62 lines
1.3 KiB
C
62 lines
1.3 KiB
C
/* read for MMIXware.
|
|
|
|
Copyright (C) 2001, 2023 Hans-Peter Nilsson
|
|
|
|
Permission to use, copy, modify, and distribute this software is
|
|
freely granted, provided that the above copyright notice, this notice
|
|
and the following disclaimer are preserved with no changes.
|
|
|
|
THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
|
|
IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
|
|
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
|
|
PURPOSE. */
|
|
|
|
#include <_ansi.h>
|
|
#include <sys/types.h>
|
|
#include <sys/stat.h>
|
|
#include "sys/syscall.h"
|
|
#include <errno.h>
|
|
|
|
int
|
|
_read (int file,
|
|
void *ptr,
|
|
size_t len)
|
|
{
|
|
long ret;
|
|
|
|
if ((unsigned int) file >= 32 || _MMIX_allocated_filehandle[file] == 0)
|
|
{
|
|
errno = EBADF;
|
|
return -1;
|
|
}
|
|
|
|
if (isatty(file))
|
|
{
|
|
ret = TRAP3f (SYS_Fgets, file, ptr, len);
|
|
|
|
if (ret == -1)
|
|
return 0;
|
|
|
|
return ret;
|
|
}
|
|
|
|
ret = TRAP3f (SYS_Fread, file, ptr, len);
|
|
|
|
/* Map the return codes:
|
|
-1-len: an error. We return -1.
|
|
0: success. We return len.
|
|
n-len: end-of-file after n chars read. We return n. */
|
|
if (ret == 0)
|
|
return len;
|
|
|
|
if (ret == -1 - (long) len)
|
|
{
|
|
/* We don't know the nature of the failure, so this is an
|
|
approximation. */
|
|
errno = EIO;
|
|
return -1;
|
|
}
|
|
|
|
return ret + len;
|
|
}
|