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/*
* fhist - file history and comparison tools
* Copyright (C) 1998, 2002, 2008 Peter Miller
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see
* <http://www.gnu.org/licenses/>.
*/
#include <ac/stddef.h>
#include <ac/stdlib.h>
#include <ac/string.h>
#include <env.h>
#include <mem.h>
extern char **environ;
static size_t nenvirons;
static int initialized;
/*
* NAME
* env_initialize - start up environment
*
* SYNOPSIS
* void env_initialize(void);
*
* DESCRIPTION
* The env_initialize function is used to copy all of the environment
* variables into dynamic memory, so that they may be altered by the
* setenv and unsetenv commands.
*/
static void
env_initialize(void)
{
int j;
char **old;
if (initialized)
return;
initialized = 1;
nenvirons = 0;
for (j = 0; environ[j]; ++j)
++nenvirons;
old = environ;
environ = mem_alloc((nenvirons + 1) * sizeof(char *));
for (j = 0; j < nenvirons; ++j)
{
char *cp;
char *was;
was = old[j];
cp = mem_alloc(strlen(was) + 1);
strcpy(cp, was);
environ[j] = cp;
}
environ[nenvirons] = 0;
env_set("SHELL", "/bin/sh");
}
/*
* NAME
* setenv - set environment variable
*
* SYNOPSIS
* void setenv(char *name, char *value);
*
* DESCRIPTION
* The setenv function is used to set the given environment variable to
* the given value.
*
* CAVEAT
* Assumes that the env_initialize function has already been called.
*/
void
env_set(char *name, char *value)
{
size_t name_len;
int j;
char *cp;
if (!initialized)
env_initialize();
cp = 0;
name_len = strlen(name);
for (j = 0; j < nenvirons; ++j)
{
cp = environ[j];
/* assert(cp); */
if
(
name_len <= strlen(cp)
&&
(cp[name_len] == '=' || !cp[name_len])
&&
!memcmp(cp, name, name_len)
)
break;
}
if (environ[j])
{
environ[j] = 0;
if (cp)
mem_free(cp);
}
else
{
size_t nbytes;
nbytes = (nenvirons + 2) * sizeof(char *);
environ = mem_change_size(environ, nbytes);
environ[++nenvirons] = 0;
}
cp = mem_alloc(name_len + strlen(value) + 2);
strcpy(cp, name);
cp[name_len] = '=';
strcpy(cp + name_len + 1, value);
environ[j] = cp;
}
/*
* NAME
* unsetenv - remove environment variable
*
* SYNOPSIS
* void unsetenv(char *name);
*
* DESCRIPTION
* The unsetenv function is used to remove the named variable from the
* environment.
*
* RETURNS
* void
*
* CAVEAT
* Assumes that the env_initialize function has been called already.
*/
void
env_unset(char *name)
{
size_t name_len;
int j;
char *cp;
if (!initialized)
env_initialize();
name_len = strlen(name);
cp = 0;
for (j = 0; j < nenvirons; ++j)
{
cp = environ[j];
/* assert(cp); */
if
(
(cp[name_len] == '=' || !cp[name_len])
&&
!strncmp(cp, name, name_len)
)
break;
}
if (!environ[j])
return;
environ[j] = 0;
if (cp)
mem_free(cp);
--nenvirons;
for ( ; j < nenvirons; ++j)
environ[j] = environ[j + 1];
}
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