tools/perf/jvmti/libjvmti.c

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