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