LXR linux/samples/bpf/tracex5

   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
  10/* install fake seccomp program to enable seccomp code path inside the kernel,
  11 * so that our kprobe attached to seccomp_phase1() can be triggered
  12 */
  13static void install_accept_all_seccomp(void)
  14{
  15        struct sock_filter filter[] = {
  16                BPF_STMT(BPF_RET+BPF_K, SECCOMP_RET_ALLOW),
  17        };
  18        struct sock_fprog prog = {
  19                .len = (unsigned short)(sizeof(filter)/sizeof(filter[0])),
  20                .filter = filter,
  21        };
  22        if (prctl(PR_SET_SECCOMP, 2, &prog))
  23                perror("prctl");
  24}
  25
  26int main(int ac, char **argv)
  27{
  28        FILE *f;
  29        char filename[256];
  30
  31        snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
  32
  33        if (load_bpf_file(filename)) {
  34                printf("%s", bpf_log_buf);
  35                return 1;
  36        }
  37
  38        install_accept_all_seccomp();
  39
  40        f = popen("dd if=/dev/zero of=/dev/null count=5", "r");
  41        (void) f;
  42
  43        read_trace_pipe();
  44
  45        return 0;
  46}
  47