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 #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 34 #include "blkidP.h" 35 36 #ifdef __linux__ 37 38 #if defined(HAVE_LSEEK64) && defined(HAVE_LSEEK64_PROTOTYPE) 39 40 #define my_llseek lseek64 41 42 #elif defined(HAVE_LLSEEK) 43 #include <sys/syscall.h> 44 45 #ifndef HAVE_LLSEEK_PROTOTYPE 46 extern long long llseek(int fd, long long offset, int origin); 47 #endif 48 49 #define my_llseek llseek 50 51 #else /* ! HAVE_LLSEEK */ 52 53 #if SIZEOF_LONG == SIZEOF_LONG_LONG 54 55 #define llseek lseek 56 57 #else /* SIZEOF_LONG != SIZEOF_LONG_LONG */ 58 59 #include <linux/unistd.h> 60 61 #ifndef __NR__llseek 62 #define __NR__llseek 140 63 #endif 64 65 #ifndef __i386__ 66 static int _llseek(unsigned int, unsigned long, unsigned long, 67 blkid_loff_t *, unsigned int); 68 69 static _syscall5(int, _llseek, unsigned int, fd, unsigned long, offset_high, 70 unsigned long, offset_low, blkid_loff_t *, result, 71 unsigned int, origin) 72 #endif 73 74 static blkid_loff_t my_llseek(int fd, blkid_loff_t offset, int origin) 75 { 76 blkid_loff_t result; 77 int retval; 78 79 #ifndef __i386__ 80 retval = _llseek(fd, ((unsigned long long) offset) >> 32, 81 ((unsigned long long)offset) & 0xffffffff, 82 &result, origin); 83 #else 84 retval = syscall(__NR__llseek, fd, ((unsigned long long) offset) >> 32, 85 ((unsigned long long)offset) & 0xffffffff, 86 &result, origin); 87 #endif 88 return (retval == -1 ? (blkid_loff_t) retval : result); 89 } 90 91 #endif /* __alpha__ || __ia64__ */ 92 93 #endif /* HAVE_LLSEEK */ 94 95 blkid_loff_t blkid_llseek(int fd, blkid_loff_t offset, int whence) 96 { 97 blkid_loff_t result; 98 static int do_compat = 0; 99 100 if ((sizeof(off_t) >= sizeof(blkid_loff_t)) || 101 (offset < ((blkid_loff_t) 1 << ((sizeof(off_t)*8) -1)))) 102 return lseek(fd, (off_t) offset, whence); 103 104 if (do_compat) { 105 errno = EOVERFLOW; 106 return -1; 107 } 108 109 result = my_llseek(fd, offset, whence); 110 if (result == -1 && errno == ENOSYS) { 111 /* 112 * Just in case this code runs on top of an old kernel 113 * which does not support the llseek system call 114 */ 115 do_compat++; 116 errno = EOVERFLOW; 117 } 118 return result; 119 } 120 121 #else /* !linux */ 122 123 #ifndef EOVERFLOW 124 #ifdef EXT2_ET_INVALID_ARGUMENT 125 #define EOVERFLOW EXT2_ET_INVALID_ARGUMENT 126 #else 127 #define EOVERFLOW 112 128 #endif 129 #endif 130 131 blkid_loff_t blkid_llseek(int fd, blkid_loff_t offset, int origin) 132 { 133 #if defined(HAVE_LSEEK64) && defined(HAVE_LSEEK64_PROTOTYPE) 134 return lseek64 (fd, offset, origin); 135 #else 136 if ((sizeof(off_t) < sizeof(blkid_loff_t)) && 137 (offset >= ((blkid_loff_t) 1 << ((sizeof(off_t)*8) - 1)))) { 138 errno = EOVERFLOW; 139 return -1; 140 } 141 return lseek(fd, (off_t) offset, origin); 142 #endif 143 } 144 145 #endif /* linux */ 146 147 148
