kern_environment.c revision 40090 
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 *	$Id$
27
28/*
29 * The unified bootloader passes us a pointer to a preserved copy of
30 * bootstrap/kernel environment variables.
31 * We make these available using sysctl for both in-kernel and
32 * out-of-kernel consumers.
33 *
34 * Note that the current sysctl infrastructure doesn't allow
35 * dynamic insertion or traversal through handled spaces.  Grr.
36 */
37
38#include <sys/param.h>
39#include <sys/kernel.h>
40#include <sys/systm.h>
41#include <sys/sysctl.h>
42#include <sys/libkern.h>
43#include <machine/bootinfo.h>
44
45char	*kern_envp;
46
47static char	*kernenv_next(char *cp);
48
49static void
50kernenv_init(void* arg)
51{
52    if (bootinfo.bi_envp != 0)
53	kern_envp = (char *)bootinfo.bi_envp;
54}
55
56SYSINIT(kernenv, SI_SUB_CONSOLE, SI_ORDER_FIRST, kernenv_init, 0);
57
58char *
59getenv(char *name)
60{
61    char	*cp, *ep;
62    int		len;
63
64    for (cp = kern_envp; cp != NULL; cp = kernenv_next(cp)) {
65	for (ep = cp; (*ep != '=') && (*ep != 0); ep++)
66	    ;
67	len = ep - cp;
68	if (*ep = '=')
69	    ep++;
70	if (!strncmp(name, cp, len))
71	    return(ep);
72    }
73    return(NULL);
74}
75
76
77static int
78sysctl_kernenv SYSCTL_HANDLER_ARGS
79{
80    int		*name = (int *)arg1;
81    u_int	namelen = arg2;
82    char	*cp;
83    int		i, error;
84
85    if (kern_envp == NULL)
86	return(ENOENT);
87
88    name++;
89    namelen--;
90
91    if (namelen != 1)
92	return(EINVAL);
93
94    cp = kern_envp;
95    for (i = 0; i < name[0]; i++) {
96	cp = kernenv_next(cp);
97	if (cp == NULL)
98	    break;
99    }
100
101    if (cp == NULL)
102	return(ENOENT);
103
104    error = SYSCTL_OUT(req, cp, strlen(cp) + 1);
105    return (error);
106}
107
108SYSCTL_NODE(_kern, OID_AUTO, environment, CTLFLAG_RD, sysctl_kernenv, "kernel environment space");
109
110/*
111 * Find the next entry after the one which (cp) falls within, return a
112 * pointer to its start or NULL if there are no more.
113 */
114static char *
115kernenv_next(char *cp)
116{
117    if (cp != NULL) {
118	while (*cp != 0)
119	    cp++;
120	cp++;
121	if (*cp == 0)
122	    cp = NULL;
123    }
124    return(cp);
125}
126
127