freebsd-skq/lib/libutil/getlocalbase.c
Stefan Eßer 30d21d2795 Add function getlocalbase() to libutil.
This function returns the path to the local software base directory, by
default "/usr/local" (or the value of _PATH_LOCALBASE in include/paths.h
when building the world).

The value returned can be overridden by 2 methods:

- the LOCALBASE environment variable (ignored by SUID programs)
- else a non-default user.localbase sysctl value

Reviewed by:	hps (earlier version)
Relnotes:	yes
Differential Revision:	https://reviews.freebsd.org/D27236
2020-11-18 19:44:30 +00:00

75 lines
2.5 KiB
C

/*-
* SPDX-License-Identifier: BSD-2-Clause
*
* Copyright 2020 Stefan Eßer <se@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 REGENTS 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 REGENTS 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/sysctl.h>
#include <sys/limits.h>
#include <stdlib.h>
#include <paths.h>
#include <libutil.h>
#include <unistd.h>
#ifndef _PATH_LOCALBASE
#define _PATH_LOCALBASE "/usr/local"
#endif
const char *
getlocalbase(void)
{
static const int localbase_oid[2] = {CTL_USER, USER_LOCALBASE};
char *tmppath;
size_t tmplen;
static const char *localbase = NULL;
if (issetugid() == 0) {
tmppath = getenv("LOCALBASE");
if (tmppath != NULL && tmppath[0] != '\0')
return (tmppath);
}
if (sysctl(localbase_oid, 2, NULL, &tmplen, NULL, 0) == 0 &&
(tmppath = malloc(tmplen)) != NULL &&
sysctl(localbase_oid, 2, tmppath, &tmplen, NULL, 0) == 0) {
/*
* Check for some other thread already having
* set localbase - this should use atomic ops.
* The amount of memory allocated above may leak,
* if a parallel update in another thread is not
* detected and the non-NULL pointer is overwritten.
*/
if (tmppath[0] != '\0' &&
(volatile const char*)localbase == NULL)
localbase = tmppath;
else
free((void*)tmppath);
return (localbase);
}
return (_PATH_LOCALBASE);
}