Function kern_setenv

freebsd/kern/kern_environment.c:548–592

* Set an environment variable by name. */

 * Set an environment variable by name.
 */
int
kern_setenv(const char *name, const char *value)
{
	char *buf, *cp, *oldenv;
	int namelen, vallen, i;

	if (!dynamic_kenv && md_env_len > 0)
		return (setenv_static(name, value));

	KENV_CHECK;

	namelen = strlen(name) + 1;
	if (namelen > KENV_MNAMELEN + 1)
		return (-1);
	vallen = strlen(value) + 1;
	if (vallen > kenv_mvallen + 1)
		return (-1);
	buf = malloc(namelen + vallen, M_KENV, M_WAITOK);
	sprintf(buf, "%s=%s", name, value);

	mtx_lock(&kenv_lock);
	cp = _getenv_dynamic(name, &i);
	if (cp != NULL) {
		oldenv = kenvp[i];
		kenvp[i] = buf;
		mtx_unlock(&kenv_lock);
		free(oldenv, M_KENV);
	} else {
		/* We add the option if it wasn't found */
		for (i = 0; (cp = kenvp[i]) != NULL; i++)
			;

		/* Bounds checking */
		if (i < 0 || i >= KENV_SIZE) {
			free(buf, M_KENV);
			mtx_unlock(&kenv_lock);
			return (-1);
		}

		kenvp[i] = buf;
		kenvp[i + 1] = NULL;
		mtx_unlock(&kenv_lock);
	}
	return (0);
}

/*
 * Unset an environment variable string.