#!/bin/bash

 # Copyright (c) 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!

 

 #The following list should contain the mount points of all filesystems

 #that are to be scanned as a space-separated list within parentheses. 

 #/ will usually be in this list and if you have /usr

 #on a separate partition, it will also be in this list. Other non-special

 #filesystems where package users could own files should also be put in this

 #list.

 #Mount points whose filesystems are special, such as procfs or sysfs must

 #not be in this list. While a simple find on those special filesystems should 

 #be harmless, operations such as "-exec grep something" are NOT SAFE and may 

 #have HARMFUL SIDE-EFFECTS, especially when performed as root. 

 fs_to_scan=(/)

 

 #Files with a path prefix found in the following list are ignored.

 #This list will usually contain the parent directory of your package users'

 #home directories, because normally you don't want to scan those. You can

 #also add other directories that will never contain package user files, such

 #as /home. This reduces scan time.

 #NOTE: The LFS-6.0 book uses a ramfs mounted on /dev and with that setup

 #/dev does not need to be in the prune list. But since there is no requirement

 #that /dev have its on filesystem it's better to prune it explicitly.

 prune_prefixes=(/home /usr/src /dev /tools) #NO TRAILING SLASHES!!!!

 

 if [ $# -lt 1 -o "$1" = "--help" ]; then

   echo 1>&2

   echo 1>&2 'USAGE: '"${0##*/}"' <user_or_group_name> [<find-commands>]'

   echo 1>&2

   echo 1>&2 '  If <find-commands> contains no action other than -prune, -print will be'

   echo 1>&2 '    executed for all matching files.'

   echo 1>&2 '  Entries will be matched if group and/or user equals <user_or_group_name>'

   echo 1>&2 '    (numeric UID/GID allowed).'

   echo 1>&2 '  All matching entries will be acted on, including device special files, so'

   echo 1>&2 '    you should be extra careful with the <find-commands> you provide!'

   echo 1>&2

   exit 1

 fi

 

 #suppress ugly debug output from shell

 trap ':' SIGPIPE

 

 ugname="$1"

 shift 1  #remove user_or_group_name from argument list

 

 # Recent versions of find issue a warning if "-depth" is listed after a

 # non-option argument. To prevent this warning if -depth is passed to

 # this script, we pick up the "-depth" argument here to move it to the

 # front later on.

 depth=""

 if [ "_$1" = "_-depth" ]; then

   depth=-depth

   shift 1

 fi

 

 ugmatcher=(-false)

 #test if find accepts ugname as a user, and append to ugmatcher if it does

 if find / -maxdepth 0 -user "$ugname" >/dev/null 2>&1 ; then

   ugmatcher[${#ugmatcher[@]}]="-or"

   ugmatcher[${#ugmatcher[@]}]="-user"

   ugmatcher[${#ugmatcher[@]}]="$ugname"

 fi

 #test if find accepts ugname as a group, and append to ugmatcher if it does

 if find / -maxdepth 0 -group "$ugname" >/dev/null 2>&1 ; then

   ugmatcher[${#ugmatcher[@]}]="-or"

   ugmatcher[${#ugmatcher[@]}]="-group"

   ugmatcher[${#ugmatcher[@]}]="$ugname"

 fi

 

 #if find accepted ugname as neither user nor group, then exit

 if [ "${#ugmatcher[@]}" = 1 ]; then

   echo 1>&2 'find does not accept `'"$ugname'"' as group or user name'

   exit 1

 fi

 

 #construct find commands that match the prune_prefixes. Each prefix will be

 #matched as -path <prefix> -or -path <prefix>/*

 #so that the directory itself and all subdirectories are matched.

 y=(\( -false)

 for ((i=0; $i<${#prune_prefixes[@]}; i=$i+1)) 

 do

   y[${#y[@]}]='-or'

   y[${#y[@]}]=-path

   y[${#y[@]}]="${prune_prefixes[$i]}"

   y[${#y[@]}]='-or'

   y[${#y[@]}]=-path

   y[${#y[@]}]="${prune_prefixes[$i]}/*"

 done

 y[${#y[@]}]=')'

 

 #In the following find command, the part

 # -not ( ( "${y[@]}" -prune ) -or "${y[@]}" )

 #is responsible for preventing the files that match prune_prefixes from

 #being processed. The 2nd "${y[@]}" may seem redundant, but it isn't, because

 #-prune has no effect and is always false when -depth is used.

 #The -true before "$@" ensures that -depth can be passed as only parameter.

 find "${fs_to_scan[@]}" $depth -xdev -noleaf \

      -not \( \( "${y[@]}" -prune \) -or "${y[@]}" \) \

      -and \( "${ugmatcher[@]}" \) -and \( -true "$@" \)