/*
* uvc_v4l2.c -- USB Video Class driver - V4L2 API
*
- * Copyright (C) 2005-2009
- * Laurent Pinchart (laurent.pinchart@skynet.be)
+ * Copyright (C) 2005-2010
+ * Laurent Pinchart (laurent.pinchart@ideasonboard.com)
*
* 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
#include <linux/version.h>
#include <linux/list.h>
#include <linux/module.h>
+#include <linux/slab.h>
#include <linux/usb.h>
#include <linux/videodev2.h>
#include <linux/vmalloc.h>
#include "uvcvideo.h"
/* ------------------------------------------------------------------------
- * V4L2 interface
- */
-
-/*
- * Mapping V4L2 controls to UVC controls can be straighforward if done well.
- * Most of the UVC controls exist in V4L2, and can be mapped directly. Some
- * must be grouped (for instance the Red Balance, Blue Balance and Do White
- * Balance V4L2 controls use the White Balance Component UVC control) or
- * otherwise translated. The approach we take here is to use a translation
- * table for the controls that can be mapped directly, and handle the others
- * manually.
+ * UVC ioctls
*/
-static int uvc_v4l2_query_menu(struct uvc_video_chain *chain,
- struct v4l2_querymenu *query_menu)
+static int uvc_ioctl_ctrl_map(struct uvc_video_chain *chain,
+ struct uvc_xu_control_mapping *xmap, int old)
{
- struct uvc_menu_info *menu_info;
- struct uvc_control_mapping *mapping;
- struct uvc_control *ctrl;
- u32 index = query_menu->index;
- u32 id = query_menu->id;
-
- ctrl = uvc_find_control(chain, query_menu->id, &mapping);
- if (ctrl == NULL || mapping->v4l2_type != V4L2_CTRL_TYPE_MENU)
- return -EINVAL;
+ struct uvc_control_mapping *map;
+ unsigned int size;
+ int ret;
- if (query_menu->index >= mapping->menu_count)
- return -EINVAL;
+ map = kzalloc(sizeof *map, GFP_KERNEL);
+ if (map == NULL)
+ return -ENOMEM;
+
+ map->id = xmap->id;
+ memcpy(map->name, xmap->name, sizeof map->name);
+ memcpy(map->entity, xmap->entity, sizeof map->entity);
+ map->selector = xmap->selector;
+ map->size = xmap->size;
+ map->offset = xmap->offset;
+ map->v4l2_type = xmap->v4l2_type;
+ map->data_type = xmap->data_type;
+
+ switch (xmap->v4l2_type) {
+ case V4L2_CTRL_TYPE_INTEGER:
+ case V4L2_CTRL_TYPE_BOOLEAN:
+ case V4L2_CTRL_TYPE_BUTTON:
+ break;
- memset(query_menu, 0, sizeof(*query_menu));
- query_menu->id = id;
- query_menu->index = index;
+ case V4L2_CTRL_TYPE_MENU:
+ if (old) {
+ uvc_trace(UVC_TRACE_CONTROL, "V4L2_CTRL_TYPE_MENU not "
+ "supported for UVCIOC_CTRL_MAP_OLD.\n");
+ ret = -EINVAL;
+ goto done;
+ }
- menu_info = &mapping->menu_info[query_menu->index];
- strlcpy(query_menu->name, menu_info->name, sizeof query_menu->name);
- return 0;
+ /* Prevent excessive memory consumption, as well as integer
+ * overflows.
+ */
+ if (xmap->menu_count == 0 ||
+ xmap->menu_count > UVC_MAX_CONTROL_MENU_ENTRIES) {
+ ret = -EINVAL;
+ goto done;
+ }
+
+ size = xmap->menu_count * sizeof(*map->menu_info);
+ map->menu_info = kmalloc(size, GFP_KERNEL);
+ if (map->menu_info == NULL) {
+ ret = -ENOMEM;
+ goto done;
+ }
+
+ if (copy_from_user(map->menu_info, xmap->menu_info, size)) {
+ ret = -EFAULT;
+ goto done;
+ }
+
+ map->menu_count = xmap->menu_count;
+ break;
+
+ default:
+ uvc_trace(UVC_TRACE_CONTROL, "Unsupported V4L2 control type "
+ "%u.\n", xmap->v4l2_type);
+ ret = -EINVAL;
+ goto done;
+ }
+
+ ret = uvc_ctrl_add_mapping(chain, map);
+
+done:
+ kfree(map->menu_info);
+ kfree(map);
+
+ return ret;
}
+/* ------------------------------------------------------------------------
+ * V4L2 interface
+ */
+
/*
* Find the frame interval closest to the requested frame interval for the
* given frame format and size. This should be done by the device as part of
* developers test their webcams with the Linux driver as well as with
* the Windows driver).
*/
+ mutex_lock(&stream->mutex);
if (stream->dev->quirks & UVC_QUIRK_PROBE_EXTRAFIELDS)
probe->dwMaxVideoFrameSize =
stream->ctrl.dwMaxVideoFrameSize;
/* Probe the device. */
ret = uvc_probe_video(stream, probe);
+ mutex_unlock(&stream->mutex);
if (ret < 0)
goto done;
static int uvc_v4l2_get_format(struct uvc_streaming *stream,
struct v4l2_format *fmt)
{
- struct uvc_format *format = stream->cur_format;
- struct uvc_frame *frame = stream->cur_frame;
+ struct uvc_format *format;
+ struct uvc_frame *frame;
+ int ret = 0;
if (fmt->type != stream->type)
return -EINVAL;
- if (format == NULL || frame == NULL)
- return -EINVAL;
+ mutex_lock(&stream->mutex);
+ format = stream->cur_format;
+ frame = stream->cur_frame;
+
+ if (format == NULL || frame == NULL) {
+ ret = -EINVAL;
+ goto done;
+ }
fmt->fmt.pix.pixelformat = format->fcc;
fmt->fmt.pix.width = frame->wWidth;
fmt->fmt.pix.colorspace = format->colorspace;
fmt->fmt.pix.priv = 0;
- return 0;
+done:
+ mutex_unlock(&stream->mutex);
+ return ret;
}
static int uvc_v4l2_set_format(struct uvc_streaming *stream,
return -EINVAL;
}
- if (uvc_queue_allocated(&stream->queue)) {
- printk("uvc_queue_allocated failed\n");
- return -EBUSY;
-
- }
-
ret = uvc_v4l2_try_format(stream, fmt, &probe, &format, &frame);
if (ret < 0)
return ret;
+ mutex_lock(&stream->mutex);
+
+ if (uvc_queue_allocated(&stream->queue)) {
+ printk("uvc_queue_allocated failed\n");
+ ret = -EBUSY;
+ goto done;
+ }
+
memcpy(&stream->ctrl, &probe, sizeof probe);
stream->cur_format = format;
stream->cur_frame = frame;
- return 0;
+done:
+ mutex_unlock(&stream->mutex);
+ return ret;
}
static int uvc_v4l2_get_streamparm(struct uvc_streaming *stream,
if (parm->type != stream->type)
return -EINVAL;
+ mutex_lock(&stream->mutex);
numerator = stream->ctrl.dwFrameInterval;
+ mutex_unlock(&stream->mutex);
+
denominator = 10000000;
uvc_simplify_fraction(&numerator, &denominator, 8, 333);
static int uvc_v4l2_set_streamparm(struct uvc_streaming *stream,
struct v4l2_streamparm *parm)
{
- struct uvc_frame *frame = stream->cur_frame;
struct uvc_streaming_control probe;
struct v4l2_fract timeperframe;
uint32_t interval;
if (parm->type != stream->type)
return -EINVAL;
- if (uvc_queue_streaming(&stream->queue))
- return -EBUSY;
-
if (parm->type == V4L2_BUF_TYPE_VIDEO_CAPTURE)
timeperframe = parm->parm.capture.timeperframe;
else
timeperframe = parm->parm.output.timeperframe;
- memcpy(&probe, &stream->ctrl, sizeof probe);
interval = uvc_fraction_to_interval(timeperframe.numerator,
timeperframe.denominator);
-
uvc_trace(UVC_TRACE_FORMAT, "Setting frame interval to %u/%u (%u).\n",
timeperframe.numerator, timeperframe.denominator, interval);
- probe.dwFrameInterval = uvc_try_frame_interval(frame, interval);
+
+ mutex_lock(&stream->mutex);
+
+ if (uvc_queue_streaming(&stream->queue)) {
+ mutex_unlock(&stream->mutex);
+ return -EBUSY;
+ }
+
+ memcpy(&probe, &stream->ctrl, sizeof probe);
+ probe.dwFrameInterval =
+ uvc_try_frame_interval(stream->cur_frame, interval);
/* Probe the device with the new settings. */
ret = uvc_probe_video(stream, &probe);
- if (ret < 0)
+ if (ret < 0) {
+ mutex_unlock(&stream->mutex);
return ret;
+ }
memcpy(&stream->ctrl, &probe, sizeof probe);
+ mutex_unlock(&stream->mutex);
/* Return the actual frame period. */
timeperframe.numerator = probe.dwFrameInterval;
* unprivileged state. Only a single instance can be in a privileged state at
* a given time. Trying to perform an operation that requires privileges will
* automatically acquire the required privileges if possible, or return -EBUSY
- * otherwise. Privileges are dismissed when closing the instance.
+ * otherwise. Privileges are dismissed when closing the instance or when
+ * freeing the video buffers using VIDIOC_REQBUFS.
*
* Operations that require privileges are:
*
* - VIDIOC_S_INPUT
* - VIDIOC_S_PARM
* - VIDIOC_S_FMT
- * - VIDIOC_TRY_FMT
* - VIDIOC_REQBUFS
*/
static int uvc_acquire_privileges(struct uvc_fh *handle)
{
- int ret = 0;
-
/* Always succeed if the handle is already privileged. */
if (handle->state == UVC_HANDLE_ACTIVE)
return 0;
/* Check if the device already has a privileged handle. */
- mutex_lock(&uvc_driver.open_mutex);
if (atomic_inc_return(&handle->stream->active) != 1) {
atomic_dec(&handle->stream->active);
- ret = -EBUSY;
- goto done;
+ return -EBUSY;
}
handle->state = UVC_HANDLE_ACTIVE;
-
-done:
- mutex_unlock(&uvc_driver.open_mutex);
- return ret;
+ return 0;
}
static void uvc_dismiss_privileges(struct uvc_fh *handle)
int ret = 0;
uvc_trace(UVC_TRACE_CALLS, "uvc_v4l2_open\n");
- mutex_lock(&uvc_driver.open_mutex);
stream = video_drvdata(file);
- if (stream->dev->state & UVC_DEV_DISCONNECTED) {
- ret = -ENODEV;
- goto done;
- }
+ if (stream->dev->state & UVC_DEV_DISCONNECTED)
+ return -ENODEV;
ret = usb_autopm_get_interface(stream->dev->intf);
if (ret < 0)
- goto done;
+ return ret;
/* Create the device handle. */
handle = kzalloc(sizeof *handle, GFP_KERNEL);
if (handle == NULL) {
usb_autopm_put_interface(stream->dev->intf);
- ret = -ENOMEM;
- goto done;
+ return -ENOMEM;
}
if (atomic_inc_return(&stream->dev->users) == 1) {
usb_autopm_put_interface(stream->dev->intf);
atomic_dec(&stream->dev->users);
kfree(handle);
- goto done;
+ return ret;
}
}
handle->state = UVC_HANDLE_PASSIVE;
file->private_data = handle;
- kref_get(&stream->dev->kref);
-
-done:
- mutex_unlock(&uvc_driver.open_mutex);
- return ret;
+ return 0;
}
static int uvc_v4l2_release(struct file *file)
{
- struct uvc_fh *handle = (struct uvc_fh *)file->private_data;
+ struct uvc_fh *handle = file->private_data;
struct uvc_streaming *stream = handle->stream;
uvc_trace(UVC_TRACE_CALLS, "uvc_v4l2_release\n");
if (uvc_has_privileges(handle)) {
uvc_video_enable(stream, 0);
- mutex_lock(&stream->queue.mutex);
if (uvc_free_buffers(&stream->queue) < 0)
uvc_printk(KERN_ERR, "uvc_v4l2_release: Unable to "
"free buffers.\n");
- mutex_unlock(&stream->queue.mutex);
}
/* Release the file handle. */
uvc_status_stop(stream->dev);
usb_autopm_put_interface(stream->dev->intf);
- kref_put(&stream->dev->kref, uvc_delete);
return 0;
}
+static void uvc_v4l2_ioctl_warn(void)
+{
+ static int warned;
+
+ if (warned)
+ return;
+
+ uvc_printk(KERN_INFO, "Deprecated UVCIOC_CTRL_{ADD,MAP_OLD,GET,SET} "
+ "ioctls will be removed in 2.6.42.\n");
+ uvc_printk(KERN_INFO, "See http://www.ideasonboard.org/uvc/upgrade/ "
+ "for upgrade instructions.\n");
+ warned = 1;
+}
+
static long uvc_v4l2_do_ioctl(struct file *file, unsigned int cmd, void *arg)
{
struct video_device *vdev = video_devdata(file);
- struct uvc_fh *handle = (struct uvc_fh *)file->private_data;
+ struct uvc_fh *handle = file->private_data;
struct uvc_video_chain *chain = handle->chain;
struct uvc_streaming *stream = handle->stream;
long ret = 0;
xctrl.id = ctrl->id;
xctrl.value = ctrl->value;
- uvc_ctrl_begin(chain);
+ ret = uvc_ctrl_begin(chain);
if (ret < 0)
return ret;
return ret;
}
ret = uvc_ctrl_commit(chain);
+ if (ret == 0)
+ ctrl->value = xctrl.value;
break;
}
case VIDIOC_QUERYMENU:
- return uvc_v4l2_query_menu(chain, arg);
+ return uvc_query_v4l2_menu(chain, arg);
case VIDIOC_G_EXT_CTRLS:
{
(chain->dev->quirks & UVC_QUIRK_IGNORE_SELECTOR_UNIT)) {
if (index != 0)
return -EINVAL;
- iterm = list_first_entry(&chain->iterms,
- struct uvc_entity, chain);
+ list_for_each_entry(iterm, &chain->entities, chain) {
+ if (UVC_ENTITY_IS_ITERM(iterm))
+ break;
+ }
pin = iterm->id;
- } else if (pin < selector->selector.bNrInPins) {
- pin = selector->selector.baSourceID[index];
- list_for_each_entry(iterm, chain->iterms.next, chain) {
+ } else if (index < selector->bNrInPins) {
+ pin = selector->baSourceID[index];
+ list_for_each_entry(iterm, &chain->entities, chain) {
+ if (!UVC_ENTITY_IS_ITERM(iterm))
+ continue;
if (iterm->id == pin)
break;
}
break;
}
- if (input == 0 || input > chain->selector->selector.bNrInPins)
+ if (input == 0 || input > chain->selector->bNrInPins)
return -EINVAL;
return uvc_query_ctrl(chain->dev, UVC_SET_CUR,
{
struct uvc_streaming_control probe;
- if ((ret = uvc_acquire_privileges(handle)) < 0)
- return ret;
-
return uvc_v4l2_try_format(stream, arg, &probe, NULL, NULL);
}
case VIDIOC_CROPCAP:
{
struct v4l2_cropcap *ccap = arg;
- struct uvc_frame *frame = stream->cur_frame;
if (ccap->type != stream->type)
return -EINVAL;
ccap->bounds.left = 0;
ccap->bounds.top = 0;
- ccap->bounds.width = frame->wWidth;
- ccap->bounds.height = frame->wHeight;
+
+ mutex_lock(&stream->mutex);
+ ccap->bounds.width = stream->cur_frame->wWidth;
+ ccap->bounds.height = stream->cur_frame->wHeight;
+ mutex_unlock(&stream->mutex);
ccap->defrect = ccap->bounds;
case VIDIOC_REQBUFS:
{
struct v4l2_requestbuffers *rb = arg;
- unsigned int bufsize =
- stream->ctrl.dwMaxVideoFrameSize;
if (rb->type != stream->type ||
rb->memory != V4L2_MEMORY_MMAP)
if ((ret = uvc_acquire_privileges(handle)) < 0)
return ret;
- ret = uvc_alloc_buffers(&stream->queue, rb->count, bufsize);
+ mutex_lock(&stream->mutex);
+ ret = uvc_alloc_buffers(&stream->queue, rb->count,
+ stream->ctrl.dwMaxVideoFrameSize);
+ mutex_unlock(&stream->mutex);
if (ret < 0)
return ret;
+ if (ret == 0)
+ uvc_dismiss_privileges(handle);
+
rb->count = ret;
ret = 0;
break;
if (!uvc_has_privileges(handle))
return -EBUSY;
+ mutex_lock(&stream->mutex);
ret = uvc_video_enable(stream, 1);
+ mutex_unlock(&stream->mutex);
if (ret < 0)
return ret;
break;
uvc_trace(UVC_TRACE_IOCTL, "Unsupported ioctl 0x%08x\n", cmd);
return -EINVAL;
- /* Dynamic controls. */
- case UVCIOC_CTRL_ADD:
- {
- struct uvc_xu_control_info *xinfo = arg;
- struct uvc_control_info *info;
-
- if (!capable(CAP_SYS_ADMIN))
- return -EPERM;
-
- info = kzalloc(sizeof *info, GFP_KERNEL);
- if (info == NULL)
- return -ENOMEM;
-
- memcpy(info->entity, xinfo->entity, sizeof info->entity);
- info->index = xinfo->index;
- info->selector = xinfo->selector;
- info->size = xinfo->size;
- info->flags = xinfo->flags;
-
- info->flags |= UVC_CONTROL_GET_MIN | UVC_CONTROL_GET_MAX |
- UVC_CONTROL_GET_RES | UVC_CONTROL_GET_DEF;
-
- ret = uvc_ctrl_add_info(info);
- if (ret < 0)
- kfree(info);
- break;
- }
+ /* Dynamic controls. UVCIOC_CTRL_ADD, UVCIOC_CTRL_MAP_OLD,
+ * UVCIOC_CTRL_GET and UVCIOC_CTRL_SET are deprecated and scheduled for
+ * removal in 2.6.42.
+ */
+ case __UVCIOC_CTRL_ADD:
+ uvc_v4l2_ioctl_warn();
+ return -EEXIST;
+ case __UVCIOC_CTRL_MAP_OLD:
+ uvc_v4l2_ioctl_warn();
+ case __UVCIOC_CTRL_MAP:
case UVCIOC_CTRL_MAP:
+ return uvc_ioctl_ctrl_map(chain, arg,
+ cmd == __UVCIOC_CTRL_MAP_OLD);
+
+ case __UVCIOC_CTRL_GET:
+ case __UVCIOC_CTRL_SET:
{
- struct uvc_xu_control_mapping *xmap = arg;
- struct uvc_control_mapping *map;
-
- if (!capable(CAP_SYS_ADMIN))
- return -EPERM;
-
- map = kzalloc(sizeof *map, GFP_KERNEL);
- if (map == NULL)
- return -ENOMEM;
-
- map->id = xmap->id;
- memcpy(map->name, xmap->name, sizeof map->name);
- memcpy(map->entity, xmap->entity, sizeof map->entity);
- map->selector = xmap->selector;
- map->size = xmap->size;
- map->offset = xmap->offset;
- map->v4l2_type = xmap->v4l2_type;
- map->data_type = xmap->data_type;
-
- ret = uvc_ctrl_add_mapping(map);
- if (ret < 0)
- kfree(map);
- break;
+ struct uvc_xu_control *xctrl = arg;
+ struct uvc_xu_control_query xqry = {
+ .unit = xctrl->unit,
+ .selector = xctrl->selector,
+ .query = cmd == __UVCIOC_CTRL_GET
+ ? UVC_GET_CUR : UVC_SET_CUR,
+ .size = xctrl->size,
+ .data = xctrl->data,
+ };
+
+ uvc_v4l2_ioctl_warn();
+ return uvc_xu_ctrl_query(chain, &xqry);
}
- case UVCIOC_CTRL_GET:
- return uvc_xu_ctrl_query(chain, arg, 0);
-
- case UVCIOC_CTRL_SET:
- return uvc_xu_ctrl_query(chain, arg, 1);
+ case UVCIOC_CTRL_QUERY:
+ return uvc_xu_ctrl_query(chain, arg);
default:
- if ((ret = v4l_compat_translate_ioctl(file, cmd, arg,
- uvc_v4l2_do_ioctl)) == -ENOIOCTLCMD)
- uvc_trace(UVC_TRACE_IOCTL, "Unknown ioctl 0x%08x\n",
- cmd);
- return ret;
+ uvc_trace(UVC_TRACE_IOCTL, "Unknown ioctl 0x%08x\n", cmd);
+ return -EINVAL;
}
return ret;
size_t count, loff_t *ppos)
{
uvc_trace(UVC_TRACE_CALLS, "uvc_v4l2_read: not implemented.\n");
- return -ENODEV;
-}
-
-/*
- * VMA operations.
- */
-static void uvc_vm_open(struct vm_area_struct *vma)
-{
- struct uvc_buffer *buffer = vma->vm_private_data;
- buffer->vma_use_count++;
-}
-
-static void uvc_vm_close(struct vm_area_struct *vma)
-{
- struct uvc_buffer *buffer = vma->vm_private_data;
- buffer->vma_use_count--;
+ return -EINVAL;
}
-static const struct vm_operations_struct uvc_vm_ops = {
- .open = uvc_vm_open,
- .close = uvc_vm_close,
-};
-
static int uvc_v4l2_mmap(struct file *file, struct vm_area_struct *vma)
{
- struct uvc_fh *handle = (struct uvc_fh *)file->private_data;
+ struct uvc_fh *handle = file->private_data;
struct uvc_streaming *stream = handle->stream;
- struct uvc_video_queue *queue = &stream->queue;
- struct uvc_buffer *uninitialized_var(buffer);
- struct page *page;
- unsigned long addr, start, size;
- unsigned int i;
- int ret = 0;
uvc_trace(UVC_TRACE_CALLS, "uvc_v4l2_mmap\n");
- start = vma->vm_start;
- size = vma->vm_end - vma->vm_start;
-
- mutex_lock(&queue->mutex);
-
- for (i = 0; i < queue->count; ++i) {
- buffer = &queue->buffer[i];
- if ((buffer->buf.m.offset >> PAGE_SHIFT) == vma->vm_pgoff)
- break;
- }
-
- if (i == queue->count || size != queue->buf_size) {
- ret = -EINVAL;
- goto done;
- }
-
- /*
- * VM_IO marks the area as being an mmaped region for I/O to a
- * device. It also prevents the region from being core dumped.
- */
- vma->vm_flags |= VM_IO;
-
- addr = (unsigned long)queue->mem + buffer->buf.m.offset;
- while (size > 0) {
- page = vmalloc_to_page((void *)addr);
- if ((ret = vm_insert_page(vma, start, page)) < 0)
- goto done;
-
- start += PAGE_SIZE;
- addr += PAGE_SIZE;
- size -= PAGE_SIZE;
- }
-
- vma->vm_ops = &uvc_vm_ops;
- vma->vm_private_data = buffer;
- uvc_vm_open(vma);
-
-done:
- mutex_unlock(&queue->mutex);
- return ret;
+ return uvc_queue_mmap(&stream->queue, vma);
}
static unsigned int uvc_v4l2_poll(struct file *file, poll_table *wait)
{
- struct uvc_fh *handle = (struct uvc_fh *)file->private_data;
+ struct uvc_fh *handle = file->private_data;
struct uvc_streaming *stream = handle->stream;
uvc_trace(UVC_TRACE_CALLS, "uvc_v4l2_poll\n");
return uvc_queue_poll(&stream->queue, file, wait);
}
+#ifndef CONFIG_MMU
+static unsigned long uvc_v4l2_get_unmapped_area(struct file *file,
+ unsigned long addr, unsigned long len, unsigned long pgoff,
+ unsigned long flags)
+{
+ struct uvc_fh *handle = file->private_data;
+ struct uvc_streaming *stream = handle->stream;
+
+ uvc_trace(UVC_TRACE_CALLS, "uvc_v4l2_get_unmapped_area\n");
+
+ return uvc_queue_get_unmapped_area(&stream->queue, pgoff);
+}
+#endif
+
const struct v4l2_file_operations uvc_fops = {
.owner = THIS_MODULE,
.open = uvc_v4l2_open,
.release = uvc_v4l2_release,
- .ioctl = uvc_v4l2_ioctl,
+ .unlocked_ioctl = uvc_v4l2_ioctl,
.read = uvc_v4l2_read,
.mmap = uvc_v4l2_mmap,
.poll = uvc_v4l2_poll,
+#ifndef CONFIG_MMU
+ .get_unmapped_area = uvc_v4l2_get_unmapped_area,
+#endif
};
projects / firefly-linux-kernel-4.4.55.git / blobdiff