scpi-pps: don't break SCPI devices when scanning for HP-IB devices

[libsigrok.git] / src / hardware / hp-3457a / api.c

diff --git a/src/hardware/hp-3457a/api.c b/src/hardware/hp-3457a/api.c
index 5325224e5e8207e7593b5a0c55765e20866be7e2..f828cfd817f3743c7c764561c8ac8c5737285cff 100644 (file)
--- a/src/hardware/hp-3457a/api.c
+++ b/src/hardware/hp-3457a/api.c
@@ -138,13 +138,15 @@ static struct sr_dev_inst *probe_device(struct sr_scpi_dev_inst *scpi)
        if ((ret != SR_OK) || !response)
                return NULL;
 
-       if (strcmp(response, "HP3457A"))
+       if (strcmp(response, "HP3457A") != 0) {
+               g_free(response);
                return NULL;
+       }
 
        g_free(response);
 
-       devc = g_malloc0(sizeof(struct dev_context));
-       sdi = g_malloc0(sizeof(struct sr_dev_inst));
+       devc = g_malloc0(sizeof(*devc));
+       sdi = g_malloc0(sizeof(*sdi));
        sdi->vendor = g_strdup("Hewlett-Packard");
        sdi->model = g_strdup("3457A");
        sdi->version = get_revision(scpi);
@@ -359,8 +361,13 @@ static int dev_acquisition_start(const struct sr_dev_inst *sdi)
                return SR_ERR_ARG;
        }
 
-       devc->current_channel = devc->active_channels->data;
        devc->num_active_channels = g_slist_length(devc->active_channels);
+       if (!devc->num_active_channels) {
+               sr_err("Need at least one active channel!");
+               g_slist_free(devc->active_channels);
+               return SR_ERR_ARG;
+       }
+       devc->current_channel = devc->active_channels->data;
 
        hp_3457a_select_input(sdi, front_selected ? CONN_FRONT : CONN_REAR);