sys/arch/ia64/stand/common/environment.c

   1 /*      $NetBSD: environment.c,v 1.2 2009/07/20 04:59:03 kiyohara Exp $ */
   2
   3
   4 /*
   5  * Copyright (c) 1998 Michael Smith.
   6  * All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  */
  29
  30 #include <sys/cdefs.h>
  31
  32 /*
  33  * Manage an environment-like space in which string variables may be stored.
  34  * Provide support for some method-like operations for setting/retrieving
  35  * variables in order to allow some type strength.
  36  */
  37
  38 #include <lib/libsa/stand.h>
  39 #include <lib/libsa/loadfile.h>
  40 #include <lib/libkern/libkern.h>
  41
  42 #include <bootstrap.h>
  43
  44 static void     env_discard(struct env_var *ev);
  45
  46 struct env_var  *environ = NULL;
  47
  48 /*
  49  * Look up (name) and return it's env_var structure.
  50  */
  51 struct env_var  *
  52 env_getenv(const char *name)
  53 {
  54     struct env_var      *ev;
  55
  56     for (ev = environ; ev != NULL; ev = ev->ev_next)
  57         if (!strcmp(ev->ev_name, name))
  58             break;
  59     return(ev);
  60 }
  61
  62 /*
  63  * Some notes:
  64  *
  65  * If the EV_VOLATILE flag is set, a copy of the variable is made.
  66  * If EV_DYNAMIC is set, the variable has been allocated with
  67  * malloc and ownership transferred to the environment.
  68  * If (value) is NULL, the variable is set but has no value.
  69  */
  70 int
  71 env_setenv(const char *name, int flags, const void *value,
  72            ev_sethook_t sethook, ev_unsethook_t unsethook)
  73 {
  74     struct env_var      *ev, *curr, *last;
  75
  76     if ((ev = env_getenv(name)) != NULL) {
  77         /*
  78          * If there's a set hook, let it do the work (unless we are working
  79          * for one already.
  80          */
  81         if ((ev->ev_sethook != NULL) && !(flags & EV_NOHOOK))
  82             return(ev->ev_sethook(ev, flags, value));
  83     } else {
  84
  85         /*
  86          * New variable; create and sort into list
  87          */
  88         ev = alloc(sizeof(struct env_var));
  89         ev->ev_name = strdup(name);
  90         ev->ev_value = NULL;
  91         /* hooks can only be set when the variable is instantiated */
  92         ev->ev_sethook = sethook;
  93         ev->ev_unsethook = unsethook;
  94
  95         /* Sort into list */
  96         ev->ev_prev = NULL;
  97         ev->ev_next = NULL;
  98         /* Search for the record to insert before */
  99         for (last = NULL, curr = environ;
 100              curr != NULL;
 101              last = curr, curr = curr->ev_next) {
 102
 103             if (strcmp(ev->ev_name, curr->ev_name) < 0) {
 104                 if (curr->ev_prev) {
 105                     curr->ev_prev->ev_next = ev;
 106                 } else {
 107                     environ = ev;
 108                 }
 109                 ev->ev_next = curr;
 110                 ev->ev_prev = curr->ev_prev;
 111                 curr->ev_prev = ev;
 112                 break;
 113             }
 114         }
 115         if (curr == NULL) {
 116             if (last == NULL) {
 117                 environ = ev;
 118             } else {
 119                 last->ev_next = ev;
 120                 ev->ev_prev = last;
 121             }
 122         }
 123     }
 124
 125     /* If there is data in the variable, discard it */
 126     if (ev->ev_value != NULL)
 127         free(ev->ev_value);
 128
 129     /* If we have a new value, use it */
 130     if (flags & EV_VOLATILE) {
 131         ev->ev_value = strdup(value);
 132     } else {
 133         ev->ev_value = (void *) value;
 134     }
 135
 136     /* Keep the flag components that are relevant */
 137     ev->ev_flags = flags & (EV_DYNAMIC);
 138
 139     return(0);
 140 }
 141
 142 char *
 143 getenv(const char *name)
 144 {
 145     struct env_var      *ev;
 146
 147     /* Set but no value gives empty string */
 148     if ((ev = env_getenv(name)) != NULL) {
 149         if (ev->ev_value != NULL)
 150             return(ev->ev_value);
 151         return("");
 152     }
 153     return(NULL);
 154 }
 155
 156 int
 157 setenv(const char *name, const char *value, int overwrite)
 158 {
 159     /* No guarantees about state, always assume volatile */
 160     if (overwrite || (env_getenv(name) == NULL))
 161         return(env_setenv(name, EV_VOLATILE, value, NULL, NULL));
 162     return(0);
 163 }
 164
 165 int
 166 putenv(const char *string)
 167 {
 168     char        *value, *copy;
 169     int         result;
 170
 171     copy = strdup(string);
 172     if ((value = strchr(copy, '=')) != NULL)
 173         *(value++) = 0;
 174     result = setenv(copy, value, 1);
 175     free(copy);
 176     return(result);
 177 }
 178
 179 int
 180 unsetenv(const char *name)
 181 {
 182     struct env_var      *ev;
 183     int                 err;
 184
 185     err = 0;
 186     if ((ev = env_getenv(name)) == NULL) {
 187         err = ENOENT;
 188     } else {
 189         if (ev->ev_unsethook != NULL)
 190             err = ev->ev_unsethook(ev);
 191         if (err == 0) {
 192             env_discard(ev);
 193         }
 194     }
 195     return(err);
 196 }
 197
 198 static void
 199 env_discard(struct env_var *ev)
 200 {
 201     if (ev->ev_prev)
 202         ev->ev_prev->ev_next = ev->ev_next;
 203     if (ev->ev_next)
 204         ev->ev_next->ev_prev = ev->ev_prev;
 205     if (environ == ev)
 206         environ = ev->ev_next;
 207     free(ev->ev_name);
 208     if (ev->ev_flags & EV_DYNAMIC)
 209         free(ev->ev_value);
 210     free(ev);
 211 }
 212
 213 int
 214 env_noset(struct env_var *ev, int flags, const void *value)
 215 {
 216     return(EPERM);
 217 }
 218
 219 int
 220 env_nounset(struct env_var *ev)
 221 {
 222     return(EPERM);
 223 }