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cf73e0fe AB |
1 | /* |
2 | * Copyright (C) 2013 Paul Woegerer <paul_woegerer@mentor.com> | |
3 | * Copyright (C) 2015 Antoine Busque <abusque@efficios.com> | |
4 | * | |
5 | * This library is free software; you can redistribute it and/or | |
6 | * modify it under the terms of the GNU Lesser General Public | |
7 | * License as published by the Free Software Foundation; either | |
8 | * version 2.1 of the License, or (at your option) any later version. | |
9 | * | |
10 | * This library is distributed in the hope that it will be useful, | |
11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
13 | * Lesser General Public License for more details. | |
14 | * | |
15 | * You should have received a copy of the GNU Lesser General Public | |
16 | * License along with this library; if not, write to the Free Software | |
17 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
18 | */ | |
19 | ||
20 | #define _LGPL_SOURCE | |
21 | #define _GNU_SOURCE | |
cf73e0fe | 22 | |
8e2aed3f | 23 | #include <link.h> |
cf73e0fe | 24 | #include <limits.h> |
cf73e0fe | 25 | #include <stdio.h> |
8e2aed3f AB |
26 | #include <stdint.h> |
27 | #include <stdlib.h> | |
28 | #include <sys/types.h> | |
29 | #include <unistd.h> | |
cf73e0fe | 30 | |
8e2aed3f | 31 | #include <lttng/ust-elf.h> |
cf73e0fe AB |
32 | #include "lttng-tracer-core.h" |
33 | #include "lttng-ust-statedump.h" | |
34 | ||
35 | #define TRACEPOINT_DEFINE | |
36 | #define TRACEPOINT_CREATE_PROBES | |
37 | #define TP_SESSION_CHECK | |
38 | #include "lttng-ust-statedump-provider.h" | |
39 | ||
40 | struct dl_iterate_data { | |
41 | void *owner; | |
42 | int exec_found; | |
43 | }; | |
44 | ||
45 | struct soinfo_data { | |
46 | void *owner; | |
47 | void *base_addr_ptr; | |
48 | const char *resolved_path; | |
8e2aed3f AB |
49 | char *dbg_file; |
50 | uint8_t *build_id; | |
51 | uint64_t memsz; | |
52 | size_t build_id_len; | |
cf73e0fe | 53 | int vdso; |
8e2aed3f | 54 | uint32_t crc; |
cf73e0fe AB |
55 | }; |
56 | ||
57 | typedef void (*tracepoint_cb)(struct lttng_session *session, void *priv); | |
58 | ||
59 | /* | |
60 | * Trace statedump event into all sessions owned by the caller thread | |
61 | * for which statedump is pending. | |
62 | */ | |
63 | static | |
64 | int trace_statedump_event(tracepoint_cb tp_cb, void *owner, void *priv) | |
65 | { | |
66 | struct cds_list_head *sessionsp; | |
67 | struct lttng_session *session; | |
68 | ||
cf73e0fe AB |
69 | sessionsp = _lttng_get_sessions(); |
70 | cds_list_for_each_entry(session, sessionsp, node) { | |
71 | if (session->owner != owner) | |
72 | continue; | |
73 | if (!session->statedump_pending) | |
74 | continue; | |
75 | tp_cb(session, priv); | |
76 | } | |
cf73e0fe AB |
77 | return 0; |
78 | } | |
79 | ||
80 | static | |
81 | void trace_soinfo_cb(struct lttng_session *session, void *priv) | |
82 | { | |
83 | struct soinfo_data *so_data = (struct soinfo_data *) priv; | |
84 | ||
85 | tracepoint(lttng_ust_statedump, soinfo, | |
8e2aed3f AB |
86 | session, so_data->base_addr_ptr, |
87 | so_data->resolved_path, so_data->memsz); | |
88 | } | |
89 | ||
90 | static | |
91 | void trace_build_id_cb(struct lttng_session *session, void *priv) | |
92 | { | |
93 | struct soinfo_data *so_data = (struct soinfo_data *) priv; | |
94 | ||
95 | tracepoint(lttng_ust_statedump, build_id, | |
96 | session, so_data->base_addr_ptr, | |
97 | so_data->build_id, so_data->build_id_len); | |
98 | } | |
99 | ||
100 | static | |
101 | void trace_debug_link_cb(struct lttng_session *session, void *priv) | |
102 | { | |
103 | struct soinfo_data *so_data = (struct soinfo_data *) priv; | |
104 | ||
105 | tracepoint(lttng_ust_statedump, debug_link, | |
106 | session, so_data->base_addr_ptr, | |
107 | so_data->dbg_file, so_data->crc); | |
cf73e0fe AB |
108 | } |
109 | ||
110 | static | |
111 | void trace_start_cb(struct lttng_session *session, void *priv) | |
112 | { | |
113 | tracepoint(lttng_ust_statedump, start, session); | |
114 | } | |
115 | ||
116 | static | |
117 | void trace_end_cb(struct lttng_session *session, void *priv) | |
118 | { | |
119 | tracepoint(lttng_ust_statedump, end, session); | |
120 | } | |
121 | ||
8e2aed3f AB |
122 | static |
123 | int get_elf_info(struct soinfo_data *so_data, int *has_build_id, | |
124 | int *has_debug_link) { | |
125 | struct lttng_ust_elf *elf; | |
126 | int ret = 0; | |
127 | ||
128 | elf = lttng_ust_elf_create(so_data->resolved_path); | |
129 | if (!elf) { | |
130 | ret = -1; | |
131 | goto end; | |
132 | } | |
133 | ||
134 | ret = lttng_ust_elf_get_memsz(elf, &so_data->memsz); | |
135 | if (ret) { | |
136 | goto end; | |
137 | } | |
138 | ||
139 | ret = lttng_ust_elf_get_build_id(elf, &so_data->build_id, | |
140 | &so_data->build_id_len, has_build_id); | |
141 | if (ret) { | |
142 | goto end; | |
143 | } | |
144 | ret = lttng_ust_elf_get_debug_link(elf, &so_data->dbg_file, | |
145 | &so_data->crc, has_debug_link); | |
146 | if (ret) { | |
147 | goto end; | |
148 | } | |
149 | ||
150 | end: | |
151 | lttng_ust_elf_destroy(elf); | |
152 | return ret; | |
153 | } | |
154 | ||
cf73e0fe AB |
155 | static |
156 | int trace_baddr(struct soinfo_data *so_data) | |
157 | { | |
8e2aed3f AB |
158 | int ret = 0, has_build_id = 0, has_debug_link = 0; |
159 | ||
160 | if (!so_data->vdso) { | |
161 | ret = get_elf_info(so_data, &has_build_id, &has_debug_link); | |
162 | if (ret) { | |
163 | goto end; | |
164 | } | |
165 | } else { | |
166 | so_data->memsz = 0; | |
167 | } | |
168 | ||
169 | ret = trace_statedump_event(trace_soinfo_cb, so_data->owner, so_data); | |
170 | if (ret) { | |
171 | goto end; | |
172 | } | |
cf73e0fe | 173 | |
8e2aed3f AB |
174 | if (has_build_id) { |
175 | ret = trace_statedump_event( | |
176 | trace_build_id_cb, so_data->owner, so_data); | |
177 | free(so_data->build_id); | |
178 | if (ret) { | |
179 | goto end; | |
180 | } | |
cf73e0fe AB |
181 | } |
182 | ||
8e2aed3f AB |
183 | if (has_debug_link) { |
184 | ret = trace_statedump_event( | |
185 | trace_debug_link_cb, so_data->owner, so_data); | |
186 | free(so_data->dbg_file); | |
187 | if (ret) { | |
188 | goto end; | |
189 | } | |
190 | } | |
cf73e0fe | 191 | |
8e2aed3f AB |
192 | end: |
193 | return ret; | |
cf73e0fe AB |
194 | } |
195 | ||
196 | static | |
197 | int trace_statedump_start(void *owner) | |
198 | { | |
199 | return trace_statedump_event(trace_start_cb, owner, NULL); | |
200 | } | |
201 | ||
202 | static | |
203 | int trace_statedump_end(void *owner) | |
204 | { | |
205 | return trace_statedump_event(trace_end_cb, owner, NULL); | |
206 | } | |
207 | ||
208 | static | |
209 | int extract_soinfo_events(struct dl_phdr_info *info, size_t size, void *_data) | |
210 | { | |
d34e6761 | 211 | int j, ret = 0; |
cf73e0fe AB |
212 | struct dl_iterate_data *data = _data; |
213 | ||
d34e6761 MD |
214 | /* |
215 | * UST lock nests within dynamic loader lock. | |
216 | * | |
217 | * Hold this lock across handling of the entire module to | |
218 | * protect memory allocation at early process start, due to | |
219 | * interactions with libc-wrapper lttng malloc instrumentation. | |
220 | */ | |
221 | if (ust_lock()) { | |
222 | goto end; | |
223 | } | |
224 | ||
cf73e0fe AB |
225 | for (j = 0; j < info->dlpi_phnum; j++) { |
226 | struct soinfo_data so_data; | |
227 | char resolved_path[PATH_MAX]; | |
228 | void *base_addr_ptr; | |
229 | ||
230 | if (info->dlpi_phdr[j].p_type != PT_LOAD) | |
231 | continue; | |
232 | ||
233 | /* Calculate virtual memory address of the loadable segment */ | |
234 | base_addr_ptr = (void *) info->dlpi_addr + | |
235 | info->dlpi_phdr[j].p_vaddr; | |
236 | ||
237 | if ((info->dlpi_name == NULL || info->dlpi_name[0] == 0)) { | |
238 | /* | |
239 | * Only the first phdr without a dlpi_name | |
240 | * encountered is considered as the program | |
241 | * executable. The rest are vdsos. | |
242 | */ | |
243 | if (!data->exec_found) { | |
244 | ssize_t path_len; | |
245 | data->exec_found = 1; | |
246 | ||
247 | /* | |
248 | * Use /proc/self/exe to resolve the | |
249 | * executable's full path. | |
250 | */ | |
251 | path_len = readlink("/proc/self/exe", | |
252 | resolved_path, | |
253 | PATH_MAX - 1); | |
254 | if (path_len <= 0) | |
255 | break; | |
256 | ||
257 | resolved_path[path_len] = '\0'; | |
258 | so_data.vdso = 0; | |
259 | } else { | |
260 | snprintf(resolved_path, PATH_MAX - 1, "[vdso]"); | |
261 | so_data.vdso = 1; | |
262 | } | |
263 | } else { | |
264 | /* | |
265 | * For regular dl_phdr_info entries check if | |
266 | * the path to the SO really exists. If not, | |
267 | * treat as vdso and use dlpi_name as 'path'. | |
268 | */ | |
269 | if (!realpath(info->dlpi_name, resolved_path)) { | |
270 | snprintf(resolved_path, PATH_MAX - 1, "[%s]", | |
271 | info->dlpi_name); | |
272 | so_data.vdso = 1; | |
89be5359 AB |
273 | } else { |
274 | so_data.vdso = 0; | |
cf73e0fe AB |
275 | } |
276 | } | |
277 | ||
278 | so_data.owner = data->owner; | |
279 | so_data.base_addr_ptr = base_addr_ptr; | |
280 | so_data.resolved_path = resolved_path; | |
d34e6761 MD |
281 | ret = trace_baddr(&so_data); |
282 | break; | |
cf73e0fe | 283 | } |
d34e6761 MD |
284 | end: |
285 | ust_unlock(); | |
286 | return ret; | |
cf73e0fe AB |
287 | } |
288 | ||
289 | /* | |
290 | * Generate a statedump of base addresses of all shared objects loaded | |
291 | * by the traced application, as well as for the application's | |
292 | * executable itself. | |
293 | */ | |
294 | static | |
295 | int do_baddr_statedump(void *owner) | |
296 | { | |
297 | struct dl_iterate_data data; | |
298 | ||
299 | if (getenv("LTTNG_UST_WITHOUT_BADDR_STATEDUMP")) | |
300 | return 0; | |
301 | ||
302 | data.owner = owner; | |
303 | data.exec_found = 0; | |
304 | /* | |
305 | * Iterate through the list of currently loaded shared objects and | |
306 | * generate events for loadable segments using | |
307 | * extract_soinfo_events. | |
308 | */ | |
309 | dl_iterate_phdr(extract_soinfo_events, &data); | |
310 | ||
311 | return 0; | |
312 | } | |
313 | ||
314 | /* | |
315 | * Generate a statedump of a given traced application. A statedump is | |
316 | * delimited by start and end events. For a given (process, session) | |
317 | * pair, begin/end events are serialized and will match. However, in a | |
318 | * session, statedumps from different processes may be | |
319 | * interleaved. The vpid context should be used to identify which | |
320 | * events belong to which process. | |
321 | */ | |
322 | int do_lttng_ust_statedump(void *owner) | |
323 | { | |
324 | trace_statedump_start(owner); | |
325 | do_baddr_statedump(owner); | |
326 | trace_statedump_end(owner); | |
327 | ||
328 | return 0; | |
329 | } | |
330 | ||
331 | void lttng_ust_statedump_init(void) | |
332 | { | |
333 | __tracepoints__init(); | |
334 | __tracepoints__ptrs_init(); | |
335 | __lttng_events_init__lttng_ust_statedump(); | |
336 | } | |
337 | ||
338 | void lttng_ust_statedump_destroy(void) | |
339 | { | |
340 | __lttng_events_exit__lttng_ust_statedump(); | |
341 | __tracepoints__ptrs_destroy(); | |
342 | __tracepoints__destroy(); | |
343 | } |