151 lines
3.6 KiB
C
151 lines
3.6 KiB
C
/* $NetBSD: vfs_cwd.c,v 1.1 2008/11/18 11:36:58 pooka Exp $ */
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/*-
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* Copyright (c) 2008 The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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* Current working directory.
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: vfs_cwd.c,v 1.1 2008/11/18 11:36:58 pooka Exp $");
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#include <sys/param.h>
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#include <sys/atomic.h>
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#include <sys/filedesc.h>
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#include <sys/proc.h>
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#include <sys/vnode.h>
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static int cwdi_ctor(void *, void *, int);
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static void cwdi_dtor(void *, void *);
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static pool_cache_t cwdi_cache;
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void
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cwd_sys_init(void)
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{
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cwdi_cache = pool_cache_init(sizeof(struct cwdinfo), coherency_unit,
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0, 0, "cwdi", NULL, IPL_NONE, cwdi_ctor, cwdi_dtor, NULL);
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KASSERT(cwdi_cache != NULL);
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}
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/*
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* Create an initial cwdinfo structure, using the same current and root
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* directories as curproc.
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*/
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struct cwdinfo *
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cwdinit(void)
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{
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struct cwdinfo *cwdi;
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struct cwdinfo *copy;
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cwdi = pool_cache_get(cwdi_cache, PR_WAITOK);
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copy = curproc->p_cwdi;
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rw_enter(©->cwdi_lock, RW_READER);
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cwdi->cwdi_cdir = copy->cwdi_cdir;
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if (cwdi->cwdi_cdir)
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VREF(cwdi->cwdi_cdir);
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cwdi->cwdi_rdir = copy->cwdi_rdir;
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if (cwdi->cwdi_rdir)
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VREF(cwdi->cwdi_rdir);
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cwdi->cwdi_edir = copy->cwdi_edir;
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if (cwdi->cwdi_edir)
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VREF(cwdi->cwdi_edir);
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cwdi->cwdi_cmask = copy->cwdi_cmask;
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cwdi->cwdi_refcnt = 1;
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rw_exit(©->cwdi_lock);
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return (cwdi);
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}
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static int
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cwdi_ctor(void *arg, void *obj, int flags)
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{
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struct cwdinfo *cwdi = obj;
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rw_init(&cwdi->cwdi_lock);
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return 0;
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}
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static void
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cwdi_dtor(void *arg, void *obj)
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{
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struct cwdinfo *cwdi = obj;
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rw_destroy(&cwdi->cwdi_lock);
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}
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/*
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* Make p2 share p1's cwdinfo.
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*/
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void
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cwdshare(struct proc *p2)
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{
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struct cwdinfo *cwdi;
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cwdi = curproc->p_cwdi;
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atomic_inc_uint(&cwdi->cwdi_refcnt);
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p2->p_cwdi = cwdi;
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}
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/*
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* Make sure proc has only one reference to its cwdi, creating
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* a new one if necessary.
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*/
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void
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cwdunshare(struct proc *p)
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{
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struct cwdinfo *cwdi = p->p_cwdi;
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if (cwdi->cwdi_refcnt > 1) {
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cwdi = cwdinit();
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cwdfree(p->p_cwdi);
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p->p_cwdi = cwdi;
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}
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}
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/*
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* Release a cwdinfo structure.
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*/
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void
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cwdfree(struct cwdinfo *cwdi)
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{
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if (atomic_dec_uint_nv(&cwdi->cwdi_refcnt) > 0)
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return;
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vrele(cwdi->cwdi_cdir);
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if (cwdi->cwdi_rdir)
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vrele(cwdi->cwdi_rdir);
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if (cwdi->cwdi_edir)
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vrele(cwdi->cwdi_edir);
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pool_cache_put(cwdi_cache, cwdi);
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}
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