contrib: add recvtty proof-of-concept
This is a proof-of-concept for the --console-socket API. It just acts as a dumb input-output copy process (nowhere near as good as the internal runC one since it doesn't handle console resizes or signals). It also provides a test-friendly mode that will be used in the bats integration tests. This patch is part of the console rewrite patchset. Signed-off-by: Aleksa Sarai <asarai@suse.de>
This commit is contained in:
Aleksa Sarai
parent
7df64f8886
commit
1543444ada
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@ -1,5 +1,6 @@
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vendor/pkg
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/runc
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contrib/cmd/recvtty/recvtty
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Godeps/_workspace/src/github.com/opencontainers/runc
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man/man8
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release
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24
Makefile
24
Makefile
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@ -1,7 +1,8 @@
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.PHONY: dbuild man \
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.PHONY: all dbuild man \
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localtest localunittest localintegration \
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test unittest integration
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SOURCES := $(shell find . 2>&1 | grep -E '.*\.(c|h|go)$$')
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PREFIX := $(DESTDIR)/usr/local
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BINDIR := $(PREFIX)/sbin
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GIT_BRANCH := $(shell git rev-parse --abbrev-ref HEAD 2>/dev/null)
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@ -26,13 +27,23 @@ VERSION := ${shell cat ./VERSION}
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SHELL := $(shell command -v bash 2>/dev/null)
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all: $(RUNC_LINK)
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.DEFAULT: runc
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runc: $(SOURCES) | $(RUNC_LINK)
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go build -i -ldflags "-X main.gitCommit=${COMMIT} -X main.version=${VERSION}" -tags "$(BUILDTAGS)" -o runc .
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static: $(RUNC_LINK)
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CGO_ENABLED=1 go build -i -tags "$(BUILDTAGS) cgo static_build" -ldflags "-w -extldflags -static -X main.gitCommit=${COMMIT} -X main.version=${VERSION}" -o runc .
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all: runc recvtty
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release: $(RUNC_LINK)
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recvtty: contrib/cmd/recvtty/recvtty
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contrib/cmd/recvtty/recvtty: $(SOURCES) | $(RUNC_LINK)
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go build -i -ldflags "-X main.gitCommit=${COMMIT} -X main.version=${VERSION}" -tags "$(BUILDTAGS)" -o contrib/cmd/recvtty/recvtty ./contrib/cmd/recvtty
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static: $(SOURCES) | $(RUNC_LINK)
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CGO_ENABLED=1 go build -i -tags "$(BUILDTAGS) cgo static_build" -ldflags "-w -extldflags -static -X main.gitCommit=${COMMIT} -X main.version=${VERSION}" -o runc .
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CGO_ENABLED=1 go build -i -tags "$(BUILDTAGS) cgo static_build" -ldflags "-w -extldflags -static -X main.gitCommit=${COMMIT} -X main.version=${VERSION}" -o contrib/cmd/recvtty/recvtty ./contrib/cmd/recvtty
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release: $(RUNC_LINK) | $(RUNC_LINK)
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@flag_list=(seccomp selinux apparmor static ambient); \
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unset expression; \
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for flag in "$${flag_list[@]}"; do \
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@ -62,7 +73,7 @@ $(RUNC_LINK):
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ln -sfn $(CURDIR) $(RUNC_LINK)
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dbuild: runcimage
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docker run --rm -v $(CURDIR):/go/src/$(PROJECT) --privileged $(RUNC_IMAGE) make
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docker run --rm -v $(CURDIR):/go/src/$(PROJECT) --privileged $(RUNC_IMAGE) make clean all
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lint:
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go vet ./...
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@ -113,6 +124,7 @@ uninstall-man:
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clean:
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rm -f runc
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rm -f contrib/cmd/recvtty/recvtty
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rm -f $(RUNC_LINK)
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rm -rf $(GOPATH)/pkg
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rm -rf $(RELEASE_DIR)
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@ -0,0 +1,247 @@
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/*
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* Copyright 2016 SUSE LLC
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package main
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import (
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"fmt"
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"io"
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"io/ioutil"
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"net"
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"os"
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"strings"
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"github.com/opencontainers/runc/libcontainer"
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"github.com/opencontainers/runc/libcontainer/utils"
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"github.com/urfave/cli"
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)
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// version will be populated by the Makefile, read from
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// VERSION file of the source code.
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var version = ""
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// gitCommit will be the hash that the binary was built from
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// and will be populated by the Makefile
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var gitCommit = ""
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const (
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usage = `Open Container Initiative contrib/cmd/recvtty
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recvtty is a reference implementation of a consumer of runC's --console-socket
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API. It has two main modes of operation:
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* single: Only permit one terminal to be sent to the socket, which is
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then hooked up to the stdio of the recvtty process. This is useful
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for rudimentary shell management of a container.
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* null: Permit as many terminals to be sent to the socket, but they
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are read to /dev/null. This is used for testing, and imitates the
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old runC API's --console=/dev/pts/ptmx hack which would allow for a
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similar trick. This is probably not what you want to use, unless
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you're doing something like our bats integration tests.
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To use recvtty, just specify a socket path at which you want to receive
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terminals:
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$ recvtty [--mode <single|null>] socket.sock
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`
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)
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func bail(err error) {
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fmt.Fprintf(os.Stderr, "[recvtty] fatal error: %v\n", err)
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os.Exit(1)
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}
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func handleSingle(path string) error {
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// Open a socket.
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ln, err := net.Listen("unix", path)
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if err != nil {
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return err
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}
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defer ln.Close()
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// We only accept a single connection, since we can only really have
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// one reader for os.Stdin. Plus this is all a PoC.
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conn, err := ln.Accept()
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if err != nil {
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return err
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}
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defer conn.Close()
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// Close ln, to allow for other instances to take over.
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ln.Close()
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// Get the fd of the connection.
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unixconn, ok := conn.(*net.UnixConn)
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if !ok {
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return fmt.Errorf("failed to cast to unixconn")
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}
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socket, err := unixconn.File()
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if err != nil {
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return err
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}
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defer socket.Close()
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// Get the master file descriptor from runC.
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master, err := utils.RecvFd(socket)
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if err != nil {
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return err
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}
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// Print the file descriptor tag.
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ti, err := libcontainer.GetTerminalInfo(master.Name())
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if err != nil {
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return err
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}
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fmt.Printf("[recvtty] received masterfd: container '%s'\n", ti.ContainerID)
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// Copy from our stdio to the master fd.
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quitChan := make(chan struct{})
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go func() {
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io.Copy(os.Stdout, master)
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quitChan <- struct{}{}
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}()
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go func() {
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io.Copy(master, os.Stdin)
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quitChan <- struct{}{}
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}()
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// Only close the master fd once we've stopped copying.
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<-quitChan
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master.Close()
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return nil
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}
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func handleNull(path string) error {
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// Open a socket.
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ln, err := net.Listen("unix", path)
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if err != nil {
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return err
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}
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defer ln.Close()
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// As opposed to handleSingle we accept as many connections as we get, but
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// we don't interact with Stdin at all (and we copy stdout to /dev/null).
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for {
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conn, err := ln.Accept()
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if err != nil {
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return err
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}
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go func(conn net.Conn) {
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// Don't leave references lying around.
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defer conn.Close()
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// Get the fd of the connection.
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unixconn, ok := conn.(*net.UnixConn)
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if !ok {
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return
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}
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socket, err := unixconn.File()
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if err != nil {
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return
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}
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defer socket.Close()
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// Get the master file descriptor from runC.
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master, err := utils.RecvFd(socket)
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if err != nil {
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return
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}
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// Print the file descriptor tag.
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ti, err := libcontainer.GetTerminalInfo(master.Name())
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if err != nil {
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bail(err)
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}
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fmt.Printf("[recvtty] received masterfd: container '%s'\n", ti.ContainerID)
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// Just do a dumb copy to /dev/null.
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devnull, err := os.OpenFile("/dev/null", os.O_RDWR, 0)
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if err != nil {
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// TODO: Handle this nicely.
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return
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}
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io.Copy(devnull, master)
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devnull.Close()
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}(conn)
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}
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}
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func main() {
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app := cli.NewApp()
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app.Name = "recvtty"
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app.Usage = usage
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// Set version to be the same as runC.
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var v []string
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if version != "" {
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v = append(v, version)
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}
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if gitCommit != "" {
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v = append(v, fmt.Sprintf("commit: %s", gitCommit))
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}
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app.Version = strings.Join(v, "\n")
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// Set the flags.
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app.Flags = []cli.Flag{
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cli.StringFlag{
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Name: "mode, m",
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Value: "single",
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Usage: "Mode of operation (single or null)",
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},
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cli.StringFlag{
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Name: "pid-file",
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Value: "",
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Usage: "Path to write daemon process ID to",
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},
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}
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app.Action = func(ctx *cli.Context) error {
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args := ctx.Args()
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if len(args) != 1 {
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return fmt.Errorf("need to specify a single socket path")
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}
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path := ctx.Args()[0]
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pidPath := ctx.String("pid-file")
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if pidPath != "" {
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pid := fmt.Sprintf("%d\n", os.Getpid())
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if err := ioutil.WriteFile(pidPath, []byte(pid), 0644); err != nil {
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return err
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}
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}
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switch ctx.String("mode") {
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case "single":
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if err := handleSingle(path); err != nil {
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return err
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}
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case "null":
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if err := handleNull(path); err != nil {
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return err
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}
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default:
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return fmt.Errorf("need to select a valid mode: %s", ctx.String("mode"))
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}
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return nil
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}
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if err := app.Run(os.Args); err != nil {
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bail(err)
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}
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}
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