/**

  * $Id$

  *

  * 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 ) {

         /* 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;

 }