#!/bin/bash
# Original...
# Copyright (c) 2000,2004 Matthias S. Benkmann <article AT winterdrache DOT de>
# You may do everything with this code except misrepresent its origin.
# PROVIDED `AS IS' WITH ABSOLUTELY NO WARRANTY OF ANY KIND!

# Copyright (C) 2014 Steve Youngs <steve@steveyoungs.com>
#
#  Actually there's not much left of Matt's original script... pretty
#  much a complete re-write here. :)

### What this is and what it does:
#
#  It is a wrapper around the install binary that comes with the
#  coreutils package.  It is designed to catch the most common
#  problems that pkgusr will face during a package install.
#
#  By far, the most common thing this script catches are setuid/gid
#  installs.  What we do is strip the setuid/gid bit off of the --mode
#  option and then go ahead with the install.  So the file is still
#  installed, there'll be no error, it will just not be setuid/gid.
#
#  It also sanitises the --owner and --group options.  With the former,
#  it changes it to the name of the pkgusr, and with the latter it
#  tests if the group is one of the groups that pkgusr belongs to, and
#  if it isn't, change the option to the pkgusr's current active group.
#
#  It only allows pkgusrs to create directories that don't already
#  exist.  This stops those packages that try to reset permissions on
#  main system directories.
#
#  It optionally suppresses installing anything into /**/share/locale.
#  See `## locale suppression' below for more details.
#
#  ******************************
#  *** S P E C I A L  N O T E ***
#  ******************************
#
#  Whenever this script changes something on the install command line
#  it is reported in the build logs.  Everything is prefixed with
#  '***' so always grep your logs for that after any and every package
#  install to see if there is anything you need to take action on.
#
###

### Where this differs from Matt's original script:
#
#  setuid etc: Matt's script only tested for 4755, 4775, 4711, and
#  nothing else.  This script tests and does something about _ALL_
#  file mode possibilities, including modes set via symbols instead of
#  octal code.
#
#  owner/group: Matt simply dropped these options if they were present.
#  This script tries to keep them if possible by resetting to a safer
#  alternative.  Both names and UIDs/GIDs are supported.
#
#  locale directories: Matt's approach was to convert any newly created
#  directory under /usr/share/locale to an "install" directory.  The
#  problem with that is the directories were not owned by root because
#  they were set by the pkgusr. That would allow one pkgusr to delete
#  another's files in that directory.
#
#  My approach to locale directories is simple... Just don't install
#  them.  There are three situations where they are needed...
#
#    1. You're multi-lingual and like switching between languages.
#    2. English is not your 1st or preferred language. (or you can't
#       tollerate en_US)
#    3. To satisfy glibc's test suite.
#
#  For me, #3 is the only one that is relevant.  But don't worry,
#  it is configurable via an environment variable.  You can turn on
#  locale installs either globally or for individual packages.  See
#  `## locale suppression' below and in /etc/pkgusr/bash_profile.
#
#  man pages: Matt tried to catch dups going into /usr/share/man/man?/.
#  I'm not bothering with this as it was too much of a "one-off" type
#  of occurance to have it scripted.
#
#  Running the script as root:  Matt allows it, I don't.
#
###

## Preserve the original command line.
pristinecmd=($@)
cmdopts=""

## Find the real install.
DAISY_CHAIN=""
for p in $(type -ap install) ; do
    if [ ! $p -ef $0 ]; then
	DAISY_CHAIN=$p
	break
    fi
done

if [ ! -n "$DAISY_CHAIN" ]; then
    echo 1>&2 '***' Cannot find real ${0##*/} command 
    exit 1
fi

## root has no business installing things here!!
if [ $(id -u) -eq 0 ]; then
    echo 1>&2 '***' $(dirname $0) should not be in root\'s \$PATH
    echo 1>&2 '***' call '"'$DAISY_CHAIN ${pristinecmd[*]}'"' directly
    exit 1
fi

## Report
#  When we change something, note what the original command was in the
#  logs.
report()
{
	echo 1>&2 '***' install ${pristinecmd[*]}
	return
}

## locale suppression
#  $SUPPRESSLOCALEDIR is set in the pkgusr's environment.  It defaults
#  to `1' (on) which means: DO NOT install locale stuff.  To override
#  it set SUPPRESSLOCALEDIR=0 in the pkgusr's ~/.pkgusrrc.
#
#  For me, at least, the only package I turn off the suppression is
#  glibc, and that is only to satisfy glibc's test suite.
if [ ${SUPPRESSLOCALEDIR} -eq 1 ]; then
    case "${pristinecmd[-1]}" in
	(*/share/locale/*)
	echo 1>&2 '***' Suppressed locale installation for: ${pristinecmd[-1]}
	report
	exit 0
	;;
    esac
fi

## Directories
#  Only allow the creation of directories that don't already exist.
_dirs()
{
    local dir=${pristinecmd[-1]}

    if [ -d ${dir} ]; then
	report
	exit 0
    else
	cmdopts="$cmdopts -d"
    fi
    return
}

## Group
#  If $group is one of the groups we belong to, use it, otherwise set
#  -g to our currently active group and report it.
_group()
{
    local GRP_CHAIN=""
    local GRP_LIST

    # GID or name?
    printf '%d' "$group" &>/dev/null
    if [ $? -eq 0 ]; then
	GRP_LIST=$(id -G)
    else
	GRP_LIST=$(id -Gn)
    fi

    for g in ${GRP_LIST}; do
	if [ $group == "$g" ]; then
	    GRP_CHAIN=$g
	    break
	fi
    done

    if [ -z "$GRP_CHAIN" ]; then
	report
	cmdopts="$cmdopts -g$(id -gn)"
    else
	cmdopts="$cmdopts -g$group"
    fi
    return
}

## Owner
#  Set -o to our username and report if it wasn't already our name.
_owner()
{
    local MYNAME

    # UID or name?
    printf '%d' "$owner" &>/dev/null
    if [ $? -eq 0 ]; then
	MYNAME=$(id -u)
    else
	MYNAME=$(id -un)
    fi

    if [ $owner != "$MYNAME" ]; then
	report
    fi
    cmdopts="$cmdopts -o$(id -un)"
    return
}

## Mode
#  Remove any nasty bits like setuid, setgid, sticky.
_perms()
{
    local tperm=${perm}

    printf '%o' "0${tperm}" &>/dev/null
    if [ $? -ne 0 ]; then
	tperm=${tperm//[st]/}
    else
	if [ ${tperm} -gt 777 ]; then
	    tperm=${tperm/?/}
	fi
    fi
    # Did we change anything?
    if [ "${tperm}" != "${perm}" ]; then
	report
	cmdopts="$cmdopts -m$tperm"
    else
	cmdopts="$cmdopts -m$perm"
    fi
    return
}

## Parse the command line.
#   All we really care about here is -d, -o, -g, and -m.  -c is
#   silently dropped.  Unrecognised options cause the script to exit
#   with a non-zero return code.
#
#   Any other legal options get passed on without alteration.
#
# NOTE: The following long options will most likely cause this script
#       to fail (hopefully they are obscure enough to not worry about)
#
#         --preserve-timestamps (short opt '-p' is OK)
#         --strip-program
#         --target-directory (short opt '-t' is OK)
#         --no-target-directory (short opt '-T' is OK)
#         --preserve-context
#
args=bcCdDpsTvg:m:o:S:t:Z:-:
while getopts $args opts; do
    case $opts in
	(-)
	## Long options
	case $OPTARG in
	    # Passed through unaltered.
	    (backup*|compare|strip|suffix*|verbose|context*|version|help)
	        cmdopts="$cmdopts --${OPTARG}" ;;
	    # The options we care about.
	    (directory) _dirs ;;
	    (group*) group=${OPTARG/group[=[:space:]]/}; _group ;;
	    (mode*) perm=${OPTARG/mode[=[:space:]]/}; _perms ;;
	    (owner*) owner=${OPTARG/owner[=[:space:]]/}; _owner ;;
	    # Anything else errors out.
	    (*) echo 1>&2 '***' Illegal option -- ${OPTARG}
	        exit 1
		;;
	esac
	;;
	## Short options
	# Passed through unaltered.
	(b|C|D|p|s|T|v|S|t|Z) cmdopts="$cmdopts -${opts}${OPTARG}" ;;
	# Dropped.
	(c) ;;
	# The options we care about.
	(d) _dirs ;;
	(g) group=${OPTARG}; _group ;;
	(m) perm=${OPTARG}; _perms ;;
	(o) owner=${OPTARG}; _owner ;;
	# Illegal options.
	(*) exit 1 ;;
    esac
done
shift $(( $OPTIND - 1 ))

# We've done all we can, now lets run install
$DAISY_CHAIN ${cmdopts} $@ || exit $?
exit 0

### End install

# Local variables:
# sh-basic-offset: 4
# End: