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// Copyright 2015 The Bazel Authors. All rights reserved.
//
// 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 com.google.devtools.build.lib.bazel.repository;
import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.Optional;
import com.google.common.base.Preconditions;
import com.google.devtools.build.lib.bazel.repository.DecompressorValue.Decompressor;
import com.google.devtools.build.lib.rules.repository.RepositoryFunction.RepositoryFunctionException;
import com.google.devtools.build.lib.vfs.FileSystemUtils;
import com.google.devtools.build.lib.vfs.Path;
import com.google.devtools.build.lib.vfs.PathFragment;
import com.google.devtools.build.skyframe.SkyFunctionException.Transience;
import com.google.devtools.build.zip.ZipFileEntry;
import com.google.devtools.build.zip.ZipReader;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.nio.charset.Charset;
import java.nio.file.Files;
import java.nio.file.StandardCopyOption;
import java.util.Collection;
import javax.annotation.Nullable;
/**
* Creates a repository by decompressing a zip file.
*/
public class ZipDecompressor implements Decompressor {
public static final Decompressor INSTANCE = new ZipDecompressor();
private static final long MAX_PATH_LENGTH = 256;
private ZipDecompressor() {
}
private static final int S_IFDIR = 040000;
private static final int S_IFREG = 0100000;
private static final int S_IFLNK = 0120000;
private static final int EXECUTABLE_MASK = 0755;
@VisibleForTesting
static final int WINDOWS_DIRECTORY = 0x10;
@VisibleForTesting
static final int WINDOWS_FILE = 0x20;
/**
* This unzips the zip file to a sibling directory of {@link DecompressorDescriptor#archivePath}.
* The zip file is expected to have the WORKSPACE file at the top level, e.g.:
*
* <pre>
* $ unzip -lf some-repo.zip
* Archive: ../repo.zip
* Length Date Time Name
* --------- ---------- ----- ----
* 0 2014-11-20 15:50 WORKSPACE
* 0 2014-11-20 16:10 foo/
* 236 2014-11-20 15:52 foo/BUILD
* ...
* </pre>
*/
@Override
@Nullable
public Path decompress(DecompressorDescriptor descriptor) throws RepositoryFunctionException {
Path destinationDirectory = descriptor.archivePath().getParentDirectory();
Optional<String> prefix = descriptor.prefix();
boolean foundPrefix = false;
try (ZipReader reader = new ZipReader(descriptor.archivePath().getPathFile())) {
Collection<ZipFileEntry> entries = reader.entries();
for (ZipFileEntry entry : entries) {
StripPrefixedPath entryPath = StripPrefixedPath.maybeDeprefix(entry.getName(), prefix);
foundPrefix = foundPrefix || entryPath.foundPrefix();
if (entryPath.skip()) {
continue;
}
extractZipEntry(reader, entry, destinationDirectory, entryPath.getPathFragment());
}
} catch (IOException e) {
throw new RepositoryFunctionException(new IOException(
String.format("Error extracting %s to %s: %s",
descriptor.archivePath(), destinationDirectory, e.getMessage())),
Transience.TRANSIENT);
}
if (prefix.isPresent() && !foundPrefix) {
throw new RepositoryFunctionException(
new IOException("Prefix " + prefix.get() + " was given, but not found in the zip"),
Transience.PERSISTENT);
}
return destinationDirectory;
}
private static void extractZipEntry(
ZipReader reader,
ZipFileEntry entry,
Path destinationDirectory,
PathFragment strippedRelativePath)
throws IOException {
if (strippedRelativePath.isAbsolute()) {
throw new IOException(
String.format(
"Failed to extract %s, zipped paths cannot be absolute", strippedRelativePath));
}
Path outputPath = destinationDirectory.getRelative(strippedRelativePath);
int permissions = getPermissions(entry.getExternalAttributes(), entry.getName());
FileSystemUtils.createDirectoryAndParents(outputPath.getParentDirectory());
boolean isDirectory = (permissions & S_IFDIR) == S_IFDIR;
boolean isSymlink = (permissions & S_IFLNK) == S_IFLNK;
if (isDirectory) {
FileSystemUtils.createDirectoryAndParents(outputPath);
} else if (isSymlink) {
Preconditions.checkState(entry.getSize() < MAX_PATH_LENGTH);
byte[] buffer = new byte[(int) entry.getSize()];
// For symlinks, the "compressed data" is actually the target name.
int read = reader.getInputStream(entry).read(buffer);
Preconditions.checkState(read == buffer.length);
PathFragment target = PathFragment.create(new String(buffer, Charset.defaultCharset()))
.normalize();
if (!target.isNormalized()) {
PathFragment pointsTo =
PathFragment.create(strippedRelativePath.getParentDirectory(), target).normalize();
if (!pointsTo.isNormalized()) {
throw new IOException("Zip entries cannot refer to files outside of their directory: "
+ reader.getFilename() + " has a symlink " + strippedRelativePath + " pointing to "
+ target);
}
}
if (target.isAbsolute()) {
target = target.relativeTo(PathFragment.ROOT_DIR);
target = destinationDirectory.getRelative(target).asFragment();
}
outputPath.createSymbolicLink(target);
} else {
// TODO(kchodorow): should be able to be removed when issue #236 is resolved, but for now
// this delete+rewrite is required or the build will error out if outputPath exists here.
// The zip file is not re-unzipped when the WORKSPACE file is changed (because it is assumed
// to be immutable) but is on server restart (which is a bug).
File outputFile = outputPath.getPathFile();
try (InputStream input = reader.getInputStream(entry)) {
Files.copy(input, outputFile.toPath(), StandardCopyOption.REPLACE_EXISTING);
}
outputPath.chmod(permissions);
outputPath.setLastModifiedTime(entry.getTime());
}
}
@VisibleForTesting
static int getPermissions(int permissions, String path) throws IOException {
// Sometimes zip files list directories as being "regular" executable files (i.e., 0100755).
// I'm looking at you, Go AppEngine SDK 1.9.37 (see #1263 for details).
if (path.endsWith("/")) {
return S_IFDIR | EXECUTABLE_MASK;
}
// Posix permissions are in the high-order 2 bytes of the external attributes. After this
// operation, permissions holds 0100755 (or 040755 for directories).
int shiftedPermissions = permissions >>> 16;
if (shiftedPermissions != 0) {
return shiftedPermissions;
}
// If this was zipped up on FAT, it won't have posix permissions set. Instead, this
// checks if extra attributes is set to 0 for files. From
// https://github.com/miloyip/rapidjson/archive/v1.0.2.zip, it looks like executables end up
// with "normal" (posix) permissions (oddly), so they'll be handled above.
int windowsPermission = permissions & 0xff;
if ((windowsPermission & WINDOWS_DIRECTORY) == WINDOWS_DIRECTORY) {
// Directory.
return S_IFDIR | EXECUTABLE_MASK;
} else if (permissions == 0 || (windowsPermission & WINDOWS_FILE) == WINDOWS_FILE) {
// File.
return S_IFREG | EXECUTABLE_MASK;
}
// No idea.
throw new IOException("Unrecognized file mode for " + path + ": 0x"
+ Integer.toHexString(permissions));
}
}
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