rootless: support a custom arg to the new process

let the process running as euid != 0 pass down an argument to the
process running in the user namespace.  This will be useful for
commands like rm -a that needs to join different namespaces, so that
we can re-exec separately for each of them.

Signed-off-by: Giuseppe Scrivano <gscrivan@redhat.com>

1 files changed, 27 insertions, 6 deletions

diff --git a/pkg/rootless/rootless_unsupported.go b/pkg/rootless/rootless_unsupported.go
index 1823c023e..54e70961b 100644
--- a/pkg/rootless/rootless_unsupported.go
+++ b/pkg/rootless/rootless_unsupported.go
@@ -11,10 +11,18 @@ func IsRootless() bool {
 	return false
 }
 
+// BecomeRootInUserNS re-exec podman in a new userNS.  It returns whether podman was re-executed
+// into a new user namespace and the return code from the re-executed podman process.
+// If podman was re-executed the caller needs to propagate the error code returned by the child
+// process.  It is a convenience function for BecomeRootInUserNSWithOpts with a default configuration.
+func BecomeRootInUserNS() (bool, int, error) {
+	return false, -1, errors.New("this function is not supported on this os")
+}
+
 // BecomeRootInUserNS is a stub function that always returns false and an
 // error on unsupported OS's
-func BecomeRootInUserNS() (bool, int, error) {
-	return false, -1, errors.New("this function is not supported on this os1")
+func BecomeRootInUserNSWithOpts(opts *Opts) (bool, int, error) {
+	return false, -1, errors.New("this function is not supported on this os")
 }
 
 // GetRootlessUID returns the UID of the user in the parent userNS
@@ -34,18 +42,31 @@ func SkipStorageSetup() bool {
 // JoinNS re-exec podman in a new userNS and join the user namespace of the specified
 // PID.
 func JoinNS(pid uint) (bool, int, error) {
-	return false, -1, errors.New("this function is not supported on this os2")
+	return false, -1, errors.New("this function is not supported on this os")
 }
 
 // JoinNSPath re-exec podman in a new userNS and join the owner user namespace of the
 // specified path.
 func JoinNSPath(path string) (bool, int, error) {
-	return false, -1, errors.New("this function is not supported on this os3")
+	return false, -1, errors.New("this function is not supported on this os")
+}
+
+// JoinDirectUserAndMountNSWithOpts re-exec podman in a new userNS and join the user and
+// mount namespace of the specified PID without looking up its parent.  Useful to join
+// directly the conmon process.
+func JoinDirectUserAndMountNSWithOpts(pid uint, opts *Opts) (bool, int, error) {
+	return false, -1, errors.New("this function is not supported on this os")
 }
 
 // JoinDirectUserAndMountNS re-exec podman in a new userNS and join the user and mount
 // namespace of the specified PID without looking up its parent.  Useful to join directly
-// the conmon process.
+// the conmon process.  It is a convenience function for JoinDirectUserAndMountNSWithOpts
+// with a default configuration.
 func JoinDirectUserAndMountNS(pid uint) (bool, int, error) {
-	return false, -1, errors.New("this function is not supported on this os4")
+	return false, -1, errors.New("this function is not supported on this os")
+}
+
+// Argument returns the argument that was set for the rootless session.
+func Argument() string {
+	return ""
 }