xref: /linux/samples/bpf/tracex5_user.c (revision f3a8b6645dc2e60d11f20c1c23afd964ff4e55ae)
1 #include <stdio.h>
2 #include <linux/bpf.h>
3 #include <unistd.h>
4 #include <linux/filter.h>
5 #include <linux/seccomp.h>
6 #include <sys/prctl.h>
7 #include "libbpf.h"
8 #include "bpf_load.h"
9 #include <sys/resource.h>
10 
11 /* install fake seccomp program to enable seccomp code path inside the kernel,
12  * so that our kprobe attached to seccomp_phase1() can be triggered
13  */
14 static void install_accept_all_seccomp(void)
15 {
16 	struct sock_filter filter[] = {
17 		BPF_STMT(BPF_RET+BPF_K, SECCOMP_RET_ALLOW),
18 	};
19 	struct sock_fprog prog = {
20 		.len = (unsigned short)(sizeof(filter)/sizeof(filter[0])),
21 		.filter = filter,
22 	};
23 	if (prctl(PR_SET_SECCOMP, 2, &prog))
24 		perror("prctl");
25 }
26 
27 int main(int ac, char **argv)
28 {
29 	FILE *f;
30 	char filename[256];
31 	struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
32 
33 	snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
34 	setrlimit(RLIMIT_MEMLOCK, &r);
35 
36 	if (load_bpf_file(filename)) {
37 		printf("%s", bpf_log_buf);
38 		return 1;
39 	}
40 
41 	install_accept_all_seccomp();
42 
43 	f = popen("dd if=/dev/zero of=/dev/null count=5", "r");
44 	(void) f;
45 
46 	read_trace_pipe();
47 
48 	return 0;
49 }
50