@@ -12,6 +12,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// +build linux
+
 package caddycmd
 
 import (
// Copyright 2015 Matthew Holt and The Caddy Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package caddycmd

import (
	"bytes"
	"context"
	"crypto/rand"
	"encoding/json"
	"fmt"
	"io"
	"io/ioutil"
	"log"
	"net"
	"net/http"
	"os"
	"os/exec"
	"reflect"
	"runtime"
	"runtime/debug"
	"sort"
	"strings"

	"github.com/caddyserver/caddy/v2"
	"github.com/caddyserver/caddy/v2/caddyconfig"
	"github.com/caddyserver/caddy/v2/caddyconfig/caddyfile"
	"go.uber.org/zap"
)

func cmdStart(fl Flags) (int, error) {
	startCmdConfigFlag := fl.String("config")
	startCmdConfigAdapterFlag := fl.String("adapter")
	startCmdPidfileFlag := fl.String("pidfile")
	startCmdWatchFlag := fl.Bool("watch")

	// open a listener to which the child process will connect when
	// it is ready to confirm that it has successfully started
	ln, err := net.Listen("tcp", "127.0.0.1:0")
	if err != nil {
		return caddy.ExitCodeFailedStartup,
			fmt.Errorf("opening listener for success confirmation: %v", err)
	}
	defer ln.Close()

	// craft the command with a pingback address and with a
	// pipe for its stdin, so we can tell it our confirmation
	// code that we expect so that some random port scan at
	// the most unfortunate time won't fool us into thinking
	// the child succeeded (i.e. the alternative is to just
	// wait for any connection on our listener, but better to
	// ensure it's the process we're expecting - we can be
	// sure by giving it some random bytes and having it echo
	// them back to us)
	cmd := exec.Command(os.Args[0], "run", "--pingback", ln.Addr().String())
	if startCmdConfigFlag != "" {
		cmd.Args = append(cmd.Args, "--config", startCmdConfigFlag)
	}
	if startCmdConfigAdapterFlag != "" {
		cmd.Args = append(cmd.Args, "--adapter", startCmdConfigAdapterFlag)
	}
	if startCmdWatchFlag {
		cmd.Args = append(cmd.Args, "--watch")
	}
	if startCmdPidfileFlag != "" {
		cmd.Args = append(cmd.Args, "--pidfile", startCmdPidfileFlag)
	}
	stdinpipe, err := cmd.StdinPipe()
	if err != nil {
		return caddy.ExitCodeFailedStartup,
			fmt.Errorf("creating stdin pipe: %v", err)
	}
	cmd.Stdout = os.Stdout
	cmd.Stderr = os.Stderr

	// generate the random bytes we'll send to the child process
	expect := make([]byte, 32)
	_, err = rand.Read(expect)
	if err != nil {
		return caddy.ExitCodeFailedStartup, fmt.Errorf("generating random confirmation bytes: %v", err)
	}

	// begin writing the confirmation bytes to the child's
	// stdin; use a goroutine since the child hasn't been
	// started yet, and writing synchronously would result
	// in a deadlock
	go func() {
		_, _ = stdinpipe.Write(expect)
		stdinpipe.Close()
	}()

	// start the process
	err = cmd.Start()
	if err != nil {
		return caddy.ExitCodeFailedStartup, fmt.Errorf("starting caddy process: %v", err)
	}

	// there are two ways we know we're done: either
	// the process will connect to our listener, or
	// it will exit with an error
	success, exit := make(chan struct{}), make(chan error)

	// in one goroutine, we await the success of the child process
	go func() {
		for {
			conn, err := ln.Accept()
			if err != nil {
				if !strings.Contains(err.Error(), "use of closed network connection") {
					log.Println(err)
				}
				break
			}
			err = handlePingbackConn(conn, expect)
			if err == nil {
				close(success)
				break
			}
			log.Println(err)
		}
	}()

	// in another goroutine, we await the failure of the child process
	go func() {
		err := cmd.Wait() // don't send on this line! Wait blocks, but send starts before it unblocks
		exit <- err       // sending on separate line ensures select won't trigger until after Wait unblocks
	}()

	// when one of the goroutines unblocks, we're done and can exit
	select {
	case <-success:
		fmt.Printf("Successfully started Caddy (pid=%d) - Caddy is running in the background\n", cmd.Process.Pid)
	case err := <-exit:
		return caddy.ExitCodeFailedStartup,
			fmt.Errorf("caddy process exited with error: %v", err)
	}

	return caddy.ExitCodeSuccess, nil
}

func cmdRun(fl Flags) (int, error) {
	caddy.TrapSignals()

	runCmdConfigFlag := fl.String("config")
	runCmdConfigAdapterFlag := fl.String("adapter")
	runCmdResumeFlag := fl.Bool("resume")
	runCmdLoadEnvfileFlag := fl.String("envfile")
	runCmdPrintEnvFlag := fl.Bool("environ")
	runCmdWatchFlag := fl.Bool("watch")
	runCmdPidfileFlag := fl.String("pidfile")
	runCmdPingbackFlag := fl.String("pingback")

	// load all additional envs as soon as possible
	if runCmdLoadEnvfileFlag != "" {
		if err := loadEnvFromFile(runCmdLoadEnvfileFlag); err != nil {
			return caddy.ExitCodeFailedStartup,
				fmt.Errorf("loading additional environment variables: %v", err)
		}
	}

	// if we are supposed to print the environment, do that first
	if runCmdPrintEnvFlag {
		printEnvironment()
	}

	// TODO: This is TEMPORARY, until the RCs
	moveStorage()

	// load the config, depending on flags
	var config []byte
	var err error
	if runCmdResumeFlag {
		config, err = ioutil.ReadFile(caddy.ConfigAutosavePath)
		if os.IsNotExist(err) {
			// not a bad error; just can't resume if autosave file doesn't exist
			caddy.Log().Info("no autosave file exists", zap.String("autosave_file", caddy.ConfigAutosavePath))
			runCmdResumeFlag = false
		} else if err != nil {
			return caddy.ExitCodeFailedStartup, err
		} else {
			if runCmdConfigFlag == "" {
				caddy.Log().Info("resuming from last configuration",
					zap.String("autosave_file", caddy.ConfigAutosavePath))
			} else {
				// if they also specified a config file, user should be aware that we're not
				// using it (doing so could lead to data/config loss by overwriting!)
				caddy.Log().Warn("--config and --resume flags were used together; ignoring --config and resuming from last configuration",
					zap.String("autosave_file", caddy.ConfigAutosavePath))
			}
		}
	}
	// we don't use 'else' here since this value might have been changed in 'if' block; i.e. not mutually exclusive
	var configFile string
	if !runCmdResumeFlag {
		config, configFile, err = loadConfig(runCmdConfigFlag, runCmdConfigAdapterFlag)
		if err != nil {
			return caddy.ExitCodeFailedStartup, err
		}
	}

	// run the initial config
	err = caddy.Load(config, true)
	if err != nil {
		return caddy.ExitCodeFailedStartup, fmt.Errorf("loading initial config: %v", err)
	}
	caddy.Log().Info("serving initial configuration")

	// if we are to report to another process the successful start
	// of the server, do so now by echoing back contents of stdin
	if runCmdPingbackFlag != "" {
		confirmationBytes, err := ioutil.ReadAll(os.Stdin)
		if err != nil {
			return caddy.ExitCodeFailedStartup,
				fmt.Errorf("reading confirmation bytes from stdin: %v", err)
		}
		conn, err := net.Dial("tcp", runCmdPingbackFlag)
		if err != nil {
			return caddy.ExitCodeFailedStartup,
				fmt.Errorf("dialing confirmation address: %v", err)
		}
		defer conn.Close()
		_, err = conn.Write(confirmationBytes)
		if err != nil {
			return caddy.ExitCodeFailedStartup,
				fmt.Errorf("writing confirmation bytes to %s: %v", runCmdPingbackFlag, err)
		}
	}

	// if enabled, reload config file automatically on changes
	// (this better only be used in dev!)
	if runCmdWatchFlag {
		go watchConfigFile(configFile, runCmdConfigAdapterFlag)
	}

	// create pidfile
	if runCmdPidfileFlag != "" {
		err := caddy.PIDFile(runCmdPidfileFlag)
		if err != nil {
			caddy.Log().Error("unable to write PID file",
				zap.String("pidfile", runCmdPidfileFlag),
				zap.Error(err))
		}
	}

	// warn if the environment does not provide enough information about the disk
	hasXDG := os.Getenv("XDG_DATA_HOME") != "" &&
		os.Getenv("XDG_CONFIG_HOME") != "" &&
		os.Getenv("XDG_CACHE_HOME") != ""
	switch runtime.GOOS {
	case "windows":
		if os.Getenv("HOME") == "" && os.Getenv("USERPROFILE") == "" && !hasXDG {
			caddy.Log().Warn("neither HOME nor USERPROFILE environment variables are set - please fix; some assets might be stored in ./caddy")
		}
	case "plan9":
		if os.Getenv("home") == "" && !hasXDG {
			caddy.Log().Warn("$home environment variable is empty - please fix; some assets might be stored in ./caddy")
		}
	default:
		if os.Getenv("HOME") == "" && !hasXDG {
			caddy.Log().Warn("$HOME environment variable is empty - please fix; some assets might be stored in ./caddy")
		}
	}

	select {}
}

func cmdStop(fl Flags) (int, error) {
	stopCmdAddrFlag := fl.String("address")

	err := apiRequest(stopCmdAddrFlag, http.MethodPost, "/stop", nil)
	if err != nil {
		caddy.Log().Warn("failed using API to stop instance", zap.Error(err))
		return caddy.ExitCodeFailedStartup, err
	}

	return caddy.ExitCodeSuccess, nil
}

func cmdReload(fl Flags) (int, error) {
	reloadCmdConfigFlag := fl.String("config")
	reloadCmdConfigAdapterFlag := fl.String("adapter")
	reloadCmdAddrFlag := fl.String("address")

	// get the config in caddy's native format
	config, configFile, err := loadConfig(reloadCmdConfigFlag, reloadCmdConfigAdapterFlag)
	if err != nil {
		return caddy.ExitCodeFailedStartup, err
	}
	if configFile == "" {
		return caddy.ExitCodeFailedStartup, fmt.Errorf("no config file to load")
	}

	// get the address of the admin listener; use flag if specified
	adminAddr := reloadCmdAddrFlag
	if adminAddr == "" && len(config) > 0 {
		var tmpStruct struct {
			Admin caddy.AdminConfig `json:"admin"`
		}
		err = json.Unmarshal(config, &tmpStruct)
		if err != nil {
			return caddy.ExitCodeFailedStartup,
				fmt.Errorf("unmarshaling admin listener address from config: %v", err)
		}
		adminAddr = tmpStruct.Admin.Listen
	}

	err = apiRequest(adminAddr, http.MethodPost, "/load", bytes.NewReader(config))
	if err != nil {
		return caddy.ExitCodeFailedStartup, fmt.Errorf("sending configuration to instance: %v", err)
	}

	return caddy.ExitCodeSuccess, nil
}

func cmdVersion(_ Flags) (int, error) {
	goModule := caddy.GoModule()
	fmt.Print(goModule.Version)
	if goModule.Sum != "" {
		// a build with a known version will also have a checksum
		fmt.Printf(" %s", goModule.Sum)
	}
	if goModule.Replace != nil {
		fmt.Printf(" => %s", goModule.Replace.Path)
		if goModule.Replace.Version != "" {
			fmt.Printf(" %s", goModule.Replace.Version)
		}
	}
	fmt.Println()
	return caddy.ExitCodeSuccess, nil
}

func cmdBuildInfo(fl Flags) (int, error) {
	bi, ok := debug.ReadBuildInfo()
	if !ok {
		return caddy.ExitCodeFailedStartup, fmt.Errorf("no build information")
	}

	fmt.Printf("path: %s\n", bi.Path)
	fmt.Printf("main: %s %s %s\n", bi.Main.Path, bi.Main.Version, bi.Main.Sum)
	fmt.Println("dependencies:")

	for _, goMod := range bi.Deps {
		fmt.Printf("%s %s %s", goMod.Path, goMod.Version, goMod.Sum)
		if goMod.Replace != nil {
			fmt.Printf(" => %s %s %s", goMod.Replace.Path, goMod.Replace.Version, goMod.Replace.Sum)
		}
		fmt.Println()
	}
	return caddy.ExitCodeSuccess, nil
}

func cmdListModules(fl Flags) (int, error) {
	versions := fl.Bool("versions")

	bi, ok := debug.ReadBuildInfo()
	if !ok || !versions {
		// if there's no build information,
		// just print out the modules
		for _, m := range caddy.Modules() {
			fmt.Println(m)
		}
		return caddy.ExitCodeSuccess, nil
	}

	for _, modID := range caddy.Modules() {
		modInfo, err := caddy.GetModule(modID)
		if err != nil {
			// that's weird
			fmt.Println(modID)
			continue
		}

		// to get the Caddy plugin's version info, we need to know
		// the package that the Caddy module's value comes from; we
		// can use reflection but we need a non-pointer value (I'm
		// not sure why), and since New() should return a pointer
		// value, we need to dereference it first
		iface := interface{}(modInfo.New())
		if rv := reflect.ValueOf(iface); rv.Kind() == reflect.Ptr {
			iface = reflect.New(reflect.TypeOf(iface).Elem()).Elem().Interface()
		}
		modPkgPath := reflect.TypeOf(iface).PkgPath()

		// now we find the Go module that the Caddy module's package
		// belongs to; we assume the Caddy module package path will
		// be prefixed by its Go module path, and we will choose the
		// longest matching prefix in case there are nested modules
		var matched *debug.Module
		for _, dep := range bi.Deps {
			if strings.HasPrefix(modPkgPath, dep.Path) {
				if matched == nil || len(dep.Path) > len(matched.Path) {
					matched = dep
				}
			}
		}

		// if we could find no matching module, just print out
		// the module ID instead
		if matched == nil {
			fmt.Println(modID)
			continue
		}

		fmt.Printf("%s %s\n", modID, matched.Version)
	}

	return caddy.ExitCodeSuccess, nil
}

func cmdEnviron(_ Flags) (int, error) {
	printEnvironment()
	return caddy.ExitCodeSuccess, nil
}

func cmdAdaptConfig(fl Flags) (int, error) {
	adaptCmdInputFlag := fl.String("config")
	adaptCmdAdapterFlag := fl.String("adapter")
	adaptCmdPrettyFlag := fl.Bool("pretty")
	adaptCmdValidateFlag := fl.Bool("validate")

	// if no input file was specified, try a default
	// Caddyfile if the Caddyfile adapter is plugged in
	if adaptCmdInputFlag == "" && caddyconfig.GetAdapter("caddyfile") != nil {
		_, err := os.Stat("Caddyfile")
		if err == nil {
			// default Caddyfile exists
			adaptCmdInputFlag = "Caddyfile"
			caddy.Log().Info("using adjacent Caddyfile")
		} else if !os.IsNotExist(err) {
			// default Caddyfile exists, but error accessing it
			return caddy.ExitCodeFailedStartup, fmt.Errorf("accessing default Caddyfile: %v", err)
		}
	}

	if adaptCmdInputFlag == "" {
		return caddy.ExitCodeFailedStartup,
			fmt.Errorf("input file required when there is no Caddyfile in current directory (use --config flag)")
	}
	if adaptCmdAdapterFlag == "" {
		return caddy.ExitCodeFailedStartup,
			fmt.Errorf("adapter name is required (use --adapt flag or leave unspecified for default)")
	}

	cfgAdapter := caddyconfig.GetAdapter(adaptCmdAdapterFlag)
	if cfgAdapter == nil {
		return caddy.ExitCodeFailedStartup,
			fmt.Errorf("unrecognized config adapter: %s", adaptCmdAdapterFlag)
	}

	input, err := ioutil.ReadFile(adaptCmdInputFlag)
	if err != nil {
		return caddy.ExitCodeFailedStartup,
			fmt.Errorf("reading input file: %v", err)
	}

	opts := make(map[string]interface{})
	if adaptCmdPrettyFlag {
		opts["pretty"] = "true"
	}
	opts["filename"] = adaptCmdInputFlag

	adaptedConfig, warnings, err := cfgAdapter.Adapt(input, opts)
	if err != nil {
		return caddy.ExitCodeFailedStartup, err
	}

	// print warnings to stderr
	for _, warn := range warnings {
		msg := warn.Message
		if warn.Directive != "" {
			msg = fmt.Sprintf("%s: %s", warn.Directive, warn.Message)
		}
		fmt.Fprintf(os.Stderr, "[WARNING][%s] %s:%d: %s\n", adaptCmdAdapterFlag, warn.File, warn.Line, msg)
	}

	// print result to stdout
	fmt.Println(string(adaptedConfig))

	// validate output if requested
	if adaptCmdValidateFlag {
		var cfg *caddy.Config
		err = json.Unmarshal(adaptedConfig, &cfg)
		if err != nil {
			return caddy.ExitCodeFailedStartup, fmt.Errorf("decoding config: %v", err)
		}
		err = caddy.Validate(cfg)
		if err != nil {
			return caddy.ExitCodeFailedStartup, fmt.Errorf("validation: %v", err)
		}
	}

	return caddy.ExitCodeSuccess, nil
}

func cmdValidateConfig(fl Flags) (int, error) {
	validateCmdConfigFlag := fl.String("config")
	validateCmdAdapterFlag := fl.String("adapter")

	input, _, err := loadConfig(validateCmdConfigFlag, validateCmdAdapterFlag)
	if err != nil {
		return caddy.ExitCodeFailedStartup, err
	}
	input = caddy.RemoveMetaFields(input)

	var cfg *caddy.Config
	err = json.Unmarshal(input, &cfg)
	if err != nil {
		return caddy.ExitCodeFailedStartup, fmt.Errorf("decoding config: %v", err)
	}

	err = caddy.Validate(cfg)
	if err != nil {
		return caddy.ExitCodeFailedStartup, err
	}

	fmt.Println("Valid configuration")

	return caddy.ExitCodeSuccess, nil
}

func cmdFmt(fl Flags) (int, error) {
	formatCmdConfigFile := fl.Arg(0)
	if formatCmdConfigFile == "" {
		formatCmdConfigFile = "Caddyfile"
	}

	// as a special case, read from stdin if the file name is "-"
	if formatCmdConfigFile == "-" {
		input, err := ioutil.ReadAll(os.Stdin)
		if err != nil {
			return caddy.ExitCodeFailedStartup,
				fmt.Errorf("reading stdin: %v", err)
		}
		fmt.Print(string(caddyfile.Format(input)))
		return caddy.ExitCodeSuccess, nil
	}

	input, err := ioutil.ReadFile(formatCmdConfigFile)
	if err != nil {
		return caddy.ExitCodeFailedStartup,
			fmt.Errorf("reading input file: %v", err)
	}

	output := caddyfile.Format(input)

	if fl.Bool("overwrite") {
		if err := ioutil.WriteFile(formatCmdConfigFile, output, 0600); err != nil {
			return caddy.ExitCodeFailedStartup, nil
		}
	} else {
		fmt.Print(string(output))
	}

	return caddy.ExitCodeSuccess, nil
}

func cmdHelp(fl Flags) (int, error) {
	const fullDocs = `Full documentation is available at:
https://caddyserver.com/docs/command-line`

	args := fl.Args()
	if len(args) == 0 {
		s := `Caddy is an extensible server platform.

usage:
  caddy <command> [<args...>]

commands:
`
		keys := make([]string, 0, len(commands))
		for k := range commands {
			keys = append(keys, k)
		}
		sort.Strings(keys)
		for _, k := range keys {
			cmd := commands[k]
			short := strings.TrimSuffix(cmd.Short, ".")
			s += fmt.Sprintf("  %-15s %s\n", cmd.Name, short)
		}

		s += "\nUse 'caddy help <command>' for more information about a command.\n"
		s += "\n" + fullDocs + "\n"

		fmt.Print(s)

		return caddy.ExitCodeSuccess, nil
	} else if len(args) > 1 {
		return caddy.ExitCodeFailedStartup, fmt.Errorf("can only give help with one command")
	}

	subcommand, ok := commands[args[0]]
	if !ok {
		return caddy.ExitCodeFailedStartup, fmt.Errorf("unknown command: %s", args[0])
	}

	helpText := strings.TrimSpace(subcommand.Long)
	if helpText == "" {
		helpText = subcommand.Short
		if !strings.HasSuffix(helpText, ".") {
			helpText += "."
		}
	}

	result := fmt.Sprintf("%s\n\nusage:\n  caddy %s %s\n",
		helpText,
		subcommand.Name,
		strings.TrimSpace(subcommand.Usage),
	)

	if help := flagHelp(subcommand.Flags); help != "" {
		result += fmt.Sprintf("\nflags:\n%s", help)
	}

	result += "\n" + fullDocs + "\n"

	fmt.Print(result)

	return caddy.ExitCodeSuccess, nil
}

// apiRequest makes an API request to the endpoint adminAddr with the
// given HTTP method and request URI. If body is non-nil, it will be
// assumed to be Content-Type application/json.
func apiRequest(adminAddr, method, uri string, body io.Reader) error {
	// parse the admin address
	if adminAddr == "" {
		adminAddr = caddy.DefaultAdminListen
	}
	parsedAddr, err := caddy.ParseNetworkAddress(adminAddr)
	if err != nil || parsedAddr.PortRangeSize() > 1 {
		return fmt.Errorf("invalid admin address %s: %v", adminAddr, err)
	}
	origin := parsedAddr.JoinHostPort(0)
	if parsedAddr.IsUnixNetwork() {
		origin = "unixsocket" // hack so that http.NewRequest() is happy
	}

	// form the request
	req, err := http.NewRequest(method, "http://"+origin+uri, body)
	if err != nil {
		return fmt.Errorf("making request: %v", err)
	}
	if parsedAddr.IsUnixNetwork() {
		// When listening on a unix socket, the admin endpoint doesn't
		// accept any Host header because there is no host:port for
		// a unix socket's address. The server's host check is fairly
		// strict for security reasons, so we don't allow just any
		// Host header. For unix sockets, the Host header must be
		// empty. Unfortunately, Go makes it impossible to make HTTP
		// requests with an empty Host header... except with this one
		// weird trick. (Hopefully they don't fix it. It's already
		// hard enough to use HTTP over unix sockets.)
		//
		// An equivalent curl command would be something like:
		// $ curl --unix-socket caddy.sock http:/:$REQUEST_URI
		req.URL.Host = " "
		req.Host = ""
	} else {
		req.Header.Set("Origin", origin)
	}
	if body != nil {
		req.Header.Set("Content-Type", "application/json")
	}

	// make an HTTP client that dials our network type, since admin
	// endpoints aren't always TCP, which is what the default transport
	// expects; reuse is not of particular concern here
	client := http.Client{
		Transport: &http.Transport{
			DialContext: func(_ context.Context, _, _ string) (net.Conn, error) {
				return net.Dial(parsedAddr.Network, parsedAddr.JoinHostPort(0))
			},
		},
	}

	resp, err := client.Do(req)
	if err != nil {
		return fmt.Errorf("performing request: %v", err)
	}
	defer resp.Body.Close()

	// if it didn't work, let the user know
	if resp.StatusCode >= 400 {
		respBody, err := ioutil.ReadAll(io.LimitReader(resp.Body, 1024*10))
		if err != nil {
			return fmt.Errorf("HTTP %d: reading error message: %v", resp.StatusCode, err)
		}
		return fmt.Errorf("caddy responded with error: HTTP %d: %s", resp.StatusCode, respBody)
	}

	return nil
}

The build tag, i.e. `// +build linux` , means the code within this file is only readable and available when the target is Linux, which is why the build is failing for all other platform. Look at the CI results on the "Checks" tab above.