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 <uapi/linux/bpf.h>
10#include <bpf/bpf_helpers.h>
11#include <bpf/bpf_tracing.h>
12
13#define _(P)                                                                   \
14	({                                                                     \
15		typeof(P) val = 0;                                             \
16		bpf_probe_read_kernel(&val, sizeof(val), &(P));                \
17		val;                                                           \
18	})
19
20SEC("kprobe/__set_task_comm")
21int prog(struct pt_regs *ctx)
22{
23	struct signal_struct *signal;
24	struct task_struct *tsk;
25	char oldcomm[16] = {};
26	char newcomm[16] = {};
27	u16 oom_score_adj;
28	u32 pid;
29
30	tsk = (void *)PT_REGS_PARM1(ctx);
31
32	pid = _(tsk->pid);
33	bpf_probe_read_kernel(oldcomm, sizeof(oldcomm), &tsk->comm);
34	bpf_probe_read_kernel(newcomm, sizeof(newcomm),
35			      (void *)PT_REGS_PARM2(ctx));
36	signal = _(tsk->signal);
37	oom_score_adj = _(signal->oom_score_adj);
38	return 0;
39}
40
41SEC("kprobe/urandom_read")
42int prog2(struct pt_regs *ctx)
43{
44	return 0;
45}
46
47char _license[] SEC("license") = "GPL";
48u32 _version SEC("version") = LINUX_VERSION_CODE;