add base64 decode function

xCAT-server/share/xcat/install/scripts/pre.ubuntu.ppc64

@@ -120,7 +120,77 @@ chmod 755 /tmp/foo.sh
 
 /tmp/foo.sh >/tmp/foo.log 2>&1 &
 
+# This function is intend to be used in the busybox sh inside debian-installer
+# initrd image. Due to the limitation of the commands can be used in such an
+# environment, there are some strange parts is this script.
+#
+# Command printf is the only external command to be called.
+#
+# This function can run under bash as well, but will failed under bash invoked
+# with the name sh.
+#
+# Usage:
+#
+# base64encode <input_file >out_file
+#
 
+base64decode()
+{
+	h0="0";  h1="1";  h2="2";  h3="3";  h4="4";  h5="5";  h6="6";  h7="7";
+	h8="8";  h9="9"; h10="A"; h11="B"; h12="C"; h13="D"; h14="E"; h15="F";
+
+	while :
+	do
+		i=0
+		while [ "$i" -lt 4 ]
+		do
+			read -n 1 c || return
+	
+			case "${c}" in
+			"A") d=0  ;; "B") d=1  ;; "C") d=2  ;; "D") d=3  ;;
+			"E") d=4  ;; "F") d=5  ;; "G") d=6  ;; "H") d=7  ;;
+			"I") d=8  ;; "J") d=9  ;; "K") d=10 ;; "L") d=11 ;;
+			"M") d=12 ;; "N") d=13 ;; "O") d=14 ;; "P") d=15 ;;
+			"Q") d=16 ;; "R") d=17 ;; "S") d=18 ;; "T") d=19 ;;
+			"U") d=20 ;; "V") d=21 ;; "W") d=22 ;; "X") d=23 ;;
+			"Y") d=24 ;; "Z") d=25 ;; "a") d=26 ;; "b") d=27 ;;
+			"c") d=28 ;; "d") d=29 ;; "e") d=30 ;; "f") d=31 ;;
+			"g") d=32 ;; "h") d=33 ;; "i") d=34 ;; "j") d=35 ;;
+			"k") d=36 ;; "l") d=37 ;; "m") d=38 ;; "n") d=39 ;;
+			"o") d=40 ;; "p") d=41 ;; "q") d=42 ;; "r") d=43 ;;
+			"s") d=44 ;; "t") d=45 ;; "u") d=46 ;; "v") d=47 ;;
+			"w") d=48 ;; "x") d=49 ;; "y") d=50 ;; "z") d=51 ;;
+			"0") d=52 ;; "1") d=53 ;; "2") d=54 ;; "3") d=55 ;;
+			"4") d=56 ;; "5") d=57 ;; "6") d=58 ;; "7") d=59 ;;
+			"8") d=60 ;; "9") d=61 ;; "+") d=62 ;; "/") d=63 ;;
+			"=") d=0  ;;
+			*) continue ;;
+			esac
+	
+			eval "a${i}=${c}"
+			eval "b${i}=${d}"
+
+			i=$(( i + 1 ))
+		done
+	
+		o0=$(( ((b0 << 2) | (b1 >> 4)) & 0xff ))
+		o1=$(( ((b1 << 4) | (b2 >> 2)) & 0xff ))
+		o2=$(( ((b2 << 6) | b3) & 0xff ))
+	
+		[ "${a2}" == "=" ] &&
+			eval "printf \"\\x\${h$(( o0 / 16 ))}\${h$(( o0 % 16
+				))}\"" &&
+			return
+		[ "${a3}" == "=" ] &&
+			eval "printf \"\\x\${h$(( o0 / 16 ))}\${h$(( o0 % 16
+				))}\\x\${h$(( o1 / 16 ))}\${h$(( o1 % 16
+				))}\"" &&
+			return
+		eval "printf \"\\x\${h$(( o0 / 16 ))}\${h$(( o0 % 16
+			))}\\x\${h$(( o1 / 16 ))}\${h$(( o1 % 16
+			))}\\x\${h$(( o2 / 16 ))}\${h$(( o2 % 16 ))}\""
+	done
+}
 
 if [ -d /sys/firmware/efi ]; then
     echo "ubuntu-efi ::" > /tmp/partitioning