lib/ext2fs/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 GNU Public
   8  * 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 #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
  42 extern 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 defined(__alpha__) || defined (__ia64__)
  50
  51 #define llseek lseek
  52
  53 #else /* !__alpha__ && !__ia64__*/
  54
  55 #include <linux/unistd.h>
  56
  57 #ifndef __NR__llseek
  58 #define __NR__llseek            140
  59 #endif
  60
  61 #ifndef __i386__
  62 static int _llseek (unsigned int, unsigned long,
  63                    unsigned long, ext2_loff_t *, unsigned int);
  64
  65 static _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
  70 static 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  /* __alpha__ || __ia64__ */
  86
  87 #endif /* HAVE_LLSEEK */
  88 #endif /* defined(HAVE_LSEEK64) && defined(HAVE_LSEEK64_PROTOTYPE) */
  89
  90 ext2_loff_t ext2fs_llseek (int fd, ext2_loff_t offset, int origin)
  91 {
  92         ext2_loff_t result;
  93         static int do_compat = 0;
  94
  95         if ((sizeof(off_t) >= sizeof(ext2_loff_t)) ||
  96             (offset < ((ext2_loff_t) 1 << ((sizeof(off_t)*8) -1))))
  97                 return lseek(fd, (off_t) offset, origin);
  98
  99         if (do_compat) {
 100                 errno = EINVAL;
 101                 return -1;
 102         }
 103
 104         result = my_llseek (fd, offset, origin);
 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 = EINVAL;
 112         }
 113         return result;
 114 }
 115
 116 #else /* !linux */
 117
 118 #ifndef EINVAL
 119 #define EINVAL EXT2_ET_INVALID_ARGUMENT
 120 #endif
 121
 122 ext2_loff_t ext2fs_llseek (int fd, ext2_loff_t offset, int origin)
 123 {
 124         if ((sizeof(off_t) < sizeof(ext2_loff_t)) &&
 125             (offset >= ((ext2_loff_t) 1 << ((sizeof(off_t)*8) -1)))) {
 126                 errno = EINVAL;
 127                 return -1;
 128         }
 129         return lseek (fd, (off_t) offset, origin);
 130 }
 131
 132 #endif  /* linux */
 133
 134