wehub-resource-sync
109 lines
3.4 KiB
Swift
109 lines
3.4 KiB
Swift
//===----------------------------------------------------------------------===//
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// Copyright © 2026 Apple Inc. and the Containerization project authors.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// https://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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//===----------------------------------------------------------------------===//
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#if os(Linux)
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import ContainerizationOS
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import Foundation
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import Synchronization
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struct ProcessSubscription: Sendable {
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fileprivate let id: UUID
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}
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/// Protocol for running commands and waiting for their exit
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protocol CommandRunner: Sendable {
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func start(_ cmd: inout Command) throws -> ProcessSubscription
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func wait(_ cmd: Command, subscription: ProcessSubscription) async throws -> Int32
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}
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struct DirectCommandRunner: CommandRunner {
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func start(_ cmd: inout Command) throws -> ProcessSubscription {
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try cmd.start()
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return ProcessSubscription(id: UUID())
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}
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func wait(_ cmd: Command, subscription: ProcessSubscription) async throws -> Int32 {
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var rus = rusage()
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var ws = Int32()
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let result = wait4(cmd.pid, &ws, 0, &rus)
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guard result == cmd.pid else {
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throw POSIXError(.init(rawValue: errno)!)
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}
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return Command.toExitStatus(ws)
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}
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}
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final class ReaperCommandRunner: CommandRunner, Sendable {
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private struct Subscriber {
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let continuation: AsyncStream<(pid: pid_t, status: Int32)>.Continuation
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let stream: AsyncStream<(pid: pid_t, status: Int32)>
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}
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private let subscribers: Mutex<[UUID: Subscriber]> = Mutex([:])
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func start(_ cmd: inout Command) throws -> ProcessSubscription {
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// Subscribe before starting to avoid missing fast exits
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let id = UUID()
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let (stream, continuation) = AsyncStream<(pid: pid_t, status: Int32)>.makeStream()
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subscribers.withLock { subscribers in
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subscribers[id] = Subscriber(continuation: continuation, stream: stream)
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}
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try cmd.start()
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return ProcessSubscription(id: id)
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}
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func wait(_ cmd: Command, subscription: ProcessSubscription) async throws -> Int32 {
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let pid = cmd.pid
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let id = subscription.id
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defer {
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subscribers.withLock { subscribers in
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subscribers[id]?.continuation.finish()
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subscribers.removeValue(forKey: id)
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}
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}
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// Get the stream from the subscriber
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guard let stream = subscribers.withLock({ $0[id]?.stream }) else {
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throw POSIXError(.ECHILD)
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}
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for await (exitPid, status) in stream {
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if exitPid == pid {
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return status
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}
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}
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throw POSIXError(.ECHILD)
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}
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/// Broadcast exit to all subscribers
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func notifyExit(pid: pid_t, status: Int32) {
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subscribers.withLock { subscribers in
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for subscriber in subscribers.values {
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subscriber.continuation.yield((pid, status))
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}
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}
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}
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}
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#endif
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