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/* xputenv.c: set an environment variable without return. */
/* Copyright 1993-98, 2008 Karl Berry.
Copyright 2003-05 Olaf Weber.
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with this library; if not, see <http://www.gnu.org/licenses/>. */
#include <kpathsea/config.h>
#ifdef WIN32
#include <stdlib.h>
#else
/* Avoid implicit declaration warning. But since some systems do
declare it, don't use a prototype, for fear of conflicts. */
extern int putenv ();
#endif /* not WIN32 */
/* These record the strings we've set and have to keep around.
* This function can be called many times during a run, and this
* allows us to reclaim memory we allocated.
*/
static char **saved_env;
static int saved_count;
/*
* We have different arguments from the "standard" function. A separate
* var and value tends to be much more practical.
*
* The standards for putenv are clear: put the passed string into the
* environment, and if you alter that string, the environment changes.
* Of course various implementations are broken in a number of ways,
* which include making copies of the passed string, and more.
*/
void
xputenv(const char *var, const char *value)
{
char *cur_item;
char *old_item;
char *new_item;
size_t var_lim;
int cur_loc;
/* kpse_debug2(KPSE_DEBUG_VARS, "kpse_putenv($%s,%s)", var, value); */
old_item = NULL;
cur_item = concat3(var, "=", value);
/* Include '=' in length. */
var_lim = strlen(var) + 1;
/* Have we stored something for this value already? */
for (cur_loc = 0; cur_loc != saved_count; ++cur_loc) {
if (strncmp(saved_env[cur_loc], cur_item, var_lim) == 0) {
/* Get the old value. We need this is case another part
* of the program didn't use us to change the environment.
*/
old_item = getenv(var);
break;
}
}
if (old_item && strcmp(old_item, cur_item+var_lim) == 0) {
/* Set same value as is in environment, don't bother to set. */
free(cur_item);
return;
} else {
/* We set a different value. */
if (putenv(cur_item) < 0)
FATAL1("putenv(%s)", cur_item);
/* Get the new string. */
new_item = getenv(var);
if (new_item != cur_item+var_lim) {
/* Our new string isn't used, don't keep it around. */
free(cur_item);
return;
}
}
/* If we get here, it means getenv() returned a reference to cur_item.
* So we save cur_item, and free the old string we also owned.
*/
if (cur_loc == saved_count) {
/* No old string. */
saved_count++;
saved_env = XRETALLOC(saved_env, saved_count, char *);
} else {
/* We owned the old string. */
free(saved_env[cur_loc]);
}
saved_env[cur_loc] = cur_item;
return;
}
/* A special case for setting a variable to a numeric value
(specifically, KPATHSEA_DPI). We don't need to dynamically allocate
and free the string for the number, since it's saved as part of the
environment value. */
void
xputenv_int P2C(const_string, var_name, int, num)
{
char str[MAX_INT_LENGTH];
sprintf (str, "%d", num);
xputenv (var_name, str);
}
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