1/*
2 * llseek.c -- stub calling the llseek system call
3 *
4 * Copyright (C) 1994, 1995, 1996, 1997 Theodore Ts'o.
5 *
6 * %Begin-Header%
7 * This file may be redistributed under the terms of the
8 * GNU Lesser General Public License.
9 * %End-Header%
10 */
11
12#define _LARGEFILE_SOURCE
13#define _LARGEFILE64_SOURCE
14
15#if HAVE_SYS_TYPES_H
16#include <sys/types.h>
17#endif
18
19#if HAVE_ERRNO_H
20#include <errno.h>
21#endif
22#if HAVE_UNISTD_H
23#include <unistd.h>
24#endif
25#ifdef __MSDOS__
26#include <io.h>
27#endif
28
29#include "blkidP.h"
30
31#ifdef __linux__
32
33#if defined(HAVE_LSEEK64) && defined(HAVE_LSEEK64_PROTOTYPE)
34
35#define my_llseek lseek64
36
37#elif defined(HAVE_LLSEEK)
38#include <syscall.h>
39
40#ifndef HAVE_LLSEEK_PROTOTYPE
41extern long long llseek(int fd, long long offset, int origin);
42#endif
43
44#define my_llseek llseek
45
46#else	/* ! HAVE_LLSEEK */
47
48#if SIZEOF_LONG == SIZEOF_LONG_LONG
49
50#define llseek lseek
51
52#else /* SIZEOF_LONG != SIZEOF_LONG_LONG */
53
54#include <linux/unistd.h>
55
56#ifndef __NR__llseek
57#define __NR__llseek            140
58#endif
59
60#ifndef __i386__
61static int _llseek(unsigned int, unsigned long, unsigned long,
62		   blkid_loff_t *, unsigned int);
63
64static _syscall5(int, _llseek, unsigned int, fd, unsigned long, offset_high,
65		 unsigned long, offset_low, blkid_loff_t *, result,
66		 unsigned int, origin)
67#endif
68
69static blkid_loff_t my_llseek(int fd, blkid_loff_t offset, int origin)
70{
71	blkid_loff_t result;
72	int retval;
73
74#ifndef __i386__
75	retval = _llseek(fd, ((unsigned long long) offset) >> 32,
76			 ((unsigned long long)offset) & 0xffffffff,
77			 &result, origin);
78#else
79	retval = syscall(__NR__llseek, fd, ((unsigned long long) offset) >> 32,
80			 ((unsigned long long)offset) & 0xffffffff,
81			 &result, origin);
82#endif
83	return (retval == -1 ? (blkid_loff_t) retval : result);
84}
85
86#endif	/* __alpha__ || __ia64__ */
87
88#endif /* HAVE_LLSEEK */
89
90blkid_loff_t blkid_llseek(int fd, blkid_loff_t offset, int whence)
91{
92	blkid_loff_t result;
93	static int do_compat = 0;
94
95	if ((sizeof(off_t) >= sizeof(blkid_loff_t)) ||
96	    (offset < ((blkid_loff_t) 1 << ((sizeof(off_t)*8) -1))))
97		return lseek(fd, (off_t) offset, whence);
98
99	if (do_compat) {
100		errno = EOVERFLOW;
101		return -1;
102	}
103
104	result = my_llseek(fd, offset, whence);
105	if (result == -1 && errno == ENOSYS) {
106		/*
107		 * Just in case this code runs on top of an old kernel
108		 * which does not support the llseek system call
109		 */
110		do_compat++;
111		errno = EOVERFLOW;
112	}
113	return result;
114}
115
116#else /* !linux */
117
118#ifndef EOVERFLOW
119#ifdef EXT2_ET_INVALID_ARGUMENT
120#define EOVERFLOW EXT2_ET_INVALID_ARGUMENT
121#else
122#define EOVERFLOW 112
123#endif
124#endif
125
126blkid_loff_t blkid_llseek(int fd, blkid_loff_t offset, int origin)
127{
128#if defined(HAVE_LSEEK64) && defined(HAVE_LSEEK64_PROTOTYPE)
129	return lseek64 (fd, offset, origin);
130#else
131	if ((sizeof(off_t) < sizeof(blkid_loff_t)) &&
132	    (offset >= ((blkid_loff_t) 1 << ((sizeof(off_t)*8) - 1)))) {
133		errno = EOVERFLOW;
134		return -1;
135	}
136	return lseek(fd, (off_t) offset, origin);
137#endif
138}
139
140#endif	/* linux */
141
142
143