unschroot: enable opening /dev/stdout

When stdout is an (unnamed) pipe, it usually has permission 0o644. Since
we change uids, /dev/stdout cannot be opened unless we chmod it first.
This causes some packages such as supervisor to fail to build.

1 files changed, 4 insertions, 0 deletions

diff --git a/examples/unschroot.py b/examples/unschroot.py
index b9d4923..47d2a3c 100755
--- a/examples/unschroot.py
+++ b/examples/unschroot.py
@@ -23,6 +23,7 @@ import pwd
 import shutil
 import signal
 import socket
+import stat
 import sys
 import tempfile
 import typing
@@ -210,6 +211,9 @@ def do_run_session(args: argparse.Namespace) -> None:
     pidfd: int
     if pid == 0:
         mainsock.close()
+        for fd in (1, 2):
+            if stat.S_ISFIFO(os.fstat(fd).st_mode):
+                os.fchmod(fd, 0o666)
         os.chdir(session.path)
         ns = (
             linuxnamespaces.CloneFlags.NEWUSER