/* Copyright (c) 2017 Facebook
   *
   * This program is free software; you can redistribute it and/or
   * modify it under the terms of version 2 of the GNU General Public
   * License as published by the Free Software Foundation.
   */
  #include <stdio.h>
  #include <unistd.h>
  #include <fcntl.h>
  #include <stdlib.h>
  #include <signal.h>
  #include <linux/bpf.h>
  #include <string.h>
  #include <linux/perf_event.h>
  #include <errno.h>
  #include <assert.h>
  #include <stdbool.h>
  #include <sys/resource.h>
  #include "libbpf.h"
  #include "bpf_load.h"
  
  /* This program verifies bpf attachment to tracepoint sys_enter_* and sys_exit_*.
   * This requires kernel CONFIG_FTRACE_SYSCALLS to be set.
   */
  
  static void verify_map(int map_id)
  {
  	__u32 key = 0;
  	__u32 val;
  
  	if (bpf_map_lookup_elem(map_id, &key, &val) != 0) {
  		fprintf(stderr, "map_lookup failed: %s
  ", strerror(errno));
  		return;
  	}
  	if (val == 0)
  		fprintf(stderr, "failed: map #%d returns value 0
  ", map_id);
  }
  
  int main(int argc, char **argv)
  {
  	struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
  	char filename[256];
  	int fd;
  
  	setrlimit(RLIMIT_MEMLOCK, &r);
  	snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
  
  	if (load_bpf_file(filename)) {
  		fprintf(stderr, "%s", bpf_log_buf);
  		return 1;
  	}
  
  	/* current load_bpf_file has perf_event_open default pid = -1
  	 * and cpu = 0, which permits attached bpf execution on
  	 * all cpus for all pid's. bpf program execution ignores
  	 * cpu affinity.
  	 */
  	/* trigger some "open" operations */
  	fd = open(filename, O_RDONLY);
  	if (fd < 0) {
  		fprintf(stderr, "open failed: %s
  ", strerror(errno));
  		return 1;
  	}
  	close(fd);
  
  	/* verify the map */
  	verify_map(map_fd[0]);
  	verify_map(map_fd[1]);
  
  	return 0;
  }