Move proc locking into entrypoint

This completely cleans up all logic that used to be in crypticnet.

entrypoint/src/cmd/entrypoint/admin.go

@@ -2,7 +2,6 @@ package main
 
 import (
 	"context"
-	crypticnet "cryptic-net"
 	"cryptic-net/admin"
 	"cryptic-net/bootstrap"
 	"cryptic-net/daemon"
@@ -103,29 +102,11 @@ var subCmdAdminCreateNetwork = subCmd{
 			return fmt.Errorf("invalid hostname %q: %w", *hostName, err)
 		}
 
-		adminCreationParams := admin.CreationParams{
-			ID:     randStr(32),
-			Domain: *domain,
-		}
-
-		{
-			runtimeDirPath := envRuntimeDirPath
-
-			fmt.Fprintf(os.Stderr, "will use runtime directory %q for temporary state\n", runtimeDirPath)
-
-			if err := os.MkdirAll(runtimeDirPath, 0700); err != nil {
-				return fmt.Errorf("creating directory %q: %w", runtimeDirPath, err)
-			} else if err := crypticnet.NewProcLock(runtimeDirPath).WriteLock(); err != nil {
-				return err
-			}
-
-			defer func() {
-				fmt.Fprintf(os.Stderr, "cleaning up runtime directory %q\n", runtimeDirPath)
-				if err := os.RemoveAll(runtimeDirPath); err != nil {
-					fmt.Fprintf(os.Stderr, "error removing temporary directory %q: %v", runtimeDirPath, err)
-				}
-			}()
+		runtimeDirCleanup, err := setupAndLockRuntimeDir()
+		if err != nil {
+			return fmt.Errorf("setting up runtime directory: %w", err)
 		}
+		defer runtimeDirCleanup()
 
 		daemonConfig, err := daemon.LoadConfig(envAppDirPath, *daemonConfigPath)
 		if err != nil {
@@ -146,6 +127,11 @@ var subCmdAdminCreateNetwork = subCmd{
 			return fmt.Errorf("creating nebula cert for host: %w", err)
 		}
 
+		adminCreationParams := admin.CreationParams{
+			ID:     randStr(32),
+			Domain: *domain,
+		}
+
 		hostBootstrap := bootstrap.Bootstrap{
 			AdminCreationParams: adminCreationParams,
 			Hosts: map[string]bootstrap.Host{

entrypoint/src/cmd/entrypoint/daemon.go

@@ -10,7 +10,6 @@ import (
 	"sync"
 	"time"
 
-	crypticnet "cryptic-net"
 	"cryptic-net/bootstrap"
 	"cryptic-net/daemon"
 	"cryptic-net/garage"
@@ -236,26 +235,11 @@ var subCmdDaemon = subCmd{
 			return daemon.CopyDefaultConfig(os.Stdout, envAppDirPath)
 		}
 
-		runtimeDirPath := envRuntimeDirPath
-
-		fmt.Fprintf(os.Stderr, "will use runtime directory %q for temporary state\n", runtimeDirPath)
-
-		if err := os.MkdirAll(runtimeDirPath, 0700); err != nil {
-			return fmt.Errorf("creating directory %q: %w", runtimeDirPath, err)
-
-		} else if err := crypticnet.NewProcLock(runtimeDirPath).WriteLock(); err != nil {
-			return err
+		runtimeDirCleanup, err := setupAndLockRuntimeDir()
+		if err != nil {
+			return fmt.Errorf("setting up runtime directory: %w", err)
 		}
-
-		// do not defer the cleaning of the runtime directory until the lock has
-		// been obtained, otherwise we might delete the directory out from under
-		// the feet of an already running daemon
-		defer func() {
-			fmt.Fprintf(os.Stderr, "cleaning up runtime directory %q\n", runtimeDirPath)
-			if err := os.RemoveAll(runtimeDirPath); err != nil {
-				fmt.Fprintf(os.Stderr, "error removing temporary directory %q: %v", runtimeDirPath, err)
-			}
-		}()
+		defer runtimeDirCleanup()
 
 		var (
 			bootstrapDataDirPath = bootstrap.DataDirPath(envDataDirPath)
@@ -264,8 +248,6 @@ var subCmdDaemon = subCmd{
 			hostBootstrapPath  string
 			hostBootstrap      bootstrap.Bootstrap
 			foundHostBootstrap bool
-
-			err error
 		)
 
 		tryLoadBootstrap := func(path string) bool {

entrypoint/src/cmd/entrypoint/proc_lock.go

@@ -1,4 +1,4 @@
-package crypticnet
+package main
 
 import (
 	"errors"
@@ -12,33 +12,13 @@ import (
 
 var errDaemonNotRunning = errors.New("no cryptic-net daemon process running")
 
-// ProcLock is used to lock a process.
-type ProcLock interface {
-
-	// WriteLock creates a new lock, or errors if the lock is alread held.
-	WriteLock() error
-
-	// AssertLock returns an error if the lock already exists.
-	AssertLock() error
-}
-
-type procLock struct {
-	dir string
-}
-
-// NewProcLock returns a ProcLock which will use a file in the given directory
-// to lock the process.
-func NewProcLock(dir string) ProcLock {
-	return &procLock{dir: dir}
-}
-
-func (pl *procLock) path() string {
-	return filepath.Join(pl.dir, "lock")
+func lockFilePath() string {
+	return filepath.Join(envRuntimeDirPath, "lock")
 }
 
-func (pl *procLock) WriteLock() error {
+func writeLock() error {
 
-	lockFilePath := pl.path()
+	lockFilePath := lockFilePath()
 
 	lockFile, err := os.OpenFile(
 		lockFilePath, os.O_WRONLY|os.O_CREATE|os.O_EXCL, 0400,
@@ -63,11 +43,31 @@ func (pl *procLock) WriteLock() error {
 	return nil
 }
 
+// returns a cleanup function which will clean up the created runtime directory.
+func setupAndLockRuntimeDir() (func(), error) {
+
+	fmt.Fprintf(os.Stderr, "will use runtime directory %q for temporary state\n", envRuntimeDirPath)
+
+	if err := os.MkdirAll(envRuntimeDirPath, 0700); err != nil {
+		return nil, fmt.Errorf("creating directory %q: %w", envRuntimeDirPath, err)
+
+	} else if err := writeLock(); err != nil {
+		return nil, err
+	}
+
+	return func() {
+		fmt.Fprintf(os.Stderr, "cleaning up runtime directory %q\n", envRuntimeDirPath)
+		if err := os.RemoveAll(envRuntimeDirPath); err != nil {
+			fmt.Fprintf(os.Stderr, "error removing temporary directory %q: %v", envRuntimeDirPath, err)
+		}
+	}, nil
+}
+
 // checks that the lock file exists and that the process which created it also
 // still exists.
-func (pl *procLock) AssertLock() error {
+func assertLock() error {
 
-	lockFilePath := pl.path()
+	lockFilePath := lockFilePath()
 
 	lockFile, err := os.Open(lockFilePath)
 

entrypoint/src/cmd/entrypoint/sub_cmd.go

@@ -2,7 +2,6 @@ package main
 
 import (
 	"context"
-	crypticnet "cryptic-net"
 	"fmt"
 	"os"
 	"strings"
@@ -101,9 +100,7 @@ func (ctx subCmdCtx) doSubCmd(subCmds ...subCmd) error {
 
 	if subCmd.checkLock {
 
-		err := crypticnet.NewProcLock(envRuntimeDirPath).AssertLock()
-
-		if err != nil {
+		if err := assertLock(); err != nil {
 			return fmt.Errorf("checking lock file: %w", err)
 		}
 	}

entrypoint/src/doc.go

@@ -1,3 +0,0 @@
-// Package globals defines global constants and variables which are valid
-// across all cryptic-net processes and sub-processes.
-package crypticnet