1 /* An lseek() function that detects pipes.
2 Copyright (C) 2007, 2009-2017 Free Software Foundation, Inc.
3
4 This program is free software; you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation; either version 3, or (at your option)
7 any later version.
8
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
13
14 You should have received a copy of the GNU General Public License along
15 with this program; if not, see <http://www.gnu.org/licenses/>. */
16
17 #include <config.h>
18
19 /* Specification. */
20 #include <unistd.h>
21
22 #if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
23 /* Windows platforms. */
24 /* Get GetFileType. */
25 # include <windows.h>
26 /* Get _get_osfhandle. */
27 # include "msvc-nothrow.h"
28 #else
29 # include <sys/stat.h>
30 #endif
31 #include <errno.h>
32
33 #undef lseek
34
35 off_t
rpl_lseek(int fd,off_t offset,int whence)36 rpl_lseek (int fd, off_t offset, int whence)
37 {
38 #if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
39 /* mingw lseek mistakenly succeeds on pipes, sockets, and terminals. */
40 HANDLE h = (HANDLE) _get_osfhandle (fd);
41 if (h == INVALID_HANDLE_VALUE)
42 {
43 errno = EBADF;
44 return -1;
45 }
46 if (GetFileType (h) != FILE_TYPE_DISK)
47 {
48 errno = ESPIPE;
49 return -1;
50 }
51 #else
52 /* BeOS lseek mistakenly succeeds on pipes... */
53 struct stat statbuf;
54 if (fstat (fd, &statbuf) < 0)
55 return -1;
56 if (!S_ISREG (statbuf.st_mode))
57 {
58 errno = ESPIPE;
59 return -1;
60 }
61 #endif
62 #if _GL_WINDOWS_64_BIT_OFF_T
63 return _lseeki64 (fd, offset, whence);
64 #else
65 return lseek (fd, offset, whence);
66 #endif
67 }
68