sys/kern/kern_environment.c

   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: src/sys/kern/kern_environment.c,v 1.10.2.7 2002/05/07 09:57:16 bde Exp $
  27  * $DragonFly: src/sys/kern/kern_environment.c,v 1.2 2003/06/17 04:28:41 dillon Exp $
  28  */
  29
  30 /*
  31  * The unified bootloader passes us a pointer to a preserved copy of
  32  * bootstrap/kernel environment variables.
  33  * We make these available using sysctl for both in-kernel and
  34  * out-of-kernel consumers.
  35  *
  36  * Note that the current sysctl infrastructure doesn't allow
  37  * dynamic insertion or traversal through handled spaces.  Grr.
  38  */
  39
  40 #include <sys/param.h>
  41 #include <sys/kernel.h>
  42 #include <sys/systm.h>
  43 #include <sys/sysctl.h>
  44 #include <sys/libkern.h>
  45
  46 char    *kern_envp;
  47
  48 static char     *kernenv_next(char *cp);
  49
  50 /*
  51  * Look up an environment variable by name.
  52  */
  53 char *
  54 getenv(const char *name)
  55 {
  56     char        *cp, *ep;
  57     int         len;
  58
  59     for (cp = kern_envp; cp != NULL; cp = kernenv_next(cp)) {
  60         for (ep = cp; (*ep != '=') && (*ep != 0); ep++)
  61             ;
  62         if (*ep != '=')
  63             continue;
  64         len = ep - cp;
  65         ep++;
  66         if (!strncmp(name, cp, len) && name[len] == 0)
  67             return(ep);
  68     }
  69     return(NULL);
  70 }
  71
  72 /*
  73  * Return a string value from an environment variable.
  74  */
  75 int
  76 getenv_string(const char *name, char *data, int size)
  77 {
  78     char *tmp;
  79
  80     tmp = getenv(name);
  81     if (tmp != NULL) {
  82         strncpy(data, tmp, size);
  83         data[size - 1] = 0;
  84         return (1);
  85     } else
  86         return (0);
  87 }
  88
  89 /*
  90  * Return an integer value from an environment variable.
  91  */
  92 int
  93 getenv_int(const char *name, int *data)
  94 {
  95     quad_t tmp;
  96     int rval;
  97
  98     rval = getenv_quad(name, &tmp);
  99     if (rval) {
 100         *data = (int) tmp;
 101     }
 102     return (rval);
 103 }
 104
 105 /*
 106  * Return a quad_t value from an environment variable.
 107  */
 108 int
 109 getenv_quad(const char *name, quad_t *data)
 110 {
 111     const char  *value;
 112     char        *vtp;
 113     quad_t      iv;
 114
 115     if ((value = getenv(name)) == NULL)
 116         return(0);
 117
 118     iv = strtoq(value, &vtp, 0);
 119     if ((vtp == value) || (*vtp != '\0'))
 120         return(0);
 121
 122     *data = iv;
 123     return(1);
 124 }
 125
 126 static int
 127 sysctl_kernenv(SYSCTL_HANDLER_ARGS)
 128 {
 129     int         *name = (int *)arg1;
 130     u_int       namelen = arg2;
 131     char        *cp;
 132     int         i, error;
 133
 134     if (kern_envp == NULL)
 135         return(ENOENT);
 136
 137     name++;
 138     namelen--;
 139
 140     if (namelen != 1)
 141         return(EINVAL);
 142
 143     cp = kern_envp;
 144     for (i = 0; i < name[0]; i++) {
 145         cp = kernenv_next(cp);
 146         if (cp == NULL)
 147             break;
 148     }
 149
 150     if (cp == NULL)
 151         return(ENOENT);
 152
 153     error = SYSCTL_OUT(req, cp, strlen(cp) + 1);
 154     return (error);
 155 }
 156
 157 SYSCTL_NODE(_kern, OID_AUTO, environment, CTLFLAG_RD, sysctl_kernenv, "kernel environment space");
 158
 159 /*
 160  * Find the next entry after the one which (cp) falls within, return a
 161  * pointer to its start or NULL if there are no more.
 162  */
 163 static char *
 164 kernenv_next(char *cp)
 165 {
 166     if (cp != NULL) {
 167         while (*cp != 0)
 168             cp++;
 169         cp++;
 170         if (*cp == 0)
 171             cp = NULL;
 172     }
 173     return(cp);
 174 }
 175
 176 void
 177 tunable_int_init(void *data)
 178 {
 179         struct tunable_int *d = (struct tunable_int *)data;
 180
 181         TUNABLE_INT_FETCH(d->path, d->var);
 182 }
 183
 184 void
 185 tunable_quad_init(void *data)
 186 {
 187         struct tunable_quad *d = (struct tunable_quad *)data;
 188
 189         TUNABLE_QUAD_FETCH(d->path, d->var);
 190 }
 191
 192 void
 193 tunable_str_init(void *data)
 194 {
 195         struct tunable_str *d = (struct tunable_str *)data;
 196
 197         TUNABLE_STR_FETCH(d->path, d->var, d->size);
 198 }
 199