| 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 |
| 22 | |
| 23 | #include <link.h> |
| 24 | #include <limits.h> |
| 25 | #include <stdio.h> |
| 26 | #include <stdint.h> |
| 27 | #include <stdlib.h> |
| 28 | #include <sys/types.h> |
| 29 | #include <unistd.h> |
| 30 | |
| 31 | #include <lttng/ust-elf.h> |
| 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 bin_info_data { |
| 46 | void *owner; |
| 47 | void *base_addr_ptr; |
| 48 | const char *resolved_path; |
| 49 | char *dbg_file; |
| 50 | uint8_t *build_id; |
| 51 | uint64_t memsz; |
| 52 | size_t build_id_len; |
| 53 | int vdso; |
| 54 | uint32_t crc; |
| 55 | uint8_t is_pic; |
| 56 | uint8_t has_build_id; |
| 57 | uint8_t has_debug_link; |
| 58 | }; |
| 59 | |
| 60 | typedef void (*tracepoint_cb)(struct lttng_session *session, void *priv); |
| 61 | |
| 62 | /* |
| 63 | * Trace statedump event into all sessions owned by the caller thread |
| 64 | * for which statedump is pending. |
| 65 | */ |
| 66 | static |
| 67 | int trace_statedump_event(tracepoint_cb tp_cb, void *owner, void *priv) |
| 68 | { |
| 69 | struct cds_list_head *sessionsp; |
| 70 | struct lttng_session *session; |
| 71 | |
| 72 | sessionsp = _lttng_get_sessions(); |
| 73 | cds_list_for_each_entry(session, sessionsp, node) { |
| 74 | if (session->owner != owner) |
| 75 | continue; |
| 76 | if (!session->statedump_pending) |
| 77 | continue; |
| 78 | tp_cb(session, priv); |
| 79 | } |
| 80 | return 0; |
| 81 | } |
| 82 | |
| 83 | static |
| 84 | void trace_bin_info_cb(struct lttng_session *session, void *priv) |
| 85 | { |
| 86 | struct bin_info_data *bin_data = (struct bin_info_data *) priv; |
| 87 | |
| 88 | tracepoint(lttng_ust_statedump, bin_info, |
| 89 | session, bin_data->base_addr_ptr, |
| 90 | bin_data->resolved_path, bin_data->memsz, |
| 91 | bin_data->is_pic, bin_data->has_build_id, |
| 92 | bin_data->has_debug_link); |
| 93 | } |
| 94 | |
| 95 | static |
| 96 | void trace_build_id_cb(struct lttng_session *session, void *priv) |
| 97 | { |
| 98 | struct bin_info_data *bin_data = (struct bin_info_data *) priv; |
| 99 | |
| 100 | tracepoint(lttng_ust_statedump, build_id, |
| 101 | session, bin_data->base_addr_ptr, |
| 102 | bin_data->build_id, bin_data->build_id_len); |
| 103 | } |
| 104 | |
| 105 | static |
| 106 | void trace_debug_link_cb(struct lttng_session *session, void *priv) |
| 107 | { |
| 108 | struct bin_info_data *bin_data = (struct bin_info_data *) priv; |
| 109 | |
| 110 | tracepoint(lttng_ust_statedump, debug_link, |
| 111 | session, bin_data->base_addr_ptr, |
| 112 | bin_data->dbg_file, bin_data->crc); |
| 113 | } |
| 114 | |
| 115 | static |
| 116 | void trace_start_cb(struct lttng_session *session, void *priv) |
| 117 | { |
| 118 | tracepoint(lttng_ust_statedump, start, session); |
| 119 | } |
| 120 | |
| 121 | static |
| 122 | void trace_end_cb(struct lttng_session *session, void *priv) |
| 123 | { |
| 124 | tracepoint(lttng_ust_statedump, end, session); |
| 125 | } |
| 126 | |
| 127 | static |
| 128 | int get_elf_info(struct bin_info_data *bin_data) |
| 129 | { |
| 130 | struct lttng_ust_elf *elf; |
| 131 | int ret = 0, found; |
| 132 | |
| 133 | elf = lttng_ust_elf_create(bin_data->resolved_path); |
| 134 | if (!elf) { |
| 135 | ret = -1; |
| 136 | goto end; |
| 137 | } |
| 138 | |
| 139 | ret = lttng_ust_elf_get_memsz(elf, &bin_data->memsz); |
| 140 | if (ret) { |
| 141 | goto end; |
| 142 | } |
| 143 | |
| 144 | found = 0; |
| 145 | ret = lttng_ust_elf_get_build_id(elf, &bin_data->build_id, |
| 146 | &bin_data->build_id_len, |
| 147 | &found); |
| 148 | if (ret) { |
| 149 | goto end; |
| 150 | } |
| 151 | bin_data->has_build_id = !!found; |
| 152 | found = 0; |
| 153 | ret = lttng_ust_elf_get_debug_link(elf, &bin_data->dbg_file, |
| 154 | &bin_data->crc, |
| 155 | &found); |
| 156 | if (ret) { |
| 157 | goto end; |
| 158 | } |
| 159 | bin_data->has_debug_link = !!found; |
| 160 | |
| 161 | bin_data->is_pic = lttng_ust_elf_is_pic(elf); |
| 162 | |
| 163 | end: |
| 164 | lttng_ust_elf_destroy(elf); |
| 165 | return ret; |
| 166 | } |
| 167 | |
| 168 | static |
| 169 | int trace_baddr(struct bin_info_data *bin_data) |
| 170 | { |
| 171 | int ret = 0; |
| 172 | |
| 173 | if (!bin_data->vdso) { |
| 174 | ret = get_elf_info(bin_data); |
| 175 | if (ret) { |
| 176 | goto end; |
| 177 | } |
| 178 | } else { |
| 179 | bin_data->memsz = 0; |
| 180 | bin_data->has_build_id = 0; |
| 181 | bin_data->has_debug_link = 0; |
| 182 | } |
| 183 | |
| 184 | ret = trace_statedump_event(trace_bin_info_cb, bin_data->owner, |
| 185 | bin_data); |
| 186 | if (ret) { |
| 187 | goto end; |
| 188 | } |
| 189 | |
| 190 | if (bin_data->has_build_id) { |
| 191 | ret = trace_statedump_event( |
| 192 | trace_build_id_cb, bin_data->owner, bin_data); |
| 193 | free(bin_data->build_id); |
| 194 | if (ret) { |
| 195 | goto end; |
| 196 | } |
| 197 | } |
| 198 | |
| 199 | if (bin_data->has_debug_link) { |
| 200 | ret = trace_statedump_event( |
| 201 | trace_debug_link_cb, bin_data->owner, bin_data); |
| 202 | free(bin_data->dbg_file); |
| 203 | if (ret) { |
| 204 | goto end; |
| 205 | } |
| 206 | } |
| 207 | |
| 208 | end: |
| 209 | return ret; |
| 210 | } |
| 211 | |
| 212 | static |
| 213 | int trace_statedump_start(void *owner) |
| 214 | { |
| 215 | return trace_statedump_event(trace_start_cb, owner, NULL); |
| 216 | } |
| 217 | |
| 218 | static |
| 219 | int trace_statedump_end(void *owner) |
| 220 | { |
| 221 | return trace_statedump_event(trace_end_cb, owner, NULL); |
| 222 | } |
| 223 | |
| 224 | static |
| 225 | int extract_bin_info_events(struct dl_phdr_info *info, size_t size, void *_data) |
| 226 | { |
| 227 | int j, ret = 0; |
| 228 | struct dl_iterate_data *data = _data; |
| 229 | |
| 230 | /* |
| 231 | * UST lock nests within dynamic loader lock. |
| 232 | * |
| 233 | * Hold this lock across handling of the entire module to |
| 234 | * protect memory allocation at early process start, due to |
| 235 | * interactions with libc-wrapper lttng malloc instrumentation. |
| 236 | */ |
| 237 | if (ust_lock()) { |
| 238 | goto end; |
| 239 | } |
| 240 | |
| 241 | for (j = 0; j < info->dlpi_phnum; j++) { |
| 242 | struct bin_info_data bin_data; |
| 243 | char resolved_path[PATH_MAX]; |
| 244 | void *base_addr_ptr; |
| 245 | |
| 246 | if (info->dlpi_phdr[j].p_type != PT_LOAD) |
| 247 | continue; |
| 248 | |
| 249 | /* Calculate virtual memory address of the loadable segment */ |
| 250 | base_addr_ptr = (void *) info->dlpi_addr + |
| 251 | info->dlpi_phdr[j].p_vaddr; |
| 252 | |
| 253 | if ((info->dlpi_name == NULL || info->dlpi_name[0] == 0)) { |
| 254 | /* |
| 255 | * Only the first phdr without a dlpi_name |
| 256 | * encountered is considered as the program |
| 257 | * executable. The rest are vdsos. |
| 258 | */ |
| 259 | if (!data->exec_found) { |
| 260 | ssize_t path_len; |
| 261 | data->exec_found = 1; |
| 262 | |
| 263 | /* |
| 264 | * Use /proc/self/exe to resolve the |
| 265 | * executable's full path. |
| 266 | */ |
| 267 | path_len = readlink("/proc/self/exe", |
| 268 | resolved_path, |
| 269 | PATH_MAX - 1); |
| 270 | if (path_len <= 0) |
| 271 | break; |
| 272 | |
| 273 | resolved_path[path_len] = '\0'; |
| 274 | bin_data.vdso = 0; |
| 275 | } else { |
| 276 | snprintf(resolved_path, PATH_MAX - 1, "[vdso]"); |
| 277 | bin_data.vdso = 1; |
| 278 | } |
| 279 | } else { |
| 280 | /* |
| 281 | * For regular dl_phdr_info entries check if |
| 282 | * the path to the binary really exists. If not, |
| 283 | * treat as vdso and use dlpi_name as 'path'. |
| 284 | */ |
| 285 | if (!realpath(info->dlpi_name, resolved_path)) { |
| 286 | snprintf(resolved_path, PATH_MAX - 1, "[%s]", |
| 287 | info->dlpi_name); |
| 288 | bin_data.vdso = 1; |
| 289 | } else { |
| 290 | bin_data.vdso = 0; |
| 291 | } |
| 292 | } |
| 293 | |
| 294 | bin_data.owner = data->owner; |
| 295 | bin_data.base_addr_ptr = base_addr_ptr; |
| 296 | bin_data.resolved_path = resolved_path; |
| 297 | ret = trace_baddr(&bin_data); |
| 298 | break; |
| 299 | } |
| 300 | end: |
| 301 | ust_unlock(); |
| 302 | return ret; |
| 303 | } |
| 304 | |
| 305 | /* |
| 306 | * Generate a statedump of base addresses of all shared objects loaded |
| 307 | * by the traced application, as well as for the application's |
| 308 | * executable itself. |
| 309 | */ |
| 310 | static |
| 311 | int do_baddr_statedump(void *owner) |
| 312 | { |
| 313 | struct dl_iterate_data data; |
| 314 | |
| 315 | if (getenv("LTTNG_UST_WITHOUT_BADDR_STATEDUMP")) |
| 316 | return 0; |
| 317 | |
| 318 | data.owner = owner; |
| 319 | data.exec_found = 0; |
| 320 | /* |
| 321 | * Iterate through the list of currently loaded shared objects and |
| 322 | * generate events for loadable segments using |
| 323 | * extract_bin_info_events. |
| 324 | */ |
| 325 | dl_iterate_phdr(extract_bin_info_events, &data); |
| 326 | |
| 327 | return 0; |
| 328 | } |
| 329 | |
| 330 | /* |
| 331 | * Generate a statedump of a given traced application. A statedump is |
| 332 | * delimited by start and end events. For a given (process, session) |
| 333 | * pair, begin/end events are serialized and will match. However, in a |
| 334 | * session, statedumps from different processes may be |
| 335 | * interleaved. The vpid context should be used to identify which |
| 336 | * events belong to which process. |
| 337 | */ |
| 338 | int do_lttng_ust_statedump(void *owner) |
| 339 | { |
| 340 | trace_statedump_start(owner); |
| 341 | do_baddr_statedump(owner); |
| 342 | trace_statedump_end(owner); |
| 343 | |
| 344 | return 0; |
| 345 | } |
| 346 | |
| 347 | void lttng_ust_statedump_init(void) |
| 348 | { |
| 349 | __tracepoints__init(); |
| 350 | __tracepoints__ptrs_init(); |
| 351 | __lttng_events_init__lttng_ust_statedump(); |
| 352 | } |
| 353 | |
| 354 | void lttng_ust_statedump_destroy(void) |
| 355 | { |
| 356 | __lttng_events_exit__lttng_ust_statedump(); |
| 357 | __tracepoints__ptrs_destroy(); |
| 358 | __tracepoints__destroy(); |
| 359 | } |