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From: "Johannes Schindelin via GitGitGadget" <gitgitgadget@gmail•com>
To: git@vger•kernel.org
Cc: Ben Knoble <ben.knoble@gmail•com>, Johannes Sixt <j6t@kdbg•org>,
	Karsten Blees <karsten.blees@gmail•com>,
	Johannes Schindelin <johannes.schindelin@gmx•de>,
	Johannes Schindelin <johannes.schindelin@gmx•de>
Subject: [PATCH v2 17/18] mingw: emulate `stat()` a little more faithfully
Date: Fri, 09 Jan 2026 20:05:14 +0000	[thread overview]
Message-ID: <40c3f7f36e945c49cb8c86a431cdcca2d728ec82.1767989115.git.gitgitgadget@gmail.com> (raw)
In-Reply-To: <pull.2018.v2.git.1767989115.gitgitgadget@gmail.com>

From: Johannes Schindelin <johannes.schindelin@gmx•de>

When creating directories via `safe_create_leading_directories()`, we
might encounter an already-existing directory which is not
readable by the current user. To handle that situation, Git's code calls
`stat()` to determine whether we're looking at a directory.

In such a case, `CreateFile()` will fail, though, no matter what, and
consequently `mingw_stat()` will fail, too. But POSIX semantics seem to
still allow `stat()` to go forward.

So let's call `mingw_lstat()` to the rescue if we fail to get a file
handle due to denied permission in `mingw_stat()`, and fill the stat
info that way.

We need to be careful to not allow this to go forward in case that we're
looking at a symbolic link: to resolve the link, we would still have to
create a file handle, and we just found out that we cannot. Therefore,
`stat()` still needs to fail with `EACCES` in that case.

This fixes https://github.com/git-for-windows/git/issues/2531.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx•de>
---
 compat/mingw.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/compat/mingw.c b/compat/mingw.c
index 3e2110a87a..628a3941d2 100644
--- a/compat/mingw.c
+++ b/compat/mingw.c
@@ -1273,7 +1273,19 @@ int mingw_stat(const char *file_name, struct stat *buf)
 			FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE, NULL,
 			OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS, NULL);
 	if (hnd == INVALID_HANDLE_VALUE) {
-		errno = err_win_to_posix(GetLastError());
+		DWORD err = GetLastError();
+
+		if (err == ERROR_ACCESS_DENIED &&
+		    !mingw_lstat(file_name, buf) &&
+		    !S_ISLNK(buf->st_mode))
+			/*
+			 * POSIX semantics state to still try to fill
+			 * information, even if permission is denied to create
+			 * a file handle.
+			 */
+			return 0;
+
+		errno = err_win_to_posix(err);
 		return -1;
 	}
 	result = get_file_info_by_handle(hnd, buf);
-- 
gitgitgadget


  parent reply	other threads:[~2026-01-09 20:05 UTC|newest]

Thread overview: 51+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-12-17 14:08 [PATCH 00/18] Support symbolic links on Windows Johannes Schindelin via GitGitGadget
2025-12-17 14:08 ` [PATCH 01/18] mingw: don't call `GetFileAttributes()` twice in `mingw_lstat()` Karsten Blees via GitGitGadget
2025-12-18 10:34   ` Johannes Sixt
2025-12-17 14:08 ` [PATCH 02/18] mingw: implement `stat()` with symlink support Karsten Blees via GitGitGadget
2025-12-18 10:44   ` Johannes Sixt
2026-01-09 20:04     ` Johannes Schindelin
2025-12-17 14:08 ` [PATCH 03/18] mingw: drop the separate `do_lstat()` function Karsten Blees via GitGitGadget
2025-12-18 10:48   ` Johannes Sixt
2025-12-17 14:08 ` [PATCH 04/18] mingw: let `mingw_lstat()` error early upon problems with reparse points Karsten Blees via GitGitGadget
2025-12-17 14:08 ` [PATCH 05/18] mingw: teach dirent about symlinks Karsten Blees via GitGitGadget
2025-12-17 14:08 ` [PATCH 06/18] mingw: compute the correct size for symlinks in `mingw_lstat()` Bill Zissimopoulos via GitGitGadget
2025-12-17 14:08 ` [PATCH 07/18] mingw: factor out the retry logic Karsten Blees via GitGitGadget
2025-12-17 14:08 ` [PATCH 08/18] mingw: change default of `core.symlinks` to false Karsten Blees via GitGitGadget
2025-12-17 14:08 ` [PATCH 09/18] mingw: add symlink-specific error codes Karsten Blees via GitGitGadget
2025-12-17 14:08 ` [PATCH 10/18] mingw: handle symlinks to directories in `mingw_unlink()` Karsten Blees via GitGitGadget
2025-12-18  2:49   ` Ben Knoble
2026-01-09 20:04     ` Johannes Schindelin
2025-12-17 14:08 ` [PATCH 11/18] mingw: support renaming symlinks Karsten Blees via GitGitGadget
2025-12-18 17:44   ` Johannes Sixt
2026-01-09 20:04     ` Johannes Schindelin
2025-12-17 14:08 ` [PATCH 12/18] mingw: allow `mingw_chdir()` to change to symlink-resolved directories Karsten Blees via GitGitGadget
2025-12-17 14:08 ` [PATCH 13/18] mingw: implement `readlink()` Karsten Blees via GitGitGadget
2025-12-18 18:13   ` Johannes Sixt
2026-01-09 20:04     ` Johannes Schindelin
2025-12-17 14:08 ` [PATCH 14/18] mingw: implement basic `symlink()` functionality (file symlinks only) Karsten Blees via GitGitGadget
2025-12-17 14:08 ` [PATCH 15/18] mingw: add support for symlinks to directories Karsten Blees via GitGitGadget
2025-12-17 14:08 ` [PATCH 16/18] mingw: try to create symlinks without elevated permissions Johannes Schindelin via GitGitGadget
2025-12-17 14:08 ` [PATCH 17/18] mingw: emulate `stat()` a little more faithfully Johannes Schindelin via GitGitGadget
2025-12-17 14:08 ` [PATCH 18/18] mingw: special-case index entries for symlinks with buggy size Johannes Schindelin via GitGitGadget
2025-12-18  0:00 ` [PATCH 00/18] Support symbolic links on Windows Junio C Hamano
2025-12-18 18:51 ` Johannes Sixt
2025-12-18 19:33   ` Karsten Blees
2026-01-09 20:04 ` [PATCH v2 " Johannes Schindelin via GitGitGadget
2026-01-09 20:04   ` [PATCH v2 01/18] mingw: don't call `GetFileAttributes()` twice in `mingw_lstat()` Karsten Blees via GitGitGadget
2026-01-09 20:04   ` [PATCH v2 02/18] mingw: implement `stat()` with symlink support Karsten Blees via GitGitGadget
2026-01-09 20:05   ` [PATCH v2 03/18] mingw: drop the separate `do_lstat()` function Karsten Blees via GitGitGadget
2026-01-09 20:05   ` [PATCH v2 04/18] mingw: let `mingw_lstat()` error early upon problems with reparse points Karsten Blees via GitGitGadget
2026-01-09 20:05   ` [PATCH v2 05/18] mingw: teach dirent about symlinks Karsten Blees via GitGitGadget
2026-01-09 20:05   ` [PATCH v2 06/18] mingw: compute the correct size for symlinks in `mingw_lstat()` Bill Zissimopoulos via GitGitGadget
2026-01-09 20:05   ` [PATCH v2 07/18] mingw: factor out the retry logic Karsten Blees via GitGitGadget
2026-01-09 20:05   ` [PATCH v2 08/18] mingw: change default of `core.symlinks` to false Karsten Blees via GitGitGadget
2026-01-09 20:05   ` [PATCH v2 09/18] mingw: add symlink-specific error codes Karsten Blees via GitGitGadget
2026-01-09 20:05   ` [PATCH v2 10/18] mingw: handle symlinks to directories in `mingw_unlink()` Karsten Blees via GitGitGadget
2026-01-09 20:05   ` [PATCH v2 11/18] mingw: support renaming symlinks Karsten Blees via GitGitGadget
2026-01-09 20:05   ` [PATCH v2 12/18] mingw: allow `mingw_chdir()` to change to symlink-resolved directories Karsten Blees via GitGitGadget
2026-01-09 20:05   ` [PATCH v2 13/18] mingw: implement `readlink()` Karsten Blees via GitGitGadget
2026-01-09 20:05   ` [PATCH v2 14/18] mingw: implement basic `symlink()` functionality (file symlinks only) Karsten Blees via GitGitGadget
2026-01-09 20:05   ` [PATCH v2 15/18] mingw: add support for symlinks to directories Karsten Blees via GitGitGadget
2026-01-09 20:05   ` [PATCH v2 16/18] mingw: try to create symlinks without elevated permissions Johannes Schindelin via GitGitGadget
2026-01-09 20:05   ` Johannes Schindelin via GitGitGadget [this message]
2026-01-09 20:05   ` [PATCH v2 18/18] mingw: special-case index entries for symlinks with buggy size Johannes Schindelin via GitGitGadget

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