Index: lib/libc/gen/Makefile.inc
===================================================================
--- lib/libc/gen/Makefile.inc
+++ lib/libc/gen/Makefile.inc
@@ -193,6 +193,7 @@
 
 MAN+=	alarm.3 \
 	arc4random.3 \
+	auxv.3 \
 	basename.3 \
 	cap_rights_get.3 \
 	cap_sandboxed.3 \
@@ -321,6 +322,7 @@
 
 MLINKS+=arc4random.3 arc4random_buf.3 \
 	arc4random.3 arc4random_uniform.3
+MLINKS+=auxv.3 elf_aux_info.3
 MLINKS+=ctermid.3 ctermid_r.3
 MLINKS+=devname.3 devname_r.3
 MLINKS+=devname.3 fdevname.3
Index: lib/libc/gen/auxv.3
===================================================================
--- lib/libc/gen/auxv.3
+++ lib/libc/gen/auxv.3
@@ -0,0 +1,86 @@
+.\"
+.\" Copyright (c) 2019 Ian Lepore <ian@freebsd.org>
+.\"
+.\" 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 ``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 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 April 25, 2019
+.Dt ELF_AUX_INFO 3
+.Os
+.Sh NAME
+.Nm elf_aux_info
+.Nd extract data from the elf auxiliary vector of the current process
+.Sh LIBRARY
+.Lb libc
+.Sh SYNOPSIS
+.In sys/auxv.h
+.Ft int
+.Fn elf_aux_info "int aux" "void *buf" "int buflen"
+.Sh DESCRIPTION
+The
+.Fn elf_aux_info
+function retrieves the auxiliary info vector requested in
+.Va aux .
+The information is stored into the provided buffer if it will fit.
+The following values, defined in
+.In sys/elf_common.h
+can be requested:
+.Bl -tag -width AT_OSRELDATE
+.It AT_CANARY
+The canary value for SSP.
+.It AT_HWCAP
+CPU / hardware feature flags.
+.It AT_HWCAP2
+CPU / hardware feature flags.
+.It AT_NCPUS
+Number of CPUs.
+.It AT_OSRELDATE
+Kernel OSRELDATE.
+.It AT_PAGESIZES
+Vector of page sizes.
+.It AT_PAGESZ
+Page size in bytes.
+.It AT_TIMEKEEP
+Pointer to VDSO timehands (for library internal use).
+.El
+.Sh RETURN VALUES
+Returns zero on success, or an error number on failure.
+.Sh ERRORS
+.Bl -tag -width Er
+.It Bq Er EINVAL
+An unknown item was requested.
+.It Bq Er EINVAL
+The provided buffer was not the right size for the requested item.
+.It Bq Er ENOENT
+The requested item is not available.
+.El
+.Sh HISTORY
+The
+.Fn elf_aux_info
+function appeared in
+.Fx 12.0 .
+.Sh BUGS
+Only a small subset of available auxiliary info vector items are
+accessible with this function.
+Some items require a "right-sized" buffer while others just require a
+"big enough" buffer.