Prevents removal of `podman.sock` file using `podman system reset` command

The `podman system reset` removes the `RunDirectory` directory as part of the machine reset, where `podman.sock` is usually stored.

Fixes: https://issues.redhat.com/browse/RHEL-71320

Signed-off-by: Jan Rodák <hony.com@seznam.cz>

cmd/podman/system/reset.go

@@ -20,6 +20,7 @@ var (
 	systemResetDescription = `Reset podman storage back to default state
 
   All containers will be stopped and removed, and all images, volumes, networks and container content will be removed.
+  This command does not restart podman.service and podman.socket systemd units. You may need to manually restart it after running this command.
 `
 	systemResetCommand = &cobra.Command{
 		Annotations:       map[string]string{registry.EngineMode: registry.ABIMode},

cmd/podman/system/reset_machine.go

@@ -67,7 +67,7 @@ func resetMachine() error {
 		logrus.Errorf("unable to remove machine data dir %q: %q", dirs.DataDir.GetPath(), err)
 	}
 
-	if err := utils.GuardedRemoveAll(dirs.RuntimeDir.GetPath()); err != nil {
+	if err := utils.RemoveFilesExcept(dirs.RuntimeDir.GetPath(), "podman.sock"); err != nil {
 		logrus.Errorf("unable to remove machine runtime dir %q: %q", dirs.RuntimeDir.GetPath(), err)
 	}
 

docs/source/markdown/podman-system-reset.1.md

@@ -19,6 +19,8 @@ or `volume_path`.
 of the relevant configurations. If the administrator modified the configuration files first,
 `podman system reset` might not be able to clean up the previous storage.
 
+`podman system reset` does not restart podman.service and podman.socket systemd units. You may need to manually restart it after running this command.
+
 ## OPTIONS
 #### **--force**, **-f**
 

utils/utils.go

@@ -6,6 +6,7 @@ import (
 	"io"
 	"os"
 	"os/exec"
+	"path/filepath"
 	"strings"
 	"time"
 
@@ -119,6 +120,27 @@ func GuardedRemoveAll(path string) error {
 	return os.RemoveAll(path)
 }
 
+// RemoveFilesExcept removes all files in a directory except for the one specified
+// by excludeFile and will not delete certain catastrophic paths.
+func RemoveFilesExcept(path string, excludeFile string) error {
+	if path == "" || path == "/" {
+		return fmt.Errorf("refusing to recursively delete `%s`", path)
+	}
+
+	files, err := os.ReadDir(path)
+	if err != nil {
+		return err
+	}
+	for _, file := range files {
+		if file.Name() != excludeFile {
+			if err := os.RemoveAll(filepath.Join(path, file.Name())); err != nil {
+				return err
+			}
+		}
+	}
+	return nil
+}
+
 func ProgressBar(prefix string, size int64, onComplete string) (*mpb.Progress, *mpb.Bar) {
 	p := mpb.New(
 		mpb.WithWidth(80), // Do not go below 80, see bug #17718