Replaced the previous incorrect logic with an re-implementation of common.ExpandUser.

builder/oracle/oci/config.go

@@ -94,21 +94,11 @@ func NewConfig(raws ...interface{}) (*Config, error) {
 
 	var keyContent []byte
 	if c.KeyFile != "" {
-		u, err := user.Current()
+		path, err := common.ExpandUser(c.KeyFile)
 		if err != nil {
 			return nil, err
 		}
 
-		if u.HomeDir == "" {
-			return nil, fmt.Errorf("Unable to determine the home directory for the current user.")
-		}
-
-		// If c.KeyFile is not an absolute path, then it's relative so prefix it relative to the home directory
-		path := c.KeyFile
-		if !filepath.IsAbs(c.KeyFile) {
-			path = filepath.Join(u.HomeDir, c.KeyFile)
-		}
-
 		// Read API signing key
 		keyContent, err = ioutil.ReadFile(path)
 		if err != nil {

common/config.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"net/url"
 	"os"
+	"os/user"
 	"path/filepath"
 	"regexp"
 	"runtime"
@@ -206,3 +207,44 @@ func FileExistsLocally(original string) bool {
 	}
 	return true
 }
+
+func ExpandUser(path string) (string, error) {
+	var (
+		u   *user.User
+		err error
+	)
+
+	// refuse to do anything with a zero-length path
+	if len(path) == 0 {
+		return path
+	}
+
+	// If no expansion was specified, then refuse that too
+	if path[0] != "~" {
+		return path, nil
+	}
+
+	// Grab everything up to the first filepath.Separator
+	idx := strings.IndexAny(path, `/\`)
+	if idx == -1 {
+		idx = len(path)
+	}
+
+	// Now we should be able to extract the username
+	username := path[:idx]
+
+	// Check if the current user was requested
+	if username == "~" {
+		u, err = user.Current()
+	} else {
+		u, err = user.Lookup(username[1:])
+	}
+
+	// If we couldn't figure that out, then fail here
+	if err != nil {
+		return "", err
+	}
+
+	// Now we can replace the path with u.HomeDir
+	return filepath.Join(u.HomeDir, path[idx:])
+}

helper/communicator/config.go

@@ -6,10 +6,9 @@ import (
 	"io/ioutil"
 	"net"
 	"os"
-	"os/user"
-	"path/filepath"
 	"time"
 
+	"github.com/hashicorp/packer/common"
 	packerssh "github.com/hashicorp/packer/communicator/ssh"
 	"github.com/hashicorp/packer/helper/multistep"
 	helperssh "github.com/hashicorp/packer/helper/ssh"
@@ -74,19 +73,9 @@ func (c *Config) ReadSSHPrivateKeyFile() ([]byte, error) {
 	var privateKey []byte
 
 	if c.SSHPrivateKeyFile != "" {
-		u, err := user.Current()
+		keyPath, err := common.ExpandUser(c.SSHPrivateKeyFile)
 		if err != nil {
-			return []byte{}, fmt.Errorf("Error trying to determine the current user for the SSH private key: %s", err)
+			return []byte{}, fmt.Errorf("Error expanding path for SSH private key: %s", err)
-		}
-
-		if u.HomeDir == "" {
-			return []byte{}, fmt.Errorf("Error locating home directory for the SSH private key")
-		}
-
-		// If c.SSHPrivateKeyFile is not an absolute path, then it's relative and should be prefixed with u.HomeDir
-		keyPath := c.SSHPrivateKeyFile
-		if !filepath.IsAbs(c.SSHPrivateKeyFile) {
-			keyPath = filepath.Join(u.HomeDir, c.SSHPrivateKeyFile)
 		}
 
 		privateKey, err = ioutil.ReadFile(keyPath)
@@ -272,24 +261,8 @@ func (c *Config) prepareSSH(ctx *interpolate.Context) []error {
 		errs = append(errs, errors.New("An ssh_username must be specified\n  Note: some builders used to default ssh_username to \"root\"."))
 	}
 
-	// Figure out the current user's home directory
-	u, err := user.Current()
-	if err != nil {
-		errs = append(errs, fmt.Errorf("Unable to determine the current user from : %s", err))
-	} else if u.HomeDir == "" {
-		// If the home directory is empty, then set `err` so that later a failure will happen
-		err = fmt.Errorf("Unable to determine the home directory for the current user.")
-	}
-
 	if c.SSHPrivateKeyFile != "" {
-		path := c.SSHPrivateKeyFile
+		path, err := common.ExpandUser(c.SSHPrivateKeyFile)
-
-		// If c.SSHPrivateKeyFile is not an absolute path, then it's relative and should be prefixed with u.HomeDir
-		if err == nil && !filepath.IsAbs(c.SSHPrivateKeyFile) {
-			path = filepath.Join(u.HomeDir, c.SSHPrivateKeyFile)
-		}
-
-		// The `err` variable here comes from the empty home directory above
 		if err != nil {
 			errs = append(errs, fmt.Errorf(
 				"ssh_private_key_file is invalid: %s", err))
@@ -307,9 +280,7 @@ func (c *Config) prepareSSH(ctx *interpolate.Context) []error {
 			errs = append(errs, errors.New(
 				"ssh_bastion_password or ssh_bastion_private_key_file must be specified"))
 		} else if c.SSHBastionPrivateKeyFile != "" {
-			path := filepath.Join(u.HomeDir, c.SSHBastionPrivateKeyFile)
+			path, err := common.ExpandUser(c.SSHBastionPrivateKeyFile)
-
-			// The `err` variable here comes from an empty home directory
 			if err != nil {
 				errs = append(errs, fmt.Errorf(
 					"ssh_bastion_private_key_file is invalid: %s", err))

helper/communicator/step_connect_ssh.go

@@ -7,8 +7,6 @@ import (
 	"log"
 	"net"
 	"os"
-	"os/user"
-	"path/filepath"
 	"strings"
 	"time"
 
@@ -228,17 +226,12 @@ func sshBastionConfig(config *Config) (*gossh.ClientConfig, error) {
 	}
 
 	if config.SSHBastionPrivateKeyFile != "" {
-		u, err := user.Current()
+		path, err := common.ExpandUser(config.SSHBastionPrivateKeyFile)
 		if err != nil {
-			return nil, fmt.Errorf("Unable to determine the current user for the SSH bastion private key: %s", err)
+			return nil, fmt.Errorf(
+				"Error expanding path for SSH bastion private key: %s", err)
 		}
 
-		if u.HomeDir == "" {
-			return nil, fmt.Errorf("Unable to determine the current user's home directory for the SSH bastion private key.")
-		}
-
-		path := filepath.Join(u.HomeDir, config.SSHBastionPrivateKeyFile)
-
 		signer, err := helperssh.FileSigner(path)
 		if err != nil {
 			return nil, err