From: "Karsten Blees 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>,
Karsten Blees <karsten.blees@gmail•com>
Subject: [PATCH v2 13/18] mingw: implement `readlink()`
Date: Fri, 09 Jan 2026 20:05:10 +0000 [thread overview]
Message-ID: <1ae9c63a89e6b35d1658042685fdec0a572b375a.1767989115.git.gitgitgadget@gmail.com> (raw)
In-Reply-To: <pull.2018.v2.git.1767989115.gitgitgadget@gmail.com>
From: Karsten Blees <karsten.blees@gmail•com>
Implement `readlink()` by reading NTFS reparse points via the
`read_reparse_point()` function that was introduced earlier to determine
the length of symlink targets. Works for symlinks and directory
junctions.
Signed-off-by: Karsten Blees <karsten.blees@gmail•com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx•de>
---
compat/mingw-posix.h | 3 +--
compat/mingw.c | 24 ++++++++++++++++++++++++
2 files changed, 25 insertions(+), 2 deletions(-)
diff --git a/compat/mingw-posix.h b/compat/mingw-posix.h
index 0939feff27..896aa976b1 100644
--- a/compat/mingw-posix.h
+++ b/compat/mingw-posix.h
@@ -121,8 +121,6 @@ struct utsname {
* trivial stubs
*/
-static inline int readlink(const char *path UNUSED, char *buf UNUSED, size_t bufsiz UNUSED)
-{ errno = ENOSYS; return -1; }
static inline int symlink(const char *oldpath UNUSED, const char *newpath UNUSED)
{ errno = ENOSYS; return -1; }
static inline int fchmod(int fildes UNUSED, mode_t mode UNUSED)
@@ -197,6 +195,7 @@ int setitimer(int type, struct itimerval *in, struct itimerval *out);
int sigaction(int sig, struct sigaction *in, struct sigaction *out);
int link(const char *oldpath, const char *newpath);
int uname(struct utsname *buf);
+int readlink(const char *path, char *buf, size_t bufsiz);
/*
* replacements of existing functions
diff --git a/compat/mingw.c b/compat/mingw.c
index 5d2a8c247c..b407a2ac07 100644
--- a/compat/mingw.c
+++ b/compat/mingw.c
@@ -2698,6 +2698,30 @@ int link(const char *oldpath, const char *newpath)
return 0;
}
+int readlink(const char *path, char *buf, size_t bufsiz)
+{
+ WCHAR wpath[MAX_PATH];
+ char tmpbuf[MAX_PATH];
+ int len;
+ DWORD tag;
+
+ if (xutftowcs_path(wpath, path) < 0)
+ return -1;
+
+ if (read_reparse_point(wpath, TRUE, tmpbuf, &len, &tag) < 0)
+ return -1;
+
+ /*
+ * Adapt to strange readlink() API: Copy up to bufsiz *bytes*, potentially
+ * cutting off a UTF-8 sequence. Insufficient bufsize is *not* a failure
+ * condition. There is no conversion function that produces invalid UTF-8,
+ * so convert to a (hopefully large enough) temporary buffer, then memcpy
+ * the requested number of bytes (including '\0' for robustness).
+ */
+ memcpy(buf, tmpbuf, min(bufsiz, len + 1));
+ return min(bufsiz, len);
+}
+
pid_t waitpid(pid_t pid, int *status, int options)
{
HANDLE h = OpenProcess(SYNCHRONIZE | PROCESS_QUERY_INFORMATION,
--
gitgitgadget
next prev 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 ` Karsten Blees via GitGitGadget [this message]
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 ` [PATCH v2 17/18] mingw: emulate `stat()` a little more faithfully Johannes Schindelin via GitGitGadget
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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