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/*
* Copyright (c) SAS Institute, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package rpmutils
import (
"bytes"
"encoding/binary"
"errors"
"io"
"sort"
)
func writeTag(entries io.Writer, blobs *bytes.Buffer, tag int, e entry) error {
align, ok := typeAlign[e.dataType]
if ok {
n := blobs.Len() % align
if n != 0 {
if _, err := blobs.Write(make([]byte, align-n)); err != nil {
return err
}
}
}
ht := headerTag{
Tag: int32(tag),
DataType: int32(e.dataType),
Offset: int32(blobs.Len()),
Count: int32(e.count),
}
if err := binary.Write(entries, binary.BigEndian, &ht); err != nil {
return err
}
if _, err := blobs.Write(e.contents); err != nil {
return err
}
return nil
}
func writeRegion(entries io.Writer, blobs *bytes.Buffer, regionTag int, tagCount int) error {
// The data for a region tag is also in the format of a tag, and its offset
// points backwards to the first tag that's part of the region. This one
// covers the whole header.
regionValue := headerTag{
Tag: int32(regionTag),
DataType: RPM_BIN_TYPE,
Offset: int32(-16 * (1 + tagCount)),
Count: 16,
}
regionBuf := bytes.NewBuffer(make([]byte, 0, 16))
if err := binary.Write(regionBuf, binary.BigEndian, ®ionValue); err != nil {
return err
}
regionEntry := entry{dataType: RPM_BIN_TYPE, count: 16, contents: regionBuf.Bytes()}
return writeTag(entries, blobs, regionTag, regionEntry)
}
// WriteTo writes the header out, adding a region tag encompassing all the existing tags
func (hdr *rpmHeader) WriteTo(outfile io.Writer, regionTag int) error {
if regionTag != 0 && regionTag >= RPMTAG_HEADERREGIONS {
return errors.New("invalid region tag")
}
// sort tags
var keys []int
for k := range hdr.entries {
if k < RPMTAG_HEADERREGIONS {
// discard existing regions
continue
}
keys = append(keys, k)
}
sort.Ints(keys)
entries := bytes.NewBuffer(make([]byte, 0, 16*len(keys)))
blobs := bytes.NewBuffer(make([]byte, 0, hdr.origSize))
for _, k := range keys {
if k == regionTag {
continue
}
if err := writeTag(entries, blobs, k, hdr.entries[k]); err != nil {
return err
}
}
intro := headerIntro{
Magic: introMagic,
Reserved: 0,
Entries: uint32(len(keys) + 1),
Size: uint32(blobs.Len() + 16),
}
if err := binary.Write(outfile, binary.BigEndian, &intro); err != nil {
return err
}
if err := writeRegion(outfile, blobs, regionTag, len(keys)); err != nil {
return err
}
totalSize := 96 + blobs.Len() + entries.Len()
if _, err := io.Copy(outfile, entries); err != nil {
return err
}
if _, err := io.Copy(outfile, blobs); err != nil {
return err
}
if regionTag == RPMTAG_HEADERSIGNATURES {
alignment := totalSize % 8
if alignment != 0 {
if _, err := outfile.Write(make([]byte, 8-alignment)); err != nil {
return err
}
}
}
return nil
}
func (hdr *rpmHeader) size(regionTag int) (uint64, error) {
var sink byteCountSink
if err := hdr.WriteTo(&sink, regionTag); err != nil {
return 0, err
}
return uint64(sink), nil
}
type byteCountSink uint64
func (sink *byteCountSink) Write(data []byte) (int, error) {
*sink += byteCountSink(len(data))
return len(data), nil
}
// OriginalSignatureHeaderSize returns the size of the lead and signature header
// area as originally read from the file.
func (hdr *RpmHeader) OriginalSignatureHeaderSize() int {
return hdr.sigHeader.origSize + 96
}
// DumpSignatureHeader dumps the lead and signature header, optionally adding or
// changing padding to make it the same size as when it was originally read.
// Otherwise padding is removed to make it as small as possible.
//
// A RPM can be signed by removing the first OriginalSignatureHeaderSize() bytes
// of the file and replacing it with the result of DumpSignatureHeader().
func (hdr *RpmHeader) DumpSignatureHeader(sameSize bool) ([]byte, error) {
if len(hdr.lead) != 96 {
return nil, errors.New("invalid or missing RPM lead")
}
sigh := hdr.sigHeader
regionTag := RPMTAG_HEADERSIGNATURES
delete(sigh.entries, SIG_RESERVEDSPACE-_SIGHEADER_TAG_BASE)
if sameSize {
needed, err := sigh.size(regionTag)
if err != nil {
return nil, err
}
available := uint64(sigh.origSize)
if needed+16 <= available {
// Fill unused space with a RESERVEDSPACE tag
padding := make([]byte, available-needed-16)
sigh.entries[SIG_RESERVEDSPACE-_SIGHEADER_TAG_BASE] = entry{
dataType: RPM_BIN_TYPE,
count: int32(len(padding)),
contents: padding,
}
}
}
buf := new(bytes.Buffer)
buf.Write(hdr.lead)
if err := sigh.WriteTo(buf, regionTag); err != nil {
return nil, err
}
return buf.Bytes(), nil
}
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