1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
|
/* 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;
}
|
