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util/iocommand: timeout kill on close + other hardening

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This commit is contained in:
Christian Schwarz 2018-11-06 23:37:25 +01:00
parent 1aae7b222f
commit 7a75a4d384
1 changed files with 19 additions and 6 deletions
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25
util/iocommand.go
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@ -4,15 +4,18 @@ import (
"bytes"
"context"
"fmt"
"github.com/zrepl/zrepl/util/envconst"
"io"
"os"
"os/exec"
"syscall"
"time"
)
// An IOCommand exposes a forked process's std(in|out|err) through the io.ReadWriteCloser interface.
type IOCommand struct {
Cmd *exec.Cmd
kill context.CancelFunc
Stdin io.WriteCloser
Stdout io.ReadCloser
StderrBuf *bytes.Buffer
@ -52,6 +55,7 @@ func NewIOCommand(ctx context.Context, command string, args []string, stderrBufS
c = &IOCommand{}
ctx, c.kill = context.WithCancel(ctx)
c.Cmd = exec.CommandContext(ctx, command, args...)
if c.Stdout, err = c.Cmd.StdoutPipe(); err != nil {
@ -81,14 +85,24 @@ func (c *IOCommand) Start() (err error) {
func (c *IOCommand) Read(buf []byte) (n int, err error) {
n, err = c.Stdout.Read(buf)
if err == io.EOF {
if waitErr := c.doWait(); waitErr != nil {
if waitErr := c.doWait(context.Background()); waitErr != nil {
err = waitErr
}
}
return
}
func (c *IOCommand) doWait() (err error) {
func (c *IOCommand) doWait(ctx context.Context) (err error) {
go func() {
dl, ok := ctx.Deadline()
if !ok {
return
}
time.Sleep(dl.Sub(time.Now()))
c.kill()
c.Stdout.Close()
c.Stdin.Close()
}()
waitErr := c.Cmd.Wait()
var wasUs bool = false
var waitStatus syscall.WaitStatus
@ -133,10 +147,9 @@ func (c *IOCommand) Close() (err error) {
if c.Cmd.ProcessState == nil {
// racy...
err = syscall.Kill(c.Cmd.Process.Pid, syscall.SIGTERM)
if err != nil {
return
}
return c.doWait()
ctx, cancel := context.WithTimeout(context.Background(), envconst.Duration("IOCOMMAND_TIMEOUT", 10*time.Second))
defer cancel()
return c.doWait(ctx)
} else {
return c.ExitResult.Error
}