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/* $OpenBSD: kern_resource.c,v 1.81 2024/04/17 09:41:44 claudio Exp $ */
/* $NetBSD: kern_resource.c,v 1.38 1996/10/23 07:19:38 matthias Exp $ */
/*-
* 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. 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
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/file.h>
#include <sys/resourcevar.h>
#include <sys/pool.h>
#include <sys/proc.h>
#include <sys/ktrace.h>
#include <sys/sched.h>
#include <sys/signalvar.h>
#include <sys/mount.h>
#include <sys/syscallargs.h>
#include <uvm/uvm_extern.h>
#include <uvm/uvm.h>
/* Resource usage check interval in msec */
#define RUCHECK_INTERVAL 1000
/* SIGXCPU interval in seconds of process runtime */
#define SIGXCPU_INTERVAL 5
struct plimit *lim_copy(struct plimit *);
struct plimit *lim_write_begin(void);
void lim_write_commit(struct plimit *);
void tuagg_sub(struct tusage *, struct proc *, const struct timespec *);
/*
* Patchable maximum data and stack limits.
*/
rlim_t maxdmap = MAXDSIZ;
rlim_t maxsmap = MAXSSIZ;
/*
* Serializes resource limit updates.
* This lock has to be held together with ps_mtx when updating
* the process' ps_limit.
*/
struct rwlock rlimit_lock = RWLOCK_INITIALIZER("rlimitlk");
/*
* Resource controls and accounting.
*/
int
sys_getpriority(struct proc *curp, void *v, register_t *retval)
{
struct sys_getpriority_args /* {
syscallarg(int) which;
syscallarg(id_t) who;
} */ *uap = v;
struct process *pr;
int low = NZERO + PRIO_MAX + 1;
switch (SCARG(uap, which)) {
case PRIO_PROCESS:
if (SCARG(uap, who) == 0)
pr = curp->p_p;
else
pr = prfind(SCARG(uap, who));
if (pr == NULL)
break;
if (pr->ps_nice < low)
low = pr->ps_nice;
break;
case PRIO_PGRP: {
struct pgrp *pg;
if (SCARG(uap, who) == 0)
pg = curp->p_p->ps_pgrp;
else if ((pg = pgfind(SCARG(uap, who))) == NULL)
break;
LIST_FOREACH(pr, &pg->pg_members, ps_pglist)
if (pr->ps_nice < low)
low = pr->ps_nice;
break;
}
case PRIO_USER:
if (SCARG(uap, who) == 0)
SCARG(uap, who) = curp->p_ucred->cr_uid;
LIST_FOREACH(pr, &allprocess, ps_list)
if (pr->ps_ucred->cr_uid == SCARG(uap, who) &&
pr->ps_nice < low)
low = pr->ps_nice;
break;
default:
return (EINVAL);
}
if (low == NZERO + PRIO_MAX + 1)
return (ESRCH);
*retval = low - NZERO;
return (0);
}
int
sys_setpriority(struct proc *curp, void *v, register_t *retval)
{
struct sys_setpriority_args /* {
syscallarg(int) which;
syscallarg(id_t) who;
syscallarg(int) prio;
} */ *uap = v;
struct process *pr;
int found = 0, error = 0;
switch (SCARG(uap, which)) {
case PRIO_PROCESS:
if (SCARG(uap, who) == 0)
pr = curp->p_p;
else
pr = prfind(SCARG(uap, who));
if (pr == NULL)
break;
error = donice(curp, pr, SCARG(uap, prio));
found = 1;
break;
case PRIO_PGRP: {
struct pgrp *pg;
if (SCARG(uap, who) == 0)
pg = curp->p_p->ps_pgrp;
else if ((pg = pgfind(SCARG(uap, who))) == NULL)
break;
LIST_FOREACH(pr, &pg->pg_members, ps_pglist) {
error = donice(curp, pr, SCARG(uap, prio));
found = 1;
}
break;
}
case PRIO_USER:
if (SCARG(uap, who) == 0)
SCARG(uap, who) = curp->p_ucred->cr_uid;
LIST_FOREACH(pr, &allprocess, ps_list)
if (pr->ps_ucred->cr_uid == SCARG(uap, who)) {
error = donice(curp, pr, SCARG(uap, prio));
found = 1;
}
break;
default:
return (EINVAL);
}
if (!found)
return (ESRCH);
return (error);
}
int
donice(struct proc *curp, struct process *chgpr, int n)
{
struct ucred *ucred = curp->p_ucred;
struct proc *p;
int s;
if (ucred->cr_uid != 0 && ucred->cr_ruid != 0 &&
ucred->cr_uid != chgpr->ps_ucred->cr_uid &&
ucred->cr_ruid != chgpr->ps_ucred->cr_uid)
return (EPERM);
if (n > PRIO_MAX)
n = PRIO_MAX;
if (n < PRIO_MIN)
n = PRIO_MIN;
n += NZERO;
if (n < chgpr->ps_nice && suser(curp))
return (EACCES);
chgpr->ps_nice = n;
SCHED_LOCK(s);
TAILQ_FOREACH(p, &chgpr->ps_threads, p_thr_link) {
setpriority(p, p->p_estcpu, n);
}
SCHED_UNLOCK(s);
return (0);
}
int
sys_setrlimit(struct proc *p, void *v, register_t *retval)
{
struct sys_setrlimit_args /* {
syscallarg(int) which;
syscallarg(const struct rlimit *) rlp;
} */ *uap = v;
struct rlimit alim;
int error;
error = copyin((caddr_t)SCARG(uap, rlp), (caddr_t)&alim,
sizeof (struct rlimit));
if (error)
return (error);
#ifdef KTRACE
if (KTRPOINT(p, KTR_STRUCT))
ktrrlimit(p, &alim);
#endif
return (dosetrlimit(p, SCARG(uap, which), &alim));
}
int
dosetrlimit(struct proc *p, u_int which, struct rlimit *limp)
{
struct rlimit *alimp;
struct plimit *limit;
rlim_t maxlim;
int error;
if (which >= RLIM_NLIMITS || limp->rlim_cur > limp->rlim_max)
return (EINVAL);
rw_enter_write(&rlimit_lock);
alimp = &p->p_p->ps_limit->pl_rlimit[which];
if (limp->rlim_max > alimp->rlim_max) {
if ((error = suser(p)) != 0) {
rw_exit_write(&rlimit_lock);
return (error);
}
}
/* Get exclusive write access to the limit structure. */
limit = lim_write_begin();
alimp = &limit->pl_rlimit[which];
switch (which) {
case RLIMIT_DATA:
maxlim = maxdmap;
break;
case RLIMIT_STACK:
maxlim = maxsmap;
break;
case RLIMIT_NOFILE:
maxlim = maxfiles;
break;
case RLIMIT_NPROC:
maxlim = maxprocess;
break;
default:
maxlim = RLIM_INFINITY;
break;
}
if (limp->rlim_max > maxlim)
limp->rlim_max = maxlim;
if (limp->rlim_cur > limp->rlim_max)
limp->rlim_cur = limp->rlim_max;
if (which == RLIMIT_CPU && limp->rlim_cur != RLIM_INFINITY &&
alimp->rlim_cur == RLIM_INFINITY)
timeout_add_msec(&p->p_p->ps_rucheck_to, RUCHECK_INTERVAL);
if (which == RLIMIT_STACK) {
/*
* 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) {
vaddr_t addr;
vsize_t size;
vm_prot_t prot;
struct vmspace *vm = p->p_vmspace;
if (limp->rlim_cur > alimp->rlim_cur) {
prot = PROT_READ | PROT_WRITE;
size = limp->rlim_cur - alimp->rlim_cur;
#ifdef MACHINE_STACK_GROWS_UP
addr = (vaddr_t)vm->vm_maxsaddr +
alimp->rlim_cur;
#else
addr = (vaddr_t)vm->vm_minsaddr -
limp->rlim_cur;
#endif
} else {
prot = PROT_NONE;
size = alimp->rlim_cur - limp->rlim_cur;
#ifdef MACHINE_STACK_GROWS_UP
addr = (vaddr_t)vm->vm_maxsaddr +
limp->rlim_cur;
#else
addr = (vaddr_t)vm->vm_minsaddr -
alimp->rlim_cur;
#endif
}
addr = trunc_page(addr);
size = round_page(size);
KERNEL_LOCK();
(void) uvm_map_protect(&vm->vm_map, addr,
addr+size, prot, UVM_ET_STACK, FALSE, FALSE);
KERNEL_UNLOCK();
}
}
*alimp = *limp;
lim_write_commit(limit);
rw_exit_write(&rlimit_lock);
return (0);
}
int
sys_getrlimit(struct proc *p, void *v, register_t *retval)
{
struct sys_getrlimit_args /* {
syscallarg(int) which;
syscallarg(struct rlimit *) rlp;
} */ *uap = v;
struct plimit *limit;
struct rlimit alimp;
int error;
if (SCARG(uap, which) < 0 || SCARG(uap, which) >= RLIM_NLIMITS)
return (EINVAL);
limit = lim_read_enter();
alimp = limit->pl_rlimit[SCARG(uap, which)];
lim_read_leave(limit);
error = copyout(&alimp, SCARG(uap, rlp), sizeof(struct rlimit));
#ifdef KTRACE
if (error == 0 && KTRPOINT(p, KTR_STRUCT))
ktrrlimit(p, &alimp);
#endif
return (error);
}
void
tuagg_sub(struct tusage *tup, struct proc *p, const struct timespec *ts)
{
if (ts != NULL)
timespecadd(&tup->tu_runtime, ts, &tup->tu_runtime);
tup->tu_uticks += p->p_uticks;
tup->tu_sticks += p->p_sticks;
tup->tu_iticks += p->p_iticks;
}
/*
* Aggregate a single thread's immediate time counts into the running
* totals for the thread and process
*/
void
tuagg_locked(struct process *pr, struct proc *p, const struct timespec *ts)
{
tuagg_sub(&pr->ps_tu, p, ts);
tuagg_sub(&p->p_tu, p, ts);
p->p_uticks = 0;
p->p_sticks = 0;
p->p_iticks = 0;
}
void
tuagg(struct process *pr, struct proc *p)
{
int s;
SCHED_LOCK(s);
tuagg_locked(pr, p, NULL);
SCHED_UNLOCK(s);
}
/*
* Transform the running time and tick information in a struct tusage
* into user, system, and interrupt time usage.
*/
void
calctsru(struct tusage *tup, struct timespec *up, struct timespec *sp,
struct timespec *ip)
{
u_quad_t st, ut, it;
st = tup->tu_sticks;
ut = tup->tu_uticks;
it = tup->tu_iticks;
if (st + ut + it == 0) {
timespecclear(up);
timespecclear(sp);
if (ip != NULL)
timespecclear(ip);
return;
}
st = st * 1000000000 / stathz;
sp->tv_sec = st / 1000000000;
sp->tv_nsec = st % 1000000000;
ut = ut * 1000000000 / stathz;
up->tv_sec = ut / 1000000000;
up->tv_nsec = ut % 1000000000;
if (ip != NULL) {
it = it * 1000000000 / stathz;
ip->tv_sec = it / 1000000000;
ip->tv_nsec = it % 1000000000;
}
}
void
calcru(struct tusage *tup, struct timeval *up, struct timeval *sp,
struct timeval *ip)
{
struct timespec u, s, i;
calctsru(tup, &u, &s, ip != NULL ? &i : NULL);
TIMESPEC_TO_TIMEVAL(up, &u);
TIMESPEC_TO_TIMEVAL(sp, &s);
if (ip != NULL)
TIMESPEC_TO_TIMEVAL(ip, &i);
}
int
sys_getrusage(struct proc *p, void *v, register_t *retval)
{
struct sys_getrusage_args /* {
syscallarg(int) who;
syscallarg(struct rusage *) rusage;
} */ *uap = v;
struct rusage ru;
int error;
error = dogetrusage(p, SCARG(uap, who), &ru);
if (error == 0) {
error = copyout(&ru, SCARG(uap, rusage), sizeof(ru));
#ifdef KTRACE
if (error == 0 && KTRPOINT(p, KTR_STRUCT))
ktrrusage(p, &ru);
#endif
}
return (error);
}
int
dogetrusage(struct proc *p, int who, struct rusage *rup)
{
struct process *pr = p->p_p;
struct proc *q;
KERNEL_ASSERT_LOCKED();
switch (who) {
case RUSAGE_SELF:
/* start with the sum of dead threads, if any */
if (pr->ps_ru != NULL)
*rup = *pr->ps_ru;
else
memset(rup, 0, sizeof(*rup));
/* add on all living threads */
TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) {
ruadd(rup, &q->p_ru);
tuagg(pr, q);
}
calcru(&pr->ps_tu, &rup->ru_utime, &rup->ru_stime, NULL);
break;
case RUSAGE_THREAD:
*rup = p->p_ru;
calcru(&p->p_tu, &rup->ru_utime, &rup->ru_stime, NULL);
break;
case RUSAGE_CHILDREN:
*rup = pr->ps_cru;
break;
default:
return (EINVAL);
}
return (0);
}
void
ruadd(struct rusage *ru, struct rusage *ru2)
{
long *ip, *ip2;
int i;
timeradd(&ru->ru_utime, &ru2->ru_utime, &ru->ru_utime);
timeradd(&ru->ru_stime, &ru2->ru_stime, &ru->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++;
}
/*
* Check if the process exceeds its cpu resource allocation.
* If over max, kill it.
*/
void
rucheck(void *arg)
{
struct rlimit rlim;
struct process *pr = arg;
time_t runtime;
int s;
KERNEL_ASSERT_LOCKED();
SCHED_LOCK(s);
runtime = pr->ps_tu.tu_runtime.tv_sec;
SCHED_UNLOCK(s);
mtx_enter(&pr->ps_mtx);
rlim = pr->ps_limit->pl_rlimit[RLIMIT_CPU];
mtx_leave(&pr->ps_mtx);
if ((rlim_t)runtime >= rlim.rlim_cur) {
if ((rlim_t)runtime >= rlim.rlim_max) {
prsignal(pr, SIGKILL);
} else if (runtime >= pr->ps_nextxcpu) {
prsignal(pr, SIGXCPU);
pr->ps_nextxcpu = runtime + SIGXCPU_INTERVAL;
}
}
timeout_add_msec(&pr->ps_rucheck_to, RUCHECK_INTERVAL);
}
struct pool plimit_pool;
void
lim_startup(struct plimit *limit0)
{
rlim_t lim;
int i;
pool_init(&plimit_pool, sizeof(struct plimit), 0, IPL_MPFLOOR,
PR_WAITOK, "plimitpl", NULL);
for (i = 0; i < nitems(limit0->pl_rlimit); i++)
limit0->pl_rlimit[i].rlim_cur =
limit0->pl_rlimit[i].rlim_max = RLIM_INFINITY;
limit0->pl_rlimit[RLIMIT_NOFILE].rlim_cur = NOFILE;
limit0->pl_rlimit[RLIMIT_NOFILE].rlim_max = MIN(NOFILE_MAX,
(maxfiles - NOFILE > NOFILE) ? maxfiles - NOFILE : NOFILE);
limit0->pl_rlimit[RLIMIT_NPROC].rlim_cur = MAXUPRC;
lim = ptoa(uvmexp.free);
limit0->pl_rlimit[RLIMIT_RSS].rlim_max = lim;
lim = ptoa(64*1024); /* Default to very low */
limit0->pl_rlimit[RLIMIT_MEMLOCK].rlim_max = lim;
limit0->pl_rlimit[RLIMIT_MEMLOCK].rlim_cur = lim / 3;
refcnt_init(&limit0->pl_refcnt);
}
/*
* 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 *
lim_copy(struct plimit *lim)
{
struct plimit *newlim;
newlim = pool_get(&plimit_pool, PR_WAITOK);
memcpy(newlim->pl_rlimit, lim->pl_rlimit,
sizeof(struct rlimit) * RLIM_NLIMITS);
refcnt_init(&newlim->pl_refcnt);
return (newlim);
}
void
lim_free(struct plimit *lim)
{
if (refcnt_rele(&lim->pl_refcnt) == 0)
return;
pool_put(&plimit_pool, lim);
}
void
lim_fork(struct process *parent, struct process *child)
{
struct plimit *limit;
mtx_enter(&parent->ps_mtx);
limit = parent->ps_limit;
refcnt_take(&limit->pl_refcnt);
mtx_leave(&parent->ps_mtx);
child->ps_limit = limit;
if (limit->pl_rlimit[RLIMIT_CPU].rlim_cur != RLIM_INFINITY)
timeout_add_msec(&child->ps_rucheck_to, RUCHECK_INTERVAL);
}
/*
* Return an exclusive write reference to the process' resource limit structure.
* The caller has to release the structure by calling lim_write_commit().
*
* This invalidates any plimit read reference held by the calling thread.
*/
struct plimit *
lim_write_begin(void)
{
struct plimit *limit;
struct proc *p = curproc;
rw_assert_wrlock(&rlimit_lock);
if (p->p_limit != NULL)
lim_free(p->p_limit);
p->p_limit = NULL;
/*
* It is safe to access ps_limit here without holding ps_mtx
* because rlimit_lock excludes other writers.
*/
limit = p->p_p->ps_limit;
if (P_HASSIBLING(p) || refcnt_shared(&limit->pl_refcnt))
limit = lim_copy(limit);
return (limit);
}
/*
* Finish exclusive write access to the plimit structure.
* This makes the structure visible to other threads in the process.
*/
void
lim_write_commit(struct plimit *limit)
{
struct plimit *olimit;
struct proc *p = curproc;
rw_assert_wrlock(&rlimit_lock);
if (limit != p->p_p->ps_limit) {
mtx_enter(&p->p_p->ps_mtx);
olimit = p->p_p->ps_limit;
p->p_p->ps_limit = limit;
mtx_leave(&p->p_p->ps_mtx);
lim_free(olimit);
}
}
/*
* Begin read access to the process' resource limit structure.
* The access has to be finished by calling lim_read_leave().
*
* Sections denoted by lim_read_enter() and lim_read_leave() cannot nest.
*/
struct plimit *
lim_read_enter(void)
{
struct plimit *limit;
struct proc *p = curproc;
struct process *pr = p->p_p;
/*
* This thread might not observe the latest value of ps_limit
* if another thread updated the limits very recently on another CPU.
* However, the anomaly should disappear quickly, especially if
* there is any synchronization activity between the threads (or
* the CPUs).
*/
limit = p->p_limit;
if (limit != pr->ps_limit) {
mtx_enter(&pr->ps_mtx);
limit = pr->ps_limit;
refcnt_take(&limit->pl_refcnt);
mtx_leave(&pr->ps_mtx);
if (p->p_limit != NULL)
lim_free(p->p_limit);
p->p_limit = limit;
}
KASSERT(limit != NULL);
return (limit);
}
/*
* Get the value of the resource limit in given process.
*/
rlim_t
lim_cur_proc(struct proc *p, int which)
{
struct process *pr = p->p_p;
rlim_t val;
KASSERT(which >= 0 && which < RLIM_NLIMITS);
mtx_enter(&pr->ps_mtx);
val = pr->ps_limit->pl_rlimit[which].rlim_cur;
mtx_leave(&pr->ps_mtx);
return (val);
}
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