[buildd-tools-devel] Bug#584831: schroot: please add an option to avoid fork()

[Timo Lindfors]

Source: schroot
Version: 1.4.2-1
Severity: wishlist

Some background info: I was trying to help a friend get his new laptop
work with debian lenny:

When I tried to trick gdm into running Xorg from an unstable chroot I
noticed X would just die with "Caught signal terminated" right after
startup. However, the following wrapper worked:

#include <unistd.h>
int main(int argc, char **argv) {
   chroot("/versions/sid");	
   chdir("/versions/sid");
   execlp ("/usr/bin/X", "/usr/bin/X", ":0", "-audit", "0","-auth", "/var/lib/gdm/:0.Xauth", "-nolisten", "tcp", "vt7", NULL);
   return 0;
}

It seems that gdm does not tolerate it if the "command=" in gdm.conf
forks. By avoiding fork with

diff --git a/sbuild/sbuild-session.cc b/sbuild/sbuild-session.cc
index 220a4fa..ec9f863 100644
--- a/sbuild/sbuild-session.cc
+++ b/sbuild/sbuild-session.cc
@@ -1292,6 +1292,9 @@ session::run_chroot (sbuild::chroot::ptr& session_chroot)
   assert(!session_chroot->get_name().empty());

   pid_t pid;
+
+  run_child(session_chroot);
+
   if ((pid = fork()) == -1)
     {
       throw error(CHILD_FORK, strerror(errno));


I was able to make gdm happy. Could you please consider adding this
behind some --no-fork option? I would imaging that it is not very
uncommon to need to run a newer X server and one of the easiest ways
to do that is to run it from an unstable chroot. (Backports don't even
have a bug tracking system but insist on a mailing list last time I
checked).


-- System Information:
Debian Release: squeeze/sid
  APT prefers unstable
  APT policy: (500, 'unstable')
Architecture: amd64 (x86_64)

Kernel: Linux 2.6.32-3-amd64 (SMP w/2 CPU cores)
Locale: LANG=C, LC_CTYPE=fi_FI (charmap=ISO-8859-1)
Shell: /bin/sh linked to /bin/bash

Versions of packages schroot depends on:
ii  libboost-filesystem1.42.0     1.42.0-3   filesystem operations (portable pa
ii  libboost-program-options1.42. 1.42.0-3   program options library for C++
ii  libboost-regex1.42.0          1.42.0-3   regular expression library for C++
ii  libboost-system1.42.0         1.42.0-3   Operating system (e.g. diagnostics
ii  libc6                         2.11.1-2   Embedded GNU C Library: Shared lib
ii  libgcc1                       1:4.4.4-4  GCC support library
ii  liblockdev1                   1.0.3-1.4  Run-time shared library for lockin
ii  libpam0g                      1.1.1-3    Pluggable Authentication Modules l
ii  libstdc++6                    4.4.4-4    The GNU Standard C++ Library v3
ii  libuuid1                      2.17.2-2   Universally Unique ID library
ii  schroot-common                1.4.2-1    common files for schroot

schroot recommends no packages.

Versions of packages schroot suggests:
pn  aufs-modules | unionfs-module <none>     (no description available)
ii  debootstrap                   1.0.23     Bootstrap a basic Debian system
pn  lvm2                          <none>     (no description available)
ii  unzip                         6.0-4      De-archiver for .zip files

-- no debconf information