#include <string.h>
#include <stdlib.h>

#include "jni.h"
#include "jvmti.h"

void check_jvmti_error(jvmtiEnv *jvmti, jvmtiError errnum, const char *str) {
  if (errnum != JVMTI_ERROR_NONE) {
    char *errnum_str;

    errnum_str = NULL;
    (void)(*jvmti)->GetErrorName(jvmti, errnum, &errnum_str);

    printf("ERROR: JVMTI: %d(%s): %s\n", errnum,
      (errnum_str == NULL ? "Unknown" : errnum_str),
      (str == NULL ? "" : str));
  }
}

void printProperty(jvmtiEnv *jvmti, const char *prop) {
  char *value;
  jvmtiError err = (*jvmti)->GetSystemProperty(jvmti, prop, &value);
  check_jvmti_error(jvmti, err, prop);
  printf("%s = %s\n", prop, value);
  (*jvmti)->Deallocate(jvmti, (unsigned char*)value);
}

JNIEXPORT jint JNICALL Agent_OnLoad(JavaVM *vm, char *options, void *reserved) {
  jvmtiError err;
  jvmtiEnv *jvmti;
  size_t len;
  char *bcp;
  char *temp;

  (*vm)->GetEnv(vm, (void **)&jvmti, JVMTI_VERSION_1_1);

  err = (*jvmti)->GetSystemProperty(jvmti, "sun.boot.class.path", &bcp);
  check_jvmti_error(jvmti, err, "GetSystemProperty");

  len = strlen(bcp) + 20;
  temp = (char*)malloc(len);
  sprintf_s(temp, len, "C:\\patch\\java.base;%s", bcp);
  (*jvmti)->Deallocate(jvmti, (unsigned char*)bcp);

  err = (*jvmti)->SetSystemProperty(jvmti, "sun.boot.class.path", temp);
  check_jvmti_error(jvmti, err, "SetSystemProperty");
  free(temp);

  printProperty(jvmti, "sun.boot.class.path");
  printProperty(jvmti, "jdk.boot.class.path.append");

  printf("Calling AddToBootstrapClassLoaderSearch\n");
  err = (*jvmti)->AddToBootstrapClassLoaderSearch(jvmti, "C:\\XWork\\MinAgent\\target\\MinAgent.jar");
  check_jvmti_error(jvmti, err, "AddToBootstrapClassLoaderSearch");

  printProperty(jvmti, "sun.boot.class.path");
  printProperty(jvmti, "jdk.boot.class.path.append");

  return 0;
}