code.c

#include "lib.h"
#include "elf.h"
#include "code.h"

const u32 CTR_PAGE_SIZE = 0x1000;
const u32 DEFAULT_STACK_SIZE = 0x4000; // 10KB

typedef struct code_segment
{
	u32 address;
	u32 memSize;
	u32 fileSize;
	u32 pageNum;
	const u8 *data;
} code_segment;

u32 SizeToPage(u32 memorySize)
{
	return align(memorySize, CTR_PAGE_SIZE) / CTR_PAGE_SIZE;
}

u32 PageToSize(u32 pageNum)
{
	return pageNum * CTR_PAGE_SIZE;
}

int ImportPlainRegionFromElf(elf_context *elf, ncch_settings *set)
{
	elf_segment segment = elf_GetSegments(elf)[elf_SegmentNum(elf) - 1];

	/* Check last segment
	If the last segment is RO segment, this must be an SDK .module_id segment */
	if (segment.flags != PF_RODATA) {
		/* not a RO segment */
		return 0;
	}

	if (segment.fileSize > 0) {
		/* Creating Output Buffer */
		set->sections.plainRegion.size = align(segment.fileSize, set->options.blockSize);
		set->sections.plainRegion.buffer = calloc(set->sections.plainRegion.size, 1);
		if (!set->sections.plainRegion.buffer) { fprintf(stderr, "[CODE ERROR] Not enough memory\n"); return MEM_ERROR; }

		/* Copy Plain Region */
		memcpy(set->sections.plainRegion.buffer, segment.ptr, segment.fileSize);
	}
	return 0;
}

void CreateCodeSegmentFromElf(code_segment *out, elf_context *elf, u64 segment_flags)
{
	u32 segmentNum = elf_SegmentNum(elf);
	const elf_segment *segments = elf_GetSegments(elf);

	/* Initialise struct data */
	out->address = 0;
	out->memSize = 0;
	out->pageNum = 0;
	out->fileSize = 0;
	out->data = NULL;

	/* Find segment */
	for (u16 i = 0; i < segmentNum; i++) {
		/*	Skip SDK ELF .module_id segment
			The last segment should always be data in valid ELFs, 
			unless this is an SDK ELF with .module_id segment */
		if (i == segmentNum-1 && segments[i].flags == PF_RODATA)
			continue;

		/* Found segment */
		if ((segments[i].flags & ~PF_CTRSDK) == segment_flags && segments[i].type == PT_LOAD) {
			out->address = segments[i].vAddr;
			out->memSize = segments[i].memSize;
			out->fileSize = segments[i].fileSize;
			out->pageNum = SizeToPage(out->fileSize);
			out->data = segments[i].ptr;
			break;
		}
	}
}

int CreateExeFsCode(elf_context *elf, ncch_settings *set)
{
	/* Getting Code Segments */
	code_segment text;
	code_segment rodata;
	code_segment rwdata;

	CreateCodeSegmentFromElf(&text, elf, PF_TEXT);
	CreateCodeSegmentFromElf(&rodata, elf, PF_RODATA);
	CreateCodeSegmentFromElf(&rwdata, elf, PF_DATA);

	/* Checking the existence of essential ELF Segments */
	if (!text.fileSize) return NOT_FIND_TEXT_SEGMENT;
	if (!rwdata.fileSize) return NOT_FIND_DATA_SEGMENT;

	/* Calculating BSS size */
	set->codeDetails.bssSize = rwdata.memSize - rwdata.fileSize;

	/* Allocating Buffer for ExeFs Code */
	bool noCodePadding = set->options.noCodePadding;
	u32 size;
	if (noCodePadding) {
		size = text.fileSize + rodata.fileSize + rwdata.fileSize;
	}
	else {
		size = PageToSize(text.pageNum + rodata.pageNum + rwdata.pageNum);
	}
	u8 *code = calloc(1, size);

	/* Writing Code into Buffer */
	u8 *textPos = code;
	u8 *rodataPos = (textPos + (noCodePadding ? text.fileSize : PageToSize(text.pageNum)));
	u8 *rwdataPos = (rodataPos + (noCodePadding ? rodata.fileSize : PageToSize(rodata.pageNum)));
	if (text.fileSize) memcpy(textPos, text.data, text.fileSize);
	if (rodata.fileSize) memcpy(rodataPos, rodata.data, rodata.fileSize);
	if (rwdata.fileSize) memcpy(rwdataPos, rwdata.data, rwdata.fileSize);

	set->exefsSections.code.size = size;
	set->exefsSections.code.buffer = code;

	/* Setting code_segment data and freeing original buffers */
	set->codeDetails.textAddress = text.address;
	set->codeDetails.textMaxPages = text.pageNum;
	set->codeDetails.textSize = text.fileSize;

	set->codeDetails.roAddress = rodata.address;
	set->codeDetails.roMaxPages = rodata.pageNum;
	set->codeDetails.roSize = rodata.fileSize;

	set->codeDetails.rwAddress = rwdata.address;
	set->codeDetails.rwMaxPages = rwdata.pageNum;
	set->codeDetails.rwSize = rwdata.fileSize;

	/*if (set->rsfSet->SystemControlInfo.StackSize)
		set->codeDetails.stackSize = strtoul(set->rsfSet->SystemControlInfo.StackSize, NULL, 0);
	else {
		set->codeDetails.stackSize = DEFAULT_STACK_SIZE;
		fprintf(stderr, "[CODE WARNING] \"SystemControlInfo/StackSize\" not specified, defaulting to 0x%x bytes\n", DEFAULT_STACK_SIZE);
	}*/

	/* Return */
	return 0;
}

/*
void PrintElfContext(elf_context *elf)
{
	printf("[ELF] Program Table Data\n");
	printf(" Offset: 0x%x\n", elf->programTableOffset);
	printf(" Size:   0x%x\n", elf->programTableEntrySize);
	printf(" Count:  0x%x\n", elf->programTableEntryCount);
	printf("[ELF] Section Table Data\n");
	printf(" Offset: 0x%x\n", elf->sectionTableOffset);
	printf(" Size:   0x%x\n", elf->sectionTableEntrySize);
	printf(" Count:  0x%x\n", elf->sectionTableEntryCount);
	printf(" Label index: 0x%x\n", elf->sectionHeaderNameEntryIndex);
	for (int i = 0; i < elf->activeSegments; i++) {
		printf(" Segment [%d][%s]\n", i, elf->segments[i].name);
		printf(" > Size(Memory):   0x%x\n", elf->segments[i].header->sizeInMemory);
		printf(" > Size(File):     0x%x\n", elf->segments[i].header->sizeInFile);
		printf(" > Address:        0x%x\n", elf->segments[i].vAddr);
		printf(" > Flags:          0x%x\n", elf->segments[i].header->flags);
		printf(" > Type:           0x%x\n", elf->segments[i].header->type);
		printf(" > Sections: %d\n", elf->segments[i].sectionNum);
		for (int j = 0; j < elf->segments[i].sectionNum; j++)
			printf("    > Section [%d][%s][0x%x][0x%x]\n", j, elf->segments[i].sections[j].name, elf->segments[i].sections[j].flags, elf->segments[i].sections[j].type);
	}
}
*/

int BuildExeFsCode(ncch_settings *set)
{
	int result = 0;
	/* Import ELF */
	u8 *elfFile = malloc(set->componentFilePtrs.elfSize);
	if (!elfFile) {
		fprintf(stderr, "[CODE ERROR] Not enough memory\n");
		return MEM_ERROR;
	}
	ReadFile64(elfFile, set->componentFilePtrs.elfSize, 0, set->componentFilePtrs.elf);

	/* Create ELF Context */
	elf_context elf;

	if ((result = elf_Init(&elf, elfFile))) goto finish;

	if ((result = ImportPlainRegionFromElf(&elf, set))) goto finish;
	if ((result = CreateExeFsCode(&elf, set))) goto finish;

finish:
	switch (result) {
	case (0) :
		break;
	case (NOT_ELF_FILE) :
		fprintf(stderr, "[CODE ERROR] Not ELF File\n");
		break;
	case (NOT_CTR_ARM_ELF) :
		fprintf(stderr, "[CODE ERROR] Not CTR ARM ELF\n");
		break;
	case (NON_EXECUTABLE_ELF) :
		fprintf(stderr, "[CODE ERROR] Not Executeable ELF\n");
		break;
	case (NOT_FIND_TEXT_SEGMENT) :
		fprintf(stderr, "[CODE ERROR] Failed to retrieve text sections from ELF\n");
		break;
	case (NOT_FIND_DATA_SEGMENT) :
		fprintf(stderr, "[CODE ERROR] Failed to retrieve data sections from ELF\n");
		break;
	default:
		fprintf(stderr, "[CODE ERROR] Failed to process ELF file (%d)\n", result);
	}
	
	elf_Free(&elf);
	free(elfFile);
	return result;
}