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https://github.com/libguestfs/libguestfs.git
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3435938f43
The child (chrooted) process wrote its answer on the pipe and then
exited. Meanwhile the parent waiting for the child to exit before
reading from the pipe. Thus if the output was larger than a Linux
pipebuffer then the whole thing would deadlock.
(cherry picked from commit 94e64b28be)
86 lines
2.1 KiB
OCaml
86 lines
2.1 KiB
OCaml
(* guestfs-inspection
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* Copyright (C) 2009-2020 Red Hat Inc.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*)
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open Printf
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open Unix
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open Std_utils
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open Unix_utils
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type t = {
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name : string;
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chroot : string;
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}
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let create ?(name = "<unnamed>") ?(chroot = Sysroot.sysroot ()) () =
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{ name = name; chroot = chroot }
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let f t func arg =
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if verbose () then
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eprintf "chroot: %s: running '%s'\n%!" t.chroot t.name;
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let rfd, wfd = pipe () in
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let pid = fork () in
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if pid = 0 then (
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(* Child. *)
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close rfd;
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chdir t.chroot;
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chroot t.chroot;
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let ret =
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try Either (func arg)
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with exn -> Or exn in
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try
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let chan = out_channel_of_descr wfd in
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output_value chan ret;
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Pervasives.flush chan;
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Exit._exit 0
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with
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exn ->
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prerr_endline (Printexc.to_string exn);
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Exit._exit 1
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);
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(* Parent. *)
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close wfd;
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let chan = in_channel_of_descr rfd in
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let ret = input_value chan in
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close_in chan;
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let _, status = waitpid [] pid in
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(match status with
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| WEXITED 0 -> ()
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| WEXITED i ->
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close rfd;
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failwithf "chroot ‘%s’ exited with non-zero error %d" t.name i
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| WSIGNALED i ->
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close rfd;
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failwithf "chroot ‘%s’ killed by signal %d" t.name i
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| WSTOPPED i ->
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close rfd;
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failwithf "chroot ‘%s’ stopped by signal %d" t.name i
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);
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match ret with
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| Either ret -> ret
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| Or exn -> raise exn
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