Add basic C bindings to start and stop Syncthing and invoke its CLI

c-bindings/c_bindings.c

@@ -0,0 +1,11 @@
+#include "c_bindings.h"
+
+libst_logging_callback_function_t libst_logging_callback_function = NULL;
+
+void libst_invoke_logging_callback(int log_level, const char *message, size_t message_size)
+{
+	if (!libst_logging_callback_function) {
+		return;
+	}
+	libst_logging_callback_function(log_level, message, message_size);
+}

c-bindings/c_bindings.go

@@ -0,0 +1,241 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"unsafe"
+	"path/filepath"
+	_ "net/http/pprof" // Need to import this to support STPROFILER.
+
+	"github.com/syncthing/syncthing/lib/build"
+	"github.com/syncthing/syncthing/lib/config"
+	"github.com/syncthing/syncthing/lib/events"
+	"github.com/syncthing/syncthing/lib/logger"
+	"github.com/syncthing/syncthing/lib/locations"
+	"github.com/syncthing/syncthing/lib/protocol"
+	"github.com/syncthing/syncthing/lib/svcutil"
+	"github.com/syncthing/syncthing/lib/syncthing"
+	"github.com/syncthing/syncthing/cmd/syncthing/cli"
+	"github.com/syncthing/syncthing/cmd/syncthing"
+	"github.com/thejerf/suture/v4"
+)
+
+// include header for required C helper functions (so the following comment is NO comment)
+
+// #include "c_bindings.h"
+import "C"
+
+var theApp *syncthing.App
+var myID protocol.DeviceID
+var cliArgs []string
+
+const (
+	tlsDefaultCommonName = "syncthing"
+)
+
+//export libst_own_device_id
+func libst_own_device_id() string {
+	return myID.String()
+}
+
+//export libst_init_logging
+func libst_init_logging() {
+	l.AddHandler(logger.LevelVerbose, func(level logger.LogLevel, msg string) {
+		runes := []byte(msg)
+		length := len(runes)
+		if length <= 0 {
+			return
+		}
+		C.libst_invoke_logging_callback(C.int(level), (*C.char)(unsafe.Pointer(&runes[0])), C.size_t(len(runes)))
+	})
+}
+
+//export libst_clear_cli_args
+func libst_clear_cli_args(command string) {
+	if command == "cli" {
+		cliArgs = []string{}
+	} else {
+		cliArgs = []string{command}
+	}
+}
+
+//export libst_append_cli_arg
+func libst_append_cli_arg(arg string) {
+	cliArgs = append(cliArgs, arg)
+}
+
+//export libst_run_cli
+func libst_run_cli() int {
+	if err := cli.RunWithArgs(cliArgs); err != nil {
+		fmt.Println(err)
+		return 1
+	}
+	return 0
+}
+
+//export libst_run_main
+func libst_run_main() int {
+	if err := syncthing_main.RunWithArgs(cliArgs); err != nil {
+		fmt.Println(err)
+		return 1
+	}
+	return 0
+}
+
+//export libst_run_syncthing
+func libst_run_syncthing(configDir string, dataDir string, guiAddress string, guiApiKey string, verbose bool, allowNewerConfig bool, noDefaultConfig bool, skipPortProbing bool, ensureConfigDirExists bool, ensureDataDirExists bool) int {
+	// return if already running (for simplicity we only allow one Syncthing instance at at time for now)
+	if theApp != nil {
+		return 0
+	}
+
+	// set specified GUI address and API key
+	if guiAddress != "" {
+		os.Setenv("STGUIADDRESS", guiAddress)
+	}
+	if guiApiKey != "" {
+		os.Setenv("STGUIAPIKEY", guiApiKey)
+	}
+
+	// set specified config dir
+	if configDir != "" {
+		if !filepath.IsAbs(configDir) {
+			var err error
+			configDir, err = filepath.Abs(configDir)
+			if err != nil {
+				l.Warnln("Failed to make config path absolute:", err)
+				return 3
+			}
+		}
+		if err := locations.SetBaseDir(locations.ConfigBaseDir, configDir); err != nil {
+			l.Warnln(err)
+			return 3
+		}
+	}
+
+	// set specified database dir
+	if dataDir != "" {
+		if !filepath.IsAbs(dataDir) {
+			var err error
+			dataDir, err = filepath.Abs(dataDir)
+			if err != nil {
+				l.Warnln("Failed to make database path absolute:", err)
+				return 3
+			}
+		}
+		if err := locations.SetBaseDir(locations.DataBaseDir, dataDir); err != nil {
+			l.Warnln(err)
+			return 3
+		}
+	}
+
+	// ensure that the config directory exists
+	if ensureConfigDirExists {
+		if err := syncthing.EnsureDir(locations.GetBaseDir(locations.ConfigBaseDir), 0700); err != nil {
+			l.Warnln("Failed to create config directory:", err)
+			return 4
+		}
+	}
+
+	// ensure that the database directory exists
+	if dataDir != "" && ensureDataDirExists {
+		if err := syncthing.EnsureDir(locations.GetBaseDir(locations.DataBaseDir), 0700); err != nil {
+			l.Warnln("Failed to create database directory:", err)
+			return 4
+		}
+	}
+
+	// ensure that we have a certificate and key
+	cert, certErr := syncthing.LoadOrGenerateCertificate(
+		locations.Get(locations.CertFile),
+		locations.Get(locations.KeyFile),
+	)
+	if certErr != nil {
+		l.Warnln("Failed to load/generate certificate:", certErr)
+		return 1
+	}
+
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	// earlyService is a supervisor that runs the services needed for or
+	// before app startup; the event logger, and the config service.
+	spec := svcutil.SpecWithDebugLogger(l)
+	earlyService := suture.New("early", spec)
+	earlyService.ServeBackground(ctx)
+
+	evLogger := events.NewLogger()
+	earlyService.Add(evLogger)
+
+	// load config
+	configLocation := locations.Get(locations.ConfigFile)
+	l.Infoln("Loading config from:", configLocation)
+	cfgWrapper, cfgErr := syncthing.LoadConfigAtStartup(configLocation, cert, evLogger, allowNewerConfig, noDefaultConfig, skipPortProbing)
+	if cfgErr != nil {
+		l.Warnln("Failed to initialize config:", cfgErr)
+		return 2
+	}
+	if cfgService, ok := cfgWrapper.(suture.Service); ok {
+		earlyService.Add(cfgService)
+	}
+
+	// open database
+	dbFile := locations.Get(locations.Database)
+	l.Infoln("Opening database from:", dbFile)
+	ldb, dbErr := syncthing.OpenDBBackend(dbFile, config.TuningAuto)
+	if dbErr != nil {
+		l.Warnln("Error opening database:", dbErr)
+		return 4
+	}
+
+	appOpts := syncthing.Options{
+		ProfilerAddr: os.Getenv("STPROFILER"),
+		NoUpgrade: true,
+		Verbose: verbose,
+	}
+	var err error
+	theApp, err = syncthing.New(cfgWrapper, ldb, evLogger, cert, appOpts)
+	if err != nil {
+		l.Warnln("Failed to start Syncthing:", err)
+		return svcutil.ExitError.AsInt()
+	}
+
+	// start Syncthing and block until it has finished
+	returnCode := 0
+	if err := theApp.Start(); err != nil {
+		returnCode = svcutil.ExitError.AsInt()
+	}
+	returnCode = theApp.Wait().AsInt();
+	theApp = nil
+	return returnCode
+}
+
+//export libst_stop_syncthing
+func libst_stop_syncthing() int {
+	if theApp != nil {
+		return int(theApp.Stop(svcutil.ExitSuccess))
+	} else {
+		return 0;
+	}
+}
+
+//export libst_reset_database
+func libst_reset_database() {
+	os.RemoveAll(locations.Get(locations.Database))
+}
+
+//export libst_syncthing_version
+func libst_syncthing_version() *C.char {
+	return C.CString(build.Version)
+}
+
+//export libst_long_syncthing_version
+func libst_long_syncthing_version() *C.char {
+	return C.CString(build.LongVersion)
+}
+
+func main() {
+    // prevent "runtime.main_main·f: function main is undeclared in the main package"
+}
+

c-bindings/c_bindings.h

@@ -0,0 +1,11 @@
+#ifndef LIBSYNCTHING_INTERNAL_H
+#define LIBSYNCTHING_INTERNAL_H
+
+#include <stddef.h>
+
+// allow registration of callback function
+typedef void (*libst_logging_callback_function_t) (int logLevel, const char *msg, size_t msgSize);
+extern libst_logging_callback_function_t libst_logging_callback_function;
+extern void libst_invoke_logging_callback(int log_level, const char *message, size_t message_size);
+
+#endif // LIBSYNCTHING_INTERNAL_H

c-bindings/debug.go

@@ -0,0 +1,15 @@
+// Copyright (C) 2014 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at https://mozilla.org/MPL/2.0/.
+
+package main
+
+import (
+	"github.com/syncthing/syncthing/lib/logger"
+)
+
+var (
+	l = logger.DefaultLogger.NewFacility("main", "Main package")
+)

cmd/syncthing/blockprof.go

@@ -4,7 +4,7 @@
 // License, v. 2.0. If a copy of the MPL was not distributed with this file,
 // You can obtain one at https://mozilla.org/MPL/2.0/.
 
-package main
+package syncthing_main
 
 import (
 	"fmt"

cmd/syncthing/cli/main.go

@@ -7,12 +7,10 @@
 package cli
 
 import (
-	"bufio"
 	"fmt"
-	"os"
 
 	"github.com/alecthomas/kong"
-	"github.com/flynn-archive/go-shlex"
+	"github.com/willabides/kongplete"
 
 	"github.com/syncthing/syncthing/cmd/syncthing/cmdutil"
 	"github.com/syncthing/syncthing/lib/config"
@@ -59,37 +57,22 @@ func (cli CLI) AfterApply(kongCtx *kong.Context) error {
 
 type stdinCommand struct{}
 
-func (*stdinCommand) Run() error {
-	// Drop the `-` not to recurse into self.
-	args := make([]string, len(os.Args)-1)
-	copy(args, os.Args)
-
-	fmt.Println("Reading commands from stdin...", args)
-	scanner := bufio.NewScanner(os.Stdin)
-	for scanner.Scan() {
-		input, err := shlex.Split(scanner.Text())
-		if err != nil {
-			return fmt.Errorf("parsing input: %w", err)
-		}
-		if len(input) == 0 {
-			continue
-		}
-
-		var cli CLI
-		p, err := kong.New(&cli)
-		if err != nil {
-			// can't happen, really
-			return fmt.Errorf("creating parser: %w", err)
-		}
-		ctx, err := p.Parse(input)
-		if err != nil {
-			fmt.Println("Error:", err)
-			continue
-		}
-		if err := ctx.Run(); err != nil {
-			fmt.Println("Error:", err)
-			continue
-		}
+func RunWithArgs(args []string) error {
+	var cli CLI
+	p, err := kong.New(&cli)
+	if err != nil {
+		// can't happen, really
+		return fmt.Errorf("creating parser: %w", err)
 	}
-	return scanner.Err()
+	kongplete.Complete(p)
+	ctx, err := p.Parse(args)
+	if err != nil {
+		fmt.Println("Error:", err)
+		return err
+	}
+	if err := ctx.Run(); err != nil {
+		fmt.Println("Error:", err)
+		return err
+	}
+	return nil
 }

cmd/syncthing/crash_reporting.go

@@ -4,7 +4,7 @@
 // License, v. 2.0. If a copy of the MPL was not distributed with this file,
 // You can obtain one at https://mozilla.org/MPL/2.0/.
 
-package main
+package syncthing_main
 
 import (
 	"bytes"

cmd/syncthing/crash_reporting_test.go

@@ -4,7 +4,7 @@
 // License, v. 2.0. If a copy of the MPL was not distributed with this file,
 // You can obtain one at https://mozilla.org/MPL/2.0/.
 
-package main
+package syncthing_main
 
 import (
 	"bytes"

cmd/syncthing/debug.go

@@ -4,12 +4,12 @@
 // License, v. 2.0. If a copy of the MPL was not distributed with this file,
 // You can obtain one at https://mozilla.org/MPL/2.0/.
 
-package main
+package syncthing_main
 
 import (
 	"github.com/syncthing/syncthing/lib/logger"
 )
 
 var (
-	l = logger.DefaultLogger.NewFacility("main", "Main package")
+	l = logger.DefaultLogger.NewFacility("syncthing_main", "Syncthing package")
 )

cmd/syncthing/heapprof.go

@@ -4,7 +4,7 @@
 // License, v. 2.0. If a copy of the MPL was not distributed with this file,
 // You can obtain one at https://mozilla.org/MPL/2.0/.
 
-package main
+package syncthing_main
 
 import (
 	"fmt"

cmd/syncthing/main.go

@@ -4,7 +4,7 @@
 // License, v. 2.0. If a copy of the MPL was not distributed with this file,
 // You can obtain one at https://mozilla.org/MPL/2.0/.
 
-package main
+package syncthing_main
 
 import (
 	"bytes"
@@ -34,7 +34,6 @@ import (
 	"github.com/thejerf/suture/v4"
 	"github.com/willabides/kongplete"
 
-	"github.com/syncthing/syncthing/cmd/syncthing/cli"
 	"github.com/syncthing/syncthing/cmd/syncthing/cmdutil"
 	"github.com/syncthing/syncthing/cmd/syncthing/decrypt"
 	"github.com/syncthing/syncthing/cmd/syncthing/generate"
@@ -137,8 +136,6 @@ var entrypoint struct {
 	Serve              serveOptions                 `cmd:"" help:"Run Syncthing"`
 	Generate           generate.CLI                 `cmd:"" help:"Generate key and config, then exit"`
 	Decrypt            decrypt.CLI                  `cmd:"" help:"Decrypt or verify an encrypted folder"`
-	Cli                cli.CLI                      `cmd:"" help:"Command line interface for Syncthing"`
-	InstallCompletions kongplete.InstallCompletions `cmd:"" help:"Print commands to install shell completions"`
 }
 
 // serveOptions are the options for the `syncthing serve` command.
@@ -210,12 +207,10 @@ func defaultVars() kong.Vars {
 	return vars
 }
 
-func main() {
+func RunWithArgs(args []string) error {
 	// First some massaging of the raw command line to fit the new model.
 	// Basically this means adding the default command at the front, and
 	// converting -options to --options.
-
-	args := os.Args[1:]
 	switch {
 	case len(args) == 0:
 		// Empty command line is equivalent to just calling serve
@@ -255,6 +250,7 @@ func main() {
 	ctx.BindTo(l, (*logger.Logger)(nil)) // main logger available to subcommands
 	err = ctx.Run()
 	parser.FatalIfErrorf(err)
+	return err
 }
 
 func helpHandler(options kong.HelpOptions, ctx *kong.Context) error {

cmd/syncthing/monitor.go

@@ -4,7 +4,7 @@
 // License, v. 2.0. If a copy of the MPL was not distributed with this file,
 // You can obtain one at https://mozilla.org/MPL/2.0/.
 
-package main
+package syncthing_main
 
 import (
 	"bufio"

cmd/syncthing/monitor_test.go

@@ -4,7 +4,7 @@
 // License, v. 2.0. If a copy of the MPL was not distributed with this file,
 // You can obtain one at https://mozilla.org/MPL/2.0/.
 
-package main
+package syncthing_main
 
 import (
 	"io"

cmd/syncthing/openurl_unix.go

@@ -7,7 +7,7 @@
 //go:build !windows
 // +build !windows
 
-package main
+package syncthing_main
 
 import (
 	"os/exec"

cmd/syncthing/openurl_windows.go

@@ -7,7 +7,7 @@
 //go:build windows
 // +build windows
 
-package main
+package syncthing_main
 
 import "os/exec"
 

cmd/syncthing/perfstats_unix.go

@@ -7,7 +7,7 @@
 //go:build !solaris && !windows
 // +build !solaris,!windows
 
-package main
+package syncthing_main
 
 import (
 	"fmt"

cmd/syncthing/perfstats_unsupported.go

@@ -7,7 +7,7 @@
 //go:build solaris || windows
 // +build solaris windows
 
-package main
+package syncthing_main
 
 func startPerfStats() {
 }

cmd/syncthing/traceback.go

@@ -7,7 +7,7 @@
 //go:build go1.7
 // +build go1.7
 
-package main
+package syncthing_main
 
 import "runtime/debug"