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List:       oss-security
Subject:    Re: [oss-security] [patch] proc.5: tell how to parse /proc/*/stat correctly
From:       Jakub Wilk <jwilk () jwilk ! net>
Date:       2022-12-30 20:15:54
Message-ID: 20221230201554.xborkqi2x5dvnh6h () jwilk ! net
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* Tavis Ormandy <taviso@gmail.com>, 2022-12-28 01:50:
>>>But, really, I just don't see how this can practically be said to be 
>>>parsable...
>>
>>In its current form it never will be.  The solution is to place this 
>>variable-length field last.  Then you can "cut -d ' ' -f 51-" to get 
>>the command+args part (assuming I counted all those fields correctly 
>>...)
>>
>>Of course, this breaks backwards compatability.
>
>I think that cut command doesn't handle newlines,

Indeed.

>There already is 'ps -q $$ -o >comm='

FWIW, "ps ... -o comm=" doesn't just print the raw comm value: it 
replaces non-printable chars with punctuation characters, and it may 
append " <defunct>" if the process is a zombie.

The easiest way to get unmangled comm is to read it from 
/proc/$PID/comm, then strip the trailing newline.

(But I suspect most /proc/*/stat parsers don't care about the comm field 
at all; they just want to skip over it to get their hands on the 
following fields.)

-- 
Jakub Wilk
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