Commit | Line | Data |
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69d262a9 WN |
1 | /* |
2 | * bpf-loader.c | |
3 | * | |
4 | * Copyright (C) 2015 Wang Nan <wangnan0@huawei.com> | |
5 | * Copyright (C) 2015 Huawei Inc. | |
6 | */ | |
7 | ||
8 | #include <bpf/libbpf.h> | |
9 | #include <linux/err.h> | |
10 | #include "perf.h" | |
11 | #include "debug.h" | |
12 | #include "bpf-loader.h" | |
aa3abf30 WN |
13 | #include "probe-event.h" |
14 | #include "probe-finder.h" // for MAX_PROBES | |
d509db04 | 15 | #include "llvm-utils.h" |
69d262a9 WN |
16 | |
17 | #define DEFINE_PRINT_FN(name, level) \ | |
18 | static int libbpf_##name(const char *fmt, ...) \ | |
19 | { \ | |
20 | va_list args; \ | |
21 | int ret; \ | |
22 | \ | |
23 | va_start(args, fmt); \ | |
24 | ret = veprintf(level, verbose, pr_fmt(fmt), args);\ | |
25 | va_end(args); \ | |
26 | return ret; \ | |
27 | } | |
28 | ||
29 | DEFINE_PRINT_FN(warning, 0) | |
30 | DEFINE_PRINT_FN(info, 0) | |
31 | DEFINE_PRINT_FN(debug, 1) | |
32 | ||
aa3abf30 WN |
33 | struct bpf_prog_priv { |
34 | struct perf_probe_event pev; | |
35 | }; | |
36 | ||
d509db04 | 37 | struct bpf_object *bpf__prepare_load(const char *filename, bool source) |
69d262a9 WN |
38 | { |
39 | struct bpf_object *obj; | |
40 | static bool libbpf_initialized; | |
41 | ||
42 | if (!libbpf_initialized) { | |
43 | libbpf_set_print(libbpf_warning, | |
44 | libbpf_info, | |
45 | libbpf_debug); | |
46 | libbpf_initialized = true; | |
47 | } | |
48 | ||
d509db04 WN |
49 | if (source) { |
50 | int err; | |
51 | void *obj_buf; | |
52 | size_t obj_buf_sz; | |
53 | ||
54 | err = llvm__compile_bpf(filename, &obj_buf, &obj_buf_sz); | |
55 | if (err) | |
56 | return ERR_PTR(err); | |
57 | obj = bpf_object__open_buffer(obj_buf, obj_buf_sz, filename); | |
58 | free(obj_buf); | |
59 | } else | |
60 | obj = bpf_object__open(filename); | |
61 | ||
69d262a9 WN |
62 | if (!obj) { |
63 | pr_debug("bpf: failed to load %s\n", filename); | |
64 | return ERR_PTR(-EINVAL); | |
65 | } | |
66 | ||
67 | return obj; | |
68 | } | |
69 | ||
70 | void bpf__clear(void) | |
71 | { | |
72 | struct bpf_object *obj, *tmp; | |
73 | ||
aa3abf30 WN |
74 | bpf_object__for_each_safe(obj, tmp) { |
75 | bpf__unprobe(obj); | |
69d262a9 | 76 | bpf_object__close(obj); |
aa3abf30 WN |
77 | } |
78 | } | |
79 | ||
80 | static void | |
81 | bpf_prog_priv__clear(struct bpf_program *prog __maybe_unused, | |
82 | void *_priv) | |
83 | { | |
84 | struct bpf_prog_priv *priv = _priv; | |
85 | ||
86 | cleanup_perf_probe_events(&priv->pev, 1); | |
87 | free(priv); | |
88 | } | |
89 | ||
90 | static int | |
91 | config_bpf_program(struct bpf_program *prog) | |
92 | { | |
93 | struct perf_probe_event *pev = NULL; | |
94 | struct bpf_prog_priv *priv = NULL; | |
95 | const char *config_str; | |
96 | int err; | |
97 | ||
98 | config_str = bpf_program__title(prog, false); | |
99 | if (!config_str) { | |
100 | pr_debug("bpf: unable to get title for program\n"); | |
101 | return -EINVAL; | |
102 | } | |
103 | ||
104 | priv = calloc(sizeof(*priv), 1); | |
105 | if (!priv) { | |
106 | pr_debug("bpf: failed to alloc priv\n"); | |
107 | return -ENOMEM; | |
108 | } | |
109 | pev = &priv->pev; | |
110 | ||
111 | pr_debug("bpf: config program '%s'\n", config_str); | |
112 | err = parse_perf_probe_command(config_str, pev); | |
113 | if (err < 0) { | |
114 | pr_debug("bpf: '%s' is not a valid config string\n", | |
115 | config_str); | |
116 | err = -EINVAL; | |
117 | goto errout; | |
118 | } | |
119 | ||
120 | if (pev->group && strcmp(pev->group, PERF_BPF_PROBE_GROUP)) { | |
121 | pr_debug("bpf: '%s': group for event is set and not '%s'.\n", | |
122 | config_str, PERF_BPF_PROBE_GROUP); | |
123 | err = -EINVAL; | |
124 | goto errout; | |
125 | } else if (!pev->group) | |
126 | pev->group = strdup(PERF_BPF_PROBE_GROUP); | |
127 | ||
128 | if (!pev->group) { | |
129 | pr_debug("bpf: strdup failed\n"); | |
130 | err = -ENOMEM; | |
131 | goto errout; | |
132 | } | |
133 | ||
134 | if (!pev->event) { | |
135 | pr_debug("bpf: '%s': event name is missing\n", | |
136 | config_str); | |
137 | err = -EINVAL; | |
138 | goto errout; | |
139 | } | |
140 | pr_debug("bpf: config '%s' is ok\n", config_str); | |
141 | ||
142 | err = bpf_program__set_private(prog, priv, bpf_prog_priv__clear); | |
143 | if (err) { | |
144 | pr_debug("Failed to set priv for program '%s'\n", config_str); | |
145 | goto errout; | |
146 | } | |
147 | ||
148 | return 0; | |
149 | ||
150 | errout: | |
151 | if (pev) | |
152 | clear_perf_probe_event(pev); | |
153 | free(priv); | |
154 | return err; | |
155 | } | |
156 | ||
157 | static int bpf__prepare_probe(void) | |
158 | { | |
159 | static int err = 0; | |
160 | static bool initialized = false; | |
161 | ||
162 | /* | |
163 | * Make err static, so if init failed the first, bpf__prepare_probe() | |
164 | * fails each time without calling init_probe_symbol_maps multiple | |
165 | * times. | |
166 | */ | |
167 | if (initialized) | |
168 | return err; | |
169 | ||
170 | initialized = true; | |
171 | err = init_probe_symbol_maps(false); | |
172 | if (err < 0) | |
173 | pr_debug("Failed to init_probe_symbol_maps\n"); | |
174 | probe_conf.max_probes = MAX_PROBES; | |
175 | return err; | |
176 | } | |
177 | ||
178 | int bpf__probe(struct bpf_object *obj) | |
179 | { | |
180 | int err = 0; | |
181 | struct bpf_program *prog; | |
182 | struct bpf_prog_priv *priv; | |
183 | struct perf_probe_event *pev; | |
184 | ||
185 | err = bpf__prepare_probe(); | |
186 | if (err) { | |
187 | pr_debug("bpf__prepare_probe failed\n"); | |
188 | return err; | |
189 | } | |
190 | ||
191 | bpf_object__for_each_program(prog, obj) { | |
192 | err = config_bpf_program(prog); | |
193 | if (err) | |
194 | goto out; | |
195 | ||
196 | err = bpf_program__get_private(prog, (void **)&priv); | |
197 | if (err || !priv) | |
198 | goto out; | |
199 | pev = &priv->pev; | |
200 | ||
201 | err = convert_perf_probe_events(pev, 1); | |
202 | if (err < 0) { | |
203 | pr_debug("bpf_probe: failed to convert perf probe events"); | |
204 | goto out; | |
205 | } | |
206 | ||
207 | err = apply_perf_probe_events(pev, 1); | |
208 | if (err < 0) { | |
209 | pr_debug("bpf_probe: failed to apply perf probe events"); | |
210 | goto out; | |
211 | } | |
212 | } | |
213 | out: | |
214 | return err < 0 ? err : 0; | |
215 | } | |
216 | ||
217 | #define EVENTS_WRITE_BUFSIZE 4096 | |
218 | int bpf__unprobe(struct bpf_object *obj) | |
219 | { | |
220 | int err, ret = 0; | |
221 | struct bpf_program *prog; | |
222 | struct bpf_prog_priv *priv; | |
223 | ||
224 | bpf_object__for_each_program(prog, obj) { | |
225 | int i; | |
226 | ||
227 | err = bpf_program__get_private(prog, (void **)&priv); | |
228 | if (err || !priv) | |
229 | continue; | |
230 | ||
231 | for (i = 0; i < priv->pev.ntevs; i++) { | |
232 | struct probe_trace_event *tev = &priv->pev.tevs[i]; | |
233 | char name_buf[EVENTS_WRITE_BUFSIZE]; | |
234 | struct strfilter *delfilter; | |
235 | ||
236 | snprintf(name_buf, EVENTS_WRITE_BUFSIZE, | |
237 | "%s:%s", tev->group, tev->event); | |
238 | name_buf[EVENTS_WRITE_BUFSIZE - 1] = '\0'; | |
239 | ||
240 | delfilter = strfilter__new(name_buf, NULL); | |
241 | if (!delfilter) { | |
242 | pr_debug("Failed to create filter for unprobing\n"); | |
243 | ret = -ENOMEM; | |
244 | continue; | |
245 | } | |
246 | ||
247 | err = del_perf_probe_events(delfilter); | |
248 | strfilter__delete(delfilter); | |
249 | if (err) { | |
250 | pr_debug("Failed to delete %s\n", name_buf); | |
251 | ret = err; | |
252 | continue; | |
253 | } | |
254 | } | |
255 | } | |
256 | return ret; | |
257 | } | |
258 | ||
1e5e3ee8 WN |
259 | int bpf__load(struct bpf_object *obj) |
260 | { | |
261 | int err; | |
262 | ||
263 | err = bpf_object__load(obj); | |
264 | if (err) { | |
265 | pr_debug("bpf: load objects failed\n"); | |
266 | return err; | |
267 | } | |
268 | return 0; | |
269 | } | |
270 | ||
4edf30e3 WN |
271 | int bpf__foreach_tev(struct bpf_object *obj, |
272 | bpf_prog_iter_callback_t func, | |
273 | void *arg) | |
274 | { | |
275 | struct bpf_program *prog; | |
276 | int err; | |
277 | ||
278 | bpf_object__for_each_program(prog, obj) { | |
279 | struct probe_trace_event *tev; | |
280 | struct perf_probe_event *pev; | |
281 | struct bpf_prog_priv *priv; | |
282 | int i, fd; | |
283 | ||
284 | err = bpf_program__get_private(prog, | |
285 | (void **)&priv); | |
286 | if (err || !priv) { | |
287 | pr_debug("bpf: failed to get private field\n"); | |
288 | return -EINVAL; | |
289 | } | |
290 | ||
291 | pev = &priv->pev; | |
292 | for (i = 0; i < pev->ntevs; i++) { | |
293 | tev = &pev->tevs[i]; | |
294 | ||
295 | fd = bpf_program__fd(prog); | |
296 | if (fd < 0) { | |
297 | pr_debug("bpf: failed to get file descriptor\n"); | |
298 | return fd; | |
299 | } | |
300 | ||
301 | err = (*func)(tev, fd, arg); | |
302 | if (err) { | |
303 | pr_debug("bpf: call back failed, stop iterate\n"); | |
304 | return err; | |
305 | } | |
306 | } | |
307 | } | |
308 | return 0; | |
309 | } | |
310 | ||
aa3abf30 WN |
311 | #define bpf__strerror_head(err, buf, size) \ |
312 | char sbuf[STRERR_BUFSIZE], *emsg;\ | |
313 | if (!size)\ | |
314 | return 0;\ | |
315 | if (err < 0)\ | |
316 | err = -err;\ | |
317 | emsg = strerror_r(err, sbuf, sizeof(sbuf));\ | |
318 | switch (err) {\ | |
319 | default:\ | |
320 | scnprintf(buf, size, "%s", emsg);\ | |
321 | break; | |
322 | ||
323 | #define bpf__strerror_entry(val, fmt...)\ | |
324 | case val: {\ | |
325 | scnprintf(buf, size, fmt);\ | |
326 | break;\ | |
327 | } | |
328 | ||
329 | #define bpf__strerror_end(buf, size)\ | |
330 | }\ | |
331 | buf[size - 1] = '\0'; | |
332 | ||
333 | int bpf__strerror_probe(struct bpf_object *obj __maybe_unused, | |
334 | int err, char *buf, size_t size) | |
335 | { | |
336 | bpf__strerror_head(err, buf, size); | |
337 | bpf__strerror_entry(EEXIST, "Probe point exist. Try use 'perf probe -d \"*\"'"); | |
338 | bpf__strerror_entry(EPERM, "You need to be root, and /proc/sys/kernel/kptr_restrict should be 0\n"); | |
339 | bpf__strerror_entry(ENOENT, "You need to check probing points in BPF file\n"); | |
340 | bpf__strerror_end(buf, size); | |
341 | return 0; | |
69d262a9 | 342 | } |
1e5e3ee8 WN |
343 | |
344 | int bpf__strerror_load(struct bpf_object *obj __maybe_unused, | |
345 | int err, char *buf, size_t size) | |
346 | { | |
347 | bpf__strerror_head(err, buf, size); | |
348 | bpf__strerror_entry(EINVAL, "%s: Are you root and runing a CONFIG_BPF_SYSCALL kernel?", | |
349 | emsg) | |
350 | bpf__strerror_end(buf, size); | |
351 | return 0; | |
352 | } |