Re: mkisofs aborts but exit value is 0

[scdbackup@gmx.net]

Hi,

> Then you know that mkisofs does not try to read
> zero sized files.

This might be true if mkisofs is aware of the 0 size.
But in my problem situation, the size known to mkisofs
is not the current size of the file when it comes to reading.

I can prove : in this situation even 0 sized files get read.

Sorry for being such a Rechthaber (= person who insists in being right)
but after browsing up and down in the code of mkisofs i would have
been really astonished if i would have been unable to demonstrate the
effect. 8-)


I tested with mkisofs 2.01 (i686-pc-linux-gnu) and with 2.01.01a03 :

  $ ls -l /dvdbuffer/test
  -rw-r--r--    1 thomas   thomas   1610612736 Jul 10 20:06 fatso
  -rw-r--r--    1 thomas   thomas          4 Aug  4 13:20 stretch

  $ mkisofs  -J -joliet-long -l -allow-leading-dots -R -D -graft-points \
             /dvdbuffer/test/fatso /dvdbuffer/test/stretch \
              >/dev/null

While mkisofs was reading file fatso, 
  ...
    12.71% done, estimate finish Thu Aug  4 13:25:11 2005
    13.35% done, estimate finish Thu Aug  4 13:25:10 2005
  ...

i executed

  $ echo -n >/dvdbuffer/test/stretch
  $ ls -l /dvdbuffer/test
  -rw-r--r--    1 thomas   thomas   1610612736 Jul 10 20:06 fatso
  -rw-r--r--    1 thomas   thomas          0 Aug  4 13:24 stretch

and half a minute later mkisofs ran into the "cannot read" situation :

  mkisofs: Inappropriate ioctl for device. cannot read from '/dvdbuffer/test/stretch'

So it read the file despite its size was 0 at the time of fopen().


I believe that the non-"Success" error message is due
to a remnant error number from some previous system call.
Since your announced code change covers this issue by
                seterrno(0);
i introduced it into my copy of 2.01.01a3.

Now the error message is :

  mkisofs: File too large. cannot read from '/dvdbuffer/test/stretch'

An averagely skilled user would be astonished after executing this :

  $ ls -l /dvdbuffer/test/stretch
  -rw-r--r--   1 thomas  thomas         0 Aug  4 16:04 /dvdbuffer/test/stretch


I rest my case.


Have a nice day :)

Thomas