xref: /freebsd/lib/libutil/kinfo_getvmmap.3 (revision 5ffd83dbcc34f10e07f6d3e968ae6365869615f4)
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26.\" $FreeBSD$
27.\"
28.Dd May 10, 2020
29.Dt KINFO_GETVMMAP 3
30.Os
31.Sh NAME
32.Nm kinfo_getvmmap
33.Nd function for getting per-process memory map information
34.Sh LIBRARY
35.Lb libutil
36.Sh SYNOPSIS
37.In sys/types.h
38.In sys/user.h
39.In libutil.h
40.Ft struct kinfo_vmentry *
41.Fn kinfo_getvmmap "pid_t pid" "int *cntp"
42.Sh DESCRIPTION
43This function is used for obtaining virtual memory mapping information
44of a particular process.
45.Pp
46The
47.Ar pid
48field contains the process identifier.
49This should be the a process that you have privilege to access.
50The
51.Ar cntp
52field is allows the caller to know how many records are returned.
53.Pp
54This function is a wrapper around
55.Xr sysctl 3
56with the
57.Dv KERN_PROC_VMMAP
58mib.
59While the kernel returns a packed structure, this function expands the
60data into a fixed record format.
61.Sh CAVEAT
62.Fn kinfo_getvmmap
63calls can cause significant CPU consumption because calculating the residency
64counts requires iterating over all memory pages of the process.
65Setting the sysctl variable
66.Va kern.proc_vmmap_skip_resident_count
67to 1 prevents this calculation.
68.Sh RETURN VALUES
69On success the
70.Fn kinfo_getvmmap
71function returns a pointer to an array of
72.Vt struct kinfo_vmentry
73structures as defined by
74.In sys/user.h .
75The array was obtained by an internal call to
76.Xr malloc 3
77and must be freed by the caller with a call to
78.Xr free 3 .
79On failure the
80.Fn kinfo_getvmmap
81function returns
82.Dv NULL .
83.Sh SEE ALSO
84.Xr free 3 ,
85.Xr kinfo_getfile 3 ,
86.Xr malloc 3
87.Sh HISTORY
88The
89.Fn kinfo_getvmmap
90function first appeared in
91.Fx 7.0 .
92