1/* Copyright (c) 2016 Facebook
 2 *
 3 * This program is free software; you can redistribute it and/or
 4 * modify it under the terms of version 2 of the GNU General Public
 5 * License as published by the Free Software Foundation.
 6 */
 7#include <linux/version.h>
 8#include <linux/ptrace.h>
 9#include <linux/sched.h>
10#include <uapi/linux/bpf.h>
11#include <bpf/bpf_helpers.h>
12#include <bpf/bpf_tracing.h>
13
14#define _(P)                                                                   \
15	({                                                                     \
16		typeof(P) val = 0;                                             \
17		bpf_probe_read_kernel(&val, sizeof(val), &(P));                \
18		val;                                                           \
19	})
20
21SEC("kprobe/__set_task_comm")
22int prog(struct pt_regs *ctx)
23{
24	struct signal_struct *signal;
25	struct task_struct *tsk;
26	char oldcomm[TASK_COMM_LEN] = {};
27	char newcomm[TASK_COMM_LEN] = {};
28	u16 oom_score_adj;
29	u32 pid;
30
31	tsk = (void *)PT_REGS_PARM1(ctx);
32
33	pid = _(tsk->pid);
34	bpf_probe_read_kernel_str(oldcomm, sizeof(oldcomm), &tsk->comm);
35	bpf_probe_read_kernel_str(newcomm, sizeof(newcomm),
36				  (void *)PT_REGS_PARM2(ctx));
37	signal = _(tsk->signal);
38	oom_score_adj = _(signal->oom_score_adj);
39	return 0;
40}
41
42SEC("kprobe/urandom_read")
43int prog2(struct pt_regs *ctx)
44{
45	return 0;
46}
47
48char _license[] SEC("license") = "GPL";
49u32 _version SEC("version") = LINUX_VERSION_CODE;