File size: 3,355 Bytes
e36aeda | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 | // Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
//go:build unix || (js && wasm) || wasip1
package os
import (
"errors"
"syscall"
"time"
)
const (
// Special values for Process.Pid.
pidUnset = 0
pidReleased = -1
)
func (p *Process) wait() (ps *ProcessState, err error) {
// Which type of Process do we have?
if p.handle != nil {
// pidfd
return p.pidfdWait()
} else {
// Regular PID
return p.pidWait()
}
}
func (p *Process) pidWait() (*ProcessState, error) {
// TODO(go.dev/issue/67642): When there are concurrent Wait calls, one
// may wait on the wrong process if the PID is reused after the
// completes its wait.
//
// Checking for statusDone here would not be a complete fix, as the PID
// could still be waited on and reused prior to blockUntilWaitable.
switch p.pidStatus() {
case statusReleased:
return nil, syscall.EINVAL
}
// If we can block until Wait4 will succeed immediately, do so.
ready, err := p.blockUntilWaitable()
if err != nil {
return nil, err
}
if ready {
// Mark the process done now, before the call to Wait4,
// so that Process.pidSignal will not send a signal.
p.doRelease(statusDone)
// Acquire a write lock on sigMu to wait for any
// active call to the signal method to complete.
p.sigMu.Lock()
p.sigMu.Unlock()
}
var (
status syscall.WaitStatus
rusage syscall.Rusage
)
pid1, err := ignoringEINTR2(func() (int, error) {
return syscall.Wait4(p.Pid, &status, 0, &rusage)
})
if err != nil {
return nil, NewSyscallError("wait", err)
}
p.doRelease(statusDone)
return &ProcessState{
pid: pid1,
status: status,
rusage: &rusage,
}, nil
}
func (p *Process) signal(sig Signal) error {
s, ok := sig.(syscall.Signal)
if !ok {
return errors.New("os: unsupported signal type")
}
// Which type of Process do we have?
if p.handle != nil {
// pidfd
return p.pidfdSendSignal(s)
} else {
// Regular PID
return p.pidSignal(s)
}
}
func (p *Process) pidSignal(s syscall.Signal) error {
if p.Pid == pidReleased {
return errProcessReleased
}
if p.Pid == pidUnset {
return errors.New("os: process not initialized")
}
p.sigMu.RLock()
defer p.sigMu.RUnlock()
switch p.pidStatus() {
case statusDone:
return ErrProcessDone
case statusReleased:
return errProcessReleased
}
return convertESRCH(syscall.Kill(p.Pid, s))
}
func convertESRCH(err error) error {
if err == syscall.ESRCH {
return ErrProcessDone
}
return err
}
func findProcess(pid int) (p *Process, err error) {
h, err := pidfdFind(pid)
if err == ErrProcessDone {
// We can't return an error here since users are not expecting
// it. Instead, return a process with a "done" state already
// and let a subsequent Signal or Wait call catch that.
return newDoneProcess(pid), nil
} else if err != nil {
// Ignore other errors from pidfdFind, as the callers
// do not expect them. Fall back to using the PID.
return newPIDProcess(pid), nil
}
// Use the handle.
return newHandleProcess(pid, h), nil
}
func (p *ProcessState) userTime() time.Duration {
return time.Duration(p.rusage.Utime.Nano()) * time.Nanosecond
}
func (p *ProcessState) systemTime() time.Duration {
return time.Duration(p.rusage.Stime.Nano()) * time.Nanosecond
}
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