UNIX for Advanced & Expert Users

Greetings.

I have a question concerning the proper formation of a genisoimage commandline to prohibit write-back behavior to the original source files.

Consider the following typical usage example:

Code:

genisoimage -r -V "Some_Name" -cache-inodes -J -l -b isolinux/isolinux -c isolinux/boot.cat -no-emul-boot -boot-load-size 4 -boot-info-table -o /tmp/cdcopy.iso .

When run on a read-only (golden) source fileset, we get: First off, why is genisoimage by default writing back to the original source files in the first place (!); and, secondly, what might one call at the commandline when invoking genisoimage to prohibit this behavior? manpages seem to fail here...



Thanks for the help --

hi LinQ,

did i understand you correctly ?

- you create a bootable cd image iso and then you mount this on the system
- after when you run an executable that on the mount but its fail ?

@ygemici:

No, I'm just looking for a way to keep genisoimage from needlessly changing the master distro files while it's creating an iso.

That's it in a nutshell

ok

* so what is changing ? which files or what append ?

* and did you try different options?

Code:

-iso-level 3 -D -d -R -allow-multidot -allow-lowercase ..

@ygemici:

Thanks for the input.

As mentioned in the output from genisoimage, the file which commonly gets written to is isolinux.bin, ...although there might be others in certain instances (comments, anyone?)

BTW: The original citations were taken from the OP found in this serverfault thread. I was able to reproduce the output on my (offline) "distro-maker" using a similar commandline with the sourcefile partition set as read-only. If allowed, genisoimage will definitely do as it indicates; and the target sourcefile (isolinux.bin) will be altered.

There doesn't seem to be any help in the manpages regarding a commandline parameter which would suppress this behavior. Which of your above commandline parameter(s) might work to keep these writebacks from occurring? Is the entire string to be utilized as a kind of "panacea"???

In any event, it seems as though this is a widely-applicable issue; and, judging from the number of hits this thread had in just the first 24 hours (over 5K), I'm not the only one out here with some concern...

Anyone else seen this?

Thanks

ok you want to recreate the own iso-file but fot the "-boot-info-table" options trigger the mkisofs/genisoimage so it wants to regenerate the boot table located is in the your boot-image and then its fails because isolinux.bin is default read-only permission from iso or mounted iso.

if you dont need to edit the boot image and/or boot-info-table *(iso fs sys infors,size of boot image,checksum info and all its locations...)
so remove the -boot-info-table your commandline and your command then your process must be works.

but the default/recommend way , copy the contents of all files from iso to writable an empty (newly created) directory and then execute the default mkisofs/genisoimage commands on to the this directory.

good luck
regards
ygemici

A unionfs mount could effectively allow that folder to be "written" to, as well.