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File: [cvs.NetBSD.org] / src / sys / kern / vfs_cwd.c (download)

Revision 1.4, Tue Feb 15 15:54:28 2011 UTC (13 years, 2 months ago) by pooka
Branch: MAIN
CVS Tags: yamt-pagecache-tag8, yamt-pagecache-base9, yamt-pagecache-base8, yamt-pagecache-base7, yamt-pagecache-base6, yamt-pagecache-base5, yamt-pagecache-base4, yamt-pagecache-base3, yamt-pagecache-base2, yamt-pagecache-base, yamt-pagecache, tls-maxphys-base-20171202, tls-maxphys-base, tls-maxphys, tls-earlyentropy-base, tls-earlyentropy, rmind-uvmplock-nbase, rmind-uvmplock-base, rmind-smpnet-nbase, rmind-smpnet-base, rmind-smpnet, riastradh-xf86-video-intel-2-7-1-pre-2-21-15, riastradh-drm2-base3, riastradh-drm2-base2, riastradh-drm2-base1, riastradh-drm2-base, riastradh-drm2, prg-localcount2-base3, prg-localcount2-base2, prg-localcount2-base1, prg-localcount2-base, prg-localcount2, phil-wifi-base, phil-wifi-20191119, phil-wifi-20190609, pgoyette-localcount-base, pgoyette-localcount-20170426, pgoyette-localcount-20170320, pgoyette-localcount-20170107, pgoyette-localcount-20161104, pgoyette-localcount-20160806, pgoyette-localcount-20160726, pgoyette-localcount, pgoyette-compat-merge-20190127, pgoyette-compat-base, pgoyette-compat-20190127, pgoyette-compat-20190118, pgoyette-compat-1226, pgoyette-compat-1126, pgoyette-compat-1020, pgoyette-compat-0930, pgoyette-compat-0906, pgoyette-compat-0728, pgoyette-compat-0625, pgoyette-compat-0521, pgoyette-compat-0502, pgoyette-compat-0422, pgoyette-compat-0415, pgoyette-compat-0407, pgoyette-compat-0330, pgoyette-compat-0322, pgoyette-compat-0315, pgoyette-compat, perseant-stdc-iso10646-base, perseant-stdc-iso10646, nick-nhusb-base-20170825, nick-nhusb-base-20170204, nick-nhusb-base-20161204, nick-nhusb-base-20161004, nick-nhusb-base-20160907, nick-nhusb-base-20160529, nick-nhusb-base-20160422, nick-nhusb-base-20160319, nick-nhusb-base-20151226, nick-nhusb-base-20150921, nick-nhusb-base-20150606, nick-nhusb-base-20150406, nick-nhusb-base, nick-nhusb, netbsd-9-base, netbsd-9-3-RELEASE, netbsd-9-2-RELEASE, netbsd-9-1-RELEASE, netbsd-9-0-RELEASE, netbsd-9-0-RC2, netbsd-9-0-RC1, netbsd-9, netbsd-8-base, netbsd-8-2-RELEASE, netbsd-8-1-RELEASE, netbsd-8-1-RC1, netbsd-8-0-RELEASE, netbsd-8-0-RC2, netbsd-8-0-RC1, netbsd-8, netbsd-7-nhusb-base-20170116, netbsd-7-nhusb-base, netbsd-7-nhusb, netbsd-7-base, netbsd-7-2-RELEASE, netbsd-7-1-RELEASE, netbsd-7-1-RC2, netbsd-7-1-RC1, netbsd-7-1-2-RELEASE, netbsd-7-1-1-RELEASE, netbsd-7-1, netbsd-7-0-RELEASE, netbsd-7-0-RC3, netbsd-7-0-RC2, netbsd-7-0-RC1, netbsd-7-0-2-RELEASE, netbsd-7-0-1-RELEASE, netbsd-7-0, netbsd-7, netbsd-6-base, netbsd-6-1-RELEASE, netbsd-6-1-RC4, netbsd-6-1-RC3, netbsd-6-1-RC2, netbsd-6-1-RC1, netbsd-6-1-5-RELEASE, netbsd-6-1-4-RELEASE, netbsd-6-1-3-RELEASE, netbsd-6-1-2-RELEASE, netbsd-6-1-1-RELEASE, netbsd-6-1, netbsd-6-0-RELEASE, netbsd-6-0-RC2, netbsd-6-0-RC1, netbsd-6-0-6-RELEASE, netbsd-6-0-5-RELEASE, netbsd-6-0-4-RELEASE, netbsd-6-0-3-RELEASE, netbsd-6-0-2-RELEASE, netbsd-6-0-1-RELEASE, netbsd-6-0, netbsd-6, matt-nb8-mediatek-base, matt-nb8-mediatek, matt-nb6-plus-nbase, matt-nb6-plus-base, matt-nb6-plus, localcount-20160914, khorben-n900, jmcneill-usbmp-pre-base2, jmcneill-usbmp-base9, jmcneill-usbmp-base8, jmcneill-usbmp-base7, jmcneill-usbmp-base6, jmcneill-usbmp-base5, jmcneill-usbmp-base4, jmcneill-usbmp-base3, jmcneill-usbmp-base2, jmcneill-usbmp-base10, jmcneill-usbmp-base, jmcneill-usbmp, jmcneill-audiomp3-base, jmcneill-audiomp3, jdolecek-ncq-base, jdolecek-ncq, isaki-audio2-base, isaki-audio2, cherry-xenmp-base, cherry-xenmp, bouyer-socketcan-base1, bouyer-socketcan-base, bouyer-socketcan, bouyer-quota2-nbase, bouyer-quota2-base, agc-symver-base, agc-symver, ad-namecache-base2, ad-namecache-base1, ad-namecache-base
Branch point for: phil-wifi, ad-namecache
Changes since 1.3: +13 -2 lines 

Support FD_CLOEXEC in rump kernels.

/*	$NetBSD: vfs_cwd.c,v 1.4 2011/02/15 15:54:28 pooka Exp $	*/

/*-
 * Copyright (c) 2008 The NetBSD Foundation, Inc.
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``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 FOUNDATION OR CONTRIBUTORS
 * 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.
 */

/*
 * Current working directory.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: vfs_cwd.c,v 1.4 2011/02/15 15:54:28 pooka Exp $");

#include <sys/param.h>
#include <sys/atomic.h>
#include <sys/filedesc.h>
#include <sys/proc.h>
#include <sys/vnode.h>

static int	cwdi_ctor(void *, void *, int);
static void	cwdi_dtor(void *, void *);

static pool_cache_t cwdi_cache;

void
cwd_sys_init(void)
{

	cwdi_cache = pool_cache_init(sizeof(struct cwdinfo), coherency_unit,
	    0, 0, "cwdi", NULL, IPL_NONE, cwdi_ctor, cwdi_dtor, NULL);
	KASSERT(cwdi_cache != NULL);
}

/*
 * Create an initial cwdinfo structure, using the same current and root
 * directories as curproc.
 */
struct cwdinfo *
cwdinit(void)
{
	struct cwdinfo *cwdi;
	struct cwdinfo *copy;

	cwdi = pool_cache_get(cwdi_cache, PR_WAITOK);
	copy = curproc->p_cwdi;

	rw_enter(&copy->cwdi_lock, RW_READER);
	cwdi->cwdi_cdir = copy->cwdi_cdir;
	if (cwdi->cwdi_cdir)
		vref(cwdi->cwdi_cdir);
	cwdi->cwdi_rdir = copy->cwdi_rdir;
	if (cwdi->cwdi_rdir)
		vref(cwdi->cwdi_rdir);
	cwdi->cwdi_edir = copy->cwdi_edir;
	if (cwdi->cwdi_edir)
		vref(cwdi->cwdi_edir);
	cwdi->cwdi_cmask = copy->cwdi_cmask;
	cwdi->cwdi_refcnt = 1;
	rw_exit(&copy->cwdi_lock);

	return (cwdi);
}

static int
cwdi_ctor(void *arg, void *obj, int flags)
{
	struct cwdinfo *cwdi = obj;

	rw_init(&cwdi->cwdi_lock);

	return 0;
}

static void
cwdi_dtor(void *arg, void *obj)
{
	struct cwdinfo *cwdi = obj;

	rw_destroy(&cwdi->cwdi_lock);
}

/*
 * Make p2 share p1's cwdinfo.
 */
void
cwdshare(struct proc *p2)
{
	struct cwdinfo *cwdi;

	cwdi = curproc->p_cwdi;

	atomic_inc_uint(&cwdi->cwdi_refcnt);
	p2->p_cwdi = cwdi;
}

/*
 * Make sure proc has only one reference to its cwdi, creating
 * a new one if necessary.
 */
void
cwdunshare(struct proc *p)
{
	struct cwdinfo *cwdi = p->p_cwdi;

	if (cwdi->cwdi_refcnt > 1) {
		cwdi = cwdinit();
		cwdfree(p->p_cwdi);
		p->p_cwdi = cwdi;
	}
}

/*
 * Release a cwdinfo structure.
 */
void
cwdfree(struct cwdinfo *cwdi)
{

	if (atomic_dec_uint_nv(&cwdi->cwdi_refcnt) > 0)
		return;

	vrele(cwdi->cwdi_cdir);
	if (cwdi->cwdi_rdir)
		vrele(cwdi->cwdi_rdir);
	if (cwdi->cwdi_edir)
		vrele(cwdi->cwdi_edir);
	pool_cache_put(cwdi_cache, cwdi);
}

void
cwdexec(struct proc *p)
{

	cwdunshare(p);

	if (p->p_cwdi->cwdi_edir) {
		vrele(p->p_cwdi->cwdi_edir);
	}
}