github.com/SagerNet/gvisor@v0.0.0-20210707092255-7731c139d75c/tools/checklocks/test/closures.go (about)

     1  // Copyright 2020 The gVisor Authors.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package test
    16  
    17  func testClosureInvalid(tc *oneGuardStruct) {
    18  	// This is expected to fail.
    19  	callClosure(func() {
    20  		tc.guardedField = 1 // +checklocksfail
    21  	})
    22  }
    23  
    24  func testClosureUnsupported(tc *oneGuardStruct) {
    25  	// Locked outside the closure, so may or may not be valid. This cannot
    26  	// be handled and we should explicitly fail. This can't be handled
    27  	// because of the call through callClosure, below, which means the
    28  	// closure will actually be passed as a value somewhere.
    29  	tc.mu.Lock()
    30  	callClosure(func() {
    31  		tc.guardedField = 1 // +checklocksfail
    32  	})
    33  	tc.mu.Unlock()
    34  }
    35  
    36  func testClosureValid(tc *oneGuardStruct) {
    37  	// All locking happens within the closure. This should not present a
    38  	// problem for analysis.
    39  	callClosure(func() {
    40  		tc.mu.Lock()
    41  		tc.guardedField = 1
    42  		tc.mu.Unlock()
    43  	})
    44  }
    45  
    46  func testClosureInline(tc *oneGuardStruct) {
    47  	// If the closure is being dispatching inline only, then we should be
    48  	// able to analyze this call and give it a thumbs up.
    49  	tc.mu.Lock()
    50  	func() {
    51  		tc.guardedField = 1
    52  	}()
    53  	tc.mu.Unlock()
    54  }
    55  
    56  func testAnonymousInvalid(tc *oneGuardStruct) {
    57  	// Invalid, as per testClosureInvalid above.
    58  	callAnonymous(func(tc *oneGuardStruct) {
    59  		tc.guardedField = 1 // +checklocksfail
    60  	}, tc)
    61  }
    62  
    63  func testAnonymousUnsupported(tc *oneGuardStruct) {
    64  	// Not supportable, as per testClosureUnsupported above.
    65  	tc.mu.Lock()
    66  	callAnonymous(func(tc *oneGuardStruct) {
    67  		tc.guardedField = 1 // +checklocksfail
    68  	}, tc)
    69  	tc.mu.Unlock()
    70  }
    71  
    72  func testAnonymousValid(tc *oneGuardStruct) {
    73  	// Valid, as per testClosureValid above.
    74  	callAnonymous(func(tc *oneGuardStruct) {
    75  		tc.mu.Lock()
    76  		tc.guardedField = 1
    77  		tc.mu.Unlock()
    78  	}, tc)
    79  }
    80  
    81  func testAnonymousInline(tc *oneGuardStruct) {
    82  	// Unlike the closure case, we are able to dynamically infer the set of
    83  	// preconditions for the function dispatch and assert that this is
    84  	// a valid call.
    85  	tc.mu.Lock()
    86  	func(tc *oneGuardStruct) {
    87  		tc.guardedField = 1
    88  	}(tc)
    89  	tc.mu.Unlock()
    90  }
    91  
    92  //go:noinline
    93  func callClosure(fn func()) {
    94  	fn()
    95  }
    96  
    97  //go:noinline
    98  func callAnonymous(fn func(*oneGuardStruct), tc *oneGuardStruct) {
    99  	fn(tc)
   100  }