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freebsd-skq/sys/kern/kern_resource.c
davidxu 4b9b549ca2 Move UPCALL related data structure out of kse, introduce a new 
data structure called kse_upcall to manage UPCALL. All KSE binding
and loaning code are gone.

A thread owns an upcall can collect all completed syscall contexts in
its ksegrp, turn itself into UPCALL mode, and takes those contexts back
to userland. Any thread without upcall structure has to export their
contexts and exit at user boundary.

Any thread running in user mode owns an upcall structure, when it enters
kernel, if the kse mailbox's current thread pointer is not NULL, then
when the thread is blocked in kernel, a new UPCALL thread is created and
the upcall structure is transfered to the new UPCALL thread. if the kse
mailbox's current thread pointer is NULL, then when a thread is blocked
in kernel, no UPCALL thread will be created.

Each upcall always has an owner thread. Userland can remove an upcall by
calling kse_exit, when all upcalls in ksegrp are removed, the group is
atomatically shutdown. An upcall owner thread also exits when process is
in exiting state. when an owner thread exits, the upcall it owns is also
removed.

KSE is a pure scheduler entity. it represents a virtual cpu. when a thread
is running, it always has a KSE associated with it. scheduler is free to
assign a KSE to thread according thread priority, if thread priority is changed,
KSE can be moved from one thread to another.

When a ksegrp is created, there is always N KSEs created in the group. the
N is the number of physical cpu in the current system. This makes it is
possible that even an userland UTS is single CPU safe, threads in kernel still
can execute on different cpu in parallel. Userland calls kse_create to add more
upcall structures into ksegrp to increase concurrent in userland itself, kernel
is not restricted by number of upcalls userland provides.

The code hasn't been tested under SMP by author due to lack of hardware.

Reviewed by: julian
2003-01-26 11:41:35 +00:00

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/*-
* Copyright (c) 1982, 1986, 1991, 1993
* The Regents of the University of California. All rights reserved.
* (c) UNIX System Laboratories, Inc.
* All or some portions of this file are derived from material licensed
* to the University of California by American Telephone and Telegraph
* Co. or Unix System Laboratories, Inc. and are reproduced herein with
* the permission of UNIX System Laboratories, Inc.
*
* 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
*
* @(#)kern_resource.c 8.5 (Berkeley) 1/21/94
* $FreeBSD$
*/
#include "opt_compat.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/sysproto.h>
#include <sys/file.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/resourcevar.h>
#include <sys/sched.h>
#include <sys/sx.h>
#include <sys/sysent.h>
#include <sys/time.h>
#include <vm/vm.h>
#include <vm/vm_param.h>
#include <vm/pmap.h>
#include <vm/vm_map.h>
static int donice(struct thread *td, struct proc *chgp, int n);
static MALLOC_DEFINE(M_UIDINFO, "uidinfo", "uidinfo structures");
#define UIHASH(uid) (&uihashtbl[(uid) & uihash])
static struct mtx uihashtbl_mtx;
static LIST_HEAD(uihashhead, uidinfo) *uihashtbl;
static u_long uihash; /* size of hash table - 1 */
static struct uidinfo *uilookup(uid_t uid);
/*
* Resource controls and accounting.
*/
#ifndef _SYS_SYSPROTO_H_
struct getpriority_args {
int which;
int who;
};
#endif
/*
* MPSAFE
*/
int
getpriority(td, uap)
struct thread *td;
register struct getpriority_args *uap;
{
struct proc *p;
int low = PRIO_MAX + 1;
int error = 0;
struct ksegrp *kg;
mtx_lock(&Giant);
switch (uap->which) {
case PRIO_PROCESS:
if (uap->who == 0)
low = td->td_ksegrp->kg_nice;
else {
p = pfind(uap->who);
if (p == NULL)
break;
if (p_cansee(td, p) == 0) {
FOREACH_KSEGRP_IN_PROC(p, kg) {
if (kg->kg_nice < low)
low = kg->kg_nice;
}
}
PROC_UNLOCK(p);
}
break;
case PRIO_PGRP: {
register struct pgrp *pg;
sx_slock(&proctree_lock);
if (uap->who == 0) {
pg = td->td_proc->p_pgrp;
PGRP_LOCK(pg);
} else {
pg = pgfind(uap->who);
if (pg == NULL) {
sx_sunlock(&proctree_lock);
break;
}
}
sx_sunlock(&proctree_lock);
LIST_FOREACH(p, &pg->pg_members, p_pglist) {
PROC_LOCK(p);
if (!p_cansee(td, p)) {
FOREACH_KSEGRP_IN_PROC(p, kg) {
if (kg->kg_nice < low)
low = kg->kg_nice;
}
}
PROC_UNLOCK(p);
}
PGRP_UNLOCK(pg);
break;
}
case PRIO_USER:
if (uap->who == 0)
uap->who = td->td_ucred->cr_uid;
sx_slock(&allproc_lock);
LIST_FOREACH(p, &allproc, p_list) {
PROC_LOCK(p);
if (!p_cansee(td, p) &&
p->p_ucred->cr_uid == uap->who) {
FOREACH_KSEGRP_IN_PROC(p, kg) {
if (kg->kg_nice < low)
low = kg->kg_nice;
}
}
PROC_UNLOCK(p);
}
sx_sunlock(&allproc_lock);
break;
default:
error = EINVAL;
break;
}
if (low == PRIO_MAX + 1 && error == 0)
error = ESRCH;
td->td_retval[0] = low;
mtx_unlock(&Giant);
return (error);
}
#ifndef _SYS_SYSPROTO_H_
struct setpriority_args {
int which;
int who;
int prio;
};
#endif
/*
* MPSAFE
*/
/* ARGSUSED */
int
setpriority(td, uap)
struct thread *td;
register struct setpriority_args *uap;
{
struct proc *curp = td->td_proc;
register struct proc *p;
int found = 0, error = 0;
mtx_lock(&Giant);
switch (uap->which) {
case PRIO_PROCESS:
if (uap->who == 0) {
PROC_LOCK(curp);
error = donice(td, curp, uap->prio);
PROC_UNLOCK(curp);
} else {
p = pfind(uap->who);
if (p == 0)
break;
if (p_cansee(td, p) == 0)
error = donice(td, p, uap->prio);
PROC_UNLOCK(p);
}
found++;
break;
case PRIO_PGRP: {
register struct pgrp *pg;
sx_slock(&proctree_lock);
if (uap->who == 0) {
pg = curp->p_pgrp;
PGRP_LOCK(pg);
} else {
pg = pgfind(uap->who);
if (pg == NULL) {
sx_sunlock(&proctree_lock);
break;
}
}
sx_sunlock(&proctree_lock);
LIST_FOREACH(p, &pg->pg_members, p_pglist) {
PROC_LOCK(p);
if (!p_cansee(td, p)) {
error = donice(td, p, uap->prio);
found++;
}
PROC_UNLOCK(p);
}
PGRP_UNLOCK(pg);
break;
}
case PRIO_USER:
if (uap->who == 0)
uap->who = td->td_ucred->cr_uid;
sx_slock(&allproc_lock);
FOREACH_PROC_IN_SYSTEM(p) {
PROC_LOCK(p);
if (p->p_ucred->cr_uid == uap->who &&
!p_cansee(td, p)) {
error = donice(td, p, uap->prio);
found++;
}
PROC_UNLOCK(p);
}
sx_sunlock(&allproc_lock);
break;
default:
error = EINVAL;
break;
}
if (found == 0 && error == 0)
error = ESRCH;
mtx_unlock(&Giant);
return (error);
}
/*
* Set "nice" for a process. Doesn't really understand threaded processes well
* but does try. Has the unfortunate side effect of making all the NICE
* values for a process's ksegrps the same.. This suggests that
* NICE valuse should be stored as a process nice and deltas for the ksegrps.
* (but not yet).
*/
static int
donice(struct thread *td, struct proc *p, int n)
{
int error;
int low = PRIO_MAX + 1;
struct ksegrp *kg;
PROC_LOCK_ASSERT(p, MA_OWNED);
if ((error = p_cansched(td, p)))
return (error);
if (n > PRIO_MAX)
n = PRIO_MAX;
if (n < PRIO_MIN)
n = PRIO_MIN;
/*
* Only allow nicing if to more than the lowest nice.
* e.g. nices of 4,3,2 allow nice to 3 but not 1
*/
FOREACH_KSEGRP_IN_PROC(p, kg) {
if (kg->kg_nice < low)
low = kg->kg_nice;
}
if (n < low && suser(td))
return (EACCES);
FOREACH_KSEGRP_IN_PROC(p, kg) {
sched_nice(kg, n);
}
return (0);
}
/* rtprio system call */
#ifndef _SYS_SYSPROTO_H_
struct rtprio_args {
int function;
pid_t pid;
struct rtprio *rtp;
};
#endif
/*
* Set realtime priority
*/
/*
* MPSAFE
*/
/* ARGSUSED */
int
rtprio(td, uap)
struct thread *td;
register struct rtprio_args *uap;
{
struct proc *curp = td->td_proc;
register struct proc *p;
struct rtprio rtp;
int error, cierror = 0;
/* Perform copyin before acquiring locks if needed. */
if (uap->function == RTP_SET)
cierror = copyin(uap->rtp, &rtp, sizeof(struct rtprio));
if (uap->pid == 0) {
p = curp;
PROC_LOCK(p);
} else {
p = pfind(uap->pid);
if (p == NULL)
return (ESRCH);
}
switch (uap->function) {
case RTP_LOOKUP:
if ((error = p_cansee(td, p)))
break;
mtx_lock_spin(&sched_lock);
pri_to_rtp(FIRST_KSEGRP_IN_PROC(p), &rtp);
mtx_unlock_spin(&sched_lock);
PROC_UNLOCK(p);
return (copyout(&rtp, uap->rtp, sizeof(struct rtprio)));
case RTP_SET:
if ((error = p_cansched(td, p)) || (error = cierror))
break;
/* disallow setting rtprio in most cases if not superuser */
if (suser(td) != 0) {
/* can't set someone else's */
if (uap->pid) {
error = EPERM;
break;
}
/* can't set realtime priority */
/*
* Realtime priority has to be restricted for reasons which should be
* obvious. However, for idle priority, there is a potential for
* system deadlock if an idleprio process gains a lock on a resource
* that other processes need (and the idleprio process can't run
* due to a CPU-bound normal process). Fix me! XXX
*/
#if 0
if (RTP_PRIO_IS_REALTIME(rtp.type))
#endif
if (rtp.type != RTP_PRIO_NORMAL) {
error = EPERM;
break;
}
}
mtx_lock_spin(&sched_lock);
error = rtp_to_pri(&rtp, FIRST_KSEGRP_IN_PROC(p));
mtx_unlock_spin(&sched_lock);
break;
default:
error = EINVAL;
break;
}
PROC_UNLOCK(p);
return (error);
}
int
rtp_to_pri(struct rtprio *rtp, struct ksegrp *kg)
{
if (rtp->prio > RTP_PRIO_MAX)
return (EINVAL);
switch (RTP_PRIO_BASE(rtp->type)) {
case RTP_PRIO_REALTIME:
kg->kg_user_pri = PRI_MIN_REALTIME + rtp->prio;
break;
case RTP_PRIO_NORMAL:
kg->kg_user_pri = PRI_MIN_TIMESHARE + rtp->prio;
break;
case RTP_PRIO_IDLE:
kg->kg_user_pri = PRI_MIN_IDLE + rtp->prio;
break;
default:
return (EINVAL);
}
kg->kg_pri_class = rtp->type;
if (curthread->td_ksegrp == kg) {
curthread->td_base_pri = kg->kg_user_pri;
curthread->td_priority = kg->kg_user_pri; /* XXX dubious */
}
return (0);
}
void
pri_to_rtp(struct ksegrp *kg, struct rtprio *rtp)
{
switch (PRI_BASE(kg->kg_pri_class)) {
case PRI_REALTIME:
rtp->prio = kg->kg_user_pri - PRI_MIN_REALTIME;
break;
case PRI_TIMESHARE:
rtp->prio = kg->kg_user_pri - PRI_MIN_TIMESHARE;
break;
case PRI_IDLE:
rtp->prio = kg->kg_user_pri - PRI_MIN_IDLE;
break;
default:
break;
}
rtp->type = kg->kg_pri_class;
}
#if defined(COMPAT_43) || defined(COMPAT_SUNOS)
#ifndef _SYS_SYSPROTO_H_
struct osetrlimit_args {
u_int which;
struct orlimit *rlp;
};
#endif
/*
* MPSAFE
*/
/* ARGSUSED */
int
osetrlimit(td, uap)
struct thread *td;
register struct osetrlimit_args *uap;
{
struct orlimit olim;
struct rlimit lim;
int error;
if ((error = copyin(uap->rlp, &olim, sizeof(struct orlimit))))
return (error);
lim.rlim_cur = olim.rlim_cur;
lim.rlim_max = olim.rlim_max;
mtx_lock(&Giant);
error = dosetrlimit(td, uap->which, &lim);
mtx_unlock(&Giant);
return (error);
}
#ifndef _SYS_SYSPROTO_H_
struct ogetrlimit_args {
u_int which;
struct orlimit *rlp;
};
#endif
/*
* MPSAFE
*/
/* ARGSUSED */
int
ogetrlimit(td, uap)
struct thread *td;
register struct ogetrlimit_args *uap;
{
struct proc *p = td->td_proc;
struct orlimit olim;
int error;
if (uap->which >= RLIM_NLIMITS)
return (EINVAL);
mtx_lock(&Giant);
olim.rlim_cur = p->p_rlimit[uap->which].rlim_cur;
if (olim.rlim_cur == -1)
olim.rlim_cur = 0x7fffffff;
olim.rlim_max = p->p_rlimit[uap->which].rlim_max;
if (olim.rlim_max == -1)
olim.rlim_max = 0x7fffffff;
error = copyout(&olim, uap->rlp, sizeof(olim));
mtx_unlock(&Giant);
return (error);
}
#endif /* COMPAT_43 || COMPAT_SUNOS */
#ifndef _SYS_SYSPROTO_H_
struct __setrlimit_args {
u_int which;
struct rlimit *rlp;
};
#endif
/*
* MPSAFE
*/
/* ARGSUSED */
int
setrlimit(td, uap)
struct thread *td;
register struct __setrlimit_args *uap;
{
struct rlimit alim;
int error;
if ((error = copyin(uap->rlp, &alim, sizeof (struct rlimit))))
return (error);
mtx_lock(&Giant);
error = dosetrlimit(td, uap->which, &alim);
mtx_unlock(&Giant);
return (error);
}
int
dosetrlimit(td, which, limp)
struct thread *td;
u_int which;
struct rlimit *limp;
{
struct proc *p = td->td_proc;
register struct rlimit *alimp;
int error;
GIANT_REQUIRED;
if (which >= RLIM_NLIMITS)
return (EINVAL);
alimp = &p->p_rlimit[which];
/*
* Preserve historical bugs by treating negative limits as unsigned.
*/
if (limp->rlim_cur < 0)
limp->rlim_cur = RLIM_INFINITY;
if (limp->rlim_max < 0)
limp->rlim_max = RLIM_INFINITY;
if (limp->rlim_cur > alimp->rlim_max ||
limp->rlim_max > alimp->rlim_max)
if ((error = suser_cred(td->td_ucred, PRISON_ROOT)))
return (error);
if (limp->rlim_cur > limp->rlim_max)
limp->rlim_cur = limp->rlim_max;
if (p->p_limit->p_refcnt > 1 &&
(p->p_limit->p_lflags & PL_SHAREMOD) == 0) {
p->p_limit->p_refcnt--;
p->p_limit = limcopy(p->p_limit);
alimp = &p->p_rlimit[which];
}
switch (which) {
case RLIMIT_CPU:
mtx_lock_spin(&sched_lock);
p->p_cpulimit = limp->rlim_cur;
mtx_unlock_spin(&sched_lock);
break;
case RLIMIT_DATA:
if (limp->rlim_cur > maxdsiz)
limp->rlim_cur = maxdsiz;
if (limp->rlim_max > maxdsiz)
limp->rlim_max = maxdsiz;
break;
case RLIMIT_STACK:
if (limp->rlim_cur > maxssiz)
limp->rlim_cur = maxssiz;
if (limp->rlim_max > maxssiz)
limp->rlim_max = maxssiz;
/*
* Stack is allocated to the max at exec time with only
* "rlim_cur" bytes accessible. If stack limit is going
* up make more accessible, if going down make inaccessible.
*/
if (limp->rlim_cur != alimp->rlim_cur) {
vm_offset_t addr;
vm_size_t size;
vm_prot_t prot;
if (limp->rlim_cur > alimp->rlim_cur) {
prot = p->p_sysent->sv_stackprot;
size = limp->rlim_cur - alimp->rlim_cur;
addr = p->p_sysent->sv_usrstack -
limp->rlim_cur;
} else {
prot = VM_PROT_NONE;
size = alimp->rlim_cur - limp->rlim_cur;
addr = p->p_sysent->sv_usrstack -
alimp->rlim_cur;
}
addr = trunc_page(addr);
size = round_page(size);
(void) vm_map_protect(&p->p_vmspace->vm_map,
addr, addr+size, prot, FALSE);
}
break;
case RLIMIT_NOFILE:
if (limp->rlim_cur > maxfilesperproc)
limp->rlim_cur = maxfilesperproc;
if (limp->rlim_max > maxfilesperproc)
limp->rlim_max = maxfilesperproc;
break;
case RLIMIT_NPROC:
if (limp->rlim_cur > maxprocperuid)
limp->rlim_cur = maxprocperuid;
if (limp->rlim_max > maxprocperuid)
limp->rlim_max = maxprocperuid;
if (limp->rlim_cur < 1)
limp->rlim_cur = 1;
if (limp->rlim_max < 1)
limp->rlim_max = 1;
break;
}
*alimp = *limp;
return (0);
}
#ifndef _SYS_SYSPROTO_H_
struct __getrlimit_args {
u_int which;
struct rlimit *rlp;
};
#endif
/*
* MPSAFE
*/
/* ARGSUSED */
int
getrlimit(td, uap)
struct thread *td;
register struct __getrlimit_args *uap;
{
int error;
struct proc *p = td->td_proc;
if (uap->which >= RLIM_NLIMITS)
return (EINVAL);
mtx_lock(&Giant);
error = copyout(&p->p_rlimit[uap->which], uap->rlp,
sizeof (struct rlimit));
mtx_unlock(&Giant);
return(error);
}
/*
* Transform the running time and tick information in proc p into user,
* system, and interrupt time usage.
*/
void
calcru(p, up, sp, ip)
struct proc *p;
struct timeval *up;
struct timeval *sp;
struct timeval *ip;
{
/* {user, system, interrupt, total} {ticks, usec}; previous tu: */
u_int64_t ut, uu, st, su, it, iu, tt, tu, ptu;
struct timeval tv;
struct bintime bt;
mtx_assert(&sched_lock, MA_OWNED);
/* XXX: why spl-protect ? worst case is an off-by-one report */
ut = p->p_uticks;
st = p->p_sticks;
it = p->p_iticks;
tt = ut + st + it;
if (tt == 0) {
st = 1;
tt = 1;
}
if (curthread->td_proc == p) {
/*
* Adjust for the current time slice. This is actually fairly
* important since the error here is on the order of a time
* quantum, which is much greater than the sampling error.
* XXXKSE use a different test due to threads on other
* processors also being 'current'.
*/
binuptime(&bt);
bintime_sub(&bt, PCPU_PTR(switchtime));
bintime_add(&bt, &p->p_runtime);
} else {
bt = p->p_runtime;
}
bintime2timeval(&bt, &tv);
tu = (u_int64_t)tv.tv_sec * 1000000 + tv.tv_usec;
ptu = p->p_uu + p->p_su + p->p_iu;
if (tu < ptu || (int64_t)tu < 0) {
/* XXX no %qd in kernel. Truncate. */
printf("calcru: negative time of %ld usec for pid %d (%s)\n",
(long)tu, p->p_pid, p->p_comm);
tu = ptu;
}
/* Subdivide tu. */
uu = (tu * ut) / tt;
su = (tu * st) / tt;
iu = tu - uu - su;
/* Enforce monotonicity. */
if (uu < p->p_uu || su < p->p_su || iu < p->p_iu) {
if (uu < p->p_uu)
uu = p->p_uu;
else if (uu + p->p_su + p->p_iu > tu)
uu = tu - p->p_su - p->p_iu;
if (st == 0)
su = p->p_su;
else {
su = ((tu - uu) * st) / (st + it);
if (su < p->p_su)
su = p->p_su;
else if (uu + su + p->p_iu > tu)
su = tu - uu - p->p_iu;
}
KASSERT(uu + su + p->p_iu <= tu,
("calcru: monotonisation botch 1"));
iu = tu - uu - su;
KASSERT(iu >= p->p_iu,
("calcru: monotonisation botch 2"));
}
p->p_uu = uu;
p->p_su = su;
p->p_iu = iu;
up->tv_sec = uu / 1000000;
up->tv_usec = uu % 1000000;
sp->tv_sec = su / 1000000;
sp->tv_usec = su % 1000000;
if (ip != NULL) {
ip->tv_sec = iu / 1000000;
ip->tv_usec = iu % 1000000;
}
}
#ifndef _SYS_SYSPROTO_H_
struct getrusage_args {
int who;
struct rusage *rusage;
};
#endif
/*
* MPSAFE
*/
/* ARGSUSED */
int
getrusage(td, uap)
register struct thread *td;
register struct getrusage_args *uap;
{
struct proc *p = td->td_proc;
register struct rusage *rup;
int error = 0;
mtx_lock(&Giant);
switch (uap->who) {
case RUSAGE_SELF:
rup = &p->p_stats->p_ru;
mtx_lock_spin(&sched_lock);
calcru(p, &rup->ru_utime, &rup->ru_stime, NULL);
mtx_unlock_spin(&sched_lock);
break;
case RUSAGE_CHILDREN:
rup = &p->p_stats->p_cru;
break;
default:
rup = NULL;
error = EINVAL;
break;
}
mtx_unlock(&Giant);
if (error == 0) {
error = copyout(rup, uap->rusage, sizeof (struct rusage));
}
return(error);
}
void
ruadd(ru, ru2)
register struct rusage *ru, *ru2;
{
register long *ip, *ip2;
register int i;
timevaladd(&ru->ru_utime, &ru2->ru_utime);
timevaladd(&ru->ru_stime, &ru2->ru_stime);
if (ru->ru_maxrss < ru2->ru_maxrss)
ru->ru_maxrss = ru2->ru_maxrss;
ip = &ru->ru_first; ip2 = &ru2->ru_first;
for (i = &ru->ru_last - &ru->ru_first; i >= 0; i--)
*ip++ += *ip2++;
}
/*
* Make a copy of the plimit structure.
* We share these structures copy-on-write after fork,
* and copy when a limit is changed.
*/
struct plimit *
limcopy(lim)
struct plimit *lim;
{
register struct plimit *copy;
MALLOC(copy, struct plimit *, sizeof(struct plimit),
M_SUBPROC, 0);
bcopy(lim->pl_rlimit, copy->pl_rlimit, sizeof(struct plimit));
copy->p_lflags = 0;
copy->p_refcnt = 1;
return (copy);
}
/*
* Find the uidinfo structure for a uid. This structure is used to
* track the total resource consumption (process count, socket buffer
* size, etc.) for the uid and impose limits.
*/
void
uihashinit()
{
uihashtbl = hashinit(maxproc / 16, M_UIDINFO, &uihash);
mtx_init(&uihashtbl_mtx, "uidinfo hash", NULL, MTX_DEF);
}
/*
* lookup a uidinfo struct for the parameter uid.
* uihashtbl_mtx must be locked.
*/
static struct uidinfo *
uilookup(uid)
uid_t uid;
{
struct uihashhead *uipp;
struct uidinfo *uip;
mtx_assert(&uihashtbl_mtx, MA_OWNED);
uipp = UIHASH(uid);
LIST_FOREACH(uip, uipp, ui_hash)
if (uip->ui_uid == uid)
break;
return (uip);
}
/*
* Find or allocate a struct uidinfo for a particular uid.
* Increase refcount on uidinfo struct returned.
* uifree() should be called on a struct uidinfo when released.
*/
struct uidinfo *
uifind(uid)
uid_t uid;
{
struct uidinfo *uip;
mtx_lock(&uihashtbl_mtx);
uip = uilookup(uid);
if (uip == NULL) {
struct uidinfo *old_uip;
mtx_unlock(&uihashtbl_mtx);
uip = malloc(sizeof(*uip), M_UIDINFO, M_ZERO);
mtx_lock(&uihashtbl_mtx);
/*
* There's a chance someone created our uidinfo while we
* were in malloc and not holding the lock, so we have to
* make sure we don't insert a duplicate uidinfo
*/
if ((old_uip = uilookup(uid)) != NULL) {
/* someone else beat us to it */
free(uip, M_UIDINFO);
uip = old_uip;
} else {
uip->ui_mtxp = mtx_pool_alloc();
uip->ui_uid = uid;
LIST_INSERT_HEAD(UIHASH(uid), uip, ui_hash);
}
}
uihold(uip);
mtx_unlock(&uihashtbl_mtx);
return (uip);
}
/*
* Place another refcount on a uidinfo struct.
*/
void
uihold(uip)
struct uidinfo *uip;
{
UIDINFO_LOCK(uip);
uip->ui_ref++;
UIDINFO_UNLOCK(uip);
}
/*-
* Since uidinfo structs have a long lifetime, we use an
* opportunistic refcounting scheme to avoid locking the lookup hash
* for each release.
*
* If the refcount hits 0, we need to free the structure,
* which means we need to lock the hash.
* Optimal case:
* After locking the struct and lowering the refcount, if we find
* that we don't need to free, simply unlock and return.
* Suboptimal case:
* If refcount lowering results in need to free, bump the count
* back up, loose the lock and aquire the locks in the proper
* order to try again.
*/
void
uifree(uip)
struct uidinfo *uip;
{
/* Prepare for optimal case. */
UIDINFO_LOCK(uip);
if (--uip->ui_ref != 0) {
UIDINFO_UNLOCK(uip);
return;
}
/* Prepare for suboptimal case. */
uip->ui_ref++;
UIDINFO_UNLOCK(uip);
mtx_lock(&uihashtbl_mtx);
UIDINFO_LOCK(uip);
/*
* We must subtract one from the count again because we backed out
* our initial subtraction before dropping the lock.
* Since another thread may have added a reference after we dropped the
* initial lock we have to test for zero again.
*/
if (--uip->ui_ref == 0) {
LIST_REMOVE(uip, ui_hash);
mtx_unlock(&uihashtbl_mtx);
if (uip->ui_sbsize != 0)
/* XXX no %qd in kernel. Truncate. */
printf("freeing uidinfo: uid = %d, sbsize = %ld\n",
uip->ui_uid, (long)uip->ui_sbsize);
if (uip->ui_proccnt != 0)
printf("freeing uidinfo: uid = %d, proccnt = %ld\n",
uip->ui_uid, uip->ui_proccnt);
UIDINFO_UNLOCK(uip);
FREE(uip, M_UIDINFO);
return;
}
mtx_unlock(&uihashtbl_mtx);
UIDINFO_UNLOCK(uip);
}
/*
* Change the count associated with number of processes
* a given user is using. When 'max' is 0, don't enforce a limit
*/
int
chgproccnt(uip, diff, max)
struct uidinfo *uip;
int diff;
int max;
{
UIDINFO_LOCK(uip);
/* don't allow them to exceed max, but allow subtraction */
if (diff > 0 && uip->ui_proccnt + diff > max && max != 0) {
UIDINFO_UNLOCK(uip);
return (0);
}
uip->ui_proccnt += diff;
if (uip->ui_proccnt < 0)
printf("negative proccnt for uid = %d\n", uip->ui_uid);
UIDINFO_UNLOCK(uip);
return (1);
}
/*
* Change the total socket buffer size a user has used.
*/
int
chgsbsize(uip, hiwat, to, max)
struct uidinfo *uip;
u_int *hiwat;
u_int to;
rlim_t max;
{
rlim_t new;
int s;
s = splnet();
UIDINFO_LOCK(uip);
new = uip->ui_sbsize + to - *hiwat;
/* don't allow them to exceed max, but allow subtraction */
if (to > *hiwat && new > max) {
splx(s);
UIDINFO_UNLOCK(uip);
return (0);
}
uip->ui_sbsize = new;
*hiwat = to;
if (uip->ui_sbsize < 0)
printf("negative sbsize for uid = %d\n", uip->ui_uid);
splx(s);
UIDINFO_UNLOCK(uip);
return (1);
}
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