builtins.c

i386的bootloader源码grub

    default:
      errnum = ERR_NEED_LX_KERNEL;
      return 1;
    }

  return 0;
}

static struct builtin builtin_initrd =
{
  "initrd",
  initrd_func,
  BUILTIN_CMDLINE | BUILTIN_HELP_LIST,
  "initrd FILE [ARG ...]",
  "Load an initial ramdisk FILE for a Linux format boot image and set the"
  " appropriate parameters in the Linux setup area in memory."
};


/* install */
static int
install_func (char *arg, int flags)
{
  char *stage1_file, *dest_dev, *file, *addr;
  char *stage1_buffer = (char *) RAW_ADDR (0x100000);
  char *stage2_buffer = stage1_buffer + SECTOR_SIZE;
  char *old_sect = stage2_buffer + SECTOR_SIZE;
  char *stage2_first_buffer = old_sect + SECTOR_SIZE;
  char *stage2_second_buffer = stage2_first_buffer + SECTOR_SIZE;
  /* XXX: Probably SECTOR_SIZE is reasonable.  */
  char *config_filename = stage2_second_buffer + SECTOR_SIZE;
  char *dummy = config_filename + SECTOR_SIZE;
  int new_drive = GRUB_INVALID_DRIVE;
  int dest_drive, dest_partition, dest_sector;
  int src_drive, src_partition, src_part_start;
  int i;
  struct geometry dest_geom, src_geom;
  int saved_sector;
  int stage2_first_sector, stage2_second_sector;
  char *ptr;
  int installaddr, installlist;
  /* Point to the location of the name of a configuration file in Stage 2.  */
  char *config_file_location;
  /* If FILE is a Stage 1.5?  */
  int is_stage1_5 = 0;
  /* Must call grub_close?  */
  int is_open = 0;
  /* If LBA is forced?  */
  int is_force_lba = 0;
  /* Was the last sector full? */
  int last_length = SECTOR_SIZE;
  
#ifdef GRUB_UTIL
  /* If the Stage 2 is in a partition mounted by an OS, this will store
     the filename under the OS.  */
  char *stage2_os_file = 0;
#endif /* GRUB_UTIL */
  
  /* Save the first sector of Stage2 in STAGE2_SECT.  */
  static void disk_read_savesect_func (int sector, int offset, int length)
    {
      if (debug)
	printf ("[%d]", sector);

      /* ReiserFS has files which sometimes contain data not aligned
         on sector boundaries.  Returning an error is better than
         silently failing. */
      if (offset != 0 || length != SECTOR_SIZE)
	errnum = ERR_UNALIGNED;

      saved_sector = sector;
    }

  /* Write SECTOR to INSTALLLIST, and update INSTALLADDR and
     INSTALLSECT.  */
  static void disk_read_blocklist_func (int sector, int offset, int length)
    {
      if (debug)
	printf("[%d]", sector);

      if (offset != 0 || last_length != SECTOR_SIZE)
	{
	  /* We found a non-sector-aligned data block. */
	  errnum = ERR_UNALIGNED;
	  return;
	}

      last_length = length;

      if (*((unsigned long *) (installlist - 4))
	  + *((unsigned short *) installlist) != sector
	  || installlist == (int) stage2_first_buffer + SECTOR_SIZE + 4)
	{
	  installlist -= 8;

	  if (*((unsigned long *) (installlist - 8)))
	    errnum = ERR_WONT_FIT;
	  else
	    {
	      *((unsigned short *) (installlist + 2)) = (installaddr >> 4);
	      *((unsigned long *) (installlist - 4)) = sector;
	    }
	}

      *((unsigned short *) installlist) += 1;
      installaddr += 512;
    }

  /* First, check the GNU-style long option.  */
  while (1)
    {
      if (grub_memcmp ("--force-lba", arg, sizeof ("--force-lba") - 1) == 0)
	{
	  is_force_lba = 1;
	  arg = skip_to (0, arg);
	}
#ifdef GRUB_UTIL
      else if (grub_memcmp ("--stage2=", arg, sizeof ("--stage2=") - 1) == 0)
	{
	  stage2_os_file = arg + sizeof ("--stage2=") - 1;
	  arg = skip_to (0, arg);
	  nul_terminate (stage2_os_file);
	}
#endif /* GRUB_UTIL */
      else
	break;
    }
  
  stage1_file = arg;
  dest_dev = skip_to (0, stage1_file);
  if (*dest_dev == 'd')
    {
      new_drive = 0;
      dest_dev = skip_to (0, dest_dev);
    }
  file = skip_to (0, dest_dev);
  addr = skip_to (0, file);

  /* Get the installation address.  */
  if (! safe_parse_maxint (&addr, &installaddr))
    {
      /* ADDR is not specified.  */
      installaddr = 0;
      ptr = addr;
      errnum = 0;
    }
  else
    ptr = skip_to (0, addr);

#ifndef NO_DECOMPRESSION
  /* Do not decompress Stage 1 or Stage 2.  */
  no_decompression = 1;
#endif

  /* Read Stage 1.  */
  is_open = grub_open (stage1_file);
  if (! is_open
      || ! grub_read (stage1_buffer, SECTOR_SIZE) == SECTOR_SIZE)
    goto fail;

  /* Read the old sector from DEST_DEV.  */
  if (! set_device (dest_dev)
      || ! open_partition ()
      || ! devread (0, 0, SECTOR_SIZE, old_sect))
    goto fail;

  /* Store the information for the destination device.  */
  dest_drive = current_drive;
  dest_partition = current_partition;
  dest_geom = buf_geom;
  dest_sector = part_start;

  /* Copy the possible DOS BPB, 59 bytes at byte offset 3.  */
  grub_memmove (stage1_buffer + BOOTSEC_BPB_OFFSET,
		old_sect + BOOTSEC_BPB_OFFSET,
		BOOTSEC_BPB_LENGTH);

  /* If for a hard disk, copy the possible MBR/extended part table.  */
  if (dest_drive & 0x80)
    grub_memmove (stage1_buffer + STAGE1_WINDOWS_NT_MAGIC,
		  old_sect + STAGE1_WINDOWS_NT_MAGIC,
		  STAGE1_PARTEND - STAGE1_WINDOWS_NT_MAGIC);

  /* Check for the version and the signature of Stage 1.  */
  if (*((short *)(stage1_buffer + STAGE1_VER_MAJ_OFFS)) != COMPAT_VERSION
      || (*((unsigned short *) (stage1_buffer + BOOTSEC_SIG_OFFSET))
	  != BOOTSEC_SIGNATURE))
    {
      errnum = ERR_BAD_VERSION;
      goto fail;
    }

  /* This below is not true any longer. But should we leave this alone?  */
  
  /* If DEST_DRIVE is a floppy, Stage 2 must have the iteration probe
     routine.  */
  if (! (dest_drive & 0x80)
      && (*((unsigned char *) (stage1_buffer + BOOTSEC_PART_OFFSET)) == 0x80
	  || stage1_buffer[BOOTSEC_PART_OFFSET] == 0))
    {
      errnum = ERR_BAD_VERSION;
      goto fail;
    }

  grub_close ();
  
  /* Open Stage 2.  */
  is_open = grub_open (file);
  if (! is_open)
    goto fail;

  src_drive = current_drive;
  src_partition = current_partition;
  src_part_start = part_start;
  src_geom = buf_geom;
  
  if (! new_drive)
    new_drive = src_drive;
  else if (src_drive != dest_drive)
    grub_printf ("Warning: the option `d' was not used, but the Stage 1 will"
		 " be installed on a\ndifferent drive than the drive where"
		 " the Stage 2 resides.\n");

  /* Set the boot drive.  */
  *((unsigned char *) (stage1_buffer + STAGE1_BOOT_DRIVE)) = new_drive;

  /* Set the "force LBA" flag.  */
  *((unsigned char *) (stage1_buffer + STAGE1_FORCE_LBA)) = is_force_lba;

  /* Set the boot drive mask. This is a workaround for buggy BIOSes which
     don't pass boot drive correctly. Instead, they pass 0x00 even when
     booted from 0x80.  */
  *((unsigned char *) (stage1_buffer + STAGE1_BOOT_DRIVE_MASK))
    = (dest_drive & BIOS_FLAG_FIXED_DISK);
  
  /* Read the first sector of Stage 2.  */
  disk_read_hook = disk_read_savesect_func;
  if (grub_read (stage2_first_buffer, SECTOR_SIZE) != SECTOR_SIZE)
    goto fail;

  stage2_first_sector = saved_sector;
  
  /* Read the second sector of Stage 2.  */
  if (grub_read (stage2_second_buffer, SECTOR_SIZE) != SECTOR_SIZE)
    goto fail;

  stage2_second_sector = saved_sector;
  
  /* Check for the version of Stage 2.  */
  if (*((short *) (stage2_second_buffer + STAGE2_VER_MAJ_OFFS))
      != COMPAT_VERSION)
    {
      errnum = ERR_BAD_VERSION;
      goto fail;
    }

  /* Check for the Stage 2 id.  */
  if (stage2_second_buffer[STAGE2_STAGE2_ID] != STAGE2_ID_STAGE2)
    is_stage1_5 = 1;

  /* If INSTALLADDR is not specified explicitly in the command-line,
     determine it by the Stage 2 id.  */
  if (! installaddr)
    {
      if (! is_stage1_5)
	/* Stage 2.  */
	installaddr = 0x8000;
      else
	/* Stage 1.5.  */
	installaddr = 0x2000;
    }

  *((unsigned long *) (stage1_buffer + STAGE1_STAGE2_SECTOR))
    = stage2_first_sector;
  *((unsigned short *) (stage1_buffer + STAGE1_STAGE2_ADDRESS))
    = installaddr;
  *((unsigned short *) (stage1_buffer + STAGE1_STAGE2_SEGMENT))
    = installaddr >> 4;

  i = (int) stage2_first_buffer + SECTOR_SIZE - 4;
  while (*((unsigned long *) i))
    {
      if (i < (int) stage2_first_buffer
	  || (*((int *) (i - 4)) & 0x80000000)
	  || *((unsigned short *) i) >= 0xA00
	  || *((short *) (i + 2)) == 0)
	{
	  errnum = ERR_BAD_VERSION;
	  goto fail;
	}

      *((int *) i) = 0;
      *((int *) (i - 4)) = 0;
      i -= 8;
    }

  installlist = (int) stage2_first_buffer + SECTOR_SIZE + 4;
  installaddr += SECTOR_SIZE;
  
  /* Read the whole of Stage2 except for the first sector.  */
  grub_seek (SECTOR_SIZE);

  disk_read_hook = disk_read_blocklist_func;
  if (! grub_read (dummy, -1))
    goto fail;
  
  disk_read_hook = 0;
  
  /* Find a string for the configuration filename.  */
  config_file_location = stage2_second_buffer + STAGE2_VER_STR_OFFS;
  while (*(config_file_location++))
    ;

  /* Set the "force LBA" flag for Stage2.  */
  *((unsigned char *) (stage2_second_buffer + STAGE2_FORCE_LBA))
    = is_force_lba;
  
  if (*ptr == 'p')
    {
      *((long *) (stage2_second_buffer + STAGE2_INSTALLPART))
	= src_partition;
      if (is_stage1_5)
	{
	  /* Reset the device information in FILE if it is a Stage 1.5.  */
	  unsigned long device = 0xFFFFFFFF;

	  grub_memmove (config_file_location, (char *) &device,
			sizeof (device));
	}

      ptr = skip_to (0, ptr);
    }

  if (*ptr)
    {
      grub_strcpy (config_filename, ptr);
      nul_terminate (config_filename);
	
      if (! is_stage1_5)
	/* If it is a Stage 2, just copy PTR to CONFIG_FILE_LOCATION.  */
	grub_strcpy (config_file_location, ptr);
      else
	{
	  char *real_config;
	  unsigned long device;

	  /* Translate the external device syntax to the internal device
	     syntax.  */
	  if (! (real_config = set_device (ptr)))
	    {
	      /* The Stage 2 PTR does not contain the device name, so
		 use the root device instead.  */
	      errnum = ERR_NONE;
	      current_drive = saved_drive;
	      current_partition = saved_partition;
	      real_config = ptr;
	    }
	  
	  if (current_drive == src_drive)
	    {
	      /* If the drive where the Stage 2 resides is the same as
		 the one where the Stage 1.5 resides, do not embed the
		 drive number.  */
	      current_drive = GRUB_INVALID_DRIVE;
	    }

	  device = (current_drive << 24) | current_partition;
	  grub_memmove (config_file_location, (char *) &device,
			sizeof (device));
	  grub_strcpy (config_file_location + sizeof (device),
		       real_config);
	}

      /* If a Stage 1.5 is used, then we need to modify the Stage2.  */
      if (is_stage1_5)
	{
	  char *real_config_filename = skip_to (0, ptr);
	  
	  is_open = grub_open (config_filename);
	  if (! is_open)
	    goto fail;

	  /* Skip the first sector.  */
	  grub_seek (SECTOR_SIZE);
	  
	  disk_read_hook = disk_read_savesect_func;
	  if (grub_read (stage2_buffer, SECTOR_SIZE) != SECTOR_SIZE)
	    goto fail;
	  
	  disk_read_hook = 0;
	  grub_close ();
	  is_open = 0;
	  
	  /* Sanity check.  */
	  if (*(stage2_buffer + STAGE2_STAGE2_ID) != STAGE2_ID_STAGE2)
	    {
	      errnum = ERR_BAD_VERSION;
	      goto fail;
	    }

	  /* Set the "force LBA" flag for Stage2.  */
	  *(stage2_buffer + STAGE2_FORCE_LBA) = is_force_lba;

	  /* If REAL_CONFIG_FILENAME is specified, copy it to the Stage2.  */
	  if (*real_config_filename)
	    {
	      /* Specified */
	      char *location;
	      
	      /* Find a string for the configuration filename.  */
	      location = stage2_buffer + STAGE2_VER_STR_OFFS;
	      while (*(location++))
		;
	      
	      /* Copy the name.  */
	      grub_strcpy (location, real_config_filename);
	    }
	  
	  /* Write it to the disk.  */
	  buf_track = -1;

#ifdef GRUB_UTIL
	  /* In the grub shell, access the Stage 2 via the OS filesystem
	     service, if possible.  */
	  if (stage2_os_file)
	    {
	      FILE *fp;

	      fp = fopen (stage2_os_file, "r+");
	      if (! fp)
		{
		  errnum = ERR_FILE_NOT_FOUND;
		  goto fail;
		}

	      if (fseek (fp, SECTOR_SIZE, SEEK_SET) != 0)
		{
		  fclose (fp);
		  errnum = ERR_BAD_VERSION;
		  goto fail;
		}

	      if (fwrite (stage2_buffer, 1, SECTOR_SIZE, fp)
		  != SECTOR_SIZE)
		{
		  fclose (fp);
		  errnum = ERR_WRITE;
		  goto fail;
		}

	      fclose (fp);
	    }
	  else
#endif /* GRUB_UTIL */
	    {
	      if (! devwrite (saved_sector - part_start, 1, stage2_buffer))
		goto fail;
	    }
	}
    }

  /* Clear the cache.  */
  buf_track = -1;

  /* Write the modified sectors of Stage2 to the disk.  */
#ifdef GRUB_UTIL
  if (! is_stage1_5 && stage2_os_file)
    {
      FILE *fp;

      fp = fopen (stage2_os_file, "r+");
      if (! fp)
	{
	  errnum = ERR_FILE_NOT_FOUND;
	  goto fail;
	}

      if (fwrite (stage2_first_buffer, 1, SECTOR_SIZE, fp) != SECTOR_SIZE)
	{
	  fclose (fp);
	  errnum = ERR_WRITE;
	  goto fail;
	}

      if (fwrite (stage2_second_buffer, 1, SECTOR_SIZE, fp) != SECTOR_SIZE)
	{
	  fclose (fp);
	  errnum = ERR_WRITE;
	  goto fail;
	}

      fclose (fp);
    }
  else
#endif /* GRUB_UTIL */
    {
      /* The first.  */
      current_drive = src_drive;
      current_partition = src_partition;

      if (! open_partition ())
	goto fail;

      if (! devwrite (stage2_first_sector - src_part_start, 1,
		      stage2_first_buffer))
	goto fail;

      if (! devwrite (stage2_second_sector - src_part_start, 1,
		      stage2_second_buffer))
	goto fail;
    }
  
  /* Write the modified sector of Stage 1 to the disk.  */
  current_drive = dest_drive;
  current_partition = dest_partition;
  if (! open_partition ())
    goto fail;

  devwrite (0, 1, stage1_buffer);

 fail:
  if (is_open)
    grub_close ();
  
  disk_read_hook = 0;
  
#ifndef NO_DECOMPRESSION
  no_decompression = 0;
#endif

  return errnum;
}

static struct builtin builtin_install =
{
  "install",
  install_func,
  BUILTIN_CMDLINE,
  "install [--stage2=STAGE2_FILE] [--force-lba] STAGE1 [d] DEVICE STAGE2 [ADDR] [p] [CONFIG_FILE] [REAL_CONFIG_FILE]",
  "Install STAGE1 on DEVICE, and install a blocklist for loading STAGE2"
  " as a Stage 2. If the option `d' is present, the Stage 1 will always"
  " look for the disk where STAGE2 was installed, rather than using"
  " the booting drive. The Stage 2 will be loaded at address ADDR, which"
  " will be determined automatically if you don't specify it. If"
  " the option `p' or CONFIG_FILE is present, then the first block"
  " of Stage 2 is patched with new values of the partition and name"
  " of the configuration file used by the true Stage 2 (for a Stage 1.5,"
  " this is the name of the true Stage 2) at boot time. If STAGE2 is a Stage"
  " 1.5 and REAL_CONFIG_FILE is present, then the Stage 2 CONFIG_FILE is"
  " patched with the configuration filename REAL_CONFIG_FILE."
  " If the option `--force-lba' is specified, disable some sanity checks"
  " for LBA mode. If the option `--stage2' is specified, rewrite the Stage"
  " 2 via your OS's filesystem instead of the raw device."
};


/* ioprobe */
static int
ioprobe_func (char *arg, int flags)
{
#ifdef GRUB_UTIL