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Add a manpage for elf_aux_info(3)

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Differential Revision:	https://reviews.freebsd.org/D20063
This commit is contained in:
Ian Lepore 2019-04-26 15:43:14 +00:00
parent f841e638fb
commit 7d6386daa0
2 changed files with 88 additions and 0 deletions
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2
lib/libc/gen/Makefile.inc
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@ -193,6 +193,7 @@ SYM_MAPS+=${LIBC_SRCTOP}/gen/Symbol.map
MAN+= alarm.3 \
arc4random.3 \
auxv.3 \
basename.3 \
cap_rights_get.3 \
cap_sandboxed.3 \
@ -321,6 +322,7 @@ MAN+= alarm.3 \
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

86
lib/libc/gen/auxv.3 Normal file
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@ -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.