Retro68/Elf2Mac/Object.cc

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/*
Copyright 2017 Wolfgang Thaller.
This file is part of Retro68.
Retro68 is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
Retro68 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 for more details.
You should have received a copy of the GNU General Public License
along with Retro68. If not, see <http://www.gnu.org/licenses/>.
*/
#include "Object.h"
#include "Symbol.h"
#include "Symtab.h"
#include "Section.h"
#include "SegmentMap.h"
#include "Reloc.h"
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#include <err.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <fstream>
#include <sstream>
#include <iostream>
#include <boost/algorithm/string/predicate.hpp>
#include <boost/lexical_cast.hpp>
#include "ResourceFork.h"
#include "BinaryIO.h"
#include "ResourceFile.h"
using std::string;
using std::shared_ptr;
using std::make_shared;
using std::ofstream;
using std::unordered_map;
using std::vector;
Object::~Object()
{
}
Object::Object(string input)
{
if(elf_version ( EV_CURRENT ) == EV_NONE)
errx(EXIT_FAILURE , "ELF library initialization failed: %s", elf_errmsg( -1));
int fd = open(input.c_str(), O_RDONLY, 0);
elf = elf_begin(fd, ELF_C_READ, NULL);
elf_getshdrstrndx(elf, &sectionHeaderStringTableIdx);
GElf_Ehdr ehdr;
gelf_getehdr(elf, &ehdr);
int idx;
idx = 1;
for(Elf_Scn *scn = NULL; (scn = elf_nextscn(elf, scn)) != NULL; idx++)
{
GElf_Shdr shdr;
gelf_getshdr(scn, &shdr);
std::string name = elf_strptr(elf, sectionHeaderStringTableIdx, shdr.sh_name);
if(shdr.sh_type == SHT_STRTAB)
{
if(name == ".strtab")
mainStringTableIdx = idx;
}
}
idx = 1;
for(Elf_Scn *scn = NULL; (scn = elf_nextscn(elf, scn)) != NULL; idx++)
{
GElf_Shdr shdr;
gelf_getshdr(scn, &shdr);
std::string name = elf_strptr(elf, sectionHeaderStringTableIdx, shdr.sh_name);
//std::cout << "section #" << idx << ": " << name << std::endl;
//std::cout << " =" << shdr.sh_addr << " + " << shdr.sh_size << std::endl;
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if(shdr.sh_type == SHT_SYMTAB
&& !symtab)
{
symtab.reset(new Symtab(*this, scn));
}
if(shdr.sh_type == SHT_RELA)
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{
if(boost::algorithm::starts_with(name,".rela."))
{
string progbitsName = name.substr(5);
assert(sections.find(progbitsName) != sections.end());
sections[progbitsName]->SetRela(scn);
}
}
if(shdr.sh_type == SHT_PROGBITS && (shdr.sh_flags & SHF_ALLOC))
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{
SectionKind kind = SectionKind::code;
if(name == ".data")
kind = SectionKind::data;
if(name == ".strippedmacsbugnames")
kind = SectionKind::undefined;
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auto section = make_shared<Section>(*this, name, idx, kind, scn);
sections[name] = sectionsByElfIndex[idx] = section;
if(kind == SectionKind::data)
dataSection = section;
else if(kind == SectionKind::code)
codeSections.push_back(section);
}
if(shdr.sh_type == SHT_NOBITS)
{
bssSection = sections[name] = sectionsByElfIndex[idx] =
make_shared<Section>(*this, name, idx, SectionKind::bss, scn);
}
}
std::sort(codeSections.begin(), codeSections.end(),
[](shared_ptr<Section> a, shared_ptr<Section> b) { return a->name < b->name; });
}
void Object::FlatCode(std::ostream& out)
{
for(auto sec : codeSections)
out << sec->GetData();
out << dataSection->GetData();
std::vector<RuntimeReloc> relocs;
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for(auto sec : codeSections)
{
auto tmp = sec->GetRelocations(false);
relocs.insert(relocs.end(), tmp.begin(), tmp.end());
}
{
auto tmp = dataSection->GetRelocations(false);
relocs.insert(relocs.end(), tmp.begin(), tmp.end());
}
out << SerializeRelocs(relocs);
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}
void Object::FlatCode(string fn)
{
ofstream out(fn);
FlatCode(out);
}
std::string fromhex(std::string hex)
{
std::string bin;
int nibble;
bool haveNibble = false;
for(std::string::iterator p = hex.begin(); p != hex.end(); ++p)
{
if(std::isspace(*p))
continue;
assert(isdigit(*p) || (tolower(*p) >= 'a' && tolower(*p) <= 'f'));
int digit;
if(isdigit(*p))
digit = *p - '0';
else
digit = tolower(*p) - 'a' + 0xA;
if(haveNibble)
{
bin += (char) ((nibble << 4) | digit);
haveNibble = false;
}
else
{
nibble = digit;
haveNibble = true;
}
}
return bin;
}
void Object::SingleSegmentApp(string output)
{
ResourceFile file(output);
Resources& rsrc = file.resources;
rsrc.addResource(Resource(ResType("CODE"), 0,
fromhex(
"00000028 00000000 00000008 00000020"
"0000 3F3C 0001 A9F0"
)
));
{
std::ostringstream code1;
word(code1, 0);
word(code1, 1);
FlatCode(code1);
rsrc.addResource(Resource(ResType("CODE"), 1,
code1.str()));
}
file.creator = ResType("????");
file.type = ResType("APPL");
file.write();
}
void Object::MultiSegmentApp(string output, SegmentMap& segmentMap)
{
ResourceFile file(output);
Resources& rsrc = file.resources;
for(auto namedSec : sections)
{
namedSec.second->ScanRelocs();
}
int jtEntryCount = 0;
unordered_map<int, vector<Symbol*>> jtEntries;
for(Symbol& sym : symtab->symbols)
{
if(sym.valid)
{
if(sym.referencedExternally && sym.sectionKind == SectionKind::code)
{
sym.needsJT = true;
sym.jtIndex = -1;
sym.section->jtEntries.push_back(&sym);
++jtEntryCount;
}
}
}
uint32_t data_and_bss_size = dataSection->shdr.sh_size + bssSection->shdr.sh_size;
{
std::ostringstream code0;
longword(code0, 0x20 + 8 * (jtEntryCount+2));
longword(code0, data_and_bss_size);
longword(code0, 8 * (jtEntryCount+2));
longword(code0, 0x20);
code0 << fromhex("0000 3F3C 0001 A9F0"); // jt entry for entrypoint
code0 << fromhex("0000 FFFF 0000 0000"); // 32-bit entries start from here
int jtIndex = 2;
int id = 1;
for(auto sec : codeSections)
{
sec->codeID = id;
sec->firstJTEntryIndex = jtIndex;
GElf_Shdr &shdr = sec->shdr;
for(Symbol* jtEntry : sec->jtEntries)
{
word(code0, id);
word(code0, 0xA9F0);
uint32_t offset = jtEntry->st_value - shdr.sh_addr;
if(id == 1)
offset += 4;
else
offset += 40;
longword(code0, offset);
jtEntry->jtIndex = jtIndex++;
//std::cout << "JT Entry " << jtEntry->jtIndex << ": " << jtEntry->name << std::endl;
}
id++;
}
std::cout << "CODE 0: " << code0.str().size() << " bytes\n";
std::cout << "above A5: " << 0x20 + 8 * (jtEntryCount+2) << " bytes\n";
std::cout << "below A5: " << data_and_bss_size << " bytes\n";
std::cout << ".data: " << dataSection->shdr.sh_size << " bytes at A5-"
<< std::hex << data_and_bss_size << std::dec << "\n";
std::cout << ".bss: " << bssSection->shdr.sh_size << " bytes at A5-"
<< std::hex << bssSection->shdr.sh_size << std::dec << "\n";
rsrc.addResource(Resource(ResType("CODE"), 0, code0.str()));
}
for(auto sec : codeSections)
{
int id = sec->codeID;
if(id == 1)
sec->outputBase = 4; // standard 'CODE' header
else
sec->outputBase = 40; // far-model 'CODE' header
string exceptionInfoMarker = "__EH_FRAME_BEGIN__";
if(id != 1)
exceptionInfoMarker += boost::lexical_cast<string>(id);
int exceptionInfoSym = symtab->FindSym(exceptionInfoMarker);
if(exceptionInfoSym != -1)
{
Symbol& s = symtab->GetSym(exceptionInfoSym);
sec->exceptionInfoStart = s.st_value;
int codeSize = sec->shdr.sh_size;
int exceptionSize = sec->shdr.sh_addr + codeSize - sec->exceptionInfoStart;
double percent = 100.0 * exceptionSize / codeSize;
std::cout << "CODE " << id << " has " << exceptionSize << " bytes of exception info (" << percent << "%)\n";
}
else
std::cout << "exception info marker not found: " << exceptionInfoMarker << std::endl;
}
dataSection->outputBase = -data_and_bss_size;
bssSection->outputBase = -bssSection->shdr.sh_size;
for(auto namedSec : sections)
{
namedSec.second->FixRelocs();
}
for(auto sec : codeSections)
{
int id = sec->codeID;
std::ostringstream code;
if(id == 1)
{
word(code, 0);
word(code, 1);
}
else
{
word(code, 0xFFFF);
word(code, 0);
longword(code, 0);
longword(code, 0);
longword(code, 8 * sec->firstJTEntryIndex );
longword(code, sec->jtEntries.size());
longword(code, 0); // reloc info for A5
longword(code, 0); // assumed address for A5
longword(code, 0); // reloc info for code
longword(code, 0); // assumed address for start of code resource
longword(code, 0);
}
code << sec->GetData();
std::cout << "CODE " << id << ": " << code.str().size() << " bytes\n";
if(code.str().size() == 80)
{
std::cout << "... empty. Skipping.\n";
continue;
}
string segmentName = segmentMap.GetSegmentName(id);
rsrc.addResource(Resource(ResType("CODE"), id,
code.str(),
segmentName));
rsrc.addResource(Resource(ResType("RELA"),id, SerializeRelocs(sec->GetRelocations(true))));
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}
rsrc.addResource(Resource(ResType("DATA"),0, dataSection->GetData()));
rsrc.addResource(Resource(ResType("RELA"),0, SerializeRelocs(dataSection->GetRelocations(true))));
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std::cout << "DATA 0: " << dataSection->shdr.sh_size << " bytes\n";
file.creator = ResType("????");
file.type = ResType("APPL");
file.write();
}