iiod: Free XML string after use

Now that iio_context_get_xml() returns a heap-allocated string, we need
to de-allocate it with free() after use.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>

iiod/iiod.c

@@ -101,19 +101,23 @@ static void sig_handler_usr1(int sig)
 
 static void *get_xml_zstd_data(const struct iio_context *ctx, size_t *out_len)
 {
-	const char *xml = iio_context_get_xml(ctx);
-	size_t xml_len = strlen(xml);
+	char *xml = iio_context_get_xml(ctx);
+	size_t len, xml_len = strlen(xml);
 	void *buf;
 #if WITH_ZSTD
 	size_t len;
 	size_t ret;
 
 	len = ZSTD_compressBound(xml_len);
 	buf = malloc(len);
-	if (!buf)
+	if (!buf) {
+		free(xml);
 		return NULL;
+	}
 
 	ret = ZSTD_compress(buf, len, xml, xml_len, 3);
+	free(xml);
+
 	if (ZSTD_isError(ret)) {
 		IIO_WARNING("Unable to compress XML string: %s\n",
 			    ZSTD_getErrorName(xml_len));
@@ -123,10 +127,7 @@ static void *get_xml_zstd_data(const struct iio_context *ctx, size_t *out_len)
 
 	*out_len = ret;
 #else
-	buf = iio_strdup(xml);
-	if (!buf)
-		return NULL;
-
+	buf = xml;
 	*out_len = xml_len;
 #endif