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/* ScummVM - Graphic Adventure Engine
*
* ScummVM is the legal property of its developers, whose names
* are too numerous to list here. Please refer to the COPYRIGHT
* file distributed with this source distribution.
*
* This program 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 2
* of the License, or (at your option) any later version.
* This program 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 this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
* $URL$
* $Id$
*
*/
#if defined(DYNAMIC_MODULES) // TODO: && defined ELF loader target
#include <string.h>
#include <stdarg.h>
#include <stdio.h>
#include <malloc.h> // for memalign() (Linux specific)
#include <unistd.h>
#include <sys/fcntl.h>
#include <sys/_default_fcntl.h> // FIXME: Why do we need this DevKitPro specific header?
#include "common/file.h"
#include "common/fs.h"
#include "elf-loader.h"
#ifdef __DS__
#include <nds.h>
#endif
#define __DEBUG_PLUGINS__
#ifdef __DEBUG_PLUGINS__
#define DBG(x,...) printf(x, ## __VA_ARGS__)
#else
#define DBG(x,...)
#endif
#define seterror(x,...) printf(x, ## __VA_ARGS__)
/**
* Flushes the data cache (Platform Specific).
*/
void flushDataCache() {
#ifdef __DS__
DC_FlushAll();
#endif
#ifdef __PLAYSTATION2__
FlushCache(0);
FlushCache(2);
#endif
}
// Expel the symbol table from memory
void DLObject::discard_symtab() {
free(_symtab);
free(_strtab);
_symtab = NULL;
_strtab = NULL;
_symbol_cnt = 0;
}
// Unload all objects from memory
void DLObject::unload() {
discard_symtab();
free(_segment);
_segment = NULL;
#ifdef MIPS_TARGET
if (_shortsSegment) {
ShortsMan.deleteSegment(_shortsSegment);
_shortsSegment = NULL;
}
#endif
}
bool DLObject::readElfHeader(Common::SeekableReadStream* DLFile, Elf32_Ehdr *ehdr) {
// Start reading the elf header. Check for errors
if (DLFile->read(ehdr, sizeof(*ehdr)) != sizeof(*ehdr) ||
memcmp(ehdr->e_ident, ELFMAG, SELFMAG) || // Check MAGIC
ehdr->e_type != ET_EXEC || // Check for executable
#ifdef ARM_TARGET
ehdr->e_machine != EM_ARM || // Check for ARM machine type
#endif
#ifdef MIPS_TARGET
ehdr->e_machine != EM_MIPS ||
#endif
ehdr->e_phentsize < sizeof(Elf32_Phdr) || // Check for size of program header
ehdr->e_shentsize != sizeof(Elf32_Shdr)) { // Check for size of section header
seterror("Invalid file type.");
return false;
}
DBG("phoff = %d, phentsz = %d, phnum = %d\n",
ehdr->e_phoff, ehdr->e_phentsize, ehdr->e_phnum);
return true;
}
bool DLObject::readProgramHeaders(Common::SeekableReadStream* DLFile, Elf32_Ehdr *ehdr, Elf32_Phdr *phdr, int num) {
// Read program header
if (DLFile->seek(ehdr->e_phoff + sizeof(*phdr)*num, SEEK_SET) < 0 ||
DLFile->read(phdr, sizeof(*phdr)) != sizeof(*phdr)) {
seterror("Program header load failed.");
return false;
}
// Check program header values
if (phdr->p_type != PT_LOAD || phdr->p_filesz > phdr->p_memsz) {
seterror("Invalid program header.");
return false;
}
DBG("offs = %x, filesz = %x, memsz = %x, align = %x\n",
phdr->p_offset, phdr->p_filesz, phdr->p_memsz, phdr->p_align);
return true;
}
bool DLObject::loadSegment(Common::SeekableReadStream* DLFile, Elf32_Phdr *phdr) {
char *baseAddress = 0;
#ifdef MIPS_TARGET
// We need to take account of non-allocated segment for shorts
if (phdr->p_flags & PF_X) { // This is a relocated segment
// Attempt to allocate memory for segment
int extra = phdr->p_vaddr % phdr->p_align; // Get extra length TODO: check logic here
DBG("extra mem is %x\n", extra);
if (phdr->p_align < 0x10000) phdr->p_align = 0x10000; // Fix for wrong alignment on e.g. AGI
if (!(_segment = (char *)memalign(phdr->p_align, phdr->p_memsz + extra))) {
seterror("Out of memory.\n");
return false;
}
DBG("allocated segment @ %p\n", _segment);
// Get offset to load segment into
baseAddress = (char *)_segment + phdr->p_vaddr;
_segmentSize = phdr->p_memsz + extra;
} else { // This is a shorts section.
_shortsSegment = ShortsMan.newSegment(phdr->p_memsz, (char *)phdr->p_vaddr);
baseAddress = _shortsSegment->getStart();
DBG("shorts segment @ %p to %p. Segment wants to be at %x. Offset=%x\n",
_shortsSegment->getStart(), _shortsSegment->getEnd(), phdr->p_vaddr, _shortsSegment->getOffset());
}
#else
// Attempt to allocate memory for segment
int extra = phdr->p_vaddr % phdr->p_align; // Get extra length TODO: check logic here
DBG("extra mem is %x\n", extra);
if (!(_segment = (char *)memalign(phdr->p_align, phdr->p_memsz + extra))) {
seterror("Out of memory.\n");
return false;
}
DBG("allocated segment @ %p\n", _segment);
// Get offset to load segment into
baseAddress = (char *)_segment + phdr->p_vaddr;
_segmentSize = phdr->p_memsz + extra;
#endif
// Set bss segment to 0 if necessary (assumes bss is at the end)
if (phdr->p_memsz > phdr->p_filesz) {
DBG("Setting %p to %p to 0 for bss\n", baseAddress + phdr->p_filesz, baseAddress + phdr->p_memsz);
memset(baseAddress + phdr->p_filesz, 0, phdr->p_memsz - phdr->p_filesz);
}
DBG("Reading the segment into memory\n");
// Read the segment into memory
if (DLFile->seek(phdr->p_offset, SEEK_SET) < 0 ||
DLFile->read(baseAddress, phdr->p_filesz) != (ssize_t)phdr->p_filesz) {
seterror("Segment load failed.");
return false;
}
DBG("Segment has been read into memory\n");
return true;
}
Elf32_Shdr * DLObject::loadSectionHeaders(Common::SeekableReadStream* DLFile, Elf32_Ehdr *ehdr) {
Elf32_Shdr *shdr = NULL;
// Allocate memory for section headers
if (!(shdr = (Elf32_Shdr *)malloc(ehdr->e_shnum * sizeof(*shdr)))) {
seterror("Out of memory.");
return NULL;
}
// Read from file into section headers
if (DLFile->seek(ehdr->e_shoff, SEEK_SET) < 0 ||
DLFile->read(shdr, ehdr->e_shnum * sizeof(*shdr)) !=
(ssize_t)(ehdr->e_shnum * sizeof(*shdr))) {
seterror("Section headers load failed.");
return NULL;
}
return shdr;
}
int DLObject::loadSymbolTable(Common::SeekableReadStream* DLFile, Elf32_Ehdr *ehdr, Elf32_Shdr *shdr) {
// Loop over sections, looking for symbol table linked to a string table
for (int i = 0; i < ehdr->e_shnum; i++) {
if (shdr[i].sh_type == SHT_SYMTAB &&
shdr[i].sh_entsize == sizeof(Elf32_Sym) &&
shdr[i].sh_link < ehdr->e_shnum &&
shdr[shdr[i].sh_link].sh_type == SHT_STRTAB &&
_symtab_sect < 0) {
_symtab_sect = i;
}
}
// Check for no symbol table
if (_symtab_sect < 0) {
seterror("No symbol table.");
return -1;
}
DBG("Symbol section at section %d, size %x\n", _symtab_sect, shdr[_symtab_sect].sh_size);
// Allocate memory for symbol table
if (!(_symtab = malloc(shdr[_symtab_sect].sh_size))) {
seterror("Out of memory.");
return -1;
}
// Read symbol table into memory
if (DLFile->seek(shdr[_symtab_sect].sh_offset, SEEK_SET) < 0 ||
DLFile->read(_symtab, shdr[_symtab_sect].sh_size) !=
(ssize_t)shdr[_symtab_sect].sh_size) {
seterror("Symbol table load failed.");
return -1;
}
// Set number of symbols
_symbol_cnt = shdr[_symtab_sect].sh_size / sizeof(Elf32_Sym);
DBG("Loaded %d symbols.\n", _symbol_cnt);
return _symtab_sect;
}
bool DLObject::loadStringTable(Common::SeekableReadStream* DLFile, Elf32_Shdr *shdr) {
int string_sect = shdr[_symtab_sect].sh_link;
// Allocate memory for string table
if (!(_strtab = (char *)malloc(shdr[string_sect].sh_size))) {
seterror("Out of memory.");
return false;
}
// Read string table into memory
if (DLFile->seek(shdr[string_sect].sh_offset, SEEK_SET) < 0 ||
DLFile->read(_strtab, shdr[string_sect].sh_size) !=
(ssize_t)shdr[string_sect].sh_size) {
seterror("Symbol table strings load failed.");
return false;
}
return true;
}
void DLObject::relocateSymbols(Elf32_Addr offset) {
int mainCount = 0;
int shortsCount= 0;
// Loop over symbols, add relocation offset
Elf32_Sym *s = (Elf32_Sym *)_symtab;
for (int c = _symbol_cnt; c--; s++) {
#ifdef MIPS_TARGET
// Make sure we don't relocate special valued symbols
if (s->st_shndx < SHN_LOPROC) {
if (!ShortsMan.inGeneralSegment((char *)s->st_value)) {
mainCount++;
s->st_value += offset;
if (s->st_value < (Elf32_Addr)_segment || s->st_value > (Elf32_Addr)_segment + _segmentSize)
seterror("Symbol out of bounds! st_value = %x\n", s->st_value);
} else { // shorts section
shortsCount++;
s->st_value += _shortsSegment->getOffset();
if (!_shortsSegment->inSegment((char *)s->st_value))
seterror("Symbol out of bounds! st_value = %x\n", s->st_value);
}
}
#else
// Make sure we don't relocate special valued symbols
if (s->st_shndx < SHN_LOPROC) {
mainCount++;
s->st_value += offset;
if (s->st_value < (Elf32_Addr)_segment || s->st_value > (Elf32_Addr)_segment + _segmentSize)
seterror("Symbol out of bounds! st_value = %x\n", s->st_value);
}
#endif
}
}
bool DLObject::load(Common::SeekableReadStream* DLFile) {
Elf32_Ehdr ehdr;
Elf32_Phdr phdr;
Elf32_Shdr *shdr;
bool ret = true;
if (readElfHeader(DLFile, &ehdr) == false) {
return false;
}
for (int i = 0; i < ehdr.e_phnum; i++) { //Load our segments
DBG("Loading segment %d\n", i);
if (readProgramHeaders(DLFile, &ehdr, &phdr, i) == false)
return false;
if (!loadSegment(DLFile, &phdr))
return false;
}
if ((shdr = loadSectionHeaders(DLFile, &ehdr)) == NULL)
ret = false;
if (ret && ((_symtab_sect = loadSymbolTable(DLFile, &ehdr, shdr)) < 0))
ret = false;
if (ret && (loadStringTable(DLFile, shdr) == false))
ret = false;
if (ret)
relocateSymbols((Elf32_Addr)_segment); // Offset by our segment allocated address
if (ret && (relocateRels(DLFile, &ehdr, shdr) == false))
ret = false;
free(shdr);
return ret;
}
bool DLObject::open(const char *path) {
Common::SeekableReadStream* DLFile;
void *ctors_start, *ctors_end;
DBG("open(\"%s\")\n", path);
Common::FSNode file(path);
if (!(DLFile = file.createReadStream())) {
seterror("%s not found.", path);
return false;
}
DBG("%s found!\n", path);
/*Try to load and relocate*/
if (!load(DLFile)) {
unload();
return false;
}
DBG("loaded!/n");
flushDataCache();
ctors_start = symbol("___plugin_ctors");
ctors_end = symbol("___plugin_ctors_end");
_dtors_start = symbol("___plugin_dtors");
_dtors_end = symbol("___plugin_dtors_end");
if (ctors_start == NULL || ctors_end == NULL || _dtors_start == NULL ||
_dtors_end == NULL) {
seterror("Missing ctors/dtors.");
_dtors_start = _dtors_end = NULL;
unload();
return false;
}
DBG(("Calling constructors.\n"));
for (void (**f)(void) = (void (**)(void))ctors_start; f != ctors_end; f++)
(**f)();
DBG(("%s opened ok.\n", path));
return true;
}
bool DLObject::close() {
if (_dtors_start != NULL && _dtors_end != NULL)
for (void (**f)(void) = (void (**)(void))_dtors_start; f != _dtors_end; f++)
(**f)();
_dtors_start = _dtors_end = NULL;
unload();
return true;
}
void *DLObject::symbol(const char *name) {
DBG(("symbol(\"%s\")\n", name));
if (_symtab == NULL || _strtab == NULL || _symbol_cnt < 1) {
seterror("No symbol table loaded.");
return NULL;
}
Elf32_Sym *s = (Elf32_Sym *)_symtab;
for (int c = _symbol_cnt; c--; s++)
// We can only import symbols that are global or weak in the plugin
if ((SYM_BIND(s->st_info) == STB_GLOBAL || SYM_BIND(s->st_info) == STB_WEAK) &&
!strcmp(name, _strtab + s->st_name)) {
// We found the symbol
DBG("=> %p\n", (void*)s->st_value);
return (void*)s->st_value;
}
// We didn't find the symbol
seterror("Symbol \"%s\" not found.", name);
return NULL;
}
#endif /* DYNAMIC_MODULES */
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