oid_registry: allow arbitrary size OIDs

The current OID registry parser uses 64 bit arithmetic which limits us to
supporting 64 bit or smaller OIDs.  This isn't usually a problem except
that it prevents us from representing the 2.25.  prefix OIDs which are the
OID representation of UUIDs and have a 128 bit number following the
prefix.  Rather than import not often used perl arithmetic modules,
replace the current perl 64 bit arithmetic with a callout to bc, which is
arbitrary precision, for decimal to base 2 conversion, then do pure string
operations on the base 2 number.

[James.Bottomley@HansenPartnership.com: tidy up perl with better my placement also set bc to arbitrary size]
Link: https://lkml.kernel.org/r/dbc90c344c691ed988640a28367ff895b5ef2604.camel@HansenPartnership.com
Link: https://lkml.kernel.org/r/833c858cd74533203b43180208734b84f1137af0.camel@HansenPartnership.com
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Blaise Boscaccy <bboscaccy@linux.microsoft.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/lib/build_OID_registry b/lib/build_OID_registry
index 8267e8d71338b06dd7354f6be7b9577b836b07da..30493ac190c0c599aecf3cfa6808c42364cbc80e 100755 (executable)
--- a/lib/build_OID_registry
+++ b/lib/build_OID_registry
@@ -60,10 +60,12 @@ for (my $i = 0; $i <= $#names; $i++) {
     # Determine the encoded length of this OID
     my $size = $#components;
     for (my $loop = 2; $loop <= $#components; $loop++) {
-       my $c = $components[$loop];
+       $ENV{'BC_LINE_LENGTH'} = "0";
+       my $c = `echo "ibase=10; obase=2; $components[$loop]" | bc`;
+       chomp($c);
 
        # We will base128 encode the number
-       my $tmp = ($c == 0) ? 0 : int(log($c)/log(2));
+       my $tmp = length($c) - 1;
        $tmp = int($tmp / 7);
        $size += $tmp;
     }
@@ -100,16 +102,24 @@ for (my $i = 0; $i <= $#names; $i++) {
     push @octets, $components[0] * 40 + $components[1];
 
     for (my $loop = 2; $loop <= $#components; $loop++) {
-       my $c = $components[$loop];
+       # get the base 2 representation of the component
+       $ENV{'BC_LINE_LENGTH'} = "0";
+       my $c = `echo "ibase=10; obase=2; $components[$loop]" | bc`;
+       chomp($c);
 
-       # Base128 encode the number
-       my $tmp = ($c == 0) ? 0 : int(log($c)/log(2));
+       my $tmp = length($c) - 1;
        $tmp = int($tmp / 7);
 
-       for (; $tmp > 0; $tmp--) {
-           push @octets, (($c >> $tmp * 7) & 0x7f) | 0x80;
+       # zero pad upto length multiple of 7
+       $c = substr("0000000", 0, ($tmp + 1) * 7 - length($c)).$c;
+
+       # Base128 encode the number
+       for (my $j = 0; $j < $tmp; $j++) {
+           my $b = oct("0b".substr($c, $j * 7, 7));
+
+           push @octets, $b | 0x80;
        }
-       push @octets, $c & 0x7f;
+       push @octets, oct("0b".substr($c, $tmp * 7, 7));
     }
 
     push @encoded_oids, \@octets;