scpi: Raise severity when IDN response lacks the serial number field.

[libsigrok.git] / src / scpi / scpi.c

diff --git a/src/scpi/scpi.c b/src/scpi/scpi.c
index 4f72d6e65e01bfc5853efa0cc2cd5615f5676952..f72164a63f177dce0b71dd5d07fbc312566dadd8 100644 (file)
--- a/src/scpi/scpi.c
+++ b/src/scpi/scpi.c
@@ -100,7 +100,7 @@ static const struct sr_scpi_dev_inst *scpi_devs[] = {
 #ifdef HAVE_LIBGPIB
        &scpi_libgpib_dev,
 #endif
-#ifdef HAVE_LIBSERIALPORT
+#ifdef HAVE_SERIAL_COMM
        &scpi_serial_dev, /* Must be last as it matches any resource. */
 #endif
 };
@@ -961,6 +961,7 @@ SR_PRIV int sr_scpi_get_block(struct sr_scpi_dev_inst *scpi,
 {
        int ret;
        GString* response;
+       gsize oldlen;
        char buf[10];
        long llen;
        long datalen;
@@ -990,14 +991,14 @@ SR_PRIV int sr_scpi_get_block(struct sr_scpi_dev_inst *scpi,
        *scpi_response = NULL;
 
        /* Get (the first chunk of) the response. */
-       while (response->len < 2) {
+       do {
                ret = scpi_read_response(scpi, response, timeout);
                if (ret < 0) {
                        g_mutex_unlock(&scpi->scpi_mutex);
                        g_string_free(response, TRUE);
                        return ret;
                }
-       }
+       } while (response->len < 2);
 
        /*
         * SCPI protocol data blocks are preceeded with a length spec.
@@ -1044,25 +1045,33 @@ SR_PRIV int sr_scpi_get_block(struct sr_scpi_dev_inst *scpi,
        g_string_erase(response, 0, 2 + llen);
 
        /*
-        * If the initially assumed length does not cover the data block
-        * length, then re-allocate the buffer size to the now known
-        * length, and keep reading more chunks of response data.
+        * Re-allocate the buffer size to the now known length
+        * and keep reading more chunks of response data.
         */
-       if (response->len < (unsigned long)(datalen)) {
-               int oldlen = response->len;
-               g_string_set_size(response, datalen);
-               g_string_set_size(response, oldlen);
-       }
-
-       while (response->len < (unsigned long)(datalen)) {
-               ret = scpi_read_response(scpi, response, timeout);
-               if (ret < 0) {
-                       g_mutex_unlock(&scpi->scpi_mutex);
-                       g_string_free(response, TRUE);
-                       return ret;
-               }
-               if (ret > 0)
-                       timeout = g_get_monotonic_time() + scpi->read_timeout_us;
+       oldlen = response->len;
+       g_string_set_size(response, datalen);
+       g_string_set_size(response, oldlen);
+
+       if (oldlen < (unsigned long)(datalen)) {
+               do {
+                       oldlen = response->len;
+                       ret = scpi_read_response(scpi, response, timeout);
+
+                       /* On timeout truncate the buffer and send the partial response
+                        * instead of getting stuck on timeouts...
+                        */
+                       if (ret == SR_ERR_TIMEOUT) {
+                               datalen = oldlen;
+                               break;
+                       }
+                       if (ret < 0) {
+                               g_mutex_unlock(&scpi->scpi_mutex);
+                               g_string_free(response, TRUE);
+                               return ret;
+                       }
+                       if (ret > 0)
+                               timeout = g_get_monotonic_time() + scpi->read_timeout_us;
+               } while (response->len < (unsigned long)(datalen));
        }
 
        g_mutex_unlock(&scpi->scpi_mutex);
@@ -1105,15 +1114,24 @@ SR_PRIV int sr_scpi_get_hw_id(struct sr_scpi_dev_inst *scpi,
         * The response to a '*IDN?' is specified by the SCPI spec. It contains
         * a comma-separated list containing the manufacturer name, instrument
         * model, serial number of the instrument and the firmware version.
+        *
+        * BEWARE! Although strictly speaking a smaller field count is invalid,
+        * this implementation also accepts IDN responses with one field less,
+        * and assumes that the serial number is missing. Some GWInstek DMMs
+        * were found to do this. Keep warning about this condition, which may
+        * need more consideration later.
         */
        tokens = g_strsplit(response, ",", 0);
        num_tokens = g_strv_length(tokens);
-       if (num_tokens < 4) {
-               sr_dbg("IDN response not according to spec: %80.s.", response);
+       if (num_tokens < 3) {
+               sr_dbg("IDN response not according to spec: '%s'", response);
                g_strfreev(tokens);
                g_free(response);
                return SR_ERR_DATA;
        }
+       if (num_tokens < 4) {
+               sr_warn("Short IDN response, assume missing serial number.");
+       }
        g_free(response);
 
        hw_info = g_malloc0(sizeof(struct sr_scpi_hw_info));
@@ -1125,8 +1143,13 @@ SR_PRIV int sr_scpi_get_hw_id(struct sr_scpi_dev_inst *scpi,
                hw_info->manufacturer = g_strstrip(g_strdup(idn_substr + 4));
 
        hw_info->model = g_strstrip(g_strdup(tokens[1]));
-       hw_info->serial_number = g_strstrip(g_strdup(tokens[2]));
-       hw_info->firmware_version = g_strstrip(g_strdup(tokens[3]));
+       if (num_tokens < 4) {
+               hw_info->serial_number = g_strdup("Unknown");
+               hw_info->firmware_version = g_strstrip(g_strdup(tokens[2]));
+       } else {
+               hw_info->serial_number = g_strstrip(g_strdup(tokens[2]));
+               hw_info->firmware_version = g_strstrip(g_strdup(tokens[3]));
+       }
 
        g_strfreev(tokens);