1#!/bin/sh 2# Create a temporary directory, sort of like mktemp -d does. 3 4# Copyright (C) 2007 Red Hat, Inc. All rights reserved. 5# 6# This copyrighted material is made available to anyone wishing to use, 7# modify, copy, or redistribute it subject to the terms and conditions 8# of the GNU General Public License v.2. 9# 10# You should have received a copy of the GNU General Public License 11# along with this program; if not, write to the Free Software Foundation, 12# Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 13 14# Written by Jim Meyering. 15 16# Usage: mkdtemp /tmp phoey.XXXXXXXXXX 17 18# First, try to use the mktemp program. 19# Failing that, we'll roll our own mktemp-like function: 20# - try to get random bytes from /dev/urandom 21# - failing that, generate output from a combination of quickly-varying 22# sources and gzip. Ignore non-varying gzip header, and extract 23# "random" bits from there. 24# - given those bits, map to file-name bytes using tr, and try to create 25# the desired directory. 26# - make only $MAX_TRIES attempts 27 28ME=$(basename "$0") 29die() { echo >&2 "$ME: $@"; exit 1; } 30 31MAX_TRIES=4 32 33rand_bytes() 34{ 35 n=$1 36 37 chars=abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789 38 39 dev_rand=/dev/urandom 40 if test -r "$dev_rand"; then 41 # Note: 256-length($chars) == 194; 3 copies of $chars is 186 + 8 = 194. 42 head -c$n "$dev_rand" | tr -c $chars 01234567$chars$chars$chars 43 return 44 fi 45 46 cmds='date; date +%N; free; who -a; w; ps auxww; ps ef; netstat -n' 47 data=$( (eval "$cmds") 2>&1 | gzip ) 48 49 n_plus_50=$(expr $n + 50) 50 51 # Ensure that $data has length at least 50+$n 52 while :; do 53 len=$(echo "$data"|wc -c) 54 test $n_plus_50 -le $len && break; 55 data=$( (echo "$data"; eval "$cmds") 2>&1 | gzip ) 56 done 57 58 echo "$data" \ 59 | dd bs=1 skip=50 count=$n 2>/dev/null \ 60 | tr -c $chars 01234567$chars$chars$chars 61} 62 63mkdtemp() 64{ 65 case $# in 66 2);; 67 *) die "Usage: $ME DIR TEMPLATE";; 68 esac 69 70 destdir=$1 71 template=$2 72 73 case $template in 74 *XXXX) ;; 75 *) die "invalid template: $template (must have a suffix of at least 4 X's)";; 76 esac 77 78 fail=0 79 80 # First, try to use mktemp. 81 d=$(env -u TMPDIR mktemp -d -t -p "$destdir" "$template" 2>/dev/null) \ 82 || fail=1 83 84 # The resulting name must be in the specified directory. 85 case $d in "$destdir"*);; *) fail=1;; esac 86 87 # It must have created the directory. 88 test -d "$d" || fail=1 89 90 # It must have 0700 permissions. 91 perms=$(ls -dgo "$d" 2>/dev/null) || fail=1 92 case $perms in drwx------*) ;; *) fail=1;; esac 93 94 test $fail = 0 && { 95 echo "$d" 96 return 97 } 98 99 # If we reach this point, we'll have to create a directory manually. 100 101 # Get a copy of the template without its suffix of X's. 102 base_template=$(echo "$template"|sed 's/XX*$//') 103 104 # Calculate how many X's we've just removed. 105 nx=$(expr length "$template" - length "$base_template") 106 107 err= 108 i=1 109 while :; do 110 X=$(rand_bytes $nx) 111 candidate_dir="$destdir/$base_template$X" 112 err=$(mkdir -m 0700 "$candidate_dir" 2>&1) \ 113 && { echo "$candidate_dir"; return; } 114 test $MAX_TRIES -le $i && break; 115 i=$(expr $i + 1) 116 done 117 die "$err" 118} 119 120mkdtemp "$@" 121