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 #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 }