text: /*	$NetBSD: rawfs.c,v 1.1 1997/02/04 03:52:46 thorpej Exp $	*/
  
  /*
   * Copyright (c) 1995 Gordon W. Ross
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   * 3. The name of the author may not be used to endorse or promote products
   *    derived from this software without specific prior written permission.
   * 4. All advertising materials mentioning features or use of this software
   *    must display the following acknowledgement:
   *      This product includes software developed by Gordon W. Ross
   *
   * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
   * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
   * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
   * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
   * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
   * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
   * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   */
  
  /*
   * Raw file system - for stream devices like tapes.
   * No random access, only sequential read allowed.
   * This exists only to allow upper level code to be
   * shielded from the fact that the device must be
   * read only with whole block position and size.
   */
  
  #include <sys/param.h>
  
  #include <lib/libsa/stand.h>
  #include <hp300/stand/common/rawfs.h>
  
  extern int debug;
  
  /* Our devices are generally willing to do 8K transfers. */
  #define	RAWFS_BSIZE	0x2000
  
  /*
   * In-core open file.
   */
  struct rawfs_file {
  	daddr_t		fs_nextblk;	/* block number to read next */
  	int		fs_len;		/* amount left in f_buf */
  	char *		fs_ptr;		/* read pointer into f_buf */
  	char		fs_buf[RAWFS_BSIZE];
  };
  
  static int
  rawfs_get_block __P((struct open_file *));
  
  int
  rawfs_open(path, f)
  	char *path;
  	struct open_file *f;
  {
  	struct rawfs_file *fs;
  
  	/*
  	 * The actual tape driver has already been opened.
  	 * Just allocate the I/O buffer, etc.
  	 */
  	fs = alloc(sizeof(struct rawfs_file));
  	fs->fs_nextblk = 0;
  	fs->fs_len = 0;
  	fs->fs_ptr = fs->fs_buf;
  
  #ifdef	DEBUG_RAWFS
  	printf("rawfs_open: fs=0x%x\n", (u_long)fs);
  #endif
  
  	f->f_fsdata = fs;
  	return (0);
  }
  
  int
  rawfs_close(f)
  	struct open_file *f;
  {
  	struct rawfs_file *fs;
  
  	fs = (struct rawfs_file *) f->f_fsdata;
  	f->f_fsdata = (void *)0;
  
  #ifdef	DEBUG_RAWFS
  	printf("rawfs_close: fs=0x%x\n", (u_long)fs);
  #endif
  
  	if (fs != (struct rawfs_file *)0)
  		free(fs, sizeof(*fs));
  
  	return (0);
  }
  
  int
  rawfs_read(f, start, size, resid)
  	struct open_file *f;
  	void *start;
  	u_int size;
  	u_int *resid;
  {
  	struct rawfs_file *fs = (struct rawfs_file *)f->f_fsdata;
  	char *addr = start;
  	int error = 0;
  	size_t csize;
  
  #ifdef DEBUG_RAWFS
  	printf("rawfs_read: file=0x%x, start=0x%x, size=%d, resid=0x%x\n",
  	    (u_long)f, (u_long)start, size, resid);
  	printf("            fs=0x%x\n", (u_long)fs);
  #endif
  
  	while (size != 0) {
  
  		if (fs->fs_len == 0)
  			if ((error = rawfs_get_block(f)) != 0)
  				break;
  
  		if (fs->fs_len <= 0)
  			break;	/* EOF */
  
  		csize = size;
  		if (csize > fs->fs_len)
  			csize = fs->fs_len;
  
  		bcopy(fs->fs_ptr, addr, csize);
  		fs->fs_ptr += csize;
  		fs->fs_len -= csize;
  		addr += csize;
  		size -= csize;
  	}
  	if (resid)
  		*resid = size;
  	return (error);
  }
  
  int
  rawfs_write(f, start, size, resid)
  	struct open_file *f;
  	void *start;
  	size_t size;
  	size_t *resid;	/* out */
  {
  #ifdef	DEBUG_RAWFS
  	printf("rawfs_write: YOU'RE NOT SUPPOSED TO GET HERE!\n");
  #endif
  	return (EROFS);
  }
  
  off_t
  rawfs_seek(f, offset, where)
  	struct open_file *f;
  	off_t offset;
  	int where;
  {
  #ifdef	DEBUG_RAWFS
  	printf("rawfs_seek: YOU'RE NOT SUPPOSED TO GET HERE!\n");
  #endif
  	return (EFTYPE);
  }
  
  int
  rawfs_stat(f, sb)
  	struct open_file *f;
  	struct stat *sb;
  {
  #ifdef	DEBUG_RAWFS
  	printf("rawfs_stat: I'll let you live only because of exec.c\n");
  #endif
  	/*
  	 * Clear out the stat buffer so that the uid check
  	 * won't fail.  See sys/lib/libsa/exec.c
  	 */
  	bzero(sb, sizeof(*sb));
  
  	return (EFTYPE);
  }
  
  /*
   * Read a block from the underlying stream device
   * (In our case, a tape drive.)
   */
  static int
  rawfs_get_block(f)
  	struct open_file *f;
  {
  	struct rawfs_file *fs;
  	int error, len;
  
  	fs = (struct rawfs_file *)f->f_fsdata;
  	fs->fs_ptr = fs->fs_buf;
  
  	twiddle();
  #ifdef DEBUG_RAWFS
  	printf("rawfs_get_block: calling strategy\n");
  #endif
  	error = f->f_dev->dv_strategy(f->f_devdata, F_READ,
  		fs->fs_nextblk, RAWFS_BSIZE, fs->fs_buf, &len);
  #ifdef DEBUG_RAWFS
  	printf("rawfs_get_block: strategy returned %d\n", error);
  #endif
  
  	if (!error) {
  		fs->fs_len = len;
  		fs->fs_nextblk += (RAWFS_BSIZE / DEV_BSIZE);
  	}
  
  	return (error);
  }
  