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Add a facility for non-init process to declare itself the reaper of

Browse Source 
the orphaned descendants.  Base of the API is modelled after the same
feature from the DragonFlyBSD.

Requested by:	bapt
Reviewed by:	jilles (previous version)
Tested by:	pho
Sponsored by:	The FreeBSD Foundation
MFC after:	3 weeks
This commit is contained in:
Konstantin Belousov 2014-12-15 12:01:42 +00:00
parent 1f7f3314d1
commit 237623b028
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=275800
11 changed files with 850 additions and 211 deletions
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215
lib/libc/sys/procctl.2
View File

@ -2,6 +2,10 @@
.\" Written by: John H. Baldwin <jhb@FreeBSD.org>
.\" All rights reserved.
.\"
.\" Copyright (c) 2014 The FreeBSD Foundation
.\" Portions of this documentation were written by Konstantin Belousov
.\" under sponsorship from the FreeBSD Foundation.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
@ -25,7 +29,7 @@
.\"
.\" $FreeBSD$
.\"
.Dd September 19, 2013
.Dd December 15, 2014
.Dt PROCCTL 2
.Os
.Sh NAME
@ -67,7 +71,7 @@ The control request to perform is specified by the
.Fa cmd
argument.
The following commands are supported:
.Bl -tag -width "Dv PROC_SPROTECT"
.Bl -tag -width "Dv PROC_REAP_GETPIDS"
.It Dv PROC_SPROTECT
Set process protection state.
This is used to mark a process as protected from being killed if the system
@ -95,6 +99,174 @@ When used with
mark all future child processes of each selected process as protected.
Future child processes will also mark all of their future child processes.
.El
.It Dv PROC_REAP_ACQUIRE
Acquires the reaper status for the current process.
The status means that orphaned children by the reaper descendants,
forked after the acquisition of the status, are reparented to the
reaper.
After the system initialization,
.Xr init 8
is the default reaper.
.Pp
.It Dv PROC_REAP_RELEASE
Releases the reaper state fpr the current process.
The reaper of the current process becomes the new reaper of the
current process descendants.
.It Dv PROC_REAP_STATUS
Provides the information about the reaper of the specified process,
or the process itself, in case it is a reaper.
The
.Fa data
argument must point to the
.Vt "struct procctl_reaper_status" ,
which if filled by the syscall on successfull return.
.Bd -literal
struct procctl_reaper_status {
u_int rs_flags;
u_int rs_children;
u_int rs_descendants;
pid_t rs_reaper;
pid_t rs_pid;
};
.Ed
The
.Fa rs_flags
may have the following flags returned:
.Bl -tag -width "Dv REAPER_STATUS_REALINIT"
.It Dv REAPER_STATUS_OWNED
The specified process has acquired the reaper status and did not
released it.
When the flag is returned, the
.Fa id
pid identifies reaper, otherwise the
.Fa rs_reaper
field of the structure is the pid of the reaper for passed process id.
.It Dv REAPER_STATUS_REALINIT
The specified process is the root of the reaper tree, i.e.
.Xr init 8.
.El
The
.Fa rs_children
returns the number of the children of the reaper.
The
.Fa rs_descendants
returns the total number of descendants of the reaper,
not counting descendants of the reapers in the subtree.
The
.Fa rs_reaper
returns the reaper pid.
The
.Fa rs_pid
returns pid of some reaper child if there is any descendant.
.It Dv PROC_REAP_GETPIDS
Queries the list of descendants of the reaper of the specified process.
The request takes the pointer to
.Vt "struct procctl_reaper_pids"
as
.Fa data .
.Bd -literal
struct procctl_reaper_pids {
u_int rp_count;
struct procctl_reaper_pidinfo *rp_pids;
};
.Ed
On call, the
.Fa rp_pids
must point to the array of
.Vt procctl_reaper_pidinfo
structures, to be filled on return,
and the
.Fa rp_count
must specify the size of the array,
no more than rp_count elements is filled by kernel.
.Pp
The
.Vt "struct procctl_reaper_pidinfo"
structure provides some information about one reaper' descendant.
Note that for the descendant which is not child, it is the subject
of usual race with process exiting and pid reuse.
.Bd -literal
struct procctl_reaper_pidinfo {
pid_t pi_pid;
pid_t pi_subtree;
u_int pi_flags;
};
.Ed
The
.Fa pi_pid
is the process id of the descendant.
The
.Fa pi_subtree
provides the pid of the child of the reaper, which is (grand-)parent
of the process.
The
.Fa pi_flags
returns the following flags, further describing the descendant:
.Bl -tag -width "Dv REAPER_PIDINFO_VALID"
.It Dv REAPER_PIDINFO_VALID
Set for the
.Vt procctl_reaper_pidinfo
structure, which was filled by kernel.
Zero-filling the
.Fa rp_pids
array and testing the flag allows the caller to detect the end
of returned array.
.It Dv REAPER_PIDINFO_CHILD
The
.Fa pi_pid
is the direct child of the reaper.
.El
.It Dv PROC_REAP_KILL
Request to deliver a signal to some subset of descendants of the reaper.
The
.Fa data
must point to
.Vt procctl_reaper_kill
structure, which is used both for parameters and status return.
.Bd -literal
struct procctl_reaper_kill {
int rk_sig;
u_int rk_flags;
pid_t rk_subtree;
u_int rk_killed;
pid_t rk_fpid;
};
.Ed
The
.Fa rk_sig
specifies the signal to be delivered.
Zero is not a valid signal number, unlike
.Xr kill 2 .
The
.Fa rk_flags
further directs the operation.
It is or-ed from the following flags:
.Bl -tag -width "Dv REAPER_KILL_CHILDREN"
.It Dv REAPER_KILL_CHILDREN
Deliver the specified signal only to direct children of the reaper.
.It Dv REAPER_KILL_SUBTREE
Deliver the specified signal only to descendants which were forked by
the direct child with pid specified in
.Fa rk_subtree .
.El
If no
.Dv REAPER_KILL_CHILDREN
and
.Dv REAPER_KILL_SUBTREE
flags are specified, all current descendants of the reaper are signalled.
.Pp
If signal was delivered to any process, the return value from the request
is zero.
In this case,
.Fa rk_killed
field is filled with the count of processes signalled.
The
.Fa rk_fpid
field is set to the pid of the first process for which signal
delivery failed, e.g. due to the permission problems.
If no such process exist, the
.Fa rk_fpid
is set to -1.
.El
.Sh RETURN VALUES
If an error occurs, a value of -1 is returned and
@ -132,11 +304,48 @@ An invalid operation or flag was passed in
for a
.Dv PROC_SPROTECT
command.
.It Bq Er EPERM
The
.Fa idtype
argument is not equal to
.Dv P_PID ,
or
.Fa id
is not equal to the pid of the calling process, for
.Dv PROC_REAP_ACQUIRE
or
.Dv PROC_REAP_RELEASE
requests.
.It Bq Er EINVAL
Invalid or undefined flags were passed to
.Dv PROC_REAP_KILL
request.
.It Bq Er EINVAL
Invalid or zero signal number was requested for
.Dv PROC_REAP_KILL
request.
.It Bq Er EINVAL
The
.Dv PROC_REAP_RELEASE
request was issued by the
.Xr init 8
process.
.It Bq Er EBUSY
The
.Dv PROC_REAP_ACQUIRE
request was issued by the process which already acquired reaper status
and did not released it.
.El
.Sh SEE ALSO
.Xr ptrace 2
.Xr kill 2 ,
.Xr ptrace 2 ,
.Xr wait 2 ,
.Xr init 8
.Sh HISTORY
The
.Fn procctl
function appeared in
.Fx 10.0 .
Reaper facility was created based on the similar feature of Linux and
DragonflyBSD, and first appeared in
.Fx 10.2 .

6
sys/compat/freebsd32/freebsd32.h
View File

@ -390,4 +390,10 @@ struct kld32_file_stat {
char pathname[MAXPATHLEN];
};
struct procctl_reaper_pids32 {
u_int rp_count;
u_int rp_pad0[15];
uint32_t rp_pids;
};
#endif /* !_COMPAT_FREEBSD32_FREEBSD32_H_ */

51
sys/compat/freebsd32/freebsd32_misc.c
View File

@ -2957,20 +2957,63 @@ int
freebsd32_procctl(struct thread *td, struct freebsd32_procctl_args *uap)
{
void *data;
int error, flags;
union {
struct procctl_reaper_status rs;
struct procctl_reaper_pids rp;
struct procctl_reaper_kill rk;
} x;
union {
struct procctl_reaper_pids32 rp;
} x32;
int error, error1, flags;
switch (uap->com) {
case PROC_SPROTECT:
error = copyin(PTRIN(uap->data), &flags, sizeof(flags));
if (error)
if (error != 0)
return (error);
data = &flags;
break;
case PROC_REAP_ACQUIRE:
case PROC_REAP_RELEASE:
if (uap->data != NULL)
return (EINVAL);
data = NULL;
break;
case PROC_REAP_STATUS:
data = &x.rs;
break;
case PROC_REAP_GETPIDS:
error = copyin(uap->data, &x32.rp, sizeof(x32.rp));
if (error != 0)
return (error);
CP(x32.rp, x.rp, rp_count);
PTRIN_CP(x32.rp, x.rp, rp_pids);
data = &x.rp;
break;
case PROC_REAP_KILL:
error = copyin(uap->data, &x.rk, sizeof(x.rk));
if (error != 0)
return (error);
data = &x.rk;
break;
default:
return (EINVAL);
}
return (kern_procctl(td, uap->idtype, PAIR32TO64(id_t, uap->id),
uap->com, data));
error = kern_procctl(td, uap->idtype, PAIR32TO64(id_t, uap->id),
uap->com, data);
switch (uap->com) {
case PROC_REAP_STATUS:
if (error == 0)
error = copyout(&x.rs, uap->data, sizeof(x.rs));
break;
case PROC_REAP_KILL:
error1 = copyout(&x.rk, uap->data, sizeof(x.rk));
if (error == 0)
error = error1;
break;
}
return (error);
}
int

1
sys/conf/files
View File

@ -2987,6 +2987,7 @@ kern/kern_pmc.c standard
kern/kern_poll.c optional device_polling
kern/kern_priv.c standard
kern/kern_proc.c standard
kern/kern_procctl.c standard
kern/kern_prot.c standard
kern/kern_racct.c standard
kern/kern_rangelock.c standard

7
sys/kern/init_main.c
View File

@ -496,7 +496,8 @@ proc0_init(void *dummy __unused)
prison0.pr_cpuset = cpuset_ref(td->td_cpuset);
p->p_peers = 0;
p->p_leader = p;
p->p_reaper = p;
LIST_INIT(&p->p_reaplist);
strncpy(p->p_comm, "kernel", sizeof (p->p_comm));
strncpy(td->td_name, "swapper", sizeof (td->td_name));
@ -821,8 +822,11 @@ create_init(const void *udata __unused)
KASSERT(initproc->p_pid == 1, ("create_init: initproc->p_pid != 1"));
/* divorce init's credentials from the kernel's */
newcred = crget();
sx_xlock(&proctree_lock);
PROC_LOCK(initproc);
initproc->p_flag |= P_SYSTEM | P_INMEM;
initproc->p_treeflag |= P_TREE_REAPER;
LIST_INSERT_HEAD(&initproc->p_reaplist, &proc0, p_reapsibling);
oldcred = initproc->p_ucred;
crcopy(newcred, oldcred);
#ifdef MAC
@ -833,6 +837,7 @@ create_init(const void *udata __unused)
#endif
initproc->p_ucred = newcred;
PROC_UNLOCK(initproc);
sx_xunlock(&proctree_lock);
crfree(oldcred);
cred_update_thread(FIRST_THREAD_IN_PROC(initproc));
cpu_set_fork_handler(FIRST_THREAD_IN_PROC(initproc), start_init, NULL);

39
sys/kern/kern_exit.c
View File

@ -123,6 +123,31 @@ proc_realparent(struct proc *child)
return (parent);
}
void
reaper_abandon_children(struct proc *p, bool exiting)
{
struct proc *p1, *p2, *ptmp;
sx_assert(&proctree_lock, SX_LOCKED);
KASSERT(p != initproc, ("reaper_abandon_children for initproc"));
if ((p->p_treeflag & P_TREE_REAPER) == 0)
return;
p1 = p->p_reaper;
LIST_FOREACH_SAFE(p2, &p->p_reaplist, p_reapsibling, ptmp) {
LIST_REMOVE(p2, p_reapsibling);
p2->p_reaper = p1;
p2->p_reapsubtree = p->p_reapsubtree;
LIST_INSERT_HEAD(&p1->p_reaplist, p2, p_reapsibling);
if (exiting && p2->p_pptr == p) {
PROC_LOCK(p2);
proc_reparent(p2, p1);
PROC_UNLOCK(p2);
}
}
KASSERT(LIST_EMPTY(&p->p_reaplist), ("p_reaplist not empty"));
p->p_treeflag &= ~P_TREE_REAPER;
}
static void
clear_orphan(struct proc *p)
{
@ -458,14 +483,14 @@ exit1(struct thread *td, int rv)
sx_xlock(&proctree_lock);
q = LIST_FIRST(&p->p_children);
if (q != NULL) /* only need this if any child is S_ZOMB */
wakeup(initproc);
wakeup(q->p_reaper);
for (; q != NULL; q = nq) {
nq = LIST_NEXT(q, p_sibling);
PROC_LOCK(q);
q->p_sigparent = SIGCHLD;
if (!(q->p_flag & P_TRACED)) {
proc_reparent(q, initproc);
proc_reparent(q, q->p_reaper);
} else {
/*
* Traced processes are killed since their existence
@ -473,7 +498,7 @@ exit1(struct thread *td, int rv)
*/
t = proc_realparent(q);
if (t == p) {
proc_reparent(q, initproc);
proc_reparent(q, q->p_reaper);
} else {
PROC_LOCK(t);
proc_reparent(q, t);
@ -562,7 +587,7 @@ exit1(struct thread *td, int rv)
mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx);
pp = p->p_pptr;
PROC_UNLOCK(pp);
proc_reparent(p, initproc);
proc_reparent(p, p->p_reaper);
p->p_sigparent = SIGCHLD;
PROC_LOCK(p->p_pptr);
@ -575,8 +600,8 @@ exit1(struct thread *td, int rv)
} else
mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx);
if (p->p_pptr == initproc)
kern_psignal(p->p_pptr, SIGCHLD);
if (p->p_pptr == p->p_reaper || p->p_pptr == initproc)
childproc_exited(p);
else if (p->p_sigparent != 0) {
if (p->p_sigparent == SIGCHLD)
childproc_exited(p);
@ -849,6 +874,8 @@ proc_reap(struct thread *td, struct proc *p, int *status, int options)
LIST_REMOVE(p, p_list); /* off zombproc */
sx_xunlock(&allproc_lock);
LIST_REMOVE(p, p_sibling);
reaper_abandon_children(p, true);
LIST_REMOVE(p, p_reapsibling);
PROC_LOCK(p);
clear_orphan(p);
PROC_UNLOCK(p);

24
sys/kern/kern_fork.c
View File

@ -261,11 +261,21 @@ fork_findpid(int flags)
* Scan the active and zombie procs to check whether this pid
* is in use. Remember the lowest pid that's greater
* than trypid, so we can avoid checking for a while.
*
* Avoid reuse of the process group id, session id or
* the reaper subtree id. Note that for process group
* and sessions, the amount of reserved pids is
* limited by process limit. For the subtree ids, the
* id is kept reserved only while there is a
* non-reaped process in the subtree, so amount of
* reserved pids is limited by process limit times
* two.
*/
p = LIST_FIRST(&allproc);
again:
for (; p != NULL; p = LIST_NEXT(p, p_list)) {
while (p->p_pid == trypid ||
p->p_reapsubtree == trypid ||
(p->p_pgrp != NULL &&
(p->p_pgrp->pg_id == trypid ||
(p->p_session != NULL &&
@ -611,12 +621,20 @@ do_fork(struct thread *td, int flags, struct proc *p2, struct thread *td2,
* of init. This effectively disassociates the child from the
* parent.
*/
if (flags & RFNOWAIT)
pptr = initproc;
else
if ((flags & RFNOWAIT) != 0) {
pptr = p1->p_reaper;
p2->p_reaper = pptr;
} else {
p2->p_reaper = (p1->p_treeflag & P_TREE_REAPER) != 0 ?
p1 : p1->p_reaper;
pptr = p1;
}
p2->p_pptr = pptr;
LIST_INSERT_HEAD(&pptr->p_children, p2, p_sibling);
LIST_INIT(&p2->p_reaplist);
LIST_INSERT_HEAD(&p2->p_reaper->p_reaplist, p2, p_reapsibling);
if (p2->p_reaper == p1)
p2->p_reapsubtree = p2->p_pid;
sx_xunlock(&proctree_lock);
/* Inform accounting that we have forked. */

460
sys/kern/kern_procctl.c Normal file
View File

@ -0,0 +1,460 @@
/*-
* Copyright (c) 2014 John Baldwin
* Copyright (c) 2014 The FreeBSD Foundation
*
* Portions of this software were developed by Konstantin Belousov
* under sponsorship from the FreeBSD Foundation.
*
* 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/param.h>
#include <sys/systm.h>
#include <sys/capsicum.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/priv.h>
#include <sys/proc.h>
#include <sys/procctl.h>
#include <sys/sx.h>
#include <sys/syscallsubr.h>
#include <sys/sysproto.h>
#include <sys/wait.h>
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_cansched(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);
}
static int
reap_acquire(struct thread *td, struct proc *p)
{
sx_assert(&proctree_lock, SX_XLOCKED);
if (p != curproc)
return (EPERM);
if ((p->p_treeflag & P_TREE_REAPER) != 0)
return (EBUSY);
p->p_treeflag |= P_TREE_REAPER;
/*
* We do not reattach existing children and the whole tree
* under them to us, since p->p_reaper already seen them.
*/
return (0);
}
static int
reap_release(struct thread *td, struct proc *p)
{
sx_assert(&proctree_lock, SX_XLOCKED);
if (p != curproc)
return (EPERM);
if (p == initproc)
return (EINVAL);
if ((p->p_treeflag & P_TREE_REAPER) == 0)
return (EINVAL);
reaper_abandon_children(p, false);
return (0);
}
static int
reap_status(struct thread *td, struct proc *p,
struct procctl_reaper_status *rs)
{
struct proc *reap, *p2;
sx_assert(&proctree_lock, SX_LOCKED);
bzero(rs, sizeof(*rs));
if ((p->p_treeflag & P_TREE_REAPER) == 0) {
reap = p->p_reaper;
} else {
reap = p;
rs->rs_flags |= REAPER_STATUS_OWNED;
}
if (reap == initproc)
rs->rs_flags |= REAPER_STATUS_REALINIT;
rs->rs_reaper = reap->p_pid;
rs->rs_descendants = 0;
rs->rs_children = 0;
if (!LIST_EMPTY(&reap->p_reaplist)) {
KASSERT(!LIST_EMPTY(&reap->p_children), ("no children"));
rs->rs_pid = LIST_FIRST(&reap->p_children)->p_pid;
LIST_FOREACH(p2, &reap->p_reaplist, p_reapsibling) {
if (proc_realparent(p2) == reap)
rs->rs_children++;
rs->rs_descendants++;
}
} else {
rs->rs_pid = -1;
KASSERT(LIST_EMPTY(&reap->p_reaplist), ("reap children list"));
KASSERT(LIST_EMPTY(&reap->p_children), ("children list"));
}
return (0);
}
static int
reap_getpids(struct thread *td, struct proc *p, struct procctl_reaper_pids *rp)
{
struct proc *reap, *p2;
struct procctl_reaper_pidinfo *pi, *pip;
u_int i, n;
int error;
sx_assert(&proctree_lock, SX_LOCKED);
PROC_UNLOCK(p);
reap = (p->p_treeflag & P_TREE_REAPER) == 0 ? p->p_reaper : p;
n = i = 0;
error = 0;
LIST_FOREACH(p2, &reap->p_reaplist, p_reapsibling)
n++;
sx_unlock(&proctree_lock);
if (rp->rp_count < n)
n = rp->rp_count;
pi = malloc(n * sizeof(*pi), M_TEMP, M_WAITOK);
sx_slock(&proctree_lock);
LIST_FOREACH(p2, &reap->p_reaplist, p_reapsibling) {
if (i == n)
break;
pip = &pi[i];
bzero(pip, sizeof(*pip));
pip->pi_pid = p2->p_pid;
pip->pi_subtree = p2->p_reapsubtree;
pip->pi_flags = REAPER_PIDINFO_VALID;
if (proc_realparent(p2) == reap)
pip->pi_flags |= REAPER_PIDINFO_CHILD;
i++;
}
sx_sunlock(&proctree_lock);
error = copyout(pi, rp->rp_pids, i * sizeof(*pi));
free(pi, M_TEMP);
sx_slock(&proctree_lock);
PROC_LOCK(p);
return (error);
}
static int
reap_kill(struct thread *td, struct proc *p, struct procctl_reaper_kill *rk)
{
struct proc *reap, *p2;
ksiginfo_t ksi;
int error, error1;
sx_assert(&proctree_lock, SX_LOCKED);
PROC_UNLOCK(p);
if (IN_CAPABILITY_MODE(td))
return (ECAPMODE);
if (rk->rk_sig <= 0 || rk->rk_sig > _SIG_MAXSIG)
return (EINVAL);
if ((rk->rk_flags & ~REAPER_KILL_CHILDREN) != 0)
return (EINVAL);
reap = (p->p_treeflag & P_TREE_REAPER) == 0 ? p->p_reaper : p;
ksiginfo_init(&ksi);
ksi.ksi_signo = rk->rk_sig;
ksi.ksi_code = SI_USER;
ksi.ksi_pid = td->td_proc->p_pid;
ksi.ksi_uid = td->td_ucred->cr_ruid;
error = ESRCH;
rk->rk_killed = 0;
rk->rk_fpid = -1;
for (p2 = (rk->rk_flags & REAPER_KILL_CHILDREN) != 0 ?
LIST_FIRST(&reap->p_children) : LIST_FIRST(&reap->p_reaplist);
p2 != NULL;
p2 = (rk->rk_flags & REAPER_KILL_CHILDREN) != 0 ?
LIST_NEXT(p2, p_sibling) : LIST_NEXT(p2, p_reapsibling)) {
if ((rk->rk_flags & REAPER_KILL_SUBTREE) != 0 &&
p2->p_reapsubtree != rk->rk_subtree)
continue;
PROC_LOCK(p2);
error1 = p_cansignal(td, p2, rk->rk_sig);
if (error1 == 0) {
pksignal(p2, rk->rk_sig, &ksi);
rk->rk_killed++;
error = error1;
} else if (error == ESRCH) {
error = error1;
rk->rk_fpid = p2->p_pid;
}
PROC_UNLOCK(p2);
/* Do not end the loop on error, signal everything we can. */
}
PROC_LOCK(p);
return (error);
}
#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)
{
void *data;
union {
struct procctl_reaper_status rs;
struct procctl_reaper_pids rp;
struct procctl_reaper_kill rk;
} x;
int error, error1, flags;
switch (uap->com) {
case PROC_SPROTECT:
error = copyin(uap->data, &flags, sizeof(flags));
if (error != 0)
return (error);
data = &flags;
break;
case PROC_REAP_ACQUIRE:
case PROC_REAP_RELEASE:
if (uap->data != NULL)
return (EINVAL);
data = NULL;
break;
case PROC_REAP_STATUS:
data = &x.rs;
break;
case PROC_REAP_GETPIDS:
error = copyin(uap->data, &x.rp, sizeof(x.rp));
if (error != 0)
return (error);
data = &x.rp;
break;
case PROC_REAP_KILL:
error = copyin(uap->data, &x.rk, sizeof(x.rk));
if (error != 0)
return (error);
data = &x.rk;
break;
default:
return (EINVAL);
}
error = kern_procctl(td, uap->idtype, uap->id, uap->com, data);
switch (uap->com) {
case PROC_REAP_STATUS:
if (error == 0)
error = copyout(&x.rs, uap->data, sizeof(x.rs));
case PROC_REAP_KILL:
error1 = copyout(&x.rk, uap->data, sizeof(x.rk));
if (error == 0)
error = error1;
break;
}
return (error);
}
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));
case PROC_REAP_ACQUIRE:
return (reap_acquire(td, p));
case PROC_REAP_RELEASE:
return (reap_release(td, p));
case PROC_REAP_STATUS:
return (reap_status(td, p, data));
case PROC_REAP_GETPIDS:
return (reap_getpids(td, p, data));
case PROC_REAP_KILL:
return (reap_kill(td, p, 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;
switch (com) {
case PROC_REAP_ACQUIRE:
case PROC_REAP_RELEASE:
case PROC_REAP_STATUS:
case PROC_REAP_GETPIDS:
case PROC_REAP_KILL:
if (idtype != P_PID)
return (EINVAL);
}
switch (com) {
case PROC_SPROTECT:
case PROC_REAP_STATUS:
case PROC_REAP_GETPIDS:
case PROC_REAP_KILL:
sx_slock(&proctree_lock);
break;
case PROC_REAP_ACQUIRE:
case PROC_REAP_RELEASE:
sx_xlock(&proctree_lock);
break;
default:
return (EINVAL);
}
switch (idtype) {
case P_PID:
p = pfind(id);
if (p == NULL) {
error = ESRCH;
break;
}
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_unlock(&proctree_lock);
return (error);
}

191
sys/kern/sys_process.c
View File

@ -43,7 +43,6 @@ __FBSDID("$FreeBSD$");
#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>
@ -1234,193 +1233,3 @@ 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_cansched(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;
}
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);
}

10
sys/sys/proc.h
View File

@ -513,6 +513,11 @@ struct proc {
struct proc *p_pptr; /* (c + e) Pointer to parent process. */
LIST_ENTRY(proc) p_sibling; /* (e) List of sibling processes. */
LIST_HEAD(, proc) p_children; /* (e) Pointer to list of children. */
struct proc *p_reaper; /* (e) My reaper. */
LIST_HEAD(, proc) p_reaplist; /* (e) List of my descendants
(if I am reaper). */
LIST_ENTRY(proc) p_reapsibling; /* (e) List of siblings - descendants of
the same reaper. */
struct mtx p_mtx; /* (n) Lock for this struct. */
struct mtx p_statmtx; /* Lock for the stats */
struct mtx p_itimmtx; /* Lock for the virt/prof timers */
@ -570,6 +575,9 @@ struct proc {
rlim_t p_cpulimit; /* (c) Current CPU limit in seconds. */
signed char p_nice; /* (c) Process "nice" value. */
int p_fibnum; /* in this routing domain XXX MRT */
pid_t p_reapsubtree; /* (e) Pid of the direct child of the
reaper which spawned
our subtree. */
/* End area that is copied on creation. */
#define p_endcopy p_xstat
@ -671,6 +679,7 @@ struct proc {
#define P_TREE_ORPHANED 0x00000001 /* Reparented, on orphan list */
#define P_TREE_FIRST_ORPHAN 0x00000002 /* First element of orphan
list */
#define P_TREE_REAPER 0x00000004 /* Reaper of subtree */
/*
* These were process status values (p_stat), now they are only used in
@ -920,6 +929,7 @@ void proc_reparent(struct proc *child, struct proc *newparent);
struct pstats *pstats_alloc(void);
void pstats_fork(struct pstats *src, struct pstats *dst);
void pstats_free(struct pstats *ps);
void reaper_abandon_children(struct proc *p, bool exiting);
int securelevel_ge(struct ucred *cr, int level);
int securelevel_gt(struct ucred *cr, int level);
void sess_hold(struct session *);

57
sys/sys/procctl.h
View File

@ -30,7 +30,17 @@
#ifndef _SYS_PROCCTL_H_
#define _SYS_PROCCTL_H_
#ifndef _KERNEL
#include <sys/types.h>
#include <sys/wait.h>
#endif
#define PROC_SPROTECT 1 /* set protected state */
#define PROC_REAP_ACQUIRE 2 /* reaping enable */
#define PROC_REAP_RELEASE 3 /* reaping disable */
#define PROC_REAP_STATUS 4 /* reaping status */
#define PROC_REAP_GETPIDS 5 /* get descendants */
#define PROC_REAP_KILL 6 /* kill descendants */
/* Operations for PROC_SPROTECT (passed in integer arg). */
#define PPROT_OP(x) ((x) & 0xf)
@ -42,10 +52,51 @@
#define PPROT_DESCEND 0x10
#define PPROT_INHERIT 0x20
#ifndef _KERNEL
#include <sys/types.h>
#include <sys/wait.h>
/* Result of PREAP_STATUS (returned by value). */
struct procctl_reaper_status {
u_int rs_flags;
u_int rs_children;
u_int rs_descendants;
pid_t rs_reaper;
pid_t rs_pid;
u_int rs_pad0[15];
};
/* struct procctl_reaper_status rs_flags */
#define REAPER_STATUS_OWNED 0x00000001
#define REAPER_STATUS_REALINIT 0x00000002
struct procctl_reaper_pidinfo {
pid_t pi_pid;
pid_t pi_subtree;
u_int pi_flags;
u_int pi_pad0[15];
};
#define REAPER_PIDINFO_VALID 0x00000001
#define REAPER_PIDINFO_CHILD 0x00000002
struct procctl_reaper_pids {
u_int rp_count;
u_int rp_pad0[15];
struct procctl_reaper_pidinfo *rp_pids;
};
struct procctl_reaper_kill {
int rk_sig; /* in - signal to send */
u_int rk_flags; /* in - REAPER_KILL flags */
pid_t rk_subtree; /* in - subtree, if REAPER_KILL_SUBTREE */
u_int rk_killed; /* out - count of processes sucessfully
killed */
pid_t rk_fpid; /* out - first failed pid for which error
is returned */
u_int rk_pad0[15];
};
#define REAPER_KILL_CHILDREN 0x00000001
#define REAPER_KILL_SUBTREE 0x00000002
#ifndef _KERNEL
__BEGIN_DECLS
int procctl(idtype_t, id_t, int, void *);
__END_DECLS