Extend the support for exempting processes from being killed when swap is

exhausted.
- Add a new protect(1) command that can be used to set or revoke protection
  from arbitrary processes.  Similar to ktrace it can apply a change to all
  existing descendants of a process as well as future descendants.
- Add a new procctl(2) system call that provides a generic interface for
  control operations on processes (as opposed to the debugger-specific
  operations provided by ptrace(2)).  procctl(2) uses a combination of
  idtype_t and an id to identify the set of processes on which to operate
  similar to wait6().
- Add a PROC_SPROTECT control operation to manage the protection status
  of a set of processes.  MADV_PROTECT still works for backwards
  compatability.
- Add a p_flag2 to struct proc (and a corresponding ki_flag2 to kinfo_proc)
  the first bit of which is used to track if P_PROTECT should be inherited
  by new child processes.

Reviewed by:	kib, jilles (earlier version)
Approved by:	re (delphij)
MFC after:	1 month
This commit is contained in:
jhb 2013-09-19 18:53:42 +00:00
parent 8ecfe4666e
commit d3ef75b6c7
24 changed files with 696 additions and 16 deletions

View File

@ -197,6 +197,7 @@ MAN+= abort2.2 \
posix_fadvise.2 \
posix_fallocate.2 \
posix_openpt.2 \
procctl.2 \
profil.2 \
pselect.2 \
ptrace.2 \

View File

@ -395,6 +395,7 @@ FBSD_1.3 {
ffclock_setestimate;
pipe2;
posix_fadvise;
procctl;
wait6;
};
@ -822,6 +823,8 @@ FBSDprivate_1.0 {
__sys_poll;
_preadv;
__sys_preadv;
_procctl;
__sys_procctl;
_profil;
__sys_profil;
_pselect;

142
lib/libc/sys/procctl.2 Normal file
View File

@ -0,0 +1,142 @@
.\" Copyright (c) 2013 Advanced Computing Technologies LLC
.\" Written by: John H. Baldwin <jhb@FreeBSD.org>
.\" 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 AUTHOR 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 AUTHOR 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.
.\"
.\" $FreeBSD$
.\"
.Dd September 19, 2013
.Dt PROCCTL 2
.Os
.Sh NAME
.Nm procctl
.Nd control processes
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In sys/procctl.h
.Ft int
.Fn procctl "idtype_t idtype" "id_t id" "int cmd" "void *arg"
.Sh DESCRIPTION
The
.Fn procctl
system call provides for control over processes.
The
.Fa idtype
and
.Fa id
arguments specify the set of processes to control.
If multiple processes match the identifier,
.Nm
will make a
.Dq best effort
to control as many of the selected possibles as possible.
An error is only returned if no selected processes successfully complete
the request.
The following identifier types are supported:
.Bl -tag -width Dv P_PGID
.It Dv P_PID
Control the process with the process ID
.Fa id .
.It Dv P_PGID
Control processes belonging to the process group with the ID
.Fa id .
.El
.Pp
The control request to perform is specified by the
.Fa cmd
argument.
The following commands are supported:
.Bl -tag -width Dv PROC_SPROTECT
.It Dv PROC_SPROTECT
Set process protection state.
This is used to mark a process as protected from being killed if the system
exhausts available memory and swap.
The
.Fa arg
parameter must point to an integer containing an operation and zero or more
optional flags.
The following operations are supported:
.Bl -tag -width Dv PPROT_CLEAR
.It Dv PPROT_SET
Mark the selected processes as protected.
.It Dv PPROT_CLEAR
Clear the protected state of selected processes.
.El
.Pp
The following optional flags are supported:
.Bl -tag -width Dv PPROT_DESCEND
.It Dv PPROT_DESCEND
Apply the requested operation to all child processes of each selected process
in addition to each selected process.
.It Dv PPROT_INHERIT
When used with
.Dv PPROT_SET ,
mark all future child processes of each selected process as protected.
Future child processes will also mark all of their future child processes.
.El
.El
.Sh RETURN VALUES
If an error occurs, a value of -1 is returned and
.Va errno
is set to indicate the error.
.Sh ERRORS
The
.Fn procctl
system call
will fail if:
.Bl -tag -width Er
.It Bq Er EFAULT
The
.Fa arg
points outside the process's allocated address space.
.It Bq Er EINVAL
The
.Fa cmd
argument specifies an unsupported command.
.Pp
The
.Fa idtype
argument specifies an unsupported identifier type.
.It Bq Er EPERM
The calling process does not have permission to perform the requested
operation on any of the selected processes.
.It Bq Er ESRCH
No processes matched the requested
.Fa idtype
and
.Fa id .
.It Bq Er EINVAL
An invalid operation or flag was passed in
.Fa arg
for a
.Dv PROC_SPROTECT
command.
.El
.Sh SEE ALSO
.Xr ptrace 2
.Sh HISTORY
The
.Fn procctl
function appeared in
.Fx 10 .

View File

@ -342,6 +342,7 @@ struct kinfo_proc32 {
char ki_loginclass[LOGINCLASSLEN+1];
char ki_sparestrings[50];
int ki_spareints[KI_NSPARE_INT];
int ki_flag2;
int ki_fibnum;
u_int ki_cr_flags;
int ki_jid;

View File

@ -56,6 +56,7 @@ __FBSDID("$FreeBSD$");
#include <sys/mutex.h>
#include <sys/namei.h>
#include <sys/proc.h>
#include <sys/procctl.h>
#include <sys/reboot.h>
#include <sys/resource.h>
#include <sys/resourcevar.h>
@ -3000,3 +3001,23 @@ convert_sigevent32(struct sigevent32 *sig32, struct sigevent *sig)
}
return (0);
}
int
freebsd32_procctl(struct thread *td, struct freebsd32_procctl_args *uap)
{
void *data;
int error, flags;
switch (uap->com) {
case PROC_SPROTECT:
error = copyin(PTRIN(uap->data), &flags, sizeof(flags));
if (error)
return (error);
data = &flags;
break;
default:
return (EINVAL);
}
return (kern_procctl(td, uap->idtype, PAIR32TO64(id_t, uap->id),
uap->com, data));
}

View File

@ -1056,3 +1056,12 @@
542 AUE_PIPE NOPROTO { int pipe2(int *fildes, int flags); }
543 AUE_NULL NOSTD { int freebsd32_aio_mlock( \
struct aiocb32 *aiocbp); }
#ifdef PAD64_REQUIRED
544 AUE_NULL STD { int freebsd32_procctl(int idtype, int pad, \
uint32_t id1, uint32_t id2, int com, \
void *data); }
#else
544 AUE_NULL STD { int freebsd32_procctl(int idtype, \
uint32_t id1, uint32_t id2, int com, \
void *data); }
#endif

View File

@ -474,6 +474,7 @@ proc0_init(void *dummy __unused)
p->p_sysent = &null_sysvec;
p->p_flag = P_SYSTEM | P_INMEM;
p->p_flag2 = 0;
p->p_state = PRS_NORMAL;
knlist_init_mtx(&p->p_klist, &p->p_mtx);
STAILQ_INIT(&p->p_ktr);

View File

@ -489,6 +489,7 @@ do_fork(struct thread *td, int flags, struct proc *p2, struct thread *td2,
* Increase reference counts on shared objects.
*/
p2->p_flag = P_INMEM;
p2->p_flag2 = 0;
p2->p_swtick = ticks;
if (p1->p_flag & P_PROFIL)
startprofclock(p2);
@ -512,6 +513,11 @@ do_fork(struct thread *td, int flags, struct proc *p2, struct thread *td2,
p2->p_fd = fd;
p2->p_fdtol = fdtol;
if (p1->p_flag2 & P2_INHERIT_PROTECTED) {
p2->p_flag |= P_PROTECTED;
p2->p_flag2 |= P2_INHERIT_PROTECTED;
}
/*
* p_limit is copy-on-write. Bump its refcount.
*/

View File

@ -802,6 +802,7 @@ fill_kinfo_proc_only(struct proc *p, struct kinfo_proc *kp)
kp->ki_fd = p->p_fd;
kp->ki_vmspace = p->p_vmspace;
kp->ki_flag = p->p_flag;
kp->ki_flag2 = p->p_flag2;
cred = p->p_ucred;
if (cred) {
kp->ki_uid = cred->cr_uid;
@ -1161,6 +1162,7 @@ freebsd32_kinfo_proc_out(const struct kinfo_proc *ki, struct kinfo_proc32 *ki32)
bcopy(ki->ki_comm, ki32->ki_comm, COMMLEN + 1);
bcopy(ki->ki_emul, ki32->ki_emul, KI_EMULNAMELEN + 1);
bcopy(ki->ki_loginclass, ki32->ki_loginclass, LOGINCLASSLEN + 1);
CP(*ki, *ki32, ki_flag2);
CP(*ki, *ki32, ki_fibnum);
CP(*ki, *ki32, ki_cr_flags);
CP(*ki, *ki32, ki_jid);

View File

@ -41,7 +41,9 @@ __FBSDID("$FreeBSD$");
#include <sys/syscallsubr.h>
#include <sys/sysent.h>
#include <sys/sysproto.h>
#include <sys/priv.h>
#include <sys/proc.h>
#include <sys/procctl.h>
#include <sys/vnode.h>
#include <sys/ptrace.h>
#include <sys/rwlock.h>
@ -1240,3 +1242,196 @@ stopevent(struct proc *p, unsigned int event, unsigned int val)
msleep(&p->p_step, &p->p_mtx, PWAIT, "stopevent", 0);
} while (p->p_step);
}
static int
protect_setchild(struct thread *td, struct proc *p, int flags)
{
PROC_LOCK_ASSERT(p, MA_OWNED);
if (p->p_flag & P_SYSTEM || p_cansee(td, p) != 0)
return (0);
if (flags & PPROT_SET) {
p->p_flag |= P_PROTECTED;
if (flags & PPROT_INHERIT)
p->p_flag2 |= P2_INHERIT_PROTECTED;
} else {
p->p_flag &= ~P_PROTECTED;
p->p_flag2 &= ~P2_INHERIT_PROTECTED;
}
return (1);
}
static int
protect_setchildren(struct thread *td, struct proc *top, int flags)
{
struct proc *p;
int ret;
p = top;
ret = 0;
sx_assert(&proctree_lock, SX_LOCKED);
for (;;) {
ret |= protect_setchild(td, p, flags);
PROC_UNLOCK(p);
/*
* If this process has children, descend to them next,
* otherwise do any siblings, and if done with this level,
* follow back up the tree (but not past top).
*/
if (!LIST_EMPTY(&p->p_children))
p = LIST_FIRST(&p->p_children);
else for (;;) {
if (p == top) {
PROC_LOCK(p);
return (ret);
}
if (LIST_NEXT(p, p_sibling)) {
p = LIST_NEXT(p, p_sibling);
break;
}
p = p->p_pptr;
}
PROC_LOCK(p);
}
}
static int
protect_set(struct thread *td, struct proc *p, int flags)
{
int error, ret;
switch (PPROT_OP(flags)) {
case PPROT_SET:
case PPROT_CLEAR:
break;
default:
return (EINVAL);
}
if ((PPROT_FLAGS(flags) & ~(PPROT_DESCEND | PPROT_INHERIT)) != 0)
return (EINVAL);
error = priv_check(td, PRIV_VM_MADV_PROTECT);
if (error)
return (error);
if (flags & PPROT_DESCEND)
ret = protect_setchildren(td, p, flags);
else
ret = protect_setchild(td, p, flags);
if (ret == 0)
return (EPERM);
return (0);
}
#ifndef _SYS_SYSPROTO_H_
struct procctl_args {
idtype_t idtype;
id_t id;
int com;
void *data;
};
#endif
/* ARGSUSED */
int
sys_procctl(struct thread *td, struct procctl_args *uap)
{
int error, flags;
void *data;
switch (uap->com) {
case PROC_SPROTECT:
error = copyin(uap->data, &flags, sizeof(flags));
if (error)
return (error);
data = &flags;
break;
default:
return (EINVAL);
}
return (kern_procctl(td, uap->idtype, uap->id, uap->com, data));
}
static int
kern_procctl_single(struct thread *td, struct proc *p, int com, void *data)
{
PROC_LOCK_ASSERT(p, MA_OWNED);
switch (com) {
case PROC_SPROTECT:
return (protect_set(td, p, *(int *)data));
default:
return (EINVAL);
}
}
int
kern_procctl(struct thread *td, idtype_t idtype, id_t id, int com, void *data)
{
struct pgrp *pg;
struct proc *p;
int error, first_error, ok;
sx_slock(&proctree_lock);
switch (idtype) {
case P_PID:
p = pfind(id);
if (p == NULL) {
error = ESRCH;
break;
}
if (p->p_state == PRS_NEW)
error = ESRCH;
else
error = p_cansee(td, p);
if (error == 0)
error = kern_procctl_single(td, p, com, data);
PROC_UNLOCK(p);
break;
case P_PGID:
/*
* Attempt to apply the operation to all members of the
* group. Ignore processes in the group that can't be
* seen. Ignore errors so long as at least one process is
* able to complete the request successfully.
*/
pg = pgfind(id);
if (pg == NULL) {
error = ESRCH;
break;
}
PGRP_UNLOCK(pg);
ok = 0;
first_error = 0;
LIST_FOREACH(p, &pg->pg_members, p_pglist) {
PROC_LOCK(p);
if (p->p_state == PRS_NEW || p_cansee(td, p) != 0) {
PROC_UNLOCK(p);
continue;
}
error = kern_procctl_single(td, p, com, data);
PROC_UNLOCK(p);
if (error == 0)
ok = 1;
else if (first_error == 0)
first_error = error;
}
if (ok)
error = 0;
else if (first_error != 0)
error = first_error;
else
/*
* Was not able to see any processes in the
* process group.
*/
error = ESRCH;
break;
default:
error = EINVAL;
break;
}
sx_sunlock(&proctree_lock);
return (error);
}

View File

@ -978,5 +978,7 @@
int flags); }
542 AUE_PIPE STD { int pipe2(int *fildes, int flags); }
543 AUE_NULL NOSTD { int aio_mlock(struct aiocb *aiocbp); }
544 AUE_NULL STD { int procctl(idtype_t idtype, id_t id, \
int com, void *data); }
; Please copy any additions and changes to the following compatability tables:
; sys/compat/freebsd32/syscalls.master

View File

@ -492,11 +492,8 @@ struct proc {
struct callout p_limco; /* (c) Limit callout handle */
struct sigacts *p_sigacts; /* (x) Signal actions, state (CPU). */
/*
* The following don't make too much sense.
* See the td_ or ke_ versions of the same flags.
*/
int p_flag; /* (c) P_* flags. */
int p_flag2; /* (c) P2_* flags. */
enum {
PRS_NEW = 0, /* In creation */
PRS_NORMAL, /* threads can be run. */
@ -641,6 +638,9 @@ struct proc {
#define P_SHOULDSTOP(p) ((p)->p_flag & P_STOPPED)
#define P_KILLED(p) ((p)->p_flag & P_WKILLED)
/* These flags are kept in p_flag2. */
#define P2_INHERIT_PROTECTED 0x00000001 /* New children get P_PROTECTED. */
/*
* These were process status values (p_stat), now they are only used in
* legacy conversion code.

55
sys/sys/procctl.h Normal file
View File

@ -0,0 +1,55 @@
/*-
* Copyright (c) 2013 Advanced Computing Technologies LLC
* Written by: John H. Baldwin <jhb@FreeBSD.org>
* 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 AUTHOR 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 AUTHOR 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.
*
* $FreeBSD$
*/
#ifndef _SYS_PROCCTL_H_
#define _SYS_PROCCTL_H_
#define PROC_SPROTECT 1 /* set protected state */
/* Operations for PROC_SPROTECT (passed in integer arg). */
#define PPROT_OP(x) ((x) & 0xf)
#define PPROT_SET 1
#define PPROT_CLEAR 2
/* Flags for PROC_SPROTECT (ORed in with operation). */
#define PPROT_FLAGS(x) ((x) & ~0xf)
#define PPROT_DESCEND 0x10
#define PPROT_INHERIT 0x20
#ifndef _KERNEL
#include <sys/types.h>
#include <sys/wait.h>
__BEGIN_DECLS
int procctl(idtype_t, id_t, int, void *);
__END_DECLS
#endif
#endif /* !_SYS_PROCCTL_H_ */

View File

@ -167,6 +167,8 @@ int kern_posix_fadvise(struct thread *td, int fd, off_t offset, off_t len,
int advice);
int kern_posix_fallocate(struct thread *td, int fd, off_t offset,
off_t len);
int kern_procctl(struct thread *td, enum idtype idtype, id_t id, int com,
void *data);
int kern_preadv(struct thread *td, int fd, struct uio *auio, off_t offset);
int kern_pselect(struct thread *td, int nd, fd_set *in, fd_set *ou,
fd_set *ex, struct timeval *tvp, sigset_t *uset, int abi_nfdbits);

View File

@ -84,7 +84,7 @@
* it in two places: function fill_kinfo_proc in sys/kern/kern_proc.c and
* function kvm_proclist in lib/libkvm/kvm_proc.c .
*/
#define KI_NSPARE_INT 8
#define KI_NSPARE_INT 7
#define KI_NSPARE_LONG 12
#define KI_NSPARE_PTR 6
@ -187,6 +187,7 @@ struct kinfo_proc {
*/
char ki_sparestrings[50]; /* spare string space */
int ki_spareints[KI_NSPARE_INT]; /* spare room for growth */
int ki_flag2; /* P2_* flags */
int ki_fibnum; /* Default FIB number */
u_int ki_cr_flags; /* Credential flags */
int ki_jid; /* Process jail ID */

View File

@ -56,6 +56,7 @@ __FBSDID("$FreeBSD$");
#include <sys/filedesc.h>
#include <sys/priv.h>
#include <sys/proc.h>
#include <sys/procctl.h>
#include <sys/racct.h>
#include <sys/resource.h>
#include <sys/resourcevar.h>
@ -68,6 +69,7 @@ __FBSDID("$FreeBSD$");
#include <sys/mount.h>
#include <sys/conf.h>
#include <sys/stat.h>
#include <sys/syscallsubr.h>
#include <sys/sysent.h>
#include <sys/vmmeter.h>
@ -739,23 +741,18 @@ sys_madvise(td, uap)
{
vm_offset_t start, end;
vm_map_t map;
struct proc *p;
int error;
int flags;
/*
* Check for our special case, advising the swap pager we are
* "immortal."
*/
if (uap->behav == MADV_PROTECT) {
error = priv_check(td, PRIV_VM_MADV_PROTECT);
if (error == 0) {
p = td->td_proc;
PROC_LOCK(p);
p->p_flag |= P_PROTECTED;
PROC_UNLOCK(p);
}
return (error);
flags = PPROT_SET;
return (kern_procctl(td, P_PID, td->td_proc->p_pid,
PROC_SPROTECT, &flags));
}
/*
* Check for illegal behavior
*/

View File

@ -132,6 +132,7 @@ SUBDIR= alias \
printenv \
printf \
procstat \
protect \
rctl \
renice \
rev \

View File

@ -1161,6 +1161,18 @@ ktrsyscall(struct ktr_syscall *ktr, u_int flags)
ip++;
narg--;
break;
case SYS_procctl:
putchar('(');
idtypename(*ip, decimal);
c = ',';
ip++;
narg--;
print_number(ip, narg, c);
putchar(',');
procctlcmdname(*ip);
ip++;
narg--;
break;
}
}
while (narg > 0) {

View File

@ -169,6 +169,7 @@ cat <<_EOF_
#include <netinet/in.h>
#include <sys/param.h>
#include <sys/mount.h>
#include <sys/procctl.h>
#include <sys/ptrace.h>
#include <sys/resource.h>
#include <sys/reboot.h>
@ -465,6 +466,7 @@ auto_or_type "mountflagsname" "MNT_[A-Z]+[[:space:]]+0x[0-9]+"
auto_switch_type "msyncflagsname" "MS_[A-Z]+[[:space:]]+0x[0-9]+" "sys/mman.h"
auto_or_type "nfssvcname" "NFSSVC_[A-Z0-9]+[[:space:]]+0x[0-9]+" "nfs/nfssvc.h"
auto_switch_type "prioname" "PRIO_[A-Z]+[[:space:]]+[0-9]" "sys/resource.h"
auto_switch_type "procctlcmdname" "PROC_[A-Z]+[[:space:]]+[0-9]" "sys/procctl.h"
auto_switch_type "ptraceopname" "PT_[[:alnum:]_]+[[:space:]]+[0-9]+" "sys/ptrace.h"
auto_switch_type "quotactlname" "Q_[A-Z]+[[:space:]]+0x[0-9]+" "ufs/ufs/quota.h"
auto_or_type "rebootoptname" "RB_[A-Z]+[[:space:]]+0x[0-9]+" "sys/reboot.h"

6
usr.bin/protect/Makefile Normal file
View File

@ -0,0 +1,6 @@
# $FreeBSD$
PROG= protect
WARNS?= 6
.include <bsd.prog.mk>

89
usr.bin/protect/protect.1 Normal file
View File

@ -0,0 +1,89 @@
.\" Copyright (c) 2013 Advanced Computing Technologies LLC
.\" Written by: John H. Baldwin <jhb@FreeBSD.org>
.\" 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 AUTHOR 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 AUTHOR 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.
.\"
.\" $FreeBSD$
.\"
.Dd September 19, 2013
.Dt PROTECT 1
.Os
.Sh NAME
.Nm protect
.Nd "protect processes from being killed when swap space is exhausted"
.Sh SYNOPSIS
.Nm
.Op Fl i
.Ar command
.Nm
.Op Fl cdi
.Fl g Ar pgrp | Fl p Ar pid
.Sh DESCRIPTION
The
.Nm
command is used to mark processes as protected.
The kernel does not kill protected processes when swap space is exhausted.
Note that this protected state is not inherited by child processes by default.
.Pp
The options are:
.Bl -tag -width indent
.It Fl c
Remove protection from the specified processes.
.It Fl d
Apply the operation to all current children of the specified processes.
.It Fl i
Apply the operation to all future children of the specified processes.
.It Fl g Ar pgrp
Apply the operation to all processes in the specified process group.
.It Fl p Ar pid
Apply the operation to the specified process.
.It Ar command
Execute
.Ar command
as a protected process.
.El
.Pp
Note that only one of the
.Fl p
or
.Fl g
flags may be specified when adjusting the state of existing processes.
.Sh EXIT STATUS
.Ex -std
.Sh EXAMPLES
Mark the Xorg server as protected:
.Pp
.Dl "pgrep Xorg | xargs protect -p"
Protect all ssh sessions and their child processes:
.Pp
.Dl "pgrep sshd | xargs protect -dip"
Remove protection from all current and future processes:
.Pp
.Dl "protect -cdi -p 1"
.Sh SEE ALSO
.Xr pprotect 2
.Sh BUGS
If you protect a runaway process that allocates all memory the system will
deadlock.
.Pp
Inheritance of the protected state is not yet implemented.

122
usr.bin/protect/protect.c Normal file
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@ -0,0 +1,122 @@
/*-
* Copyright (c) 2013 Advanced Computing Technologies LLC
* Written by: John H. Baldwin <jhb@FreeBSD.org>
* 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 AUTHOR 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 AUTHOR 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/procctl.h>
#include <sys/types.h>
#include <sys/mman.h>
#include <err.h>
#include <errno.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
static void
usage(void)
{
fprintf(stderr, "usage: protect [-i] command\n");
fprintf(stderr, " protect [-cdi] -g pgrp | -p pid\n");
exit(1);
}
static id_t
parse_id(char *id)
{
static bool first = true;
long value;
char *ch;
if (!first) {
warnx("only one -g or -p flag is permitted");
usage();
}
value = strtol(id, &ch, 0);
if (*ch != '\0') {
warnx("invalid process id");
usage();
}
return (value);
}
int
main(int argc, char *argv[])
{
idtype_t idtype;
id_t id;
int ch, flags;
bool descend, inherit, idset;
idtype = P_PID;
id = getpid();
flags = PPROT_SET;
descend = inherit = idset = false;
while ((ch = getopt(argc, argv, "cdig:p:")) != -1)
switch (ch) {
case 'c':
flags = PPROT_CLEAR;
break;
case 'd':
descend = true;
break;
case 'i':
inherit = true;
break;
case 'g':
idtype = P_PGID;
id = parse_id(optarg);
idset = true;
break;
case 'p':
idtype = P_PID;
id = parse_id(optarg);
idset = true;
break;
}
argc -= optind;
argv += optind;
if ((idset && argc != 0) || (!idset && (argc == 0 || descend)))
usage();
if (descend)
flags |= PPROT_DESCEND;
if (inherit)
flags |= PPROT_INHERIT;
if (procctl(idtype, id, PROC_SPROTECT, &flags) == -1)
err(1, "procctl");
if (argc != 0) {
errno = 0;
execvp(*argv, argv);
err(errno == ENOENT ? 127 : 126, "%s", *argv);
}
return (0);
}

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@ -40,7 +40,7 @@ enum Argtype { None = 1, Hex, Octal, Int, Name, Ptr, Stat, Ioctl, Quad,
Fd_set, Sigaction, Fcntl, Mprot, Mmapflags, Whence, Readlinkres,
Umtx, Sigset, Sigprocmask, Kevent, Sockdomain, Socktype, Open,
Fcntlflag, Rusage, BinString, Shutdown, Resource, Rlimit, Timeval2,
Pathconf, Rforkflags, ExitStatus, Waitoptions, Idtype };
Pathconf, Rforkflags, ExitStatus, Waitoptions, Idtype, Procctl };
#define ARG_MASK 0xff
#define OUT 0x100

View File

@ -41,6 +41,7 @@ static const char rcsid[] =
#include <sys/types.h>
#include <sys/mman.h>
#include <sys/procctl.h>
#include <sys/ptrace.h>
#include <sys/socket.h>
#include <sys/time.h>
@ -270,6 +271,8 @@ static struct syscall syscalls[] = {
{ .name = "wait6", .ret_type = 1, .nargs = 6,
.args = { { Idtype, 0 }, { Int, 1 }, { ExitStatus | OUT, 2 },
{ Waitoptions, 3 }, { Rusage | OUT, 4 }, { Ptr, 5 } } },
{ .name = "procctl", .ret_type = 1, .nargs = 4,
.args = { { Idtype, 0 }, { Int, 1 }, { Procctl, 2 }, { Ptr, 3 } } },
{ .name = 0 },
};
@ -399,6 +402,10 @@ static struct xlat idtype_arg[] = {
X(P_CTID) X(P_CPUID) X(P_PSETID) XEND
};
static struct xlat procctl_arg[] = {
X(PROC_SPROTECT) XEND
};
#undef X
#undef XEND
@ -1198,6 +1205,9 @@ print_arg(struct syscall_args *sc, unsigned long *args, long retval,
case Idtype:
tmp = strdup(xlookup(idtype_arg, args[sc->offset]));
break;
case Procctl:
tmp = strdup(xlookup(procctl_arg, args[sc->offset]));
break;
default:
errx(1, "Invalid argument type %d\n", sc->type & ARG_MASK);
}