github.com/bazelbuild/bazel-watcher@v0.25.2/internal/ibazel/process_group/process_group_windows.go (about)

     1  // Copyright 2018 The Bazel Authors. All rights reserved.
     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 process_group
    16  
    17  import (
    18  	"bytes"
    19  	"errors"
    20  	"os/exec"
    21  	"syscall"
    22  	"unsafe"
    23  )
    24  
    25  type winProcessGroup struct {
    26  	root   *exec.Cmd
    27  	job    syscall.Handle
    28  	ioport syscall.Handle
    29  }
    30  
    31  // Command creates a new ProcessGroup with a root command specified by the
    32  // arguments.
    33  func Command(name string, arg ...string) ProcessGroup {
    34  	root := exec.Command(name, arg...)
    35  	root.SysProcAttr = &syscall.SysProcAttr{CreationFlags: createSuspended}
    36  	return &winProcessGroup{root, syscall.Handle(0), syscall.Handle(0)}
    37  }
    38  
    39  func (pg *winProcessGroup) RootProcess() *exec.Cmd {
    40  	return pg.root
    41  }
    42  
    43  func (pg *winProcessGroup) Start() error {
    44  	if pg.job != 0 {
    45  		return errors.New("job already started")
    46  	}
    47  
    48  	err := pg.root.Start()
    49  	if err != nil {
    50  		return err
    51  	}
    52  
    53  	pg.job, err = createJobObject()
    54  	if err != nil {
    55  		return err
    56  	}
    57  
    58  	pg.ioport, err = syscall.CreateIoCompletionPort(syscall.InvalidHandle, syscall.Handle(0), 0, 1)
    59  	if err != nil {
    60  		return err
    61  	}
    62  
    63  	port := jobObjectAssociationCompletionPort{
    64  		CompletionKey:  pg.job,
    65  		CompletionPort: pg.ioport,
    66  	}
    67  
    68  	err = setInformationJobObject(pg.job, jobObjectAssociateCompletionPortInformation, uintptr(unsafe.Pointer(&port)), unsafe.Sizeof(port))
    69  	if err != nil {
    70  		return err
    71  	}
    72  
    73  	process, err := syscall.OpenProcess(processAllAccess, false, uint32(pg.root.Process.Pid))
    74  	if err != nil {
    75  		return err
    76  	}
    77  
    78  	err = assignProcessToJobObject(pg.job, process)
    79  	if err != nil {
    80  		return err
    81  	}
    82  
    83  	err = ntResumeProcess(process)
    84  	if err != nil {
    85  		return err
    86  	}
    87  
    88  	syscall.CloseHandle(process)
    89  
    90  	return nil
    91  }
    92  
    93  func (pg *winProcessGroup) Signal(signum syscall.Signal) error {
    94  	// signum is ignored on Windows as there's no support for signals
    95  	if pg.job == 0 {
    96  		return errors.New("job not started")
    97  	}
    98  
    99  	err := terminateJobObject(pg.job, 0)
   100  	if err != nil {
   101  		return err
   102  	}
   103  
   104  	return nil
   105  }
   106  
   107  func (pg *winProcessGroup) Wait() error {
   108  	var code uint32
   109  	var key uint32
   110  	var op *syscall.Overlapped
   111  
   112  	for {
   113  		err := syscall.GetQueuedCompletionStatus(pg.ioport, &code, &key, &op, syscall.INFINITE)
   114  		if err != nil {
   115  			return err
   116  		}
   117  		if key == uint32(pg.job) && code == jobObjectMsgActiveProcessZero {
   118  			break
   119  		}
   120  	}
   121  
   122  	return nil
   123  }
   124  
   125  func (pg *winProcessGroup) Close() error {
   126  	err := syscall.CloseHandle(pg.job)
   127  	if err != nil {
   128  		return err
   129  	}
   130  
   131  	err = syscall.CloseHandle(pg.ioport)
   132  	if err != nil {
   133  		return err
   134  	}
   135  
   136  	return nil
   137  }
   138  
   139  func (pg *winProcessGroup) Run() error {
   140  	if err := pg.Start(); err != nil {
   141  		return err
   142  	}
   143  	return pg.Wait()
   144  }
   145  
   146  func (pg *winProcessGroup) CombinedOutput() ([]byte, error) {
   147  	var b bytes.Buffer
   148  	pg.root.Stdout = &b
   149  	pg.root.Stderr = &b
   150  	err := pg.Run()
   151  	return b.Bytes(), err
   152  }