/**

 * $Id$

 *

 * File loading routines, mostly for loading demos without going through the

 * whole procedure of making a CD image for them.

 *

 * Copyright (c) 2005 Nathan Keynes.

 *

 * 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; either version 2 of the License, or

 * (at your option) any later version.

 *

 * 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.

 */

#include <unistd.h>

#include <stdio.h>

#include <string.h>

#include <fcntl.h>

#include <sys/stat.h>

#include <errno.h>

#include <stdint.h>

#include <elf.h>

#include "mem.h"

#include "bootstrap.h"

#include "dreamcast.h"

#include "config.h"

#include "loader.h"

char bootstrap_magic[32] = "SEGA SEGAKATANA SEGA ENTERPRISES";

char iso_magic[6] = "\001CD001";

char *file_loader_extensions[][2] = { 

        { "sbi", "Self Boot Inducer" },

        { "bin", "SH4 Bin file" },

        { NULL, NULL } };

#define BOOTSTRAP_LOAD_ADDR 0x8C008000

#define BOOTSTRAP_SIZE 32768

#define BINARY_LOAD_ADDR 0x8C010000

#define CDI_V2 0x80000004

#define CDI_V3 0x80000005

gboolean file_load_elf_fd( const gchar *filename, int fd );

gboolean file_load_magic( const gchar *filename )

{

    char buf[32];

    struct stat st;

    gboolean result = TRUE;

    int fd = open( filename, O_RDONLY );

    if( fd == -1 ) {

        return FALSE;

    }

    fstat( fd, &st );

    /* begin magic */

    if( read( fd, buf, 32 ) != 32 ) {

        ERROR( "Unable to read from file '%s'", filename );

        close(fd);

        return FALSE;

    }

    if( memcmp( buf, bootstrap_magic, 32 ) == 0 ) {

        /* we have a DC bootstrap */

        if( st.st_size == BOOTSTRAP_SIZE ) {

            sh4ptr_t load = mem_get_region( BOOTSTRAP_LOAD_ADDR );

            lseek( fd, 0, SEEK_SET );

            read( fd, load, BOOTSTRAP_SIZE );

            bootstrap_dump( load, TRUE );

            dreamcast_program_loaded( filename, BOOTSTRAP_LOAD_ADDR + 0x300 );

        } else {

            /* look for a valid ISO9660 header */

            lseek( fd, 32768, SEEK_SET );

            read( fd, buf, 8 );

            if( memcmp( buf, iso_magic, 6 ) == 0 ) {

                /* Alright, got it */

                INFO( "Loading ISO9660 filesystem from '%s'",

                        filename );

            }

        }

    } else if( memcmp( buf, "PK\x03\x04", 4 ) == 0 ) {

        /* ZIP file, aka SBI file */

        WARN( "SBI files not supported yet" );

        result = FALSE;

    } else if( memcmp( buf, DREAMCAST_SAVE_MAGIC, 16 ) == 0 ) {

        /* Save state */

        result = (dreamcast_load_state( filename )==0);

    } else if( buf[0] == 0x7F && buf[1] == 'E' && 

            buf[2] == 'L' && buf[3] == 'F' ) {

        /* ELF binary */

        lseek( fd, 0, SEEK_SET );

        result = file_load_elf_fd( filename, fd );

    } else {

        result = FALSE;

    }

    close(fd);

    return result;

}

void file_load_postload( const gchar *filename, int pc )

{

    const gchar *bootstrap_file = lxdream_get_config_value(CONFIG_BOOTSTRAP);

    if( bootstrap_file != NULL && bootstrap_file[0] != '\0' ) {

        /* Load in a bootstrap before the binary, to initialize everything

         * correctly

         */

        if( mem_load_block( bootstrap_file, BOOTSTRAP_LOAD_ADDR, BOOTSTRAP_SIZE ) == 0 ) {

            dreamcast_program_loaded( filename, BOOTSTRAP_LOAD_ADDR+0x300 );

            return;

        }

    }

    dreamcast_program_loaded( filename, pc );

}    

gboolean file_load_binary( const gchar *filename )

{

    /* Load the binary itself */

    if(  mem_load_block( filename, BINARY_LOAD_ADDR, -1 ) == 0 ) {

        file_load_postload( filename, BINARY_LOAD_ADDR );

        return TRUE;

    } else {

        return FALSE;

    }

}

gboolean file_load_elf_fd( const gchar *filename, int fd ) 

{

    Elf32_Ehdr head;

    Elf32_Phdr phdr;

    int i;

    if( read( fd, &head, sizeof(head) ) != sizeof(head) )

        return FALSE;

    if( head.e_ident[EI_CLASS] != ELFCLASS32 ||

            head.e_ident[EI_DATA] != ELFDATA2LSB ||

            head.e_ident[EI_VERSION] != 1 ||

            head.e_type != ET_EXEC ||

            head.e_machine != EM_SH ||

            head.e_version != 1 ) {

        ERROR( "File is not an SH4 ELF executable file" );

        return FALSE;

    }

    /* Program headers */

    for( i=0; i<head.e_phnum; i++ ) {

        lseek( fd, head.e_phoff + i*head.e_phentsize, SEEK_SET );

        read( fd, &phdr, sizeof(phdr) );

        if( phdr.p_type == PT_LOAD ) {

            lseek( fd, phdr.p_offset, SEEK_SET );

            sh4ptr_t target = mem_get_region( phdr.p_vaddr );

            read( fd, target, phdr.p_filesz );

            if( phdr.p_memsz > phdr.p_filesz ) {

                memset( target + phdr.p_filesz, 0, phdr.p_memsz - phdr.p_filesz );

            }

            INFO( "Loaded %d bytes to %08X", phdr.p_filesz, phdr.p_vaddr );

        }

    }

    file_load_postload( filename, head.e_entry );

    return TRUE;

}