X-Git-Url: https://git.ao2.it/visomat-utils.git/blobdiff_plain/f7a9b92e7107a03a92e64a7091f0dea908210cda..0daf8407efa5df5aa5113abcaa2aed1b11e44440:/src/visomat-data-downloader.c

diff --git a/src/visomat-data-downloader.c b/src/visomat-data-downloader.c
index 8cb99e2..1b4cde9 100644
--- a/src/visomat-data-downloader.c
+++ b/src/visomat-data-downloader.c
@@ -21,6 +21,7 @@
 
 #include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
 #include <errno.h>
 #include <unistd.h>
 #include <libusb.h>
@@ -70,7 +71,7 @@ struct pressure  {
 	unsigned int pulses;
 };
 
-static inline int extract_datetime(unsigned char *buffer, struct datetime *d)
+static inline int extract_datetime(uint8_t *buffer, struct datetime *d)
 {
 	int ret;
 
@@ -118,8 +119,8 @@ static void print_record_csv_compat(struct datetime *d, struct pressure *p)
 	printf("\n");
 }
 
-/* TODO separate better decoding data from printing it */
-static int decode_eeprom(unsigned char *buffer,
+/* TODO: it would be better to separate decoding data from printing it */
+static int decode_eeprom(uint8_t *buffer,
 			 unsigned int len,
 			 unsigned int user_mask)
 {
@@ -155,6 +156,13 @@ static int decode_eeprom(unsigned char *buffer,
 			/* user_id and num_records take 3 bytes */
 			i += 3;
 
+			/*
+			 * when there are no records, there is a dummy byte
+			 * which has to be consumed
+			 */
+			if (num_records == 0)
+				i += 1;
+
 			for (j = 0; j < num_records; j++) {
 				ret = extract_datetime(buffer + i, &d);
 				if (ret < 0)
@@ -188,12 +196,12 @@ static int decode_eeprom(unsigned char *buffer,
 	return 0;
 }
 
-static int decode_datetime(unsigned char *buffer, unsigned int len)
+static int decode_datetime(uint8_t *buffer, unsigned int len)
 {
 	int ret;
-	unsigned char code[4] = { 0 };
+	uint8_t code[4] = { 0 };
 	struct datetime d;
-	unsigned char *pbuffer = buffer;
+	uint8_t *pbuffer = buffer;
 
 	if (len != 15)
 		return -EINVAL;
@@ -216,7 +224,7 @@ static int send_command(libusb_device_handle *dev, visomat_command cmd)
 {
 	int ret;
 	int transferred;
-	unsigned char request[5];
+	uint8_t request[5];
 
 	request[0] = STX;
 	request[1] = command_codes[cmd][0];
@@ -235,12 +243,12 @@ static int send_command(libusb_device_handle *dev, visomat_command cmd)
 }
 
 static int get_response(libusb_device_handle *dev,
-			unsigned char *buffer,
+			uint8_t *buffer,
 			unsigned int len)
 {
 	int ret;
 	int transferred;
-	unsigned char response[64] = { 0 };
+	uint8_t response[64] = { 0 };
 	unsigned int i;
 
 	i = 0;
@@ -274,7 +282,7 @@ static int get_response(libusb_device_handle *dev,
 static int visomat_dump_eeprom(visomat_device *dev, unsigned int user_mask)
 {
 	/* Assuming an EEPROM of 1 KiB  */
-	unsigned char buffer[1024] = { 0 };
+	uint8_t buffer[1024] = { 0 };
 	int ret;
 
 	ret = send_command(dev, VISOMAT_CMD_DUMP_EEPROM);
@@ -294,7 +302,7 @@ static int visomat_dump_eeprom(visomat_device *dev, unsigned int user_mask)
 
 static int visomat_get_datetime(visomat_device *dev)
 {
-	unsigned char buffer[255] = { 0 };
+	uint8_t buffer[255] = { 0 };
 	int ret;
 
 	ret = send_command(dev, VISOMAT_CMD_GET_DATETIME);
@@ -316,10 +324,12 @@ int main(void)
 {
 	int ret;
 	libusb_device_handle *dev;
+	int current_configuration;
 
 	ret = libusb_init(NULL);
 	if (ret < 0) {
-		fprintf(stderr, "error (%d): cannot initialize libusb.\n", ret);
+		fprintf(stderr, "libusb_init failed: %s\n",
+			libusb_error_name(ret));
 		goto out;
 	}
 
@@ -329,27 +339,59 @@ int main(void)
 					      VISOMAT_DEVICE_VID,
 					      VISOMAT_DEVICE_PID);
 	if (dev == NULL) {
-		fprintf(stderr, "error (%d): cannot open device.\n", errno);
+		fprintf(stderr, "libusb_open failed: %s\n", strerror(errno));
 		ret = -errno;
 		goto out_libusb_exit;
 	}
 
-	ret = libusb_set_configuration(dev, VISOMAT_CONFIGURATION);
+	current_configuration = -1;
+	ret = libusb_get_configuration(dev, &current_configuration);
 	if (ret < 0) {
-		fprintf(stderr, "error (%d): cannot set configuration %d.\n",
-			ret, VISOMAT_CONFIGURATION);
+		fprintf(stderr, "libusb_get_configuration failed: %s\n",
+			libusb_error_name(ret));
 		goto out_libusb_close;
 	}
 
+	if (current_configuration != VISOMAT_CONFIGURATION) {
+		ret = libusb_set_configuration(dev, VISOMAT_CONFIGURATION);
+		if (ret < 0) {
+			fprintf(stderr, "libusb_set_configuration failed: %s\n",
+				libusb_error_name(ret));
+			fprintf(stderr, "Cannot set configuration %d\n",
+				VISOMAT_CONFIGURATION);
+			goto out_libusb_close;
+		}
+	}
+
 	libusb_set_auto_detach_kernel_driver(dev, 1);
 
 	ret = libusb_claim_interface(dev, VISOMAT_INTERFACE);
 	if (ret < 0) {
-		fprintf(stderr, "error (%d): cannot claim interface %d.\n",
-			ret, VISOMAT_INTERFACE);
+		fprintf(stderr, "libusb_claim_interface failed: %s\n",
+			libusb_error_name(ret));
+		fprintf(stderr, "Cannot claim interface %d\n",
+			VISOMAT_INTERFACE);
 		goto out_libusb_close;
 	}
 
+	/* Checking that the configuration has not changed, as suggested in
+	 * http://libusb.sourceforge.net/api-1.0/caveats.html
+	 */
+	current_configuration = -1;
+	ret = libusb_get_configuration(dev, &current_configuration);
+	if (ret < 0) {
+		fprintf(stderr, "libusb_get_configuration after claim failed: %s\n",
+			libusb_error_name(ret));
+		goto out_libusb_release_interface;
+	}
+
+	if (current_configuration != VISOMAT_CONFIGURATION) {
+		fprintf(stderr, "libusb configuration changed (expected: %d, current: %d)\n",
+			VISOMAT_CONFIGURATION, current_configuration);
+		ret = -EINVAL;
+		goto out_libusb_release_interface;
+	}
+
 	ret = visomat_get_datetime(dev);
 	if (ret < 0)
 		goto out_libusb_release_interface;