Re: Suggestion for clarifications on "man 5 proc" page regarding /proc/[pid]/self race conditions

[Alejandro Colomar <alx@kernel.org>]

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Dear ellie, Petr,

On Tue, Dec 12, 2023 at 09:47:58AM +0100, ellie wrote:
> Dear Alejandro Colomar,
> 
> I hope I'm emailing this to the correct place, I found this contact
> information on https://man7.org/mtk/contact.html regarding man page
> feedback:

Yep, this is the correct place.

Petr, Michael retired from maintaining the project a couple of years
ago.  As Michael says in <https://www.man7.org/mtk/contact.html>,
reports about the Linux man-pages should be reported to this mailing
list, following the ./CONTRIBUTING file
<https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/CONTRIBUTING>.

> 
> I'm suggesting that the "man 5 proc" page is expanded with a section

I've recently splitted the proc(5) page into many small pages, one for
each file or directory.  You may want to check the current manual pages.
You can do that by reading directly from the repository, or by reading
the PDF book (thanks to Deri James, from gropdf(1), for contributing the
scripts to produce the book).

To check the book as of the latest commit in git HEAD, you can check
<https://www.alejandro-colomar.es/share/dist/man-pages/git/HEAD/man-pages-HEAD.pdf>

You will probably want to check proc_self(5) --which is a link page; the
text is actually in proc_pid(5)--.  proc(5) still contains some small
mention of /proc/self, so you'll want to check that too.

> clarifying /proc/[pid]/self

You probably mean /proc/self/, or /proc/[pid]/.

> race conditions, I described details and even
> made a text suggestion here:
> 
> https://bugzilla.suse.com/show_bug.cgi?id=1216352

After seeing the suggestion, you'll want to check proc_pid_exe(5):

<https://www.alejandro-colomar.es/share/dist/man-pages/git/HEAD/man-pages-HEAD.pdf#proc_pid_exe.5>

You could add a CAVEATS section in that page.  Please write also a test
program that reproduces the race condition, and another one which
demonstrates how your solution doesn't.  Those test programs will be
useful to include in the commit message.

> (The text suggestion might be wrong, however, since I don't actually know
> what the exact technical state of this is.)

It looks good.  With a small example program that demonstrates it,
you'll be able to answer your doubts.  ;-)

Have a lovely day!
Alex

-- 
<https://www.alejandro-colomar.es/>
Looking for a remote C programming job at the moment.

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