From: Mike Yuan <me@yhndnzj.com>
Date: Wed, 8 Nov 2023 17:43:08 +0000 (+0800)
Subject: basic/fileio: drop O_CREAT before passing flags to fd_reopen
X-Git-Tag: v255-rc2~69^2
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=refs%2Fpull%2F29939%2Fhead;p=thirdparty%2Fsystemd.git

basic/fileio: drop O_CREAT before passing flags to fd_reopen

Follow-up for 78c21009bfcf0758f9c85dc70ac896c8aab6b535

Fixes #29938
---

diff --git a/src/basic/fileio.c b/src/basic/fileio.c
index 6129461e660..a050b61db45 100644
--- a/src/basic/fileio.c
+++ b/src/basic/fileio.c
@@ -1064,7 +1064,9 @@ int fdopen_independent(int fd, const char *mode, FILE **ret) {
         if (mode_flags < 0)
                 return mode_flags;
 
-        copy_fd = fd_reopen(fd, mode_flags);
+        /* Flags returned by fopen_mode_to_flags might contain O_CREAT, but it doesn't make sense for fd_reopen
+         * since we're working on an existing fd anyway. Let's drop it here to avoid triggering assertion. */
+        copy_fd = fd_reopen(fd, mode_flags & ~O_CREAT);
         if (copy_fd < 0)
                 return copy_fd;