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diff --git a/doc/genisoimage/README.hide b/doc/genisoimage/README.hide new file mode 100644 index 0000000..ae8521b --- /dev/null +++ b/doc/genisoimage/README.hide @@ -0,0 +1,208 @@ +Hiding files on a CD +===================== + +This document attempts to show how to hide files from being seen by an +operating system accessing a CD as an ISO9660/Rock Ridge, Joliet or HFS +CD. It also highlights some of the limitations ... + +Note: this document is about the various -hide options - not be confused with +the -hidden options. + +The -hidden options set the 'EXISTENCE' bit in the directory entry which +means the file or directory will be invisible - unless some special option +is used to mount or view the CD - Linux has the 'unhide' mount option to +make these files visible. i.e. the directory entry exists on the CD. + +With hindsight, to avoid confusion with the -hidden option, it would have +been better to chose an option name like '-omit' instead of '-hide'... + +The various -hide options actually exclude the relevant directory entry +from the directory tree. Therefore, it is not possible to access a file +or directory that has be hidden with the -hide option when the ISO9600/Rock +Ridge directory is mounted - because the directory entry does not exist on the +CD (but the file data does). You would probably be able to access this file +or directory when mounted as a Joliet or HFS CD (depending on other options +used). Similarly, a directory entry hidden with the -hide-joliet option +will not be accessible when mounted as an Joliet CD. Similarly for -hide-hfs +etc. + +If you don't want a file or directory to appear on the CD at all, then use the +-exclude options, not the -hide options (genisoimage completely ignores any +file/directory excluded with the -exclude options). + + +Using the hide options +====================== + +There are 6 hide options: + +-hide Hide a file/directory from the ISO9660/Rock Ridge directory +-hide-list As above, but read file names from a file +-hide-joliet Hide a file/directory from the Joliet directory +-hide-joliet-list As above, but read file names from a file +-hide-hfs Hide a file/directory from the HFS directory +-hide-hfs-list As above, but read file names from a file + +You can use the -hide, -hide-joliet and/or -hide-hfs options as many times +as you like on the command line, but if you have many files to hide, then +it may be better to put your file names in a file (one per line) and use +the corresponding 'list' option. You can also use the three -hide-list options +as many times as you want. + +The arguments to the -hide options are either the 'basename' or the 'whole +path name' of a file. That is, if you use the option: + +% genisoimage -hide ABC [-other-options] CD_directory + +then any file with the name ABC will be hidden. If you want to be more +specific, then use the whole name - as seen by genisoimage e.g.: + +% genisoimage -hide CD_directory/XYZ/ABC [-other-options] CD_directory + +will hide just the file 'CD_directory/XYZ/ABC' - not any other file called +'ABC' that might exist under 'CD_directory'. However, if your command line +is like: + +% genisoimage -hide CD_directory/XYZ/ABC [-other-options] ./CD_directory + +Then the file 'CD_directory/XYZ/ABC' will not be hidden because as far as +genisoimage is concerned. Its whole path is actually './CD_directory/XYZ/ABC'. + +You can use wild cards in the -hide arguments. + +If the file name to be hidden is a directory, then the directory and all +its contents are hidden. + +The main use of the hide options is on a multi platform (hybrid CD) to hide +various files/directories that are operating system specific from been seen +on the CD when mounted on another OS. i.e. You may want to hide Macintosh +executables from being seen when the CD is mounted as a Joliet CD on a PC etc. + +For example, say we want to create a ISO9660/Rock Ridge, Joliet, HFS hybrid +CD from files/directories in the directory called 'cd_dir' - which are: + +MAC/ +MAC/app +MAC/data/ +MAC/data/file1 +PC/ +PC/app +PC/data/ +PC/data/file1 +UNIX/ +UNIX/app +UNIX/data +UNIX/data/file1 +COMMON/ +COMMON/some_files + +We could use the command line: + +% genisoimage -r -J -hfs -hide MAC -hide PC -hide-joliet MAC \ + -hide-joliet UNIX -hide-hfs PC -hide-hfs UNIX -o cd.iso cd_dir + +This will give a CD that when mounted as a Rock Ridge CD, you will only +see the directories UNIX and COMMON, as a Joliet CD the directories +PC and COMMON, and as an HFS CD the directories MAC and COMMON. + +If you also had the three files in the current directory called README.hfs, +README.joliet and README.unix - but you wanted to have each of these +files appear as just 'README' when mounted, then you could use the above +command line with the following: + +% genisoimage -r -J -hfs -graft-points -hide MAC -hide PC -hide-joliet MAC \ + -hide-joliet UNIX -hide-hfs PC -hide-hfs UNIX \ + -hide README.hfs -hide README.joliet -hide-joliet README.hfs \ + -hide-joliet README.uni -hide-hfs README.joliet -hide-hfs README.unix \ + README=README.hfs README=README.joliet README=README.unix \ + -o cd.iso cd_dir + +Note: we've used the -graft-points option as we're using the '=' syntax +to insert the files called README.hfs, README.joliet and README.unix as +'README' + +The resulting CD when mounted as a Rock Ridge CD, will have the directories +UNIX and COMMON - with the file called README - which was originally +called README.unix. + +However, in most circumstances, it would be better to have the contents +of each of the OS specific directories (plus the contents of the COMMON +directory) to appear at the top level of the CD. i.e. when the CD is mounted +(as ISO9660/Rock Ridge, Joliet or HFS) it has the contents: + +README +app +data/file1 +some_files + +Unfortunately, this is not as straight forward as it may seem - i.e. doing +the following may seem OK, but it won't work - for reasons I'll explain +later: + +It gets a bit messy using the -graft-points syntax above, so we'll assume +each of the MAC, UNIX and PC directories contain the correct README, We'll +also change to the 'cd_dir' directory and use the command: + +genisoimage -r -J -hfs -hide MAC -hide PC -hide-joliet MAC \ + -hide-joliet UNIX -hide-hfs PC -hide-hfs UNIX \ + -o cd.iso MAC PC UNIX COMMON + +You will get errors like: + +genisoimage: Error: UNIX/README and MAC/README have the same Rock Ridge name +... +genisoimage: Unable to sort directory + +This is because you can not hide "pathspecs" that are directories ("pathspecs" +are file names given on the command line, or in a path-list file). This a +"feature" of genisoimage. In this case nothing is actually hidden at all. + +So you might think that the following may work: + +genisoimage -r -J -hfs -hide "MAC/*" -hide "PC/*" -hide-joliet "MAC/*" \ + -hide-joliet "UNIX/*" -hide-hfs "PC/*" -hide-hfs "UNIX/*" \ + -o cd.iso MAC PC UNIX COMMON + +which may appear to work - but when the CD is mounted as an ISO9660/Rock Ridge +or Joliet CD, then the directory "data" is missing. + +Again this is a feature of genisoimage - the directories PC/data and UNIX/data +are mapped by genisoimage to the same output directory called "/data" - the +various "hide" flags are stored with this directory info - in this case as +the output directory "/data" is first hidden from the ISO9660/Rock Ridge and +then the Joliet directory, the net result is that "/data" gets hidden from +both directories ... the way genisoimage hides HFS directories is slightly +different, so in this case the directory "data" exists on the HFS volume +and contains the correct contents. + +However, it is possible to obtain the required result, but we have to be +careful about hiding multiple input directories that map to a single output +directory. + +To do this we have to hide just the files in these directories (or more +accurately, all the non-directories). This is best done by using lists of +files to hide for example: + +find PC -type f -print > pc.list +find UNIX -type f -print > unix.list +find MAC -type f -print > mac.list + +genisoimage -r -J -hfs -hide-list pc.list -hide-list mac.list \ + -hide-joliet-list unix.list -hide-joliet-list mac.list \ + -hide-hfs-list pc.list -hide-hfs-list unix.list \ + -o cd.iso MAC PC UNIX COMMON + +i.e. instead of trying to hide a directory and letting genisoimage hide its +contents, we explicitly hide all the files in the directory, but not the +directory and any of its sub-directories. + +This will work for the above input files, but if your directory trees contain +symbolic links and/or directories that will not get merged, then the hide lists +will have to be tailored to get the required result. + + +James Pearson 22-Nov-2001 + +Any comments/problems to j.pearson@ge.ucl.ac.uk + +Modified for cdrkit/genisoimage by Eduard Bloch, Wed, 27 Dec 2006 |