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Merge pull request #3153 from thepwagner/issue-3118

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runtime/v1/linux/proc/io: io race
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Michael Crosby 2019-04-01 16:36:49 -04:00 committed by GitHub
commit 341b99d6e2
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GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 27 additions and 4 deletions
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31
runtime/v1/linux/proc/io.go
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@ -27,8 +27,10 @@ import (
"os/exec"
"path/filepath"
"sync"
"sync/atomic"
"syscall"
"github.com/containerd/containerd/log"
"github.com/containerd/containerd/namespaces"
"github.com/containerd/containerd/runtime/proc"
"github.com/containerd/fifo"
@ -122,7 +124,7 @@ func createIO(ctx context.Context, id string, ioUID, ioGID int, stdio proc.Stdio
}
func copyPipes(ctx context.Context, rio runc.IO, stdin, stdout, stderr string, wg, cwg *sync.WaitGroup) error {
var sameFile io.WriteCloser
var sameFile *countingWriteCloser
for _, i := range []struct {
name string
dest func(wc io.WriteCloser, rc io.Closer)
@ -136,7 +138,9 @@ func copyPipes(ctx context.Context, rio runc.IO, stdin, stdout, stderr string, w
cwg.Done()
p := bufPool.Get().(*[]byte)
defer bufPool.Put(p)
io.CopyBuffer(wc, rio.Stdout(), *p)
if _, err := io.CopyBuffer(wc, rio.Stdout(), *p); err != nil {
log.G(ctx).Warn("error copying stdout")
}
wg.Done()
wc.Close()
if rc != nil {
@ -153,7 +157,9 @@ func copyPipes(ctx context.Context, rio runc.IO, stdin, stdout, stderr string, w
cwg.Done()
p := bufPool.Get().(*[]byte)
defer bufPool.Put(p)
io.CopyBuffer(wc, rio.Stderr(), *p)
if _, err := io.CopyBuffer(wc, rio.Stderr(), *p); err != nil {
log.G(ctx).Warn("error copying stderr")
}
wg.Done()
wc.Close()
if rc != nil {
@ -180,6 +186,7 @@ func copyPipes(ctx context.Context, rio runc.IO, stdin, stdout, stderr string, w
}
} else {
if sameFile != nil {
sameFile.count++
i.dest(sameFile, nil)
continue
}
@ -187,7 +194,10 @@ func copyPipes(ctx context.Context, rio runc.IO, stdin, stdout, stderr string, w
return fmt.Errorf("containerd-shim: opening %s failed: %s", i.name, err)
}
if stdout == stderr {
sameFile = fw
sameFile = &countingWriteCloser{
WriteCloser: fw,
count: 1,
}
}
}
i.dest(fw, fr)
@ -212,6 +222,19 @@ func copyPipes(ctx context.Context, rio runc.IO, stdin, stdout, stderr string, w
return nil
}
// countingWriteCloser masks io.Closer() until close has been invoked a certain number of times.
type countingWriteCloser struct {
io.WriteCloser
count int64
}
func (c *countingWriteCloser) Close() error {
if atomic.AddInt64(&c.count, -1) > 0 {
return nil
}
return c.WriteCloser.Close()
}
// isFifo checks if a file is a fifo
// if the file does not exist then it returns false
func isFifo(path string) (bool, error) {