[PATCH v2 2/4] mingw: implement lock_or_unlock_fd_for_appending()
From: Johannes Schindelin via GitGitGadget <hidden>
Date: 2018-08-10 19:47:25
Subsystem:
the rest · Maintainer:
Linus Torvalds
From: Johannes Schindelin <redacted> For some reason, t/t5552-skipping-fetch-negotiator.sh fails particularly often on Windows due to racy tracing where the `git upload-pack` and the `git fetch` processes compete for the same file. We just introduced a remedy that uses fcntl(), but Windows does not have fcntl(). So let's implement an alternative. Signed-off-by: Johannes Schindelin <redacted> --- compat/mingw.c | 19 +++++++++++++++++++ compat/mingw.h | 3 +++ 2 files changed, 22 insertions(+)
diff --git a/compat/mingw.c b/compat/mingw.c
index 6ded1c859..6da9ce861 100644
--- a/compat/mingw.c
+++ b/compat/mingw.c@@ -514,6 +514,25 @@ int mingw_chmod(const char *filename, int mode) return _wchmod(wfilename, mode); } +int mingw_lock_or_unlock_fd_for_appending(int fd, int lock_it) +{ + HANDLE handle = (HANDLE)_get_osfhandle(fd); + OVERLAPPED overlapped = { 0 }; + DWORD err; + + if (!lock_it && UnlockFileEx(handle, 0, -1, 0, &overlapped)) + return 0; + if (lock_it && + LockFileEx(handle, LOCKFILE_EXCLUSIVE_LOCK, 0, -1, 0, &overlapped)) + return 0; + + err = GetLastError(); + /* LockFileEx() cannot lock pipes */ + errno = err == ERROR_INVALID_FUNCTION ? + EBADF : err_win_to_posix(GetLastError()); + return -1; +} + /* * The unit of FILETIME is 100-nanoseconds since January 1, 1601, UTC. * Returns the 100-nanoseconds ("hekto nanoseconds") since the epoch.
diff --git a/compat/mingw.h b/compat/mingw.h
index 571019d0b..0f76d89a9 100644
--- a/compat/mingw.h
+++ b/compat/mingw.h@@ -397,6 +397,9 @@ HANDLE winansi_get_osfhandle(int fd); * git specific compatibility */ +int mingw_lock_or_unlock_fd_for_appending(int fd, int lock_it); +#define lock_or_unlock_fd_for_appending mingw_lock_or_unlock_fd_for_appending + #define has_dos_drive_prefix(path) \ (isalpha(*(path)) && (path)[1] == ':' ? 2 : 0) int mingw_skip_dos_drive_prefix(char **path);
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