/*
 * Replacement for a missing setenv.
 *
 * Provides the same functionality as the standard library routine setenv for
 * those platforms that don't have it.
 *
 * The canonical version of this file is maintained in the rra-c-util package,
 * which can be found at <https://www.eyrie.org/~eagle/software/rra-c-util/>.
 *
 * Written by Russ Allbery <eagle@eyrie.org>
 * Copyright 2000, 2014 Russ Allbery <eagle@eyrie.org>
 * Copyright 2008, 2011-2012, 2014
 *     The Board of Trustees of the Leland Stanford Junior University
 *
 * Copying and distribution of this file, with or without modification, are
 * permitted in any medium without royalty provided the copyright notice and
 * this notice are preserved.  This file is offered as-is, without any
 * warranty.
 *
 * SPDX-License-Identifier: FSFAP
 */

#include <config.h>
#include <portable/system.h>

/*
 * If we're running the test suite, rename setenv to avoid conflicts with
 * the system version.
 */
#if TESTING
# undef setenv
# define setenv test_setenv
int test_setenv(const char *, const char *, int);
#endif

int
setenv(const char *name, const char *value, int overwrite)
{
    char *envstring;

    /* Do nothing if not overwriting and the variable is already set. */
    if (!overwrite && getenv(name) != NULL)
        return 0;

    /*
     * Build the environment string and add it to the environment using
     * putenv.  Systems without putenv lose, but XPG4 requires it.
     *
     * We intentionally don't use the xmalloc family of allocation routines
     * here, since the intention is to provide a replacement for the standard
     * library function that sets errno and returns in the event of a memory
     * allocation failure.
     */
    if (asprintf(&envstring, "%s=%s", name, value) < 0)
        return -1;
    return putenv(envstring);

    /*
     * Note that the memory allocated is not freed.  This is intentional; many
     * implementations of putenv assume that the string passed to putenv will
     * never be freed and don't make a copy of it.  Repeated use of this
     * function will therefore leak memory, since most implementations of
     * putenv also don't free strings removed from the environment (due to
     * being overwritten).
     */
}