/*******************************************************************************
 * Copyright (c) 2011 Nokia and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 * Nokia - Initial API and implementation
 *******************************************************************************/

#include "BreakpointsService.h"
#include "ContextManager.h"

#include <string>

#include "TCFHeaders.h"
#include "TCFChannel.h"

#include "AgentUtils.h"
#include "ContextManager.h"
#include "EventClientNotifier.h"
#include "Logger.h"

#include "WinHWBkptMgr.h"
#include "WinProcess.h"
#include "WinThread.h"

static const char * sServiceName = "Breakpoints";

static const unsigned char	sBreakInst = 0xCC;

bool BreakpointsService::sServiceInstalled = false;

//
// The static function reads the context ids for a breakpoint
//
static void read_id_array(InputStream* inp, void* arg)
{
	TCFInputStream inpStream(inp);
	std::vector<std::string>* ids = (std::vector<std::string>*)(arg);
	std::string str = inpStream.readString();
	ids->push_back(str);
}

//
// This static function is used to read all the breakpoint properties or attributes
//
static void read_breakpoint_attr(InputStream * inp, const char * nm, void * arg) {
	TCFInputStream inpStream(inp);
	TBreakpoint* attrs = (TBreakpoint*)arg;

	if (::strcmp(nm, "AccessMode") == 0) {
		attrs->accessMode = (TCFAccessMode)inpStream.readULong();
		return;
	}

	if (::strcmp(nm, "BreakpointType") == 0) {
		std::string type = inpStream.readString();
		if (type.compare("Auto") == 0) {
			attrs->bpType = type_Auto;
		} else if (type.compare("Software") == 0) {
			attrs->bpType = type_Software;
		} else if (type.compare("Hardware") == 0) {
			attrs->bpType = type_Hardware;
		}
		return;
	}

	if (::strcmp(nm, "ContextIds") == 0) {
		json_read_array(inp,read_id_array,&attrs->iContextIds);
		return;
	}

	if (::strcmp(nm, "Enabled") == 0) {
		attrs->enabled = json_read_boolean(inp);
		return;
	}

	if (::strcmp(nm, "ID") == 0) {
		attrs->hostBreakPointId = inpStream.readString();
		return;
	}

	if (::strcmp(nm, "Location") == 0) {
		std::string location(inpStream.readString());
		// atoi fails on large unsigned ints.
		// this will also handle negative numbers, though.
		::sscanf(location.c_str(), "%u", (unsigned int*)&attrs->address);
		return;
	}

	if (::strcmp(nm, "Size") == 0) {
		attrs->size = inpStream.readULong();
		return;
	}

	json_skip_object(inp);
}

//
// BreakpointService::BreakpointService()
//
BreakpointsService::BreakpointsService(Protocol* proto)
  : TCFService(proto)
{
	AddCommand("add", CommandAddBreakpoint);
	AddCommand("remove", CommandRemoveBreakpoint);

	sServiceInstalled = true;
}

//
//  static function to get the service name
//
const char* BreakpointsService::GetName() {
	return sServiceName;
}

// 
// BreakpointService::CommandAddBreakpoint()
//
void BreakpointsService::CommandAddBreakpoint(const char* token, Channel* c) {
	LogTrace("BreakpointService::command_add_Breakpoint", "token: %s", token);

	TCFChannel channel(c);
	TBreakpoint* breakInfo = new TBreakpoint();
	json_read_struct(&c->inp, read_breakpoint_attr, breakInfo);

	channel.readZero();
	channel.readComplete();

	// EDC in 3.x > 20100831 will pass a thread-specific bp (if known) at the end of the list.
	// For now we stick with process-specific breakpoints.
	// TODO: see if we want thread-specific breakpoints in the future.
	std::string contextID
	  = breakInfo->iContextIds.empty() ? "" : breakInfo->iContextIds.front();

	Context* context = ContextManager::findContext(contextID);

	WinProcess*& proc_context = breakInfo->process;
	WinThread* thread_context = NULL;

	if ((proc_context = dynamic_cast<WinProcess*>(context)) != NULL) {
		// id is a process
	} else if ((thread_context = dynamic_cast<WinThread*>(context)) != NULL) {
		// id is a thread
		proc_context = dynamic_cast<WinProcess*>(ContextManager::findContext(
				thread_context->GetParentID()));
	}

	if (!proc_context || !proc_context->IsDebugging()) {
		channel.writeCompleteReply(token, ERR_INV_CONTEXT);
		return;
	}

	// "thread_context" is not required.
	if (thread_context && !thread_context->IsDebugging()) {
		channel.writeCompleteReply(token, ERR_INV_CONTEXT);
		return;
	}

	if (!breakInfo->enabled) {
		trace(LOG_ALWAYS, "!!! cannot set disabled breakpoints");
		channel.writeCompleteReply(token, ERR_UNSUPPORTED);
		return;
	}

	int err;
	if (ACCESSMODE_EXECUTE == breakInfo->accessMode)
		err = InsertBreak(breakInfo);
	else
		err = InsertWatch(breakInfo);

	if (err == 0) {
		trace(LOG_ALWAYS, "Breakpoint added for ID = %s", breakInfo->hostBreakPointId.c_str());
		sBreakPointMap[breakInfo->hostBreakPointId] = breakInfo;
	}

	channel.writeCompleteReply(token, err);
}

//
// BreakpointService::CommandRemoveBreakpoint()
//
void BreakpointsService::CommandRemoveBreakpoint(const char* token, Channel* c) {
    LogTrace("BreakpointService::command_remove_Breakpoint", "token: %s", token);
    
    TCFChannel channel(c); 
    int err = 0;
    int overallError = 0;
    std::vector<std::string> breakIdList;
    json_read_array(&c->inp, read_id_array, &breakIdList);
    
    channel.readZero();
    channel.readComplete();
    
	std::vector<std::string>::iterator iter ;
	for (iter = breakIdList.begin(); iter != breakIdList.end(); ) {
		TID2BreakpointMap::iterator it = sBreakPointMap.find(*iter++);
		if (it == sBreakPointMap.end()) {
			if (!overallError)
				overallError = ERR_OTHER;
			continue;
		}
		
		TBreakpoint* bp = it->second;
		sBreakPointMap.erase(it->first);

		if (ACCESSMODE_EXECUTE == bp->accessMode)
			err = ClearBreak(bp);
		else
			err = ClearWatch(bp);

		delete bp;

		// ignore "not found" from the driver, since some breakpoints
		// are removed automatically on process kill / detach / etc.
		if (err != 0 && err != ERR_OTHER && !overallError)
			overallError = err;
	}

	channel.writeCompleteReply(token, overallError);
}

/*
 * Is the Breakpoints service installed in the agent ?
 */
bool BreakpointsService::ServiceInstalled() {
	return sServiceInstalled;
}

/*
 * Insert a software breakpoint in a process.
 */
int BreakpointsService::InsertBreak(const TBreakpoint* bpInfo) {
	const HANDLE& procHandle = bpInfo->process->GetProcessHandle();

	// save byte at breakpoint address.
	if (! ::ReadProcessMemory(procHandle, (LPCVOID)bpInfo->address, (LPVOID)&bpInfo->originalByte, 1, NULL))
		return ::GetLastError();

	// write breakpoint (INT3) to memory
	if (! ::WriteProcessMemory(procHandle, (LPVOID)bpInfo->address, (LPVOID)&sBreakInst, 1, NULL))
		return ::GetLastError();

	// make sure original instruction isn't already in cache
	if (! ::FlushInstructionCache(procHandle, (LPCVOID)bpInfo->address, 1))
		return ::GetLastError();

	return 0;
}

/*
 * Clear a breakpoint from a process.
 */
int BreakpointsService::ClearBreak(const TBreakpoint* bpInfo) {
	const HANDLE& procHandle = bpInfo->process->GetProcessHandle();

	// write original byte back over top of (INT3) in memory
	if (! ::WriteProcessMemory(procHandle, (LPVOID)bpInfo->address, (LPVOID)&bpInfo->originalByte, 1, NULL))
		return ::GetLastError();

	// make sure bp instruction isn't already in cache
	if (! ::FlushInstructionCache(procHandle, (LPCVOID)bpInfo->address, 1))
		return ::GetLastError();

	return 0;
}

/*
 * establish a hardware watchpoint using the hardware debug registers
 */
int BreakpointsService::InsertWatch(TBreakpoint* bpInfo) {
	return WinHWBkptMgr::SetHardwareBreak(bpInfo);
}

/*
 * clear the hardware debug register for a given watchpoint
 */
int BreakpointsService::ClearWatch(TBreakpoint* bpInfo) {
	return WinHWBkptMgr::ClearHardwareBreak(bpInfo);
}

/*
 * find if there's a breakpoint at the given address in a process.
 */
TBreakpoint* BreakpointsService::FindBreakpointByAddress(
		const HANDLE& processHandle, const ContextAddress address) {
	TID2BreakpointMap::iterator iter;
	for (iter = sBreakPointMap.begin(); iter != sBreakPointMap.end(); iter++) {
		TBreakpoint* bp = iter->second;
		if (ACCESSMODE_EXECUTE == bp->accessMode
			&& bp->process && processHandle == bp->process->GetProcessHandle()	// same process
			&& address == bp->address)
		{
			return bp;
		}
	}
	return NULL;
}

/*
 * find if there's a watchpoint at the given address in a process.
 */
TBreakpoint*
BreakpointsService::FindWatchpointByAddress(const HANDLE& processHandle,
		ContextAddress address)
{
	TID2BreakpointMap::iterator iter;
	for (iter = sBreakPointMap.begin(); iter != sBreakPointMap.end(); iter++) {
		TBreakpoint* wp = iter->second;
		if (ACCESSMODE_EXECUTE != wp->accessMode
			&& wp->process && processHandle == wp->process->GetProcessHandle()	// same process
			&& wp->address <= address && address < wp->address+wp->size)
		{
			return wp;
		}
	}
	return NULL;
}

/*
 * Given a memory buffer read from a process, remove any breakpoint instructions added by debugger in the buffer.
 */
void BreakpointsService::RemoveBreakpointsFromMemoryRead(
		const HANDLE& processHandle, ContextAddress address, char* memBuffer,
		const unsigned long size) {
	TID2BreakpointMap::iterator iter;
	for (iter = sBreakPointMap.begin(); iter != sBreakPointMap.end(); iter++) {
		TBreakpoint* bp = iter->second;
		if (ACCESSMODE_EXECUTE == bp->accessMode
			&& bp->process && processHandle == bp->process->GetProcessHandle()	// same process
			&& address <= bp->address && address+size > bp->address)	// bp falls in the buffer
		{
			char *byteToChange = memBuffer + (bp->address - address);
			*byteToChange = bp->originalByte;
		}
	}
}

/*
 * Given a memory buffer that has been writen to a process, re-inssert any breakpoints in the buffer range.
 */
void BreakpointsService::ReInsertBreakpointsAfterMemoryWrite(
		const HANDLE& processHandle, ContextAddress address, char* memBuffer,
		const unsigned long size) {
	TID2BreakpointMap::iterator iter;
	for (iter = sBreakPointMap.begin(); iter != sBreakPointMap.end(); iter++) {
		TBreakpoint* bp = iter->second;
		if (ACCESSMODE_EXECUTE == bp->accessMode
			&& bp->process && processHandle == bp->process->GetProcessHandle()	// same process
			&& address <= bp->address && address+size > bp->address)	// bp falls in the buffer
		{
			InsertBreak(bp);
		}
	}
}