34 lines
789 B
C
34 lines
789 B
C
|
/* Utility function for tests that try to break system calls by
|
||
|
|
passing them data that crosses from one virtual page to
|
||
|
|
another. */
|
||
|
|
|
||
|
|
#include <inttypes.h>
|
||
|
|
#include <round.h>
|
||
|
|
#include <string.h>
|
||
|
|
#include "tests/userprog/boundary.h"
|
||
|
|
|
||
|
|
static char dst[8192];
|
||
|
|
|
||
|
|
/* Returns the beginning of a page. There are at least 2048
|
||
|
|
modifiable bytes on either side of the pointer returned. */
|
||
|
|
void *
|
||
|
|
get_boundary_area (void)
|
||
|
|
{
|
||
|
|
char *p = (char *) ROUND_UP ((uintptr_t) dst, 4096);
|
||
|
|
if (p - dst < 2048)
|
||
|
|
p += 4096;
|
||
|
|
return p;
|
||
|
|
}
|
||
|
|
|
||
|
|
/* Returns a copy of SRC split across the boundary between two
|
||
|
|
pages. */
|
||
|
|
char *
|
||
|
|
copy_string_across_boundary (const char *src)
|
||
|
|
{
|
||
|
|
char *p = get_boundary_area ();
|
||
|
|
p -= strlen (src) < 4096 ? strlen (src) / 2 : 4096;
|
||
|
|
strlcpy (p, src, 4096);
|
||
|
|
return p;
|
||
|
|
}
|
||
|
|
|