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 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 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 125 126 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
