1 /* Emulate fsync on platforms that lack it, primarily Windows and
2 cross-compilers like MinGW.
3
4 This is derived from sqlite3 sources.
5 https://www.sqlite.org/src/finfo?name=src/os_win.c
6 https://www.sqlite.org/copyright.html
7
8 Written by Richard W.M. Jones <rjones.at.redhat.com>
9
10 Copyright (C) 2008-2023 Free Software Foundation, Inc.
11
12 This file is free software: you can redistribute it and/or modify
13 it under the terms of the GNU Lesser General Public License as
14 published by the Free Software Foundation; either version 2.1 of the
15 License, or (at your option) any later version.
16
17 This file is distributed in the hope that it will be useful,
18 but WITHOUT ANY WARRANTY; without even the implied warranty of
19 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 GNU Lesser General Public License for more details.
21
22 You should have received a copy of the GNU Lesser General Public License
23 along with this program. If not, see <https://www.gnu.org/licenses/>. */
24
25 #include <config.h>
26 #include <unistd.h>
27
28 #if defined _WIN32 && ! defined __CYGWIN__
29
30 /* FlushFileBuffers */
31 # define WIN32_LEAN_AND_MEAN
32 # include <windows.h>
33
34 # include <errno.h>
35
36 /* Get _get_osfhandle. */
37 # if GNULIB_MSVC_NOTHROW
38 # include "msvc-nothrow.h"
39 # else
40 # include <io.h>
41 # endif
42
43 int
44 fsync (int fd)
45 {
46 HANDLE h = (HANDLE) _get_osfhandle (fd);
47 DWORD err;
48
49 if (h == INVALID_HANDLE_VALUE)
50 {
51 errno = EBADF;
52 return -1;
53 }
54
55 if (!FlushFileBuffers (h))
56 {
57 /* Translate some Windows errors into rough approximations of Unix
58 * errors. MSDN is useless as usual - in this case it doesn't
59 * document the full range of errors.
60 */
61 err = GetLastError ();
62 switch (err)
63 {
64 case ERROR_ACCESS_DENIED:
65 /* For a read-only handle, fsync should succeed, even though we have
66 no way to sync the access-time changes. */
67 return 0;
68
69 /* eg. Trying to fsync a tty. */
70 case ERROR_INVALID_HANDLE:
71 errno = EINVAL;
72 break;
73
74 default:
75 errno = EIO;
76 }
77 return -1;
78 }
79
80 return 0;
81 }
82
83 #else /* !Windows */
84
85 # error "This platform lacks fsync function, and Gnulib doesn't provide a replacement. This is a bug in Gnulib."
86
87 #endif /* !Windows */