[Sugar-devel] "Another osbuild instance is running" error

[Shraddha Barke]

On Sat, 2 Jan 2016, James Cameron wrote:

> On Sat, Jan 02, 2016 at 10:21:12AM +0530, Shraddha Barke wrote:
>>
>>
>> On Sat, 2 Jan 2016, James Cameron wrote:
>>
>>> On Fri, Jan 01, 2016 at 08:38:34PM +0530, Shraddha Barke wrote:
>>>>
>>>>
>>>> On Fri, 1 Jan 2016, James Cameron wrote:
>>>>
>>>>> On Thu, Dec 31, 2015 at 11:26:26PM +0530, Shraddha Barke wrote:
>>>>>>
>>>>>>
>>>>>> On Thu, 31 Dec 2015, James Cameron wrote:
>>>>>>
>>>>>>> On Thu, Dec 31, 2015 at 03:38:02AM +0530, Shraddha Barke wrote:
>>>>>>>>> On Wed, Dec 30, 2015 at 04:30:17AM +0530, Shraddha Barke wrote:
>>>>>>>>>> I am trying to build sugar on Ubuntu 15.04 laptop. After git clone
>>>>>>>>>> and cd into sugar-build I get this error-Another osbuild instance is
>>>>>>>>>> running on executing ./osbuild pull
>>>>>>>>>> I searched the internet and found 2 such threads but the issue wasn't
>>>>>>>>>> resolved.
>>>>>>>>>
>>>>>>>>> There's more than two such threads on sugar-devel at .
>>>>>>>>>
>>>>>>>>>> Is this a bug that needs fixing?
>>>>>>>>>
>>>>>>>>> Yes, it's a bug in osbuild, please fix it.
>>>>>>>>
>>>>>> Hello James,
>>>>>> I made the following changes in check_lock()
>>>>>>
>>>>>> def check_lock():
>>>>>> -    try:
>>>>>> -        fcntl.lockf(get_lock_file(), fcntl.LOCK_EX | fcntl.LOCK_NB)
>>>>>> -    except IOError:
>>>>>> -        return False
>>>>>> -
>>>>>> -    return True
>>>>>> -
>>>>>>
>>>>>> +       pid = os.getpid()
>>>>>> +       try:
>>>>>> +            fcntl.lockf(pid, fcntl.LOCK_EX | fcntl.LOCK_NB)
>>>>>> +       except IOError:
>>>>>> +           return False
>>>>>> +       try:
>>>>>> +           os.kill(pid(), 0)
>>>>>> +       except OSError:
>>>>>> +            return False
>>>>>> +        return True
>>>>>
>>>>> Ah, that's not what I meant.
>>>>>
>>>>> But I was wrong to suggest a redesign using getpid and kill, because
>>>>> my analysis of the code _today_ shows the underlying cause must be
>>>>> something other than locking.
>>>>>
>>>>> Let me explain.
>>>>>
>>>>> check_lock does try fcntl.lock, and if an exception IOError occurs,
>>>>> does return False.
>>>>>
>>>>> But inside the same try clause is a call to get_lock_file.  Therefore
>>>>> any IOError inside get_lock_file will also cause check_lock to return
>>>>> False.
>>>>>
>>>>> A possible error is that the file could not be opened for write,
>>>>> e.g. because it is owned by someone else, or the protection mask
>>>>> (chmod) is wrong, or the directory does not exist, or the directory is
>>>>> protected.
>>>>>
>>>>> def check_lock():
>>>>>  lock_file = get_lock_file()
>>>>>  try:
>>>>>      fcntl.lockf(lock_file, fcntl.LOCK_EX | fcntl.LOCK_NB)
>>>>>  except IOError:
>>>>>      return False
>>>>>
>>>>>  return True
>>>>>
>>>>> As a result of this change, any problem opening and writing to the
>>>>> file will be reported before the "another instance" error.
>>>>>
>>>>
>>>> Ah Got it! Thanks :)
>>>>
>>>> Like you said it's a permission error. I've posted it below -
>>>>
>>>> Traceback (most recent call last):
>>>>  File "./osbuild", line 504, in <module>
>>>>    if not main():
>>>>  File "./osbuild", line 467, in main
>>>>    if not check_lock():
>>>>  File "./osbuild", line 406, in check_lock
>>>>    lock_file = get_lock_file()
>>>>  File "./osbuild", line 90, in get_lock_file
>>>>    lock_file = open(get_lock_file_path(), "w")
>>>> IOError: [Errno 13] Permission denied:
>>>> '/home/shraddha/git/sugar-build/.lock-host'
>>>
>>> Okay, that will certainly stop osbuild from working.
>>>
>>>>
>>>>>>
>>>>>> so that when there is no process running false is returned. However it is
>>>>>> not fixing the bug.
>>>>>> And yeah when I try to delete the lock file, I get 'file or
>>>>>> directory doesn't exist'
>>>>>
>>>>> That's not possible to explain given the data you sent.
>>>>>
>>>>> You said the print statement showed the file path as
>>>>>
>>>>> .../git/sugar-build/.lock-host
>>>>>
>>>>> Presumably ... is something like /home/username
>>>>>
>>>>> Does the .lock-host file still exist?
>>>>>
>>>>> Show me "stat .lock-host"?
>>>>>
>>>>> If the file exists, but you cannot delete it, then osbuild will fail
>>>>> to open it for write.
>>>>>
>>>>
>>>> stat: cannot stat ‘.lock-host’: No such file or directory
>>>>
>>>> This is what I get. It's confusing that although it's failing to write,
>>>> stat says no such directory exists!
>>>
>>> Ye, that is strange.  On the one hand the file exists and cannot be
>>> opened for write, yet now the file does not exist.
>>>
>>> Please check you are in the right directory when you use stat, or use
>>> stat with the same full path to the file (as reported by osbuild);
>>>
>>> 	stat /home/shraddha/git/sugar-build/.lock-host
>>>
>>> I'm trying not to presume any knowledge; if you only type "stat
>>> .lock-host", then the stat program will look for the file .lock-host
>>> in the current directory.  You can see what the current directory is
>>> by typing "pwd".  You can change the current directory using the "cd"
>>> command.
>>
>>
>> stat: cannot stat ‘/home/shraddha/git/sugar-build/.lock-host’: No
>> such file or directory
>>
>> I'm searching why this is happening. Meanwhile if anything strikes you
>> do let me know
>
> Since the open does fail, and yet the file does not exist, the problem
> must be in creating the file.
>
> The most likely cause is owner or protection mask of the directory;
> the directory in which the file is to be created, so please check:
>
> 	stat /home/shraddha/git/sugar-build
>
> Example expected output;
>
>  File: ‘/home/use/git/sugar-build’
>  Size: xxxxx           Blocks: xx         IO Block: xxxx   directory
> Device: xxxh/xxxxd      Inode: xxxxxxxx    Links: xxx
> Access: (0755/drwxr-xr-x)  Uid: ( 1000/   user)   Gid: ( 1000/   user)
> Access: 2016-01-02 17:15:56.881528661 +1100
> Modify: 2016-01-02 17:14:19.290923184 +1100
> Change: 2016-01-02 17:14:19.290923184 +1100


Okay so when I try stat I get the output. This is because I had cloned 
with root

File: ‘/home/shraddha/git/sugar-build’
   Size: 4096      	Blocks: 8          IO Block: 4096   directory
Device: 805h/2053d	Inode: 5112265     Links: 5
Access: (0755/drwxr-xr-x)  Uid: (    0/    root)   Gid: (    0/    root)
Access: 2016-01-02 12:22:17.908837058 +0530
Modify: 2016-01-02 12:22:34.796837546 +0530
Change: 2016-01-02 12:22:34.796837546 +0530
  Birth: -

I deleted the file and again cloned without root which gives me-

   File: ‘/home/shraddha/git/sugar-build’
   Size: 4096      	Blocks: 8          IO Block: 4096   directory
Device: 805h/2053d	Inode: 5112265     Links: 5
Access: (0775/drwxrwxr-x)  Uid: ( 1000/shraddha)   Gid: ( 1000/shraddha)
Access: 2016-01-02 12:10:22.968816395 +0530
Modify: 2016-01-02 12:13:37.952822030 +0530
Change: 2016-01-02 12:13:37.952822030 +0530
Birth: -

>
> Also tell me your process uid and gid, by typing:
>
> 	id
>
> Example expected output;
>
> uid=1000(user) gid=1000(user) groups=1000(user)

uid=1000(shraddha) gid=1000(shraddha) 
groups=1000(shraddha),4(adm),24(cdrom),27(sudo),30(dip),46(plugdev),115(lpadmin),131(sambashare)

This is the output without root.
And when I run ./osbuild I get:

usage: osbuild [-h]
                {dist,build,karma,docs,check,shell,run,clean,pull,broot} 
...
osbuild: error: too few arguments

Kind Regards,
Shraddha
>
> -- 
> James Cameron
> http://quozl.netrek.org/
>