[Libguestfs] [PATCH] mllib: check for executable existance in run_command (RHBZ#1362357)

run_command uses Unix.create_process which forks a child process, and executes execve: the latter fails when the executable does not exist, triggering the exit which, in older OCaml versions [1], also runs the at_exit handlers. Since there is not much that can be done to avoid this on the OCaml side, to keep run_command working also in older OCaml version then manually search for the existance of the given executable, exiting with code 127 (as a shell does) in this case. [1] http://caml.inria.fr/mantis/view.php?id=7209 --- mllib/common_utils.ml | 32 ++++++++++++++++++++------------ 1 file changed, 20 insertions(+), 12 deletions(-) diff --git a/mllib/common_utils.ml b/mllib/common_utils.ml index 14f4935..fdca713 100644 --- a/mllib/common_utils.ml +++ b/mllib/common_utils.ml @@ -677,18 +677,26 @@ let external_command ?(echo_cmd = true) cmd = let run_command ?(echo_cmd = true) args = if echo_cmd then debug "%s" (stringify_args args); - let pid = - Unix.create_process (List.hd args) (Array.of_list args) Unix.stdin - Unix.stdout Unix.stderr in - let _, stat = Unix.waitpid [] pid in - match stat with - | Unix.WEXITED i -> i - | Unix.WSIGNALED i -> - error (f_"external command '%s' killed by signal %d") - (stringify_args args) i - | Unix.WSTOPPED i -> - error (f_"external command '%s' stopped by signal %d") - (stringify_args args) i + let app = List.hd args in + try + let app = + if Filename.is_relative app then which app + else (Unix.access app [Unix.X_OK]; app) in + let pid = + Unix.create_process app (Array.of_list args) Unix.stdin + Unix.stdout Unix.stderr in + let _, stat = Unix.waitpid [] pid in + match stat with + | Unix.WEXITED i -> i + | Unix.WSIGNALED i -> + error (f_"external command '%s' killed by signal %d") + (stringify_args args) i + | Unix.WSTOPPED i -> + error (f_"external command '%s' stopped by signal %d") + (stringify_args args) i + with + | Executable_not_found tool -> 127 + | Unix.Unix_error (errcode, _, _) when errcode = Unix.ENOENT -> 127 let shell_command ?(echo_cmd = true) cmd = if echo_cmd then -- 2.7.4