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 
12 struct update_ctx {
13 	unsigned int from;
14 	unsigned int step;
15 };
16 
17 struct {
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 
23 char _license[] SEC("license") = "GPL";
24 
25 unsigned char zeroed_value[4096];
26 unsigned int nr_thread = 0;
27 long op_cnt = 0;
28 
29 static 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 
37 static int overwrite_htab(unsigned int i, struct update_ctx *ctx)
38 {
39 	return write_htab(i, ctx, 0);
40 }
41 
42 static int newwrite_htab(unsigned int i, struct update_ctx *ctx)
43 {
44 	return write_htab(i, ctx, BPF_NOEXIST);
45 }
46 
47 static 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 
55 SEC("?tp/syscalls/sys_enter_getpgid")
56 int 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 
67 SEC("?tp/syscalls/sys_enter_getpgid")
68 int 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 
83 SEC("?tp/syscalls/sys_enter_getpgid")
84 int 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 
95 SEC("?tp/syscalls/sys_enter_getppid")
96 int 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