$ cat -n ostep/code/intro/mem.c
1 #include <unistd.h>
2 #include <stdio.h>
3 #include <stdlib.h>
4 #include "common.h"
5
6 int main(int argc, char *argv[]) {
7 if (argc != 2) {
8 fprintf(stderr, "usage: mem <value>\n");
9 exit(1);
10 }
11 int *p;
12 p = malloc(sizeof(int));
13 assert(p != NULL);
14 printf("(%d) addr pointed to by p: %p\n", (int) getpid(), p);
15 *p = atoi(argv[1]); // assign value to addr stored in p
16 while (1) {
17 Spin(1);
18 *p = *p + 1;
19 printf("(%d) value of p: %d\n", getpid(), *p);
20 }
21 return 0;
22 }
$ ./mem 10
(3629) addr pointed to by p: 0x55917a0fb260
(3629) value of p: 11
(3629) value of p: 12
(3629) value of p: 13
^C
$
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-
$ ./mem 10 & ./mem 100 &
[1] 3645
[2] 3646
$ (3645) addr pointed to by p: 0x55ae4b29a260
(3646) addr pointed to by p: 0x55a15c730260
(3645) value of p: 11
(3646) value of p: 101
(3645) value of p: 12
(3646) value of p: 102
...
$ setarch $(uname --machine) --addr-no-randomize /bin/bash
$ ./mem 10 & ./mem 100 &
[1] 3680
[2] 3681
$ (3680) addr pointed to by p: 0x555555756260
(3681) addr pointed to by p: 0x555555756260
(3680) value of p: 11
(3681) value of p: 101
(3680) value of p: 12
(3681) value of p: 102
...
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