/* $Id: cramfs.c,v 1.1 2009/02/21 21:25:19 khorben Exp $ */
/* Copyright (c) 2008 khorben of UberWall */
/* 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 2 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, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */



#include <stdint.h>
#include <string.h>
#include "plugin.h"


/* cramfs */
/* public */
/* types */
struct cramfs
{
	uint32_t magic;
	uint32_t size;
	uint32_t flags;
	uint32_t padding;
	char signature[16];
	uint32_t crc;
	uint32_t edition;
	uint32_t blocks;
	uint32_t files;
	char name[16];
};


/* constants */
#define CRAMFS_MAGIC		0x28cd3d45
#define CRAMFS_SIGNATURE	"Compressed ROMFS"

/* flags */
#define CRAMFS_FLAG_FSID_VERSION_2	0x00000001	/* fsid version #2 */
#define CRAMFS_FLAG_SORTED_DIRS		0x00000002	/* sorted dirs */
#define CRAMFS_FLAG_HOLES		0x00000100	/* support for holes */
#define CRAMFS_FLAG_WRONG_SIGNATURE	0x00000200	/* reserved */
#define CRAMFS_FLAG_SHIFTED_ROOT_OFFSET	0x00000400	/* shifted root fs */

#define CRAMFS_SUPPORTED_FLAGS	( 0x000000ff \
		| CRAMFS_FLAG_HOLES \
		| CRAMFS_FLAG_WRONG_SIGNATURE \
		| CRAMFS_FLAG_SHIFTED_ROOT_OFFSET )


/* variables */
/* magic */
static unsigned char sig1[] = "\x45\x3d\xcd\x28";
static unsigned char sig2[] = "\x28\xcd\x3d\x45";
static unsigned char sig3[] = CRAMFS_SIGNATURE;

static PluginMagic cramfs_magic[] =
{
	{ sizeof(struct cramfs),	0,	sig1,	sizeof(sig1)-1	},
	{ sizeof(struct cramfs),	0,	sig2,	sizeof(sig2)-1	},
	{ sizeof(struct cramfs),	16,	sig3,	sizeof(sig3)-1	},
	{ 0,				0,	NULL,	0		}
};


/* functions */
static int cramfs_callback(PluginHelper * ph, int signature, FILE * fp);


/* plugin */
Plugin plugin =
{
	PT_ARCHIVE | PT_COMPRESSION,
	"CRAMFS",
	cramfs_magic,
	cramfs_callback
};


/* private */
/* functions */
/* cramfs_callback */
static void _callback_endian_little(struct cramfs * hdr);
static void _callback_endian_big(struct cramfs * hdr);
static int _callback_flags(PluginHelper * ph, uint32_t flags);

static int cramfs_callback(PluginHelper * ph, int signature, FILE * fp)
{
	int score = 0;
	struct cramfs buf;
	char name[sizeof(buf.name) + 1];

	if(fread(&buf, sizeof(buf), 1, fp) != 1)
		return -1;
	if(signature == 0 || htol32(buf.magic) == CRAMFS_MAGIC)
	{
		score+=100;
		ph->printf(ph, "%s", "little endian");
		_callback_endian_little(&buf);
	}
	else if(signature == 1 || htob32(buf.magic) == CRAMFS_MAGIC)
	{
		score+=100;
		ph->printf(ph, "%s", "big endian");
		_callback_endian_big(&buf);
	}
	if(strncmp(buf.signature, CRAMFS_SIGNATURE, sizeof(buf.signature) - 1)
			== 0)
		score+=100;
	strncpy(name, buf.name, sizeof(buf.name));
	name[sizeof(buf.name)] = '\0';
	ph->printf(ph, "%s%u", ", size ", buf.size);
	score+=_callback_flags(ph, buf.flags);
	ph->printf(ph, "%s%u%s%u%s%s%s", ", ", buf.blocks, " blocks, ",
			buf.files, " files, name \"", name, "\"\n");
	return score / 3;
}

/* one of these two helpers is eventually useless */
static void _callback_endian_little(struct cramfs * hdr)
{
	hdr->magic = htol32(hdr->magic);
	hdr->size = htol32(hdr->size);
	hdr->flags = htol32(hdr->flags);
	hdr->padding = htol32(hdr->padding);
	hdr->crc = htol32(hdr->crc);
	hdr->edition = htol32(hdr->edition);
	hdr->blocks = htol32(hdr->blocks);
	hdr->files = htol32(hdr->files);
}

static void _callback_endian_big(struct cramfs * hdr)
{
	hdr->magic = htob32(hdr->magic);
	hdr->size = htob32(hdr->size);
	hdr->flags = htob32(hdr->flags);
	hdr->padding = htob32(hdr->padding);
	hdr->crc = htob32(hdr->crc);
	hdr->edition = htob32(hdr->edition);
	hdr->blocks = htob32(hdr->blocks);
	hdr->files = htob32(hdr->files);
}

static int _callback_flags(PluginHelper * ph, uint32_t flags)
{
	char sep = ' ';

	if(flags & ~CRAMFS_SUPPORTED_FLAGS)
	{
		ph->printf(ph, "%s", ", invalid flags");
		return 0;
	}
	ph->printf(ph, "%s", ", flags");
	if(flags & CRAMFS_FLAG_FSID_VERSION_2)
	{
		ph->printf(ph, "%c%s", sep, "VERSION_2");
		sep = '|';
	}
	if(flags & CRAMFS_FLAG_SORTED_DIRS)
	{
		ph->printf(ph, "%c%s", sep, "SORTED_DIRS");
		sep = '|';
	}
	if(flags & CRAMFS_FLAG_HOLES)
	{
		ph->printf(ph, "%c%s", sep, "HOLES");
		sep = '|';
	}
	if(flags & CRAMFS_FLAG_SHIFTED_ROOT_OFFSET)
	{
		ph->printf(ph, "%c%s", sep, "SHIFTED_ROOT_OFFSET");
		sep = '|';
	}
	if(sep == ' ')
		ph->printf(ph, "%s", " NONE");
	return 100;
}