/*
* Class: sun_jvm_hotspot_debugger_proc_ProcDebuggerLocal
* Method: readBytesFromProcess0
* Signature: (JJ)Lsun/jvm/hotspot/debugger/ReadResult;
*/
JNIEXPORT jbyteArray JNICALL Java_sun_jvm_hotspot_debugger_proc_ProcDebuggerLocal_readBytesFromProcess0
(JNIEnv *env, jobject this_obj, jlong address, jlong numBytes) {
jbyteArray array = env->NewByteArray(numBytes);
CHECK_EXCEPTION_(0);
jboolean isCopy;
jbyte* bufPtr = env->GetByteArrayElements(array, &isCopy);
CHECK_EXCEPTION_(0);
jlong ps_prochandle_ptr = env->GetLongField(this_obj, ps_prochandle_ptr_ID);
ps_err_e ret = ps_pread((struct ps_prochandle*) ps_prochandle_ptr,
(psaddr_t)address, bufPtr, (size_t)numBytes);
if(ret != PS_OK) {
// Part of workaround for 4705086.
jint libjvm_fd = env->GetIntField(this_obj, libjvm_fd_ID);
jlong libjvm_text_start = env->GetLongField(this_obj, libjvm_text_start_ID);
jlong libjvm_text_size = env->GetLongField(this_obj, libjvm_text_size_ID);
// get the file descriptor for libjvm.so
jlong offset = address - libjvm_text_start;
// do bounds check to verify that the given address is in
// libjvm text
if (offset >= libjvm_text_size || offset < 0) {
env->ReleaseByteArrayElements(array, bufPtr, JNI_COMMIT);
// the address given is not in libjvm[_g].so text
return jbyteArray(0);
}
ssize_t bytes_read = pread(libjvm_fd, bufPtr, numBytes, (off_t)offset);
if (bytes_read != (ssize_t) numBytes) {
env->ReleaseByteArrayElements(array, bufPtr, JNI_COMMIT);
return jbyteArray(0);
}
}
env->ReleaseByteArrayElements(array, bufPtr, JNI_COMMIT);
return array;
}
/*
* Class: sun_jvm_hotspot_debugger_proc_ProcDebuggerLocal
* Method: readBytesFromProcess0
* Signature: (JJ)[B
* Description: read bytes from debuggee process/core
*/
JNIEXPORT jbyteArray JNICALL Java_sun_jvm_hotspot_debugger_proc_ProcDebuggerLocal_readBytesFromProcess0
(JNIEnv *env, jobject this_obj, jlong address, jlong numBytes) {
jbyteArray array = env->NewByteArray(numBytes);
CHECK_EXCEPTION_(0);
jboolean isCopy;
jbyte* bufPtr = env->GetByteArrayElements(array, &isCopy);
CHECK_EXCEPTION_(0);
jlong p_ps_prochandle = env->GetLongField(this_obj, p_ps_prochandle_ID);
ps_err_e ret = ps_pread((struct ps_prochandle*) p_ps_prochandle,
(psaddr_t)address, bufPtr, (size_t)numBytes);
if (ret != PS_OK) {
// part of the class sharing workaround. try shared heap area
int classes_jsa_fd = env->GetIntField(this_obj, classes_jsa_fd_ID);
if (classes_jsa_fd != -1 && address != (jlong)0) {
print_debug("read failed at 0x%lx, attempting shared heap area\n", (long) address);
struct FileMapHeader* pheader = (struct FileMapHeader*) env->GetLongField(this_obj, p_file_map_header_ID);
// walk through the shared mappings -- we just have 4 of them.
// so, linear walking is okay.
for (int m = 0; m < NUM_SHARED_MAPS; m++) {
// We can skip the non-read-only maps. These are mapped as MAP_PRIVATE
// and hence will be read by libproc. Besides, the file copy may be
// stale because the process might have modified those pages.
if (pheader->_space[m]._read_only) {
jlong baseAddress = (jlong) (uintptr_t) pheader->_space[m]._base;
size_t usedSize = pheader->_space[m]._used;
if (address >= baseAddress && address < (baseAddress + usedSize)) {
// the given address falls in this shared heap area
print_debug("found shared map at 0x%lx\n", (long) baseAddress);
// If more data is asked than actually mapped from file, we need to zero fill
// till the end-of-page boundary. But, java array new does that for us. we just
// need to read as much as data available.
#define MIN2(x, y) (((x) < (y))? (x) : (y))
jlong diff = address - baseAddress;
jlong bytesToRead = MIN2(numBytes, usedSize - diff);
off_t offset = pheader->_space[m]._file_offset + off_t(diff);
ssize_t bytesRead = pread(classes_jsa_fd, bufPtr, bytesToRead, offset);
if (bytesRead != bytesToRead) {
env->ReleaseByteArrayElements(array, bufPtr, JNI_ABORT);
print_debug("shared map read failed\n");
return jbyteArray(0);
} else {
print_debug("shared map read succeeded\n");
env->ReleaseByteArrayElements(array, bufPtr, 0);
return array;
}
} // is in current map
} // is read only map
} // for shared maps
} // classes_jsa_fd != -1
env->ReleaseByteArrayElements(array, bufPtr, JNI_ABORT);
return jbyteArray(0);
} else {
env->ReleaseByteArrayElements(array, bufPtr, 0);
return array;
}
}
