Bug#413249: severity of 413249 is important, tagging 413249
Steve Langasek [EMAIL PROTECTED] wrote:
# Automatically generated email from bts, devscripts version 2.9.27
severity 413249 important
tags 413249 unreproducible
It is very well reproducible here, it occurred again today. This time,
even Ctrl-c wouldn't stop the script, it ate 95% CPU, and ps axf
showed that it had somehow detached from the controlling X terminal. It
needed a kill $pid to get control of my CPU.
I have added a set -x in config and preinst, and this showed me one
point were there is a bug in the config script. I am not sure, however,
that this is the root of my problem.
The bug I found so far is
while :; do
run db_input low x11-common/xwrapper/nice_value
# is the question going to be asked?
if [ $? -eq 30 ]; then
break # no; bail out of validation loop
fi
Because db_input is wrapped in the run function, the return value of
db_input is no longer in $?, and the script will not break the loop. It
is in $_retval, though:
run () {
[...]
$@ || _retval=$?
if [ ${_retval:-0} -ne 0 ]; then
observe command \$*\ exited with status $_retval
fi
The patch for this would be
while :; do
run db_input low x11-common/xwrapper/nice_value
# is the question going to be asked?
+ WILL_BE_ASKED=$_retval
- if [ $? -eq 30 ]; then
+ if [ $WILL_BE_ASKED -eq 30 ]; then
break # no; bail out of validation loop
fi
However, changing this doesn't fix my problem, and I got sceptical
whether it originates in x11-common, since I get so many internal
debconf errors.
I removed the content of /var/cache/debconf, dpkg-reconfigure'd debconf,
and tried again, but that didn't help.
Somehow still debconf's answers are not what the config script expects.
Upon reinstalling x11-common with set -xv, I get
# next question requires input validation; assume safe valid value already
# present (possibly the template default)
SAFE=
+ SAFE=
if db_get x11-common/xwrapper/nice_value; then
SAFE=$RET
fi
+ db_get x11-common/xwrapper/nice_value
+ _db_cmd 'GET x11-common/xwrapper/nice_value'
+ IFS=' '
+ printf '%s\n' 'GET x11-common/xwrapper/nice_value'
debconf (developer): -- GET x11-common/xwrapper/nice_value
debconf (developer): -- 0 0
+ IFS='
'
+ read -r _db_internal_line
+ RET='value set'
+ case ${_db_internal_line%%[ ]*} in
+ return 0
+ SAFE='value set'
Why on earth is $RET now value set, where it should be 0? Note
that value set was the last answer that debconf communicated about
that template, but not the last answer it communcated in that script
(which was about allowed_users.
What is happening here? Please remember that this is an etch system
installed on the 10th of February, nothing were the system had time to
degrade into a mess of distribution mixture and local misconfiguration
(though I do not exclude the latter...)
Regards, Frank
--
Dr. Frank Küster
Single Molecule Spectroscopy, Protein Folding @ Inst. f. Biochemie, Univ. Zürich
Debian Developer (teTeX/TeXLive)
Bug#413249: severity of 413249 is important, tagging 413249
clone 413249 -1
retitle 413249 wrong returnvalue logic in config script
tags 413249 -unreproducible
retitle -1 debconf: database communication does not work
reassign -1 debconf
thanks
Frank Küster [EMAIL PROTECTED] wrote:
It is very well reproducible here, it occurred again today.
[...]
The bug I found so far is
(this is going to stay 413249, package x11-common)
while :; do
run db_input low x11-common/xwrapper/nice_value
# is the question going to be asked?
if [ $? -eq 30 ]; then
break # no; bail out of validation loop
fi
Because db_input is wrapped in the run function, the return value of
db_input is no longer in $?, and the script will not break the loop. It
is in $_retval, though:
run () {
[...]
$@ || _retval=$?
if [ ${_retval:-0} -ne 0 ]; then
observe command \$*\ exited with status $_retval
fi
The patch for this would be
while :; do
run db_input low x11-common/xwrapper/nice_value
# is the question going to be asked?
+ WILL_BE_ASKED=$_retval
- if [ $? -eq 30 ]; then
+ if [ $WILL_BE_ASKED -eq 30 ]; then
break # no; bail out of validation loop
fi
However, changing this doesn't fix my problem, and I got sceptical
whether it originates in x11-common, since I get so many internal
debconf errors.
This is why I reassign the other part of this to debconf. I'm quite
sure that what is going on on my system is not a general breakage of
debconf, but for sure it is something that needs investigation
[work on debconf snipped, see bug log]
debconf (developer): -- GET x11-common/xwrapper/nice_value
debconf (developer): -- 0 0
+ IFS='
'
+ read -r _db_internal_line
[...]
Why on earth is $RET now value set, where it should be 0? Note
that value set was the last answer that debconf communicated about
that template, but not the last answer it communcated in that script
(which was about allowed_users.
Now the debug output below adds to the confusion, but it might be easier
to debug. I have done
# dpkg --purge --force-depends x11-common
and then installed again, with set -xv in the maintainer scripts.
Things to observe:
- db_set returns with exit code 1. Is this okay? I think it
shouldn't, and it's a peculiarity of x11-common to not stop when this
happens. However, what does it indicate on the debconf side?
- after the skipped parts, the db_input part is not interesting, but
shows that that goes without errors
- db_go gives an internal debconf error (I have just apt-get
--reinstall install'ed the etch version, so the files should be okay)
- db_get returns *nothing*, although it was set to 0 earlier.
+ run db_set x11-common/xwrapper/nice_value 0
+ '[' 3 -lt 1 ']'
+ db_set x11-common/xwrapper/nice_value 0
+ _db_cmd 'SET x11-common/xwrapper/nice_value' 0
+ IFS=' '
+ printf '%s\n' 'SET x11-common/xwrapper/nice_value 0'
debconf (developer): -- SET x11-common/xwrapper/nice_value 0
debconf (developer): -- 0 value set
+ IFS='
'
+ read -r _db_internal_line
+ RET='value set'
+ case ${_db_internal_line%%[ ]*} in
+ return 0
+ '[' 1 -ne 0 ']'
+ observe 'command db_set x11-common/xwrapper/nice_value 0 exited with status
1'
+ '[' -n '' ']'
[... some parts skipped ...]
+ run db_input low x11-common/xwrapper/nice_value
+ '[' 3 -lt 1 ']'
+ db_input low x11-common/xwrapper/nice_value
+ _db_cmd 'INPUT low' x11-common/xwrapper/nice_value
+ IFS=' '
+ printf '%s\n' 'INPUT low x11-common/xwrapper/nice_value'
+ IFS='
'
+ read -r _db_internal_line
debconf (developer): -- INPUT low x11-common/xwrapper/nice_value
debconf (developer): -- 30 question skipped
+ RET='30 question skipped'
+ case ${_db_internal_line%%[ ]*} in
+ return 30
+ _retval=30
+ '[' 30 -ne 0 ']'
+ observe 'command db_input low x11-common/xwrapper/nice_value exited with
status 30'
+ '[' -n '' ']'
+ '[' 0 -eq 30 ']'
+ run db_go
+ '[' 1 -lt 1 ']'
+ db_go
+ _db_cmd 'GO '
+ IFS=' '
+ printf '%s\n' 'GO '
+ IFS='
'
+ read -r _db_internal_line
debconf (developer): -- GO
Use of uninitialized value in join or string at
/usr/share/perl5/Debconf/DbDriver/Stack.pm line 104, GEN1 line 7.
debconf (developer): -- 0 ok
+ RET=ok
+ case ${_db_internal_line%%[ ]*} in
+ return 0
+ '[' 30 -ne 0 ']'
+ observe 'command db_go exited with status 30'
+ '[' -n '' ']'
+ RET=
+ db_get x11-common/xwrapper/nice_value
+ _db_cmd 'GET x11-common/xwrapper/nice_value'
+ IFS=' '
+ printf '%s\n' 'GET x11-common/xwrapper/nice_value'
+ IFS='
'
+ read -r _db_internal_line
debconf (developer): -- GET x11-common/xwrapper/nice_value
debconf (developer): -- 0
+ RET=
Any idea what's going on?
Regards, Frank
--
Dr. Frank Küster
Single Molecule Spectroscopy, Protein Folding @ Inst. f. Biochemie, Univ. Zürich
Debian Developer (teTeX/TeXLive)
Bug#413249: severity of 413249 is important, tagging 413249
On Mon, Mar 05, 2007 at 02:02:07PM +0100, Frank Küster wrote:
I removed the content of /var/cache/debconf, dpkg-reconfigure'd debconf,
and tried again, but that didn't help.
Somehow still debconf's answers are not what the config script expects.
Upon reinstalling x11-common with set -xv, I get
# next question requires input validation; assume safe valid value already
# present (possibly the template default)
SAFE=
+ SAFE=
if db_get x11-common/xwrapper/nice_value; then
SAFE=$RET
fi
+ db_get x11-common/xwrapper/nice_value
+ _db_cmd 'GET x11-common/xwrapper/nice_value'
+ IFS=' '
+ printf '%s\n' 'GET x11-common/xwrapper/nice_value'
debconf (developer): -- GET x11-common/xwrapper/nice_value
debconf (developer): -- 0 0
+ IFS='
'
+ read -r _db_internal_line
+ RET='value set'
+ case ${_db_internal_line%%[ ]*} in
+ return 0
+ SAFE='value set'
Why on earth is $RET now value set, where it should be 0?
Good question. What does 'debconf-show x11-common' spit out at this point?
--
Steve Langasek Give me a lever long enough and a Free OS
Debian Developer to set it on, and I can move the world.
[EMAIL PROTECTED] http://www.debian.org/
Bug#413249: severity of 413249 is important, tagging 413249
On Tuesday 06 March 2007 03:58, Steve Langasek wrote: Why on earth is $RET now value set, where it should be 0? Good question. What does 'debconf-show x11-common' spit out at this point? I would guess that the error is in the code that _sets_ the value of this debconf question. I'm fairly certain that value set is what is returned in $RET by the db_set command (together with an error code of 0). In general in debconf, $RET can contain error or informational messages from debconf itself as well as real values, roughly as follows: - error code 0: $RET = error message - error code = 0 and function should return a real value (e.g. db_get): $RET = real value - error code =0 and function does not return a real value (e.g. db_set or db_go): $RET = informational message This means that with incorrect error handling, or by executing a db_* function without saving the value of $RET in a different variable before reusing $RET, you can end up with these kind of values. Hope this helps. Cheers, FJP pgp4LU74JW8Yk.pgp Description: PGP signature
