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oot/tools/fado/lib/fairy/fairy.c
EllipticEllipsis 6fd0f3cff2
git subrepo pull --force tools/fado (#1138) 
subrepo:
  subdir:   "tools/fado"
  merged:   "a0fa82808"
upstream:
  origin:   "git@github.com:EllipticEllipsis/fado.git"
  branch:   "master"
  commit:   "a0fa82808"
git-subrepo:
  version:  "0.4.3"
  origin:   "https://github.com/ingydotnet/git-subrepo.git"
  commit:   "2f68596"
2022-02-11 15:09:27 -05:00

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/**
* Functions for working with N64 ELF files.
*/
/* Copyright (C) 2021 Elliptic Ellipsis */
/* SPDX-License-Identifier: AGPL-3.0-only */
#include "fairy.h"
#include <assert.h>
#include <stdarg.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "vc_vector/vc_vector.h"
#include "macros.h"
VerbosityLevel gVerbosity = VERBOSITY_NONE;
bool gUseElfAlignment = false;
int Fairy_DebugPrintf(const char* file, int line, const char* func, VerbosityLevel level, const char* fmt, ...) {
if (gVerbosity >= level) {
int ret = 0;
va_list args;
va_start(args, fmt);
if (gVerbosity >= VERBOSITY_DEBUG) {
ret += fprintf(stderr, "%s:%d:%s: ", file, line, func);
}
ret += vfprintf(stderr, fmt, args);
va_end(args);
return ret;
}
return 0;
}
/* Endian readers. MIPS is BE, so only need these */
static Elf32_Half Fairy_ReadHalf(const uint8_t* data) {
return data[0] << 8 | data[1] << 0;
}
static Elf32_Word Fairy_ReadWord(const uint8_t* data) {
return data[0] << 24 | data[1] << 16 | data[2] << 8 | data[3] << 0;
}
static bool Fairy_VerifyMagic(const uint8_t* data) {
return (data[0] == 0x7F && data[1] == 'E' && data[2] == 'L' && data[3] == 'F');
}
static uint16_t Fairy_Swap16(uint16_t x) {
return ((x & 0xFF) << 0x8) | ((x & 0xFF00) >> 0x8);
}
static uint32_t Fairy_Swap32(uint32_t x) {
return ((x & 0xFF) << 0x18) | ((x & 0xFF00) << 0x8) | ((x & 0xFF0000) >> 0x8) | ((x & 0xFF000000) >> 0x18);
}
/* Both GCC and Clang define these, so we can avoid an endian header altogether */
#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
#define REEND16(x) Fairy_Swap16(x)
#define REEND32(x) Fairy_Swap32(x)
#else
#define REEND16(x) (x)
#define REEND32(x) (x)
#endif
const char* Fairy_StringFromDefine(const FairyDefineString* dict, int define) {
size_t i;
for (i = 0; dict[i].string != NULL; i++) {
if (dict[i].define == define) {
return dict[i].string;
}
}
return NULL;
}
/**
* Returns true if the string 'initial' is contained in the string 'string'
* 'initial' must be null-terminated, 'string' ideally is.
*/
bool Fairy_StartsWith(const char* string, const char* initial) {
char s;
char i;
do {
s = *string++;
i = *initial++;
if (i == '\0') {
return true;
}
} while (s == i);
return false;
}
/* Reading functions */
/**
* Every reading function:
* - Returns the pointer to the struct
* - Takes the ouput struct or array as its first argument. This must be pre-allocated
* - Takes the input file as the second argument (At least until I am persuaded to read the whole file into RAM...)
* - The rest of the arguments are important information about the struct it is reading (offset and size, usually)
*/
FairyFileHeader* Fairy_ReadFileHeader(FairyFileHeader* header, FILE* file) {
fseek(file, 0, SEEK_SET);
assert(fread(header, 0x34, 1, file) != 0);
if (!Fairy_VerifyMagic(header->e_ident)) {
fprintf(stderr, "Not a valid ELF file.\n");
return NULL;
}
if (header->e_ident[EI_CLASS] != ELFCLASS32) {
fprintf(stderr, "Not a 32-bit ELF file.\n");
return NULL;
}
header->e_type = REEND16(header->e_type);
if (header->e_type != ET_REL) {
fprintf(stderr, "Not a relocatable object file.\n");
return NULL;
}
header->e_machine = REEND16(header->e_machine);
if (header->e_machine != EM_MIPS) {
fprintf(stderr, "Not a MIPS object file.\n");
return NULL;
}
header->e_version = REEND32(header->e_version);
header->e_entry = REEND32(header->e_entry);
header->e_phoff = REEND32(header->e_phoff);
header->e_shoff = REEND32(header->e_shoff);
header->e_flags = REEND32(header->e_flags);
header->e_ehsize = REEND16(header->e_ehsize);
header->e_phentsize = REEND16(header->e_phentsize);
header->e_phnum = REEND16(header->e_phnum);
header->e_shentsize = REEND16(header->e_shentsize);
header->e_shnum = REEND16(header->e_shnum);
header->e_shstrndx = REEND16(header->e_shstrndx);
return header;
}
/* tableOffset and number should be obtained from the file header */
FairySecHeader* Fairy_ReadSectionTable(FairySecHeader* sectionTable, FILE* file, size_t tableOffset, size_t number) {
size_t entrySize = sizeof(FairySecHeader);
size_t tableSize = number * entrySize;
fseek(file, tableOffset, SEEK_SET);
assert(fread(sectionTable, tableSize, 1, file) != 0);
/* Since the section table happens to only have entries of width 4, we can byteswap it by pretending it is a raw
* uint32_t array */
{
size_t i;
uint32_t* data = (uint32_t*)sectionTable;
for (i = 0; i < tableSize / sizeof(uint32_t); i++) {
data[i] = REEND32(data[i]);
}
}
return sectionTable;
}
FairySym* Fairy_ReadSymbolTable(FairySym* symbolTable, FILE* file, size_t tableOffset, size_t tableSize) {
size_t number = tableSize / sizeof(FairySym);
fseek(file, tableOffset, SEEK_SET);
assert(fread(symbolTable, tableSize, 1, file) != 0);
/* Reend the variables that are larger than bytes */
{
size_t i;
for (i = 0; i < number; i++) {
symbolTable[i].st_name = REEND32(symbolTable[i].st_name);
symbolTable[i].st_value = REEND32(symbolTable[i].st_value);
symbolTable[i].st_size = REEND32(symbolTable[i].st_size);
symbolTable[i].st_shndx = REEND16(symbolTable[i].st_shndx);
}
}
return symbolTable;
}
/* Can be used for both the section header string table and the strtab */
char* Fairy_ReadStringTable(char* stringTable, FILE* file, size_t tableOffset, size_t tableSize) {
fseek(file, tableOffset, SEEK_SET);
assert(fread(stringTable, tableSize, 1, file) != 0);
return stringTable;
}
/* offset and number are attained from the section table */
FairyRel* Fairy_ReadRelocs(FairyRel* relocTable, FILE* file, size_t offset, size_t size) {
fseek(file, offset, SEEK_SET);
assert(fread(relocTable, size, 1, file) != 0);
/* Reend the variables that are larger than bytes */
{
size_t i;
uint32_t* data = (uint32_t*)relocTable;
for (i = 0; i < size / sizeof(uint32_t); i++) {
data[i] = REEND32(data[i]);
}
}
return relocTable;
}
char* Fairy_GetSectionName(FairySecHeader* sectionTable, char* shstrtab, size_t index) {
return &shstrtab[sectionTable[index].sh_name];
}
/* Look up the index in the symbol table and return a pointer to the beginning of its string */
char* Fairy_GetSymbolName(FairySym* symtab, char* strtab, size_t index) {
return &strtab[symtab[index].st_name];
}
/* FairyFileInfo functions */
void Fairy_InitFile(FairyFileInfo* fileInfo, FILE* file) {
FairyFileHeader fileHeader;
FairySecHeader* sectionTable;
char* shstrtab;
int i;
assert(fileInfo != NULL);
assert(file != NULL);
fileInfo->progBitsSections = vc_vector_create(3, sizeof(Elf32_Section), NULL);
for (i = 0; i < 3; i++) {
fileInfo->progBitsSizes[i] = 0;
}
Fairy_ReadFileHeader(&fileHeader, file);
sectionTable = malloc(fileHeader.e_shnum * fileHeader.e_shentsize);
Fairy_ReadSectionTable(sectionTable, file, fileHeader.e_shoff, fileHeader.e_shnum);
shstrtab = malloc(sectionTable[fileHeader.e_shstrndx].sh_size * sizeof(char));
fseek(file, sectionTable[fileHeader.e_shstrndx].sh_offset, SEEK_SET);
assert(fread(shstrtab, sectionTable[fileHeader.e_shstrndx].sh_size, 1, file) != 0);
/* Search for the sections we need */
{
size_t currentIndex;
FairySecHeader currentSection;
for (currentIndex = 0; currentIndex < 3; currentIndex++) {
fileInfo->relocTablesInfo[currentIndex].sectionData = NULL;
}
for (currentIndex = 0; currentIndex < fileHeader.e_shnum; currentIndex++) {
currentSection = sectionTable[currentIndex];
switch (currentSection.sh_type) {
case SHT_PROGBITS:
assert(vc_vector_push_back(fileInfo->progBitsSections, &currentIndex));
{
FairySection sectionType = FAIRY_SECTION_OTHER;
const char* sectionName = &shstrtab[currentSection.sh_name + 1];
size_t alignedSize;
/* Ignore the leading "." */
if (strcmp(sectionName, "text") == 0) {
sectionType = FAIRY_SECTION_TEXT;
} else if (strcmp(sectionName, "data") == 0) {
sectionType = FAIRY_SECTION_DATA;
} else if (Fairy_StartsWith(sectionName, "rodata")) { /* May be several */
sectionType = FAIRY_SECTION_RODATA;
}
if (sectionType != FAIRY_SECTION_OTHER) {
if (gUseElfAlignment) {
/* Ensure the next file will start at its correct alignment */
fileInfo->progBitsSizes[sectionType] =
ALIGN(fileInfo->progBitsSizes[sectionType], currentSection.sh_addralign);
alignedSize = ALIGN(currentSection.sh_size, currentSection.sh_addralign);
FAIRY_DEBUG_PRINTF("%s section alignment: 0x%X\n", sectionName,
currentSection.sh_addralign);
FAIRY_DEBUG_PRINTF("%s section size before align: 0x%X\n", sectionName,
currentSection.sh_size);
FAIRY_DEBUG_PRINTF("%s section size after align: 0x%X\n", sectionName, alignedSize);
fileInfo->progBitsSizes[sectionType] += alignedSize;
} else {
fileInfo->progBitsSizes[sectionType] += ALIGN(currentSection.sh_size, 0x10);
}
FAIRY_DEBUG_PRINTF("%s section size: 0x%X\n", sectionName,
fileInfo->progBitsSizes[sectionType]);
}
}
break;
case SHT_SYMTAB:
if (strcmp(&shstrtab[currentSection.sh_name + 1], "symtab") == 0) {
fileInfo->symtabInfo.sectionSize = currentSection.sh_size;
fileInfo->symtabInfo.sectionData = malloc(currentSection.sh_size);
Fairy_ReadSymbolTable(fileInfo->symtabInfo.sectionData, file, currentSection.sh_offset,
currentSection.sh_size);
}
break;
case SHT_STRTAB:
if (strcmp(&shstrtab[currentSection.sh_name + 1], "strtab") == 0) {
FAIRY_DEBUG_PRINTF("%s", "strtab found\n");
fileInfo->strtab = malloc(currentSection.sh_size);
Fairy_ReadStringTable(fileInfo->strtab, file, currentSection.sh_offset, currentSection.sh_size);
}
break;
case SHT_REL:
/* This assumes only one reloc section of each name */
// TODO: is this a problem?
{
FairySection relocSection = FAIRY_SECTION_OTHER;
/* Ignore the first 5 chars, which will always be ".rel." */
if (strcmp(&shstrtab[currentSection.sh_name + 5], "text") == 0) {
relocSection = FAIRY_SECTION_TEXT;
FAIRY_DEBUG_PRINTF("%s", "Found rel.text section\n");
} else if (strcmp(&shstrtab[currentSection.sh_name + 5], "data") == 0) {
relocSection = FAIRY_SECTION_DATA;
FAIRY_DEBUG_PRINTF("%s", "Found rel.data section\n");
} else if (strcmp(&shstrtab[currentSection.sh_name + 5], "rodata") == 0) {
relocSection = FAIRY_SECTION_RODATA;
FAIRY_DEBUG_PRINTF("%s", "Found rel.rodata section\n");
} else {
break;
}
fileInfo->relocTablesInfo[relocSection].sectionSize = currentSection.sh_size;
fileInfo->relocTablesInfo[relocSection].sectionData = malloc(currentSection.sh_size);
Fairy_ReadRelocs(fileInfo->relocTablesInfo[relocSection].sectionData, file,
currentSection.sh_offset, currentSection.sh_size);
}
break;
default:
break;
}
}
}
free(sectionTable);
free(shstrtab);
}
void Fairy_DestroyFile(FairyFileInfo* fileInfo) {
size_t i;
for (i = 0; i < ARRAY_COUNTU(fileInfo->relocTablesInfo); i++) {
if (fileInfo->relocTablesInfo[i].sectionData != NULL) {
FAIRY_DEBUG_PRINTF("Freeing reloc section %zd data\n", i);
free(fileInfo->relocTablesInfo[i].sectionData);
}
}
vc_vector_release(fileInfo->progBitsSections);
FAIRY_DEBUG_PRINTF("%s", "Freeing symtab data\n");
free(fileInfo->symtabInfo.sectionData);
FAIRY_DEBUG_PRINTF("%s", "Freeing strtab data\n");
free(fileInfo->strtab);
}
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