module/zfs/pathname.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or https://opensource.org/licenses/CDDL-1.0.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21 /*
  22  * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
  23  * Use is subject to license terms.
  24  */
  25
  26 /*      Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T     */
  27 /*        All Rights Reserved   */
  28
  29 /*
  30  * University Copyright- Copyright (c) 1982, 1986, 1988
  31  * The Regents of the University of California
  32  * All Rights Reserved
  33  *
  34  * University Acknowledgment- Portions of this document are derived from
  35  * software developed by the University of California, Berkeley, and its
  36  * contributors.
  37  */
  38
  39
  40 #include <sys/types.h>
  41 #include <sys/pathname.h>
  42 #include <sys/kmem.h>
  43 #include <sys/sysmacros.h>
  44
  45 /*
  46  * Pathname utilities.
  47  *
  48  * In translating file names we copy each argument file
  49  * name into a pathname structure where we operate on it.
  50  * Each pathname structure can hold "pn_bufsize" characters
  51  * including a terminating null, and operations here support
  52  * allocating and freeing pathname structures, fetching
  53  * strings from user space, getting the next character from
  54  * a pathname, combining two pathnames (used in symbolic
  55  * link processing), and peeling off the first component
  56  * of a pathname.
  57  */
  58
  59 /*
  60  * Allocate contents of pathname structure.  Structure is typically
  61  * an automatic variable in calling routine for convenience.
  62  *
  63  * May sleep in the call to kmem_alloc() and so must not be called
  64  * from interrupt level.
  65  */
  66 void
  67 pn_alloc(struct pathname *pnp)
  68 {
  69         pn_alloc_sz(pnp, MAXPATHLEN);
  70 }
  71 void
  72 pn_alloc_sz(struct pathname *pnp, size_t sz)
  73 {
  74         pnp->pn_buf = kmem_alloc(sz, KM_SLEEP);
  75         pnp->pn_bufsize = sz;
  76 }
  77
  78 /*
  79  * Free pathname resources.
  80  */
  81 void
  82 pn_free(struct pathname *pnp)
  83 {
  84         /* pn_bufsize is usually MAXPATHLEN, but may not be */
  85         kmem_free(pnp->pn_buf, pnp->pn_bufsize);
  86         pnp->pn_buf = NULL;
  87         pnp->pn_bufsize = 0;
  88 }