BlitzNext/Linker/lib/image_util.cpp

#include "image_util.hpp"
#include <fstream>
#include <istream>
#include <ostream>
#include <vector>

#ifndef DEMO

#pragma pack(push, 1)
struct Head {
	short machine, num_sects;
	int   timedata, sym_table, num_syms;
	short opt_size, chars;
};

struct Opts {
	short magic;
	char  major, minor;
	int   code_size, data_size, udata_size;
	int   entry, code_base, data_base;

	int   image_base, sect_align, file_align;
	short major_os, minor_os, major_image, minor_image, major_subsys, minor_subsys;

	int reserved;
	int image_size, headers_size, checksum;

	short subsys, dllchars;

	int stack_reserve, stack_commit, heap_reserve, heap_commit, loadflags;

	int dir_entries;
};

struct DDir {
	int rva, size;
};

struct Sect {
	char  name[8];
	int   virt_size, virt_addr; //in mem
	int   data_size, data_addr; //on disk
	int   relocs, lines;        //file ptrs
	short num_relocs, num_lines;
	int   chars;
};

struct Rdir {
	int   chars, timedata;
	short major, minor, num_names, num_ids;
};

struct Rent {
	int id, data;
};

struct Rdat {
	int addr, size, cp, zero;
};

#pragma pack(pop)

struct Rsrc {
	int                id;
	void*              data;
	int                data_sz;
	std::vector<Rsrc*> kids;

	Rsrc(int id, Rsrc* p) : id(id), data(0), data_sz(0)
	{
		if (p)
			p->kids.push_back(this);
		//		cout<<"res id:"<<dec<<id<<hex<<endl;
	}

	~Rsrc()
	{
		for (; kids.size(); kids.pop_back())
			delete kids.back();
		delete data;
	}
};

struct Section {
	Sect  sect;
	char* data;

	Section() : data(0) {}
	~Section()
	{
		delete[] data;
	}
};

static char* stub;
static int   stub_sz;

static Head* head;
static int   head_sz;

static Opts* opts;
static int   opts_sz;

static DDir* ddir;
static int   ddir_sz;

static std::vector<Section*> sections;

static Rsrc* rsrc_root;

static const char* img_file;

static void openRsrcDir(Section* s, int off, Rsrc* p)
{
	char* data = (char*)s->data;

	Rdir* dir = (Rdir*)(data + off);
	Rent* ent = (Rent*)(dir + 1);
	for (int k = 0; k < dir->num_ids; ++ent, ++k) {
		Rsrc* r = new Rsrc(ent->id, p);
		if (ent->data < 0) { //a node - offset is another dir
			openRsrcDir(s, ent->data & 0x7fffffff, r);
		} else { //a leaf
			Rdat* dat = (Rdat*)(data + ent->data);
			//			cout<<"dat addr:"<<dat->addr<<" size:"<<dat->size<<endl;
			int   sz   = dat->size;
			void* src  = dat->addr - s->sect.virt_addr + data;
			void* dest = new char[sz];
			memcpy(dest, src, sz);
			r->data    = dest;
			r->data_sz = sz;
		}
	}
}

static void openRsrcTree(Section* s)
{
	rsrc_root = new Rsrc(0, 0);
	openRsrcDir(s, 0, rsrc_root);
}

static int rsrcSize(Rsrc* r)
{
	if (r->data)
		return (sizeof(Rdat) + r->data_sz + 7) & ~7;
	int sz = sizeof(Rdir);
	for (int k = 0; k < r->kids.size(); ++k) {
		sz += sizeof(Rent) + rsrcSize(r->kids[k]);
	}
	return sz;
}

static void closeRsrcDir(Section* s, int off, Rsrc* p)
{
	int t, k;

	char* data = (char*)s->data;

	Rdir* dir = (Rdir*)(data + off);
	memset(dir, 0, sizeof(Rdir));
	dir->num_ids = p->kids.size();
	Rent* ent    = (Rent*)(dir + 1);

	//to end of dir...
	off += sizeof(Rdir) + sizeof(Rent) * p->kids.size();

	t = off;

	//write entries
	for (k = 0; k < p->kids.size(); ++ent, ++k) {
		Rsrc* r   = p->kids[k];
		ent->id   = r->id;
		ent->data = t;
		if (!r->data)
			ent->data |= 0x80000000;
		t += rsrcSize(r);
	}

	t = off;

	//write kids...
	for (k = 0; k < p->kids.size(); ++k) {
		Rsrc* r = p->kids[k];
		if (!r->data) {
			closeRsrcDir(s, t, r);
		} else {
			Rdat* dat = (Rdat*)(data + t);
			dat->addr = s->sect.virt_addr + t + sizeof(Rdat);
			dat->size = r->data_sz;
			dat->zero = dat->cp = 0;
			memcpy(data + t + sizeof(Rdat), r->data, r->data_sz);
		}
		t += rsrcSize(r);
	}
}

static int fileAlign(int n)
{
	return (n + (opts->file_align - 1)) & ~(opts->file_align - 1);
}

static int sectAlign(int n)
{
	return (n + (opts->sect_align - 1)) & ~(opts->sect_align - 1);
}

static void closeRsrcTree(Section* s)
{
	int virt_sz = rsrcSize(rsrc_root);
	int data_sz = fileAlign(virt_sz);

	int virt_delta = sectAlign(virt_sz) - sectAlign(s->sect.virt_size);
	int data_delta = fileAlign(virt_sz) - fileAlign(s->sect.virt_size);

	for (int k = 0; k < sections.size(); ++k) {
		Section* t = sections[k];
		if (t->sect.virt_addr > s->sect.virt_addr) {
			t->sect.virt_addr += virt_delta;
			if (!strcmp(t->sect.name, ".reloc")) {
				ddir[5].rva = t->sect.virt_addr;
			}
		}
		if (t->sect.data_addr > s->sect.data_addr) {
			t->sect.data_addr += data_delta;
		}
	}

	ddir[2].size = virt_sz;
	opts->image_size += virt_delta;

	s->sect.virt_size = virt_sz;
	s->sect.data_size = data_sz;

	delete[] s->data;
	s->data = new char[data_sz];
	closeRsrcDir(s, 0, rsrc_root);

	delete rsrc_root;
	rsrc_root = 0;
}

static Rsrc* findRsrc(int id, Rsrc* p)
{
	for (int k = 0; k < p->kids.size(); ++k) {
		if (p->kids[k]->id == id)
			return p->kids[k];
	}
	return 0;
}

static Rsrc* findRsrc(int type, int id, int lang)
{
	Rsrc* r = findRsrc(type, rsrc_root);
	if (!r)
		return 0;
	r = findRsrc(id, r);
	if (!r)
		return 0;
	return findRsrc(lang, r);
}

static void loadImage(std::istream& in)
{
	int k;

	//read stub
	in.seekg(0x3c);
	in.read((char*)&stub_sz, 4);
	stub_sz += 4;
	stub = new char[stub_sz];
	in.seekg(0);
	in.read(stub, stub_sz);

	//read head
	head    = new Head;
	head_sz = sizeof(Head);
	in.read((char*)head, head_sz);

	//read opts
	opts    = new Opts;
	opts_sz = sizeof(Opts);
	in.read((char*)opts, opts_sz);

	//read data dirs
	ddir_sz = opts->dir_entries * sizeof(DDir);
	ddir    = (DDir*)new char[ddir_sz];
	in.read((char*)ddir, ddir_sz);

	//read sects...
	for (k = 0; k < head->num_sects; ++k) {
		Section* s = new Section;
		in.read((char*)&s->sect, sizeof(Sect));
		sections.push_back(s);
	}

	for (k = 0; k < head->num_sects; ++k) {
		Section* s = sections[k];
		if (!s->sect.data_addr)
			continue;
		int data_sz = s->sect.data_size;
		s->data     = new char[data_sz]; //char[s->sect.virt_size];
		//memset( s->data,0,s->sect.virt_size );
		in.seekg(s->sect.data_addr);
		in.read(s->data, data_sz);
	}
}

static void saveImage(std::ostream& out)
{
	int k;

	out.write((char*)stub, stub_sz);
	out.write((char*)head, head_sz);
	out.write((char*)opts, opts_sz);
	out.write((char*)ddir, ddir_sz);

	for (k = 0; k < head->num_sects; ++k) {
		Section* s = sections[k];
		out.write((char*)&s->sect, sizeof(Sect));
	}

	for (k = 0; k < head->num_sects; ++k) {
		Section* s = sections[k];
		if (!s->sect.data_addr)
			continue;
		//assumes sect data is in order!!!!!
		while (out.tellp() < s->sect.data_addr)
			out.put((char)0xbb);
		out.seekp(s->sect.data_addr);
		out.write(s->data, s->sect.data_size);
	}
}

/********************** PUBLIC STUFF ***********************/

bool openImage(const char* img)
{
	img_file = img;

	std::fstream in(img_file, std::ios_base::binary | std::ios_base::in);
	loadImage(in);
	in.close();
	return true;
}

bool makeExe(int entry)
{
	if (!img_file)
		return false;

	head->chars |= 0x0002;  //executable
	head->chars &= ~0x2000; //not Dll
	opts->entry = entry;
	//	opts->image_base=0x400000;	//have to deal to fix-ups to do this properly.
	return true;
}

bool replaceRsrc(int type, int id, int lang, void* data, int data_sz)
{
	if (!img_file)
		return false;

	for (int k = 0; k < sections.size(); ++k) {
		Section* s = sections[k];
		if (strcmp(s->sect.name, ".rsrc"))
			continue;

		openRsrcTree(s);
		if (Rsrc* r = findRsrc(type, id, lang)) {
			delete[] r->data;
			r->data_sz = data_sz;
			r->data    = new char[data_sz];
			memcpy(r->data, data, data_sz);
			closeRsrcTree(s);
			return true;
		}
		closeRsrcTree(s);
	}
	return false;
}

void closeImage()
{
	if (!img_file)
		return;

	std::fstream out(img_file, std::ios_base::binary | std::ios_base::out | std::ios_base::trunc);
	saveImage(out);
	out.close();

	for (; sections.size(); sections.pop_back())
		delete sections.back();
	delete[] ddir;
	delete opts;
	delete head;
	delete[] stub;
	img_file = 0;
}

#endif