1 #include <linux/ptrace.h>
2 #include <linux/version.h>
3 #include <uapi/linux/bpf.h>
4 #include <bpf/bpf_helpers.h>
5 #include <bpf/bpf_tracing.h>
6 #include <bpf/bpf_core_read.h>
7
8 struct {
9 __uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY);
10 __uint(key_size, sizeof(int));
11 __uint(value_size, sizeof(u32));
12 __uint(max_entries, 64);
13 } counters SEC(".maps");
14
15 struct {
16 __uint(type, BPF_MAP_TYPE_HASH);
17 __type(key, int);
18 __type(value, u64);
19 __uint(max_entries, 64);
20 } values SEC(".maps");
21
22 struct {
23 __uint(type, BPF_MAP_TYPE_HASH);
24 __type(key, int);
25 __type(value, struct bpf_perf_event_value);
26 __uint(max_entries, 64);
27 } values2 SEC(".maps");
28
29 SEC("kprobe/htab_map_get_next_key")
bpf_prog1(struct pt_regs * ctx)30 int bpf_prog1(struct pt_regs *ctx)
31 {
32 u32 key = bpf_get_smp_processor_id();
33 u64 count, *val;
34 s64 error;
35
36 count = bpf_perf_event_read(&counters, key);
37 error = (s64)count;
38 if (error <= -2 && error >= -22)
39 return 0;
40
41 val = bpf_map_lookup_elem(&values, &key);
42 if (val)
43 *val = count;
44 else
45 bpf_map_update_elem(&values, &key, &count, BPF_NOEXIST);
46
47 return 0;
48 }
49
50 /*
51 * Since *_map_lookup_elem can't be expected to trigger bpf programs
52 * due to potential deadlocks (bpf_disable_instrumentation), this bpf
53 * program will be attached to bpf_map_copy_value (which is called
54 * from map_lookup_elem) and will only filter the hashtable type.
55 */
56 SEC("kprobe/bpf_map_copy_value")
BPF_KPROBE(bpf_prog2,struct bpf_map * map)57 int BPF_KPROBE(bpf_prog2, struct bpf_map *map)
58 {
59 u32 key = bpf_get_smp_processor_id();
60 struct bpf_perf_event_value *val, buf;
61 enum bpf_map_type type;
62 int error;
63
64 type = BPF_CORE_READ(map, map_type);
65 if (type != BPF_MAP_TYPE_HASH)
66 return 0;
67
68 error = bpf_perf_event_read_value(&counters, key, &buf, sizeof(buf));
69 if (error)
70 return 0;
71
72 val = bpf_map_lookup_elem(&values2, &key);
73 if (val)
74 *val = buf;
75 else
76 bpf_map_update_elem(&values2, &key, &buf, BPF_NOEXIST);
77
78 return 0;
79 }
80
81 char _license[] SEC("license") = "GPL";
82 u32 _version SEC("version") = LINUX_VERSION_CODE;
83