LXR linux/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
  17static int has_line_numbers;
  18void *jvmti_agent;
  19
  20static 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
  34static jvmtiError
  35do_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
  72static jvmtiError
  73get_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
 129static jvmtiError
 130get_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
 137static void
 138copy_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
 165static jvmtiError
 166get_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
 204free_class_sign_error:
 205        (*jvmti)->Deallocate(jvmti, (unsigned char *)class_sign);
 206free_file_name_error:
 207        (*jvmti)->Deallocate(jvmti, (unsigned char *)file_name);
 208
 209        return ret;
 210}
 211
 212static jvmtiError
 213fill_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
 229static void JNICALL
 230compiled_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        }
 309error:
 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
 323static void JNICALL
 324code_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
 337JNIEXPORT jint JNICALL
 338Agent_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
 412JNIEXPORT void JNICALL
 413Agent_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}
 421