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Mythwebburn - won't burn DVD
http://forum.linhes.org/viewtopic.php?f=6&t=6802		 Page 1 of 1
Author:  cmaines [ Sun Nov 06, 2005 3:44 pm ]
Post subject:  Mythwebburn - won't burn DVD
Although the mythwebburn script seems pretty near perfect in R5A22, it stops when it gets to the point where it should burn my DVD-R. I get the following error:

Burning DVD-R image
Sent UDP/XML packet to IP 255.255.255.255 and port: 6948
:-( unable to open64("/dev/dvd",O_RDONLY): Permission denied
***********************************
MythTV BurnDVD stopped due to error
***********************************
Sent UDP/XML packet to IP 255.255.255.255 and port: 6948



I can easily write a DVD-R from an xterm window using the growisofs command, but I'd rather it all happen within the mythwebburn script. I'm pretty sure my DVD writer is actually mounted as /dev/cdrom and not as /dev/dvd. What would be the best course of action: relabel my DVD writer as /dev/dvd and risk things elsewhere not working properly, or alter the /dev/dvd line within the mythwebburn script. If the latter, where do I find it - I've looked in all the .php files and .conf files I can find that are related to DVD burning.

Thanks.
Author:  Liv2Cod [ Sun Nov 06, 2005 6:49 pm ]
Post subject: 
Maybe add another device for /dev/dvd. I'm pretty sure it's OK to have the same name for two different devices.

Here are the relevant entries in my box:

Code:
root@mythtv:~# ll /dev/dvd /dev/cdrom
lrwxrwxrwx  1 root cdrom 8 Aug  6 22:31 /dev/cdrom -> /dev/hdb
lrwxrwxrwx  1 root cdrom 8 Aug  6 22:31 /dev/dvd -> /dev/hdb
Author:  cmaines [ Sun Nov 13, 2005 1:26 pm ]
Post subject: 
My box also has very similar entries, ie. - both /dev/cdrom and /dev/dvd are linked (if that's the correct term" to /dev/hda - so I don't think that's the problem. I put a blank DVD-R in the drive and tried

Code:
# mount /dev/hdc /mnt/dvd


but it said it was read-only and couldn't mount the drive. Are there other "devices" that are defined as DVD writeable that would allow me to mount the blank DVD-R?
Author:  tjc [ Sun Nov 13, 2005 4:35 pm ]
Post subject: 
Liv2Cod wrote:
Maybe add another device for /dev/dvd. I'm pretty sure it's OK to have the same name for two different devices.

Those are symbolic links and you can have as many of them as you want to the same file system object. For example:
Code:
root@black2:~# ls -al /dev/cdrom /dev/dvd /dev/hdc
lrwxrwxrwx  1 root cdrom     8 Nov  6 18:42 /dev/cdrom -> /dev/hdc
lrwxrwxrwx  1 root cdrom     8 Nov  6 18:42 /dev/dvd -> /dev/hdc
brw-rw----  1 root cdrom 22, 0 May  7  2004 /dev/hdc

Here you see two symbolic links cdrom and dvd (notice the 'l' in the first colum) with the same destination, /dev/hdc. The 'b' in the first column for that tells you that it's a "block device" - i.e. a disk or tape of some kind.
Author:  tjc [ Sun Nov 13, 2005 4:41 pm ]
Post subject: 
cmaines wrote:
My box also has very similar entries, ie. - both /dev/cdrom and /dev/dvd are linked (if that's the correct term" to /dev/hda

OK, that sounds screwy, since /dev/hda (the primary master IDE drive) is normally your hard disk. Do this:
Code:
grep [hs]d[abcdefgh][:1234567] /var/log/dmesg
and post the results here.
Author:  cmaines [ Sun Nov 13, 2005 5:45 pm ]
Post subject: 
tjc:

I have a SATA drive instead of an IDE drive. Consequently my hard drive is actually /dev/sda.

Here are the results of the grep:

Code:
   ide0: BM-DMA at 0x4000-0x4007, BIOS settings: hda:DMA, hdb:pio
    ide1: BM-DMA at 0x4008-0x400f, BIOS settings: hdc:pio, hdd:pio
hda: _NEC DVD_RW ND-3540A, ATAPI CD/DVD-ROM drive
hda: ATAPI 48X DVD-ROM DVD-R CD-R/RW drive, 2048kB Cache, UDMA(33)
SCSI device sda: 490234752 512-byte hdwr sectors (251000 MB)
SCSI device sda: drive cache: write back
SCSI device sda: 490234752 512-byte hdwr sectors (251000 MB)
SCSI device sda: drive cache: write back
 sda: sda1 sda2 < sda5 sda6 sda7 >
Adding 2931820k swap on /dev/sda5.  Priority:-1 extents:1
EXT3 FS on sda1, internal journal
EXT3 FS on sda7, internal journal
Author:  tjc [ Sun Nov 13, 2005 9:37 pm ]
Post subject: 
OK, I kind of figured that was one of the possibilities. What does this show?
Code:
ls -al /dev/cdrom /dev/dvd /dev/hda
grep cdrom /etc/group
Author:  TB12 [ Sat Nov 26, 2005 1:56 pm ]
Post subject: 
I am getting the same error when I try Mythwebburn. I just installed R5a26. All else seems to work.

mythtv@mythtv:~$ ls -al /dev/cdrom /dev/dvd /dev/hda
lrwxrwxrwx 1 root cdrom 8 Nov 25 20:20 /dev/cdrom -> /dev/hdc
lrwxrwxrwx 1 root cdrom 8 Nov 25 20:20 /dev/dvd -> /dev/hdc
brw-rw---- 1 root disk 3, 0 May 7 2004 /dev/hda
mythtv@mythtv:~$ grep cdrom /etc/group
cdrom:*:24:mythtv,tb12
mythtv@mythtv:~$


mythtv@mythtv:~$ grep [hs]d[abcdefgh][:1234567] /var/log/dmesg
ide0: BM-DMA at 0xfff0-0xfff7, BIOS settings: hda:DMA, hdb:pio
ide1: BM-DMA at 0xfff8-0xffff, BIOS settings: hdc:DMA, hdd:pio
hda: Maxtor 6L200R0, ATA DISK drive
hdc: MATSHITADVD-RAM SW-9585, ATAPI CD/DVD-ROM drive
hda: max request size: 1024KiB
hda: 398297088 sectors (203928 MB) w/16384KiB Cache, CHS=24792/255/63, UDMA(66)
hda: cache flushes supported
hda: hda1 hda2 hda3 hda4
hdc: ATAPI 40X DVD-ROM DVD-R-RAM CD-R/RW drive, 2048kB Cache, UDMA(66)
Adding 996020k swap on /dev/hda2. Priority:-1 extents:1
EXT3 FS on hda1, internal journal
EXT3 FS on hda4, internal journal

Any ideas??
Author:  nigelpearson [ Sat Nov 26, 2005 6:11 pm ]
Post subject: 
TB, if your CD/DVD is /dev/hda, then having /dev/cdrom and /dev/dvd point to /dev/hdc won't do much. Try this as root:

cd /dev
rm cdrom dvd
ln -s /dev/hdc cdrom
ln -s /dev/hdc dvd
chmod 666 hdc

and then try to burn the disk again (the following command will be much faster then re-running the burn scripts)

growisofs -Z /dev/dvd -dvd-video -V "MythTV BurnDVD" /myth/mythburn/DVD
Author:  TB12 [ Sat Nov 26, 2005 9:39 pm ]
Post subject: 
It worked!!

Thanks, Nigel.

Knoppmyth...so butter.
Author:  intricateenigma [ Wed Nov 30, 2005 7:56 pm ]
Post subject: 
For anyone else out there facing this problem, you might also consider adding the user that will be running the script to the cdrom group.

For me, /dev/dvd links to /dev/hdc. If I run "ls -a /dev/hdc" I get:

Code:
brw-rw----  1 root cdrom 22, 0 May  7  2004 /dev/hdc


In a knoppmyth install (I have R5A16) mythtv is in the cdrom group by default, however, the web server runs as www-data. To allow burning dvd's from the webserver su into root or use sudo and run the following command:

Code:
usermod -Gcdrom www-data


This will work for any user you want to have cdrom rw access by substituting the username in for "www-data". This is a little more secure as it still restricts who can write to the cdrom drive. To change your rwx permissions to match mine, as root you would run:

Code:
chmod 660 /dev/hdc
Author:  tjc [ Wed Nov 30, 2005 10:31 pm ]
Post subject: 
This is definitely the more correct solution.
Author:  mgpaulus [ Thu Feb 09, 2006 1:18 pm ]
Post subject: 
intricateenigma wrote:
For anyone else out there facing this problem, you might also consider adding the user that will be running the script to the cdrom group.

For me, /dev/dvd links to /dev/hdc. If I run "ls -a /dev/hdc" I get:

Code:
brw-rw----  1 root cdrom 22, 0 May  7  2004 /dev/hdc


In a knoppmyth install (I have R5A16) mythtv is in the cdrom group by default, however, the web server runs as www-data. To allow burning dvd's from the webserver su into root or use sudo and run the following command:

Code:
usermod -Gcdrom www-data


This will work for any user you want to have cdrom rw access by substituting the username in for "www-data". This is a little more secure as it still restricts who can write to the cdrom drive. To change your rwx permissions to match mine, as root you would run:

Code:
chmod 660 /dev/hdc


This doesn't seem to work in my instance. I have added www-data to the cdrom group, and if I were to 'su - www-data' and then do an 'id', I get:
uid=33(www-data) gid=33(www-data) groups=24(cdrom),33(www-data)

However, when I put an 'id' command in mythtvburn.sh, this is what is output:
uid=33(www-data) gid=33(www-data) groups=33(www-data)

So, whereever mythburn is being invoked, it is not picking up the cdrom group from /etc/groups, and therefore, I still get "Permission denied".
Author:  mgpaulus [ Thu Feb 09, 2006 1:51 pm ]
Post subject: 
Nevermind the above. I stopped and restarted my apache server, and now the www-data user has cdrom in its group:

uid=33(www-data) gid=33(www-data) groups=24(cdrom),33(www-data)
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