blob: 9f863cded6e3854add36de3a196318ff06fc0b68 (
plain)
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
|
/* sbrk support */
/* The current plan is to have one sbrk handler for all cpus.
Hence use `asm' for each global variable here to avoid the cpu prefix.
We can't intrude on the user's namespace (another reason to use asm). */
#include <sys/types.h>
#include <sys/syscall.h>
#include <errno.h>
#include <stddef.h>
/* These variables are publicly accessible for debugging purposes.
The user is also free to set sbrk_size to something different.
See mem-layout.c. */
extern int sbrk_size asm ("sbrk_size");
caddr_t sbrk_start asm ("sbrk_start");
caddr_t sbrk_loc asm ("sbrk_loc");
/*caddr_t _sbrk_r (struct _reent *, size_t) asm ("__sbrk_r");*/
/* FIXME: We need a semaphore here. */
caddr_t
_sbrk_r (struct _reent *r, size_t nbytes)
{
caddr_t result;
if (
/* Ensure we don't underflow. */
sbrk_loc + nbytes < sbrk_start
/* Ensure we don't overflow. */
|| sbrk_loc + nbytes > sbrk_start + sbrk_size)
{
errno = ENOMEM;
return ((caddr_t) -1);
}
result = sbrk_loc;
sbrk_loc += nbytes;
return result;
}
|
