xref: /freebsd/lib/libutil/kinfo_getvmmap.3 (revision a03411e84728e9b267056fd31c7d1d9d1dc1b01e)
1.\"
2.\" Copyright (c) 2008 Peter Wemm
3.\" All rights reserved.
4.\"
5.\" Redistribution and use in source and binary forms, with or without
6.\" modification, are permitted provided that the following conditions
7.\" are met:
8.\" 1. Redistributions of source code must retain the above copyright
9.\"    notice, this list of conditions and the following disclaimer.
10.\" 2. Redistributions in binary form must reproduce the above copyright
11.\"    notice, this list of conditions and the following disclaimer in the
12.\"    documentation and/or other materials provided with the distribution.
13.\"
14.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24.\" SUCH DAMAGE.
25.\"
26.Dd May 10, 2020
27.Dt KINFO_GETVMMAP 3
28.Os
29.Sh NAME
30.Nm kinfo_getvmmap
31.Nd function for getting per-process memory map information
32.Sh LIBRARY
33.Lb libutil
34.Sh SYNOPSIS
35.In sys/types.h
36.In sys/user.h
37.In libutil.h
38.Ft struct kinfo_vmentry *
39.Fn kinfo_getvmmap "pid_t pid" "int *cntp"
40.Sh DESCRIPTION
41This function is used for obtaining virtual memory mapping information
42of a particular process.
43.Pp
44The
45.Ar pid
46field contains the process identifier.
47This should be the a process that you have privilege to access.
48The
49.Ar cntp
50field is allows the caller to know how many records are returned.
51.Pp
52This function is a wrapper around
53.Xr sysctl 3
54with the
55.Dv KERN_PROC_VMMAP
56mib.
57While the kernel returns a packed structure, this function expands the
58data into a fixed record format.
59.Sh RETURN VALUES
60On success the
61.Fn kinfo_getvmmap
62function returns a pointer to an array of
63.Vt struct kinfo_vmentry
64structures as defined by
65.In sys/user.h .
66The array was obtained by an internal call to
67.Xr malloc 3
68and must be freed by the caller with a call to
69.Xr free 3 .
70On failure the
71.Fn kinfo_getvmmap
72function returns
73.Dv NULL .
74.Sh SEE ALSO
75.Xr free 3 ,
76.Xr kinfo_getfile 3 ,
77.Xr malloc 3
78.Sh HISTORY
79The
80.Fn kinfo_getvmmap
81function first appeared in
82.Fx 7.0 .
83.Sh CAVEATS
84.Fn kinfo_getvmmap
85calls can cause significant CPU consumption because calculating the residency
86counts requires iterating over all memory pages of the process.
87Setting the sysctl variable
88.Va kern.proc_vmmap_skip_resident_count
89to 1 prevents this calculation.
90