| 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 soinfo_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 | }; |
| 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 | |
| 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 | } |
| 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, |
| 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); |
| 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 | |
| 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 | |
| 155 | static |
| 156 | int trace_baddr(struct soinfo_data *so_data) |
| 157 | { |
| 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 | } |
| 173 | |
| 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 | } |
| 181 | } |
| 182 | |
| 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 | } |
| 191 | |
| 192 | end: |
| 193 | return ret; |
| 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 | { |
| 211 | int j, ret = 0; |
| 212 | struct dl_iterate_data *data = _data; |
| 213 | |
| 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 | |
| 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; |
| 273 | } else { |
| 274 | so_data.vdso = 0; |
| 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; |
| 281 | ret = trace_baddr(&so_data); |
| 282 | break; |
| 283 | } |
| 284 | end: |
| 285 | ust_unlock(); |
| 286 | return ret; |
| 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 | } |