Date: Wed, 23 Jan 2013 09:25:00 +0200 From: Mikolaj Golub <trociny@freebsd.org> To: Stanislav Sedov <stas@freebsd.org> Cc: freebsd-hackers@freebsd.org, Robert Watson <rwatson@freebsd.org> Subject: Re: libprocstat(3): retrieve process command line args and environment Message-ID: <20130123072459.GA48402@gmail.com> In-Reply-To: <9679EEE4-BE52-493E-9188-CAECEE5E63D3@freebsd.org> References: <20130119151253.GB88025@gmail.com> <201301221201.06290.jhb@freebsd.org> <20130122211743.GA4490@gmail.com> <201301221648.50747.jhb@freebsd.org> <9679EEE4-BE52-493E-9188-CAECEE5E63D3@freebsd.org>
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On Tue, Jan 22, 2013 at 02:17:39PM -0800, Stanislav Sedov wrote: > > On Jan 22, 2013, at 1:48 PM, John Baldwin <jhb@freebsd.org> wrote: > > > > Well, you could make procstat open a kvm handle in both cases (open a "live" > > handle in the procstat_open_sysctl() case). It just seems rather silly to be > > duplicating code in the two interfaces. In this particular case I prefer code duplication to opening a kvm handle in procstat_open_sysctl(), as it looks a bit confusing. But I can do this way if the agreement is reached. > > More a question for Robert: does > > libprocstat intentionally duplicate the code in libkvm for other things as > > well in the live case? (Like fetching the list of processes?) > > > It does not actually has a duplicate code, the code for fetching the list of > processes via sysctl is different from the KVM case. The open file descriptors > processing is different as well. Because libprocstat implements almost the > same functionality both for sysctl and mvm backends, it can be used to analyze > both the live system and the kernel crash dumps. The code Mikolaj proposed > only implements the sysctl backend currently, so it does not seem to have > any relation to KVM, so it will be a bit weird to make it open a KVM handle > though it does not use it. IMHO, after adding procstat_getargv and procstat_getargv, the usage of kvm_getargv() and kvm_getenvv() (at least in the new code) may be deprecated. As this is stated in the man page, BUGS section, "these routines do not belong in the kvm interface". I suppose they are part of libkvm because there was no a better place for them. procstat(1) prefers direct sysctl to them (so, again, code duplication, which I am going to remove adding procstat_getargv/envv). -- Mikolaj Golub
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