Moving v4l1 ioctls from kernel to libv4l1

Hi All,
I have been working with Hans for moving the v4l1 ioctls from the kernel to libv4l1.
It would be best to work on one ioctl at a time.
The enclosed patch attempts to implement VIDIOCGCAP in the libv4l1.

Note: Hans is working with Bill, asking for permission to re-use the v4l1-compat.c code under the LGPL

lib/libv4l1/libv4l1.c +33 -0

index eae3b43..8571651 100644
@@ -61,6 +61,10 @@
  #define V4L1_PIX_FMT_TOUCHED    0x04
  #define V4L1_PIX_SIZE_TOUCHED   0x08
 
+#ifndef min
+	#define min( a, b ) ( ((a)<  (b)) ? (a) : (b) )
+#endif
+
  static pthread_mutex_t v4l1_open_mutex = PTHREAD_MUTEX_INITIALIZER;
  static struct v4l1_dev_info devices[V4L1_MAX_DEVICES] = {
  	{ .fd = -1 },

@@ -130,6 +134,45 @@ static unsigned int pixelformat_to_palette(unsigned
 int pixelformat)
  	return 0;
  }
 
+static int count_inputs(int fd)
+{
+	struct v4l2_input input2;
+	int i;
+	for (i = 0;; i++) {
+		memset(&input2, 0, sizeof(input2));
+		input2.index = i;
+		if (0 != SYS_IOCTL(fd, VIDIOC_ENUMINPUT,&input2))
+			break;
+		}
+	return i;
+}
+
+static int check_size(int fd,int *maxw,int *maxh)
+{
+	struct v4l2_fmtdesc desc2;
+	struct v4l2_format fmt2;
+
+	memset(&desc2, 0, sizeof(desc2));
+	memset(&fmt2, 0, sizeof(fmt2));
+
+	desc2.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+	if (0 != SYS_IOCTL(fd, VIDIOC_ENUM_FMT,&desc2))
+		goto done;
+
+	fmt2.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+	fmt2.fmt.pix.width = 10000;
+	fmt2.fmt.pix.height = 10000;
+	fmt2.fmt.pix.pixelformat = desc2.pixelformat;

lib/libv4l1/libv4l1.c +22 -0

+		err = SYS_IOCTL(fd, VIDIOC_QUERYCAP,cap2);
+		if (err<  0)
+			goto done;
+
+		if (cap2->capabilities&  V4L2_CAP_VIDEO_OVERLAY) {
+			err = SYS_IOCTL(fd, VIDIOC_G_FBUF,&fbuf);
+			if (err<  0) {
+				memset(&fbuf, 0, sizeof(fbuf));
+			}
+			err = 0;
+		}
+		
+		memcpy(cap->name,  cap2->card,
 min(sizeof(cap->name),sizeof(cap2->card)) );
+		
+		cap->name[sizeof(cap->name) -1 ] = 0;
+	
+		if (cap2->capabilities&  V4L2_CAP_VIDEO_CAPTURE)
+			cap->type |= VID_TYPE_CAPTURE;
+		if (cap2->capabilities&  V4L2_CAP_TUNER)
+			cap->type |= VID_TYPE_TUNER;
+		if (cap2->capabilities&  V4L2_CAP_VBI_CAPTURE)
+			cap->type |= VID_TYPE_TELETEXT;

lib/libv4l1/libv4l1.c +1 -0

+
 
  		/* override kernel v4l1 compat min / max size with our own more

accurate values */

Hi Huzaifa,

First of all many thanks for working on this!

Comments inline.

Quoted 60 lines · Huzaifa Sidhpurwala

Hi All,
I have been working with Hans for moving the v4l1 ioctls from the kernel to libv4l1.
It would be best to work on one ioctl at a time.
The enclosed patch attempts to implement VIDIOCGCAP in the libv4l1.

Note: Hans is working with Bill, asking for permission to re-use the v4l1-compat.c code under the LGPL

lib/libv4l1/libv4l1.c +33 -0

index eae3b43..8571651 100644
@@ -61,6 +61,10 @@
  #define V4L1_PIX_FMT_TOUCHED    0x04
  #define V4L1_PIX_SIZE_TOUCHED   0x08
 
+#ifndef min
+    #define min( a, b ) ( ((a)<  (b)) ? (a) : (b) )
+#endif
+
  static pthread_mutex_t v4l1_open_mutex = PTHREAD_MUTEX_INITIALIZER;
  static struct v4l1_dev_info devices[V4L1_MAX_DEVICES] = {
      { .fd = -1 },

@@ -130,6 +134,45 @@ static unsigned int pixelformat_to_palette(unsigned
 int pixelformat)
      return 0;
  }
 
+static int count_inputs(int fd)
+{
+    struct v4l2_input input2;
+    int i;
+    for (i = 0;; i++) {
+        memset(&input2, 0, sizeof(input2));
+        input2.index = i;
+        if (0 != SYS_IOCTL(fd, VIDIOC_ENUMINPUT,&input2))
+            break;
+        }
+    return i;
+}
+
+static int check_size(int fd,int *maxw,int *maxh)
+{
+    struct v4l2_fmtdesc desc2;
+    struct v4l2_format fmt2;
+
+    memset(&desc2, 0, sizeof(desc2));
+    memset(&fmt2, 0, sizeof(fmt2));
+
+    desc2.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+    if (0 != SYS_IOCTL(fd, VIDIOC_ENUM_FMT,&desc2))
+        goto done;
+
+    fmt2.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+    fmt2.fmt.pix.width = 10000;
+    fmt2.fmt.pix.height = 10000;
+    fmt2.fmt.pix.pixelformat = desc2.pixelformat;

lib/libv4l1/libv4l1.c static unsigned int pixelformat_to_palette(unsigned · line 176

Quoted 10 lines

lib/libv4l1/libv4l1.c +10 -0

+    if (0 != SYS_IOCTL(fd, VIDIOC_TRY_FMT,&fmt2))
+        goto done;
+
+    *maxw = fmt2.fmt.pix.width;
+    *maxh = fmt2.fmt.pix.height;
+
+    done:
+    return 0;
+}
+

We don't need this function, see below.

lib/libv4l1/libv4l1.c int v4l1_ioctl(int fd, unsigned long int request, · line 541

Quoted 12 lines

lib/libv4l1/libv4l1.c +0 -0

  static int v4l1_set_format(int index, unsigned int width,
          unsigned int height, int v4l1_pal, int width_height_may_differ)

  {

lib/libv4l1/libv4l1.c +3 -1

@@ -492,7 +535,54 @@ int v4l1_ioctl(int fd, unsigned long int request,
 ...)
      case VIDIOCGCAP: {
          struct video_capability *cap = arg;
 
-        result = SYS_IOCTL(fd, request, arg);
+        long err;
+        struct v4l2_framebuffer fbuf;
+        struct v4l2_capability *cap2;

The kernel mallocs struct v4l2_capability because the kernel stack is severely limited, no need to do that in userspace, just put the entire struct on the stack.

lib/libv4l1/libv4l1.c int v4l1_ioctl(int fd, unsigned long int request, · line 550

Quoted 9 lines

lib/libv4l1/libv4l1.c +9 -0

+
+        cap2 = malloc (sizeof(*cap2));
+        if (!cap2) {
+            return -ENOMEM;
+        }
+
+        memset(cap,0,sizeof(*cap));
+        memset(&fbuf, 0, sizeof(fbuf));
+

You can get the memset effect, by initalizing the first field of the struct to 0, the compiler will then 0 out the rest:

        struct v4l2_framebuffer fbuf = { 0, };
        struct v4l2_capability cap2 =  { 0, };

Quoted 23 lines

lib/libv4l1/libv4l1.c +22 -0

+        err = SYS_IOCTL(fd, VIDIOC_QUERYCAP,cap2);
+        if (err<  0)
+            goto done;
+
+        if (cap2->capabilities&  V4L2_CAP_VIDEO_OVERLAY) {
+            err = SYS_IOCTL(fd, VIDIOC_G_FBUF,&fbuf);
+            if (err<  0) {
+                memset(&fbuf, 0, sizeof(fbuf));
+            }
+            err = 0;
+        }
+       
+        memcpy(cap->name,  cap2->card,
 min(sizeof(cap->name),sizeof(cap2->card)) );
+       
+        cap->name[sizeof(cap->name) -1 ] = 0;
+   
+        if (cap2->capabilities&  V4L2_CAP_VIDEO_CAPTURE)
+            cap->type |= VID_TYPE_CAPTURE;
+        if (cap2->capabilities&  V4L2_CAP_TUNER)
+            cap->type |= VID_TYPE_TUNER;
+        if (cap2->capabilities&  V4L2_CAP_VBI_CAPTURE)
+            cap->type |= VID_TYPE_TELETEXT;

lib/libv4l1/libv4l1.c int v4l1_ioctl(int fd, unsigned long int request, · line 583

Quoted 10 lines

lib/libv4l1/libv4l1.c +10 -0

+        if (cap2->capabilities&  V4L2_CAP_VIDEO_OVERLAY)
+            cap->type |= VID_TYPE_OVERLAY;
+        if (fbuf.capability&  V4L2_FBUF_CAP_LIST_CLIPPING)
+            cap->type |= VID_TYPE_CLIPPING;
+
+        cap->channels = count_inputs(fd);
+
+        check_size(fd,
+            &cap->maxwidth,&cap->maxheight);
+                   

No need to check size here, as we override that below, so this line can be dropped.

lib/libv4l1/libv4l1.c int v4l1_ioctl(int fd, unsigned long int request, · line 586

Quoted 3 lines

lib/libv4l1/libv4l1.c +3 -0

+       
+    /*    result = SYS_IOCTL(fd, request, arg);*/
+

This can be dropped too.

Quoted 4 lines

lib/libv4l1/libv4l1.c +1 -0

+
 

/* override kernel v4l1 compat min / max size with our own more
accurate values */

And the override comment can be dropped to, as we no longer will be suing the v4l1 compat code check_size stuff.

lib/libv4l1/libv4l1.c int v4l1_ioctl(int fd, unsigned long int request, · line 598

Quoted 11 lines

lib/libv4l1/libv4l1.c +4 -1

@@ -500,7 +590,10 @@ int v4l1_ioctl(int fd, unsigned long int request,
 ...)
          cap->minheight = devices[index].min_height;
          cap->maxwidth  = devices[index].max_width;
          cap->maxheight = devices[index].max_height;
-        break;
+
+        done:
+            free(cap2);
+            break;
      }

No need to do this either when we drop the malloc.

Quoted 1 line

Quoted 2 lines

      case VIDIOCSPICT: {

Thanks & Regards,

Hans

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

Thanks a lot for the review, here is the improved version.

lib/libv4l1/libv4l1.c +18 -1

index eae3b43..9ef9980 100644
- --- a/lib/libv4l1/libv4l1.c
+++ b/lib/libv4l1/libv4l1.c

@@ -61,6 +61,10 @@
  #define V4L1_PIX_FMT_TOUCHED    0x04
  #define V4L1_PIX_SIZE_TOUCHED   0x08
 
+#ifndef min
+    #define min( a, b ) ( ((a)<  (b)) ? (a) : (b) )
+#endif
+
  static pthread_mutex_t v4l1_open_mutex = PTHREAD_MUTEX_INITIALIZER;
  static struct v4l1_dev_info devices[V4L1_MAX_DEVICES] = {
  	{ .fd = -1 },

@@ -130,6 +134,19 @@ static unsigned int pixelformat_to_palette(unsigned
 int pixelformat)
  	return 0;
  }
 
+static int count_inputs(int fd)
+{
+	struct v4l2_input input2;
+	int i;
+	for (i = 0;; i++) {
+		memset(&input2, 0, sizeof(input2));
+		input2.index = i;
+		if (0 != SYS_IOCTL(fd, VIDIOC_ENUMINPUT,&input2))
+			break;
+		}
+	return i;
+}
+
  static int v4l1_set_format(int index, unsigned int width,
  		unsigned int height, int v4l1_pal, int width_height_may_differ)

  {

lib/libv4l1/libv4l1.c +33 -3

@@ -491,16 +508,46 @@ int v4l1_ioctl(int fd, unsigned long int request, ...)
  	switch (request) {
  	case VIDIOCGCAP: {
  		struct video_capability *cap = arg;
+		
+		struct v4l2_framebuffer fbuf = { 0, };
+		struct v4l2_capability cap2 =  { 0, };
 
- -		result = SYS_IOCTL(fd, request, arg);
+		result = SYS_IOCTL(fd, VIDIOC_QUERYCAP,&cap2);
+		if (result<  0)
+			break;
+
+		if (cap2.capabilities&  V4L2_CAP_VIDEO_OVERLAY) {
+			result = SYS_IOCTL(fd, VIDIOC_G_FBUF,&fbuf);
+			if (result<  0) {
+				memset(&fbuf, 0, sizeof(fbuf));
+			}
+			result = 0;
+		}
+		
+		memcpy(cap->name,  cap2.card, min(sizeof(cap->name),sizeof(cap2.card)) );
+		
+		cap->name[sizeof(cap->name) -1 ] = 0;
+	
+		if (cap2.capabilities&  V4L2_CAP_VIDEO_CAPTURE)
+			cap->type |= VID_TYPE_CAPTURE;
+		if (cap2.capabilities&  V4L2_CAP_TUNER)
+			cap->type |= VID_TYPE_TUNER;
+		if (cap2.capabilities&  V4L2_CAP_VBI_CAPTURE)
+			cap->type |= VID_TYPE_TELETEXT;
+		if (cap2.capabilities&  V4L2_CAP_VIDEO_OVERLAY)
+			cap->type |= VID_TYPE_OVERLAY;
+		if (fbuf.capability&  V4L2_FBUF_CAP_LIST_CLIPPING)
+			cap->type |= VID_TYPE_CLIPPING;
+
+		cap->channels = count_inputs(fd);
 
- -		/* override kernel v4l1 compat min / max size with our own more
- -		   accurate values */
  		cap->minwidth  = devices[index].min_width;
  		cap->minheight = devices[index].min_height;
  		cap->maxwidth  = devices[index].max_width;
  		cap->maxheight = devices[index].max_height;
+
  		break;
+
  	}
 
  	case VIDIOCSPICT: {

Quoted 179 lines · Hans de Goede

Hi Huzaifa,

First of all many thanks for working on this!

Comments inline.

Quoted 60 lines · Huzaifa Sidhpurwala

Hi All,
I have been working with Hans for moving the v4l1 ioctls from the kernel to libv4l1.
It would be best to work on one ioctl at a time.
The enclosed patch attempts to implement VIDIOCGCAP in the libv4l1.

Note: Hans is working with Bill, asking for permission to re-use the v4l1-compat.c code under the LGPL

lib/libv4l1/libv4l1.c +33 -0

index eae3b43..8571651 100644
@@ -61,6 +61,10 @@
   #define V4L1_PIX_FMT_TOUCHED    0x04
   #define V4L1_PIX_SIZE_TOUCHED   0x08
 
+#ifndef min
+    #define min( a, b ) ( ((a)<   (b)) ? (a) : (b) )
+#endif
+
   static pthread_mutex_t v4l1_open_mutex = PTHREAD_MUTEX_INITIALIZER;
   static struct v4l1_dev_info devices[V4L1_MAX_DEVICES] = {
       { .fd = -1 },

@@ -130,6 +134,45 @@ static unsigned int pixelformat_to_palette(unsigned
 int pixelformat)
       return 0;
   }
 
+static int count_inputs(int fd)
+{
+    struct v4l2_input input2;
+    int i;
+    for (i = 0;; i++) {
+        memset(&input2, 0, sizeof(input2));
+        input2.index = i;
+        if (0 != SYS_IOCTL(fd, VIDIOC_ENUMINPUT,&input2))
+            break;
+        }
+    return i;
+}
+
+static int check_size(int fd,int *maxw,int *maxh)
+{
+    struct v4l2_fmtdesc desc2;
+    struct v4l2_format fmt2;
+
+    memset(&desc2, 0, sizeof(desc2));
+    memset(&fmt2, 0, sizeof(fmt2));
+
+    desc2.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+    if (0 != SYS_IOCTL(fd, VIDIOC_ENUM_FMT,&desc2))
+        goto done;
+
+    fmt2.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+    fmt2.fmt.pix.width = 10000;
+    fmt2.fmt.pix.height = 10000;
+    fmt2.fmt.pix.pixelformat = desc2.pixelformat;

lib/libv4l1/libv4l1.c static unsigned int pixelformat_to_palette(unsigned · line 176

Quoted 10 lines

lib/libv4l1/libv4l1.c +10 -0

+    if (0 != SYS_IOCTL(fd, VIDIOC_TRY_FMT,&fmt2))
+        goto done;
+
+    *maxw = fmt2.fmt.pix.width;
+    *maxh = fmt2.fmt.pix.height;
+
+    done:
+    return 0;
+}
+

We don't need this function, see below.

lib/libv4l1/libv4l1.c int v4l1_ioctl(int fd, unsigned long int request, · line 541

Quoted 12 lines

lib/libv4l1/libv4l1.c +0 -0

   static int v4l1_set_format(int index, unsigned int width,
           unsigned int height, int v4l1_pal, int width_height_may_differ)

   {

lib/libv4l1/libv4l1.c +3 -1

@@ -492,7 +535,54 @@ int v4l1_ioctl(int fd, unsigned long int request,
 ...)
       case VIDIOCGCAP: {
           struct video_capability *cap = arg;
 
-        result = SYS_IOCTL(fd, request, arg);
+        long err;
+        struct v4l2_framebuffer fbuf;
+        struct v4l2_capability *cap2;

The kernel mallocs struct v4l2_capability because the kernel stack is severely limited, no need to do that in userspace, just put the entire struct on the stack.

lib/libv4l1/libv4l1.c int v4l1_ioctl(int fd, unsigned long int request, · line 550

Quoted 9 lines

lib/libv4l1/libv4l1.c +9 -0

+
+        cap2 = malloc (sizeof(*cap2));
+        if (!cap2) {
+            return -ENOMEM;
+        }
+
+        memset(cap,0,sizeof(*cap));
+        memset(&fbuf, 0, sizeof(fbuf));
+

You can get the memset effect, by initalizing the first field of the struct to 0, the compiler will then 0 out the rest:

         struct v4l2_framebuffer fbuf = { 0, };
         struct v4l2_capability cap2 =  { 0, };

Quoted 23 lines

lib/libv4l1/libv4l1.c +22 -0

+        err = SYS_IOCTL(fd, VIDIOC_QUERYCAP,cap2);
+        if (err<   0)
+            goto done;
+
+        if (cap2->capabilities&   V4L2_CAP_VIDEO_OVERLAY) {
+            err = SYS_IOCTL(fd, VIDIOC_G_FBUF,&fbuf);
+            if (err<   0) {
+                memset(&fbuf, 0, sizeof(fbuf));
+            }
+            err = 0;
+        }
+
+        memcpy(cap->name,  cap2->card,
 min(sizeof(cap->name),sizeof(cap2->card)) );
+
+        cap->name[sizeof(cap->name) -1 ] = 0;
+
+        if (cap2->capabilities&   V4L2_CAP_VIDEO_CAPTURE)
+            cap->type |= VID_TYPE_CAPTURE;
+        if (cap2->capabilities&   V4L2_CAP_TUNER)
+            cap->type |= VID_TYPE_TUNER;
+        if (cap2->capabilities&   V4L2_CAP_VBI_CAPTURE)
+            cap->type |= VID_TYPE_TELETEXT;

lib/libv4l1/libv4l1.c int v4l1_ioctl(int fd, unsigned long int request, · line 583

Quoted 10 lines

lib/libv4l1/libv4l1.c +10 -0

+        if (cap2->capabilities&   V4L2_CAP_VIDEO_OVERLAY)
+            cap->type |= VID_TYPE_OVERLAY;
+        if (fbuf.capability&   V4L2_FBUF_CAP_LIST_CLIPPING)
+            cap->type |= VID_TYPE_CLIPPING;
+
+        cap->channels = count_inputs(fd);
+
+        check_size(fd,
+&cap->maxwidth,&cap->maxheight);
+

No need to check size here, as we override that below, so this line can be dropped.

lib/libv4l1/libv4l1.c int v4l1_ioctl(int fd, unsigned long int request, · line 586

Quoted 3 lines

lib/libv4l1/libv4l1.c +3 -0

+
+    /*    result = SYS_IOCTL(fd, request, arg);*/
+

This can be dropped too.

Quoted 4 lines

lib/libv4l1/libv4l1.c +1 -0

+
 

/* override kernel v4l1 compat min / max size with our own more
accurate values */

And the override comment can be dropped to, as we no longer will be suing the v4l1 compat code check_size stuff.

lib/libv4l1/libv4l1.c int v4l1_ioctl(int fd, unsigned long int request, · line 598

Quoted 11 lines

lib/libv4l1/libv4l1.c +4 -1

@@ -500,7 +590,10 @@ int v4l1_ioctl(int fd, unsigned long int request,
 ...)
           cap->minheight = devices[index].min_height;
           cap->maxwidth  = devices[index].max_width;
           cap->maxheight = devices[index].max_height;
-        break;
+
+        done:
+            free(cap2);
+            break;
       }

No need to do this either when we drop the malloc.

Quoted 1 line

Quoted 6 lines

Quoted 2 lines

       case VIDIOCSPICT: {

Thanks& Regards,

Hans

- --
Regards,
Huzaifa Sidhpurwala, RHCE, CCNA (IRC: huzaifas) -----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.5 (GNU/Linux)
Comment: Using GnuPG with Red Hat - http://enigmail.mozdev.org/

iD8DBQFL86S5zHDc8tpb2uURAkJHAJ4vMGhdJNcgD9rFaZUtMqQvo80KsACfbSuv KrcNL6YjjUi7kchPHJ8gV84=
=aRtx
-----END PGP SIGNATURE-----
--
To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html