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Add experimental support for process descriptors

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A "process descriptor" file descriptor is used to manage processes
without using the PID namespace. This is required for Capsicum's
Capability Mode, where the PID namespace is unavailable.

New system calls pdfork(2) and pdkill(2) offer the functional equivalents
of fork(2) and kill(2). pdgetpid(2) allows querying the PID of the remote
process for debugging purposes. The currently-unimplemented pdwait(2) will,
in the future, allow querying rusage/exit status. In the interim, poll(2)
may be used to check (and wait for) process termination.

When a process is referenced by a process descriptor, it does not issue
SIGCHLD to the parent, making it suitable for use in libraries---a common
scenario when using library compartmentalisation from within large
applications (such as web browsers). Some observers may note a similarity
to Mach task ports; process descriptors provide a subset of this behaviour,
but in a UNIX style.

This feature is enabled by "options PROCDESC", but as with several other
Capsicum kernel features, is not enabled by default in GENERIC 9.0.

Reviewed by: jhb, kib
Approved by: re (kib), mentor (rwatson)
Sponsored by: Google Inc
This commit is contained in:
Jonathan Anderson 2011-08-18 22:51:30 +00:00
parent f55d3fbe84
commit cfb5f76865
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=224987
23 changed files with 1074 additions and 53 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
lib/libc/sys/Makefile.inc
View File

@ -96,7 +96,7 @@ MAN+= abort2.2 accept.2 access.2 acct.2 adjtime.2 \
mq_setattr.2 \
msgctl.2 msgget.2 msgrcv.2 msgsnd.2 \
msync.2 munmap.2 nanosleep.2 nfssvc.2 ntp_adjtime.2 open.2 \
pathconf.2 pipe.2 poll.2 posix_fallocate.2 posix_openpt.2 profil.2 \
pathconf.2 pdfork.2 pipe.2 poll.2 posix_fallocate.2 posix_openpt.2 profil.2 \
pselect.2 ptrace.2 quotactl.2 \
read.2 readlink.2 reboot.2 recv.2 rename.2 revoke.2 rfork.2 rmdir.2 \
rtprio.2
@ -178,6 +178,9 @@ MLINKS+=ntp_adjtime.2 ntp_gettime.2
MLINKS+=open.2 openat.2
MLINKS+=pathconf.2 fpathconf.2
MLINKS+=pathconf.2 lpathconf.2
MLINKS+=pdfork.2 pdgetpid.2\
pdfork.2 pdkill.2 \
pdfork.2 pdwait4.2
MLINKS+=read.2 pread.2 read.2 preadv.2 read.2 readv.2
MLINKS+=readlink.2 readlinkat.2
MLINKS+=recv.2 recvfrom.2 recv.2 recvmsg.2

3
lib/libc/sys/Symbol.map
View File

@ -366,6 +366,9 @@ FBSD_1.2 {
cap_new;
cap_getrights;
getloginclass;
pdfork;
pdgetpid;
pdkill;
posix_fallocate;
rctl_get_racct;
rctl_get_rules;

4
lib/libc/sys/cap_new.2
View File

@ -260,7 +260,7 @@ Permit
.Xr pdkill 2 .
.It Dv CAP_PDWAIT
Permit
.Xr pdwait 2 .
.Xr pdwait4 2 .
.It Dv CAP_PEELOFF
Permit
.Xr sctp_peeloff 2 .
@ -429,7 +429,7 @@ argument is not a capability.
.Xr openat 2 ,
.Xr pdgetpid 2 ,
.Xr pdkill 2 ,
.Xr pdwait 2 ,
.Xr pdwait4 2 ,
.Xr pipe 2 ,
.Xr poll 2 ,
.Xr pread 2 ,

182
lib/libc/sys/pdfork.2 Normal file
View File

@ -0,0 +1,182 @@
.\"
.\" Copyright (c) 2009-2010 Robert N. M. Watson
.\" All rights reserved.
.\"
.\" This software was developed at the University of Cambridge Computer
.\" Laboratory with support from a grant from Google, 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.
.\"
.\" 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 August 16, 2011
.Dt PDFORK 2
.Os
.Sh NAME
.Nm pdfork ,
.Nm pdgetpid ,
.Nm pdkill ,
.Nm pdwait4
.Nd System calls to manage process descriptors
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In sys/procdesc.h
.Ft int
.Fn pdfork "int *fdp" "int flags"
.Ft int
.Fn pdgetpid "int fd" "pid_t *pidp"
.Ft int
.Fn pdkill "int fd" "int signum"
.Ft int
.Fn pdwait4 "int fd" "int *status" "int options" "struct rusage *rusage"
.Sh DESCRIPTION
Process descriptors are special file descriptors that represent processes,
and are created using
.Fn pdfork ,
a variant of
.Xr fork 2 ,
which, if successful, returns a process descriptor in the integer pointed to
by
.Fa pidp .
Processes created via
.Fn pdfork
will not cause
.Dv SIGCHLD
on termination.
.Fn pdfork
can accept the flags:
.Bl -tag -width ".Dv PD_DAEMON"
.It Dv PD_DAEMON
Instead of the default terminate-on-close behaviour, allow the process to
live until it is explicitly killed with
.Xr kill 2 .
.Pp
This option is not permitted in Capsicum capability mode (see
.Xr cap_enter 2 ) .
.El
.Pp
.Fn pdgetpid
queries the process ID (PID) if the process descriptor
.Fa fd .
.Pp
.Fn pdkill
is functionally identical to
.Xr kill 2 ,
except that it accepts a process descriptor,
.Fa fd ,
rather than a PID.
.Pp
.Fn pdwait4
behaves identially to
.Xr wait4 2 ,
but operates with respect to a process descriptor argument rather than a PID.
.Pp
The following system calls also have effects specific to process descriptors:
.Pp
.Xr fstat 2
queries status of a process descriptor; currently only the
.Fa st_mode ,
.Fa st_birthtime ,
.Fa st_atime ,
.Fa st_ctime
and
.Fa st_mtime
fields are defined. If the owner read, write, and execute bits are set then the
process represented by the process descriptor is still alive.
.Pp
.Xr poll 2
and
.Xr select 2
allow waiting for process state transitions; currently only
.Dv POLLHUP
is defined, and will be raised when the process dies.
.Pp
.Xr close 2
will close the process descriptor unless
.Dv PD_DAEMON
is set; if the process is still alive and this is
the last reference to the process descriptor, the process will be terminated
with the signal
.Dv SIGKILL .
.Sh RETURN VALUES
.Fn pdfork
returns a PID, 0 or -1, as
.Xr fork 2
does.
.Pp
.Fn pdgetpid
and
.Fn pdkill
return 0 on success and -1 on failure.
.Pp
.Fn pdwait4
returns a PID on success and -1 on failure.
.Sh ERRORS
These functions may return the same error numbers as their PID-based equivalents
(e.g.
.Fn pdfork
may return the same error numbers as
.Xr fork 2 ) ,
with the following additions:
.Bl -tag -width Er
.It Bq Er EINVAL
The signal number given to
.Fn pdkill
is invalid.
.It Bq Er ENOTCAPABLE
The process descriptor being operated on has insufficient rights (e.g.
.Dv CAP_PDKILL
for
.Fn pdkill ) .
.El
.Sh SEE ALSO
.Xr close 2 ,
.Xr fork 2 ,
.Xr fstat 2 ,
.Xr kill 2 ,
.Xr poll 2 ,
.Xr wait4 2
.Sh HISTORY
The
.Fn pdfork ,
.Fn pdgetpid ,
.Fn pdkill
and
.Fn pdwait4
system calls first appeared in
.Fx 9.0 .
.Pp
Support for process descriptors mode was developed as part of the
.Tn TrustedBSD
Project.
.Sh AUTHORS
.An -nosplit
These functions and the capability facility were created by
.An "Robert N. M. Watson" Aq rwatson@FreeBSD.org
and
.An "Jonathan Anderson" Aq jonathan@FreeBSD.org
at the University of Cambridge Computer Laboratory with support from a grant
from Google, Inc.
.Sh BUGS
.Fn pdwait4
has not yet been implemented.

8
sys/compat/linux/linux_fork.c
View File

@ -64,7 +64,8 @@ linux_fork(struct thread *td, struct linux_fork_args *args)
printf(ARGS(fork, ""));
#endif
if ((error = fork1(td, RFFDG | RFPROC | RFSTOPPED, 0, &p2)) != 0)
if ((error = fork1(td, RFFDG | RFPROC | RFSTOPPED, 0, &p2, NULL, 0))
!= 0)
return (error);
td->td_retval[0] = p2->p_pid;
@ -100,7 +101,8 @@ linux_vfork(struct thread *td, struct linux_vfork_args *args)
#endif
/* Exclude RFPPWAIT */
if ((error = fork1(td, RFFDG | RFPROC | RFMEM | RFSTOPPED, 0, &p2)) != 0)
if ((error = fork1(td, RFFDG | RFPROC | RFMEM | RFSTOPPED, 0, &p2,
NULL, 0)) != 0)
return (error);
td->td_retval[0] = p2->p_pid;
@ -190,7 +192,7 @@ linux_clone(struct thread *td, struct linux_clone_args *args)
if (args->parent_tidptr == NULL)
return (EINVAL);
error = fork1(td, ff, 0, &p2);
error = fork1(td, ff, 0, &p2, NULL, 0);
if (error)
return (error);

3
sys/conf/NOTES
View File

@ -1159,6 +1159,9 @@ options MAC_TEST
options CAPABILITIES # fine-grained rights on file descriptors
options CAPABILITY_MODE # sandboxes with no global namespace access
# Support for process descriptors
options PROCDESC
#####################################################################
# CLOCK OPTIONS

1
sys/conf/files
View File

@ -2412,6 +2412,7 @@ kern/subr_witness.c optional witness
kern/sys_capability.c standard
kern/sys_generic.c standard
kern/sys_pipe.c standard
kern/sys_procdesc.c standard
kern/sys_process.c standard
kern/sys_socket.c standard
kern/syscalls.c standard

1
sys/conf/options
View File

@ -149,6 +149,7 @@ PPC_DEBUG opt_ppc.h
PPC_PROBE_CHIPSET opt_ppc.h
PPS_SYNC opt_ntp.h
PREEMPTION opt_sched.h
PROCDESC opt_procdesc.h
QUOTA
SCHED_4BSD opt_sched.h
SCHED_STATS opt_sched.h

2
sys/kern/capabilities.conf
View File

@ -475,7 +475,7 @@ openbsd_poll
pdfork
pdgetpid
pdkill
pdwait4
#pdwait4 # not yet implemented
##
## Allow pipe(2).

3
sys/kern/init_main.c
View File

@ -790,7 +790,8 @@ create_init(const void *udata __unused)
struct ucred *newcred, *oldcred;
int error;
error = fork1(&thread0, RFFDG | RFPROC | RFSTOPPED, 0, &initproc);
error = fork1(&thread0, RFFDG | RFPROC | RFSTOPPED, 0, &initproc,
NULL, 0);
if (error)
panic("cannot fork init: %d\n", error);
KASSERT(initproc->p_pid == 1, ("create_init: initproc->p_pid != 1"));

30
sys/kern/kern_descrip.c
View File

@ -41,6 +41,7 @@ __FBSDID("$FreeBSD$");
#include "opt_compat.h"
#include "opt_ddb.h"
#include "opt_ktrace.h"
#include "opt_procdesc.h"
#include <sys/param.h>
#include <sys/systm.h>
@ -65,6 +66,7 @@ __FBSDID("$FreeBSD$");
#include <sys/pipe.h>
#include <sys/priv.h>
#include <sys/proc.h>
#include <sys/procdesc.h>
#include <sys/protosw.h>
#include <sys/racct.h>
#include <sys/resourcevar.h>
@ -120,6 +122,8 @@ static int fill_vnode_info(struct vnode *vp, struct kinfo_file *kif);
static int fill_socket_info(struct socket *so, struct kinfo_file *kif);
static int fill_pts_info(struct tty *tp, struct kinfo_file *kif);
static int fill_pipe_info(struct pipe *pi, struct kinfo_file *kif);
static int fill_procdesc_info(struct procdesc *pdp,
struct kinfo_file *kif);
/*
* A process is initially started out with NDFILE descriptors stored within
@ -3056,6 +3060,12 @@ sysctl_kern_proc_ofiledesc(SYSCTL_HANDLER_ARGS)
tp = fp->f_data;
break;
#ifdef PROCDESC
case DTYPE_PROCDESC:
kif->kf_type = KF_TYPE_PROCDESC;
break;
#endif
default:
kif->kf_type = KF_TYPE_UNKNOWN;
break;
@ -3218,6 +3228,9 @@ export_fd_for_sysctl(void *data, int type, int fd, int fflags, int refcnt,
case KF_TYPE_PTS:
error = fill_pts_info((struct tty *)data, kif);
break;
case KF_TYPE_PROCDESC:
error = fill_procdesc_info((struct procdesc *)data, kif);
break;
default:
error = 0;
}
@ -3391,6 +3404,13 @@ sysctl_kern_proc_filedesc(SYSCTL_HANDLER_ARGS)
data = fp->f_data;
break;
#ifdef PROCDESC
case DTYPE_PROCDESC:
type = KF_TYPE_PROCDESC;
data = fp->f_data;
break;
#endif
default:
type = KF_TYPE_UNKNOWN;
break;
@ -3586,6 +3606,16 @@ fill_pipe_info(struct pipe *pi, struct kinfo_file *kif)
return (0);
}
static int
fill_procdesc_info(struct procdesc *pdp, struct kinfo_file *kif)
{
if (pdp == NULL)
return (1);
kif->kf_un.kf_proc.kf_pid = pdp->pd_pid;
return (0);
}
static SYSCTL_NODE(_kern_proc, KERN_PROC_FILEDESC, filedesc, CTLFLAG_RD,
sysctl_kern_proc_filedesc, "Process filedesc entries");

82
sys/kern/kern_exit.c
View File

@ -40,16 +40,19 @@ __FBSDID("$FreeBSD$");
#include "opt_compat.h"
#include "opt_kdtrace.h"
#include "opt_ktrace.h"
#include "opt_procdesc.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/sysproto.h>
#include <sys/capability.h>
#include <sys/eventhandler.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/procdesc.h>
#include <sys/pioctl.h>
#include <sys/jail.h>
#include <sys/tty.h>
@ -461,39 +464,54 @@ exit1(struct thread *td, int rv)
knlist_clear(&p->p_klist, 1);
/*
* Notify parent that we're gone. If parent has the PS_NOCLDWAIT
* flag set, or if the handler is set to SIG_IGN, notify process
* 1 instead (and hope it will handle this situation).
* If this is a process with a descriptor, we may not need to deliver
* a signal to the parent. proctree_lock is held over
* procdesc_exit() to serialize concurrent calls to close() and
* exit().
*/
PROC_LOCK(p->p_pptr);
mtx_lock(&p->p_pptr->p_sigacts->ps_mtx);
if (p->p_pptr->p_sigacts->ps_flag & (PS_NOCLDWAIT | PS_CLDSIGIGN)) {
struct proc *pp;
mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx);
pp = p->p_pptr;
PROC_UNLOCK(pp);
proc_reparent(p, initproc);
p->p_sigparent = SIGCHLD;
PROC_LOCK(p->p_pptr);
#ifdef PROCDESC
if (p->p_procdesc == NULL || procdesc_exit(p)) {
#endif
/*
* Notify parent, so in case he was wait(2)ing or
* executing waitpid(2) with our pid, he will
* continue.
* Notify parent that we're gone. If parent has the
* PS_NOCLDWAIT flag set, or if the handler is set to SIG_IGN,
* notify process 1 instead (and hope it will handle this
* situation).
*/
wakeup(pp);
} else
mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx);
PROC_LOCK(p->p_pptr);
mtx_lock(&p->p_pptr->p_sigacts->ps_mtx);
if (p->p_pptr->p_sigacts->ps_flag &
(PS_NOCLDWAIT | PS_CLDSIGIGN)) {
struct proc *pp;
if (p->p_pptr == initproc)
psignal(p->p_pptr, SIGCHLD);
else if (p->p_sigparent != 0) {
if (p->p_sigparent == SIGCHLD)
childproc_exited(p);
else /* LINUX thread */
psignal(p->p_pptr, p->p_sigparent);
}
mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx);
pp = p->p_pptr;
PROC_UNLOCK(pp);
proc_reparent(p, initproc);
p->p_sigparent = SIGCHLD;
PROC_LOCK(p->p_pptr);
/*
* Notify parent, so in case he was wait(2)ing or
* executing waitpid(2) with our pid, he will
* continue.
*/
wakeup(pp);
} else
mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx);
if (p->p_pptr == initproc)
psignal(p->p_pptr, SIGCHLD);
else if (p->p_sigparent != 0) {
if (p->p_sigparent == SIGCHLD)
childproc_exited(p);
else /* LINUX thread */
psignal(p->p_pptr, p->p_sigparent);
}
#ifdef PROCDESC
} else
PROC_LOCK(p->p_pptr);
#endif
sx_xunlock(&proctree_lock);
/*
@ -660,7 +678,7 @@ wait4(struct thread *td, struct wait_args *uap)
* rusage. Asserts and will release both the proctree_lock and the process
* lock as part of its work.
*/
static void
void
proc_reap(struct thread *td, struct proc *p, int *status, int options,
struct rusage *rusage)
{
@ -722,6 +740,10 @@ proc_reap(struct thread *td, struct proc *p, int *status, int options,
sx_xunlock(&allproc_lock);
LIST_REMOVE(p, p_sibling);
leavepgrp(p);
#ifdef PROCDESC
if (p->p_procdesc != NULL)
procdesc_reap(p);
#endif
sx_xunlock(&proctree_lock);
/*

96
sys/kern/kern_fork.c
View File

@ -40,11 +40,13 @@ __FBSDID("$FreeBSD$");
#include "opt_kdtrace.h"
#include "opt_ktrace.h"
#include "opt_kstack_pages.h"
#include "opt_procdesc.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/sysproto.h>
#include <sys/eventhandler.h>
#include <sys/fcntl.h>
#include <sys/filedesc.h>
#include <sys/jail.h>
#include <sys/kernel.h>
@ -55,6 +57,7 @@ __FBSDID("$FreeBSD$");
#include <sys/mutex.h>
#include <sys/priv.h>
#include <sys/proc.h>
#include <sys/procdesc.h>
#include <sys/pioctl.h>
#include <sys/racct.h>
#include <sys/resourcevar.h>
@ -104,7 +107,7 @@ fork(struct thread *td, struct fork_args *uap)
int error;
struct proc *p2;
error = fork1(td, RFFDG | RFPROC, 0, &p2);
error = fork1(td, RFFDG | RFPROC, 0, &p2, NULL, 0);
if (error == 0) {
td->td_retval[0] = p2->p_pid;
td->td_retval[1] = 0;
@ -112,6 +115,34 @@ fork(struct thread *td, struct fork_args *uap)
return (error);
}
/* ARGUSED */
int
pdfork(td, uap)
struct thread *td;
struct pdfork_args *uap;
{
#ifdef PROCDESC
int error, fd;
struct proc *p2;
/*
* It is necessary to return fd by reference because 0 is a valid file
* descriptor number, and the child needs to be able to distinguish
* itself from the parent using the return value.
*/
error = fork1(td, RFFDG | RFPROC | RFPROCDESC, 0, &p2,
&fd, uap->flags);
if (error == 0) {
td->td_retval[0] = p2->p_pid;
td->td_retval[1] = 0;
error = copyout(&fd, uap->fdp, sizeof(fd));
}
return (error);
#else
return (ENOSYS);
#endif
}
/* ARGSUSED */
int
vfork(struct thread *td, struct vfork_args *uap)
@ -124,7 +155,7 @@ vfork(struct thread *td, struct vfork_args *uap)
#else
flags = RFFDG | RFPROC | RFPPWAIT | RFMEM;
#endif
error = fork1(td, flags, 0, &p2);
error = fork1(td, flags, 0, &p2, NULL, 0);
if (error == 0) {
td->td_retval[0] = p2->p_pid;
td->td_retval[1] = 0;
@ -143,7 +174,7 @@ rfork(struct thread *td, struct rfork_args *uap)
return (EINVAL);
AUDIT_ARG_FFLAGS(uap->flags);
error = fork1(td, uap->flags, 0, &p2);
error = fork1(td, uap->flags, 0, &p2, NULL, 0);
if (error == 0) {
td->td_retval[0] = p2 ? p2->p_pid : 0;
td->td_retval[1] = 0;
@ -337,7 +368,7 @@ fork_norfproc(struct thread *td, int flags)
static void
do_fork(struct thread *td, int flags, struct proc *p2, struct thread *td2,
struct vmspace *vm2)
struct vmspace *vm2, int pdflags)
{
struct proc *p1, *pptr;
int p2_held, trypid;
@ -625,6 +656,16 @@ do_fork(struct thread *td, int flags, struct proc *p2, struct thread *td2,
p2->p_vmspace->vm_ssize);
}
#ifdef PROCDESC
/*
* Associate the process descriptor with the process before anything
* can happen that might cause that process to need the descriptor.
* However, don't do this until after fork(2) can no longer fail.
*/
if (flags & RFPROCDESC)
procdesc_new(p2, pdflags);
#endif
/*
* Both processes are set up, now check if any loadable modules want
* to adjust anything.
@ -710,7 +751,8 @@ do_fork(struct thread *td, int flags, struct proc *p2, struct thread *td2,
}
int
fork1(struct thread *td, int flags, int pages, struct proc **procp)
fork1(struct thread *td, int flags, int pages, struct proc **procp,
int *procdescp, int pdflags)
{
struct proc *p1;
struct proc *newproc;
@ -721,6 +763,9 @@ fork1(struct thread *td, int flags, int pages, struct proc **procp)
int error;
static int curfail;
static struct timeval lastfail;
#ifdef PROCDESC
struct file *fp_procdesc = NULL;
#endif
/* Check for the undefined or unimplemented flags. */
if ((flags & ~(RFFLAGS | RFTSIGFLAGS(RFTSIGMASK))) != 0)
@ -738,6 +783,18 @@ fork1(struct thread *td, int flags, int pages, struct proc **procp)
if ((flags & RFTSIGZMB) != 0 && (u_int)RFTSIGNUM(flags) > _SIG_MAXSIG)
return (EINVAL);
#ifdef PROCDESC
if ((flags & RFPROCDESC) != 0) {
/* Can't not create a process yet get a process descriptor. */
if ((flags & RFPROC) == 0)
return (EINVAL);
/* Must provide a place to put a procdesc if creating one. */
if (procdescp == NULL)
return (EINVAL);
}
#endif
p1 = td->td_proc;
/*
@ -757,6 +814,25 @@ fork1(struct thread *td, int flags, int pages, struct proc **procp)
return (EAGAIN);
#endif
#ifdef PROCDESC
/*
* If required, create a process descriptor in the parent first; we
* will abandon it if something goes wrong. We don't finit() until
* later.
*/
if (flags & RFPROCDESC) {
error = falloc(td, &fp_procdesc, procdescp, 0);
if (error != 0) {
#ifdef RACCT
PROC_LOCK(p1);
racct_sub(p1, RACCT_NPROC, 1);
PROC_UNLOCK(p1);
#endif
return (error);
}
}
#endif
mem_charged = 0;
vm2 = NULL;
if (pages == 0)
@ -868,12 +944,16 @@ fork1(struct thread *td, int flags, int pages, struct proc **procp)
PROC_UNLOCK(p1);
}
if (ok) {
do_fork(td, flags, newproc, td2, vm2);
do_fork(td, flags, newproc, td2, vm2, pdflags);
/*
* Return child proc pointer to parent.
*/
*procp = newproc;
#ifdef PROCDESC
if (flags & RFPROCDESC)
procdesc_finit(newproc->p_procdesc, fp_procdesc);
#endif
return (0);
}
@ -892,6 +972,10 @@ fork1(struct thread *td, int flags, int pages, struct proc **procp)
if (vm2 != NULL)
vmspace_free(vm2);
uma_zfree(proc_zone, newproc);
#ifdef PROCDESC
if (((flags & RFPROCDESC) != 0) && (fp_procdesc != NULL))
fdrop(fp_procdesc, td);
#endif
pause("fork", hz / 2);
#ifdef RACCT
PROC_LOCK(p1);

2
sys/kern/kern_kthread.c
View File

@ -88,7 +88,7 @@ kproc_create(void (*func)(void *), void *arg,
panic("kproc_create called too soon");
error = fork1(&thread0, RFMEM | RFFDG | RFPROC | RFSTOPPED | flags,
pages, &p2);
pages, &p2, NULL, 0);
if (error)
return error;

31
sys/kern/kern_sig.c
View File

@ -41,12 +41,14 @@ __FBSDID("$FreeBSD$");
#include "opt_kdtrace.h"
#include "opt_ktrace.h"
#include "opt_core.h"
#include "opt_procdesc.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/signalvar.h>
#include <sys/vnode.h>
#include <sys/acct.h>
#include <sys/capability.h>
#include <sys/condvar.h>
#include <sys/event.h>
#include <sys/fcntl.h>
@ -59,6 +61,7 @@ __FBSDID("$FreeBSD$");
#include <sys/mutex.h>
#include <sys/namei.h>
#include <sys/proc.h>
#include <sys/procdesc.h>
#include <sys/posix4.h>
#include <sys/pioctl.h>
#include <sys/racct.h>
@ -1698,6 +1701,34 @@ kill(struct thread *td, struct kill_args *uap)
/* NOTREACHED */
}
int
pdkill(td, uap)
struct thread *td;
struct pdkill_args *uap;
{
#ifdef PROCDESC
struct proc *p;
int error;
AUDIT_ARG_SIGNUM(uap->signum);
AUDIT_ARG_FD(uap->fd);
if ((u_int)uap->signum > _SIG_MAXSIG)
return (EINVAL);
error = procdesc_find(td, uap->fd, CAP_PDKILL, &p);
if (error)
return (error);
AUDIT_ARG_PROCESS(p);
error = p_cansignal(td, p, uap->signum);
if (error == 0 && uap->signum)
psignal(p, uap->signum);
PROC_UNLOCK(p);
return (error);
#else
return (ENOSYS);
#endif
}
#if defined(COMPAT_43)
#ifndef _SYS_SYSPROTO_H_
struct okillpg_args {

524
sys/kern/sys_procdesc.c Normal file
View File

@ -0,0 +1,524 @@
/*-
* Copyright (c) 2009 Robert N. M. Watson
* All rights reserved.
*
* This software was developed at the University of Cambridge Computer
* Laboratory with support from a grant from Google, 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.
*
* 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 process descriptor facility.
*
* Some processes are represented by a file descriptor, which will be used in
* preference to signaling and pids for the purposes of process management,
* and is, in effect, a form of capability. When a process descriptor is
* used with a process, it ceases to be visible to certain traditional UNIX
* process facilities, such as waitpid(2).
*
* Some semantics:
*
* - At most one process descriptor will exist for any process, although
* references to that descriptor may be held from many processes (or even
* be in flight between processes over a local domain socket).
* - Last close on the process descriptor will terminate the process using
* SIGKILL and reparent it to init so that there's a process to reap it
* when it's done exiting.
* - If the process exits before the descriptor is closed, it will not
* generate SIGCHLD on termination, or be picked up by waitpid().
* - The pdkill(2) system call may be used to deliver a signal to the process
* using its process descriptor.
* - The pdwait4(2) system call may be used to block (or not) on a process
* descriptor to collect termination information.
*
* Open questions:
*
* - How to handle ptrace(2)?
* - Will we want to add a pidtoprocdesc(2) system call to allow process
* descriptors to be created for processes without pfork(2)?
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_procdesc.h"
#include <sys/param.h>
#include <sys/capability.h>
#include <sys/fcntl.h>
#include <sys/file.h>
#include <sys/filedesc.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/poll.h>
#include <sys/proc.h>
#include <sys/procdesc.h>
#include <sys/resourcevar.h>
#include <sys/stat.h>
#include <sys/sysproto.h>
#include <sys/sysctl.h>
#include <sys/systm.h>
#include <sys/ucred.h>
#include <security/audit/audit.h>
#include <vm/uma.h>
#ifdef PROCDESC
FEATURE(process_descriptors, "Process Descriptors");
static uma_zone_t procdesc_zone;
static fo_rdwr_t procdesc_read;
static fo_rdwr_t procdesc_write;
static fo_truncate_t procdesc_truncate;
static fo_ioctl_t procdesc_ioctl;
static fo_poll_t procdesc_poll;
static fo_kqfilter_t procdesc_kqfilter;
static fo_stat_t procdesc_stat;
static fo_close_t procdesc_close;
static fo_chmod_t procdesc_chmod;
static fo_chown_t procdesc_chown;
static struct fileops procdesc_ops = {
.fo_read = procdesc_read,
.fo_write = procdesc_write,
.fo_truncate = procdesc_truncate,
.fo_ioctl = procdesc_ioctl,
.fo_poll = procdesc_poll,
.fo_kqfilter = procdesc_kqfilter,
.fo_stat = procdesc_stat,
.fo_close = procdesc_close,
.fo_chmod = procdesc_chmod,
.fo_chown = procdesc_chown,
.fo_flags = DFLAG_PASSABLE,
};
/*
* Initialize with VFS so that process descriptors are available along with
* other file descriptor types. As long as it runs before init(8) starts,
* there shouldn't be a problem.
*/
static void
procdesc_init(void *dummy __unused)
{
procdesc_zone = uma_zcreate("procdesc", sizeof(struct procdesc),
NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
if (procdesc_zone == NULL)
panic("procdesc_init: procdesc_zone not initialized");
}
SYSINIT(vfs, SI_SUB_VFS, SI_ORDER_ANY, procdesc_init, NULL);
/*
* Return a locked process given a process descriptor, or ESRCH if it has
* died.
*/
int
procdesc_find(struct thread *td, int fd, cap_rights_t rights,
struct proc **p)
{
struct procdesc *pd;
struct file *fp;
int error;
error = fget(td, fd, rights, &fp);
if (error)
return (error);
if (fp->f_type != DTYPE_PROCDESC) {
error = EBADF;
goto out;
}
pd = fp->f_data;
sx_slock(&proctree_lock);
if (pd->pd_proc != NULL) {
*p = pd->pd_proc;
PROC_LOCK(*p);
} else
error = ESRCH;
sx_sunlock(&proctree_lock);
out:
fdrop(fp, td);
return (error);
}
/*
* Function to be used by procstat(1) sysctls when returning procdesc
* information.
*/
pid_t
procdesc_pid(struct file *fp_procdesc)
{
struct procdesc *pd;
KASSERT(fp_procdesc->f_type == DTYPE_PROCDESC,
("procdesc_pid: !procdesc"));
pd = fp_procdesc->f_data;
return (pd->pd_pid);
}
/*
* Retrieve the PID associated with a process descriptor.
*/
int
kern_pdgetpid(struct thread *td, int fd, cap_rights_t rights, pid_t *pidp)
{
struct file *fp;
int error;
error = fget(td, fd, rights, &fp);
if (error)
return (error);
if (fp->f_type != DTYPE_PROCDESC) {
error = EBADF;
goto out;
}
*pidp = procdesc_pid(fp);
out:
fdrop(fp, td);
return (error);
}
/*
* System call to return the pid of a process given its process descriptor.
*/
int
pdgetpid(struct thread *td, struct pdgetpid_args *uap)
{
pid_t pid;
int error;
AUDIT_ARG_FD(uap->fd);
error = kern_pdgetpid(td, uap->fd, CAP_PDGETPID, &pid);
if (error == 0)
error = copyout(&pid, uap->pidp, sizeof(pid));
return (error);
}
/*
* When a new process is forked by pdfork(), a file descriptor is allocated
* by the fork code first, then the process is forked, and then we get a
* chance to set up the process descriptor. Failure is not permitted at this
* point, so procdesc_new() must succeed.
*/
void
procdesc_new(struct proc *p, int flags)
{
struct procdesc *pd;
pd = uma_zalloc(procdesc_zone, M_WAITOK | M_ZERO);
pd->pd_proc = p;
pd->pd_pid = p->p_pid;
p->p_procdesc = pd;
pd->pd_flags = 0;
if (flags & PD_DAEMON)
pd->pd_flags |= PDF_DAEMON;
PROCDESC_LOCK_INIT(pd);
/*
* Process descriptors start out with two references: one from their
* struct file, and the other from their struct proc.
*/
refcount_init(&pd->pd_refcount, 2);
}
/*
* Initialize a file with a process descriptor.
*/
void
procdesc_finit(struct procdesc *pdp, struct file *fp)
{
finit(fp, FREAD | FWRITE, DTYPE_PROCDESC, pdp, &procdesc_ops);
}
static void
procdesc_free(struct procdesc *pd)
{
/*
* When the last reference is released, we assert that the descriptor
* has been closed, but not that the process has exited, as we will
* detach the descriptor before the process dies if the descript is
* closed, as we can't wait synchronously.
*/
if (refcount_release(&pd->pd_refcount)) {
KASSERT(pd->pd_proc == NULL,
("procdesc_free: pd_proc != NULL"));
KASSERT((pd->pd_flags & PDF_CLOSED),
("procdesc_free: !PDF_CLOSED"));
PROCDESC_LOCK_DESTROY(pd);
uma_zfree(procdesc_zone, pd);
}
}
/*
* procdesc_exit() - notify a process descriptor that its process is exiting.
* We use the proctree_lock to ensure that process exit either happens
* strictly before or strictly after a concurrent call to procdesc_close().
*/
int
procdesc_exit(struct proc *p)
{
struct procdesc *pd;
sx_assert(&proctree_lock, SA_XLOCKED);
PROC_LOCK_ASSERT(p, MA_OWNED);
KASSERT(p->p_procdesc != NULL, ("procdesc_exit: p_procdesc NULL"));
pd = p->p_procdesc;
PROCDESC_LOCK(pd);
KASSERT((pd->pd_flags & PDF_CLOSED) == 0 || p->p_pptr == initproc,
("procdesc_exit: closed && parent not init"));
pd->pd_flags |= PDF_EXITED;
/*
* If the process descriptor has been closed, then we have nothing
* to do; return 1 so that init will get SIGCHLD and do the reaping.
* Clean up the procdesc now rather than letting it happen during
* that reap.
*/
if (pd->pd_flags & PDF_CLOSED) {
PROCDESC_UNLOCK(pd);
pd->pd_proc = NULL;
p->p_procdesc = NULL;
procdesc_free(pd);
return (1);
}
if (pd->pd_flags & PDF_SELECTED) {
pd->pd_flags &= ~PDF_SELECTED;
selwakeup(&pd->pd_selinfo);
}
PROCDESC_UNLOCK(pd);
return (0);
}
/*
* When a process descriptor is reaped, perhaps as a result of close() or
* pdwait4(), release the process's reference on the process descriptor.
*/
void
procdesc_reap(struct proc *p)
{
struct procdesc *pd;
sx_assert(&proctree_lock, SA_XLOCKED);
KASSERT(p->p_procdesc != NULL, ("procdesc_reap: p_procdesc == NULL"));
pd = p->p_procdesc;
pd->pd_proc = NULL;
procdesc_free(pd);
}
/*
* procdesc_close() - last close on a process descriptor. If the process is
* still running, terminate with SIGKILL (unless PD_DAEMON is set) and let
* init(8) clean up the mess; if not, we have to clean up the zombie ourselves.
*/
static int
procdesc_close(struct file *fp, struct thread *td)
{
struct procdesc *pd;
struct proc *p;
KASSERT(fp->f_type == DTYPE_PROCDESC, ("procdesc_close: !procdesc"));
pd = fp->f_data;
fp->f_ops = &badfileops;
fp->f_data = NULL;
sx_xlock(&proctree_lock);
PROCDESC_LOCK(pd);
pd->pd_flags |= PDF_CLOSED;
PROCDESC_UNLOCK(pd);
p = pd->pd_proc;
PROC_LOCK(p);
if (p->p_state == PRS_ZOMBIE) {
/*
* If the process is already dead and just awaiting reaping,
* do that now. This will release the process's reference to
* the process descriptor when it calls back into
* procdesc_reap().
*/
PROC_SLOCK(p);
proc_reap(curthread, p, NULL, 0, NULL);
} else {
/*
* If the process is not yet dead, we need to kill it, but we
* can't wait around synchronously for it to go away, as that
* path leads to madness (and deadlocks). First, detach the
* process from its descriptor so that its exit status will
* be reported normally.
*/
pd->pd_proc = NULL;
p->p_procdesc = NULL;
procdesc_free(pd);
/*
* Next, reparent it to init(8) so that there's someone to
* pick up the pieces; finally, terminate with prejudice.
*/
p->p_sigparent = SIGCHLD;
proc_reparent(p, initproc);
if ((pd->pd_flags & PD_DAEMON) == 0)
psignal(p, SIGKILL);
PROC_UNLOCK(p);
sx_xunlock(&proctree_lock);
}
/*
* Release the file descriptor's reference on the process descriptor.
*/
procdesc_free(pd);
return (0);
}
static int
procdesc_read(struct file *fp, struct uio *uio, struct ucred *active_cred,
int flags, struct thread *td)
{
return (EOPNOTSUPP);
}
static int
procdesc_write(struct file *fp, struct uio *uio, struct ucred *active_cred,
int flags, struct thread *td)
{
return (EOPNOTSUPP);
}
static int
procdesc_truncate(struct file *fp, off_t length, struct ucred *active_cred,
struct thread *td)
{
return (EOPNOTSUPP);
}
static int
procdesc_ioctl(struct file *fp, u_long com, void *data,
struct ucred *active_cred, struct thread *td)
{
return (EOPNOTSUPP);
}
static int
procdesc_poll(struct file *fp, int events, struct ucred *active_cred,
struct thread *td)
{
struct procdesc *pd;
int revents;
revents = 0;
pd = fp->f_data;
PROCDESC_LOCK(pd);
if (pd->pd_flags & PDF_EXITED)
revents |= POLLHUP;
if (revents == 0) {
selrecord(td, &pd->pd_selinfo);
pd->pd_flags |= PDF_SELECTED;
}
PROCDESC_UNLOCK(pd);
return (revents);
}
static int
procdesc_kqfilter(struct file *fp, struct knote *kn)
{
return (EOPNOTSUPP);
}
static int
procdesc_stat(struct file *fp, struct stat *sb, struct ucred *active_cred,
struct thread *td)
{
struct procdesc *pd;
struct timeval pstart;
/*
* XXXRW: Perhaps we should cache some more information from the
* process so that we can return it reliably here even after it has
* died. For example, caching its credential data.
*/
bzero(sb, sizeof(*sb));
pd = fp->f_data;
sx_slock(&proctree_lock);
if (pd->pd_proc != NULL) {
PROC_LOCK(pd->pd_proc);
/* Set birth and [acm] times to process start time. */
pstart = pd->pd_proc->p_stats->p_start;
timevaladd(&pstart, &boottime);
TIMEVAL_TO_TIMESPEC(&pstart, &sb->st_birthtim);
sb->st_atim = sb->st_birthtim;
sb->st_ctim = sb->st_birthtim;
sb->st_mtim = sb->st_birthtim;
if (pd->pd_proc->p_state != PRS_ZOMBIE)
sb->st_mode = S_IFREG | S_IRWXU;
else
sb->st_mode = S_IFREG;
sb->st_uid = pd->pd_proc->p_ucred->cr_ruid;
sb->st_gid = pd->pd_proc->p_ucred->cr_rgid;
PROC_UNLOCK(pd->pd_proc);
} else
sb->st_mode = S_IFREG;
sx_sunlock(&proctree_lock);
return (0);
}
static int
procdesc_chmod(struct file *fp, mode_t mode, struct ucred *active_cred,
struct thread *td)
{
return (EOPNOTSUPP);
}
static int
procdesc_chown(struct file *fp, uid_t uid, gid_t gid, struct ucred *active_cred,
struct thread *td)
{
return (EOPNOTSUPP);
}
#else /* !PROCDESC */
int
pdgetpid(struct thread *td, struct pdgetpid_args *uap)
{
return (ENOSYS);
}
#endif /* PROCDESC */

8
sys/kern/syscalls.master
View File

@ -919,10 +919,10 @@
u_int64_t *rightsp); }
516 AUE_CAP_ENTER STD { int cap_enter(void); }
517 AUE_CAP_GETMODE STD { int cap_getmode(u_int *modep); }
518 AUE_PDFORK UNIMPL pdfork
519 AUE_PDKILL UNIMPL pdkill
520 AUE_PDGETPID UNIMPL pdgetpid
521 AUE_PDWAIT UNIMPL pdwait
518 AUE_PDFORK STD { int pdfork(int *fdp, int flags); }
519 AUE_PDKILL STD { int pdkill(int fd, int signum); }
520 AUE_PDGETPID STD { int pdgetpid(int fd, pid_t *pidp); }
521 AUE_PDWAIT UNIMPL pdwait4
522 AUE_SELECT STD { int pselect(int nd, fd_set *in, \
fd_set *ou, fd_set *ex, \
const struct timespec *ts, \

7
sys/sys/capability.h
View File

@ -131,8 +131,13 @@
#define CAP_IOCTL 0x0004000000000000ULL
#define CAP_TTYHOOK 0x0008000000000000ULL
/* Process management via process descriptors. */
#define CAP_PDGETPID 0x0010000000000000ULL
#define CAP_PDWAIT 0x0020000000000000ULL
#define CAP_PDKILL 0x0040000000000000ULL
/* The mask of all valid method rights. */
#define CAP_MASK_VALID 0x000fffffffffffffULL
#define CAP_MASK_VALID 0x007fffffffffffffULL
#ifdef _KERNEL

1
sys/sys/file.h
View File

@ -65,6 +65,7 @@ struct socket;
#define DTYPE_PTS 10 /* pseudo teletype master device */
#define DTYPE_DEV 11 /* Device specific fd type */
#define DTYPE_CAPABILITY 12 /* capability */
#define DTYPE_PROCDESC 13 /* process descriptor */
#ifdef _KERNEL

6
sys/sys/proc.h
View File

@ -166,6 +166,7 @@ struct mqueue_notifier;
struct nlminfo;
struct p_sched;
struct proc;
struct procdesc;
struct racct;
struct sleepqueue;
struct td_sched;
@ -534,6 +535,7 @@ struct proc {
int p_boundary_count;/* (c) Num threads at user boundary */
int p_pendingcnt; /* how many signals are pending */
struct itimers *p_itimers; /* (c) POSIX interval timers. */
struct procdesc *p_procdesc; /* (e) Process descriptor, if any. */
/* End area that is zeroed on creation. */
#define p_endzero p_magic
@ -822,7 +824,7 @@ int enterpgrp(struct proc *p, pid_t pgid, struct pgrp *pgrp,
int enterthispgrp(struct proc *p, struct pgrp *pgrp);
void faultin(struct proc *p);
void fixjobc(struct proc *p, struct pgrp *pgrp, int entering);
int fork1(struct thread *, int, int, struct proc **);
int fork1(struct thread *, int, int, struct proc **, int *, int);
void fork_exit(void (*)(void *, struct trapframe *), void *,
struct trapframe *);
void fork_return(struct thread *, struct trapframe *);
@ -844,6 +846,8 @@ void pargs_hold(struct pargs *pa);
void procinit(void);
void proc_linkup0(struct proc *p, struct thread *td);
void proc_linkup(struct proc *p, struct thread *td);
void proc_reap(struct thread *td, struct proc *p, int *status, int options,
struct rusage *rusage);
void proc_reparent(struct proc *child, struct proc *newparent);
struct pstats *pstats_alloc(void);
void pstats_fork(struct pstats *src, struct pstats *dst);

119
sys/sys/procdesc.h Normal file
View File

@ -0,0 +1,119 @@
/*-
* Copyright (c) 2009 Robert N. M. Watson
* All rights reserved.
*
* This software was developed at the University of Cambridge Computer
* Laboratory with support from a grant from Google, 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.
*
* 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_PROCDESC_H_
#define _SYS_PROCDESC_H_
#ifdef _KERNEL
#include <sys/selinfo.h> /* struct selinfo */
#include <sys/_lock.h>
#include <sys/_mutex.h>
/*-
* struct procdesc describes a process descriptor, and essentially consists
* of two pointers -- one to the file descriptor, and one to the process.
* When both become NULL, the process descriptor will be freed. An important
* invariant is that there is only ever one process descriptor for a process,
* so a single file pointer will suffice.
*
* Locking key:
* (c) - Constant after initial setup.
* (p) - Protected by the process descriptor mutex.
* (r) - Atomic eference count.
* (s) - Protected by selinfo.
* (t) - Protected by the proctree_lock
*/
struct proc;
struct sigio;
struct procdesc {
/*
* Basic process descriptor state: the process, a cache of its pid to
* satisfy queries after the process exits, and process descriptor
* refcount.
*/
struct proc *pd_proc; /* (t) Process. */
pid_t pd_pid; /* (c) Cached pid. */
u_int pd_refcount; /* (r) Reference count. */
/*
* In-flight data and notification of events.
*/
int pd_flags; /* (p) PD_ flags. */
struct selinfo pd_selinfo; /* (p) Event notification. */
struct mtx pd_lock; /* Protect data + events. */
};
/*
* Locking macros for the procdesc itself.
*/
#define PROCDESC_LOCK_DESTROY(pd) mtx_destroy(&(pd)->pd_lock)
#define PROCDESC_LOCK_INIT(pd) mtx_init(&(pd)->pd_lock, "procdesc", NULL, \
MTX_DEF)
#define PROCDESC_LOCK(pd) mtx_lock(&(pd)->pd_lock)
#define PROCDESC_UNLOCK(pd) mtx_unlock(&(pd)->pd_lock)
/*
* Flags for the pd_flags field.
*/
#define PDF_CLOSED 0x00000001 /* Descriptor has closed. */
#define PDF_SELECTED 0x00000002 /* Issue selwakeup(). */
#define PDF_EXITED 0x00000004 /* Process exited. */
#define PDF_DAEMON 0x00000008 /* Don't exit when procdesc closes. */
/*
* In-kernel interfaces to process descriptors.
*/
int procdesc_exit(struct proc *);
int procdesc_find(struct thread *, int fd, cap_rights_t, struct proc **);
int kern_pdgetpid(struct thread *, int fd, cap_rights_t, pid_t *pidp);
void procdesc_new(struct proc *, int);
void procdesc_finit(struct procdesc *, struct file *);
pid_t procdesc_pid(struct file *);
void procdesc_reap(struct proc *);
#else /* !_KERNEL */
/*
* Process descriptor system calls.
*/
struct rusage;
int pdfork(int *, int);
int pdkill(int, int);
int pdgetpid(int, pid_t *);
#endif /* _KERNEL */
/*
* Flags which can be passed to pdfork(2).
*/
#define PD_DAEMON 0x00000001 /* Don't exit when procdesc closes. */
#endif /* !_SYS_PROCDESC_H_ */

5
sys/sys/unistd.h
View File

@ -185,11 +185,12 @@
#define RFTSIGMASK 0xFF
#define RFTSIGNUM(flags) (((flags) >> RFTSIGSHIFT) & RFTSIGMASK)
#define RFTSIGFLAGS(signum) ((signum) << RFTSIGSHIFT)
#define RFPROCDESC (1<<28) /* return a process descriptor */
#define RFPPWAIT (1<<31) /* parent sleeps until child exits (vfork) */
#define RFKERNELONLY (RFSTOPPED | RFHIGHPID | RFPPWAIT)
#define RFFLAGS (RFFDG | RFPROC | RFMEM | RFNOWAIT | RFCFDG | \
RFTHREAD | RFSIGSHARE | RFLINUXTHPN | RFSTOPPED | RFHIGHPID | RFTSIGZMB | \
RFPPWAIT)
RFPROCDESC | RFPPWAIT)
#define RFKERNELONLY (RFSTOPPED | RFHIGHPID | RFPPWAIT | RFPROCDESC)
#endif /* __BSD_VISIBLE */

4
sys/sys/user.h
View File

@ -252,6 +252,7 @@ struct user {
#define KF_TYPE_SEM 9
#define KF_TYPE_PTS 10
/* no KF_TYPE_CAPABILITY (11), since capabilities wrap other file objects */
#define KF_TYPE_PROCDESC 12
#define KF_TYPE_UNKNOWN 255
#define KF_VTYPE_VNON 0
@ -377,6 +378,9 @@ struct kinfo_file {
/* Round to 64 bit alignment. */
uint32_t kf_pts_pad0[7];
} kf_pts;
struct {
pid_t kf_pid;
} kf_proc;
} kf_un;
uint16_t kf_status; /* Status flags. */
uint16_t kf_pad1; /* Round to 32 bit alignment. */