r = specifier_printf(rvalue, NAME_MAX, system_and_tmp_specifier_table, t->context->root, NULL, &resolved);
+        if (isempty(rvalue)) {
+                *current_symlink = mfree(*current_symlink);
+                return 0;
+        }
+
+        r = specifier_printf(rvalue, PATH_MAX-1, system_and_tmp_specifier_table, t->context->root, NULL, &resolved);
         if (r < 0) {
                 log_syntax(unit, LOG_WARNING, filename, line, r,
                            "Failed to expand specifiers in CurrentSymlink=, ignoring: %s", rvalue);