libguestfs/SOURCES/0068-mltools-add-run_in_guest_command-helper.patch

96 lines
3.4 KiB
Diff

From 9a8246e91ac0fa38d96691dc6025cb8b117f9cb2 Mon Sep 17 00:00:00 2001
From: Pino Toscano <ptoscano@redhat.com>
Date: Mon, 4 May 2020 15:14:46 +0200
Subject: [PATCH] mltools: add run_in_guest_command helper
Add an helper function to run a command in the guest, checking for the
host/guest compatibility. This is mostly extracted from the internal
do_run helper currently in the Customize_run module of virt-customize.
(cherry picked from commit e73eca3b73f7d0a54615c5dc55eadd09dc170035
in libguestfs-common)
---
common/mltools/tools_utils.ml | 50 ++++++++++++++++++++++++++++++++++
common/mltools/tools_utils.mli | 10 +++++++
2 files changed, 60 insertions(+)
diff --git a/common/mltools/tools_utils.ml b/common/mltools/tools_utils.ml
index 127180225..d54ec581e 100644
--- a/common/mltools/tools_utils.ml
+++ b/common/mltools/tools_utils.ml
@@ -679,3 +679,53 @@ let with_timeout op timeout ?(sleep = 2) fn =
loop ()
in
loop ()
+
+let run_in_guest_command g root ?logfile ?incompatible_fn cmd =
+ (* Is the host_cpu compatible with the guest arch? ie. Can we
+ * run commands in this guest?
+ *)
+ let guest_arch = g#inspect_get_arch root in
+ let guest_arch_compatible = guest_arch_compatible guest_arch in
+ if not guest_arch_compatible then (
+ match incompatible_fn with
+ | None -> ()
+ | Some fn -> fn ()
+ )
+ else (
+ (* Add a prologue to the scripts:
+ * - Pass environment variables through from the host.
+ * - Optionally send stdout and stderr to a log file so we capture
+ * all output in error messages.
+ * - Use setarch when running x86_64 host + i686 guest.
+ *)
+ let env_vars =
+ List.filter_map (
+ fun name ->
+ try Some (sprintf "export %s=%s" name (quote (Sys.getenv name)))
+ with Not_found -> None
+ ) [ "http_proxy"; "https_proxy"; "ftp_proxy"; "no_proxy" ] in
+ let env_vars = String.concat "\n" env_vars ^ "\n" in
+
+ let cmd =
+ match Guestfs_config.host_cpu, guest_arch with
+ | "x86_64", ("i386"|"i486"|"i586"|"i686") ->
+ sprintf "setarch i686 <<\"__EOCMD\"
+%s
+__EOCMD
+" cmd
+ | _ -> cmd in
+
+ let logfile_redirect =
+ match logfile with
+ | None -> ""
+ | Some logfile -> sprintf "exec >>%s 2>&1" (quote logfile) in
+
+ let cmd = sprintf "\
+%s
+%s
+%s
+" (logfile_redirect) env_vars cmd in
+
+ debug "running command:\n%s" cmd;
+ ignore (g#sh cmd)
+ )
diff --git a/common/mltools/tools_utils.mli b/common/mltools/tools_utils.mli
index ab70f583e..102abff4d 100644
--- a/common/mltools/tools_utils.mli
+++ b/common/mltools/tools_utils.mli
@@ -212,3 +212,13 @@ val with_timeout : string -> int -> ?sleep:int -> (unit -> 'a option) -> 'a
calls {!error} and the program exits. The error message will
contain the diagnostic string [op] to identify the operation
which timed out. *)
+
+val run_in_guest_command : Guestfs.guestfs -> string -> ?logfile:string -> ?incompatible_fn:(unit -> unit) -> string -> unit
+(** [run_in_guest_command g root ?incompatible_archs_fn cmd]
+ runs a command in the guest, which is already mounted for the
+ specified [root]. The command is run directly in case the
+ architecture of the host and the guest are compatible, optionally
+ calling [?incompatible_fn] in case they are not.
+
+ [?logfile] is an optional file in the guest to where redirect
+ stdout and stderr of the command. *)
--
2.18.4