tools/perf/jvmti/libjvmti.c

   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 }