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Merge "Store entry alignment information in APK."

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Alex Klyubin 2016-05-27 19:57:11 +00:00 committed by Gerrit Code Review
commit 85f004c6c5
1 changed files with 42 additions and 16 deletions
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58
tools/signapk/src/com/android/signapk/SignApk.java
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@ -52,6 +52,7 @@ import java.io.OutputStream;
import java.io.PrintStream;
import java.lang.reflect.Constructor;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.security.DigestOutputStream;
import java.security.GeneralSecurityException;
import java.security.InvalidKeyException;
@ -119,6 +120,19 @@ class SignApk {
private static final String OTACERT_NAME = "META-INF/com/android/otacert";
/**
* Extensible data block/field header ID used for storing information about alignment of
* uncompressed entries as well as for aligning the entries's data. See ZIP appnote.txt section
* 4.5 Extensible data fields.
*/
private static final short ALIGNMENT_ZIP_EXTRA_DATA_FIELD_HEADER_ID = (short) 0xd935;
/**
* Minimum size (in bytes) of the extensible data block/field used for alignment of uncompressed
* entries.
*/
private static final short ALIGNMENT_ZIP_EXTRA_DATA_FIELD_MIN_SIZE_BYTES = 6;
// bitmasks for which hash algorithms we need the manifest to include.
private static final int USE_SHA1 = 1;
private static final int USE_SHA256 = 2;
@ -588,28 +602,40 @@ class SignApk {
outEntry.setComment(null);
outEntry.setExtra(null);
// 'offset' is the offset into the file at which we expect
// the file data to begin. This is the value we need to
// make a multiple of 'alignement'.
int alignment = getStoredEntryDataAlignment(name, defaultAlignment);
// Alignment of the entry's data is achieved by adding a data block to the entry's Local
// File Header extra field. The data block contains information about the alignment
// value and the necessary padding bytes (0x00) to achieve the alignment. This works
// because the entry's data will be located immediately after the extra field.
// See ZIP APPNOTE.txt section "4.5 Extensible data fields" for details about the format
// of the extra field.
// 'offset' is the offset into the file at which we expect the entry's data to begin.
// This is the value we need to make a multiple of 'alignment'.
offset += JarFile.LOCHDR + outEntry.getName().length();
if (firstEntry) {
// The first entry in a jar file has an extra field of
// four bytes that you can't get rid of; any extra
// data you specify in the JarEntry is appended to
// these forced four bytes. This is JAR_MAGIC in
// JarOutputStream; the bytes are 0xfeca0000.
// The first entry in a jar file has an extra field of four bytes that you can't get
// rid of; any extra data you specify in the JarEntry is appended to these forced
// four bytes. This is JAR_MAGIC in JarOutputStream; the bytes are 0xfeca0000.
// See http://bugs.java.com/bugdatabase/view_bug.do?bug_id=6808540
// and http://bugs.java.com/bugdatabase/view_bug.do?bug_id=4138619.
offset += 4;
firstEntry = false;
}
int alignment = getStoredEntryDataAlignment(name, defaultAlignment);
if (alignment > 0 && (offset % alignment != 0)) {
// Set the "extra data" of the entry to between 1 and
// alignment-1 bytes, to make the file data begin at
// an aligned offset.
int needed = alignment - (int)(offset % alignment);
outEntry.setExtra(new byte[needed]);
offset += needed;
int extraPaddingSizeBytes = 0;
if (alignment > 0) {
long paddingStartOffset = offset + ALIGNMENT_ZIP_EXTRA_DATA_FIELD_MIN_SIZE_BYTES;
extraPaddingSizeBytes = alignment - (int) (paddingStartOffset % alignment);
}
byte[] extra =
new byte[ALIGNMENT_ZIP_EXTRA_DATA_FIELD_MIN_SIZE_BYTES + extraPaddingSizeBytes];
ByteBuffer extraBuf = ByteBuffer.wrap(extra);
extraBuf.order(ByteOrder.LITTLE_ENDIAN);
extraBuf.putShort(ALIGNMENT_ZIP_EXTRA_DATA_FIELD_HEADER_ID); // Header ID
extraBuf.putShort((short) (2 + extraPaddingSizeBytes)); // Data Size
extraBuf.putShort((short) alignment);
outEntry.setExtra(extra);
offset += extra.length;
out.putNextEntry(outEntry);