[Libguestfs] [PATCH 2/5] mltools: create a new external_command_code

[Pino Toscano]

Split most of the code from external_command to a new
external_command_code, so it is possible to get the exit code of the
process without considering it fatal.
---
 common/mltools/tools_utils.ml  | 22 ++++++++++------------
 common/mltools/tools_utils.mli |  8 ++++++++
 2 files changed, 18 insertions(+), 12 deletions(-)

diff --git a/common/mltools/tools_utils.ml b/common/mltools/tools_utils.ml
index 3b1554c5a..e6b2b5713 100644
--- a/common/mltools/tools_utils.ml
+++ b/common/mltools/tools_utils.ml
@@ -338,7 +338,13 @@ let create_standard_options argspec ?anon_fun ?(key_opts = false) ?(machine_read
   }
 
 (* Run an external command, slurp up the output as a list of lines. *)
-let external_command ?(echo_cmd = true) cmd =
+let rec external_command ?(echo_cmd = true) cmd =
+  let lines, exitcode = external_command_code ~echo_cmd cmd in
+  if exitcode <> 0 then
+    error (f_"external command ‘%s’ exited with error %d") cmd exitcode;
+  lines
+
+and external_command_code ?(echo_cmd = true) cmd =
   if echo_cmd then
     debug "%s" cmd;
   let chan = Unix.open_process_in cmd in
@@ -347,18 +353,10 @@ let external_command ?(echo_cmd = true) cmd =
    with End_of_file -> ());
   let lines = List.rev !lines in
   let stat = Unix.close_process_in chan in
-  (match stat with
-  | Unix.WEXITED 0 -> ()
-  | Unix.WEXITED i ->
-    error (f_"external command ‘%s’ exited with error %d") cmd i
-  | Unix.WSIGNALED i ->
-    error (f_"external command ‘%s’ killed by signal %d") cmd i
-  | Unix.WSTOPPED i ->
-    error (f_"external command ‘%s’ stopped by signal %d") cmd i
-  );
-  lines
+  let exitcode = do_check_exitcode cmd stat in
+  lines, exitcode
 
-let rec run_commands ?(echo_cmd = true) cmds =
+and run_commands ?(echo_cmd = true) cmds =
   let res = Array.make (List.length cmds) 0 in
   let pids =
     List.mapi (
diff --git a/common/mltools/tools_utils.mli b/common/mltools/tools_utils.mli
index ab70f583e..fb998697c 100644
--- a/common/mltools/tools_utils.mli
+++ b/common/mltools/tools_utils.mli
@@ -100,6 +100,14 @@ val create_standard_options : Getopt.speclist -> ?anon_fun:Getopt.anon_fun -> ?k
 
 val external_command : ?echo_cmd:bool -> string -> string list
 (** Run an external command, slurp up the output as a list of lines.
+    A non-zero exit code of the command is considered a fatal error.
+
+    [echo_cmd] specifies whether to output the full command on verbose
+    mode, and it's on by default. *)
+
+val external_command_code : ?echo_cmd:bool -> string -> string list * int
+(** Run an external command, slurp up the output as a list of lines,
+    and return it together with the exit code of the command.
 
     [echo_cmd] specifies whether to output the full command on verbose
     mode, and it's on by default. *)
-- 
2.20.1