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 GNU Library
8 * General Public License, version 2.
9 * %End-Header%
10 */
11
12 #ifndef _LARGEFILE_SOURCE
13 #define _LARGEFILE_SOURCE
14 #endif
15 #ifndef _LARGEFILE64_SOURCE
16 #define _LARGEFILE64_SOURCE
17 #endif
18
19 #include "config.h"
20 #if HAVE_SYS_TYPES_H
21 #include <sys/types.h>
22 #endif
23
24 #if HAVE_ERRNO_H
25 #include <errno.h>
26 #endif
27 #if HAVE_UNISTD_H
28 #include <unistd.h>
29 #endif
30 #ifdef __MSDOS__
31 #include <io.h>
32 #endif
33 #include "et/com_err.h"
34 #include "ext2fs/ext2_io.h"
35
36 #ifdef __linux__
37
38 #if defined(HAVE_LSEEK64) && defined(HAVE_LSEEK64_PROTOTYPE)
39
40 #define my_llseek lseek64
41
42 #else
43 #if defined(HAVE_LLSEEK)
44 #include <sys/syscall.h>
45
46 #ifndef HAVE_LLSEEK_PROTOTYPE
47 extern long long llseek (int fd, long long offset, int origin);
48 #endif
49
50 #define my_llseek llseek
51
52 #else /* ! HAVE_LLSEEK */
53
54 #if SIZEOF_LONG == SIZEOF_LONG_LONG
55
56 #define my_llseek lseek
57
58 #else /* SIZEOF_LONG != SIZEOF_LONG_LONG */
59
60 #include <linux/unistd.h>
61
62 #ifndef __NR__llseek
63 #define __NR__llseek 140
64 #endif
65
66 #ifndef __i386__
67 static int _llseek (unsigned int, unsigned long,
68 unsigned long, ext2_loff_t *, unsigned int);
69
_syscall5(int,_llseek,unsigned int,fd,unsigned long,offset_high,unsigned long,offset_low,ext2_loff_t *,result,unsigned int,origin)70 static _syscall5(int,_llseek,unsigned int,fd,unsigned long,offset_high,
71 unsigned long, offset_low,ext2_loff_t *,result,
72 unsigned int, origin)
73 #endif
74
75 static ext2_loff_t my_llseek (int fd, ext2_loff_t offset, int origin)
76 {
77 ext2_loff_t result;
78 int retval;
79
80 #ifndef __i386__
81 retval = _llseek(fd, ((unsigned long long) offset) >> 32,
82 #else
83 retval = syscall(__NR__llseek, fd, (unsigned long long) (offset >> 32),
84 #endif
85 ((unsigned long long) offset) & 0xffffffff,
86 &result, origin);
87 return (retval == -1 ? (ext2_loff_t) retval : result);
88 }
89
90 #endif /* SIZE_LONG == SIZEOF_LONG_LONG */
91
92 #endif /* HAVE_LLSEEK */
93 #endif /* defined(HAVE_LSEEK64) && defined(HAVE_LSEEK64_PROTOTYPE) */
94
ext2fs_llseek(int fd,ext2_loff_t offset,int origin)95 ext2_loff_t ext2fs_llseek (int fd, ext2_loff_t offset, int origin)
96 {
97 #if SIZEOF_OFF_T >= SIZEOF_LONG_LONG
98 return my_llseek (fd, offset, origin);
99 #else
100 ext2_loff_t result;
101 static int do_compat = 0;
102
103 if (do_compat)
104 goto fallback;
105
106 result = my_llseek (fd, offset, origin);
107 if (result == -1 && errno == ENOSYS) {
108 /*
109 * Just in case this code runs on top of an old kernel
110 * which does not support the llseek system call
111 */
112 do_compat++;
113 fallback:
114 if (offset < ((ext2_loff_t) 1 << ((sizeof(off_t)*8) -1)))
115 return lseek(fd, (off_t) offset, origin);
116 errno = EINVAL;
117 return -1;
118 }
119 return result;
120 #endif
121 }
122
123 #else /* !linux */
124
125 #ifndef EINVAL
126 #define EINVAL EXT2_ET_INVALID_ARGUMENT
127 #endif
128
ext2fs_llseek(int fd,ext2_loff_t offset,int origin)129 ext2_loff_t ext2fs_llseek (int fd, ext2_loff_t offset, int origin)
130 {
131 #if defined(HAVE_LSEEK64) && defined(HAVE_LSEEK64_PROTOTYPE)
132 return lseek64 (fd, offset, origin);
133 #else
134 if ((sizeof(off_t) < sizeof(ext2_loff_t)) &&
135 (offset >= ((ext2_loff_t) 1 << ((sizeof(off_t)*8) -1)))) {
136 errno = EINVAL;
137 return -1;
138 }
139 return lseek (fd, (off_t) offset, origin);
140 #endif
141 }
142
143 #endif /* linux */
144
145
146