samples/bpf/tracex5_user.c

   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 }