143 lines
4.2 KiB
C
143 lines
4.2 KiB
C
/* $NetBSD: kern_uidinfo.c,v 1.5 2009/03/22 00:49:13 ad Exp $ */
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/*-
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* Copyright (c) 1982, 1986, 1991, 1993
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* The Regents of the University of California. All rights reserved.
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* (c) UNIX System Laboratories, Inc.
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* All or some portions of this file are derived from material licensed
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* to the University of California by American Telephone and Telegraph
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* Co. or Unix System Laboratories, Inc. and are reproduced herein with
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* the permission of UNIX System Laboratories, Inc.
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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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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: kern_uidinfo.c,v 1.5 2009/03/22 00:49:13 ad Exp $");
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/kmem.h>
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#include <sys/proc.h>
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#include <sys/atomic.h>
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#include <sys/uidinfo.h>
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#include <sys/cpu.h>
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static SLIST_HEAD(uihashhead, uidinfo) *uihashtbl;
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static u_long uihash;
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#define UIHASH(uid) (&uihashtbl[(uid) & uihash])
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void
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uid_init(void)
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{
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/*
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* In case of MP system, SLIST_FOREACH would force a cache line
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* write-back for every modified 'uidinfo', thus we try to keep the
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* lists short.
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*/
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const u_int uihash_sz = (maxcpus > 1 ? 1024 : 64);
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uihashtbl = hashinit(uihash_sz, HASH_SLIST, true, &uihash);
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/*
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* Ensure that uid 0 is always in the user hash table, as
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* sbreserve() expects it available from interrupt context.
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*/
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(void)uid_find(0);
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}
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struct uidinfo *
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uid_find(uid_t uid)
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{
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struct uidinfo *uip, *uip_first, *newuip;
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struct uihashhead *uipp;
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uipp = UIHASH(uid);
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newuip = NULL;
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/*
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* To make insertion atomic, abstraction of SLIST will be violated.
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*/
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uip_first = uipp->slh_first;
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again:
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SLIST_FOREACH(uip, uipp, ui_hash) {
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if (uip->ui_uid != uid)
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continue;
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if (newuip != NULL)
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kmem_free(newuip, sizeof(*newuip));
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return uip;
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}
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if (newuip == NULL)
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newuip = kmem_zalloc(sizeof(*newuip), KM_SLEEP);
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newuip->ui_uid = uid;
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/*
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* If atomic insert is unsuccessful, another thread might be
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* allocated this 'uid', thus full re-check is needed.
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*/
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newuip->ui_hash.sle_next = uip_first;
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membar_producer();
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uip = atomic_cas_ptr(&uipp->slh_first, uip_first, newuip);
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if (uip != uip_first) {
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uip_first = uip;
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goto again;
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}
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return newuip;
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}
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/*
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* Change the count associated with number of processes
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* a given user is using.
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*/
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int
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chgproccnt(uid_t uid, int diff)
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{
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struct uidinfo *uip;
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long proccnt;
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uip = uid_find(uid);
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proccnt = atomic_add_long_nv(&uip->ui_proccnt, diff);
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KASSERT(proccnt >= 0);
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return proccnt;
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}
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int
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chgsbsize(struct uidinfo *uip, u_long *hiwat, u_long to, rlim_t xmax)
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{
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rlim_t nsb;
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const long diff = to - *hiwat;
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nsb = (rlim_t)atomic_add_long_nv((long *)&uip->ui_sbsize, diff);
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if (diff > 0 && nsb > xmax) {
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atomic_add_long((long *)&uip->ui_sbsize, -diff);
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return 0;
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}
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*hiwat = to;
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return 1;
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}
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