hp-3478a: Handle NULL dereference in read, write and list.

[libsigrok.git] / src / hardware / hp-3478a / api.c

diff --git a/src/hardware/hp-3478a/api.c b/src/hardware/hp-3478a/api.c
index d4e40338709b36e9366dae623dd2eea15edac7bd..1979c52928d78dfcae41c989668e1e5571f328fa 100644 (file)
--- a/src/hardware/hp-3478a/api.c
+++ b/src/hardware/hp-3478a/api.c
@@ -1,7 +1,7 @@
 /*
  * This file is part of the libsigrok project.
  *
- * Copyright (C) 2017 Frank Stettner <frank-stettner@gmx.net>
+ * Copyright (C) 2017-2021 Frank Stettner <frank-stettner@gmx.net>
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -35,6 +35,7 @@ static const uint32_t devopts[] = {
        SR_CONF_LIMIT_MSEC | SR_CONF_GET | SR_CONF_SET,
        SR_CONF_MEASURED_QUANTITY | SR_CONF_GET | SR_CONF_SET | SR_CONF_LIST,
        SR_CONF_RANGE | SR_CONF_GET | SR_CONF_SET | SR_CONF_LIST,
+       SR_CONF_DIGITS | SR_CONF_GET | SR_CONF_SET | SR_CONF_LIST,
 };
 
 static const struct {
@@ -49,7 +50,6 @@ static const struct {
        {SR_MQ_RESISTANCE, SR_MQFLAG_FOUR_WIRE},
 };
 
-
 static const struct {
        enum sr_mq mq;
        enum sr_mqflag mqflag;
@@ -97,6 +97,16 @@ static const struct {
        {SR_MQ_RESISTANCE, SR_MQFLAG_FOUR_WIRE,     7,   "30MR"},
 };
 
+/** Available digits as strings. */
+static const char *digits[] = {
+       "3.5", "4.5", "5.5",
+};
+
+/** Mapping between devc->spec_digits and digits string. */
+static const char *digits_map[] = {
+       "", "", "", "", "3.5", "4.5", "5.5",
+};
+
 static struct sr_dev_driver hp_3478a_driver_info;
 
 static int create_front_channel(struct sr_dev_inst *sdi, int chan_idx)
@@ -119,6 +129,14 @@ static struct sr_dev_inst *probe_device(struct sr_scpi_dev_inst *scpi)
        struct sr_dev_inst *sdi;
        struct dev_context *devc;
 
+       /*
+        * The device cannot get identified by means of SCPI queries.
+        * Neither shall non-SCPI requests get emitted before reliable
+        * identification of the device. Assume that we only get here
+        * when user specs led us to believe it's safe to communicate
+        * to the expected kind of device.
+        */
+
        sdi = g_malloc0(sizeof(struct sr_dev_inst));
        sdi->vendor = g_strdup("Hewlett-Packard");
        sdi->model = g_strdup("3478A");
@@ -142,6 +160,14 @@ static struct sr_dev_inst *probe_device(struct sr_scpi_dev_inst *scpi)
 
 static GSList *scan(struct sr_dev_driver *di, GSList *options)
 {
+       const char *conn;
+
+       /* Only scan for a device when conn= was specified. */
+       conn = NULL;
+       (void)sr_serial_extract_options(options, &conn, NULL);
+       if (!conn)
+               return NULL;
+
        return sr_scpi_scan(di->context, options, probe_device);
 }
 
@@ -166,6 +192,8 @@ static int config_get(uint32_t key, GVariant **data,
 
        (void)cg;
 
+       if (!sdi)
+               return SR_ERR_ARG;
        devc = sdi->priv;
 
        switch (key) {
@@ -177,7 +205,7 @@ static int config_get(uint32_t key, GVariant **data,
                if (ret != SR_OK)
                        return ret;
                arr[0] = g_variant_new_uint32(devc->measurement_mq);
-               arr[1] = g_variant_new_uint64(devc->measurement_mq_flags);
+               arr[1] = g_variant_new_uint64(devc->measurement_mq_flag);
                *data = g_variant_new_tuple(arr, 2);
                break;
        case SR_CONF_RANGE:
@@ -187,7 +215,7 @@ static int config_get(uint32_t key, GVariant **data,
                range_str = "Auto";
                for (i = 0; i < ARRAY_SIZE(rangeopts); i++) {
                        if (rangeopts[i].mq == devc->measurement_mq &&
-                                       rangeopts[i].mqflag == devc->measurement_mq_flags &&
+                                       rangeopts[i].mqflag == devc->measurement_mq_flag &&
                                        rangeopts[i].range_exp == devc->range_exp) {
                                range_str = rangeopts[i].range_str;
                                break;
@@ -195,6 +223,12 @@ static int config_get(uint32_t key, GVariant **data,
                }
                *data = g_variant_new_string(range_str);
                break;
+       case SR_CONF_DIGITS:
+               ret = hp_3478a_get_status_bytes(sdi);
+               if (ret != SR_OK)
+                       return ret;
+               *data = g_variant_new_string(digits_map[devc->spec_digits]);
+               break;
        default:
                return SR_ERR_NA;
        }
@@ -211,9 +245,12 @@ static int config_set(uint32_t key, GVariant *data,
        GVariant *tuple_child;
        unsigned int i;
        const char *range_str;
+       const char *digits_str;
 
        (void)cg;
 
+       if (!sdi)
+               return SR_ERR_ARG;
        devc = sdi->priv;
 
        switch (key) {
@@ -223,6 +260,7 @@ static int config_set(uint32_t key, GVariant *data,
        case SR_CONF_MEASURED_QUANTITY:
                tuple_child = g_variant_get_child_value(data, 0);
                mq = g_variant_get_uint32(tuple_child);
+               g_variant_unref(tuple_child);
                tuple_child = g_variant_get_child_value(data, 1);
                mq_flags = g_variant_get_uint64(tuple_child);
                g_variant_unref(tuple_child);
@@ -231,12 +269,19 @@ static int config_set(uint32_t key, GVariant *data,
                range_str = g_variant_get_string(data, NULL);
                for (i = 0; i < ARRAY_SIZE(rangeopts); i++) {
                        if (rangeopts[i].mq == devc->measurement_mq &&
-                                       rangeopts[i].mqflag == devc->measurement_mq_flags &&
+                                       rangeopts[i].mqflag == devc->measurement_mq_flag &&
                                        g_strcmp0(rangeopts[i].range_str, range_str) == 0) {
                                return hp_3478a_set_range(sdi, rangeopts[i].range_exp);
                        }
                }
                return SR_ERR_NA;
+       case SR_CONF_DIGITS:
+               digits_str = g_variant_get_string(data, NULL);
+               for (i = 0; i < ARRAY_SIZE(rangeopts); i++) {
+                       if (g_strcmp0(digits_map[i], digits_str) == 0)
+                               return hp_3478a_set_digits(sdi, i);
+               }
+               return SR_ERR_NA;
        default:
                return SR_ERR_NA;
        }
@@ -253,6 +298,10 @@ static int config_list(uint32_t key, GVariant **data,
        GVariant *gvar, *arr[2];
        GVariantBuilder gvb;
 
+       /* Only handle standard keys when no device instance is given. */
+       if (!sdi)
+               return STD_CONFIG_LIST(key, data, sdi, cg, scanopts, drvopts, devopts);
+
        devc = sdi->priv;
 
        switch (key) {
@@ -280,12 +329,15 @@ static int config_list(uint32_t key, GVariant **data,
                g_variant_builder_init(&gvb, G_VARIANT_TYPE_ARRAY);
                for (i = 0; i < ARRAY_SIZE(rangeopts); i++) {
                        if (rangeopts[i].mq == devc->measurement_mq &&
-                                       rangeopts[i].mqflag == devc->measurement_mq_flags) {
+                                       rangeopts[i].mqflag == devc->measurement_mq_flag) {
                                g_variant_builder_add(&gvb, "s", rangeopts[i].range_str);
                        }
                }
                *data = g_variant_builder_end(&gvb);
                break;
+       case SR_CONF_DIGITS:
+               *data = g_variant_new_strv(ARRAY_AND_SIZE(digits));
+               break;
        default:
                return SR_ERR_NA;
        }
@@ -308,7 +360,7 @@ static int dev_acquisition_start(const struct sr_dev_inst *sdi)
         * NOTE: For faster readings, there are some things one can do:
         *     - Turn off the display: sr_scpi_send(scpi, "D3SIGROK").
         *     - Set the line frequency to 60Hz via switch (back of the unit).
-        *     - Set to 3.5 digits measurement (add config key SR_CONF_DIGITS).
+        *     - Set to 3.5 digits measurement.
         */
 
        /* Set to internal trigger. */