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-rw-r--r--libpod/oci_conmon_exec_linux.go48
-rw-r--r--libpod/util.go17
2 files changed, 49 insertions, 16 deletions
diff --git a/libpod/oci_conmon_exec_linux.go b/libpod/oci_conmon_exec_linux.go
index dc5dd03df..faf86ea5b 100644
--- a/libpod/oci_conmon_exec_linux.go
+++ b/libpod/oci_conmon_exec_linux.go
@@ -126,20 +126,25 @@ func (r *ConmonOCIRuntime) ExecContainerHTTP(ctr *Container, sessionID string, o
}()
attachChan := make(chan error)
+ conmonPipeDataChan := make(chan conmonPipeData)
go func() {
// attachToExec is responsible for closing pipes
- attachChan <- attachExecHTTP(ctr, sessionID, req, w, streams, pipes, detachKeys, options.Terminal, cancel, hijackDone, holdConnOpen)
+ attachChan <- attachExecHTTP(ctr, sessionID, req, w, streams, pipes, detachKeys, options.Terminal, cancel, hijackDone, holdConnOpen, execCmd, conmonPipeDataChan, ociLog)
close(attachChan)
}()
- // Wait for conmon to succeed, when return.
- if err := execCmd.Wait(); err != nil {
- return -1, nil, errors.Wrapf(err, "cannot run conmon")
- }
+ // NOTE: the channel is needed to communicate conmon's data. In case
+ // of an error, the error will be written on the hijacked http
+ // connection such that remote clients will receive the error.
+ pipeData := <-conmonPipeDataChan
- pid, err := readConmonPipeData(pipes.syncPipe, ociLog)
+ return pipeData.pid, attachChan, pipeData.err
+}
- return pid, attachChan, err
+// conmonPipeData contains the data when reading from conmon's pipe.
+type conmonPipeData struct {
+ pid int
+ err error
}
// ExecContainerDetached executes a command in a running container, but does
@@ -488,9 +493,16 @@ func (r *ConmonOCIRuntime) startExec(c *Container, sessionID string, options *Ex
}
// Attach to a container over HTTP
-func attachExecHTTP(c *Container, sessionID string, r *http.Request, w http.ResponseWriter, streams *HTTPAttachStreams, pipes *execPipes, detachKeys []byte, isTerminal bool, cancel <-chan bool, hijackDone chan<- bool, holdConnOpen <-chan bool) (deferredErr error) {
+func attachExecHTTP(c *Container, sessionID string, r *http.Request, w http.ResponseWriter, streams *HTTPAttachStreams, pipes *execPipes, detachKeys []byte, isTerminal bool, cancel <-chan bool, hijackDone chan<- bool, holdConnOpen <-chan bool, execCmd *exec.Cmd, conmonPipeDataChan chan<- conmonPipeData, ociLog string) (deferredErr error) {
+ // NOTE: As you may notice, the attach code is quite complex.
+ // Many things happen concurrently and yet are interdependent.
+ // If you ever change this function, make sure to write to the
+ // conmonPipeDataChan in case of an error.
+
if pipes == nil || pipes.startPipe == nil || pipes.attachPipe == nil {
- return errors.Wrapf(define.ErrInvalidArg, "must provide a start and attach pipe to finish an exec attach")
+ err := errors.Wrapf(define.ErrInvalidArg, "must provide a start and attach pipe to finish an exec attach")
+ conmonPipeDataChan <- conmonPipeData{-1, err}
+ return err
}
defer func() {
@@ -509,17 +521,20 @@ func attachExecHTTP(c *Container, sessionID string, r *http.Request, w http.Resp
// set up the socket path, such that it is the correct length and location for exec
sockPath, err := c.execAttachSocketPath(sessionID)
if err != nil {
+ conmonPipeDataChan <- conmonPipeData{-1, err}
return err
}
// 2: read from attachFd that the parent process has set up the console socket
if _, err := readConmonPipeData(pipes.attachPipe, ""); err != nil {
+ conmonPipeDataChan <- conmonPipeData{-1, err}
return err
}
// 2: then attach
conn, err := openUnixSocket(sockPath)
if err != nil {
+ conmonPipeDataChan <- conmonPipeData{-1, err}
return errors.Wrapf(err, "failed to connect to container's attach socket: %v", sockPath)
}
defer func() {
@@ -540,11 +555,13 @@ func attachExecHTTP(c *Container, sessionID string, r *http.Request, w http.Resp
// Perform hijack
hijacker, ok := w.(http.Hijacker)
if !ok {
+ conmonPipeDataChan <- conmonPipeData{-1, err}
return errors.Errorf("unable to hijack connection")
}
httpCon, httpBuf, err := hijacker.Hijack()
if err != nil {
+ conmonPipeDataChan <- conmonPipeData{-1, err}
return errors.Wrapf(err, "error hijacking connection")
}
@@ -555,10 +572,23 @@ func attachExecHTTP(c *Container, sessionID string, r *http.Request, w http.Resp
// Force a flush after the header is written.
if err := httpBuf.Flush(); err != nil {
+ conmonPipeDataChan <- conmonPipeData{-1, err}
return errors.Wrapf(err, "error flushing HTTP hijack header")
}
go func() {
+ // Wait for conmon to succeed, when return.
+ if err := execCmd.Wait(); err != nil {
+ conmonPipeDataChan <- conmonPipeData{-1, err}
+ } else {
+ pid, err := readConmonPipeData(pipes.syncPipe, ociLog)
+ if err != nil {
+ hijackWriteError(err, c.ID(), isTerminal, httpBuf)
+ conmonPipeDataChan <- conmonPipeData{pid, err}
+ } else {
+ conmonPipeDataChan <- conmonPipeData{pid, err}
+ }
+ }
// We need to hold the connection open until the complete exec
// function has finished. This channel will be closed in a defer
// in that function, so we can wait for it here.
diff --git a/libpod/util.go b/libpod/util.go
index bf9bf2542..391208fb9 100644
--- a/libpod/util.go
+++ b/libpod/util.go
@@ -235,20 +235,16 @@ func checkDependencyContainer(depCtr, ctr *Container) error {
return nil
}
-// hijackWriteErrorAndClose writes an error to a hijacked HTTP session and
-// closes it. Intended to HTTPAttach function.
-// If error is nil, it will not be written; we'll only close the connection.
-func hijackWriteErrorAndClose(toWrite error, cid string, terminal bool, httpCon io.Closer, httpBuf *bufio.ReadWriter) {
+// hijackWriteError writes an error to a hijacked HTTP session.
+func hijackWriteError(toWrite error, cid string, terminal bool, httpBuf *bufio.ReadWriter) {
if toWrite != nil {
- errString := []byte(fmt.Sprintf("%v\n", toWrite))
+ errString := []byte(fmt.Sprintf("Error: %v\n", toWrite))
if !terminal {
// We need a header.
header := makeHTTPAttachHeader(2, uint32(len(errString)))
if _, err := httpBuf.Write(header); err != nil {
logrus.Errorf("Error writing header for container %s attach connection error: %v", cid, err)
}
- // TODO: May want to return immediately here to avoid
- // writing garbage to the socket?
}
if _, err := httpBuf.Write(errString); err != nil {
logrus.Errorf("Error writing error to container %s HTTP attach connection: %v", cid, err)
@@ -257,6 +253,13 @@ func hijackWriteErrorAndClose(toWrite error, cid string, terminal bool, httpCon
logrus.Errorf("Error flushing HTTP buffer for container %s HTTP attach connection: %v", cid, err)
}
}
+}
+
+// hijackWriteErrorAndClose writes an error to a hijacked HTTP session and
+// closes it. Intended to HTTPAttach function.
+// If error is nil, it will not be written; we'll only close the connection.
+func hijackWriteErrorAndClose(toWrite error, cid string, terminal bool, httpCon io.Closer, httpBuf *bufio.ReadWriter) {
+ hijackWriteError(toWrite, cid, terminal, httpBuf)
if err := httpCon.Close(); err != nil {
logrus.Errorf("Error closing container %s HTTP attach connection: %v", cid, err)