1 // SPDX-License-Identifier: GPL-2.0 2 #include <linux/compiler.h> 3 #include <sys/types.h> 4 #include <stdio.h> 5 #include <string.h> 6 #include <stdlib.h> 7 #include <err.h> 8 #include <jvmti.h> 9 #ifdef HAVE_JVMTI_CMLR 10 #include <jvmticmlr.h> 11 #endif 12 #include <limits.h> 13 14 #include "jvmti_agent.h" 15 16 static int has_line_numbers; 17 void *jvmti_agent; 18 19 static void print_error(jvmtiEnv *jvmti, const char *msg, jvmtiError ret) 20 { 21 char *err_msg = NULL; 22 jvmtiError err; 23 err = (*jvmti)->GetErrorName(jvmti, ret, &err_msg); 24 if (err == JVMTI_ERROR_NONE) { 25 warnx("%s failed with %s", msg, err_msg); 26 (*jvmti)->Deallocate(jvmti, (unsigned char *)err_msg); 27 } else { 28 warnx("%s failed with an unknown error %d", msg, ret); 29 } 30 } 31 32 #ifdef HAVE_JVMTI_CMLR 33 static jvmtiError 34 do_get_line_numbers(jvmtiEnv *jvmti, void *pc, jmethodID m, jint bci, 35 jvmti_line_info_t *tab, jint *nr) 36 { 37 jint i, lines = 0; 38 jint nr_lines = 0; 39 jvmtiLineNumberEntry *loc_tab = NULL; 40 jvmtiError ret; 41 42 ret = (*jvmti)->GetLineNumberTable(jvmti, m, &nr_lines, &loc_tab); 43 if (ret != JVMTI_ERROR_NONE) { 44 print_error(jvmti, "GetLineNumberTable", ret); 45 return ret; 46 } 47 48 for (i = 0; i < nr_lines; i++) { 49 if (loc_tab[i].start_location < bci) { 50 tab[lines].pc = (unsigned long)pc; 51 tab[lines].line_number = loc_tab[i].line_number; 52 tab[lines].discrim = 0; /* not yet used */ 53 tab[lines].methodID = m; 54 lines++; 55 } else { 56 break; 57 } 58 } 59 (*jvmti)->Deallocate(jvmti, (unsigned char *)loc_tab); 60 *nr = lines; 61 return JVMTI_ERROR_NONE; 62 } 63 64 static jvmtiError 65 get_line_numbers(jvmtiEnv *jvmti, const void *compile_info, jvmti_line_info_t **tab, int *nr_lines) 66 { 67 const jvmtiCompiledMethodLoadRecordHeader *hdr; 68 jvmtiCompiledMethodLoadInlineRecord *rec; 69 jvmtiLineNumberEntry *lne = NULL; 70 PCStackInfo *c; 71 jint nr, ret; 72 int nr_total = 0; 73 int i, lines_total = 0; 74 75 if (!(tab && nr_lines)) 76 return JVMTI_ERROR_NULL_POINTER; 77 78 /* 79 * Phase 1 -- get the number of lines necessary 80 */ 81 for (hdr = compile_info; hdr != NULL; hdr = hdr->next) { 82 if (hdr->kind == JVMTI_CMLR_INLINE_INFO) { 83 rec = (jvmtiCompiledMethodLoadInlineRecord *)hdr; 84 for (i = 0; i < rec->numpcs; i++) { 85 c = rec->pcinfo + i; 86 nr = 0; 87 /* 88 * unfortunately, need a tab to get the number of lines! 89 */ 90 ret = (*jvmti)->GetLineNumberTable(jvmti, c->methods[0], &nr, &lne); 91 if (ret == JVMTI_ERROR_NONE) { 92 /* free what was allocated for nothing */ 93 (*jvmti)->Deallocate(jvmti, (unsigned char *)lne); 94 nr_total += (int)nr; 95 } else { 96 print_error(jvmti, "GetLineNumberTable", ret); 97 } 98 } 99 } 100 } 101 102 if (nr_total == 0) 103 return JVMTI_ERROR_NOT_FOUND; 104 105 /* 106 * Phase 2 -- allocate big enough line table 107 */ 108 *tab = malloc(nr_total * sizeof(**tab)); 109 if (!*tab) 110 return JVMTI_ERROR_OUT_OF_MEMORY; 111 112 for (hdr = compile_info; hdr != NULL; hdr = hdr->next) { 113 if (hdr->kind == JVMTI_CMLR_INLINE_INFO) { 114 rec = (jvmtiCompiledMethodLoadInlineRecord *)hdr; 115 for (i = 0; i < rec->numpcs; i++) { 116 c = rec->pcinfo + i; 117 nr = 0; 118 ret = do_get_line_numbers(jvmti, c->pc, 119 c->methods[0], 120 c->bcis[0], 121 *tab + lines_total, 122 &nr); 123 if (ret == JVMTI_ERROR_NONE) 124 lines_total += nr; 125 } 126 } 127 } 128 *nr_lines = lines_total; 129 return JVMTI_ERROR_NONE; 130 } 131 #else /* HAVE_JVMTI_CMLR */ 132 133 static jvmtiError 134 get_line_numbers(jvmtiEnv *jvmti __maybe_unused, const void *compile_info __maybe_unused, 135 jvmti_line_info_t **tab __maybe_unused, int *nr_lines __maybe_unused) 136 { 137 return JVMTI_ERROR_NONE; 138 } 139 #endif /* HAVE_JVMTI_CMLR */ 140 141 static void 142 copy_class_filename(const char * class_sign, const char * file_name, char * result, size_t max_length) 143 { 144 /* 145 * Assume path name is class hierarchy, this is a common practice with Java programs 146 */ 147 if (*class_sign == 'L') { 148 int j, i = 0; 149 char *p = strrchr(class_sign, '/'); 150 if (p) { 151 /* drop the 'L' prefix and copy up to the final '/' */ 152 for (i = 0; i < (p - class_sign); i++) 153 result[i] = class_sign[i+1]; 154 } 155 /* 156 * append file name, we use loops and not string ops to avoid modifying 157 * class_sign which is used later for the symbol name 158 */ 159 for (j = 0; i < (max_length - 1) && file_name && j < strlen(file_name); j++, i++) 160 result[i] = file_name[j]; 161 162 result[i] = '\0'; 163 } else { 164 /* fallback case */ 165 size_t file_name_len = strlen(file_name); 166 strncpy(result, file_name, file_name_len < max_length ? file_name_len : max_length); 167 } 168 } 169 170 static jvmtiError 171 get_source_filename(jvmtiEnv *jvmti, jmethodID methodID, char ** buffer) 172 { 173 jvmtiError ret; 174 jclass decl_class; 175 char *file_name = NULL; 176 char *class_sign = NULL; 177 char fn[PATH_MAX]; 178 size_t len; 179 180 ret = (*jvmti)->GetMethodDeclaringClass(jvmti, methodID, &decl_class); 181 if (ret != JVMTI_ERROR_NONE) { 182 print_error(jvmti, "GetMethodDeclaringClass", ret); 183 return ret; 184 } 185 186 ret = (*jvmti)->GetSourceFileName(jvmti, decl_class, &file_name); 187 if (ret != JVMTI_ERROR_NONE) { 188 print_error(jvmti, "GetSourceFileName", ret); 189 return ret; 190 } 191 192 ret = (*jvmti)->GetClassSignature(jvmti, decl_class, &class_sign, NULL); 193 if (ret != JVMTI_ERROR_NONE) { 194 print_error(jvmti, "GetClassSignature", ret); 195 goto free_file_name_error; 196 } 197 198 copy_class_filename(class_sign, file_name, fn, PATH_MAX); 199 len = strlen(fn); 200 *buffer = malloc((len + 1) * sizeof(char)); 201 if (!*buffer) { 202 print_error(jvmti, "GetClassSignature", ret); 203 ret = JVMTI_ERROR_OUT_OF_MEMORY; 204 goto free_class_sign_error; 205 } 206 strcpy(*buffer, fn); 207 ret = JVMTI_ERROR_NONE; 208 209 free_class_sign_error: 210 (*jvmti)->Deallocate(jvmti, (unsigned char *)class_sign); 211 free_file_name_error: 212 (*jvmti)->Deallocate(jvmti, (unsigned char *)file_name); 213 214 return ret; 215 } 216 217 static jvmtiError 218 fill_source_filenames(jvmtiEnv *jvmti, int nr_lines, 219 const jvmti_line_info_t * line_tab, 220 char ** file_names) 221 { 222 int index; 223 jvmtiError ret; 224 225 for (index = 0; index < nr_lines; ++index) { 226 ret = get_source_filename(jvmti, line_tab[index].methodID, &(file_names[index])); 227 if (ret != JVMTI_ERROR_NONE) 228 return ret; 229 } 230 231 return JVMTI_ERROR_NONE; 232 } 233 234 static void JNICALL 235 compiled_method_load_cb(jvmtiEnv *jvmti, 236 jmethodID method, 237 jint code_size, 238 void const *code_addr, 239 jint map_length, 240 jvmtiAddrLocationMap const *map, 241 const void *compile_info) 242 { 243 jvmti_line_info_t *line_tab = NULL; 244 char ** line_file_names = NULL; 245 jclass decl_class; 246 char *class_sign = NULL; 247 char *func_name = NULL; 248 char *func_sign = NULL; 249 char *file_name = NULL; 250 char fn[PATH_MAX]; 251 uint64_t addr = (uint64_t)(uintptr_t)code_addr; 252 jvmtiError ret; 253 int nr_lines = 0; /* in line_tab[] */ 254 size_t len; 255 int output_debug_info = 0; 256 257 ret = (*jvmti)->GetMethodDeclaringClass(jvmti, method, 258 &decl_class); 259 if (ret != JVMTI_ERROR_NONE) { 260 print_error(jvmti, "GetMethodDeclaringClass", ret); 261 return; 262 } 263 264 if (has_line_numbers && map && map_length) { 265 ret = get_line_numbers(jvmti, compile_info, &line_tab, &nr_lines); 266 if (ret != JVMTI_ERROR_NONE) { 267 warnx("jvmti: cannot get line table for method"); 268 nr_lines = 0; 269 } else if (nr_lines > 0) { 270 line_file_names = malloc(sizeof(char*) * nr_lines); 271 if (!line_file_names) { 272 warnx("jvmti: cannot allocate space for line table method names"); 273 } else { 274 memset(line_file_names, 0, sizeof(char*) * nr_lines); 275 ret = fill_source_filenames(jvmti, nr_lines, line_tab, line_file_names); 276 if (ret != JVMTI_ERROR_NONE) { 277 warnx("jvmti: fill_source_filenames failed"); 278 } else { 279 output_debug_info = 1; 280 } 281 } 282 } 283 } 284 285 ret = (*jvmti)->GetSourceFileName(jvmti, decl_class, &file_name); 286 if (ret != JVMTI_ERROR_NONE) { 287 print_error(jvmti, "GetSourceFileName", ret); 288 goto error; 289 } 290 291 ret = (*jvmti)->GetClassSignature(jvmti, decl_class, 292 &class_sign, NULL); 293 if (ret != JVMTI_ERROR_NONE) { 294 print_error(jvmti, "GetClassSignature", ret); 295 goto error; 296 } 297 298 ret = (*jvmti)->GetMethodName(jvmti, method, &func_name, 299 &func_sign, NULL); 300 if (ret != JVMTI_ERROR_NONE) { 301 print_error(jvmti, "GetMethodName", ret); 302 goto error; 303 } 304 305 copy_class_filename(class_sign, file_name, fn, PATH_MAX); 306 307 /* 308 * write source line info record if we have it 309 */ 310 if (output_debug_info) 311 if (jvmti_write_debug_info(jvmti_agent, addr, nr_lines, line_tab, (const char * const *) line_file_names)) 312 warnx("jvmti: write_debug_info() failed"); 313 314 len = strlen(func_name) + strlen(class_sign) + strlen(func_sign) + 2; 315 { 316 char str[len]; 317 snprintf(str, len, "%s%s%s", class_sign, func_name, func_sign); 318 319 if (jvmti_write_code(jvmti_agent, str, addr, code_addr, code_size)) 320 warnx("jvmti: write_code() failed"); 321 } 322 error: 323 (*jvmti)->Deallocate(jvmti, (unsigned char *)func_name); 324 (*jvmti)->Deallocate(jvmti, (unsigned char *)func_sign); 325 (*jvmti)->Deallocate(jvmti, (unsigned char *)class_sign); 326 (*jvmti)->Deallocate(jvmti, (unsigned char *)file_name); 327 free(line_tab); 328 while (line_file_names && (nr_lines > 0)) { 329 if (line_file_names[nr_lines - 1]) { 330 free(line_file_names[nr_lines - 1]); 331 } 332 nr_lines -= 1; 333 } 334 free(line_file_names); 335 } 336 337 static void JNICALL 338 code_generated_cb(jvmtiEnv *jvmti, 339 char const *name, 340 void const *code_addr, 341 jint code_size) 342 { 343 uint64_t addr = (uint64_t)(unsigned long)code_addr; 344 int ret; 345 346 ret = jvmti_write_code(jvmti_agent, name, addr, code_addr, code_size); 347 if (ret) 348 warnx("jvmti: write_code() failed for code_generated"); 349 } 350 351 JNIEXPORT jint JNICALL 352 Agent_OnLoad(JavaVM *jvm, char *options, void *reserved __maybe_unused) 353 { 354 jvmtiEventCallbacks cb; 355 jvmtiCapabilities caps1; 356 jvmtiJlocationFormat format; 357 jvmtiEnv *jvmti = NULL; 358 jint ret; 359 360 jvmti_agent = jvmti_open(); 361 if (!jvmti_agent) { 362 warnx("jvmti: open_agent failed"); 363 return -1; 364 } 365 366 /* 367 * Request a JVMTI interface version 1 environment 368 */ 369 ret = (*jvm)->GetEnv(jvm, (void *)&jvmti, JVMTI_VERSION_1); 370 if (ret != JNI_OK) { 371 warnx("jvmti: jvmti version 1 not supported"); 372 return -1; 373 } 374 375 /* 376 * acquire method_load capability, we require it 377 * request line numbers (optional) 378 */ 379 memset(&caps1, 0, sizeof(caps1)); 380 caps1.can_generate_compiled_method_load_events = 1; 381 382 ret = (*jvmti)->AddCapabilities(jvmti, &caps1); 383 if (ret != JVMTI_ERROR_NONE) { 384 print_error(jvmti, "AddCapabilities", ret); 385 return -1; 386 } 387 ret = (*jvmti)->GetJLocationFormat(jvmti, &format); 388 if (ret == JVMTI_ERROR_NONE && format == JVMTI_JLOCATION_JVMBCI) { 389 memset(&caps1, 0, sizeof(caps1)); 390 caps1.can_get_line_numbers = 1; 391 caps1.can_get_source_file_name = 1; 392 ret = (*jvmti)->AddCapabilities(jvmti, &caps1); 393 if (ret == JVMTI_ERROR_NONE) 394 has_line_numbers = 1; 395 } else if (ret != JVMTI_ERROR_NONE) 396 print_error(jvmti, "GetJLocationFormat", ret); 397 398 399 memset(&cb, 0, sizeof(cb)); 400 401 cb.CompiledMethodLoad = compiled_method_load_cb; 402 cb.DynamicCodeGenerated = code_generated_cb; 403 404 ret = (*jvmti)->SetEventCallbacks(jvmti, &cb, sizeof(cb)); 405 if (ret != JVMTI_ERROR_NONE) { 406 print_error(jvmti, "SetEventCallbacks", ret); 407 return -1; 408 } 409 410 ret = (*jvmti)->SetEventNotificationMode(jvmti, JVMTI_ENABLE, 411 JVMTI_EVENT_COMPILED_METHOD_LOAD, NULL); 412 if (ret != JVMTI_ERROR_NONE) { 413 print_error(jvmti, "SetEventNotificationMode(METHOD_LOAD)", ret); 414 return -1; 415 } 416 417 ret = (*jvmti)->SetEventNotificationMode(jvmti, JVMTI_ENABLE, 418 JVMTI_EVENT_DYNAMIC_CODE_GENERATED, NULL); 419 if (ret != JVMTI_ERROR_NONE) { 420 print_error(jvmti, "SetEventNotificationMode(CODE_GENERATED)", ret); 421 return -1; 422 } 423 return 0; 424 } 425 426 JNIEXPORT void JNICALL 427 Agent_OnUnload(JavaVM *jvm __maybe_unused) 428 { 429 int ret; 430 431 ret = jvmti_close(jvmti_agent); 432 if (ret) 433 errx(1, "Error: op_close_agent()"); 434 } 435