builtins.c

i386的bootloader源码grub

/* builtins.c - the GRUB builtin commands */
/*
 *  GRUB  --  GRand Unified Bootloader
 *  Copyright (C) 1999,2000,2001,2002,2003,2004  Free Software Foundation, Inc.
 *
 *  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.
 *
 *  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., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

/* Include stdio.h before shared.h, because we can't define
   WITHOUT_LIBC_STUBS here.  */
#ifdef GRUB_UTIL
# include <stdio.h>
#endif

#include <shared.h>
#include <filesys.h>
#include <term.h>

#ifdef SUPPORT_NETBOOT
# define GRUB	1
# include <etherboot.h>
#endif

#ifdef SUPPORT_SERIAL
# include <serial.h>
# include <terminfo.h>
#endif

#ifdef GRUB_UTIL
# include <device.h>
#else /* ! GRUB_UTIL */
# include <apic.h>
# include <smp-imps.h>
#endif /* ! GRUB_UTIL */

#ifdef USE_MD5_PASSWORDS
# include <md5.h>
#endif

/* The type of kernel loaded.  */
kernel_t kernel_type;
/* The boot device.  */
static int bootdev;
/* True when the debug mode is turned on, and false
   when it is turned off.  */
int debug = 0;
/* The default entry.  */
int default_entry = 0;
/* The fallback entry.  */
int fallback_entry = -1;
/* The number of current entry.  */
int current_entryno;
/* The address for Multiboot command-line buffer.  */
static char *mb_cmdline;
/* The password.  */
char *password;
/* The password type.  */
password_t password_type;
/* The flag for indicating that the user is authoritative.  */
int auth = 0;
/* The timeout.  */
int grub_timeout = -1;
/* Whether to show the menu or not.  */
int show_menu = 1;
/* The BIOS drive map.  */
static unsigned short bios_drive_map[DRIVE_MAP_SIZE + 1];

/* Prototypes for allowing straightfoward calling of builtins functions
   inside other functions.  */
static int configfile_func (char *arg, int flags);

/* Initialize the data for builtins.  */
void
init_builtins (void)
{
  kernel_type = KERNEL_TYPE_NONE;
  /* BSD and chainloading evil hacks!  */
  bootdev = set_bootdev (0);
  mb_cmdline = (char *) MB_CMDLINE_BUF;
}

/* Initialize the data for the configuration file.  */
void
init_config (void)
{
  default_entry = 0;
  password = 0;
  fallback_entry = -1;
  grub_timeout = -1;
}

/* Check a password for correctness.  Returns 0 if password was
   correct, and a value != 0 for error, similarly to strcmp. */
int
check_password (char *entered, char* expected, password_t type)
{
  switch (type)
    {
    case PASSWORD_PLAIN:
      return strcmp (entered, expected);

#ifdef USE_MD5_PASSWORDS
    case PASSWORD_MD5:
      return check_md5_password (entered, expected);
#endif
    default: 
      /* unsupported password type: be secure */
      return 1;
    }
}

/* Print which sector is read when loading a file.  */
static void
disk_read_print_func (int sector, int offset, int length)
{
  grub_printf ("[%d,%d,%d]", sector, offset, length);
}


/* blocklist */
static int
blocklist_func (char *arg, int flags)
{
  char *dummy = (char *) RAW_ADDR (0x100000);
  int start_sector;
  int num_sectors = 0;
  int num_entries = 0;
  int last_length = 0;

  /* Collect contiguous blocks into one entry as many as possible,
     and print the blocklist notation on the screen.  */
  static void disk_read_blocklist_func (int sector, int offset, int length)
    {
      if (num_sectors > 0)
	{
	  if (start_sector + num_sectors == sector
	      && offset == 0 && last_length == SECTOR_SIZE)
	    {
	      num_sectors++;
	      last_length = length;
	      return;
	    }
	  else
	    {
	      if (last_length == SECTOR_SIZE)
		grub_printf ("%s%d+%d", num_entries ? "," : "",
			     start_sector - part_start, num_sectors);
	      else if (num_sectors > 1)
		grub_printf ("%s%d+%d,%d[0-%d]", num_entries ? "," : "",
			     start_sector - part_start, num_sectors-1,
			     start_sector + num_sectors-1 - part_start, 
			     last_length);
	      else
		grub_printf ("%s%d[0-%d]", num_entries ? "," : "",
			     start_sector - part_start, last_length);
	      num_entries++;
	      num_sectors = 0;
	    }
	}

      if (offset > 0)
	{
	  grub_printf("%s%d[%d-%d]", num_entries ? "," : "",
		      sector-part_start, offset, offset+length);
	  num_entries++;
	}
      else
	{
	  start_sector = sector;
	  num_sectors = 1;
	  last_length = length;
	}
    }

  /* Open the file.  */
  if (! grub_open (arg))
    return 1;

  /* Print the device name.  */
  grub_printf ("(%cd%d",
	       (current_drive & 0x80) ? 'h' : 'f',
	       current_drive & ~0x80);
  
  if ((current_partition & 0xFF0000) != 0xFF0000)
    grub_printf (",%d", (current_partition >> 16) & 0xFF);
  
  if ((current_partition & 0x00FF00) != 0x00FF00)
    grub_printf (",%c", 'a' + ((current_partition >> 8) & 0xFF));
  
  grub_printf (")");

  /* Read in the whole file to DUMMY.  */
  disk_read_hook = disk_read_blocklist_func;
  if (! grub_read (dummy, -1))
    goto fail;

  /* The last entry may not be printed yet.  Don't check if it is a
   * full sector, since it doesn't matter if we read too much. */
  if (num_sectors > 0)
    grub_printf ("%s%d+%d", num_entries ? "," : "",
		 start_sector - part_start, num_sectors);

  grub_printf ("\n");
  
 fail:
  disk_read_hook = 0;
  grub_close ();
  return errnum;
}

static struct builtin builtin_blocklist =
{
  "blocklist",
  blocklist_func,
  BUILTIN_CMDLINE | BUILTIN_HELP_LIST,
  "blocklist FILE",
  "Print the blocklist notation of the file FILE."
};

/* boot */
static int
boot_func (char *arg, int flags)
{
  /* Clear the int15 handler if we can boot the kernel successfully.
     This assumes that the boot code never fails only if KERNEL_TYPE is
     not KERNEL_TYPE_NONE. Is this assumption is bad?  */
  if (kernel_type != KERNEL_TYPE_NONE)
    unset_int15_handler ();

#ifdef SUPPORT_NETBOOT
  /* Shut down the networking.  */
  cleanup_net ();
#endif
  
  switch (kernel_type)
    {
    case KERNEL_TYPE_FREEBSD:
    case KERNEL_TYPE_NETBSD:
      /* *BSD */
      bsd_boot (kernel_type, bootdev, (char *) mbi.cmdline);
      break;

    case KERNEL_TYPE_LINUX:
      /* Linux */
      linux_boot ();
      break;

    case KERNEL_TYPE_BIG_LINUX:
      /* Big Linux */
      big_linux_boot ();
      break;

    case KERNEL_TYPE_CHAINLOADER:
      /* Chainloader */
      
      /* Check if we should set the int13 handler.  */
      if (bios_drive_map[0] != 0)
	{
	  int i;
	  
	  /* Search for SAVED_DRIVE.  */
	  for (i = 0; i < DRIVE_MAP_SIZE; i++)
	    {
	      if (! bios_drive_map[i])
		break;
	      else if ((bios_drive_map[i] & 0xFF) == saved_drive)
		{
		  /* Exchage SAVED_DRIVE with the mapped drive.  */
		  saved_drive = (bios_drive_map[i] >> 8) & 0xFF;
		  break;
		}
	    }
	  
	  /* Set the handler. This is somewhat dangerous.  */
	  set_int13_handler (bios_drive_map);
	}
      
      gateA20 (0);
      boot_drive = saved_drive;
      chain_stage1 (0, BOOTSEC_LOCATION, boot_part_addr);
      break;

    case KERNEL_TYPE_MULTIBOOT:
      /* Multiboot */
      multi_boot ((int) entry_addr, (int) &mbi);
      break;

    default:
      errnum = ERR_BOOT_COMMAND;
      return 1;
    }

  return 0;
}

static struct builtin builtin_boot =
{
  "boot",
  boot_func,
  BUILTIN_CMDLINE | BUILTIN_HELP_LIST,
  "boot",
  "Boot the OS/chain-loader which has been loaded."
};


#ifdef SUPPORT_NETBOOT
/* bootp */
static int
bootp_func (char *arg, int flags)
{
  int with_configfile = 0;

  if (grub_memcmp (arg, "--with-configfile", sizeof ("--with-configfile") - 1)
      == 0)
    {
      with_configfile = 1;
      arg = skip_to (0, arg);
    }
  
  if (! bootp ())
    {
      if (errnum == ERR_NONE)
	errnum = ERR_DEV_VALUES;

      return 1;
    }

  /* Notify the configuration.  */
  print_network_configuration ();

  /* XXX: this can cause an endless loop, but there is no easy way to
     detect such a loop unfortunately.  */
  if (with_configfile)
    configfile_func (config_file, flags);
  
  return 0;
}

static struct builtin builtin_bootp =
{
  "bootp",
  bootp_func,
  BUILTIN_CMDLINE | BUILTIN_MENU | BUILTIN_HELP_LIST,
  "bootp [--with-configfile]",
  "Initialize a network device via BOOTP. If the option `--with-configfile'"
  " is given, try to load a configuration file specified by the 150 vendor"
  " tag."
};
#endif /* SUPPORT_NETBOOT */


/* cat */
static int
cat_func (char *arg, int flags)
{
  char c;

  if (! grub_open (arg))
    return 1;

  while (grub_read (&c, 1))
    {
      /* Because running "cat" with a binary file can confuse the terminal,
	 print only some characters as they are.  */
      if (grub_isspace (c) || (c >= ' ' && c <= '~'))
	grub_putchar (c);
      else
	grub_putchar ('?');
    }
  
  grub_close ();
  return 0;
}

static struct builtin builtin_cat =
{
  "cat",
  cat_func,
  BUILTIN_CMDLINE | BUILTIN_HELP_LIST,
  "cat FILE",
  "Print the contents of the file FILE."
};


/* chainloader */
static int
chainloader_func (char *arg, int flags)
{
  int force = 0;
  char *file = arg;

  /* If the option `--force' is specified?  */
  if (substring ("--force", arg) <= 0)
    {
      force = 1;
      file = skip_to (0, arg);
    }

  /* Open the file.  */
  if (! grub_open (file))
    {
      kernel_type = KERNEL_TYPE_NONE;
      return 1;
    }

  /* Read the first block.  */
  if (grub_read ((char *) BOOTSEC_LOCATION, SECTOR_SIZE) != SECTOR_SIZE)
    {
      grub_close ();
      kernel_type = KERNEL_TYPE_NONE;

      /* This below happens, if a file whose size is less than 512 bytes
	 is loaded.  */
      if (errnum == ERR_NONE)
	errnum = ERR_EXEC_FORMAT;
      
      return 1;
    }

  /* If not loading it forcibly, check for the signature.  */
  if (! force
      && (*((unsigned short *) (BOOTSEC_LOCATION + BOOTSEC_SIG_OFFSET))
	  != BOOTSEC_SIGNATURE))
    {
      grub_close ();
      errnum = ERR_EXEC_FORMAT;
      kernel_type = KERNEL_TYPE_NONE;
      return 1;
    }

  grub_close ();
  kernel_type = KERNEL_TYPE_CHAINLOADER;

  /* XXX: Windows evil hack. For now, only the first five letters are
     checked.  */
  if (IS_PC_SLICE_TYPE_FAT (current_slice)
      && ! grub_memcmp ((char *) BOOTSEC_LOCATION + BOOTSEC_BPB_SYSTEM_ID,
			"MSWIN", 5))
    *((unsigned long *) (BOOTSEC_LOCATION + BOOTSEC_BPB_HIDDEN_SECTORS))
      = part_start;

  errnum = ERR_NONE;
  
  return 0;
}

static struct builtin builtin_chainloader =
{
  "chainloader",
  chainloader_func,
  BUILTIN_CMDLINE | BUILTIN_HELP_LIST,
  "chainloader [--force] FILE",
  "Load the chain-loader FILE. If --force is specified, then load it"
  " forcibly, whether the boot loader signature is present or not."
};


/* This function could be used to debug new filesystem code. Put a file
   in the new filesystem and the same file in a well-tested filesystem.
   Then, run "cmp" with the files. If no output is obtained, probably
   the code is good, otherwise investigate what's wrong...  */
/* cmp FILE1 FILE2 */
static int
cmp_func (char *arg, int flags)
{
  /* The filenames.  */
  char *file1, *file2;
  /* The addresses.  */
  char *addr1, *addr2;
  int i;
  /* The size of the file.  */
  int size;

  /* Get the filenames from ARG.  */
  file1 = arg;
  file2 = skip_to (0, arg);
  if (! *file1 || ! *file2)
    {
      errnum = ERR_BAD_ARGUMENT;
      return 1;
    }

  /* Terminate the filenames for convenience.  */
  nul_terminate (file1);
  nul_terminate (file2);

  /* Read the whole data from FILE1.  */
  addr1 = (char *) RAW_ADDR (0x100000);
  if (! grub_open (file1))
    return 1;
  
  /* Get the size.  */
  size = filemax;
  if (grub_read (addr1, -1) != size)
    {
      grub_close ();
      return 1;
    }
  
  grub_close ();

  /* Read the whole data from FILE2.  */
  addr2 = addr1 + size;
  if (! grub_open (file2))
    return 1;

  /* Check if the size of FILE2 is equal to the one of FILE2.  */
  if (size != filemax)
    {
      grub_printf ("Differ in size: 0x%x [%s], 0x%x [%s]\n",
		   size, file1, filemax, file2);
      grub_close ();
      return 0;
    }
  
  if (! grub_read (addr2, -1))
    {
      grub_close ();
      return 1;
    }
  
  grub_close ();

  /* Now compare ADDR1 with ADDR2.  */
  for (i = 0; i < size; i++)
    {
      if (addr1[i] != addr2[i])
	grub_printf ("Differ at the offset %d: 0x%x [%s], 0x%x [%s]\n",
		     i, (unsigned) addr1[i], file1,
		     (unsigned) addr2[i], file2);
    }
  
  return 0;
}

static struct builtin builtin_cmp =
{
  "cmp",
  cmp_func,
  BUILTIN_CMDLINE,
  "cmp FILE1 FILE2",
  "Compare the file FILE1 with the FILE2 and inform the different values"
  " if any."
};


/* color */
/* Set new colors used for the menu interface. Support two methods to
   specify a color name: a direct integer representation and a symbolic
   color name. An example of the latter is "blink-light-gray/blue".  */
static int