Add HelperBinariesDir field to engine config

This field contains a list of directories which should be used to store
some helper binaries, e.g. gvproxy.

Also add a FindHelperBinary method to the config struct to get the full
path to a helper binary.

Signed-off-by: Paul Holzinger <pholzing@redhat.com>

docs/containers.conf.5.md

@@ -378,6 +378,29 @@ if you want to set environment variables for the container.
 Default method to use when logging events.
 Valid values: `file`, `journald`, and `none`.
 
+**helper_binaries_dir**=["/usr/libexec/podman", ...]
+
+A is a list of directories which are used to search for helper binaries.
+
+The default paths on Linux are:
+- `/usr/local/libexec/podman`
+- `/usr/local/lib/podman`
+- `/usr/libexec/podman`
+- `/usr/lib/podman`
+
+The default paths on macOS are:
+- `/usr/local/opt/podman/libexec`
+-	`/opt/homebrew/bin`
+-	`/opt/homebrew/opt/podman/libexec`
+- `/usr/local/bin`
+-	`/usr/local/libexec/podman`
+-	`/usr/local/lib/podman`
+-	`/usr/libexec/podman`
+-	`/usr/lib/podman`
+
+The default path on Windows is:
+- `C:\Program Files\RedHat\Podman`
+
 **hooks_dir**=["/etc/containers/oci/hooks.d", ...]
 
 Path to the OCI hooks directories for automatically executed hooks.

pkg/config/config.go

@@ -234,6 +234,10 @@ type EngineConfig struct {
 	// EventsLogger determines where events should be logged.
 	EventsLogger string `toml:"events_logger,omitempty"`
 
+	// HelperBinariesDir is a list of directories which are used to search for
+	// helper binaries.
+	HelperBinariesDir []string `toml:"helper_binaries_dir"`
+
 	// configuration files. When the same filename is present in in
 	// multiple directories, the file in the directory listed last in
 	// this slice takes precedence.
@@ -1126,3 +1130,21 @@ func (c *Config) ActiveDestination() (uri, identity string, err error) {
 	}
 	return "", "", errors.New("no service destination configured")
 }
+
+// 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) {
+	for _, path := range c.Engine.HelperBinariesDir {
+		fullpath := filepath.Join(path, name)
+		if fi, err := os.Stat(fullpath); err == nil && fi.Mode().IsRegular() {
+			return fullpath, nil
+		}
+	}
+	if searchPATH {
+		return exec.LookPath(name)
+	}
+	if len(c.Engine.HelperBinariesDir) == 0 {
+		return "", errors.Errorf("could not find %q because there are no helper binary directories configured", name)
+	}
+	return "", errors.Errorf("could not find %q in one of %v", name, c.Engine.HelperBinariesDir)
+}

pkg/config/config_darwin.go

@@ -15,3 +15,16 @@ func customConfigFile() (string, error) {
 func ifRootlessConfigPath() (string, error) {
 	return rootlessConfigPath()
 }
+
+var defaultHelperBinariesDir = []string{
+	// Homebrew install paths
+	"/usr/local/opt/podman/libexec",
+	"/opt/homebrew/bin",
+	"/opt/homebrew/opt/podman/libexec",
+	"/usr/local/bin",
+	// default paths
+	"/usr/local/libexec/podman",
+	"/usr/local/lib/podman",
+	"/usr/libexec/podman",
+	"/usr/lib/podman",
+}

pkg/config/config_linux.go

@@ -35,3 +35,10 @@ func ifRootlessConfigPath() (string, error) {
 	}
 	return "", nil
 }
+
+var defaultHelperBinariesDir = []string{
+	"/usr/local/libexec/podman",
+	"/usr/local/lib/podman",
+	"/usr/libexec/podman",
+	"/usr/lib/podman",
+}

pkg/config/config_test.go

@@ -163,6 +163,10 @@ var _ = Describe("Config", func() {
 				"TERM=xterm",
 			}
 
+			helperDirs := []string{
+				"/somepath",
+			}
+
 			// Then
 			gomega.Expect(err).To(gomega.BeNil())
 			gomega.Expect(defaultConfig.Engine.CgroupManager).To(gomega.Equal("systemd"))
@@ -172,6 +176,7 @@ var _ = Describe("Config", func() {
 			gomega.Expect(defaultConfig.Engine.NumLocks).To(gomega.BeEquivalentTo(2048))
 			gomega.Expect(defaultConfig.Engine.OCIRuntimes).To(gomega.Equal(OCIRuntimeMap))
 			gomega.Expect(defaultConfig.Containers.HTTPProxy).To(gomega.Equal(false))
+			gomega.Expect(defaultConfig.Engine.HelperBinariesDir).To(gomega.Equal(helperDirs))
 		})
 
 		It("test GetDefaultEnvEx", func() {

pkg/config/config_windows.go

@@ -13,3 +13,7 @@ func customConfigFile() (string, error) {
 func ifRootlessConfigPath() (string, error) {
 	return os.Getenv("APPDATA") + "\\containers\\containers.conf", nil
 }
+
+var defaultHelperBinariesDir = []string{
+	"C:\\Program Files\\RedHat\\Podman",
+}

pkg/config/containers.conf

@@ -341,6 +341,15 @@ default_sysctls = [
 #
 #events_logger = "journald"
 
+# A is a list of directories which are used to search for helper binaries.
+#
+#helper_binaries_dir = [
+#  "/usr/local/libexec/podman",
+#  "/usr/local/lib/podman",
+#  "/usr/libexec/podman",
+#  "/usr/lib/podman",
+#]
+
 # Path to OCI hooks directories for automatically executed hooks.
 #
 #hooks_dir = [

pkg/config/default.go

@@ -247,6 +247,7 @@ func defaultConfigFromMemory() (*EngineConfig, error) {
 	c.StaticDir = filepath.Join(storeOpts.GraphRoot, "libpod")
 	c.VolumePath = filepath.Join(storeOpts.GraphRoot, "volumes")
 
+	c.HelperBinariesDir = defaultHelperBinariesDir
 	c.HooksDir = DefaultHooksDirs
 	c.ImageDefaultTransport = _defaultTransport
 	c.StateType = BoltDBStateStore

pkg/config/testdata/containers_default.conf

@@ -164,6 +164,13 @@ no_pivot_root = false
 # namespace is set, all containers and pods are visible.
 #namespace = ""
 
+# A is a list of directories which are used to search for helper binaries.
+#
+helper_binaries_dir = [
+ "/somepath",
+]
+
+
 # Path to OCI hooks directories for automatically executed hooks.
 hooks_dir = [
 ]