1// SPDX-License-Identifier: GPL-2.0
2/* Copyright (C) 2023. Huawei Technologies Co., Ltd */
3#include <stdbool.h>
4#include <errno.h>
5#include <linux/types.h>
6#include <linux/bpf.h>
7#include <bpf/bpf_helpers.h>
8#include <bpf/bpf_tracing.h>
9
10#define OP_BATCH 64
11
12struct update_ctx {
13	unsigned int from;
14	unsigned int step;
15};
16
17struct {
18	__uint(type, BPF_MAP_TYPE_HASH);
19	__uint(key_size, 4);
20	__uint(map_flags, BPF_F_NO_PREALLOC);
21} htab SEC(".maps");
22
23char _license[] SEC("license") = "GPL";
24
25unsigned char zeroed_value[4096];
26unsigned int nr_thread = 0;
27long op_cnt = 0;
28
29static int write_htab(unsigned int i, struct update_ctx *ctx, unsigned int flags)
30{
31	bpf_map_update_elem(&htab, &ctx->from, zeroed_value, flags);
32	ctx->from += ctx->step;
33
34	return 0;
35}
36
37static int overwrite_htab(unsigned int i, struct update_ctx *ctx)
38{
39	return write_htab(i, ctx, 0);
40}
41
42static int newwrite_htab(unsigned int i, struct update_ctx *ctx)
43{
44	return write_htab(i, ctx, BPF_NOEXIST);
45}
46
47static int del_htab(unsigned int i, struct update_ctx *ctx)
48{
49	bpf_map_delete_elem(&htab, &ctx->from);
50	ctx->from += ctx->step;
51
52	return 0;
53}
54
55SEC("?tp/syscalls/sys_enter_getpgid")
56int overwrite(void *ctx)
57{
58	struct update_ctx update;
59
60	update.from = bpf_get_smp_processor_id();
61	update.step = nr_thread;
62	bpf_loop(OP_BATCH, overwrite_htab, &update, 0);
63	__sync_fetch_and_add(&op_cnt, 1);
64	return 0;
65}
66
67SEC("?tp/syscalls/sys_enter_getpgid")
68int batch_add_batch_del(void *ctx)
69{
70	struct update_ctx update;
71
72	update.from = bpf_get_smp_processor_id();
73	update.step = nr_thread;
74	bpf_loop(OP_BATCH, overwrite_htab, &update, 0);
75
76	update.from = bpf_get_smp_processor_id();
77	bpf_loop(OP_BATCH, del_htab, &update, 0);
78
79	__sync_fetch_and_add(&op_cnt, 2);
80	return 0;
81}
82
83SEC("?tp/syscalls/sys_enter_getpgid")
84int add_only(void *ctx)
85{
86	struct update_ctx update;
87
88	update.from = bpf_get_smp_processor_id() / 2;
89	update.step = nr_thread / 2;
90	bpf_loop(OP_BATCH, newwrite_htab, &update, 0);
91	__sync_fetch_and_add(&op_cnt, 1);
92	return 0;
93}
94
95SEC("?tp/syscalls/sys_enter_getppid")
96int del_only(void *ctx)
97{
98	struct update_ctx update;
99
100	update.from = bpf_get_smp_processor_id() / 2;
101	update.step = nr_thread / 2;
102	bpf_loop(OP_BATCH, del_htab, &update, 0);
103	__sync_fetch_and_add(&op_cnt, 1);
104	return 0;
105}
106