fix issues pointed out by no-sign-compare removal

By default comparing signed with unsigned, the compiler converts the
signed value to unsigned, this can cause problems sometimes, as that
would mean -1 > 2U.

In channel.c, context.c, device.c the lengths of strings to a negative
number, so cast to a signed number in all cases.

In dns_sd.c, local.c, tests/iio_stresstest.c we had an iterator, that
was signed, that should have been unsigned (now it is).

In local.c:get_rel_timeout_ms we move the comparision to signed.

in local.c, while pointers are unsigned integers, subtraction of two
pointers are ptrdiff_t, or a signed integer. Since we are just measuring
length of a string, cast to unsigned.

Signed-off-by: Robin Getz <[email protected]>

channel.c

@@ -293,14 +293,14 @@ char * iio_channel_get_xml(const struct iio_channel *chn, size_t *length)
 		len = eptr - ptr;
 	}
 
-	if (chn->is_scan_element && len > scan_element_len) {
+	if (chn->is_scan_element && len > (ssize_t) scan_element_len) {
 		memcpy(ptr, scan_element, scan_element_len); /* Flawfinder: ignore */
 		ptr += scan_element_len;
 		len -= scan_element_len;
 	}
 
 	for (i = 0; i < chn->nb_attrs; i++) {
-		if (len > attrs_len[i]) {
+		if (len > (ssize_t) attrs_len[i]) {
 			memcpy(ptr, attrs[i], attrs_len[i]); /* Flawfinder: ignore */
 			ptr += attrs_len[i];
 			len -= attrs_len[i];

context.c

@@ -116,7 +116,7 @@ char * iio_context_create_xml(const struct iio_context *ctx)
 	}
 
 	for (i = 0; i < ctx->nb_devices; i++) {
-		if (len > devices_len[i]) {
+		if (len > (ssize_t) devices_len[i]) {
 			memcpy(ptr, devices[i], devices_len[i]); /* Flawfinder: ignore */
 			ptr += devices_len[i];
 			len -= devices_len[i];

device.c

@@ -173,7 +173,7 @@ char * iio_device_get_xml(const struct iio_device *dev, size_t *length)
 	}
 
 	for (i = 0; i < dev->nb_channels; i++) {
-		if (len > channels_len[i]) {
+		if (len > (ssize_t) channels_len[i]) {
 			memcpy(ptr, channels[i], channels_len[i]); /* Flawfinder: ignore */
 			ptr += channels_len[i];
 			len -= channels_len[i];
@@ -185,7 +185,7 @@ char * iio_device_get_xml(const struct iio_device *dev, size_t *length)
 	free(channels_len);
 
 	for (i = 0; i < dev->nb_attrs; i++) {
-		if (len > attrs_len[i]) {
+		if (len > (ssize_t) attrs_len[i]) {
 			memcpy(ptr, attrs[i], attrs_len[i]); /* Flawfinder: ignore */
 			ptr += attrs_len[i];
 			len -= attrs_len[i];
@@ -197,7 +197,7 @@ char * iio_device_get_xml(const struct iio_device *dev, size_t *length)
 	free(attrs_len);
 
 	for (i = 0; i < dev->nb_buffer_attrs; i++) {
-		if (len > buffer_attrs_len[i]) {
+		if (len > (ssize_t) buffer_attrs_len[i]) {
 			memcpy(ptr, buffer_attrs[i], buffer_attrs_len[i]); /* Flawfinder: ignore */
 			ptr += buffer_attrs_len[i];
 			len -= buffer_attrs_len[i];
@@ -209,7 +209,7 @@ char * iio_device_get_xml(const struct iio_device *dev, size_t *length)
 	free(buffer_attrs_len);
 
 	for (i = 0; i < dev->nb_debug_attrs; i++) {
-		if (len > debug_attrs_len[i]) {
+		if (len > (ssize_t) debug_attrs_len[i]) {
 			memcpy(ptr, debug_attrs[i], debug_attrs_len[i]); /* Flawfinder: ignore */
 			ptr += debug_attrs_len[i];
 			len -= debug_attrs_len[i];

dns_sd.c

@@ -74,7 +74,7 @@ static int dnssd_fill_context_info(struct iio_context_info *info,
 	char uri[sizeof("ip:") + MAXHOSTNAMELEN + sizeof (":65535") + 1];
 	char description[255], *p;
 	const char *hw_model, *serial;
-	int i;
+	unsigned int i;
 
 	ctx = network_create_context(addr_str);
 	if (!ctx) {

iiod/ops.c

@@ -674,7 +674,7 @@ static void rw_thd(struct thread_pool *pool, void *d)
 
 				if (ret < 0 || thd->nb < sample_size)
 					signal_thread(thd, (ret < 0) ?
-							ret : thd->nb);
+							ret : (ssize_t) thd->nb);
 			}
 
 			pthread_mutex_unlock(&entry->thdlist_lock);
@@ -820,7 +820,7 @@ static ssize_t rw_buffer(struct parser_pdata *pdata,
 		ret = thd->err;
 	pthread_mutex_unlock(&entry->thdlist_lock);
 
-	if (ret > 0 && ret < nb)
+	if (ret > 0 && ret < (ssize_t) nb)
 		print_value(thd->pdata, 0);
 
 	IIO_DEBUG("Exiting rw_buffer with code %li\n", (long) ret);

local.c

@@ -266,7 +266,7 @@ static int get_rel_timeout_ms(struct timespec *start, unsigned int timeout_rel)
 	diff_ms = (now.tv_sec - start->tv_sec) * 1000;
 	diff_ms += (now.tv_nsec - start->tv_nsec) / 1000000;
 
-	if (diff_ms >= timeout_rel) /* Expired */
+	if (diff_ms >= (int) timeout_rel) /* Expired */
 		return 0;
 	if (diff_ms > 0) /* Should never be false, but lets be safe */
 		timeout_rel -= diff_ms;
@@ -1499,7 +1499,7 @@ static unsigned int is_global_attr(struct iio_channel *chn, const char *attr)
 		unsigned int len2 = ptr - dashptr - 1;
 		const char*  iddashptr = strchr(chn->id, '-');
 		if (iddashptr && strlen(iddashptr + 1) > len2 &&
-			iddashptr - chn->id > len1 &&
+			(unsigned int)(iddashptr - chn->id) > len1 &&
 			chn->id[len1] >= '0' && chn->id[len1] <= '9' &&
 			!strncmp(chn->id, attr, len1) &&
 			iddashptr[len2 + 1] >= '0' && iddashptr[len2 + 1] <= '9' &&
@@ -1612,7 +1612,7 @@ static int add_buffer_attr(void *d, const char *path)
 	struct iio_device *dev = (struct iio_device *) d;
 	const char *name = strrchr(path, '/') + 1;
 	char **attrs, *attr;
-	int i;
+	unsigned int i;
 
 	for (i = 0; i < ARRAY_SIZE(buffer_attrs_reserved); i++)
 		if (!strcmp(buffer_attrs_reserved[i], name))

tests/iio_stresstest.c

@@ -604,7 +604,7 @@ int main(int argc, char **argv)
 		}
 
 		/* Calculate some stats about the threads */
-		int a =0, b = 0;
+		unsigned int a =0, b = 0;
 		c = 0;
 		for (i = 0; i < info.num_threads; i++) {
 			a+= info.starts[i];

usb.c

@@ -1106,7 +1106,7 @@ struct iio_context * usb_create_context_from_uri(const char *uri)
 	if (bus < 0 || address < 0 || interface < 0)
 		goto err_bad_uri;
 
-	if (bus > UINT_MAX || address > UINT8_MAX || interface > UINT8_MAX)
+	if (bus > (long) UINT_MAX || address > UINT8_MAX || interface > UINT8_MAX)
 		goto err_bad_uri;
 
 	return usb_create_context((unsigned int) bus,