/* $Id$ */
/* Copyright (c) 2011 Pierre Pronchery <khorben@defora.org> */
/* This file is part of DeforaOS Devel asm */
/* 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, version 3 of the License.
 *
 * 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, see <http://www.gnu.org/licenses/>. */



#include <System.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <elf.h>
#include "Asm.h"

/* portability */
#define Elf64_Quarter		unsigned char
#ifndef EM_486
# define EM_486			6
#endif


/* ELF */
/* private */
/* types */
typedef struct _ElfArch
{
	char const * arch;
	unsigned char machine;
	unsigned char capacity;
	unsigned char endian;
} ElfArch;

typedef struct _ElfSectionValues
{
	char const * name;
	Elf32_Word type;	/* works for 64-bit too */
	Elf32_Word flags;
} ElfSectionValues;

typedef struct _ElfStrtab
{
	char * buf;
	size_t cnt;
} ElfStrtab;


/* prototypes */
static int _elf_error(FormatPlugin * format);

/* plug-in */
static int _elf_init(FormatPlugin * format, char const * arch);
static char const * _elf_detect(FormatPlugin * format);
static int _elf_decode(FormatPlugin * format);
static int _elf_decode32(FormatPlugin * format);
static int _elf_decode64(FormatPlugin * format);

/* ELF32 */
static int _init_32(FormatPlugin * format);
static int _exit_32(FormatPlugin * format);
static int _section_32(FormatPlugin * format, char const * name);

/* ELF64 */
static int _init_64(FormatPlugin * format);
static int _exit_64(FormatPlugin * format);
static int _section_64(FormatPlugin * format, char const * name);

/* ElfStrtab */
static int _elfstrtab_set(FormatPlugin * format, ElfStrtab * strtab,
		char const * name);


/* variables */
static ElfArch elf_arch[] =
{
	{ "amd64",	EM_X86_64,	ELFCLASS64,	ELFDATA2LSB	},
	{ "i386",	EM_386,		ELFCLASS32,	ELFDATA2LSB	},
	{ "i486",	EM_386,		ELFCLASS32,	ELFDATA2LSB	},
	{ "i586",	EM_386,		ELFCLASS32,	ELFDATA2LSB	},
	{ "i686",	EM_386,		ELFCLASS32,	ELFDATA2LSB	},
	{ "sparc",	EM_SPARC,	ELFCLASS32,	ELFDATA2MSB	},
	{ "sparc64",	EM_SPARCV9,	ELFCLASS64,	ELFDATA2MSB	},
	{ NULL,		'\0',		'\0',		'\0'		}
};
static ElfArch * ea;

static ElfSectionValues elf_section_values[] =
{
	{ ".bss",	SHT_NOBITS,	SHF_ALLOC | SHF_WRITE		},
	{ ".comment",	SHT_PROGBITS,	0				},
	{ ".data",	SHT_PROGBITS,	SHF_ALLOC | SHF_WRITE		},
	{ ".data1",	SHT_PROGBITS,	SHF_ALLOC | SHF_WRITE		},
	{ ".debug",	SHT_PROGBITS,	0				},
	{ ".dynamic",	SHT_DYNAMIC,	0				},
	{ ".dynstr",	SHT_STRTAB,	SHF_ALLOC			},
	{ ".dynsym",	SHT_DYNSYM,	SHF_ALLOC			},
	{ ".fini",	SHT_PROGBITS,	SHF_ALLOC | SHF_EXECINSTR	},
	{ ".got",	SHT_PROGBITS,	0				},
	{ ".hash",	SHT_HASH,	SHF_ALLOC			},
	{ ".init",	SHT_PROGBITS,	SHF_ALLOC | SHF_EXECINSTR	},
	{ ".interp",	SHT_PROGBITS,	0				},
	{ ".line",	SHT_PROGBITS,	0				},
	{ ".note",	SHT_NOTE,	0				},
	{ ".plt",	SHT_PROGBITS,	0				},
	{ ".rodata",	SHT_PROGBITS,	SHF_ALLOC			},
	{ ".rodata1",	SHT_PROGBITS,	SHF_ALLOC			},
	{ ".shstrtab",	SHT_STRTAB,	0				},
	{ ".strtab",	SHT_STRTAB,	0				},
	{ ".symtab",	SHT_SYMTAB,	0				},
	{ ".text",	SHT_PROGBITS,	SHF_ALLOC | SHF_EXECINSTR	},
	{ NULL,		0,		0				}
};

static ElfStrtab shstrtab = { NULL, 0 };	/* section string table */


/* public */
/* variables */
/* format_plugin */
FormatPlugin format_plugin =
{
	NULL,
	"elf",
	ELFMAG,
	SELFMAG,
	_elf_init,
	NULL,
	NULL,
	NULL,
	_elf_detect,
	_elf_decode,
	NULL
};


/* private */
/* functions */
/* elf_error */
static int _elf_error(FormatPlugin * format)
{
	return -error_set_code(1, "%s: %s", format->helper->get_filename(
				format->helper->format), strerror(errno));
}


/* elf_init */
static ElfArch * _init_arch(char const * arch);

static int _elf_init(FormatPlugin * format, char const * arch)
{
	if((ea = _init_arch(arch)) == NULL)
		return 1;
	if(ea->capacity == ELFCLASS32)
	{
		if(_init_32(format) != 0)
			return 1;
		format->exit = _exit_32;
		format->section = _section_32;
	}
	else if(ea->capacity == ELFCLASS64)
	{
		if(_init_64(format) != 0)
			return 1;
		format->exit = _exit_64;
		format->section = _section_64;
	}
	else
		return 1;
	return 0;
}

static ElfArch * _init_arch(char const * arch)
{
	ElfArch * ea;

	for(ea = elf_arch; ea->arch != NULL; ea++)
		if(strcmp(ea->arch, arch) == 0)
			return ea;
	error_set_code(1, "%s: %s", arch, "Unsupported ELF architecture");
	return NULL;
}


/* elf_detect */
static char const * _detect_32(FormatPlugin * format, Elf32_Ehdr * ehdr);
static char const * _detect_64(FormatPlugin * format, Elf64_Ehdr * ehdr);

static char const * _elf_detect(FormatPlugin * format)
{
	FormatPluginHelper * helper = format->helper;
	union
	{
		Elf32_Ehdr ehdr32;
		Elf64_Ehdr ehdr64;
	} ehdr;

	if(helper->seek(helper->format, 0, SEEK_SET) != 0)
		return NULL;
	if(helper->read(helper->format, &ehdr, sizeof(ehdr)) != sizeof(ehdr))
		return NULL;
	switch(ehdr.ehdr32.e_ident[EI_CLASS])
	{
		case ELFCLASS32:
			return _detect_32(format, &ehdr.ehdr32);
		case ELFCLASS64:
			return _detect_64(format, &ehdr.ehdr64);
	}
	error_set_code(1, "%s: %s 0x%x\n", helper->get_filename(helper->format),
			"Unsupported ELF class", ehdr.ehdr32.e_ident[EI_CLASS]);
	return NULL;
}

static char const * _detect_32(FormatPlugin * format, Elf32_Ehdr * ehdr)
{
	format->decode = _elf_decode32;
	switch(ehdr->e_machine)
	{
		case EM_386:
		case EM_486:
			return "i686";
		case EM_ALPHA:
			return "alpha";
		case EM_ARM:
			return "arm";
		case EM_MIPS:
			return "mips";
		case EM_SPARC:
			return "sparc";
	}
	format->decode = _elf_decode;
	error_set_code(1, "%s: %s 0x%x", "elf", "Unsupported ELF architecture",
			ehdr->e_machine);
	return NULL;
}

static char const * _detect_64(FormatPlugin * format, Elf64_Ehdr * ehdr)
{
	format->decode = _elf_decode64;
	switch(ehdr->e_machine)
	{
		case EM_SPARC:
		case EM_SPARCV9:
			return "sparc64";
		case EM_X86_64:
			return "amd64";
	}
	format->decode = _elf_decode;
	error_set_code(1, "%s: %s 0x%x", "elf", "Unsupported ELF architecture",
			ehdr->e_machine);
	return NULL;
}


/* elf_decode */
static int _elf_decode(FormatPlugin * format)
{
	if(_elf_detect(format) == NULL)
		return -1;
	return format->decode(format);
}


/* elf_decode32 */
static int _decode32_shdr(FormatPlugin * format, Elf32_Ehdr * ehdr,
		Elf32_Shdr ** shdr);
static int _decode32_addr(FormatPlugin * format, Elf32_Ehdr * ehdr,
		Elf32_Addr * addr);
static int _decode32_strtab(FormatPlugin * format, Elf32_Shdr * shdr,
		size_t shdr_cnt, uint16_t ndx, char ** strtab,
		size_t * strtab_cnt);

static int _elf_decode32(FormatPlugin * format)
{
	FormatPluginHelper * helper = format->helper;
	Elf32_Ehdr ehdr;
	Elf32_Shdr * shdr = NULL;
	Elf32_Addr base = 0x0;
	char * shstrtab = NULL;
	size_t shstrtab_cnt = 0;
	size_t i;

#ifdef DEBUG
	fprintf(stderr, "DEBUG: %s() \"%s\"\n", __func__,
			format->helper->filename);
#endif
	if(helper->seek(helper->format, 0, SEEK_SET) != 0
			|| helper->read(helper->format, &ehdr, sizeof(ehdr))
			!= sizeof(ehdr))
		return -1;
	if(_decode32_shdr(format, &ehdr, &shdr) != 0)
		return -1;
	if(_decode32_addr(format, &ehdr, &base) != 0
			|| _decode32_strtab(format, shdr, ehdr.e_shnum,
				ehdr.e_shstrndx, &shstrtab, &shstrtab_cnt)
			!= 0)
	{
		free(shdr);
		return -1;
	}
	for(i = 0; i < ehdr.e_shnum; i++)
	{
		if(shdr[i].sh_name >= shstrtab_cnt)
			continue;
		if(shdr[i].sh_type == SHT_PROGBITS
				&& shdr[i].sh_flags & SHF_EXECINSTR)
			helper->decode(helper->format,
					&shstrtab[shdr[i].sh_name],
					shdr[i].sh_offset, shdr[i].sh_size,
					base);
	}
	free(shstrtab);
	free(shdr);
	return 0;
}

static int _decode32_shdr(FormatPlugin * format, Elf32_Ehdr * ehdr,
		Elf32_Shdr ** shdr)
{
	FormatPluginHelper * helper = format->helper;
	ssize_t size;

	if(ehdr->e_shentsize == 0)
	{
		*shdr = NULL;
		return 0;
	}
	if(ehdr->e_shentsize != sizeof(**shdr))
		return -error_set_code(1, "%s: %s",
				helper->get_filename(helper->format),
				"Invalid section header size");
	if(helper->seek(helper->format, ehdr->e_shoff, SEEK_SET) < 0)
		return -1;
	size = sizeof(**shdr) * ehdr->e_shnum;
	if((*shdr = malloc(size)) == NULL)
		return -_elf_error(format);
	if(helper->read(helper->format, *shdr, size) != size)
	{
		free(*shdr);
		return -1;
	}
	return 0;
}

static int _decode32_addr(FormatPlugin * format, Elf32_Ehdr * ehdr,
		Elf32_Addr * addr)
{
	FormatPluginHelper * helper = format->helper;
	Elf32_Half i;
	Elf32_Phdr phdr;

	if(helper->seek(helper->format, ehdr->e_phoff, SEEK_SET) < 0)
		return -1;
	for(i = 0; i < ehdr->e_phnum; i++)
		if(helper->read(helper->format, &phdr, sizeof(phdr))
				!= sizeof(phdr))
			return -1;
		else if(phdr.p_type == PT_LOAD && phdr.p_flags & (PF_R | PF_X))
		{
			*addr = phdr.p_vaddr;
			return 0;
		}
	*addr = 0x0;
	return 0;
}

static int _decode32_strtab(FormatPlugin * format, Elf32_Shdr * shdr,
		size_t shdr_cnt, uint16_t ndx, char ** strtab,
		size_t * strtab_cnt)
{
	FormatPluginHelper * helper = format->helper;

	if(ndx >= shdr_cnt)
		return -error_set_code(1, "%s: %s",
				helper->get_filename(helper->format),
				"Unable to read the string table");
	shdr = &shdr[ndx];
	if(helper->seek(helper->format, shdr->sh_offset, SEEK_SET) < 0)
		return -1;
	if((*strtab = malloc(shdr->sh_size)) == NULL)
		return -_elf_error(format);
	if(helper->read(helper->format, *strtab, shdr->sh_size)
			!= shdr->sh_size)
	{
		free(*strtab);
		return -1;
	}
	*strtab_cnt = shdr->sh_size;
	return 0;
}


/* elf_decode64 */
static int _decode64_shdr(FormatPlugin * format, Elf64_Ehdr * ehdr,
		Elf64_Shdr ** shdr);
static int _decode64_addr(FormatPlugin * format, Elf64_Ehdr * ehdr,
		Elf64_Addr * addr);
static int _decode64_strtab(FormatPlugin * format, Elf64_Shdr * shdr,
		size_t shdr_cnt, uint16_t ndx, char ** strtab,
		size_t * strtab_cnt);

static int _elf_decode64(FormatPlugin * format)
{
	FormatPluginHelper * helper = format->helper;
	Elf64_Ehdr ehdr;
	Elf64_Shdr * shdr = NULL;
	Elf64_Addr base = 0x0;
	char * shstrtab = NULL;
	size_t shstrtab_cnt = 0;
	size_t i;

#ifdef DEBUG
	fprintf(stderr, "DEBUG: %s() \"%s\"\n", __func__,
			helper->get_filename(helper->format));
#endif
	if(helper->seek(helper->format, 0, SEEK_SET) != 0
			|| helper->read(helper->format, &ehdr, sizeof(ehdr))
			!= sizeof(ehdr))
		return -1;
	if(_decode64_shdr(format, &ehdr, &shdr) != 0)
		return -1;
	if(_decode64_addr(format, &ehdr, &base) != 0
			|| _decode64_strtab(format, shdr, ehdr.e_shnum,
				ehdr.e_shstrndx, &shstrtab, &shstrtab_cnt)
			!= 0)
	{
		free(shdr);
		return -1;
	}
	for(i = 0; i < ehdr.e_shnum; i++)
	{
		if(shdr[i].sh_name >= shstrtab_cnt)
			continue;
		if(shdr[i].sh_type == SHT_PROGBITS
				&& shdr[i].sh_flags & SHF_EXECINSTR)
			helper->decode(helper->format,
					&shstrtab[shdr[i].sh_name],
					shdr[i].sh_offset, shdr[i].sh_size,
					base);
	}
	free(shstrtab);
	free(shdr);
	return 0;
}

static int _decode64_shdr(FormatPlugin * format, Elf64_Ehdr * ehdr,
		Elf64_Shdr ** shdr)
{
	FormatPluginHelper * helper = format->helper;
	ssize_t size;

	if(ehdr->e_shentsize == 0)
	{
		*shdr = NULL;
		return 0;
	}
	if(ehdr->e_shentsize != sizeof(**shdr))
		return -error_set_code(1, "%s: %s",
				helper->get_filename(helper->format),
				"Invalid section header size");
	if(helper->seek(helper->format, ehdr->e_shoff, SEEK_SET) < 0)
		return -1;
	size = sizeof(**shdr) * ehdr->e_shnum;
	if((*shdr = malloc(size)) == NULL)
		return -_elf_error(format);
	if(helper->read(helper->format, *shdr, size) != size)
	{
		free(*shdr);
		return -1;
	}
	return 0;
}

static int _decode64_addr(FormatPlugin * format, Elf64_Ehdr * ehdr,
		Elf64_Addr * addr)
{
	FormatPluginHelper * helper = format->helper;
	Elf64_Quarter i;
	Elf64_Phdr phdr;

	if(helper->seek(helper->format, ehdr->e_phoff, SEEK_SET) < 0)
		return -1;
	for(i = 0; i < ehdr->e_phnum; i++)
		if(helper->read(helper->format, &phdr, sizeof(phdr))
				!= sizeof(phdr))
			return -1;
		else if(phdr.p_type == PT_LOAD && phdr.p_flags & (PF_R | PF_X))
		{
			*addr = phdr.p_vaddr;
			return 0;
		}
	*addr = 0x0;
	return 0;
}

static int _decode64_strtab(FormatPlugin * format, Elf64_Shdr * shdr,
		size_t shdr_cnt, uint16_t ndx, char ** strtab,
		size_t * strtab_cnt)
{
	FormatPluginHelper * helper = format->helper;
	ssize_t size;

	if(ndx >= shdr_cnt)
		return -error_set_code(1, "%s: %s",
				helper->get_filename(helper->format),
				"Unable to read the string table");
	shdr = &shdr[ndx];
	if(helper->seek(helper->format, shdr->sh_offset, SEEK_SET) < 0)
		return -1;
	size = sizeof(**strtab) * shdr->sh_size;
	if((*strtab = malloc(size)) == NULL)
		return -_elf_error(format);
	if(helper->read(helper->format, *strtab, size) != size)
	{
		free(*strtab);
		return -1;
	}
	*strtab_cnt = shdr->sh_size;
	return 0;
}


/* section_values */
static ElfSectionValues * _section_values(char const * name)
{
	ElfSectionValues * esv;
	int cmp;

	for(esv = elf_section_values; esv->name != NULL; esv++)
		if((cmp = strcmp(esv->name, name)) == 0)
			return esv;
		else if(cmp > 0)
			break;
	for(; esv->name != NULL; esv++);
	return esv;
}


/* ELF32 */
/* variables */
static Elf32_Shdr * es32 = NULL;
static int es32_cnt = 0;


/* init_32 */
static int _init_32(FormatPlugin * format)
{
	FormatPluginHelper * helper = format->helper;
	Elf32_Ehdr hdr;

	memset(&hdr, 0, sizeof(hdr));
	memcpy(&hdr.e_ident, ELFMAG, SELFMAG);
	hdr.e_ident[EI_CLASS] = ELFCLASS32;
	hdr.e_ident[EI_DATA] = ea->endian;
	hdr.e_ident[EI_VERSION] = EV_CURRENT;
	if(ea->endian == ELFDATA2MSB)
	{
		hdr.e_type = _htob16(ET_REL);
		hdr.e_machine = _htob16(ea->machine);
		hdr.e_version = _htob32(EV_CURRENT);
		hdr.e_ehsize = _htob16(sizeof(hdr));
		hdr.e_shentsize = _htob16(sizeof(Elf32_Shdr));
		hdr.e_shstrndx = _htob16(SHN_UNDEF);
	}
	else
	{
		hdr.e_type = _htol16(ET_REL);
		hdr.e_machine = _htol16(ea->machine);
		hdr.e_version = _htol32(EV_CURRENT);
		hdr.e_ehsize = _htol16(sizeof(hdr));
		hdr.e_shentsize = _htol16(sizeof(Elf32_Shdr));
		hdr.e_shstrndx = _htol16(SHN_UNDEF);
	}
	if(helper->write(helper->format, &hdr, sizeof(hdr)) != sizeof(hdr))
		return _elf_error(format);
	return 0;
}


/* exit_32 */
static int _exit_32_phdr(FormatPlugin * format, Elf32_Off offset);
static int _exit_32_shdr(FormatPlugin * format, Elf32_Off offset);

static int _exit_32(FormatPlugin * format)
{
	int ret = 0;
	FormatPluginHelper * helper = format->helper;
	long offset;

	if(_section_32(format, ".shstrtab") != 0)
		ret = -1;
	else if(helper->write(helper->format, shstrtab.buf, shstrtab.cnt)
			!= (ssize_t)shstrtab.cnt)
		ret = -1;
	else if((offset = helper->seek(helper->format, 0, SEEK_CUR)) < 0)
		ret = -1;
	else if(_exit_32_phdr(format, offset) != 0
			|| _exit_32_shdr(format, offset) != 0)
		ret = -1;
	free(es32);
	es32 = NULL;
	es32_cnt = 0;
	free(shstrtab.buf);
	shstrtab.buf = NULL;
	shstrtab.cnt = 0;
	return ret;
}

static int _exit_32_phdr(FormatPlugin * format, Elf32_Off offset)
{
	FormatPluginHelper * helper = format->helper;
	Elf32_Ehdr hdr;

	if(es32_cnt == 0)
		return 0;
	if(helper->seek(helper->format, 0, SEEK_SET) != 0)
		return -1;
	if(helper->read(helper->format, &hdr, sizeof(hdr)) != sizeof(hdr))
		return _elf_error(format);
	if(ea->endian == ELFDATA2MSB)
	{
		hdr.e_shoff = _htob32(offset);
		hdr.e_shnum = _htob16(es32_cnt + 1);
		hdr.e_shstrndx = _htob16(es32_cnt);
	}
	else
	{
		hdr.e_shoff = _htol32(offset);
		hdr.e_shnum = _htol16(es32_cnt + 1);
		hdr.e_shstrndx = _htol16(es32_cnt);
	}
	if(helper->seek(helper->format, 0, SEEK_SET) != 0)
		return -1;
	if(helper->write(helper->format, &hdr, sizeof(hdr)) != sizeof(hdr))
		return -1;
	return 0;
}

static int _exit_32_shdr(FormatPlugin * format, Elf32_Off offset)
{
	FormatPluginHelper * helper = format->helper;
	Elf32_Shdr hdr;
	int i;

	if(helper->seek(helper->format, 0, SEEK_END) < 0)
		return _elf_error(format);
	memset(&hdr, 0, sizeof(hdr));
	if(ea->endian == ELFDATA2MSB)
	{
		hdr.sh_type = _htob32(SHT_NULL);
		hdr.sh_link = _htob32(SHN_UNDEF);
	}
	else
	{
		hdr.sh_type = _htol32(SHT_NULL);
		hdr.sh_link = _htol32(SHN_UNDEF);
	}
	if(helper->write(helper->format, &hdr, sizeof(hdr)) != sizeof(hdr))
		return -1;
	for(i = 0; i < es32_cnt; i++)
	{
		if(i + 1 == es32_cnt)
			es32[i].sh_size = offset - es32[i].sh_offset;
		else
			es32[i].sh_size = es32[i + 1].sh_offset
				- es32[i].sh_offset;
		es32[i].sh_size = ea->endian == ELFDATA2MSB
			? _htob32(es32[i].sh_size) : _htol32(es32[i].sh_size);
		if(helper->write(helper->format, &es32[i], sizeof(Elf32_Shdr))
				!= sizeof(Elf32_Shdr))
			return -1;
	}
	return 0;
}


/* section_32 */
static int _section_32(FormatPlugin * format, char const * name)
{
	FormatPluginHelper * helper = format->helper;
	int ss;
	Elf32_Shdr * p;
	ElfSectionValues * esv;
	long offset;

	if((ss = _elfstrtab_set(format, &shstrtab, name)) < 0)
		return -1;
	if((p = realloc(es32, sizeof(*es32) * (es32_cnt + 1))) == NULL)
		return _elf_error(format);
	es32 = p;
	p = &es32[es32_cnt++];
	memset(p, 0, sizeof(*p));
	esv = _section_values(name);
	p->sh_name = ss;
	p->sh_type = esv->type;
	p->sh_flags = esv->flags;
	if((offset = helper->seek(helper->format, 0, SEEK_CUR)) < 0)
		return -1;
	p->sh_offset = offset;
	p->sh_link = SHN_UNDEF; /* FIXME */
	return 0;
}


/* ELF64 */
/* variables */
static Elf64_Shdr * es64 = NULL;
static int es64_cnt = 0;


/* init_64 */
static int _init_64(FormatPlugin * format)
{
	FormatPluginHelper * helper = format->helper;
	Elf64_Ehdr hdr;

	memset(&hdr, 0, sizeof(hdr));
	memcpy(&hdr.e_ident, ELFMAG, SELFMAG);
	hdr.e_ident[EI_CLASS] = ELFCLASS64;
	hdr.e_ident[EI_DATA] = ea->endian;
	hdr.e_ident[EI_VERSION] = EV_CURRENT;
	if(ea->endian == ELFDATA2MSB)
	{
		hdr.e_type = _htob16(ET_REL);
		hdr.e_machine = _htob16(ea->machine);
		hdr.e_version = _htob32(EV_CURRENT);
		hdr.e_ehsize = _htob16(sizeof(hdr));
		hdr.e_shentsize = _htob16(sizeof(Elf64_Shdr));
	}
	else
	{
		hdr.e_type = _htol16(ET_REL);
		hdr.e_machine = _htol16(ea->machine);
		hdr.e_version = _htol32(EV_CURRENT);
		hdr.e_ehsize = _htol16(sizeof(hdr));
		hdr.e_shentsize = _htol16(sizeof(Elf64_Shdr));
	}
	hdr.e_shstrndx = SHN_UNDEF;
	if(helper->write(helper->format, &hdr, sizeof(hdr)) != sizeof(hdr))
		return -1;
	return 0;
}


/* exit_64 */
static int _exit_64_phdr(FormatPlugin * format, Elf64_Off offset);
static int _exit_64_shdr(FormatPlugin * format, Elf64_Off offset);

static int _exit_64(FormatPlugin * format)
{
	int ret = 0;
	FormatPluginHelper * helper = format->helper;
	long offset;

	if(_section_64(format, ".shstrtab") != 0)
		ret = 1;
	else if(helper->write(helper->format, shstrtab.buf, shstrtab.cnt)
				!= (ssize_t)shstrtab.cnt)
		ret = -1;
	else if((offset = helper->seek(helper->format, 0, SEEK_CUR)) < 0)
		ret = -1;
	else if(_exit_64_phdr(format, offset) != 0
			|| _exit_64_shdr(format, offset) != 0)
		ret = 1;
	free(es64);
	es64 = NULL;
	es64_cnt = 0;
	free(shstrtab.buf);
	shstrtab.buf = NULL;
	shstrtab.cnt = 0;
	return ret;
}

static int _exit_64_phdr(FormatPlugin * format, Elf64_Off offset)
{
	FormatPluginHelper * helper = format->helper;
	Elf64_Ehdr hdr;

	if(es64_cnt == 0)
		return 0;
	if(helper->seek(helper->format, 0, SEEK_SET) != 0)
		return -1;
	if(helper->read(helper->format, &hdr, sizeof(hdr)) != sizeof(hdr))
		return -1;
	if(ea->endian == ELFDATA2MSB)
	{
		hdr.e_shoff = _htob64(offset);
		hdr.e_shnum = _htob16(es64_cnt);
		hdr.e_shstrndx = _htob16(es64_cnt - 1);
	}
	else
	{
		hdr.e_shoff = _htol64(offset);
		hdr.e_shnum = _htol16(es64_cnt);
		hdr.e_shstrndx = _htol16(es64_cnt - 1);
	}
	if(helper->seek(helper->format, 0, SEEK_SET) != 0)
		return -1;
	if(helper->write(helper->format, &hdr, sizeof(hdr)) != sizeof(hdr))
		return -1;
	return 0;
}

static int _exit_64_shdr(FormatPlugin * format, Elf64_Off offset)
{
	FormatPluginHelper * helper = format->helper;
	int i;

	if(helper->seek(helper->format, 0, SEEK_END) < 0)
		return -1;
	for(i = 0; i < es64_cnt; i++)
	{
		if(i + 1 == es64_cnt)
			es64[i].sh_size = offset - es64[i].sh_offset;
		else
			es64[i].sh_size = es64[i+1].sh_offset
				- es64[i].sh_offset;
		es64[i].sh_size = ea->endian == ELFDATA2MSB
			? _htob64(es64[i].sh_size) : _htol64(es64[i].sh_size);
		if(helper->write(helper->format, &es64[i], sizeof(Elf64_Shdr))
				!= sizeof(Elf64_Shdr))
			return -1;
	}
	return 0;
}


/* section_64 */
static int _section_64(FormatPlugin * format, char const * name)
{
	FormatPluginHelper * helper = format->helper;
	int ss;
	Elf64_Shdr * p;
	ElfSectionValues * esv;
	long offset;

	if((ss = _elfstrtab_set(format, &shstrtab, name)) < 0)
		return 1;
	if((p = realloc(es64, sizeof(*es64) * (es64_cnt + 1))) == NULL)
		return _elf_error(format);
	es64 = p;
	p = &es64[es64_cnt++];
	memset(p, 0, sizeof(*p));
	esv = _section_values(name);
	p->sh_name = ss;
	p->sh_type = esv->type;
	p->sh_flags = esv->flags;
	if((offset = helper->seek(helper->format, 0, SEEK_CUR)) < 0)
		return -1;
	p->sh_offset = offset;
	p->sh_link = SHN_UNDEF; /* FIXME */
	return 0;
}


/* ElfStrtab */
/* private */
/* functions */
/* elfstrtab_get */
static int _elfstrtab_set(FormatPlugin * format, ElfStrtab * strtab,
		char const * name)
{
	size_t len;
	size_t cnt;
	char * p;

	if((len = strlen(name)) == 0 && strtab->cnt != 0)
		return 0;
	if((cnt = strtab->cnt) == 0)
		cnt++;
	if((p = realloc(strtab->buf, sizeof(char) * (cnt + len + 1))) == NULL)
		return -_elf_error(format);
	else if(strtab->buf == NULL)
		p[0] = '\0';
	strtab->buf = p;
	if(len == 0)
	{
		strtab->cnt = cnt;
		return 0;
	}
	strtab->cnt = cnt + len + 1;
	memcpy(&strtab->buf[cnt], name, len + 1);
	return cnt;
}