local: Track buffer attributes

Track attributes within the buffer/ sysfs directory. These attributes
include watermarks, fifo controls, etc.

Signed-off-by: Matt Fornero <matt.fornero@mathworks.com>

device.c

@@ -405,6 +405,10 @@ void free_device(struct iio_device *dev)
 		free(dev->attrs[i]);
 	if (dev->nb_attrs)
 		free(dev->attrs);
+	for (i = 0; i < dev->nb_buffer_attrs; i++)
+		free(dev->buffer_attrs[i]);
+	if (dev->nb_buffer_attrs)
+		free(dev->buffer_attrs);
 	for (i = 0; i < dev->nb_debug_attrs; i++)
 		free(dev->debug_attrs[i]);
 	if (dev->nb_debug_attrs)

iio-private.h

@@ -187,6 +187,9 @@ struct iio_device {
 	char **attrs;
 	unsigned int nb_attrs;
 
+	char **buffer_attrs;
+	unsigned int nb_buffer_attrs;
+
 	char **debug_attrs;
 	unsigned int nb_debug_attrs;
 

local.c

@@ -109,6 +109,11 @@ static const char * const device_attrs_blacklist[] = {
 	"uevent",
 };
 
+static const char * const buffer_attrs_reserved[] = {
+	"length",
+	"enable",
+};
+
 static int ioctl_nointr(int fd, unsigned long request, void *data)
 {
 	int ret;
@@ -1488,6 +1493,33 @@ static int detect_and_move_global_attrs(struct iio_device *dev)
 	return 0;
 }
 
+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;
+
+	for (i = 0; i < ARRAY_SIZE(buffer_attrs_reserved); i++)
+		if (!strcmp(buffer_attrs_reserved[i], name))
+			return 0;
+
+	attr = iio_strdup(name);
+	if (!attr)
+		return -ENOMEM;
+
+	attrs = realloc(dev->buffer_attrs, (1 + dev->nb_buffer_attrs) * sizeof(char *));
+	if (!attrs) {
+		free(attr);
+		return -ENOMEM;
+	}
+
+	attrs[dev->nb_buffer_attrs++] = attr;
+	dev->buffer_attrs = attrs;
+	DEBUG("Added buffer attr \'%s\' to device \'%s\'\n", attr, dev->id);
+	return 0;
+}
+
 static int add_attr_or_channel_helper(struct iio_device *dev,
 		const char *path, bool dir_is_scan_elements)
 {
@@ -1583,6 +1615,22 @@ static int add_scan_elements(struct iio_device *dev, const char *devpath)
 	return 0;
 }
 
+static int add_buffer_attributes(struct iio_device *dev, const char *devpath)
+{
+	struct stat st;
+	char buf[1024];
+
+	iio_snprintf(buf, sizeof(buf), "%s/buffer", devpath);
+
+	if (!stat(buf, &st) && S_ISDIR(st.st_mode)) {
+		int ret = foreach_in_dir(dev, buf, false, add_buffer_attr);
+		if (ret < 0)
+			return ret;
+	}
+
+	return 0;
+}
+
 static int create_device(void *d, const char *path)
 {
 	uint32_t *mask = NULL;
@@ -1615,6 +1663,10 @@ static int create_device(void *d, const char *path)
 	if (ret < 0)
 		goto err_free_device;
 
+	ret = add_buffer_attributes(dev, path);
+	if (ret < 0)
+		goto err_free_device;
+
 	ret = add_scan_elements(dev, path);
 	if (ret < 0)
 		goto err_free_scan_elements;