Hi,
In September Laurence Tratt came up with a diff to implement an
kern.video.record switch for sysctl(8). The implementation was only
for uvideo(4), and hence we wanted to lift that up to the video(4)
level, but we were not able to get a good implementation together back
then.
I reviewed this again, and I think this implementation should be
consistent on a video(4) level now. Some points of the
characteristics:
* The implementation acts on video(4) level, so it will serve
all it's drivers without the need to modify an existing
video(4) driver.
* The implementation is more or less equal to what
kern.audio.record does.
* The video data will be blanked on the fly by zeroing the
frame buffer data in video(4) before passing it to userland.
* Hence the switch can be applied also on a open video stream.
TODOs in a second step:
* I haven't done the man page updates in this diff.
* The blanking could be improved to not only zero out the frame
buffer data, but generate a black image. That would require
some similar helper functions like audio(4) has, to create
silence: audio_calc_sil(), audio_fill_sil(). Of course we
would need to distinguish between compressed and uncompressed
video data in there.
I have quickly tested the diff here with two cams, and it works fine
for me so far.
Comments, testers, OKs?
Cheers,
Marcus
Index: sys/dev/video.c
===================================================================
RCS file: /cvs/src/sys/dev/video.c,v
retrieving revision 1.44
diff -u -p -u -p -r1.44 video.c
--- sys/dev/video.c 16 May 2020 10:47:22 -0000 1.44
+++ sys/dev/video.c 16 Dec 2020 14:05:11 -0000
@@ -51,6 +51,7 @@ struct video_softc {
int sc_fsize;
uint8_t *sc_fbuffer;
+ caddr_t sc_fbuffer_mmap;
size_t sc_fbufferlen;
int sc_vidmode; /* access mode */
#define VIDMODE_NONE 0
@@ -78,6 +79,11 @@ struct cfdriver video_cd = {
NULL, "video", DV_DULL
};
+/*
+ * Global flag to control if video recording is enabled by kern.video.record.
+ */
+int video_record_enable = 0;
+
int
videoprobe(struct device *parent, void *match, void *aux)
{
@@ -191,6 +197,8 @@ videoread(dev_t dev, struct uio *uio, in
/* move no more than 1 frame to userland, as per specification */
size = ulmin(uio->uio_resid, sc->sc_fsize);
+ if (!video_record_enable)
+ bzero(sc->sc_fbuffer, size);
error = uiomove(sc->sc_fbuffer, size, uio);
sc->sc_frames_ready--;
if (error)
@@ -205,6 +213,7 @@ int
videoioctl(dev_t dev, u_long cmd, caddr_t data, int flags, struct proc *p)
{
struct video_softc *sc;
+ struct v4l2_buffer *vb = (struct v4l2_buffer *)data;
int unit, error;
unit = VIDEOUNIT(dev);
@@ -299,6 +308,8 @@ videoioctl(dev_t dev, u_long cmd, caddr_
}
error = (sc->hw_if->dqbuf)(sc->hw_hdl,
(struct v4l2_buffer *)data);
+ if (!video_record_enable)
+ bzero(sc->sc_fbuffer_mmap + vb->m.offset, vb->length);
sc->sc_frames_ready--;
break;
case VIDIOC_STREAMON:
@@ -408,6 +419,10 @@ videommap(dev_t dev, off_t off, int prot
if (pmap_extract(pmap_kernel(), (vaddr_t)p, &pa) == FALSE)
panic("videommap: invalid page");
sc->sc_vidmode = VIDMODE_MMAP;
+
+ /* store frame buffer base address for later blanking */
+ if (off == 0)
+ sc->sc_fbuffer_mmap = p;
return (pa);
}
Index: sys/kern/kern_sysctl.c
===================================================================
RCS file: /cvs/src/sys/kern/kern_sysctl.c,v
retrieving revision 1.384
diff -u -p -u -p -r1.384 kern_sysctl.c
--- sys/kern/kern_sysctl.c 7 Dec 2020 16:55:29 -0000 1.384
+++ sys/kern/kern_sysctl.c 16 Dec 2020 14:05:12 -0000
@@ -114,6 +114,7 @@
#endif
#include "audio.h"
+#include "video.h"
#include "pf.h"
extern struct forkstat forkstat;
@@ -125,6 +126,9 @@ extern long numvnodes;
#if NAUDIO > 0
extern int audio_record_enable;
#endif
+#if NVIDEO > 0
+extern int video_record_enable;
+#endif
int allowkmem;
int allowdt;
@@ -141,6 +145,9 @@ int sysctl_cptime2(int *, u_int, void *,
#if NAUDIO > 0
int sysctl_audio(int *, u_int, void *, size_t *, void *, size_t);
#endif
+#if NVIDEO > 0
+int sysctl_video(int *, u_int, void *, size_t *, void *, size_t);
+#endif
int sysctl_cpustats(int *, u_int, void *, size_t *, void *, size_t);
int sysctl_utc_offset(void *, size_t *, void *, size_t);
@@ -379,6 +386,7 @@ kern_sysctl(int *name, u_int namelen, vo
case KERN_FILE:
case KERN_WITNESS:
case KERN_AUDIO:
+ case KERN_VIDEO:
case KERN_CPUSTATS:
break;
default:
@@ -642,6 +650,11 @@ kern_sysctl(int *name, u_int namelen, vo
return (sysctl_audio(name + 1, namelen - 1, oldp, oldlenp,
newp, newlen));
#endif
+#if NVIDEO > 0
+ case KERN_VIDEO:
+ return (sysctl_video(name + 1, namelen - 1, oldp, oldlenp,
+ newp, newlen));
+#endif
case KERN_CPUSTATS:
return (sysctl_cpustats(name + 1, namelen - 1, oldp, oldlenp,
newp, newlen));
@@ -2440,6 +2453,21 @@ sysctl_audio(int *name, u_int namelen, v
return (ENOENT);
return (sysctl_int(oldp, oldlenp, newp, newlen, &audio_record_enable));
+}
+#endif
+
+#if NVIDEO > 0
+int
+sysctl_video(int *name, u_int namelen, void *oldp, size_t *oldlenp,
+ void *newp, size_t newlen)
+{
+ if (namelen != 1)
+ return (ENOTDIR);
+
+ if (name[0] != KERN_VIDEO_RECORD)
+ return (ENOENT);
+
+ return (sysctl_int(oldp, oldlenp, newp, newlen, &video_record_enable));
}
#endif
Index: sys/sys/sysctl.h
===================================================================
RCS file: /cvs/src/sys/sys/sysctl.h,v
retrieving revision 1.212
diff -u -p -u -p -r1.212 sysctl.h
--- sys/sys/sysctl.h 7 Nov 2020 05:24:20 -0000 1.212
+++ sys/sys/sysctl.h 16 Dec 2020 14:05:13 -0000
@@ -189,7 +189,8 @@ struct ctlname {
#define KERN_PFSTATUS 86 /* struct: pf status and stats
*/
#define KERN_TIMEOUT_STATS 87 /* struct: timeout status and
stats */
#define KERN_UTC_OFFSET 88 /* int: adjust RTC time to UTC
*/
-#define KERN_MAXID 89 /* number of valid kern ids */
+#define KERN_VIDEO 89 /* struct: video properties */
+#define KERN_MAXID 90 /* number of valid kern ids */
#define CTL_KERN_NAMES { \
{ 0, 0 }, \
@@ -281,6 +282,7 @@ struct ctlname {
{ "pfstatus", CTLTYPE_STRUCT }, \
{ "timeout_stats", CTLTYPE_STRUCT }, \
{ "utc_offset", CTLTYPE_INT }, \
+ { "video", CTLTYPE_STRUCT }, \
}
/*
@@ -318,6 +320,17 @@ struct ctlname {
#define KERN_AUDIO_MAXID 2
#define CTL_KERN_AUDIO_NAMES { \
+ { 0, 0 }, \
+ { "record", CTLTYPE_INT }, \
+}
+
+/*
+ * KERN_VIDEO
+ */
+#define KERN_VIDEO_RECORD 1
+#define KERN_VIDEO_MAXID 2
+
+#define CTL_KERN_VIDEO_NAMES { \
{ 0, 0 }, \
{ "record", CTLTYPE_INT }, \
}
Index: sbin/sysctl/sysctl.c
===================================================================
RCS file: /cvs/src/sbin/sysctl/sysctl.c,v
retrieving revision 1.253
diff -u -p -u -p -r1.253 sysctl.c
--- sbin/sysctl/sysctl.c 17 Nov 2020 12:11:04 -0000 1.253
+++ sbin/sysctl/sysctl.c 16 Dec 2020 12:54:40 -0000
@@ -130,6 +130,7 @@ struct ctlname machdepname[] = CTL_MACHD
#endif
struct ctlname ddbname[] = CTL_DDB_NAMES;
struct ctlname audioname[] = CTL_KERN_AUDIO_NAMES;
+struct ctlname videoname[] = CTL_KERN_VIDEO_NAMES;
struct ctlname witnessname[] = CTL_KERN_WITNESS_NAMES;
char names[BUFSIZ];
int lastused;
@@ -219,6 +220,7 @@ void print_sensor(struct sensor *);
int sysctl_chipset(char *, char **, int *, int, int *);
#endif
int sysctl_audio(char *, char **, int *, int, int *);
+int sysctl_video(char *, char **, int *, int, int *);
int sysctl_witness(char *, char **, int *, int, int *);
void vfsinit(void);
@@ -517,6 +519,11 @@ parse(char *string, int flags)
if (len < 0)
return;
break;
+ case KERN_VIDEO:
+ len = sysctl_video(string, &bufp, mib, flags, &type);
+ if (len < 0)
+ return;
+ break;
case KERN_WITNESS:
len = sysctl_witness(string, &bufp, mib, flags, &type);
if (len < 0)
@@ -1766,6 +1773,7 @@ struct list shmlist = { shmname, KERN_SH
struct list watchdoglist = { watchdogname, KERN_WATCHDOG_MAXID };
struct list tclist = { tcname, KERN_TIMECOUNTER_MAXID };
struct list audiolist = { audioname, KERN_AUDIO_MAXID };
+struct list videolist = { videoname, KERN_VIDEO_MAXID };
struct list witnesslist = { witnessname, KERN_WITNESS_MAXID };
/*
@@ -2813,6 +2821,25 @@ sysctl_audio(char *string, char **bufpp,
return (-1);
mib[2] = indx;
*typep = audiolist.list[indx].ctl_type;
+ return (3);
+}
+
+/*
+ * Handle video support
+ */
+int
+sysctl_video(char *string, char **bufpp, int mib[], int flags, int *typep)
+{
+ int indx;
+
+ if (*bufpp == NULL) {
+ listall(string, &videolist);
+ return (-1);
+ }
+ if ((indx = findname(string, "third", bufpp, &videolist)) == -1)
+ return (-1);
+ mib[2] = indx;
+ *typep = videolist.list[indx].ctl_type;
return (3);
}
