LXR linux/samples/bpf/tracex5

   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 */
  15static 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
  28int 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}
  51