/**

 * $Id$

 *

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

 * whole procedure of manually 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 <glib/gstrfuncs.h>

#include <elf.h>

#include "mem.h"

#include "bootstrap.h"

#include "dreamcast.h"

#include "config.h"

#include "loader.h"

#include "drivers/cdrom/cdrom.h"

#include "drivers/cdrom/isofs.h"

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

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

char *file_loader_extensions[][2] = { 

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

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

        { NULL, NULL } };

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

typedef enum {

    FILE_ERROR,

    FILE_BINARY,

    FILE_ELF,

    FILE_ISO,

    FILE_DISC,

    FILE_ZIP,

    FILE_SAVE_STATE,

} lxdream_file_type_t;

static lxdream_file_type_t file_magic( const gchar *filename, int fd, ERROR *err )

{

    char buf[32];

    /* begin magic */

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

        SET_ERROR( err, errno, "Unable to read from file '%s'", filename );

        return FILE_ERROR;

    }

    lseek( fd, 0, SEEK_SET );

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

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

        return FILE_ELF;

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

        return FILE_ZIP;

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

        return FILE_SAVE_STATE;

    } else if( lseek( fd, 32768, SEEK_SET ) == 32768 &&

            read( fd, buf, 8 ) == 8 &&

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

        lseek( fd, 0, SEEK_SET );

        return FILE_ISO;

    }

    lseek( fd, 0, SEEK_SET );

    return FILE_BINARY;

}

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 */

                WARN( "ISO images not supported yet" );

            }

        }

    } 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 )

{

    gchar *bootstrap_file = lxdream_get_global_config_path_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_ENTRY_ADDR );

            g_free(bootstrap_file);

            return;

        }

    }

    dreamcast_program_loaded( filename, pc );

    g_free(bootstrap_file);

}    

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 is_sh4_elf( Elf32_Ehdr *head )

{

    return ( 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 );

}

gboolean is_arm_elf( Elf32_Ehdr *head )

{

    return ( 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_ARM &&

            head->e_version == 1 );

}

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( !is_sh4_elf(&head) ) {

        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;

}

/**

 * Create a new CDROM disc containing a single 1ST_READ.BIN.

 * @param type The disc type - must be CDROM_DISC_GDROM or CDROM_DISC_XA

 * @param bin The binary data (takes ownership)

 * @param bin_size

 */

cdrom_disc_t cdrom_disc_new_wrapped_binary( cdrom_disc_type_t type, const gchar *filename, unsigned char *bin, size_t bin_size,

                                            ERROR *err )

{

    IsoImage *iso = NULL;

    unsigned char *data = bin;

    cdrom_lba_t start_lba = 45000; /* GDROM_START */

    char bootstrap[32768];

    /* 1. Load in the bootstrap */

    gchar *bootstrap_file = lxdream_get_global_config_path_value(CONFIG_BOOTSTRAP);

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

        g_free(data);

        SET_ERROR( err, ENOENT, "Unable to create CD image: bootstrap file is not configured" );

        return NULL;

    }

    FILE *f = fopen( bootstrap_file, "ro" );

    if( f == NULL ) {

        g_free(data);

        SET_ERROR( err, errno, "Unable to create CD image: bootstrap file '%s' could not be opened", bootstrap_file );

        return FALSE;

    }

    size_t len = fread( bootstrap, 1, 32768, f );

    fclose(f);

    if( len != 32768 ) {

        g_free(data);

        SET_ERROR( err, EINVAL, "Unable to create CD image: bootstrap file '%s' is invalid", bootstrap_file );

        return FALSE;

    }

    /* 2. Scramble the binary if necessary (and set type settings) */

    if( type != CDROM_DISC_GDROM ) {

        /* scramble the binary if we're going the MIL-CD route */

        unsigned char *scramblebin = g_malloc(bin_size);

        bootprogram_scramble( scramblebin, bin, bin_size );

        data = scramblebin;

        start_lba = 0x2DB6; /* CDROM_START (does it matter?) */

        g_free(bin);

    }

    /* 3. Frob the bootstrap data */

    dc_bootstrap_head_t boot_header = (dc_bootstrap_head_t)bootstrap;

    memcpy( boot_header->boot_file, "1ST_READ.BIN    ", 16 );

    char tmp[129];

    int name_len = snprintf( tmp, 129, "lxdream wrapped image: %s", filename );

    if( name_len < 128 )

        memset( tmp+name_len, ' ', 128-name_len );

    memcpy( boot_header->product_name, tmp, 128 );

//    bootstrap_update_crc(bootstrap);

    /* 4. Build the ISO image */

    int status = iso_image_new("autocd", &iso);

    if( status != 1 ) {

        g_free(data);

        return NULL;

    }

    IsoStream *stream;

    if( iso_memory_stream_new(data, bin_size, &stream) != 1 ) {

        g_free(data);

        iso_image_unref(iso);

        return NULL;

    }

    iso_tree_add_new_file(iso_image_get_root(iso), "1ST_READ.BIN", stream, NULL);

    sector_source_t track = iso_sector_source_new( iso, SECTOR_MODE2_FORM1, start_lba,

            bootstrap, err );

    if( track == NULL ) {

        iso_image_unref(iso);

        return NULL;

    }

    cdrom_disc_t disc = cdrom_disc_new_from_track( type, track, start_lba );

    iso_image_unref(iso);

    if( disc != NULL ) {

        disc->name = g_strdup(filename);

    }

    return disc;

}

cdrom_disc_t cdrom_wrap_elf_fd( cdrom_disc_type_t type, const gchar *filename, int fd, ERROR *err )

{

    Elf32_Ehdr head;

    int i;

    /* Check the file header is actually an SH4 binary */

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

        return FALSE;

    if( !is_sh4_elf(&head) ) {

        SET_ERROR( err, EINVAL, "File is not an SH4 ELF executable file" );

        return FALSE;

    }

    if( head.e_entry != BINARY_LOAD_ADDR ) {

        SET_ERROR( err, EINVAL, "SH4 Binary has incorrect entry point (should be %08X but is %08X)", BINARY_LOAD_ADDR, head.e_entry );

        return FALSE;

    }

    /* Load the program headers */

    Elf32_Phdr phdr[head.e_phnum];

    lseek( fd, head.e_phoff, SEEK_SET );

    if( read( fd, phdr, sizeof(phdr) ) != sizeof(phdr) ) {

        SET_ERROR( err, EINVAL, "File is not a valid executable file" );

        return FALSE;

    }

    sh4addr_t start = (sh4addr_t)-1, end=0;

    /* Scan program headers for memory range in use */

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

        if( phdr[i].p_type == PT_LOAD ) {

            if( phdr[i].p_vaddr < start )

                start = phdr[i].p_vaddr;

            if( phdr[i].p_vaddr + phdr[i].p_memsz > end )

                end = phdr[i].p_vaddr + phdr[i].p_memsz;

        }

    }

    if( start != BINARY_LOAD_ADDR ) {

        SET_ERROR( err, EINVAL, "SH4 Binary has incorrect load address (should be %08X but is %08X)", BINARY_LOAD_ADDR, start );

        return FALSE;

    }

    if( end >= 0x8D000000 ) {

        SET_ERROR( err, EINVAL, "SH4 binary is too large to fit in memory (end address is %08X)", end );

        return FALSE;

    }

    /* Load the program into memory */

    char *program = g_malloc0( end-start );

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

        if( phdr[i].p_type == PT_LOAD ) {

            lseek( fd, phdr[i].p_offset, SEEK_SET );

            uint32_t size = MIN( phdr[i].p_filesz, phdr[i].p_memsz);

            read( fd, program + phdr[i].p_vaddr, size );

        }

    }

    /* And finally pass it over to the disc wrapper */

    return cdrom_disc_new_wrapped_binary(type, filename, program, end-start, err );

}

cdrom_disc_t cdrom_wrap_magic( cdrom_disc_type_t type, const gchar *filename, ERROR *err )

{

    cdrom_disc_t disc;

    char *data;

    int len;

    struct stat st;

    int fd = open( filename, O_RDONLY );

    if( fd == -1 ) {

        SET_ERROR( err, errno, "Unable to open file '%s'", filename );

        return NULL;

    }

    lxdream_file_type_t filetype = file_magic( filename, fd, err );

    switch( filetype ) {

    case FILE_BINARY:

        fstat( fd, &st );

        data = g_malloc(st.st_size);

        len = read( fd, data, st.st_size );

        close(fd);

        if( len != st.st_size ) {

            SET_ERROR( err, errno, "Error reading binary file '%s'", filename );

            return NULL;

        }

        return cdrom_disc_new_wrapped_binary( type, filename, data, st.st_size, err );

    case FILE_ELF:

        disc = cdrom_wrap_elf_fd(type, filename, fd, err);

        close(fd);

        return disc;

    default:

        close(fd);

        SET_ERROR( err, EINVAL, "File '%s' cannot be wrapped (not a binary)", filename );

        return NULL;

    }

}