/*
 * Replacement for a missing setenv.
 *
 * Provides the same functionality as the standard library routine setenv for
 * those platforms that don't have it.
 *
 * Written by Russ Allbery <rra@stanford.edu>
 * This work is hereby placed in the public domain by its author.
 */

#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
# 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;
    size_t size;

    if (!overwrite && getenv(name) != NULL)
        return 0;

    /*
     * Allocate memory for the environment string.  We intentionally don't use
     * concat here, or the xmalloc family of allocation routines, since the
     * intention is to provide a replacement for the standard library function
     * which sets errno and returns in the event of a memory allocation
     * failure.
     */
    size = strlen(name) + 1 + strlen(value) + 1;
    envstring = malloc(size);
    if (envstring == NULL)
        return -1;

    /*
     * Build the environment string and add it to the environment using
     * putenv.  Systems without putenv lose, but XPG4 requires it.
     */
    strlcpy(envstring, name, size);
    strlcat(envstring, "=", size);
    strlcat(envstring, value, size);
    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).
     */
}