putenv.c

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/*!
   \file lib/gis/putenv.c
 
   \brief GIS library - environment routines
 
   SPDX-FileCopyrightText: 2001-2009, 2011 GRASS Development Team
   SPDX-License-Identifier: GPL-2.0-or-later
 
   \author Original author CERL
   \author Updated for GRASS7 by Glynn Clements
 */
 
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <grass/config.h>
#include <grass/gis.h>
 
#if !defined(HAVE_PUTENV) && !defined(HAVE_SETENV)
extern char **environ;
#endif
 
/*!
   \brief Sets the UNIX environment variable name to value
 
   \param name env name
   \param value env value
 */
void G_putenv(const char *name, const char *value)
{
    char buf[1024];
 
#if defined(HAVE_PUTENV)
    snprintf(buf, sizeof(buf), "%s=%s", name, value);
    putenv(G_store(buf));
#elif defined(HAVE_SETENV)
    setenv(name, value, 1);
#else
    static int first = 1;
    int i;
    char **newenv;
    char *env;
 
    if (first) {
        for (i = 0; environ[i]; i++)
            ;
        newenv = (char **)G_malloc((i + 1) * sizeof(char *));
        for (i = 0; env = environ[i], env; i++)
            newenv[i] = G_store(env);
        newenv[i] = NULL;
        environ = newenv;
        first = 0;
    }
 
    for (i = 0; env = environ[i], env; i++) {
        char temp[4];
 
        if (sscanf(env, "%[^=]=%1s", buf, temp) < 1)
            continue;
 
        if (strcmp(buf, name) != 0)
            continue;
 
        G_free(env);
        snprintf(buf, sizeof(buf), "%s=%s", name, value);
        environ[i] = G_store(buf);
 
        return;
    }
    environ = (char **)G_realloc(environ, (i + 2) * sizeof(char *));
    snprintf(buf, sizeof(buf), "%s=%s", name, value);
    environ[i++] = G_store(buf);
    environ[i] = NULL;
#endif
}