shlibs/blkid/src/llseek.c

   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) || defined(__UCLIBC__)
  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