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
41 extern 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__
61 static int _llseek(unsigned int, unsigned long, unsigned long,
62 blkid_loff_t *, unsigned int);
63
_syscall5(int,_llseek,unsigned int,fd,unsigned long,offset_high,unsigned long,offset_low,blkid_loff_t *,result,unsigned int,origin)64 static _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
69 static 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
blkid_llseek(int fd,blkid_loff_t offset,int whence)90 blkid_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
blkid_llseek(int fd,blkid_loff_t offset,int origin)126 blkid_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