[ovs-dev] [PATCH] rhel: fix the exit status of the openvswitch init script.
Paul Ingram
pingram at nicira.com
Tue Oct 1 23:17:15 UTC 2013
OK, but I don't see the redirect to descriptor 4 in the real code (it's obviously there in the example).
:: psi
On Oct 1, 2013, at 3:58 PM, Duffie Cooley <dcooley at nicira.com> wrote:
> From the reference.
>
> Lets examine that step by step.
>
> ( ( ( ( someprog; #part6
> echo $? >&3 #part5
> ) | filter >&4 #part4
> ) 3>&1 #part3
> ) | stdintoexitstatus #part2
> ) 4>&1 #part1
> From bottom up:
>
> A subshell is created with file descriptor 4 redirected to stdout. This means that whatever is printed to file descriptor 4 in the subshell will end up as the stdout of the entire construct.
> A pipe is created and the commands on the left (#part3) and right (stdintoexitstatus) are executed. stdintoexitstatus is also the last command of the pipe and that means the exit status of stdintoexitstatus will be the exit status of the entire construct.
> A subshell is created with file descriptor 3 redirected to stdout. This means that whatever is printed to file descriptor 3 in this subshell will end up in stdintoexitstatus and in turn will be the exit status of the entire construct.
> A pipe is created and the commands on the left (#part5 and #part6) and right (filter >&4) are executed. The output of filter is redirected to file descriptor 4. In #part1 the file descriptor 4 was redirected to stdout. This means that the output of filter is the stdout of the entire construct.
> Exit status from #part6 is printed to file descriptor 3. In #part3 file descriptor 3 was redirected tostdintoexitstatus. This means that the exit status from #part6 will be the final exit status for the entire construct.
> someprog is executed. The exit status is taken in #part5. The stdout is taken by the pipe in#part4 and forwarded to filter. The output from filter will in turn reach stdout as explained in#part4
>
>
> On 10/01/2013 03:34 PM, Paul Ingram wrote:
>> Why the redirect from descriptor 4?
>>
>> :: psi
>>
>> On Oct 1, 2013, at 3:13 PM, Duffie Cooley <dcooley at nicira.com> wrote:
>>
>>> What about this?
>>>
>>> referenced from here.
>>>
>>> http://unix.stackexchange.com/questions/14270/get-exit-status-of-process-thats-piped-to-another/70675#70675
>>>
>>> diff --git a/utilities/ovs-lib.in b/utilities/ovs-lib.in
>>> index 1684ddc..5286e12 100644
>>> --- a/utilities/ovs-lib.in
>>> +++ b/utilities/ovs-lib.in
>>> @@ -41,6 +41,11 @@ ovs_ctl_log () {
>>> echo "$@" >> "${logdir}/ovs-ctl.log"
>>> }
>>>
>>> +stdintoexitstatus () {
>>> + read exitstatus
>>> + return $exitstatus
>>> +}
>>> +
>>> ovs_ctl () {
>>> case "$@" in
>>> *"=strace"*)
>>> @@ -51,7 +56,7 @@ ovs_ctl () {
>>> ;;
>>> *)
>>> echo "`date -u`:$@" >> "${logdir}/ovs-ctl.log"
>>> - "${datadir}/scripts/ovs-ctl" "$@" 2>&1 | tee -a
>>> "${logdir}/ovs-ctl.log"
>>> + (((("${datadir}/scripts/ovs-ctl" "$@" 2>&1 ; echo $? > &3)
>>> | tee -a "${logdir}/ovs-ctl.log" ) 3>&1) | stdintoexitstatus) 4>&1
>>> ;;
>>> esac
>>> }
>>>
>>>
>>> Thanks,
>>>
>>> Duffie
>>>
>>>
>>> On 10/01/2013 11:48 AM, Gurucharan Shetty wrote:
>>>> This patch works for me, but it is a little hacky.
>>>>
>>>> diff --git a/utilities/ovs-lib.in b/utilities/ovs-lib.in
>>>> index 1684ddc..b0cdaf2 100644
>>>> --- a/utilities/ovs-lib.in
>>>> +++ b/utilities/ovs-lib.in
>>>> @@ -51,7 +51,13 @@ ovs_ctl () {
>>>> ;;
>>>> *)
>>>> echo "`date -u`:$@" >> "${logdir}/ovs-ctl.log"
>>>> - "${datadir}/scripts/ovs-ctl" "$@" 2>&1 | tee -a
>>>> "${logdir}/ovs-ctl.log"
>>>> + unique=`(uuidgen) 2>/dev/null` || unique=`date +"%Y %b %d %T"`
>>>> + mkfifo "/tmp/${unique}"
>>>> + tee -a "${logdir}/ovs-ctl.log" < "/tmp/${unique}" &
>>>> + "${datadir}/scripts/ovs-ctl" "$@" > "/tmp/${unique}" 2>&1
>>>> + rc=$?
>>>> + rm "/tmp/${unique}"
>>>> + return $rc
>>>> ;;
>>>> esac
>>>> }
>>>>
>>>> On Tue, Oct 1, 2013 at 10:11 AM, Gurucharan Shetty <shettyg at nicira.com> wrote:
>>>>> On Mon, Sep 30, 2013 at 7:27 PM, Duffie Cooley <dcooley at nicira.com> wrote:
>>>>>> From: Duffie Cooley <dcooley at nicira.com>
>>>>>> This is a fix for a request to make sure that the openvswitch status command
>>>>>> in rhel based distros gives a useful exit status. That was fixed in
>>>>>>
>>>>>> commit 5e0c05bc058c78a11be6747f62e6ad88e5d06b70
>>>>>> debian: Fix exit status of openvswitch-switch init script "status" command
>>>>>>
>>>>>>
>>>>>>
>>>>>> Signed-off-by: Duffie Cooley <dcooley at nicira.com>
>>>>>> ---
>>>>>> rhel/etc_init.d_openvswitch | 3 ++-
>>>>>> 1 file changed, 2 insertions(+), 1 deletion(-)
>>>>>>
>>>>>> diff --git a/rhel/etc_init.d_openvswitch b/rhel/etc_init.d_openvswitch
>>>>>> index 7e64132..6a53cef 100755
>>>>>> --- a/rhel/etc_init.d_openvswitch
>>>>>> +++ b/rhel/etc_init.d_openvswitch
>>>>>> @@ -5,7 +5,7 @@
>>>>>> # chkconfig: 2345 09 91
>>>>>> # description: Manage Open vSwitch kernel modules and user-space daemons
>>>>>>
>>>>>> -# Copyright (C) 2009, 2010, 2011 Nicira, Inc.
>>>>>> +# Copyright (C) 2009, 2010, 2011, 2013 Nicira, Inc.
>>>>>> #
>>>>>> # Licensed under the Apache License, Version 2.0 (the "License");
>>>>>> # you may not use this file except in compliance with the License.
>>>>>> @@ -81,6 +81,7 @@ case $1 in
>>>>>> ;;
>>>>>> status)
>>>>>> ovs_ctl status
>>>>>> + exit $?
>>>>>> ;;
>>>>>> version)
>>>>>> ovs_ctl version
>>>>>> --
>>>>>> 1.8.1.2
>>>>>>
>>>>> I don't think this helps. The exit status is always 0. I broke this
>>>>> with my implementation of 'ovs_ctl' in ovs-lib tee'ing the o/p to
>>>>> ovs-ctl.log. tee will return an exit status of success even though the
>>>>> previous command returned an exit status of 1.
>>>>>
>>>>> I can use the PIPESTATUS variable. But I don't think it is POSIX
>>>>> compliant. Any other ideas?
>>>>>
>>> _______________________________________________
>>> dev mailing list
>>> dev at openvswitch.org
>>> http://openvswitch.org/mailman/listinfo/dev
>
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