Merge pull request #64 from AkihiroSuda/lima-home

Follow-up to "Follow-up to \"Implement LIMA_HOME to override ~/.lima location\""

Author: AkihiroSuda

cmd/limactl/start.go

@@ -9,6 +9,7 @@ import (
 	"strings"
 
 	"github.com/AkihiroSuda/lima/pkg/limayaml"
+	"github.com/AkihiroSuda/lima/pkg/osutil"
 	"github.com/AkihiroSuda/lima/pkg/start"
 	"github.com/AkihiroSuda/lima/pkg/store"
 	"github.com/AkihiroSuda/lima/pkg/store/filenames"
@@ -82,11 +83,11 @@ func loadOrCreateInstance(clicontext *cli.Context) (*store.Instance, error) {
 		return nil, err
 	}
 
-	// the full path of the socket name can be at most 104 chars.
+	// the full path of the socket name must be less than UNIX_PATH_MAX chars.
 	maxSockName := filepath.Join(instDir, filenames.LongestSock)
-	if len(maxSockName) > 104 {
-		return nil, errors.Errorf("instance name %q too long: %q can be at most 104 characers, but is %d",
-			instName, maxSockName, len(maxSockName))
+	if len(maxSockName) >= osutil.UnixPathMax {
+		return nil, errors.Errorf("instance name %q too long: %q must be less than UNIX_PATH_MAX=%d characers, but is %d",
+			instName, maxSockName, osutil.UnixPathMax, len(maxSockName))
 	}
 	if _, err := os.Stat(instDir); !errors.Is(err, os.ErrNotExist) {
 		return nil, errors.Errorf("instance %q already exists (%q)", instName, instDir)

docs/internal.md

@@ -7,7 +7,7 @@ Defaults to `~/.lima`.
 Note that we intentionally avoid using `~/Library/Application Support/Lima` on macOS.
 
 We use `~/.lima` so that we can have enough space for the length of the socket path,
-which can be only 104 characters on macOS.
+which must be less than 104 characters on macOS.
 
 ### Instance directory (`${LIMA_HOME}/<INSTANCE>`)
 

pkg/osutil/osutil_linux.go

@@ -0,0 +1,4 @@
+package osutil
+
+// UnixPathMax is the value of UNIX_PATH_MAX.
+const UnixPathMax = 108

pkg/osutil/osutil_others.go

@@ -0,0 +1,6 @@
+// +build !linux
+
+package osutil
+
+// UnixPathMax is the value of UNIX_PATH_MAX.
+const UnixPathMax = 104

pkg/sshutil/sshutil.go

@@ -3,9 +3,9 @@ package sshutil
 import (
 	"os"
 	"path/filepath"
-	"runtime"
 	"strings"
 
+	"github.com/AkihiroSuda/lima/pkg/osutil"
 	"github.com/AkihiroSuda/lima/pkg/store/filenames"
 	"github.com/pkg/errors"
 	"github.com/sirupsen/logrus"
@@ -48,16 +48,8 @@ func DefaultPubKeys() []PubKey {
 
 func SSHArgs(instDir string) ([]string, error) {
 	controlSock := filepath.Join(instDir, filenames.SSHSock)
-	maxSockLen := 104
-	if runtime.GOOS == "linux" {
-		maxSockLen = 108
-	}
-	if len(controlSock) >= maxSockLen {
-		// If the instDir was under `~/Library/Application Support/Lima`,
-		// we could only have 54 chars for the user name and the inst name at maximum:
-		// len("/Users/32charsXXXXXXXXXXXXXXXXXXXXXXXXX/Library/Application Support/Lima/22charsXXXXXXXXXXXXXXX/ssh.sock") = 104
-		// So we do not use `~/Library/Application Support`.
-		return nil, errors.Errorf("socket path %q is too long: > UNIX_PATH_MAX=%d", controlSock, maxSockLen)
+	if len(controlSock) >= osutil.UnixPathMax {
+		return nil, errors.Errorf("socket path %q is too long: >= UNIX_PATH_MAX=%d", controlSock, osutil.UnixPathMax)
 	}
 	args := []string{
 		"-o", "ControlMaster=auto",

pkg/store/filenames/filenames.go

@@ -20,8 +20,8 @@ const (
 )
 
 // LongestSock is the longest socket name.
-// On macOS, the full path of the socket can be at most 104 characters.
+// On macOS, the full path of the socket (excluding the NUL terminator) must be less than 104 characters.
 // See unix(4).
 //
-// On Linux, the max length is 108.
+// On Linux, the full path must be less than 108 characters.
 const LongestSock = SerialSock