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/*
* Copyright (c) 1998 Michael Smith.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
/*
* Manage an environment-like space in which string variables may be stored.
* Provide support for some method-like operations for setting/retrieving
* variables in order to allow some type strength.
*/
#include "stand.h"
#include <string.h>
static void env_discard(struct env_var *ev);
struct env_var *environ = NULL;
/*
* Look up (name) and return it's env_var structure.
*/
struct env_var *
env_getenv(const char *name)
{
struct env_var *ev;
for (ev = environ; ev != NULL; ev = ev->ev_next)
if (!strcmp(ev->ev_name, name))
break;
return(ev);
}
/*
* Some notes:
*
* If the EV_VOLATILE flag is set, a copy of the variable is made.
* If EV_DYNAMIC is set, the variable has been allocated with
* malloc and ownership transferred to the environment.
* If (value) is NULL, the variable is set but has no value.
*/
int
env_setenv(const char *name, int flags, const void *value,
ev_sethook_t sethook, ev_unsethook_t unsethook)
{
struct env_var *ev, *curr, *last;
if ((ev = env_getenv(name)) != NULL) {
/*
* If there's a set hook, let it do the work (unless we are working
* for one already.
*/
if ((ev->ev_sethook != NULL) && !(flags & EV_NOHOOK))
return(ev->ev_sethook(ev, flags, value));
} else {
/*
* New variable; create and sort into list
*/
ev = malloc(sizeof(struct env_var));
ev->ev_name = strdup(name);
ev->ev_value = NULL;
/* hooks can only be set when the variable is instantiated */
ev->ev_sethook = sethook;
ev->ev_unsethook = unsethook;
/* Sort into list */
ev->ev_prev = NULL;
ev->ev_next = NULL;
/* Search for the record to insert before */
for (last = NULL, curr = environ;
curr != NULL;
last = curr, curr = curr->ev_next) {
if (strcmp(ev->ev_name, curr->ev_name) < 0) {
if (curr->ev_prev) {
curr->ev_prev->ev_next = ev;
} else {
environ = ev;
}
ev->ev_next = curr;
ev->ev_prev = curr->ev_prev;
curr->ev_prev = ev;
break;
}
}
if (curr == NULL) {
if (last == NULL) {
environ = ev;
} else {
last->ev_next = ev;
ev->ev_prev = last;
}
}
}
/* If there is data in the variable, discard it */
if (ev->ev_value != NULL)
free(ev->ev_value);
/* If we have a new value, use it */
if (flags & EV_VOLATILE) {
ev->ev_value = strdup(value);
} else {
ev->ev_value = (char *)value;
}
/* Keep the flag components that are relevant */
ev->ev_flags = flags & (EV_DYNAMIC);
return(0);
}
char *
getenv(const char *name)
{
struct env_var *ev;
/* Set but no value gives empty string */
if ((ev = env_getenv(name)) != NULL) {
if (ev->ev_value != NULL)
return(ev->ev_value);
return("");
}
return(NULL);
}
int
setenv(const char *name, const char *value, int overwrite)
{
/* No guarantees about state, always assume volatile */
if (overwrite || (env_getenv(name) == NULL))
return(env_setenv(name, EV_VOLATILE, value, NULL, NULL));
return(0);
}
int
putenv(const char *string)
{
char *value, *copy;
int result;
copy = strdup(string);
if ((value = strchr(copy, '=')) != NULL)
*(value++) = 0;
result = setenv(copy, value, 1);
free(copy);
return(result);
}
int
unsetenv(const char *name)
{
struct env_var *ev;
int err;
err = 0;
if ((ev = env_getenv(name)) == NULL) {
err = ENOENT;
} else {
if (ev->ev_unsethook != NULL)
err = ev->ev_unsethook(ev);
if (err == 0) {
env_discard(ev);
}
}
return(err);
}
static void
env_discard(struct env_var *ev)
{
if (ev->ev_prev)
ev->ev_prev->ev_next = ev->ev_next;
if (ev->ev_next)
ev->ev_next->ev_prev = ev->ev_prev;
if (environ == ev)
environ = ev->ev_next;
free(ev->ev_name);
if (ev->ev_flags & EV_DYNAMIC)
free(ev->ev_value);
free(ev);
}
int
env_noset(struct env_var *ev __unused, int flags __unused,
const void *value __unused)
{
return(EPERM);
}
int
env_nounset(struct env_var *ev __unused)
{
return(EPERM);
}
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