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// Copyright 2018 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.sandbox;
import static com.google.common.base.Preconditions.checkState;
import com.google.auto.value.AutoValue;
import com.google.devtools.build.lib.vfs.Path;
import com.google.devtools.build.lib.vfs.PathFragment;
import java.io.IOException;
import java.util.List;
/** Interface to interact with a sandboxfs instance. */
interface SandboxfsProcess {
/** Represents a single mapping within a sandboxfs file system. */
@AutoValue
abstract class Mapping {
/**
* Path within the sandbox. This looks like an absolute path but is treated as relative to the
* sandbox's root.
*/
abstract PathFragment path();
/** Absolute path from the host's file system to map into the sandbox. */
abstract PathFragment target();
/** Whether the mapped path is writable or not. */
abstract boolean writable();
/** Constructs a new mapping builder. */
static Builder builder() {
return new AutoValue_SandboxfsProcess_Mapping.Builder();
}
/** Builder for a single mapping within a sandboxfs file system. */
@AutoValue.Builder
abstract static class Builder {
/**
* Sets the path within the sandbox on which this mapping will appear. This looks like an
* absolute path but is treated as relative to the sandbox's root.
*
* @param path absolute path rooted at the sandbox's mount point
* @return the builder instance
*/
abstract Builder setPath(PathFragment path);
/**
* Sets the path to which this mapping refers. This is an absolute path into the host's
* file system.
*
* @param target absolute path into the host's file system
* @return the builder instance
*/
abstract Builder setTarget(PathFragment target);
/**
* Sets whether this mapping is writable or not when accessed via the sandbox.
*
* @param writable whether the mapping is writable or not
* @return the builder instance
*/
abstract Builder setWritable(boolean writable);
abstract Mapping autoBuild();
/**
* Constructs the mapping and validates field invariants.
*
* @return the constructed mapping.
*/
public Mapping build() {
Mapping mapping = autoBuild();
checkState(mapping.path().isAbsolute(), "Mapping specifications are supposed to be "
+ "absolute but %s is not", mapping.path());
checkState(mapping.target().isAbsolute(), "Mapping targets are supposed to be "
+ "absolute but %s is not", mapping.target());
return mapping;
}
}
}
/** Returns the path to the sandboxfs's mount point. */
Path getMountPoint();
/** Returns true if the sandboxfs process is still alive. */
boolean isAlive();
/**
* Unmounts and stops the sandboxfs process.
*
* <p>This function must be idempotent because there can be a race between explicit calls during
* regular execution and calls from shutdown hooks.
*/
void destroy();
/**
* Adds new mappings to the sandboxfs instance.
*
* @param mappings the collection of mappings to add, which must not have yet been previously
* mapped
* @throws IOException if sandboxfs cannot be reconfigured either because of an error in the
* configuration or because we failed to communicate with the subprocess
*/
void map(List<Mapping> mappings) throws IOException;
/**
* Removes a mapping from the sandboxfs instance.
*
* @param mapping the mapping to remove, which must have been previously mapped. This looks like
* an absolute path but is treated as relative to the sandbox's root.
* @throws IOException if sandboxfs cannot be reconfigured either because of an error in the
* configuration or because we failed to communicate with the subprocess
*/
void unmap(PathFragment mapping) throws IOException;
}