kern_environment.c revision 43299 
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 *	$Id: kern_environment.c,v 1.4 1999/01/15 17:24:56 msmith Exp $
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#include <machine/bootinfo.h>
45
46char	*kern_envp;
47
48static char	*kernenv_next(char *cp);
49
50char *
51getenv(char *name)
52{
53    char	*cp, *ep;
54    int		len;
55
56    for (cp = kern_envp; cp != NULL; cp = kernenv_next(cp)) {
57	for (ep = cp; (*ep != '=') && (*ep != 0); ep++)
58	    ;
59	len = ep - cp;
60	if (*ep == '=')
61	    ep++;
62	if (!strncmp(name, cp, len))
63	    return(ep);
64    }
65    return(NULL);
66}
67
68/*
69 * Return an integer value from an environment variable.
70 */
71int
72getenv_int(char *name, int *data)
73{
74    char	*value, *vtp;
75    quad_t	iv;
76
77    if ((value = getenv(name)) == NULL)
78	return(0);
79
80    iv = strtoq(value, &vtp, 0);
81    if ((vtp == value) || (*vtp != 0))
82	return(0);
83
84    *data = (int)iv;
85    return(1);
86}
87
88static int
89sysctl_kernenv SYSCTL_HANDLER_ARGS
90{
91    int		*name = (int *)arg1;
92    u_int	namelen = arg2;
93    char	*cp;
94    int		i, error;
95
96    if (kern_envp == NULL)
97	return(ENOENT);
98
99    name++;
100    namelen--;
101
102    if (namelen != 1)
103	return(EINVAL);
104
105    cp = kern_envp;
106    for (i = 0; i < name[0]; i++) {
107	cp = kernenv_next(cp);
108	if (cp == NULL)
109	    break;
110    }
111
112    if (cp == NULL)
113	return(ENOENT);
114
115    error = SYSCTL_OUT(req, cp, strlen(cp) + 1);
116    return (error);
117}
118
119SYSCTL_NODE(_kern, OID_AUTO, environment, CTLFLAG_RD, sysctl_kernenv, "kernel environment space");
120
121/*
122 * Find the next entry after the one which (cp) falls within, return a
123 * pointer to its start or NULL if there are no more.
124 */
125static char *
126kernenv_next(char *cp)
127{
128    if (cp != NULL) {
129	while (*cp != 0)
130	    cp++;
131	cp++;
132	if (*cp == 0)
133	    cp = NULL;
134    }
135    return(cp);
136}
137
138