/*

 * Copyright (c) 2012, 2018, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 *

 */

#include "sun_jvm_hotspot_asm_Disassembler.h"

/*

 *  This file implements a binding between Java and the hsdis

 *  The only platform dependent pieces of the code for doing

 *  dlopen/dlsym to find the entry point in hsdis.  All the rest is

 *  standard JNI code.

 */

#ifdef _WINDOWS

// Disable CRT security warning against _snprintf

#pragma warning (disable : 4996)

#define snprintf  _snprintf

#define vsnprintf _vsnprintf

#include <windows.h>

#include <sys/types.h>

#include <sys/stat.h>

#ifdef _DEBUG

#include <crtdbg.h>

#endif

#else

#include <string.h>

#include <dlfcn.h>

#ifndef __APPLE__

#include <link.h>

#endif

#endif

#include <limits.h>

#include <stdio.h>

#include <stdarg.h>

#include <stdlib.h>

#include <errno.h>

#ifdef _WINDOWS

#define JVM_MAXPATHLEN _MAX_PATH

#else

#include <sys/param.h>

#define JVM_MAXPATHLEN MAXPATHLEN

#endif

#ifdef _WINDOWS

static int getLastErrorString(char *buf, size_t len)

{

    long errval;

    if ((errval = GetLastError()) != 0)

    {

      /* DOS error */

      size_t n = (size_t)FormatMessage(

            FORMAT_MESSAGE_FROM_SYSTEM|FORMAT_MESSAGE_IGNORE_INSERTS,

            NULL,

            errval,

            0,

            buf,

            (DWORD)len,

            NULL);

      if (n > 3) {

        /* Drop final '.', CR, LF */

        if (buf[n - 1] == '\n') n--;

        if (buf[n - 1] == '\r') n--;

        if (buf[n - 1] == '.') n--;

        buf[n] = '\0';

      }

      return (int)n;

    }

    if (errno != 0)

    {

      /* C runtime error that has no corresponding DOS error code */

      strerror_s(buf, len, errno);

      return strlen(buf);

    }

    return 0;

}

#endif /* _WINDOWS */

/*

 * Class:     sun_jvm_hotspot_asm_Disassembler

 * Method:    load_library

 * Signature: (Ljava/lang/String;)L

 */

JNIEXPORT jlong JNICALL Java_sun_jvm_hotspot_asm_Disassembler_load_1library(JNIEnv * env,

                                                                           jclass disclass,

                                                                           jstring jrepath_s,

                                                                           jstring libname_s) {

  uintptr_t func = 0;

  const char *error_message = NULL;

  const char *jrepath = NULL;

  const char *libname = NULL;

  char buffer[JVM_MAXPATHLEN];

#ifdef _WINDOWS

  HINSTANCE hsdis_handle = (HINSTANCE) NULL;

#else

  void* hsdis_handle = NULL;

#endif

  jrepath = (*env)->GetStringUTFChars(env, jrepath_s, NULL); // like $JAVA_HOME/jre/lib/sparc/

  if (jrepath == NULL || (*env)->ExceptionOccurred(env)) {

    return 0;

  }

  libname = (*env)->GetStringUTFChars(env, libname_s, NULL);

  if (libname == NULL || (*env)->ExceptionOccurred(env)) {

    (*env)->ReleaseStringUTFChars(env, jrepath_s, jrepath);

    return 0;

  }

  /* Load the hsdis library */

#ifdef _WINDOWS

  hsdis_handle = LoadLibrary(libname);

  if (hsdis_handle == NULL) {

    snprintf(buffer, sizeof(buffer), "%s%s", jrepath, libname);

    hsdis_handle = LoadLibrary(buffer);

  }

  if (hsdis_handle != NULL) {

    func = (uintptr_t)GetProcAddress(hsdis_handle, "decode_instructions_virtual");

  }

  if (func == 0) {

    getLastErrorString(buffer, sizeof(buffer));

    error_message = buffer;

  }

#else

  hsdis_handle = dlopen(libname, RTLD_LAZY | RTLD_GLOBAL);

  if (hsdis_handle == NULL) {

    snprintf(buffer, sizeof(buffer), "%s%s", jrepath, libname);

    hsdis_handle = dlopen(buffer, RTLD_LAZY | RTLD_GLOBAL);

  }

  if (hsdis_handle != NULL) {

    func = (uintptr_t)dlsym(hsdis_handle, "decode_instructions_virtual");

  }

  if (func == 0) {

    error_message = dlerror();

  }

#endif

  (*env)->ReleaseStringUTFChars(env, libname_s, libname);

  (*env)->ReleaseStringUTFChars(env, jrepath_s, jrepath);

  if (func == 0) {

    /* Couldn't find entry point.  error_message should contain some

     * platform dependent error message.

     */

    jclass eclass = (*env)->FindClass(env, "sun/jvm/hotspot/debugger/DebuggerException");

    if ((*env)->ExceptionOccurred(env)) {

      /* Can't throw exception, probably OOM, so silently return 0 */

      return (jlong) 0;

    }

    (*env)->ThrowNew(env, eclass, error_message);

  }

  return (jlong)func;

}

/* signature of decode_instructions_virtual from hsdis.h */

typedef void* (*decode_func)(uintptr_t start_va, uintptr_t end_va,

                             unsigned char* start, uintptr_t length,

                             void* (*event_callback)(void*, const char*, void*),

                             void* event_stream,

                             int (*printf_callback)(void*, const char*, ...),

                             void* printf_stream,

                             const char* options,

                             int newline);

/* container for call back state when decoding instructions */

typedef struct {

  JNIEnv* env;

  jobject dis;

  jobject visitor;

  jmethodID handle_event;

  jmethodID raw_print;

  char buffer[4096];

} decode_env;

/* event callback binding to Disassembler.handleEvent */

static void* event_to_env(void* env_pv, const char* event, void* arg) {

  jlong result = 0;

  decode_env* denv = (decode_env*)env_pv;

  JNIEnv* env = denv->env;

  jstring event_string = (*env)->NewStringUTF(env, event);

  if ((*env)->ExceptionOccurred(env)) {

    return NULL;

  }

  result = (*env)->CallLongMethod(env, denv->dis, denv->handle_event, denv->visitor,

                                  event_string, (jlong) (uintptr_t)arg);

  if ((*env)->ExceptionOccurred(env)) {

    /* ignore exceptions for now */

    (*env)->ExceptionClear(env);

    return NULL;

  }

  return (void*)(uintptr_t)result;

}

/* printing callback binding to Disassembler.rawPrint */

static int printf_to_env(void* env_pv, const char* format, ...) {

  jstring output;

  va_list ap;

  int cnt;

  decode_env* denv = (decode_env*)env_pv;

  JNIEnv* env = denv->env;

  size_t flen = strlen(format);

  const char* raw = NULL;

  if (flen == 0)  return 0;

  if (flen < 2 ||

      strchr(format, '%') == NULL) {

    raw = format;

  } else if (format[0] == '%' && format[1] == '%' &&

             strchr(format+2, '%') == NULL) {

    // happens a lot on machines with names like %foo

    flen--;

    raw = format+1;

  }

  if (raw != NULL) {

    jstring output = (*env)->NewStringUTF(env, raw);

    if (!(*env)->ExceptionOccurred(env)) {

      /* make sure that UTF allocation doesn't cause OOM */

      (*env)->CallVoidMethod(env, denv->dis, denv->raw_print, denv->visitor, output);

    }

    if ((*env)->ExceptionOccurred(env)) {

      /* ignore exceptions for now */

        (*env)->ExceptionClear(env);

    }

    return (int) flen;

  }

  va_start(ap, format);

  cnt = vsnprintf(denv->buffer, sizeof(denv->buffer), format, ap);

  va_end(ap);

  output = (*env)->NewStringUTF(env, denv->buffer);

  if (!(*env)->ExceptionOccurred(env)) {

    /* make sure that UTF allocation doesn't cause OOM */

    (*env)->CallVoidMethod(env, denv->dis, denv->raw_print, denv->visitor, output);

  }

  if ((*env)->ExceptionOccurred(env)) {

    /* ignore exceptions for now */

    (*env)->ExceptionClear(env);

  }

  return cnt;

}

/*

 * Class:     sun_jvm_hotspot_asm_Disassembler

 * Method:    decode

 * Signature: (Lsun/jvm/hotspot/asm/InstructionVisitor;J[BLjava/lang/String;J)V

 */

JNIEXPORT void JNICALL Java_sun_jvm_hotspot_asm_Disassembler_decode(JNIEnv * env,

                                                                    jobject dis,

                                                                    jobject visitor,

                                                                    jlong startPc,

                                                                    jbyteArray code,

                                                                    jstring options_s,

                                                                    jlong decode_instructions_virtual) {

  jbyte *start = NULL;

  jbyte *end = NULL;

  jclass disclass = NULL;

  const char *options = NULL;

  decode_env denv;

  start = (*env)->GetByteArrayElements(env, code, NULL);

  if ((*env)->ExceptionOccurred(env)) {

    return;

  }

  end = start + (*env)->GetArrayLength(env, code);

  options = (*env)->GetStringUTFChars(env, options_s, NULL);

  if ((*env)->ExceptionOccurred(env)) {

    (*env)->ReleaseByteArrayElements(env, code, start, JNI_ABORT);

    return;

  }

  disclass = (*env)->GetObjectClass(env, dis);

  denv.env = env;

  denv.dis = dis;

  denv.visitor = visitor;

  /* find Disassembler.handleEvent callback */

  denv.handle_event = (*env)->GetMethodID(env, disclass, "handleEvent",

                                          "(Lsun/jvm/hotspot/asm/InstructionVisitor;Ljava/lang/String;J)J");

  if ((*env)->ExceptionOccurred(env)) {

    (*env)->ReleaseByteArrayElements(env, code, start, JNI_ABORT);

    (*env)->ReleaseStringUTFChars(env, options_s, options);

    return;

  }

  /* find Disassembler.rawPrint callback */

  denv.raw_print = (*env)->GetMethodID(env, disclass, "rawPrint",

                                       "(Lsun/jvm/hotspot/asm/InstructionVisitor;Ljava/lang/String;)V");

  if ((*env)->ExceptionOccurred(env)) {

    (*env)->ReleaseByteArrayElements(env, code, start, JNI_ABORT);

    (*env)->ReleaseStringUTFChars(env, options_s, options);

    return;

  }

  /* decode the buffer */

  (*(decode_func)(uintptr_t)decode_instructions_virtual)((uintptr_t) startPc,

                                                         startPc + end - start,

                                                         (unsigned char*)start,

                                                         end - start,

                                                         &event_to_env,  (void*) &denv,

                                                         &printf_to_env, (void*) &denv,

                                                         options, 0 /* newline */);

  /* cleanup */

  (*env)->ReleaseByteArrayElements(env, code, start, JNI_ABORT);

  (*env)->ReleaseStringUTFChars(env, options_s, options);

}