kern_environment.c revision 85385 
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 85385 2001-10-23 22:34:36Z jhb $
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
49/*
50 * Look up an environment variable by name.
51 */
52char *
53getenv(const char *name)
54{
55    char	*cp, *ep;
56    int		len;
57
58    for (cp = kern_envp; cp != NULL; cp = kernenv_next(cp)) {
59	for (ep = cp; (*ep != '=') && (*ep != 0); ep++)
60	    ;
61	len = ep - cp;
62	if (*ep == '=')
63	    ep++;
64	if (!strncmp(name, cp, len))
65	    return(ep);
66    }
67    return(NULL);
68}
69
70/*
71 * Return a string value from an environment variable.
72 */
73int
74getenv_string(const char *name, char *data, int size)
75{
76    char *tmp;
77
78    tmp = getenv(name);
79    if (tmp == NULL) {
80	strncpy(data, tmp, size);
81	data[size - 1] = 0;
82	return (1);
83    } else
84	return (0);
85}
86
87/*
88 * Return an integer value from an environment variable.
89 */
90int
91getenv_int(const char *name, int *data)
92{
93    quad_t tmp;
94    int rval;
95
96    rval = getenv_quad(name, &tmp);
97    if (rval) {
98	*data = (int) tmp;
99    }
100    return (rval);
101}
102
103/*
104 * Return a quad_t value from an environment variable.
105 */
106int
107getenv_quad(const char *name, quad_t *data)
108{
109    const char	*value;
110    char	*vtp;
111    quad_t	iv;
112
113    if ((value = getenv(name)) == NULL)
114	return(0);
115
116    iv = strtoq(value, &vtp, 0);
117    if ((vtp == value) || (*vtp != '\0'))
118	return(0);
119
120    *data = iv;
121    return(1);
122}
123
124/*
125 * Export for userland.  See kenv(1) specifically.
126 */
127static int
128sysctl_kernenv(SYSCTL_HANDLER_ARGS)
129{
130    int		*name = (int *)arg1;
131    u_int	namelen = arg2;
132    char	*cp;
133    int		i, error;
134
135    if (kern_envp == NULL)
136	return(ENOENT);
137
138    name++;
139    namelen--;
140
141    if (namelen != 1)
142	return(EINVAL);
143
144    cp = kern_envp;
145    for (i = 0; i < name[0]; i++) {
146	cp = kernenv_next(cp);
147	if (cp == NULL)
148	    break;
149    }
150
151    if (cp == NULL)
152	return(ENOENT);
153
154    error = SYSCTL_OUT(req, cp, strlen(cp) + 1);
155    return (error);
156}
157
158SYSCTL_NODE(_kern, OID_AUTO, environment, CTLFLAG_RD, sysctl_kernenv, "kernel environment space");
159
160/*
161 * Find the next entry after the one which (cp) falls within, return a
162 * pointer to its start or NULL if there are no more.
163 */
164static char *
165kernenv_next(char *cp)
166{
167    if (cp != NULL) {
168	while (*cp != 0)
169	    cp++;
170	cp++;
171	if (*cp == 0)
172	    cp = NULL;
173    }
174    return(cp);
175}
176
177void
178tunable_int_init(void *data)
179{
180	struct tunable_int *d = (struct tunable_int *)data;
181
182	TUNABLE_INT_FETCH(d->path, d->var);
183}
184
185void
186tunable_quad_init(void *data)
187{
188	struct tunable_quad *d = (struct tunable_quad *)data;
189
190	TUNABLE_QUAD_FETCH(d->path, d->var);
191}
192
193void
194tunable_str_init(void *data)
195{
196	struct tunable_str *d = (struct tunable_str *)data;
197
198	TUNABLE_STR_FETCH(d->path, d->var, d->size);
199}
200