freebsd-nq/sys/kern/kern_environment.c
Mike Smith 2084f96c7f Add getenv_int(), specifically for retrieving integer values from kernel
environment variables.  This makes it easy to pass tuning parameters
in from the bootloader.
1999-01-15 17:25:02 +00:00

138 lines
3.4 KiB
C

/*-
* Copyright (c) 1998 Michael Smith
* All rights reserved.
*
* 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.
*
* $Id: kern_environment.c,v 1.3 1998/10/09 21:21:34 msmith Exp $
*/
/*
* The unified bootloader passes us a pointer to a preserved copy of
* bootstrap/kernel environment variables.
* We make these available using sysctl for both in-kernel and
* out-of-kernel consumers.
*
* Note that the current sysctl infrastructure doesn't allow
* dynamic insertion or traversal through handled spaces. Grr.
*/
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/systm.h>
#include <sys/sysctl.h>
#include <sys/libkern.h>
#include <machine/bootinfo.h>
char *kern_envp;
static char *kernenv_next(char *cp);
char *
getenv(char *name)
{
char *cp, *ep;
int len;
for (cp = kern_envp; cp != NULL; cp = kernenv_next(cp)) {
for (ep = cp; (*ep != '=') && (*ep != 0); ep++)
;
len = ep - cp;
if (*ep = '=')
ep++;
if (!strncmp(name, cp, len))
return(ep);
}
return(NULL);
}
/*
* Return an integer value from an environment variable.
*/
int
getenv_int(char *name, int *data)
{
char *value, *vtp;
quad_t iv;
if ((value = getenv(name)) == NULL)
return(0);
iv = strtoq(value, &vtp, 0);
if ((vtp == value) || (*vtp != 0))
return(0);
*data = (int)iv;
return(1);
}
static int
sysctl_kernenv SYSCTL_HANDLER_ARGS
{
int *name = (int *)arg1;
u_int namelen = arg2;
char *cp;
int i, error;
if (kern_envp == NULL)
return(ENOENT);
name++;
namelen--;
if (namelen != 1)
return(EINVAL);
cp = kern_envp;
for (i = 0; i < name[0]; i++) {
cp = kernenv_next(cp);
if (cp == NULL)
break;
}
if (cp == NULL)
return(ENOENT);
error = SYSCTL_OUT(req, cp, strlen(cp) + 1);
return (error);
}
SYSCTL_NODE(_kern, OID_AUTO, environment, CTLFLAG_RD, sysctl_kernenv, "kernel environment space");
/*
* Find the next entry after the one which (cp) falls within, return a
* pointer to its start or NULL if there are no more.
*/
static char *
kernenv_next(char *cp)
{
if (cp != NULL) {
while (*cp != 0)
cp++;
cp++;
if (*cp == 0)
cp = NULL;
}
return(cp);
}