Implement test-stat the prints the modification time.

Compile with

   gcc -o test-stat -Wall test-stat.c -DEMULATE
or
   gcc -o test-stat -Wall test-stat.c

test-stat.c

@@ -0,0 +1,170 @@
+#include <sys/stat.h>
+#include <time.h>
+#include <stdio.h>
+
+#ifdef EMULATE
+#define HINT fprintf(stderr, "emulated stat\n")
+#include <errno.h>
+#include <windows.h>
+#include <unistd.h>
+
+/* Use mingw_lstat() instead of lstat()/stat() and
+ * mingw_fstat() instead of fstat() on Windows.
+ */
+int mingw_lstat(const char *file_name, struct stat *buf);
+int mingw_fstat(int fd, struct stat *buf);
+#define fstat mingw_fstat
+#define lstat mingw_lstat
+#define stat(x,y) mingw_lstat(x,y)
+
+#define PATH_MAX 260
+
+static inline int file_attr_to_st_mode (DWORD attr)
+{
+	int fMode = S_IREAD;
+	if (attr & FILE_ATTRIBUTE_DIRECTORY)
+		fMode |= S_IFDIR;
+	else
+		fMode |= S_IFREG;
+	if (!(attr & FILE_ATTRIBUTE_READONLY))
+		fMode |= S_IWRITE;
+	return fMode;
+}
+
+static inline int get_file_attr(const char *fname, WIN32_FILE_ATTRIBUTE_DATA *fdata)
+{
+	if (GetFileAttributesExA(fname, GetFileExInfoStandard, fdata))
+		return 0;
+
+	switch (GetLastError()) {
+	case ERROR_ACCESS_DENIED:
+	case ERROR_SHARING_VIOLATION:
+	case ERROR_LOCK_VIOLATION:
+	case ERROR_SHARING_BUFFER_EXCEEDED:
+		return EACCES;
+	case ERROR_BUFFER_OVERFLOW:
+		return ENAMETOOLONG;
+	case ERROR_NOT_ENOUGH_MEMORY:
+		return ENOMEM;
+	default:
+		return ENOENT;
+	}
+}
+
+static inline time_t filetime_to_time_t(const FILETIME *ft)
+{
+	long long winTime = ((long long)ft->dwHighDateTime << 32) + ft->dwLowDateTime;
+	winTime -= 116444736000000000LL; /* Windows to Unix Epoch conversion */
+	winTime /= 10000000;		 /* Nano to seconds resolution */
+	return (time_t)winTime;
+}
+
+/* We keep the do_lstat code in a separate function to avoid recursion.
+ * When a path ends with a slash, the stat will fail with ENOENT. In
+ * this case, we strip the trailing slashes and stat again.
+ */
+static int do_lstat(const char *file_name, struct stat *buf)
+{
+	WIN32_FILE_ATTRIBUTE_DATA fdata;
+
+	if (!(errno = get_file_attr(file_name, &fdata))) {
+		buf->st_ino = 0;
+		buf->st_gid = 0;
+		buf->st_uid = 0;
+		buf->st_nlink = 1;
+		buf->st_mode = file_attr_to_st_mode(fdata.dwFileAttributes);
+		buf->st_size = fdata.nFileSizeLow; /* Can't use nFileSizeHigh, since it's not a stat64 */
+		buf->st_dev = buf->st_rdev = 0; /* not used by Git */
+		buf->st_atime = filetime_to_time_t(&(fdata.ftLastAccessTime));
+		buf->st_mtime = filetime_to_time_t(&(fdata.ftLastWriteTime));
+		buf->st_ctime = filetime_to_time_t(&(fdata.ftCreationTime));
+		return 0;
+	}
+	return -1;
+}
+
+/* We provide our own lstat/fstat functions, since the provided
+ * lstat/fstat functions are so slow. These stat functions are
+ * tailored for Git's usage (read: fast), and are not meant to be
+ * complete. Note that Git stat()s are redirected to mingw_lstat()
+ * too, since Windows doesn't really handle symlinks that well.
+ */
+int mingw_lstat(const char *file_name, struct stat *buf)
+{
+	int namelen;
+	static char alt_name[PATH_MAX];
+
+	if (!do_lstat(file_name, buf))
+		return 0;
+
+	/* if file_name ended in a '/', Windows returned ENOENT;
+	 * try again without trailing slashes
+	 */
+	if (errno != ENOENT)
+		return -1;
+
+	namelen = strlen(file_name);
+	if (namelen && file_name[namelen-1] != '/')
+		return -1;
+	while (namelen && file_name[namelen-1] == '/')
+		--namelen;
+	if (!namelen || namelen >= PATH_MAX)
+		return -1;
+
+	memcpy(alt_name, file_name, namelen);
+	alt_name[namelen] = 0;
+	return do_lstat(alt_name, buf);
+}
+
+#undef fstat
+int mingw_fstat(int fd, struct stat *buf)
+{
+	HANDLE fh = (HANDLE)_get_osfhandle(fd);
+	BY_HANDLE_FILE_INFORMATION fdata;
+
+	if (fh == INVALID_HANDLE_VALUE) {
+		errno = EBADF;
+		return -1;
+	}
+	/* direct non-file handles to MS's fstat() */
+	if (GetFileType(fh) != FILE_TYPE_DISK)
+		return fstat(fd, buf);
+
+	if (GetFileInformationByHandle(fh, &fdata)) {
+		buf->st_ino = 0;
+		buf->st_gid = 0;
+		buf->st_uid = 0;
+		buf->st_nlink = 1;
+		buf->st_mode = file_attr_to_st_mode(fdata.dwFileAttributes);
+		buf->st_size = fdata.nFileSizeLow; /* Can't use nFileSizeHigh, since it's not a stat64 */
+		buf->st_dev = buf->st_rdev = 0; /* not used by Git */
+		buf->st_atime = filetime_to_time_t(&(fdata.ftLastAccessTime));
+		buf->st_mtime = filetime_to_time_t(&(fdata.ftLastWriteTime));
+		buf->st_ctime = filetime_to_time_t(&(fdata.ftCreationTime));
+		return 0;
+	}
+	errno = EBADF;
+	return -1;
+}
+
+#else
+#define HINT (void)0
+#endif
+
+int main(int argc, char**argv)
+{
+	int i;
+	int err = 0;
+	HINT;
+	for (i = 1; i < argc; i++)
+	{
+		struct stat st;
+		if (stat(argv[i], &st)) {
+			perror(argv[i]);
+			err = 1;
+			continue;
+		}
+		printf("%s: %s\n", argv[i], ctime(&st.st_mtime));
+	}
+	return err;
+}