llseek.c revision ce5bc5c878a8e1b4485ea9a051628a08699aad02
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#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#include "et/com_err.h" 29#include "ext2fs/ext2_io.h" 30 31#ifdef __linux__ 32 33#if defined(HAVE_LSEEK64) && defined(HAVE_LSEEK64_PROTOTYPE) 34 35#define my_llseek lseek64 36 37#else 38#if defined(HAVE_LLSEEK) 39#include <syscall.h> 40 41#ifndef HAVE_LLSEEK_PROTOTYPE 42extern long long llseek (int fd, long long offset, int origin); 43#endif 44 45#define my_llseek llseek 46 47#else /* ! HAVE_LLSEEK */ 48 49#if SIZEOF_LONG == SIZEOF_LONG_LONG 50 51#define my_llseek lseek 52 53#else /* SIZEOF_LONG != SIZEOF_LONG_LONG */ 54 55#include <linux/unistd.h> 56 57#ifndef __NR__llseek 58#define __NR__llseek 140 59#endif 60 61#ifndef __i386__ 62static int _llseek (unsigned int, unsigned long, 63 unsigned long, ext2_loff_t *, unsigned int); 64 65static _syscall5(int,_llseek,unsigned int,fd,unsigned long,offset_high, 66 unsigned long, offset_low,ext2_loff_t *,result, 67 unsigned int, origin) 68#endif 69 70static ext2_loff_t my_llseek (int fd, ext2_loff_t offset, int origin) 71{ 72 ext2_loff_t result; 73 int retval; 74 75#ifndef __i386__ 76 retval = _llseek(fd, ((unsigned long long) offset) >> 32, 77#else 78 retval = syscall(__NR__llseek, fd, (unsigned long long) (offset >> 32), 79#endif 80 ((unsigned long long) offset) & 0xffffffff, 81 &result, origin); 82 return (retval == -1 ? (ext2_loff_t) retval : result); 83} 84 85#endif /* SIZE_LONG == SIZEOF_LONG_LONG */ 86 87#endif /* HAVE_LLSEEK */ 88#endif /* defined(HAVE_LSEEK64) && defined(HAVE_LSEEK64_PROTOTYPE) */ 89 90ext2_loff_t ext2fs_llseek (int fd, ext2_loff_t offset, int origin) 91{ 92#if SIZEOF_OFF_T >= SIZEOF_LONG_LONG 93 return my_llseek (fd, offset, origin); 94#else 95 ext2_loff_t result; 96 static int do_compat = 0; 97 98 if (do_compat) 99 goto fallback; 100 101 result = my_llseek (fd, offset, origin); 102 if (result == -1 && errno == ENOSYS) { 103 /* 104 * Just in case this code runs on top of an old kernel 105 * which does not support the llseek system call 106 */ 107 do_compat++; 108 fallback: 109 if (offset < ((ext2_loff_t) 1 << ((sizeof(off_t)*8) -1))) 110 return lseek(fd, (off_t) offset, origin); 111 errno = EINVAL; 112 return -1; 113 } 114 return result; 115#endif 116} 117 118#else /* !linux */ 119 120#ifndef EINVAL 121#define EINVAL EXT2_ET_INVALID_ARGUMENT 122#endif 123 124ext2_loff_t ext2fs_llseek (int fd, ext2_loff_t offset, int origin) 125{ 126#if defined(HAVE_LSEEK64) && defined(HAVE_LSEEK64_PROTOTYPE) 127 return lseek64 (fd, offset, origin); 128#else 129 if ((sizeof(off_t) < sizeof(ext2_loff_t)) && 130 (offset >= ((ext2_loff_t) 1 << ((sizeof(off_t)*8) -1)))) { 131 errno = EINVAL; 132 return -1; 133 } 134 return lseek (fd, (off_t) offset, origin); 135#endif 136} 137 138#endif /* linux */ 139 140 141