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Diffstat (limited to 'docs/example_script')
| -rw-r--r-- | docs/example_script | 73 |
1 files changed, 71 insertions, 2 deletions
diff --git a/docs/example_script b/docs/example_script index 111b0d8..221c888 100644 --- a/docs/example_script +++ b/docs/example_script @@ -1,7 +1,52 @@ #!/bin/sh -# List the soft prerequisites here. So if there's something you know -# should be run first iff it exists. +# +# This script is run inside of the initramfs environment during the +# system boot process. It is installed there by 'mkinitramfs'. The +# package that owns it may opt to install it in either an appropriate +# location under "/usr/share/initramfs-tools/scripts/", or a similar +# location under "/etc/mkinitramfs/scripts/", depending upon whether +# it should be considered to be a user modifiable conffile or not. +# +# TODO: How do we deal with the case where the package that installed +# this has been removed but not purged, if we always arbitrarily +# copy all of these scripts into the initramfs? +# +# * The available toolset is limited inside this environment... +# +# TODO: document that toolset in the man page. +# +# * /dev, /proc, and /sys are already mounted. / is a ?? ro/rw +# filesystem... etc. more documentation. +# +# * It is expected that /proc and /sys will be umounted before +# changing over to the real root file system, so you must not keep +# any files open on them beyond these scripts. +# +# * You may like to strip these documentation comments from this +# example if you take it for a template, to save a little space in +# the initramfs, since nobody will ever read it from inside of +# there anyhow. +# + +# +# The environment contains at least the following variables: +# +# TODO: Decide what environment variables are meaningful and defined +# in this context, then document them as part of the interface. +# +# Because this script will be run as a full separate process, rather +# than sourced inside the context of the driver script, if it needs to +# pass information to another script that may run after it, it must do +# so by writing data to a file location known to both scripts. Simply +# setting an environment variable will not work. +# + +# +# List the soft prerequisites here. This is a space separated list of +# names, of scripts that are in the same directory as this one, that +# must be run before this one can be. +# PREREQ="" prereqs() @@ -18,4 +63,28 @@ prereqs) esac # Do the work here. + echo "Got here!" + +# Handle an error: + +if [ -n "$an_error_occured" ]; +then + # + # TODO: Do we need 'warn()', 'error()', and/or 'fatal()' for this? + # I think we ultimately do, and that they need to be in their own + # well-documented location so that an overlay can override them. + # Think 'usplash' progress updates. + # + echo "An error occured in $0: $an_error_occured" >&2 + exit 1 + # + # TODO: Decide if different error codes are meaningful, what they + # mean, and what the semantics of them are wrt 'init' pass + # or panic. Consider naming the error values with mnemonic + # symbols rather than magic numbers. + # +fi + +exit 0 + |