1 /* -*- mode: C; c-basic-offset: 3; -*- */
2
3 #include <assert.h>
4 #include <elf.h>
5 #include <stdio.h>
6 #include <stdlib.h>
7 #include <string.h>
8 #include <unistd.h>
9
10 #include <sys/ptrace.h>
11 #include <sys/types.h>
12 #include <sys/uio.h>
13 #include <sys/user.h>
14 #include <sys/wait.h>
15
16 static int
err_out(const char * msg)17 err_out(const char *msg)
18 {
19 perror(msg);
20 return 1;
21 }
22
23 static int
non_empty(const char * buf,size_t len)24 non_empty(const char *buf, size_t len)
25 {
26 size_t i;
27 int c = 0;
28 volatile const char *p = buf;
29
30 for (i = 0; i != len; i++)
31 c |= p[i];
32 return c;
33 }
34
35 static int
do_child(void)36 do_child(void)
37 {
38 if (ptrace(PTRACE_TRACEME, 0, NULL, NULL) == -1)
39 return err_out("ptrace traceme");
40 raise(SIGUSR1);
41 return 0;
42 }
43
44 int
main(void)45 main(void)
46 {
47 char buf[1024];
48 struct iovec iov;
49 pid_t cpid, pid;
50 int status;
51
52 cpid = fork();
53 if (cpid == -1)
54 return err_out("fork");
55 if (cpid == 0)
56 return do_child();
57
58 pid = wait(&status);
59 if (pid == -1)
60 return err_out("wait");
61
62 /* Intentionally provide an uninitialized buffer to ptrace. */
63 iov.iov_len = sizeof(buf);
64 iov.iov_base = buf;
65 if (ptrace(0x4204, cpid, NT_PRSTATUS, &iov) == -1)
66 return err_out("ptrace getregset");
67
68 assert(iov.iov_base == buf);
69 assert(iov.iov_len > 0 && iov.iov_len < sizeof(buf));
70
71 /* We're assuming here that NT_PRSTATUS never contains
72 all-zeros. */
73 assert(non_empty(buf, iov.iov_len));
74 puts("OK");
75 return 0;
76 }
77