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
|
/* The kernel call implemented in this file:
* m_type: SYS_SAFEMEMSET
*
* The parameters for this kernel call are:
* SMS_DST dst endpoint
* SMS_GID grant id
* SMS_OFFSET offset within grant
* SMS_PATTERN memset pattern byte
* SMS_BYTES bytes from offset
*/
#include <assert.h>
#include <minix/safecopies.h>
#include "kernel/system.h"
/*===========================================================================*
* do_safememset *
*===========================================================================*/
int do_safememset(struct proc *caller, message *m_ptr) {
/* Implementation of the do_safememset() kernel call */
/* Extract parameters */
endpoint_t dst_endpt = m_ptr->SMS_DST;
endpoint_t caller_endpt = caller->p_endpoint;
cp_grant_id_t grantid = m_ptr->SMS_GID;
vir_bytes g_offset = m_ptr->SMS_OFFSET;
int pattern = m_ptr->SMS_PATTERN;
size_t len = (size_t)m_ptr->SMS_BYTES;
struct proc *dst_p;
endpoint_t new_granter;
static vir_bytes v_offset;
int r;
if (dst_endpt == NONE || caller_endpt == NONE)
return EFAULT;
if (!(dst_p = endpoint_lookup(dst_endpt)))
return EINVAL;
if (!(priv(dst_p) && priv(dst_p)->s_grant_table)) {
printf("safememset: dst %d has no grant table\n", dst_endpt);
return EINVAL;
}
/* Verify permission exists, memset always requires CPF_WRITE */
r = verify_grant(dst_endpt, caller_endpt, grantid, len, CPF_WRITE,
g_offset, &v_offset, &new_granter, NULL);
if (r != OK) {
printf("safememset: grant %d verify failed %d", grantid, r);
return r;
}
return vm_memset(caller, new_granter, v_offset, pattern, len);
}
|
