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/*
* Eats kernel memory. Lots of it.
*/
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <sys/mman.h>
#include <unistd.h>
#include <test/test.h>
#define PAGE_SIZE 4096
static void eat(void *addr, int *count, int *num)
{
int status;
test_fork_begin()
{
if (*num <= 0)
{
/* Eat the memory until we die */
while (1)
{
char foo = *((char *)addr + ((*count)++ * PAGE_SIZE));
if ((*count & 0x7f) == 0)
{
printf("Ate %d pages\n", *count);
}
}
}
else
{
/* Eat until we have the necessary number of pages */
while (*count < *num)
{
char foo = *((char *)addr + ((*count)++ * PAGE_SIZE));
if ((*count & 0x7f) == 0)
{
printf("Ate %d pages\n", *count);
}
}
}
}
test_fork_end(&status);
if (*num <= 0 && EFAULT != status)
{
fprintf(stderr, "Child process didn't segfault!\n");
exit(1);
}
if (*num < 0)
{
/* Free the required number of pages */
munmap(addr, PAGE_SIZE * (-*num));
printf("Gave back %d pages\n", -*num);
*count += *num;
}
}
#define FLAG_DAEMON "-d"
#define FLAG_INFINITE "-i"
#define FLAG_ITER "-y"
#define FLAG_NUM "-#"
#define OPT_DAEMON 1
#define OPT_INFINITE 2
#define OPT_ITER 4
#define OPT_NUM 8
int parse_args(int argc, char **argv, int *opts, int *iter, int *num)
{
int i;
*opts = *iter = *num = 0;
for (i = 1; i < argc; i++)
{
if (!strcmp(FLAG_DAEMON, argv[i]))
{
*opts |= OPT_DAEMON;
}
else if (!strcmp(FLAG_INFINITE, argv[i]))
{
*opts |= OPT_INFINITE;
}
else if (!strcmp(FLAG_ITER, argv[i]))
{
*opts |= OPT_ITER;
if (++i >= argc ||
(errno = 0, *iter = strtol(argv[i], NULL, 0), 0 != errno))
{
return -1;
}
}
else if (!strcmp(FLAG_NUM, argv[i]))
{
*opts |= OPT_NUM;
if (++i >= argc ||
(errno = 0, *num = strtol(argv[i], NULL, 0), 0 != errno))
{
return -1;
}
}
else
{
return -1;
}
}
return 0;
}
int main(int argc, char **argv)
{
int status;
void *addr;
int *count;
int *opts, *iter, *num;
/* Get our huge mess of space. We map this as a bunch of regions at the
* beginning so that unmapping (above) actually does something. */
if (MAP_FAILED ==
(addr = mmap(NULL, PAGE_SIZE * 10000, PROT_READ | PROT_WRITE,
MAP_SHARED | MAP_ANON, -1, 0)))
{
return 1;
}
int i;
for (i = 0; i < 40; i++)
{
if (MAP_FAILED == mmap((char *)addr + PAGE_SIZE * 25 * i,
PAGE_SIZE * 25, PROT_READ | PROT_WRITE,
MAP_FIXED | MAP_SHARED | MAP_ANON, -1, 0))
{
return 1;
}
}
/* Set the initial count */
count = addr;
*count = 0;
opts = count + 1;
iter = count + 2;
num = count + 3;
if (0 > parse_args(argc, argv, opts, iter, num))
{
fprintf(
stderr,
"USAGE: eatmem [options]\n" FLAG_DAEMON
" run as daemon\n" FLAG_INFINITE
" run forever\n" FLAG_ITER
" [num] number of iterations to yield\n" FLAG_NUM
" [num] number of pages to eat (if negative, to relinquish)\n");
return 1;
}
addr = (char *)addr + PAGE_SIZE;
printf("OM NOM NOM NOM\n");
if (*opts & OPT_DAEMON)
{
if (fork())
{
exit(0);
}
}
eat(addr, count, num);
printf("Ate %d pages in total\n", *count);
if (*opts & OPT_INFINITE)
{
while (1)
{
sched_yield();
}
}
else if (*opts & OPT_ITER)
{
while (--iter)
{
sched_yield();
}
}
printf("Giving memory back now\n");
return 0;
}
|
