Bug#667001: autopkgtest: adt-virt-schroot chokes on empty root-users/root-groups or non-existent names

[Colin Watson]

Package: autopkgtest
Version: 2.0.1
Severity: normal
Tags: patch

The (largely automatically-generated) configuration for the schroot
instance I was trying to run adt-virt-schroot against is as follows:

  [precise-i386-sbuild]
  description=precise-i386-sbuild
  groups=sbuild,root,admin
  root-groups=sbuild,root,admin
  # Uncomment these lines to allow members of these groups to access
  # the -source chroots directly (useful for automated updates, etc).
  source-root-users=sbuild,root,admin
  source-root-groups=sbuild,root,admin
  type=directory
  union-type=overlayfs
  directory=/media/passport/chroot/precise-i386-sbuild
  personality=linux32

adt-virt-schroot chokes on this with:

  Traceback (most recent call last):
    File "/usr/bin/adt-virt-schroot", line 107, in <module>
      parse_args()
    File "/usr/bin/adt-virt-schroot", line 72, in parse_args
      if got_uid == pwd.getpwnam(exp_name).pw_uid
  KeyError: 'getpwnam(): name not found: '

There are two problems here.  Firstly, ''.split(',') returns [''] not
[], so you should filter out empty entries.  Secondly, adt-virt-schroot
should ignore user or group names that don't exist rather than crashing.
Patch attached.

Thanks,

-- 
Colin Watson                                       [cjwat...@ubuntu.com]

>From 61c3d931fc7f8255df7cfefafe4b7434f3f24977 Mon Sep 17 00:00:00 2001
From: Colin Watson <cjwat...@canonical.com>
Date: Tue, 3 Apr 2012 11:06:31 +0100
Subject: [PATCH] Make schroot configuration parsing more robust

Ignore empty root-users/root-groups entries, or entries containing
non-existent users or groups.
---
 virt-subproc/adt-virt-schroot |   29 ++++++++++++++++++++---------
 1 files changed, 20 insertions(+), 9 deletions(-)

diff --git a/virt-subproc/adt-virt-schroot b/virt-subproc/adt-virt-schroot
index 451f254..40384b9 100755
--- a/virt-subproc/adt-virt-schroot
+++ b/virt-subproc/adt-virt-schroot
@@ -37,6 +37,24 @@ sys.path.insert(1, our_base)
 import VirtSubproc as vsp
 capabilities = []
 
+def pw_uid(exp_name):
+	try:
+		return pwd.getpwnam(exp_name).pw_uid
+	except KeyError:
+		return None
+
+def gr_gid(exp_name):
+	try:
+		return grp.getgrnam(exp_name).gr_gid
+	except KeyError:
+		return None
+
+def match(exp_names, ids, extract_id):
+	for exp_name in [n for n in exp_names.split(',') if n]:
+		if extract_id(exp_name) in ids:
+			return True
+	return False
+
 def parse_args():
 	global schroot, debuglevel
 
@@ -66,15 +84,8 @@ def parse_args():
 	if regexp.search('snapshot',cfg['type']):
 		capabilities.append('revert')
 
-	if [True
-		for exp_name in cfg['root-users'].split(',')
-		for got_uid in [os.getuid()]
-		if got_uid == pwd.getpwnam(exp_name).pw_uid
-	] or [True
-		for exp_name in cfg['root-groups'].split(',')
-		for got_gid in [os.getgid()] + os.getgroups()
-		if got_gid == grp.getgrnam(exp_name).gr_gid
-	]:
+	if (match(cfg['root-users'], [os.getuid()], pw_uid) or
+	    match(cfg['root-groups'], [os.getgid()] + os.getgroups(), gr_gid)):
 		capabilities.append('root-on-testbed')
 
 def hook_open():
-- 
1.7.9.1