kern_environment.c revision 52947 
1/*-
2 * Copyright (c) 1998 Michael Smith
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 *
26 * $FreeBSD: head/sys/kern/kern_environment.c 52947 1999-11-07 01:10:30Z mjacob $
27 */
28
29/*
30 * The unified bootloader passes us a pointer to a preserved copy of
31 * bootstrap/kernel environment variables.
32 * We make these available using sysctl for both in-kernel and
33 * out-of-kernel consumers.
34 *
35 * Note that the current sysctl infrastructure doesn't allow
36 * dynamic insertion or traversal through handled spaces.  Grr.
37 */
38
39#include <sys/param.h>
40#include <sys/kernel.h>
41#include <sys/systm.h>
42#include <sys/sysctl.h>
43#include <sys/libkern.h>
44
45char	*kern_envp;
46
47static char	*kernenv_next(char *cp);
48
49char *
50getenv(char *name)
51{
52    char	*cp, *ep;
53    int		len;
54
55    for (cp = kern_envp; cp != NULL; cp = kernenv_next(cp)) {
56	for (ep = cp; (*ep != '=') && (*ep != 0); ep++)
57	    ;
58	len = ep - cp;
59	if (*ep == '=')
60	    ep++;
61	if (!strncmp(name, cp, len))
62	    return(ep);
63    }
64    return(NULL);
65}
66
67/*
68 * Return an integer value from an environment variable.
69 */
70int
71getenv_int(char *name, int *data)
72{
73    quad_t tmp;
74    int rval;
75
76    rval = getenv_quad(name, &tmp);
77    if (rval) {
78	*data = (int) tmp;
79    }
80    return (rval);
81}
82
83/*
84 * Return a quad_t value from an environment variable.
85 */
86quad_t
87getenv_quad(char *name, quad_t *data)
88{
89    const char	*value, *vtp;
90    quad_t	iv;
91
92    if ((value = getenv(name)) == NULL)
93	return(0);
94
95    iv = strtoq(value, &vtp, 0);
96    if ((vtp == value) || (*vtp != 0))
97	return(0);
98
99    *data = iv;
100    return(1);
101}
102
103static int
104sysctl_kernenv SYSCTL_HANDLER_ARGS
105{
106    int		*name = (int *)arg1;
107    u_int	namelen = arg2;
108    char	*cp;
109    int		i, error;
110
111    if (kern_envp == NULL)
112	return(ENOENT);
113
114    name++;
115    namelen--;
116
117    if (namelen != 1)
118	return(EINVAL);
119
120    cp = kern_envp;
121    for (i = 0; i < name[0]; i++) {
122	cp = kernenv_next(cp);
123	if (cp == NULL)
124	    break;
125    }
126
127    if (cp == NULL)
128	return(ENOENT);
129
130    error = SYSCTL_OUT(req, cp, strlen(cp) + 1);
131    return (error);
132}
133
134SYSCTL_NODE(_kern, OID_AUTO, environment, CTLFLAG_RD, sysctl_kernenv, "kernel environment space");
135
136/*
137 * Find the next entry after the one which (cp) falls within, return a
138 * pointer to its start or NULL if there are no more.
139 */
140static char *
141kernenv_next(char *cp)
142{
143    if (cp != NULL) {
144	while (*cp != 0)
145	    cp++;
146	cp++;
147	if (*cp == 0)
148	    cp = NULL;
149    }
150    return(cp);
151}
152
153