MakeROMFS-GUI/exefs_code.cc at master · MKGirlism/MakeROMFS-GUI · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
#include <cstdlib>
#include <cstring>
#include <cstdio>
#include "exefs_code.h"

#define die(msg) do { fputs(msg "\n\n", stderr); return 1; } while(0)
#define safe_call(a) do { int rc = a; if(rc != 0) return rc; } while(0)


ExefsCode::ExefsCode()
{
	InitCodeSegment(text_);
	InitCodeSegment(rodata_);
	InitCodeSegment(data_);
	InitCodeSegment(module_id_);
}

ExefsCode::~ExefsCode()
{
	FreeCodeSegment(text_);
	FreeCodeSegment(rodata_);
	FreeCodeSegment(data_);
	FreeCodeSegment(module_id_);
}

// internally generate code blob
// code blobs are normally page aligned, except in builtin sysmodules
int ExefsCode::CreateCodeBlob(const u8* elf, bool is_page_aligned)
{
	u8* text, *rodata, *data;

	safe_call(ParseElf(elf));

	if (is_page_aligned)
	{
		safe_call(code_blob_.alloc(PageToSize(text_.page_num + rodata_.page_num + data_.page_num)));

		text = (code_blob_.data() + 0);
		rodata = (code_blob_.data() + PageToSize(text_.page_num));
		data = (code_blob_.data() + PageToSize(text_.page_num + rodata_.page_num));
	}
	else
	{
		safe_call(code_blob_.alloc(text_.file_size + rodata_.file_size + data_.file_size));

		text = (code_blob_.data() + 0);
		rodata = (code_blob_.data() + text_.file_size);
		data = (code_blob_.data() + text_.file_size + rodata_.file_size);
	}

	memcpy(text, text_.data, text_.file_size);
	memcpy(rodata, rodata_.data, rodata_.file_size);
	memcpy(data, data_.data, data_.file_size);

	return 0;
}

int ExefsCode::ParseElf(const u8* elf)
{
	const Elf32_Ehdr* ehdr = (const Elf32_Ehdr*)elf;

	if (memcmp(ehdr->e_ident, ELF_MAGIC, 4) != 0) die("[ERROR] Not a valid ELF");

	if (ehdr->e_ident[EI_CLASS] != 1 || \
		ehdr->e_ident[EI_DATA] != ELFDATA2LSB || \
		le_hword(ehdr->e_type) != ET_EXEC || \
		le_hword(ehdr->e_machine) != ET_ARM)
	{
		die("[ERROR] Unsupported ELF");
	}

	const Elf32_Phdr* phdr = (const Elf32_Phdr*)(elf + le_word(ehdr->e_phoff));

	for (u16 i = 0; i < le_hword(ehdr->e_phnum); i++)
	{
		if (le_word(phdr[i].p_type) != PT_LOAD) continue;

		switch ((le_word(phdr[i].p_flags) & ~PF_CTRSDK))
		{
			// text
			case (PF_R | PF_X) :
			{
				CreateCodeSegment(text_, phdr[i], elf);
				break;
			}
			// rodata
			case (PF_R) :
			{
				// CTRSDK ELFs have ModuleId segments at the end
				if (i == le_hword(ehdr->e_phnum) - 1)
				{
					CreateCodeSegment(module_id_, phdr[i], elf);
				}
				else
				{
					CreateCodeSegment(rodata_, phdr[i], elf);
				}
				break;
			}
			// data
			case (PF_R | PF_W) :
			{
				CreateCodeSegment(data_, phdr[i], elf);
				break;
			}
		}
	}

	if (!text_.file_size) die("[ERROR] Failed to locate Text ELF Segment");
	if (!data_.file_size) die("[ERROR] Failed to locate Data ELF Segment");

	return 0;
}

void ExefsCode::InitCodeSegment(struct sCodeSegment& segment)
{
	segment.data = NULL;
	segment.address = 0;
	segment.memory_size = 0;
	segment.file_size = 0;
	segment.page_num = 0;
}


void ExefsCode::FreeCodeSegment(struct sCodeSegment& segment)
{
	if (segment.data != NULL)
	{
		free(segment.data);
	}

	InitCodeSegment(segment);
}

void ExefsCode::CreateCodeSegment(struct sCodeSegment& segment, const Elf32_Phdr& phdr, const u8* elf)
{
	FreeCodeSegment(segment);

	segment.address = le_word(phdr.p_vaddr);
	segment.file_size = le_word(phdr.p_filesz);
	segment.memory_size = le_word(phdr.p_memsz);

	segment.page_num = SizeToPage(segment.file_size);
	segment.data = (u8*)malloc(segment.file_size);
	if (segment.data == NULL)
	{
		InitCodeSegment(segment);
		return; // error maybe?
	}

	memcpy(segment.data, elf + le_word(phdr.p_offset), segment.file_size);
}