WIP: clone shim

tools/clone/clone_shim.c

@@ -0,0 +1,2 @@
+#include <linux/sched.h>
+#include <caml/mlvalues.h>

tools/clone/clone_shim.ml

@@ -0,0 +1,82 @@
+let usage_msg = "clone [options] [program [arguments]]"
+
+let ipc = ref false
+let mount = ref false
+let network = ref false
+let pid = ref false
+let uts = ref false
+let user = ref false
+let cgroup = ref false
+let time = ref false
+
+let verbose = ref false
+
+let program_args = ref []
+let anon_fun arg =
+  program_args := arg::!program_args
+
+let speclist = [
+  ("-i", Arg.Set ipc,     "Clone into a new IPC namespace");
+  ("-m", Arg.Set mount,   "Clone into a new mount namespace");
+  ("-n", Arg.Set network, "Clone into a new network namespace");
+  ("-p", Arg.Set pid,     "Clone into a new PID namespace");
+  ("-u", Arg.Set uts,     "Clone into a new UTS (Unix Time Sharing) namespace");
+  ("-U", Arg.Set user,    "Clone into a new user namespace");
+  ("-C", Arg.Set cgroup,  "Clone into a new IPC namespace");
+  ("-T", Arg.Set time,    "Clone into a new time namespace");
+
+  ("-v", Arg.Set verbose, "Verbose logging")
+]
+
+let veprintf = if !verbose then Printf.eprintf else Printf.eprintf
+
+type pid_t = int
+
+type clone_args = {
+  (** Flags for the clone call *)
+  flags: int;
+
+  (** Pointer to where to store the pidfd *)
+  pidfd: pid_t ref option;
+
+  (** Where to place the child thread ID in the child's memory *)
+  child_tid: pid_t ref option;
+
+  (** Where to place the child thread ID in the parent's memory *)
+  parent_tid: pid_t ref option;
+
+  (** Signal to deliver to parent on child's termination *)
+  exit_signal: int;
+
+  (** Stack for the child if the parent and child share memory *)
+  stack: bytes ref;
+
+  (* stack_size: included in stack *)
+
+  (** Location of new thread local storage *)
+  tls: int ref;
+
+  (** Optional list of specific pids for one or more of the namespaces *)
+  set_tid: pid_t list option;
+
+  (* set_tid_size: included in set_tid *)
+}
+
+external clone3: unit -> unit = "test"
+
+let () =
+  Arg.parse speclist anon_fun usage_msg;
+
+  if !ipc then begin
+    veprintf "cloning into a new IPC namespace\n";
+  end;
+
+  if !mount then veprintf "cloning into a new mount namespace\n";
+  if !network then veprintf "cloning into a new network namespace\n";
+  if !pid then veprintf "cloning into a new PID namespace\n";
+  if !uts then veprintf "cloning into a new UTS namespace\n";
+  if !user then veprintf "cloning into a new user namespace\n";
+  if !cgroup then veprintf "cloning into a new cgroup namespace\n";
+  if !time then veprintf "cloning into a new time namespace\n";
+
+  clone3 ();