mirror of
https://github.com/apple/container.git
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J Logan
62 lines
2.3 KiB
Swift
62 lines
2.3 KiB
Swift
//===----------------------------------------------------------------------===//
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// Copyright © 2025 Apple Inc. and the container 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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import ContainerizationOS
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// For a lot of programs, they don't install their own signal handlers for
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// SIGINT/SIGTERM which poses a somewhat fun problem for containers. Because
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// they're pid 1 (doesn't matter that it isn't in the "root" pid namespace)
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// the default actions for SIGINT and SIGTERM now are nops. So this type gives
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// us an opportunity to set a threshold for a certain number of signals received
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// so we can have an escape hatch for users to escape their horrific mistake
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// of cat'ing /dev/urandom by exit(1)'ing :)
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public struct SignalThreshold {
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private let threshold: Int
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private let signals: [Int32]
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private var t: Task<(), Never>?
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public init(
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threshold: Int,
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signals: [Int32],
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) {
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self.threshold = threshold
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self.signals = signals
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}
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// Start kicks off the signal watching. The passed in handler will
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// run only once upon passing the threshold number passed in the constructor.
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mutating public func start(handler: @Sendable @escaping () -> Void) {
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let signals = self.signals
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let threshold = self.threshold
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self.t = Task {
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var received = 0
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let signalHandler = AsyncSignalHandler.create(notify: signals)
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for await _ in signalHandler.signals {
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received += 1
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if received == threshold {
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handler()
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signalHandler.cancel()
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return
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}
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}
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}
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}
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public func stop() {
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self.t?.cancel()
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}
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}
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