/* Copyright (c) 2016 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 <linux/version.h>
  #include <linux/ptrace.h>
  #include <uapi/linux/bpf.h>
  #include "bpf_helpers.h"
  
  #define _(P) ({typeof(P) val = 0; bpf_probe_read(&val, sizeof(val), &P); val;})
  
  SEC("kprobe/__set_task_comm")
  int prog(struct pt_regs *ctx)
  {
  	struct signal_struct *signal;
  	struct task_struct *tsk;
  	char oldcomm[16] = {};
  	char newcomm[16] = {};
  	u16 oom_score_adj;
  	u32 pid;
  
  	tsk = (void *)PT_REGS_PARM1(ctx);
  
  	pid = _(tsk->pid);
  	bpf_probe_read(oldcomm, sizeof(oldcomm), &tsk->comm);
  	bpf_probe_read(newcomm, sizeof(newcomm), (void *)PT_REGS_PARM2(ctx));
  	signal = _(tsk->signal);
  	oom_score_adj = _(signal->oom_score_adj);
  	return 0;
  }
  
  SEC("kprobe/urandom_read")
  int prog2(struct pt_regs *ctx)
  {
  	return 0;
  }
  
  char _license[] SEC("license") = "GPL";
  u32 _version SEC("version") = LINUX_VERSION_CODE;