// Copyright 2014 Citra Emulator Project
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.
#include <algorithm>
#include <vector>
#include "core/file_sys/archive_romfs.h"
#include "core/loader/elf.h"
#include "core/loader/ncch.h"
#include "core/hle/service/fs/archive.h"
#include "core/mem_map.h"
#include "3dsx.h"
namespace Loader {
/**
* File layout:
* - File header
* - Code, rodata and data relocation table headers
* - Code segment
* - Rodata segment
* - Loadable (non-BSS) part of the data segment
* - Code relocation table
* - Rodata relocation table
* - Data relocation table
*
* Memory layout before relocations are applied:
* [0..codeSegSize) -> code segment
* [codeSegSize..rodataSegSize) -> rodata segment
* [rodataSegSize..dataSegSize) -> data segment
*
* Memory layout after relocations are applied: well, however the loader sets it up :)
* The entrypoint is always the start of the code segment.
* The BSS section must be cleared manually by the application.
*/
enum THREEDSX_Error {
ERROR_NONE = 0,
ERROR_READ = 1,
ERROR_FILE = 2,
ERROR_ALLOC = 3
};
static const u32 RELOCBUFSIZE = 512;
// File header
static const u32 THREEDSX_MAGIC = 0x58534433; // '3DSX'
#pragma pack(1)
struct THREEDSX_Header
{
u32 magic;
u16 header_size, reloc_hdr_size;
u32 format_ver;
u32 flags;
// Sizes of the code, rodata and data segments +
// size of the BSS section (uninitialized latter half of the data segment)
u32 code_seg_size, rodata_seg_size, data_seg_size, bss_size;
};
// Relocation header: all fields (even extra unknown fields) are guaranteed to be relocation counts.
struct THREEDSX_RelocHdr
{
// # of absolute relocations (that is, fix address to post-relocation memory layout)
u32 cross_segment_absolute;
// # of cross-segment relative relocations (that is, 32bit signed offsets that need to be patched)
u32 cross_segment_relative;
// more?
// Relocations are written in this order:
// - Absolute relocations
// - Relative relocations
};
// Relocation entry: from the current pointer, skip X words and patch Y words
struct THREEDSX_Reloc
{
u16 skip, patch;
};
#pragma pack()
struct THREEloadinfo
{
u8* seg_ptrs[3]; // code, rodata & data
u32 seg_addrs[3];
u32 seg_sizes[3];
};
static u32 TranslateAddr(u32 addr, THREEloadinfo *loadinfo, u32* offsets)
{
if (addr < offsets[0])
return loadinfo->seg_addrs[0] + addr;
if (addr < offsets[1])
return loadinfo->seg_addrs[1] + addr - offsets[0];
return loadinfo->seg_addrs[2] + addr - offsets[1];
}
static THREEDSX_Error Load3DSXFile(FileUtil::IOFile& file, u32 base_addr)
{
if (!file.IsOpen())
return ERROR_FILE;
THREEDSX_Header hdr;
if (file.ReadBytes(&hdr, sizeof(hdr)) != sizeof(hdr))
return ERROR_READ;
THREEloadinfo loadinfo;
//loadinfo segments must be a multiple of 0x1000
loadinfo.seg_sizes[0] = (hdr.code_seg_size + 0xFFF) &~0xFFF;
loadinfo.seg_sizes[1] = (hdr.rodata_seg_size + 0xFFF) &~0xFFF;
loadinfo.seg_sizes[2] = (hdr.data_seg_size + 0xFFF) &~0xFFF;
u32 offsets[2] = { loadinfo.seg_sizes[0], loadinfo.seg_sizes[0] + loadinfo.seg_sizes[1] };
u32 data_load_size = (hdr.data_seg_size - hdr.bss_size + 0xFFF) &~0xFFF;
u32 bss_load_size = loadinfo.seg_sizes[2] - data_load_size;
u32 n_reloc_tables = hdr.reloc_hdr_size / 4;
std::vector<u8> all_mem(loadinfo.seg_sizes[0] + loadinfo.seg_sizes[1] + loadinfo.seg_sizes[2] + 3 * n_reloc_tables);
loadinfo.seg_addrs[0] = base_addr;
loadinfo.seg_addrs[1] = loadinfo.seg_addrs[0] + loadinfo.seg_sizes[0];
loadinfo.seg_addrs[2] = loadinfo.seg_addrs[1] + loadinfo.seg_sizes[1];
loadinfo.seg_ptrs[0] = &all_mem[0];
loadinfo.seg_ptrs[1] = loadinfo.seg_ptrs[0] + loadinfo.seg_sizes[0];
loadinfo.seg_ptrs[2] = loadinfo.seg_ptrs[1] + loadinfo.seg_sizes[1];
// Skip header for future compatibility
file.Seek(hdr.header_size, SEEK_SET);
// Read the relocation headers
u32* relocs = (u32*)(loadinfo.seg_ptrs[2] + hdr.data_seg_size);
for (u32 current_segment = 0; current_segment < 3; current_segment++) {
if (file.ReadBytes(&relocs[current_segment*n_reloc_tables], n_reloc_tables * 4) != n_reloc_tables * 4)
return ERROR_READ;
}
// Read the segments
if (file.ReadBytes(loadinfo.seg_ptrs[0], hdr.code_seg_size) != hdr.code_seg_size)
return ERROR_READ;
if (file.ReadBytes(loadinfo.seg_ptrs[1], hdr.rodata_seg_size) != hdr.rodata_seg_size)
return ERROR_READ;
if (file.ReadBytes(loadinfo.seg_ptrs[2], hdr.data_seg_size - hdr.bss_size) != hdr.data_seg_size - hdr.bss_size)
return ERROR_READ;
// BSS clear
memset((char*)loadinfo.seg_ptrs[2] + hdr.data_seg_size - hdr.bss_size, 0, hdr.bss_size);
// Relocate the segments
for (u32 current_segment = 0; current_segment < 3; current_segment++) {
for (u32 current_segment_reloc_table = 0; current_segment_reloc_table < n_reloc_tables; current_segment_reloc_table++) {
u32 n_relocs = relocs[current_segment*n_reloc_tables + current_segment_reloc_table];
if (current_segment_reloc_table >= 2) {
// We are not using this table - ignore it because we don't know what it dose
file.Seek(n_relocs*sizeof(THREEDSX_Reloc), SEEK_CUR);
continue;
}
static THREEDSX_Reloc reloc_table[RELOCBUFSIZE];
u32* pos = (u32*)loadinfo.seg_ptrs[current_segment];
u32* end_pos = pos + (loadinfo.seg_sizes[current_segment] / 4);
while (n_relocs) {
u32 remaining = std::min(RELOCBUFSIZE, n_relocs);
n_relocs -= remaining;
if (file.ReadBytes(reloc_table, remaining*sizeof(THREEDSX_Reloc)) != remaining*sizeof(THREEDSX_Reloc))
return ERROR_READ;
for (u32 current_inprogress = 0; current_inprogress < remaining && pos < end_pos; current_inprogress++) {
LOG_TRACE(Loader, "(t=%d,skip=%u,patch=%u)\n",
current_segment_reloc_table, (u32)reloc_table[current_inprogress].skip, (u32)reloc_table[current_inprogress].patch);
pos += reloc_table[current_inprogress].skip;
s32 num_patches = reloc_table[current_inprogress].patch;
while (0 < num_patches && pos < end_pos) {
u32 in_addr = (char*)pos - (char*)&all_mem[0];
u32 addr = TranslateAddr(*pos, &loadinfo, offsets);
LOG_TRACE(Loader, "Patching %08X <-- rel(%08X,%d) (%08X)\n",
base_addr + in_addr, addr, current_segment_reloc_table, *pos);
switch (current_segment_reloc_table) {
case 0: *pos = (addr); break;
case 1: *pos = (addr - in_addr); break;
default: break; //this should never happen
}
pos++;
num_patches--;
}
}
}
}
}
// Write the data
memcpy(Memory::GetPointer(base_addr), &all_mem[0], loadinfo.seg_sizes[0] + loadinfo.seg_sizes[1] + loadinfo.seg_sizes[2]);
LOG_DEBUG(Loader, "CODE: %u pages\n", loadinfo.seg_sizes[0] / 0x1000);
LOG_DEBUG(Loader, "RODATA: %u pages\n", loadinfo.seg_sizes[1] / 0x1000);
LOG_DEBUG(Loader, "DATA: %u pages\n", data_load_size / 0x1000);
LOG_DEBUG(Loader, "BSS: %u pages\n", bss_load_size / 0x1000);
return ERROR_NONE;
}
ResultStatus AppLoader_THREEDSX::Load() {
if (is_loaded)
return ResultStatus::ErrorAlreadyLoaded;
if (!file->IsOpen())
return ResultStatus::Error;
Load3DSXFile(*file, 0x00100000);
Kernel::LoadExec(0x00100000);
is_loaded = true;
return ResultStatus::Success;
}
} // namespace Loader
