TITLE : Package management in jhalfs
ADDED : $Date$
BY    : Pierre Labastie

1. INTRODUCTION:

      There are several hints discussing package management for LFS, but
  nothing under jhalfs. There used to be a patch for PACO that I cannot
  find now. This is a modification, which allows to use a package manager
  inside jhalfs. I hope it is flexible enough to support several package
  managers. My implementation uses dpkg, from Debian, in a very crude way.
  Debian has a sophisticated package management system, which I have not
  tried to use here. For example, it should be usable with Pacman from
  Arch Linux (http://www.archlinux.org), as far as I remember from my old
  days with DIYL. I am sorry to say I have (almost) no experience with
  rpm, so I cannot tell whether it would fit.

2. OVERVIEW OF THE SYSTEM:

      For now, package management is only available for LFS. I plan to
  upgrade BLFS tools, but nothing usable right now. The other flavours of
  LFS do not seem very active, so there is no point in updating jhalfs
  for them.
      The first thing to do is to modify the install instructions of the
  chapter 6, 7 and 8 of the book so that the installed files end up in a
  directory other than `/'. We choose to call this directory by the name
  of the executed script, and to put the path to this directory in the
  PKG_DEST variable which is made available to the scriplets.
      Almost all the packages have a way to redirect the destination of
  the files they install at the `make install' stage with the variable
  DESTDIR. Furthermore, the authors of the book have been kind enough to
  flag the installation instructions with `remap=install'. This allows an
  xsl stylesheet to find those instructions. Then, places where `make '
  occurs (make followed by a space) are replaced by `make DESTDIR=$PKG_DEST '.
      Places where the book instructions move files into their destination
  are harder to deal with: it is possible to change all occurences of ` /' or
  `>/' (beginning of absolute paths) to `$PKG_DEST', but you end up moving
  files to non existent directories. There is no simple way to automatically
  create those directories, because you have sometimes to use the full path
  (instructions of the form `cp file dir') and sometimes only the dirname
  (instructions of the form `cp file1 file2'). So I am conservative and
  create  a reasonable subset of the FHS hierarchy into the destination
  directory. Empty directories should then be removed before packing the
  binary package.
      Supposing now that the scriptlets have been adequately modified, the
  package manager installation instructions have to be added at the end of
  chapter 5 and chapter 6. Furthermore, the administrative files and
  directories have to be created during the `Creating Directories' and
  `Creating Essential Files' stage. For all this, the user has to supply a
  file in docbook format, with the necessary instructions and enough
  information to download the tarball. A template is provided in the pkgmngt
  subdirectory.
      The last thing to do is to tell how to use the package manager. When
  the binary package is ready, the scriptlets call a shell function named
  `packInstall', which should pack the binary package and install it on the
  system. Note that nothing has been done to manage configuration files, 
  which are ususally treated specially by package managers. Depending on
  the book layout, it is sometimes possible to create those files afterwards,
  and sometimes not, which means that you have to check them after each
  upgrade. The user has to provide his own function. A template is provided
  in the pkgmngt subdirectory.

3. DETAILED INSTRUCTIONS:

      Before beginning, you should know which package manager you want, where
  to get the sources, and how to use it for:
  a) Making a package from a directory tree. Usually, there is some control
     file containing the version, pacakager, build system (32 or 64 bits at
     least) or other more or less usefull but mandatory bits of information
     which you should understand.
  b) Unpack the package.

      Second, you ought to have a basic knowledge of bash scripting and
  docbook-xml writing, because you have to write a bash function for packing
  and unpacking the package, and a set of instructions to install the PM.