path: root/isofs/inode.c

/* 
   Copyright (C) 1997 Free Software Foundation, Inc.
   Written by Thomas Bushnell, n/BSG.

   This file is part of the GNU Hurd.

   The GNU Hurd 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, or (at
   your option) any later version.

   The GNU Hurd 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., 59 Temple Place - Suite 330, Boston, MA  02111, USA. */

#include <string.h>
#include <stdio.h>
#include "isofs.h"


/* There is no such thing as an inode in this format, all such information
   being recorded in the directory entry.  So we report inode numbers as
   absolute offsets from DISK_IMAGE. */

#define	INOHSZ	512
#if	((INOHSZ&(INOHSZ-1)) == 0)
#define	INOHASH(ino)	((ino>>8)&(INOHSZ-1))
#else
#define	INOHASH(ino)	(((unsigned)(ino>>8))%INOHSZ)
#endif

struct node_cache
{
  struct dirrect *dr;		/* somewhere in disk_image */

  off_t file_start;		/* UNIQUE start of file */
  
  struct node *np;		/* if live */
};

static int node_cache_size = 0;
static int node_cache_alloced = 0;
struct node_cache *node_cache = 0;

/* Forward */
static error_t read_disknode (struct node *, 
			      struct dirrect *, struct rrip_lookup *);
 

/* See if node with file start FILE_START is in the cache.  If so,
   return it, with one additional reference. diskfs_node_refcnt_lock must
   be held on entry to the call, and will be released iff the node
   was found in the cache. */
void
inode_cache_find (off_t file_start, struct node **npp)
{
  int i;

  for (i = 0; i < node_cache_size; i++)
    if (node_cache[i].file_start == file_start
	&& node_cache[i].np)
      {
	*npp = node_cache[i].np;
	(*npp)->references++;
	spin_unlock (&diskfs_node_refcnt_lock);
	mutex_lock (&(*npp)->lock);
	return;
      }
  *npp = 0;
}

/* Enter NP into the cache.  The directory entry we used
   DR. diskfs_node_refcnt_lock must be held. */
void
cache_inode (struct dirrect *dr, struct node *np)
{
  int i;
  struct node_cache *c = 0;

  /* First see if there's already an entry. */
  for (i = 0; i < node_cache_size; i++)
    if (node_cache[i].file_start == np->dn->file_start)
      break;
  
  if (i == node_cache_size)
    {
      if (node_cache_size >= node_cache_alloced)
	{
	  if (!node_cache_alloced)
	    {
	      /* Initialize */
	      node_cache_alloced = 10;
	      node_cache = malloc (sizeof (struct node_cache) * 10);
	    }
	  else
	    {
	      node_cache_alloced *= 2;
	      node_cache = realloc (node_cache, 
				    sizeof (struct node_cache)
				    * node_cache_alloced);
	    }
	  assert (node_cache);
	}
      node_cache_size++;
    }
  
  c = &node_cache[i];
  c->dr = dr;
  c->file_start = np->dn->file_start;
  c->np = np;

  /* PLUS 1 so that we don't store zero cache ID's (not allowed by diskfs) */
  np->cache_id = i + 1;
}

/* Fetch inode with cache id ID; set *NPP to the node structure;
   gain one user reference and lock the node. */
error_t
diskfs_cached_lookup (int id, struct node **npp)
{
  struct node *np;
  error_t err;

  /* Cache ID's are incremented when presented to diskfs
     to avoid presenting zero cache ID's. */
  id--;

  spin_lock (&diskfs_node_refcnt_lock);
  assert (id < node_cache_size);

  np = node_cache[id].np;
  
  if (!np)
    {
      struct node_cache *c = &node_cache[id];
      struct rrip_lookup rr;
      struct disknode *dn;

      rrip_lookup (node_cache[id].dr, &rr, 1);
      
      /* We should never cache the wrong directory entry */
      assert (!(rr.valid & VALID_CL));

      dn = malloc (sizeof (struct disknode));
      dn->fileinfo = 0;
      dn->file_start = c->file_start;
      np = diskfs_make_node (dn);
      np->cache_id = id + 1;	/* see above for rationale for increment */
      mutex_lock (&np->lock);
      c->np = np;
      spin_unlock (&diskfs_node_refcnt_lock);
      
      err = read_disknode (np, node_cache[id].dr, &rr);
      if (!err)
	*npp = np;

      release_rrip (&rr);

      return err;
    }

  
  np->references++;
  spin_unlock (&diskfs_node_refcnt_lock);
  mutex_lock (&np->lock);
  *npp = np;
  return 0;
}


/* Return Epoch-based time from a seven byte according to 9.1.5 */
char *
isodate_915 (char *c, struct timespec *ts)
{
  struct tm tm;
  signed char tz;

  /* Copy into a struct TM. */
  tm.tm_year = *c++;
  tm.tm_mon = *c++ - 1;
  tm.tm_mday = *c++;
  tm.tm_hour = *c++;
  tm.tm_min = *c++;
  tm.tm_sec = *c++;
  tz = *c++;

  tm.tm_isdst = 0;
  ts->tv_sec = timegm (&tm);
  ts->tv_nsec = 0;
  
  /* Only honor TZ offset if it makes sense */
  if (-48 <= tz && tz <= 52)
    ts->tv_sec -= 15 * 60 * tz;	/* TZ is in fifteen minute chunks */

  return c;
}

/* Return Epoch-based time from a seventeen byte according to 8.4.26.1 */
char *
isodate_84261 (char *c, struct timespec *ts)
{
  struct tm tm;
  int hsec;
  signed char tz;

  sscanf (c, "%4d%2d%2d%2d%2d%2d%2d", 
	  &tm.tm_year, &tm.tm_mon, &tm.tm_mday,
	  &tm.tm_hour, &tm.tm_min, &tm.tm_sec,
	  &hsec);

  /* Convert to appropriate units */
  ts->tv_nsec = hsec * 10000000;
  tm.tm_year -= 1900;
  tm.tm_mon--;
  
  tm.tm_isdst = 0;
  ts->tv_sec = timegm (&tm);
  
  tz = c[16];

  /* Only honor TZ offset if it makes sense */
  if (-48 <= tz && tz <= 52)
    ts->tv_sec -= 15 * 60 * tz;	/* TZ is in fifteen minute chunks */

  return c + 17;
}

/* Calculate the file start (in store blocks) of the file at RECORD. */
error_t
calculate_file_start (struct dirrect *record, off_t *file_start,
		      struct rrip_lookup *rr)
{
  error_t err;

  if (rr && (rr->valid & VALID_CL))
    {
      *file_start = (void *) rr->realdirent - (void *)disk_image;
      *file_start >>= store->log2_block_size;
    }
  else if (rr && (rr->valid & VALID_PL))
    *file_start = rr->realfilestart;
  else
    {
      err = diskfs_catch_exception ();
      if (err)
	return err;
  
      *file_start = ((isonum_733 (record->extent) + record->ext_attr_len)
		     * (logical_block_size / store->block_size));

      diskfs_end_catch_exception ();
    }
  return 0;
}


/* Load the inode with directory entry RECORD and cached Rock-Rodge info RR
   into NP.  The directory entry is at OFFSET in BLOCK.  */
error_t
load_inode (struct node **npp, struct dirrect *record, 
	    struct rrip_lookup *rr)
{
  error_t err;
  off_t file_start;
  struct disknode *dn;
  struct node *np;
  
  err = calculate_file_start (record, &file_start, rr);
  if (err)
    return err;
  if (rr->valid & VALID_CL)
    record = rr->realdirent;

  spin_lock (&diskfs_node_refcnt_lock);
  
  /* First check the cache */
  inode_cache_find (file_start, npp);
  if (*npp)
    return 0;
  
  /* Create a new node */
  dn = malloc (sizeof (struct disknode));
  dn->fileinfo = 0;
  dn->file_start = file_start;

  np = diskfs_make_node (dn);

  mutex_lock (&np->lock);

  cache_inode (record, np);
  spin_unlock (&diskfs_node_refcnt_lock);
  
  err = read_disknode (np, record, rr);
  *npp = np;
  return err;
}


/* Read stat information from the directory entry at DR and the
   contents of RL. */
static error_t
read_disknode (struct node *np, struct dirrect *dr,
	       struct rrip_lookup *rl)
{
  error_t err;
  struct stat *st = &np->dn_stat;
  
  st->st_fstype = 9660;	/* xxx */
  st->st_fsid = getpid ();
  st->st_ino = np->dn->file_start;
  st->st_gen = 0;
  st->st_rdev = 0;
  
  err = diskfs_catch_exception ();
  if (err)
    return err;

  if (rl->valid & VALID_PX)
    {
      st->st_mode = rl->mode;
      st->st_nlink = rl->nlink;
      st->st_uid = rl->uid;
      st->st_gid = rl->gid;
    }
  else
    {
      /* If there are no periods, it's a directory. */
      if (((rl->valid & VALID_NM) && !index (rl->name, '.'))
	  || (!(rl->valid & VALID_NM) && !memchr (dr->name, '.', dr->namelen)))
	st->st_mode = S_IFDIR | 0777;
      else
	st->st_mode = S_IFREG | 0666;

      st->st_nlink = 1;
      st->st_uid = 0;
      st->st_gid = 0;
    }
  
  st->st_author = st->st_gid;

  st->st_size = isonum_733 (dr->size);

  if ((rl->valid & VALID_PN)
      && (S_ISCHR (st->st_mode) || S_ISBLK (st->st_mode)))
    st->st_rdev = rl->rdev;
  else 
    st->st_rdev = 0;
  
  if (dr->ileave)
    /* XXX ??? */
    st->st_size = 0;
  
  /* Calculate these if we'll need them */
  if (!(rl->valid & VALID_TF)
      || ((rl->tfflags & (TF_CREATION|TF_ACCESS|TF_MODIFY))
	  != (TF_CREATION|TF_ACCESS|TF_MODIFY)))
    {
      struct timespec ts;
      isodate_915 (dr->date, &ts);
      st->st_ctime = st->st_mtime = st->st_atime = ts.tv_sec;
      st->st_ctime_usec = st->st_mtime_usec = st->st_atime_usec 
	= ts.tv_nsec * 1000;
    }
  
  /* Override what we have better info for */
  if (rl->valid & VALID_TF)
    {
      if (rl->tfflags & TF_CREATION)
	{
	  st->st_ctime = rl->ctime.tv_sec;
	  st->st_ctime_usec = rl->ctime.tv_nsec * 1000;
	}
      
      if (rl->tfflags & TF_ACCESS)
	{
	  st->st_atime = rl->atime.tv_sec;
	  st->st_atime_usec = rl->atime.tv_nsec * 1000;
	}
      
      if (rl->tfflags & TF_MODIFY)
	{
	  st->st_mtime = rl->mtime.tv_sec;
	  st->st_mtime_usec = rl->mtime.tv_nsec * 1000;
	}
    }
  
  st->st_blksize = logical_block_size;
  st->st_blocks = (st->st_size - 1) / 512 + 1;
  st->st_flags = 0;
  
  if (S_ISLNK (st->st_mode))
    {
      if (rl->valid & VALID_SL)
	{
	  np->dn->link_target = rl->name;
	  rl->name = 0;
	  st->st_size = strlen (np->dn->link_target);
	}
      else
	{
	  st->st_mode &= ~S_IFMT;
	  st->st_mode |= S_IFREG;
	}
    }

  diskfs_end_catch_exception ();
  
  return 0;
}

/* Symlink targets are never stored in files, so always use this. */
static error_t
read_symlink_hook (struct node *np, char *buf)
{
  bcopy (np->dn->link_target, buf, np->dn_stat.st_size);
  return 0;
}
error_t (*diskfs_read_symlink_hook) (struct node *, char *) 
     = read_symlink_hook;


/* The last reference to NP has gone away; drop it from the cache
   and clean all state in the dn structure. */
void
diskfs_node_norefs (struct node *np)
{
  assert (node_cache[np->cache_id - 1].np == np);
  node_cache[np->cache_id - 1].np = 0;

  assert (!np->dn->fileinfo);
  free (np->dn);
  free (np);
}

/* The last hard reference to a node has gone away; arrange to have
   all the weak references dropped that can be.  */
void
diskfs_try_dropping_softrefs (struct node *np)
{
  drop_pager_softrefs (np);
}

void
diskfs_lost_hardrefs (struct node *np)
{
}

void
diskfs_new_hardrefs (struct node *np)
{
  allow_pager_softrefs (np);
}

error_t
diskfs_truncate (struct node *np, off_t length)
{
  return EROFS;
}

error_t
diskfs_grow (struct node *np, off_t end, struct protid *cred)
{
  return EROFS;
}

error_t
diskfs_set_translator (struct node *np, char *name, u_int namelen, 
		       struct protid *cred)
{
  return EROFS;
}

error_t
diskfs_get_translator (struct node *np, char **namep, u_int *namelen)
{
  return EOPNOTSUPP;
}

void
diskfs_shutdown_soft_ports ()
{
    /* Should initiate termination of internally held pager ports
     (the only things that should be soft) XXX */
}

error_t
diskfs_node_reload (struct node *node)
{
  /* Never necessary on a read-only medium */
  return 0;
}

error_t
diskfs_validate_author_change (struct node *np, uid_t author)
{
  return EROFS;
}

error_t
diskfs_node_iterate (error_t (*fun)(struct node *))
{
  /* We never actually have to do anything, because this function
     is only used for things that have to do with read-write media. */
  return 0;
}

void
diskfs_write_disknode (struct node *np, int wait)
{
}

error_t
diskfs_set_statfs (struct statfs *st)
{
  /* XXX return something useful */
  bzero (st, sizeof *st);
  return 0;
}

error_t
diskfs_S_file_get_storage_info (struct protid *cred,
				mach_port_t **ports,
				mach_msg_type_name_t *ports_type,
				mach_msg_type_number_t *num_ports,
				int **ints, mach_msg_type_number_t *num_ints,
				off_t **offsets,
				mach_msg_type_number_t *num_offsets,
				char **data, mach_msg_type_number_t *data_len)
{
  /* XXX */
  return EOPNOTSUPP;
}

void
diskfs_free_node (struct node *no, mode_t mode)
{
  abort ();
}

error_t
diskfs_alloc_node (struct node *dp, mode_t mode, struct node **np)
{
  return EROFS;
}