Date: Sat, 12 Oct 1996 10:15:54 +0200 From: Poul-Henning Kamp <phk@critter.tfs.com> To: Gary Jennejohn <Gary.Jennejohn@munich.netsurf.de> Cc: freebsd-current@FreeBSD.org Subject: Re: invalid return value from sysctl_kern_proc ? Message-ID: <3180.845108154@critter.tfs.com> In-Reply-To: Your message of "Fri, 11 Oct 1996 23:04:19 -0000." <199610112304.XAA06498@peedub.gj.org>
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In message <199610112304.XAA06498@peedub.gj.org>, Gary Jennejohn writes:
>Poul-Henning Kamp writes:
>>In message <199610111957.TAA05925@peedub.gj.org>, Gary Jennejohn writes:
>[cruft deleted]
>>>I ask because sysctl isn't returning an error when I try to get the proc
>>>struct for a non-existent process. Seems to me that it should.
>>
>>Well, it does, you don't get any data back.
>>
>>sysctl doesn't return error for things in the data domain it handles,
>>only errors about the handling.
>>
>
>thanks alot, Poul-Henning !
>
>this means that this code from kvm_getprocs in libkvm is wrong.
>
> if (size % sizeof(struct kinfo_proc) != 0) {
> _kvm_err(kd, kd->program,
> "proc size mismatch (%d total, %d chunks)",
> size, sizeof(struct kinfo_proc));
> return (0);
> }
>
>sysctl will set size = 0 if it can't find the requested data. This should
>probably read
>
> if (!size || size % sizeof(struct kinfo_proc) != 0) {
> ^^^^^^^
>
>I used the code from libkvm, which didn't work as I expected it to.
No, that would be wrong. You would get the "proc size mismatch" message
then for the case of "process not found" that would be wrong.
--
Poul-Henning Kamp | phk@FreeBSD.ORG FreeBSD Core-team.
http://www.freebsd.org/~phk | phk@login.dknet.dk Private mailbox.
whois: [PHK] | phk@ref.tfs.com TRW Financial Systems, Inc.
Future will arrive by its own means, progress not so.
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