samples/bpf/tracex5_user.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <stdio.h>
   3 #include <linux/bpf.h>
   4 #include <unistd.h>
   5 #include <linux/filter.h>
   6 #include <linux/seccomp.h>
   7 #include <sys/prctl.h>
   8 #include "libbpf.h"
   9 #include "bpf_load.h"
  10 #include <sys/resource.h>
  11
  12 /* install fake seccomp program to enable seccomp code path inside the kernel,
  13  * so that our kprobe attached to seccomp_phase1() can be triggered
  14  */
  15 static void install_accept_all_seccomp(void)
  16 {
  17         struct sock_filter filter[] = {
  18                 BPF_STMT(BPF_RET+BPF_K, SECCOMP_RET_ALLOW),
  19         };
  20         struct sock_fprog prog = {
  21                 .len = (unsigned short)(sizeof(filter)/sizeof(filter[0])),
  22                 .filter = filter,
  23         };
  24         if (prctl(PR_SET_SECCOMP, 2, &prog))
  25                 perror("prctl");
  26 }
  27
  28 int main(int ac, char **argv)
  29 {
  30         FILE *f;
  31         char filename[256];
  32         struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
  33
  34         snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
  35         setrlimit(RLIMIT_MEMLOCK, &r);
  36
  37         if (load_bpf_file(filename)) {
  38                 printf("%s", bpf_log_buf);
  39                 return 1;
  40         }
  41
  42         install_accept_all_seccomp();
  43
  44         f = popen("dd if=/dev/zero of=/dev/null count=5", "r");
  45         (void) f;
  46
  47         read_trace_pipe();
  48
  49         return 0;
  50 }