Merge pull request containers#1127 from filbranden/bindir1

config: Allow specifying helper dirs with $BINDIR as base directory

pkg/config/config.go

@@ -27,6 +27,8 @@ const (
 	_configPath = "containers/containers.conf"
 	// UserOverrideContainersConfig holds the containers config path overridden by the rootless user
 	UserOverrideContainersConfig = ".config/" + _configPath
+	// Token prefix for looking for helper binary under $BINDIR
+	bindirPrefix = "$BINDIR"
 )
 
 // RuntimeStateStore is a constant indicating which state store implementation
@@ -1248,17 +1250,62 @@ func (c *Config) ActiveDestination() (uri, identity string, err error) {
 	return "", "", errors.New("no service destination configured")
 }
 
+var (
+	bindirFailed = false
+	bindirCached = ""
+)
+
+func findBindir() string {
+	if bindirCached != "" || bindirFailed {
+		return bindirCached
+	}
+	execPath, err := os.Executable()
+	if err == nil {
+		// Resolve symbolic links to find the actual binary file path.
+		execPath, err = filepath.EvalSymlinks(execPath)
+	}
+	if err != nil {
+		// If failed to find executable (unlikely to happen), warn about it.
+		// The bindirFailed flag will track this, so we only warn once.
+		logrus.Warnf("Failed to find $BINDIR: %v", err)
+		bindirFailed = true
+		return ""
+	}
+	bindirCached = filepath.Dir(execPath)
+	return bindirCached
+}
+
 // FindHelperBinary will search the given binary name in the configured directories.
 // If searchPATH is set to true it will also search in $PATH.
 func (c *Config) FindHelperBinary(name string, searchPATH bool) (string, error) {
 	dirList := c.Engine.HelperBinariesDir
+	bindirPath := ""
+	bindirSearched := false
 
 	// If set, search this directory first. This is used in testing.
 	if dir, found := os.LookupEnv("CONTAINERS_HELPER_BINARY_DIR"); found {
 		dirList = append([]string{dir}, dirList...)
 	}
 
 	for _, path := range dirList {
+		if path == bindirPrefix || strings.HasPrefix(path, bindirPrefix+string(filepath.Separator)) {
+			// Calculate the path to the executable first time we encounter a $BINDIR prefix.
+			if !bindirSearched {
+				bindirSearched = true
+				bindirPath = findBindir()
+			}
+			// If there's an error, don't stop the search for the helper binary.
+			// findBindir() will have warned once during the first failure.
+			if bindirPath == "" {
+				continue
+			}
+			// Replace the $BINDIR prefix with the path to the directory of the current binary.
+			if path == bindirPrefix {
+				path = bindirPath
+			} else {
+				path = filepath.Join(bindirPath, strings.TrimPrefix(path, bindirPrefix+string(filepath.Separator)))
+			}
+		}
 		fullpath := filepath.Join(path, name)
 		if fi, err := os.Stat(fullpath); err == nil && fi.Mode().IsRegular() {
 			return fullpath, nil

pkg/config/config_darwin.go

@@ -35,4 +35,6 @@ var defaultHelperBinariesDir = []string{
 	"/usr/local/lib/podman",
 	"/usr/libexec/podman",
 	"/usr/lib/podman",
+	// Relative to the binary directory
+	"$BINDIR/../libexec/podman",
 }