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67337c4a MD |
1 | // SPDX-License-Identifier: MIT |
2 | /* | |
3 | * Copyright 2022 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
4 | */ | |
5 | ||
6 | #ifndef _SIDE_TRACE_H | |
7 | #define _SIDE_TRACE_H | |
8 | ||
9 | #include <stdint.h> | |
10 | #include <inttypes.h> | |
11 | #include <stdlib.h> | |
12 | #include <stdio.h> | |
13 | #include <math.h> | |
25ea4c79 | 14 | #include <stdbool.h> |
441235e7 | 15 | #include <stddef.h> |
67337c4a MD |
16 | #include <side/macros.h> |
17 | #include <side/endian.h> | |
18 | ||
19 | /* | |
551d8244 | 20 | * SIDE stands for "Software Instrumentation Dynamically Enabled" |
67337c4a | 21 | * |
2e197497 | 22 | * This is an instrumentation ABI for Linux user-space, which exposes an |
67337c4a MD |
23 | * instrumentation type system and facilities allowing a kernel or |
24 | * user-space tracer to consume user-space instrumentation. | |
25 | * | |
35e4f870 MD |
26 | * The extensibility scheme for the SIDE ABI for event state is as |
27 | * follows: | |
67337c4a | 28 | * |
b2a84b9f MD |
29 | * * If the semantic of the "struct side_event_state_N" fields change, |
30 | * the SIDE_EVENT_STATE_ABI_VERSION should be increased. The | |
31 | * "struct side_event_state_N" is not extensible and must have its | |
32 | * ABI version increased whenever it is changed. Note that increasing | |
33 | * the version of SIDE_EVENT_DESCRIPTION_ABI_VERSION is not necessary | |
34 | * when changing the layout of "struct side_event_state_N". | |
67337c4a MD |
35 | */ |
36 | ||
b2a84b9f | 37 | #define SIDE_EVENT_STATE_ABI_VERSION 0 |
67337c4a | 38 | |
b8dfb348 MD |
39 | #include <side/abi/event-description.h> |
40 | #include <side/abi/type-argument.h> | |
57553dfd | 41 | #include <side/instrumentation-c-api.h> |
67337c4a MD |
42 | |
43 | enum side_error { | |
44 | SIDE_ERROR_OK = 0, | |
45 | SIDE_ERROR_INVAL = 1, | |
46 | SIDE_ERROR_EXIST = 2, | |
47 | SIDE_ERROR_NOMEM = 3, | |
48 | SIDE_ERROR_NOENT = 4, | |
49 | SIDE_ERROR_EXITING = 5, | |
50 | }; | |
51 | ||
0d747f98 MD |
52 | /* |
53 | * This structure is _not_ packed to allow atomic operations on its | |
b2a84b9f MD |
54 | * fields. Changes to this structure must bump the "Event state ABI |
55 | * version" and tracers _must_ learn how to deal with this ABI, | |
56 | * otherwise they should reject the event. | |
0d747f98 | 57 | */ |
b2a84b9f | 58 | |
0d747f98 | 59 | struct side_event_state { |
b2a84b9f MD |
60 | uint32_t version; /* Event state ABI version. */ |
61 | }; | |
62 | ||
63 | struct side_event_state_0 { | |
49aea3ef | 64 | struct side_event_state parent; /* Required first field. */ |
3cac1780 | 65 | uint32_t nr_callbacks; |
692ffa8b | 66 | uintptr_t enabled; |
7269a8a3 MD |
67 | const struct side_callback *callbacks; |
68 | struct side_event_description *desc; | |
0d747f98 MD |
69 | }; |
70 | ||
67337c4a MD |
71 | #ifdef __cplusplus |
72 | extern "C" { | |
73 | #endif | |
74 | ||
867b4725 | 75 | struct side_callback; |
f0b01832 MD |
76 | struct side_tracer_handle; |
77 | struct side_statedump_request_handle; | |
2e197497 | 78 | |
867b4725 | 79 | extern const char side_empty_callback[]; |
67337c4a | 80 | |
0d747f98 | 81 | void side_call(const struct side_event_state *state, |
67337c4a | 82 | const struct side_arg_vec *side_arg_vec); |
0d747f98 | 83 | void side_call_variadic(const struct side_event_state *state, |
67337c4a MD |
84 | const struct side_arg_vec *side_arg_vec, |
85 | const struct side_arg_dynamic_struct *var_struct); | |
86 | ||
87 | struct side_events_register_handle *side_events_register(struct side_event_description **events, | |
88 | uint32_t nr_events); | |
89 | void side_events_unregister(struct side_events_register_handle *handle); | |
90 | ||
91 | /* | |
92 | * Userspace tracer registration API. This allows userspace tracers to | |
93 | * register event notification callbacks to be notified of the currently | |
94 | * registered instrumentation, and to register their callbacks to | |
95 | * specific events. | |
96 | */ | |
97 | typedef void (*side_tracer_callback_func)(const struct side_event_description *desc, | |
98 | const struct side_arg_vec *side_arg_vec, | |
99 | void *priv); | |
100 | typedef void (*side_tracer_callback_variadic_func)(const struct side_event_description *desc, | |
101 | const struct side_arg_vec *side_arg_vec, | |
102 | const struct side_arg_dynamic_struct *var_struct, | |
103 | void *priv); | |
104 | ||
105 | int side_tracer_callback_register(struct side_event_description *desc, | |
106 | side_tracer_callback_func call, | |
92c377f9 | 107 | void *priv, void *key); |
67337c4a MD |
108 | int side_tracer_callback_variadic_register(struct side_event_description *desc, |
109 | side_tracer_callback_variadic_func call_variadic, | |
92c377f9 | 110 | void *priv, void *key); |
67337c4a MD |
111 | int side_tracer_callback_unregister(struct side_event_description *desc, |
112 | side_tracer_callback_func call, | |
92c377f9 | 113 | void *priv, void *key); |
67337c4a MD |
114 | int side_tracer_callback_variadic_unregister(struct side_event_description *desc, |
115 | side_tracer_callback_variadic_func call_variadic, | |
92c377f9 | 116 | void *priv, void *key); |
67337c4a MD |
117 | |
118 | enum side_tracer_notification { | |
119 | SIDE_TRACER_NOTIFICATION_INSERT_EVENTS, | |
120 | SIDE_TRACER_NOTIFICATION_REMOVE_EVENTS, | |
121 | }; | |
122 | ||
123 | /* Callback is invoked with side library internal lock held. */ | |
124 | struct side_tracer_handle *side_tracer_event_notification_register( | |
125 | void (*cb)(enum side_tracer_notification notif, | |
126 | struct side_event_description **events, uint32_t nr_events, void *priv), | |
127 | void *priv); | |
128 | void side_tracer_event_notification_unregister(struct side_tracer_handle *handle); | |
129 | ||
f0b01832 MD |
130 | /* |
131 | * The side_statedump_call APIs should be used for application/library | |
132 | * state dump. | |
133 | * The statedump callback dumps application state to tracers by invoking | |
134 | * side_statedump_call APIs. | |
135 | * The statedump callback is invoked with side library internal lock held. | |
136 | * The statedump callback should not invoke functions which require the | |
137 | * side library internal lock. | |
138 | */ | |
139 | void side_statedump_call(const struct side_event_state *state, | |
140 | const struct side_arg_vec *side_arg_vec); | |
141 | void side_statedump_call_variadic(const struct side_event_state *state, | |
142 | const struct side_arg_vec *side_arg_vec, | |
143 | const struct side_arg_dynamic_struct *var_struct); | |
144 | ||
145 | /* | |
146 | * If side_statedump_request_notification_register is invoked from | |
147 | * library constructors and side_statedump_request_notification_unregister | |
148 | * from library destructors, make sure to: | |
149 | * - invoke side_event_description_ptr_init before registration of the | |
150 | * callback, | |
151 | * - invoke side_event_description_ptr_exit after unregistration of the | |
152 | * callback. | |
153 | */ | |
154 | ||
155 | struct side_statedump_request_handle *side_statedump_request_notification_register(void (*statedump_cb)(void)); | |
156 | void side_statedump_request_notification_unregister(struct side_statedump_request_handle *handle); | |
157 | ||
158 | void side_tracer_statedump_request(void *key); | |
159 | ||
67337c4a MD |
160 | /* |
161 | * Explicit hooks to initialize/finalize the side instrumentation | |
162 | * library. Those are also library constructor/destructor. | |
163 | */ | |
164 | void side_init(void) __attribute__((constructor)); | |
165 | void side_exit(void) __attribute__((destructor)); | |
166 | ||
167 | /* | |
168 | * The following constructors/destructors perform automatic registration | |
169 | * of the declared side events. Those may have to be called explicitly | |
170 | * in a statically linked library. | |
171 | */ | |
172 | ||
173 | /* | |
174 | * These weak symbols, the constructor, and destructor take care of | |
175 | * registering only _one_ instance of the side instrumentation per | |
176 | * shared-ojbect (or for the whole main program). | |
177 | */ | |
178 | extern struct side_event_description * __start_side_event_description_ptr[] | |
179 | __attribute__((weak, visibility("hidden"))); | |
180 | extern struct side_event_description * __stop_side_event_description_ptr[] | |
181 | __attribute__((weak, visibility("hidden"))); | |
182 | int side_event_description_ptr_registered | |
183 | __attribute__((weak, visibility("hidden"))); | |
184 | struct side_events_register_handle *side_events_handle | |
185 | __attribute__((weak, visibility("hidden"))); | |
186 | ||
187 | static void | |
188 | side_event_description_ptr_init(void) | |
189 | __attribute__((no_instrument_function)) | |
190 | __attribute__((constructor)); | |
191 | static void | |
192 | side_event_description_ptr_init(void) | |
193 | { | |
194 | if (side_event_description_ptr_registered++) | |
195 | return; | |
196 | side_events_handle = side_events_register(__start_side_event_description_ptr, | |
197 | __stop_side_event_description_ptr - __start_side_event_description_ptr); | |
198 | } | |
199 | ||
200 | static void | |
201 | side_event_description_ptr_exit(void) | |
202 | __attribute__((no_instrument_function)) | |
203 | __attribute__((destructor)); | |
204 | static void | |
205 | side_event_description_ptr_exit(void) | |
206 | { | |
207 | if (--side_event_description_ptr_registered) | |
208 | return; | |
209 | side_events_unregister(side_events_handle); | |
210 | side_events_handle = NULL; | |
211 | } | |
212 | ||
213 | #ifdef __cplusplus | |
214 | } | |
215 | #endif | |
216 | ||
217 | #endif /* _SIDE_TRACE_H */ |