240 lines
6.5 KiB
Groff
240 lines
6.5 KiB
Groff
.\" $NetBSD: kvm_getprocs.3,v 1.17 2018/01/09 21:17:45 kamil Exp $
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.\"
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.\" Copyright (c) 1992, 1993
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.\" The Regents of the University of California. All rights reserved.
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.\"
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.\" This code is derived from software developed by the Computer Systems
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.\" Engineering group at Lawrence Berkeley Laboratory under DARPA contract
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.\" BG 91-66 and contributed to Berkeley.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" @(#)kvm_getprocs.3 8.1 (Berkeley) 6/4/93
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.\"
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.Dd January 9, 2018
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.Dt KVM_GETPROCS 3
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.Os
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.Sh NAME
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.Nm kvm_getprocs ,
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.Nm kvm_getargv ,
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.Nm kvm_getenvv ,
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.Nm kvm_getproc2 ,
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.Nm kvm_getargv2 ,
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.Nm kvm_getenvv2
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.Nd access user process state
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.Sh LIBRARY
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.Lb libkvm
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.Sh SYNOPSIS
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.In kvm.h
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.In sys/param.h
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.In sys/sysctl.h
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.\" .Fa kvm_t *kd
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.Ft struct kinfo_proc *
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.Fn kvm_getprocs "kvm_t *kd" "int op" "int arg" "int *cnt"
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.Ft char **
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.Fn kvm_getargv "kvm_t *kd" "const struct kinfo_proc *p" "int nchr"
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.Ft char **
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.Fn kvm_getenvv "kvm_t *kd" "const struct kinfo_proc *p" "int nchr"
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.Ft struct kinfo_proc2 *
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.Fn kvm_getproc2 "kvm_t *kd" "int op" "int arg" "size_t elemsize" "int *cnt"
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.Ft char **
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.Fn kvm_getargv2 "kvm_t *kd" "const struct kinfo_proc2 *p" "int nchr"
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.Ft char **
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.Fn kvm_getenvv2 "kvm_t *kd" "const struct kinfo_proc2 *p" "int nchr"
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.Sh DESCRIPTION
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.Fn kvm_getprocs
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returns a (sub-)set of active processes in the kernel indicated by
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.Fa kd .
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The
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.Fa op
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and
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.Fa arg
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arguments constitute a predicate
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which limits the set of processes returned.
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The value of
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.Fa op
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describes the filtering predicate as follows:
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.Pp
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.Bl -tag -width 20n -offset indent -compact
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.It Sy KERN_PROC_ALL
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all processes
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.It Sy KERN_PROC_PID
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processes with process id
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.Fa arg
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.It Sy KERN_PROC_PGRP
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processes with process group
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.Fa arg
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.It Sy KERN_PROC_SESSION
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processes with session id
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.Fa arg
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.It Sy KERN_PROC_TTY
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processes with tty device
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.Fa arg
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.It Sy KERN_PROC_UID
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processes with effective user id
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.Fa arg
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.It Sy KERN_PROC_RUID
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processes with real user id
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.Fa arg
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.It Sy KERN_PROC_GID
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processes with effective group id
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.Fa arg
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.It Sy KERN_PROC_RGID
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processes with real group id
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.Fa arg
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.El
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.Pp
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The number of processes found is returned in the reference parameter
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.Fa cnt .
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The processes are returned as a contiguous array of
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.Sy kinfo_proc
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structures.
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This memory is locally allocated, and subsequent calls to
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.Fn kvm_getprocs
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and
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.Fn kvm_close
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will overwrite this storage.
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.Pp
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If the
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.Fa op
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argument for
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.Fn kvm_getprocs
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is
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.Sy KERN_PROC_TTY ,
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.Fa arg
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can also be
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.Sy KERN_PROC_TTY_NODEV
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to select processes with no controlling tty and
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.Sy KERN_PROC_TTY_REVOKE
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to select processes which have had their controlling tty
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revoked.
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.Pp
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.Fn kvm_getargv
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returns a null-terminated argument vector that corresponds to the
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command line arguments passed to process indicated by
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.Fa p .
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Most likely, these arguments correspond to the values passed to
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.Xr exec 3
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on process creation.
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This information is, however,
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deliberately under control of the process itself.
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Note that the original command name can be found, unaltered,
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in the p_comm field of the process structure returned by
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.Fn kvm_getprocs .
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.Pp
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The
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.Fa nchr
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argument indicates the maximum number of characters, including null bytes,
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to use in building the strings.
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If this amount is exceeded, the string
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causing the overflow is truncated and the partial result is returned.
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This is handy for programs like
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.Xr ps 1
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and
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.Xr w 1
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that print only a one line summary of a command and should not copy
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out large amounts of text only to ignore it.
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If
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.Fa nchr
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is zero, no limit is imposed and all argument strings are returned in
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their entirety.
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.Pp
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The memory allocated to the argv pointers and string storage
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is owned by the kvm library.
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Subsequent
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.Fn kvm_getprocs
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and
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.Xr kvm_close 3
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calls will clobber this storage.
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.Pp
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The
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.Fn kvm_getenvv
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function is similar to
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.Fn kvm_getargv
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but returns the vector of environment strings.
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This data is also alterable by the process.
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.Pp
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.Fn kvm_getproc2
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is similar to
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.Fn kvm_getprocs
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but returns an array of
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.Sy kinfo_proc2
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structures.
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Additionally, only the first
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.Fa elemsize
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bytes of each array entry are returned.
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If the size of the
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.Sy kinfo_proc2
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structure increases in size in a future release of
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.Nx
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the kernel will only return the requested amount of data for
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each array entry and programs that use
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.Fn kvm_getproc2
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will continue to function without the need for recompilation.
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.Pp
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The
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.Fn kvm_getargv2
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and
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.Fn kvm_getenvv2
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are equivalents to the
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.Fn kvm_getargv
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and
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.Fn kvm_getenvv
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functions but use a
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.Sy kinfo_proc2
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structure to specify the process.
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.Pp
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If called against an active kernel, the
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.Fn kvm_getproc2 ,
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.Fn kvm_getargv2 ,
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and
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.Fn kvm_getenvv2
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functions will use the
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.Xr sysctl 3
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interface and do not require access to the kernel memory device
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file or swap device.
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.Sh RETURN VALUES
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.Fn kvm_getprocs ,
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.Fn kvm_getargv ,
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.Fn kvm_getenvv ,
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.Fn kvm_getproc2 ,
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.Fn kvm_getargv2 ,
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and
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.Fn kvm_getenvv2
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all return
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.Dv NULL
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on failure.
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.Sh SEE ALSO
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.Xr kvm 3 ,
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.Xr kvm_close 3 ,
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.Xr kvm_geterr 3 ,
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.Xr kvm_nlist 3 ,
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.Xr kvm_open 3 ,
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.Xr kvm_openfiles 3 ,
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.Xr kvm_read 3 ,
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.Xr kvm_write 3
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.Sh BUGS
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These routines do not belong in the kvm interface.
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