/*
 *  GRUB  --  GRand Unified Bootloader
 *  Copyright (C) 2010  Free Software Foundation, Inc.
 *
 *  GRUB 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 3 of the License, or
 *  (at your option) any later version.
 *
 *  GRUB 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 GRUB.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <grub/loader.h>
#include <grub/file.h>
#include <grub/err.h>
#include <grub/device.h>
#include <grub/disk.h>
#include <grub/misc.h>
#include <grub/types.h>
#include <grub/partition.h>
#include <grub/msdos_partition.h>
#include <grub/scsi.h>
#include <grub/dl.h>
#include <grub/command.h>
#include <grub/i18n.h>
#include <grub/video.h>
#include <grub/mm.h>
#include <grub/cpu/relocator.h>
#include <grub/extcmd.h>

GRUB_MOD_LICENSE ("GPLv3+");

static grub_dl_t my_mod;
static struct grub_relocator *rel;
static grub_uint32_t eip = 0xffffffff;

#define GRUB_PLAN9_TARGET            0x100000
#define GRUB_PLAN9_ALIGN             4096
#define GRUB_PLAN9_CONFIG_ADDR       0x001200
#define GRUB_PLAN9_CONFIG_PATH_SIZE  0x000040
#define GRUB_PLAN9_CONFIG_MAGIC      "ZORT 0\r\n"

static const struct grub_arg_option options[] =
  {
    {"map", 'm', GRUB_ARG_OPTION_REPEATABLE,
     N_("Override guessed mapping of Plan9 devices."), 
     N_("GRUBDEVICE=PLAN9DEVICE"),
     ARG_TYPE_STRING},
    {0, 0, 0, 0, 0, 0}
  };

struct grub_plan9_header
{
  grub_uint32_t magic;
#define GRUB_PLAN9_MAGIC 0x1eb
  grub_uint32_t text_size;
  grub_uint32_t data_size;
  grub_uint32_t bss_size;
  grub_uint32_t sectiona;
  grub_uint32_t entry_addr;
  grub_uint32_t zero;
  grub_uint32_t sectionb;
};

static grub_err_t
grub_plan9_boot (void)
{
  struct grub_relocator32_state state = { 
    .eax = 0,
    .eip = eip,
    .ebx = 0,
    .ecx = 0,
    .edx = 0,
    .edi = 0,
    .esp = 0,
    .ebp = 0,
    .esi = 0
  };
  grub_video_set_mode ("text", 0, 0);

  return grub_relocator32_boot (rel, state);
}

static grub_err_t
grub_plan9_unload (void)
{
  grub_relocator_unload (rel);
  rel = NULL;
  grub_dl_unref (my_mod);
  return GRUB_ERR_NONE;
}

static grub_err_t
grub_cmd_plan9 (grub_extcmd_context_t ctxt, int argc, char *argv[])
{
  grub_file_t file = 0;
  void *mem;
  grub_size_t memsize, padsize;
  struct grub_plan9_header hdr;
  char *config, *configptr;
  grub_size_t configsize;
  char *pmap = NULL;
  grub_size_t pmapalloc = 256;
  grub_size_t pmapptr = 0;
  int noslash = 1;
  char prefixes[5][10] = {"dos", "plan9", "ntfs", "linux", "linuxswap"};
  int prefixescnt[5];
  char *bootdisk = NULL, *bootpart = NULL, *bootpath = NULL;

  auto int fill_partition (grub_disk_t disk,
			   const grub_partition_t partition);
  int fill_partition (grub_disk_t disk,
		      const grub_partition_t partition)
  {
    int file_disk = 0;
    int pstart, pend;
    if (!noslash)
      {
	if (grub_extend_alloc (pmapptr + 1, &pmapalloc, (void **) &pmap))
	  return 1;
	pmap[pmapptr++] = '/';
      }
    noslash = 0;

    file_disk = file->device->disk && disk->id == file->device->disk->id
      && disk->dev->id == file->device->disk->dev->id;

    pstart = pmapptr;
    if (grub_strcmp (partition->partmap->name, "plan") == 0)
      {
	unsigned ptr = partition->index + sizeof ("part ") - 1;
	grub_err_t err;
	disk->partition = partition->parent;
	do
	  {
	    if (grub_extend_alloc (pmapptr + 1, &pmapalloc, (void **) &pmap))
	      return 1;
	    err = grub_disk_read (disk, 1, ptr, 1, pmap + pmapptr);
	    if (err)
	      {
		disk->partition = 0;
		return err;
	      }
	    ptr++;
	    pmapptr++;
	  }
	while (grub_isalpha (pmap[pmapptr - 1])
	       || grub_isdigit (pmap[pmapptr - 1]));
	pmapptr--;
      }
    else
      {
	char name[50];
	int c = 0;
	if (grub_strcmp (partition->partmap->name, "msdos") == 0)
	  {
	    switch (partition->msdostype)
	      {
	      case GRUB_PC_PARTITION_TYPE_PLAN9:
		c = 1;
		break;
	      case GRUB_PC_PARTITION_TYPE_NTFS:
		c = 2;
		break;
	      case GRUB_PC_PARTITION_TYPE_MINIX:
	      case GRUB_PC_PARTITION_TYPE_LINUX_MINIX:
	      case GRUB_PC_PARTITION_TYPE_EXT2FS:
		c = 3;
		break;
	      case GRUB_PC_PARTITION_TYPE_LINUX_SWAP:
		c = 4;
		break;
	      }
	  }

	if (prefixescnt[c] == 0)
	  grub_strcpy (name, prefixes[c]);
	else
	  grub_snprintf (name, sizeof (name), "%s.%d", prefixes[c],
			 prefixescnt[c]);
	prefixescnt[c]++;
	if (grub_extend_alloc (pmapptr + grub_strlen (name) + 1,
			       &pmapalloc, (void **) &pmap))
	  return 1;
	grub_strcpy (pmap + pmapptr, name);
	pmapptr += grub_strlen (name);
      }
    pend = pmapptr;
    if (grub_extend_alloc (pmapptr + 2 + 25 + 5 + 25, &pmapalloc,
			   (void **) &pmap))
      return 1;
    pmap[pmapptr++] = ' ';
    grub_snprintf (pmap + pmapptr, 25 + 5 + 25,
		   "%" PRIuGRUB_UINT64_T " %" PRIuGRUB_UINT64_T,
		   grub_partition_get_start (partition),
		   grub_partition_get_start (partition)
		   + grub_partition_get_len (partition));
    if (file_disk && grub_partition_get_start (partition)
	== grub_partition_get_start (file->device->disk->partition)
	&& grub_partition_get_len (partition)
	== grub_partition_get_len (file->device->disk->partition))
      {
	grub_free (bootpart);
	bootpart = grub_strndup (pmap + pstart, pend - pstart);
      }

    pmapptr += grub_strlen (pmap + pmapptr);
    return 0;
  }

  auto int fill_disk (const char *name);
  int fill_disk (const char *name)
  {
    grub_device_t dev;
    char *plan9name = NULL;
    unsigned i;
    int file_disk = 0;

    dev = grub_device_open (name);
    if (!dev)
      {
	grub_print_error ();
	return 0;
      }
    if (!dev->disk)
      {
	grub_device_close (dev);
	return 0;
      }
    file_disk = file->device->disk && dev->disk->id == file->device->disk->id
      && dev->disk->dev->id == file->device->disk->dev->id;
    for (i = 0; ctxt->state[0].args && ctxt->state[0].args[i]; i++)
      if (grub_strncmp (name, ctxt->state[0].args[i], grub_strlen (name)) == 0
	  && ctxt->state[0].args[i][grub_strlen (name)] == '=')
	break;
    if (ctxt->state[0].args && ctxt->state[0].args[i])
      plan9name = grub_strdup (ctxt->state[0].args[i] + grub_strlen (name) + 1);
    else
      switch (dev->disk->dev->id)
	{
	case GRUB_DISK_DEVICE_BIOSDISK_ID:
	  if (dev->disk->id & 0x80)
	    plan9name = grub_xasprintf ("sdB%u",
					(unsigned) (dev->disk->id & 0x7f));
	  else
	    plan9name = grub_xasprintf ("fd%u",
					(unsigned) (dev->disk->id & 0x7f));
	  break;
	  /* Shouldn't happen as Plan9 doesn't work on these platforms.  */
	case GRUB_DISK_DEVICE_OFDISK_ID:
	case GRUB_DISK_DEVICE_EFIDISK_ID:

	  /* Plan9 doesn't see those.  */
	default:

	  /* Not sure how to handle those. */
	case GRUB_DISK_DEVICE_NAND_ID:
	  if (!file_disk)
	    {
	      grub_device_close (dev);
	      return 0;
	    }
	  
	  /* if it's the disk the kernel is loaded from we need to name
	     it nevertheless.  */
	  plan9name = grub_strdup ("sdZ0");
	  break;

	case GRUB_DISK_DEVICE_ATA_ID:
	  {
	    int unit;
	    if (grub_strlen (dev->disk->name) < sizeof ("ata0") - 1)
	      unit = 0;
	    else
	      unit = grub_strtoul (dev->disk->name + sizeof ("ata0") - 1, 0, 0);
	    plan9name = grub_xasprintf ("sd%c%d", 'C' + unit / 2, unit % 2);
	  }
	  break;
	case GRUB_DISK_DEVICE_SCSI_ID:
	  if (((dev->disk->id >> GRUB_SCSI_ID_SUBSYSTEM_SHIFT) & 0xff)
	      == GRUB_SCSI_SUBSYSTEM_PATA)
	    {
	      int unit;
	      if (grub_strlen (dev->disk->name) < sizeof ("ata0") - 1)
		unit = 0;
	      else
		unit = grub_strtoul (dev->disk->name + sizeof ("ata0") - 1,
				     0, 0);
	      plan9name = grub_xasprintf ("sd%c%d", 'C' + unit / 2, unit % 2);
	      break;
	    }
	  
	  /* FIXME: how does Plan9 number controllers?
	     We probably need save the SCSI devices and sort them  */
	  plan9name
	    = grub_xasprintf ("sd0%u", (unsigned)
			      ((dev->disk->id >> GRUB_SCSI_ID_BUS_SHIFT)
			       & 0xf));
	  break;
	}
    if (!plan9name)
      {
	grub_print_error ();
	return 0;
      }
    if (grub_extend_alloc (pmapptr + grub_strlen (plan9name)
			   + sizeof ("part="), &pmapalloc,
			   (void **) &pmap))
      {
	grub_free (plan9name);
	return 1;
      }
    grub_strcpy (pmap + pmapptr, plan9name);
    pmapptr += grub_strlen (plan9name);
    if (!file_disk)
      grub_free (plan9name);
    else
      {
	grub_free (bootdisk);
	bootdisk = plan9name;
      }
    grub_strcpy (pmap + pmapptr, "part=");
    pmapptr += sizeof ("part=") - 1;

    noslash = 1;
    grub_memset (prefixescnt, 0, sizeof (prefixescnt));
    if (grub_partition_iterate (dev->disk, fill_partition))
      return 1;
    if (grub_extend_alloc (pmapptr + 1, &pmapalloc, (void **) &pmap))
      return 1;
    pmap[pmapptr++] = '\n';

    return 0;
  }

  if (argc == 0)
    return grub_error (GRUB_ERR_BAD_ARGUMENT, "no file specified");

  grub_dl_ref (my_mod);

  rel = grub_relocator_new ();
  if (!rel)
    goto fail;

  file = grub_file_open (argv[0]);
  if (! file)
    goto fail;

  pmap = grub_malloc (pmapalloc);
  if (!pmap)
    goto fail;

  if (grub_disk_dev_iterate (fill_disk))
    goto fail;

  if (grub_extend_alloc (pmapptr + 1, &pmapalloc,
			 (void **) &pmap))
    goto fail;
  pmap[pmapptr] = 0;

  {
    char *file_name = grub_strchr (argv[0], ')');
    if (file_name)
      file_name++;
    else
      file_name = argv[0];
    if (*file_name)
      file_name++;

    if (bootpart)
      bootpath = grub_xasprintf ("%s!%s!%s", bootdisk, bootpart, file_name);
    else
      bootpath = grub_xasprintf ("%s!%s", bootdisk, file_name);
    grub_free (bootdisk);
    grub_free (bootpart);
  }
  if (!bootpath)
    goto fail;

  if (grub_file_read (file, &hdr, sizeof (hdr)) != (grub_ssize_t) sizeof (hdr))
    goto fail;

  if (grub_be_to_cpu32 (hdr.magic) != GRUB_PLAN9_MAGIC
      || hdr.zero)
    {
      grub_error (GRUB_ERR_BAD_OS, "unsupported Plan9");
      goto fail;
    }

  memsize = ALIGN_UP (grub_be_to_cpu32 (hdr.text_size) + sizeof (hdr),
		       GRUB_PLAN9_ALIGN);
  memsize += ALIGN_UP (grub_be_to_cpu32 (hdr.data_size), GRUB_PLAN9_ALIGN);
  memsize += ALIGN_UP(grub_be_to_cpu32 (hdr.bss_size), GRUB_PLAN9_ALIGN);
  eip = grub_be_to_cpu32 (hdr.entry_addr) & 0xfffffff;

  /* path */
  configsize = GRUB_PLAN9_CONFIG_PATH_SIZE;
  /* magic */
  configsize += sizeof (GRUB_PLAN9_CONFIG_MAGIC) - 1;
  {
    int i;
    for (i = 1; i < argc; i++)
      configsize += grub_strlen (argv[i]) + 1;
  }
  configsize += (sizeof ("bootfile=") - 1) + grub_strlen (bootpath) + 1;
  configsize += pmapptr;
  /* Terminating \0.  */
  configsize++;

  {
    grub_relocator_chunk_t ch;
    grub_err_t err;
    err = grub_relocator_alloc_chunk_addr (rel, &ch, GRUB_PLAN9_CONFIG_ADDR,
					   configsize);
    if (err)
      goto fail;
    config = get_virtual_current_address (ch);
  }

  grub_memset (config, 0, GRUB_PLAN9_CONFIG_PATH_SIZE);
  grub_strncpy (config, bootpath, GRUB_PLAN9_CONFIG_PATH_SIZE - 1);

  configptr = config + GRUB_PLAN9_CONFIG_PATH_SIZE;
  grub_memcpy (configptr, GRUB_PLAN9_CONFIG_MAGIC,
	       sizeof (GRUB_PLAN9_CONFIG_MAGIC) - 1);
  configptr += sizeof (GRUB_PLAN9_CONFIG_MAGIC) - 1;
  configptr = grub_stpcpy (configptr, "bootfile=");
  configptr = grub_stpcpy (configptr, bootpath);
  *configptr++ = '\n';
  {
    int i;
    for (i = 1; i < argc; i++)
      {
	configptr = grub_stpcpy (configptr, argv[i]);
	*configptr++ = '\n';
      }
  }
  configptr = grub_stpcpy (configptr, pmap);

  {
    grub_relocator_chunk_t ch;
    grub_err_t err;

    err = grub_relocator_alloc_chunk_addr (rel, &ch, GRUB_PLAN9_TARGET,
					   memsize);
    if (err)
      goto fail;
    mem = get_virtual_current_address (ch);
  }

  {
    grub_uint8_t *ptr;
    ptr = mem;
    grub_memcpy (ptr, &hdr, sizeof (hdr));
    ptr += sizeof (hdr);

    if (grub_file_read (file, ptr, grub_be_to_cpu32 (hdr.text_size))
	!= (grub_ssize_t) grub_be_to_cpu32 (hdr.text_size))
      goto fail;
    ptr += grub_be_to_cpu32 (hdr.text_size);
    padsize = ALIGN_UP (grub_be_to_cpu32 (hdr.text_size) + sizeof (hdr),
			GRUB_PLAN9_ALIGN) - grub_be_to_cpu32 (hdr.text_size)
      - sizeof (hdr);

    grub_memset (ptr, 0, padsize);
    ptr += padsize;

    if (grub_file_read (file, ptr, grub_be_to_cpu32 (hdr.data_size))
	!= (grub_ssize_t) grub_be_to_cpu32 (hdr.data_size))
      goto fail;
    ptr += grub_be_to_cpu32 (hdr.data_size);
    padsize = ALIGN_UP (grub_be_to_cpu32 (hdr.data_size), GRUB_PLAN9_ALIGN)
      - grub_be_to_cpu32 (hdr.data_size);

    grub_memset (ptr, 0, padsize);
    ptr += padsize;
    grub_memset (ptr, 0, ALIGN_UP(grub_be_to_cpu32 (hdr.bss_size),
				  GRUB_PLAN9_ALIGN));
  }
  grub_loader_set (grub_plan9_boot, grub_plan9_unload, 1);
  return GRUB_ERR_NONE;

 fail:
  grub_free (pmap);

  if (file)
    grub_file_close (file);

  grub_plan9_unload ();

  return grub_errno;
}

static grub_extcmd_t cmd;

GRUB_MOD_INIT(plan9)
{
  cmd = grub_register_extcmd ("plan9", grub_cmd_plan9,
			      GRUB_COMMAND_OPTIONS_AT_START,
			      N_("KERNEL ARGS"), N_("Load Plan9 kernel."),
			      options);
  my_mod = mod;
}

GRUB_MOD_FINI(plan9)
{
  grub_unregister_extcmd (cmd);
}