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cio.copyIO: fix pipes potentially not being closed (Windows)

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The defer functions were checking the local variable, and would therefore
not be executed, as the function returned if an error occurred.

Perhaps best illustrated when renaming the local variables;

    if fifos.Stdin != "" {
        l, err1 := winio.ListenPipe(fifos.Stdin, nil)
        if err1 != nil {
            return nil, errors.Wrapf(err1, "failed to create stdin pipe %s", fifos.Stdin)
        }
        defer func(l net.Listener) {
            if err1 != nil {
                l.Close()
            }
        }(l)
        // ...
    }

    if fifos.Stdout != "" {
        l, err2 := winio.ListenPipe(fifos.Stdout, nil)
        if err2 != nil {
            return nil, errors.Wrapf(err2, "failed to create stdout pipe %s", fifos.Stdout)
        }
        defer func(l net.Listener) {
            if err2 != nil {
                l.Close()
            }
        }(l)
        // ....
    }

This patch changes the function to use a named return variable, and to use
a single `defer()` that closes all pipes.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
This commit is contained in:
Sebastiaan van Stijn 2021-01-29 12:31:46 +01:00
parent baf6c1d5e2
commit 219fa3d0a5
No known key found for this signature in database
GPG Key ID: 76698F39D527CE8C
1 changed files with 13 additions and 17 deletions
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30
cio/io_windows.go
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@ -20,7 +20,6 @@ import (
"context"
"fmt"
"io"
"net"
winio "github.com/Microsoft/go-winio"
"github.com/containerd/containerd/log"
@ -43,21 +42,28 @@ func NewFIFOSetInDir(_, id string, terminal bool) (*FIFOSet, error) {
}, nil), nil
}
func copyIO(fifos *FIFOSet, ioset *Streams) (*cio, error) {
func copyIO(fifos *FIFOSet, ioset *Streams) (_ *cio, retErr error) {
var (
set []io.Closer
)
defer func() {
if retErr == nil {
return
}
for _, closer := range set {
if closer == nil {
continue
}
_ = closer.Close()
}
}()
if fifos.Stdin != "" {
l, err := winio.ListenPipe(fifos.Stdin, nil)
if err != nil {
return nil, errors.Wrapf(err, "failed to create stdin pipe %s", fifos.Stdin)
}
defer func(l net.Listener) {
if err != nil {
l.Close()
}
}(l)
set = append(set, l)
go func() {
@ -81,11 +87,6 @@ func copyIO(fifos *FIFOSet, ioset *Streams) (*cio, error) {
if err != nil {
return nil, errors.Wrapf(err, "failed to create stdout pipe %s", fifos.Stdout)
}
defer func(l net.Listener) {
if err != nil {
l.Close()
}
}(l)
set = append(set, l)
go func() {
@ -109,11 +110,6 @@ func copyIO(fifos *FIFOSet, ioset *Streams) (*cio, error) {
if err != nil {
return nil, errors.Wrapf(err, "failed to create stderr pipe %s", fifos.Stderr)
}
defer func(l net.Listener) {
if err != nil {
l.Close()
}
}(l)
set = append(set, l)
go func() {