tieto team mailing list archive

[Launchpad Bug Tracker <1390061@xxxxxxxxxxxxxxxxxx>]

You have been subscribed to a public bug by Ove Risberg (ove-risberg):

1) The release of Ubuntu you are using, via 'lsb_release -rd' or System -> About Ubuntu
root@ubuntu1404:~# lsb_release -rd
Description:    Ubuntu 14.04.1 LTS
Release:        14.04

2) The version of the package you are using, via 'apt-cache policy pkgname' or by checking in Software Center
root@ubuntu1404:~# apt-cache policy bash-completion
bash-completion:
  Installed: 1:2.1-4
  Candidate: 1:2.1-4
  Version table:
 *** 1:2.1-4 0
        500 http://se.archive.ubuntu.com/ubuntu/ trusty/main i386 Packages
        100 /var/lib/dpkg/status

3) What you expected to happen

When I use bash-completion it should not read the /etc/passwd file or contact the Active directory.
It is very hard to see this problem unless you run this on a machine with slow authentication... but the commands below will show if the /etc/passwd or sssd are used by bash_completion or not:

root@ubuntu1404:~# strace bash -c ". /etc/bash_completion; quote_readline '/something'; echo" 2>&1 | grep /etc/passwd
root@ubuntu1404:~# strace bash -c ". /etc/bash_completion; quote_readline '/something'; echo" 2>&1 | grep sss

When the ~ are escaped on line 545 and 547 in /usr/share/bash-
completion/bash_completion then bash_completion works as expected.

4) What happened instead

Every time you use tab-completion in bash on ubuntu 14.04 it will read
the /etc/passwd file and if sssd are installed and configured for Active
Directory authentication it will talk to sssd... and this can be slow in
some environments.

root@ubuntu1404:~# strace bash -c ". /etc/bash_completion; quote_readline '/something'; echo" 2>&1 | grep /etc/passwd
open("/etc/passwd", O_RDONLY|O_CLOEXEC) = 3
root@ubuntu1404:~# strace bash -c ". /etc/bash_completion; quote_readline '/something'; echo" 2>&1 | grep sss
open("/lib/i386-linux-gnu/libnss_sss.so.2", O_RDONLY|O_CLOEXEC) = 3
open("/var/lib/sss/mc/passwd", O_RDONLY|O_LARGEFILE|O_CLOEXEC) = 3
connect(4, {sa_family=AF_LOCAL, sun_path="/var/lib/sss/pipes/nss"}, 110) = 0

I have made a small patch for this problem and I have not found any side effects:
--- /usr/share/bash-completion/bash_completion.orig     2014-11-06 10:36:14.981888369 +0100
+++ /usr/share/bash-completion/bash_completion  2014-11-06 10:36:25.142070963 +0100
@@ -542,9 +542,9 @@
     elif [[ $1 == \'* ]]; then
         # Leave out first character
         printf -v $2 %s "${1:1}"
-    elif [[ $1 == ~* ]]; then
+    elif [[ $1 == \~* ]]; then
         # avoid escaping first ~
-        printf -v $2 ~%q "${1:1}"
+        printf -v $2 \~%q "${1:1}"
     else
         printf -v $2 %q "$1"
     fi

** Affects: bash-completion (Ubuntu)
     Importance: Undecided
         Status: Confirmed

-- 
bash-completion tilde expansion every time
https://bugs.launchpad.net/bugs/1390061
You received this bug notification because you are a member of Tieto, which is subscribed to the bug report.