Originally submitted by vkoukis as issue 23:

What steps will reproduce the problem?

1. Do this inside Python:
   import setproctitle; setproctitle.setproctitle('exec arg1 arg2')

What is the expected output? What do you see instead?
Everything looks ok in ps:

vkoukis 32321 32287 3 12:54 pts/3 00:00:00 exec arg1 arg2

But not in /proc/32321/cmdline:
$ cat /proc/32321/cmdline
exec arg1 arg2

The problem is that arguments should be separated from the actual name of the executable by NUL bytes, e.g.:

$ hexdump -vC /proc/32137/cmdline
00000000 2f 75 73 72 2f 73 62 69 6e 2f 61 70 61 63 68 65 |/usr/sbin/apache|
00000010 32 00 2d 6b 00 73 74 61 72 74 00 |2.-k.start.|
0000001b

Otherwise one cannot tell apart the name of the executable from the rest of the arguments.

When trying to use NUL bytes expicitly:

In [7]: setproctitle.setproctitle('exec\x00arg1\x00')

TypeError Traceback (most recent call last)

/home/vkoukis/<ipython console> in <module>()

TypeError: argument 1 must be string without null bytes, not str

What version of the product are you using? On what operating system?

I am using the package that comes with Debian Squeeze:

$ dpkg -l python-setproctitle
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Name Version Description
+++-=====================-=====================-==========================================================
ii python-setproctitle 1.0.1-1 A setproctitle implementation for Python

Please provide any additional information below.

I think it would make sense to support setting the names of command-line arguments explicitly, either by supporting an arbitrary number of arguments, e.g. setproctitle('exec', 'arg1', 'arg2'), or by allowing NUL bytes inside the string.