[PATCH 04/15] prlimit: add warning diagnostic when attempting to change prlimit's limits

[PATCH 04/15] prlimit: add warning diagnostic when attempting to change prlimit's limits

[Bernhard Voelker]

[PATCH 04/15] prlimit: add warning diagnostic when attempting to change 
prlimit's limits

Setting the limits of the prlimit process is useless because it will
exit shortly anyway. To help the user not to fall into this trap,
prlimit now displays a warning.

Signed-off-by: Bernhard Voelker <mail@bernhard-voelker.de>
---
  sys-utils/prlimit.c |    7 +++++--
  1 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/sys-utils/prlimit.c b/sys-utils/prlimit.c
index 6943d11..9a52b81 100644
--- a/sys-utils/prlimit.c
+++ b/sys-utils/prlimit.c
@@ -302,10 +302,13 @@ static void do_prlimit(struct prlimit lims[], 
size_t n, int tt_flags)
  	for (i = 0; i < n; i++) {
  		struct rlimit *new = NULL;

-		if (lims[i].modify)
+		if (lims[i].modify) {
+			if (!pid)
+				warnx(_("setting limits of the prlimit process is pointless"));
  			new = &lims[i].rlim;
-		else
+		} else {
  			nshows++;
+		}

  		if (verbose && new) {
  			printf(_("New %s limit: "), lims[i].desc->name);

Re: [PATCH 04/15] prlimit: add warning diagnostic when attempting to change prlimit's limits

[Karel Zak]

On Mon, Nov 14, 2011 at 02:48:11AM +0100, Bernhard Voelker wrote:
> +		if (lims[i].modify) {
> +			if (!pid)
> +				warnx(_("setting limits of the prlimit process is pointless"));

 Well, I don't think that we want such warnings in our utils :-) Let's
 inform users about errors, the rest should be described in man pages.

 Anyway, it would be nice to have something like:

    prlimit --nofile=1000 /bin/program

 so somewhere after show_limits() should be exec().
    
        Karel

-- 
 Karel Zak  <kzak@redhat.com>
 http://karelzak.blogspot.com

Re: [PATCH 04/15] prlimit: add warning diagnostic when attempting to change prlimit's limits

[Bernhard Voelker]

On 11/16/2011 01:45 PM, Karel Zak wrote:

>   Anyway, it would be nice to have something like:
>
>      prlimit --nofile=1000 /bin/program
>
>   so somewhere after show_limits() should be exec().

Great idea. ;-)
Would you like me to give it a try?

Have a nice day,
Berny

Re: [PATCH 04/15] prlimit: add warning diagnostic when attempting to change prlimit's limits

[Karel Zak]

On Wed, Nov 16, 2011 at 04:05:10PM +0100, Bernhard Voelker wrote:
> On 11/16/2011 01:45 PM, Karel Zak wrote:
>
>>   Anyway, it would be nice to have something like:
>>
>>      prlimit --nofile=1000 /bin/program
>>
>>   so somewhere after show_limits() should be exec().
>
> Great idea. ;-)
> Would you like me to give it a try?

 Sure, go ahead!

    Karel

-- 
 Karel Zak  <kzak@redhat.com>
 http://karelzak.blogspot.com

Re: [PATCH 04/15] prlimit: add warning diagnostic when attempting to change prlimit's limits

[Bernhard Voelker]

On 11/16/2011 01:45 PM, Karel Zak wrote:
> On Mon, Nov 14, 2011 at 02:48:11AM +0100, Bernhard Voelker wrote:
>> >  +		if (lims[i].modify) {
>> >  +			if (!pid)
>> >  +				warnx(_("setting limits of the prlimit process is pointless"));
>
>   Well, I don't think that we want such warnings in our utils:-)  Let's
>   inform users about errors, the rest should be described in man pages.

hmm, then I tend to make it an error: prlimit acts too similar to
ulimit, but the *big* difference - and therefore the *big* trap for
the user - is that ulimit is a shell builtin which affects the current
shell process whereas prlimit runs in it's own process and, as a result,
will just do not have an effect without a PID.

Have a nice day,
Berny