freebsd-dev/lib/libutil/getlocalbase.3
Jessica Clarke 3a46fe2261 getlocalbase: Make default path actually configurable
We include paths.h in getlocalbase.c, which defines _PATH_LOCALBASE.
This will override a definition on the command line, meaning it is
impossible to override like how the manpage says you can, and it means
the code to provide a fallback default is dead as the macro is always
defined.

Instead, introduce a new LOCALBASE_PATH macro like LOCALBASE_CTL_LEN
that can be set on the command line and will default to the system's
existing _PATH_LOCALBASE to avoid duplicating the default here.

Reviewed by:	imp
Differential Revision:	https://reviews.freebsd.org/D40975
2023-07-11 21:49:22 +01:00

124 lines
3.8 KiB
Groff

.\"
.\" SPDX-License-Identifier: BSD-2-Clause
.\"
.\" Copyright 2020 Scott Long
.\" Copyright 2020 Stefan Eßer
.\"
.\" 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 AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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 July 11, 2023
.Dt GETLOCALBASE 3
.Os
.Sh NAME
.Nm getlocalbase
.Nd "return the path to the local software directory"
.Sh LIBRARY
.Lb libutil
.Sh SYNOPSIS
.In libutil.h
.Ft const char*
.Fn getlocalbase "void"
.Sh DESCRIPTION
The
.Fn getlocalbase
function returns the path to the local software base directory.
Normally this is the
.Pa /usr/local
directory.
First the
.Ev LOCALBASE
environment variable is checked.
If that does not exist then the
.Va user.localbase
sysctl is checked.
If that also does not exist then the value of the
.Dv LOCALBASE_PATH
compile-time variable is used.
If that is undefined then the system default,
.Pa _PATH_LOCALBASE
is used.
.Pp
The contents of the string returned by the
.Fn getlocalbase
function shall not be modified.
.Sh IMPLEMENTATION NOTES
Calls to
.Fn getlocalbase
will perform a setugid check on the running binary before checking the
environment.
.Pp
The address returned by
.Fn getlocalbase
will point into the executing processes environment if it is the result of
.Fn getenv "LOCALBASE" ,
to a static buffer if it is the result of
.Fn sysctl "user.localbase" ,
and to a constant string if the compiled in default value is returned.
.Pp
The same value will be returned on successive calls during the run-time
of the program, ignoring any changes to the environment variable or the
sysctl value that might have been made.
.Pp
The
.Fn getlocalbase
function can be compiled with a non-default value of LOCALBASE_CTL_LEN.
A value of 0 will disable fetching of the sysctl value, a value less than
MAXPATHLEN will put a limit on the maximum string length supported for
this sysctl value.
If built with a non-default value of LOCALBASE_CTL_LEN, a value of the
user.localbase sysctl variable longer than this value will make
.Fn getlocalbase
return a valid string that is not a valid path prefix in any filesystem.
.Sh RETURN VALUES
The
.Fn getlocalbase
function returns a pointer to a string, whose length may exceed MAXPATHLEN,
if it has been obtained from the environment.
.Sh ENVIRONMENT
The
.Fn getlocalbase
library function retrieves the
.Ev LOCALBASE
environment variable.
.Sh ERRORS
The
.Fn getlocalbase
function always succeeds and returns a valid pointer to a string.
.Sh SEE ALSO
.Xr env 1 ,
.Xr src.conf 5 ,
.Xr sysctl 8
.Sh HISTORY
The
.Nm
library function first appeared in
.Fx 13.0 .
.Sh AUTHORS
.An -nosplit
This
manual page was written by
.An Scott Long Aq Mt scottl@FreeBSD.org
and
.An Stefan Eßer Aq Mt se@FreeBSD.org .