This source file includes following definitions.
- get_thread_state
- get_frame_data
- __on_event
- SEC
1
2
3 #include <linux/sched.h>
4 #include <linux/ptrace.h>
5 #include <stdint.h>
6 #include <stddef.h>
7 #include <stdbool.h>
8 #include <linux/bpf.h>
9 #include "bpf_helpers.h"
10
11 #define FUNCTION_NAME_LEN 64
12 #define FILE_NAME_LEN 128
13 #define TASK_COMM_LEN 16
14
15 typedef struct {
16 int PyThreadState_frame;
17 int PyThreadState_thread;
18 int PyFrameObject_back;
19 int PyFrameObject_code;
20 int PyFrameObject_lineno;
21 int PyCodeObject_filename;
22 int PyCodeObject_name;
23 int String_data;
24 int String_size;
25 } OffsetConfig;
26
27 typedef struct {
28 uintptr_t current_state_addr;
29 uintptr_t tls_key_addr;
30 OffsetConfig offsets;
31 bool use_tls;
32 } PidData;
33
34 typedef struct {
35 uint32_t success;
36 } Stats;
37
38 typedef struct {
39 char name[FUNCTION_NAME_LEN];
40 char file[FILE_NAME_LEN];
41 } Symbol;
42
43 typedef struct {
44 uint32_t pid;
45 uint32_t tid;
46 char comm[TASK_COMM_LEN];
47 int32_t kernel_stack_id;
48 int32_t user_stack_id;
49 bool thread_current;
50 bool pthread_match;
51 bool stack_complete;
52 int16_t stack_len;
53 int32_t stack[STACK_MAX_LEN];
54
55 int has_meta;
56 int metadata;
57 char dummy_safeguard;
58 } Event;
59
60
61 typedef int pid_t;
62
63 typedef struct {
64 void* f_back;
65 void* f_code;
66 void* co_filename;
67 void* co_name;
68 } FrameData;
69
70 static __always_inline void *get_thread_state(void *tls_base, PidData *pidData)
71 {
72 void* thread_state;
73 int key;
74
75 bpf_probe_read(&key, sizeof(key), (void*)(long)pidData->tls_key_addr);
76 bpf_probe_read(&thread_state, sizeof(thread_state),
77 tls_base + 0x310 + key * 0x10 + 0x08);
78 return thread_state;
79 }
80
81 static __always_inline bool get_frame_data(void *frame_ptr, PidData *pidData,
82 FrameData *frame, Symbol *symbol)
83 {
84
85 bpf_probe_read(&frame->f_back,
86 sizeof(frame->f_back),
87 frame_ptr + pidData->offsets.PyFrameObject_back);
88 bpf_probe_read(&frame->f_code,
89 sizeof(frame->f_code),
90 frame_ptr + pidData->offsets.PyFrameObject_code);
91
92
93 if (!frame->f_code)
94 return false;
95 bpf_probe_read(&frame->co_filename,
96 sizeof(frame->co_filename),
97 frame->f_code + pidData->offsets.PyCodeObject_filename);
98 bpf_probe_read(&frame->co_name,
99 sizeof(frame->co_name),
100 frame->f_code + pidData->offsets.PyCodeObject_name);
101
102 if (frame->co_filename)
103 bpf_probe_read_str(&symbol->file,
104 sizeof(symbol->file),
105 frame->co_filename + pidData->offsets.String_data);
106 if (frame->co_name)
107 bpf_probe_read_str(&symbol->name,
108 sizeof(symbol->name),
109 frame->co_name + pidData->offsets.String_data);
110 return true;
111 }
112
113 struct {
114 __uint(type, BPF_MAP_TYPE_HASH);
115 __uint(max_entries, 1);
116 __type(key, int);
117 __type(value, PidData);
118 } pidmap SEC(".maps");
119
120 struct {
121 __uint(type, BPF_MAP_TYPE_HASH);
122 __uint(max_entries, 1);
123 __type(key, int);
124 __type(value, Event);
125 } eventmap SEC(".maps");
126
127 struct {
128 __uint(type, BPF_MAP_TYPE_HASH);
129 __uint(max_entries, 1);
130 __type(key, Symbol);
131 __type(value, int);
132 } symbolmap SEC(".maps");
133
134 struct {
135 __uint(type, BPF_MAP_TYPE_ARRAY);
136 __uint(max_entries, 1);
137 __type(key, int);
138 __type(value, Stats);
139 } statsmap SEC(".maps");
140
141 struct {
142 __uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY);
143 __uint(max_entries, 32);
144 __uint(key_size, sizeof(int));
145 __uint(value_size, sizeof(int));
146 } perfmap SEC(".maps");
147
148 struct {
149 __uint(type, BPF_MAP_TYPE_STACK_TRACE);
150 __uint(max_entries, 1000);
151 __uint(key_size, sizeof(int));
152 __uint(value_size, sizeof(long long) * 127);
153 } stackmap SEC(".maps");
154
155 static __always_inline int __on_event(struct pt_regs *ctx)
156 {
157 uint64_t pid_tgid = bpf_get_current_pid_tgid();
158 pid_t pid = (pid_t)(pid_tgid >> 32);
159 PidData* pidData = bpf_map_lookup_elem(&pidmap, &pid);
160 if (!pidData)
161 return 0;
162
163 int zero = 0;
164 Event* event = bpf_map_lookup_elem(&eventmap, &zero);
165 if (!event)
166 return 0;
167
168 event->pid = pid;
169
170 event->tid = (pid_t)pid_tgid;
171 bpf_get_current_comm(&event->comm, sizeof(event->comm));
172
173 event->user_stack_id = bpf_get_stackid(ctx, &stackmap, BPF_F_USER_STACK);
174 event->kernel_stack_id = bpf_get_stackid(ctx, &stackmap, 0);
175
176 void* thread_state_current = (void*)0;
177 bpf_probe_read(&thread_state_current,
178 sizeof(thread_state_current),
179 (void*)(long)pidData->current_state_addr);
180
181 struct task_struct* task = (struct task_struct*)bpf_get_current_task();
182 void* tls_base = (void*)task;
183
184 void* thread_state = pidData->use_tls ? get_thread_state(tls_base, pidData)
185 : thread_state_current;
186 event->thread_current = thread_state == thread_state_current;
187
188 if (pidData->use_tls) {
189 uint64_t pthread_created;
190 uint64_t pthread_self;
191 bpf_probe_read(&pthread_self, sizeof(pthread_self), tls_base + 0x10);
192
193 bpf_probe_read(&pthread_created,
194 sizeof(pthread_created),
195 thread_state + pidData->offsets.PyThreadState_thread);
196 event->pthread_match = pthread_created == pthread_self;
197 } else {
198 event->pthread_match = 1;
199 }
200
201 if (event->pthread_match || !pidData->use_tls) {
202 void* frame_ptr;
203 FrameData frame;
204 Symbol sym = {};
205 int cur_cpu = bpf_get_smp_processor_id();
206
207 bpf_probe_read(&frame_ptr,
208 sizeof(frame_ptr),
209 thread_state + pidData->offsets.PyThreadState_frame);
210
211 int32_t* symbol_counter = bpf_map_lookup_elem(&symbolmap, &sym);
212 if (symbol_counter == NULL)
213 return 0;
214 #ifdef NO_UNROLL
215 #pragma clang loop unroll(disable)
216 #else
217 #pragma clang loop unroll(full)
218 #endif
219
220 for (int i = 0; i < STACK_MAX_LEN; ++i) {
221 if (frame_ptr && get_frame_data(frame_ptr, pidData, &frame, &sym)) {
222 int32_t new_symbol_id = *symbol_counter * 64 + cur_cpu;
223 int32_t *symbol_id = bpf_map_lookup_elem(&symbolmap, &sym);
224 if (!symbol_id) {
225 bpf_map_update_elem(&symbolmap, &sym, &zero, 0);
226 symbol_id = bpf_map_lookup_elem(&symbolmap, &sym);
227 if (!symbol_id)
228 return 0;
229 }
230 if (*symbol_id == new_symbol_id)
231 (*symbol_counter)++;
232 event->stack[i] = *symbol_id;
233 event->stack_len = i + 1;
234 frame_ptr = frame.f_back;
235 }
236 }
237 event->stack_complete = frame_ptr == NULL;
238 } else {
239 event->stack_complete = 1;
240 }
241
242 Stats* stats = bpf_map_lookup_elem(&statsmap, &zero);
243 if (stats)
244 stats->success++;
245
246 event->has_meta = 0;
247 bpf_perf_event_output(ctx, &perfmap, 0, event, offsetof(Event, metadata));
248 return 0;
249 }
250
251 SEC("raw_tracepoint/kfree_skb")
252 int on_event(struct pt_regs* ctx)
253 {
254 int i, ret = 0;
255 ret |= __on_event(ctx);
256 ret |= __on_event(ctx);
257 ret |= __on_event(ctx);
258 ret |= __on_event(ctx);
259 ret |= __on_event(ctx);
260 return ret;
261 }
262
263 char _license[] SEC("license") = "GPL";