From e5b7d2b2c17b1bd80d759350bb6d3cfa1303f687 Mon Sep 17 00:00:00 2001
From: Ron Yorston <rmy@pobox.com>
Date: Fri, 14 May 2021 09:18:53 +0100
Subject: win32: implement futimens(2)/utimensat(2)

The touch applet has been changed to use futimens(2)/utimensat(2).
Provide implementations of these for WIN32.
---
 include/mingw.h | 10 +++++++
 win32/mingw.c   | 82 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 91 insertions(+), 1 deletion(-)

diff --git a/include/mingw.h b/include/mingw.h
index d48237add..89b26762a 100644
--- a/include/mingw.h
+++ b/include/mingw.h
@@ -34,6 +34,9 @@ int inet_pton(int af, const char *src, void *dst);
 #define O_DIRECT 0
 #define O_SPECIAL 0x800000
 
+#define AT_FDCWD -100
+#define AT_SYMLINK_NOFOLLOW 0x100
+
 /*
  * grp.h
  */
@@ -348,6 +351,13 @@ int mingw_fstat(int fd, struct mingw_stat *buf);
 #define stat mingw_stat
 #define fstat mingw_fstat
 
+#define UTIME_NOW  ((1l << 30) - 1l)
+#define UTIME_OMIT ((1l << 30) - 2l)
+
+int utimensat(int fd, const char *path, const struct timespec times[2],
+				int flags);
+int futimens(int fd, const struct timespec times[2]);
+
 /*
  * sys/sysinfo.h
  */
diff --git a/win32/mingw.c b/win32/mingw.c
index 3bb79633a..182e3d4db 100644
--- a/win32/mingw.c
+++ b/win32/mingw.c
@@ -708,6 +708,14 @@ static inline void timeval_to_filetime(const struct timeval tv, FILETIME *ft)
 	ft->dwHighDateTime = winTime >> 32;
 }
 
+static inline void timespec_to_filetime(const struct timespec tv, FILETIME *ft)
+{
+	long long winTime = (tv.tv_sec * 10000000LL) + tv.tv_nsec / 100LL +
+							116444736000000000LL;
+	ft->dwLowDateTime = winTime;
+	ft->dwHighDateTime = winTime >> 32;
+}
+
 int utimes(const char *file_name, const struct timeval tims[2])
 {
 	FILETIME mft, aft;
@@ -731,13 +739,85 @@ int utimes(const char *file_name, const struct timeval tims[2])
 	}
 
 	if (!SetFileTime(fh, NULL, &aft, &mft)) {
-		errno = EINVAL;
+		errno = err_win_to_posix();
 		rc = -1;
 	}
 	CloseHandle(fh);
 	return rc;
 }
 
+static int hutimens(HANDLE fh, const struct timespec times[2])
+{
+	FILETIME now, aft, mft;
+	FILETIME *pft[2] = {&aft, &mft};
+	int i;
+
+	GetSystemTimeAsFileTime(&now);
+
+	if (times) {
+		for (i = 0; i < 2; ++i) {
+			if (times[i].tv_nsec == UTIME_NOW)
+				*pft[i] = now;
+			else if (times[i].tv_nsec == UTIME_OMIT)
+				pft[i] = NULL;
+			else if (times[i].tv_nsec >= 0 && times[i].tv_nsec < 1000000000L)
+				timespec_to_filetime(times[i], pft[i]);
+			else {
+				errno = EINVAL;
+				return -1;
+			}
+		}
+	} else {
+		aft = mft = now;
+	}
+
+	if (!SetFileTime(fh, NULL, pft[0], pft[1])) {
+		errno = err_win_to_posix();
+		return -1;
+	}
+	return 0;
+}
+
+int futimens(int fd, const struct timespec times[2])
+{
+	HANDLE fh;
+
+	fh = (HANDLE)_get_osfhandle(fd);
+	if (fh == INVALID_HANDLE_VALUE) {
+		errno = EBADF;
+		return -1;
+	}
+
+	return hutimens(fh, times);
+}
+
+int utimensat(int fd, const char *path, const struct timespec times[2],
+                int flags)
+{
+	int rc = -1;
+	HANDLE fh;
+	DWORD cflag = FILE_FLAG_BACKUP_SEMANTICS;
+
+	if (!is_absolute_path(path) && fd != AT_FDCWD) {
+		errno = ENOSYS;	// partial implementation
+		return rc;
+	}
+
+	if (flags & AT_SYMLINK_NOFOLLOW)
+		cflag |= FILE_FLAG_OPEN_REPARSE_POINT;
+
+	fh = CreateFile(path, FILE_WRITE_ATTRIBUTES, 0, NULL, OPEN_EXISTING,
+					cflag, NULL);
+	if (fh == INVALID_HANDLE_VALUE) {
+		errno = err_win_to_posix();
+		return rc;
+	}
+
+	rc = hutimens(fh, times);
+	CloseHandle(fh);
+	return rc;
+}
+
 unsigned int sleep (unsigned int seconds)
 {
 	Sleep(seconds*1000);
-- 
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