Date: Thu, 19 Nov 2009 14:45:05 +0100 From: Attilio Rao <attilio@freebsd.org> To: Robert Watson <rwatson@freebsd.org> Cc: freebsd-current@freebsd.org, Ed Maste <emaste@freebsd.org> Subject: Re: [PATCH] Let gcore use ptrace interface rather than the procfs Message-ID: <3bbf2fe10911190545l264c0e2s615034999f46bc0a@mail.gmail.com> In-Reply-To: <alpine.BSF.2.00.0911190757430.12162@fledge.watson.org> References: <3bbf2fe10911160718j7784b311g2980aa02c79bc9ec@mail.gmail.com> <alpine.BSF.2.00.0911171120050.47035@fledge.watson.org> <20091117141713.GA51251@sandvine.com> <9C740225-CB30-4D26-8E4B-F9D5DC51B899@FreeBSD.org> <3bbf2fe10911181733j598083feiddf3d4b34d0007d6@mail.gmail.com> <alpine.BSF.2.00.0911190757430.12162@fledge.watson.org>
next in thread | previous in thread | raw e-mail | index | archive | help
2009/11/19 Robert Watson <rwatson@freebsd.org>: > > On Thu, 19 Nov 2009, Attilio Rao wrote: > >> 2009/11/17 Robert N. M. Watson <rwatson@freebsd.org>: >>> >>> On 17 Nov 2009, at 14:17, Ed Maste wrote: >>> >>>> Our original motivation for doing this was to make gcore work with >>>> threaded apps, not avoiding procfs, but that's a useful side-effect of the >>>> work. Note though that for that purpose it isn't complete; procfs is still >>>> used in readmap to read the process' memory map. It looks like we need to >>>> find a way to implement readmap without procfs. >>> >>> Are the sysctls used for procstat -v sufficient for this purpose? >> >> This patch should address the arised concerns by both of you: >> http://www.freebsd.org/~attilio/Sandvine/STABLE_8/gcore/gcore2.diff >> >> and additively fix elf_getstatus() to not use procfs, so that gcore is >> completely procfs independent now. Comments, reviews and testing are >> welcome. > > If you add the missing include of sys/wait.h, elfcore.c generates an error > instead of a warning on this non-traditional use of wait(2): > > + wait(); > > Something like this may be preferred: > > if (waitpid(pid, NULL, 0) < 0) > err(1, "waitpid"); I didn't get a warning neither an error but yes, the waitpid() is preferred and should be used. > This further persisting reference to procfs can be replaced with a > sysctl/kvm interface: > > gcore.c: asprintf(&binfile, "/proc/%d/file", pid); Right, I just modified elfcore so I missed it. > See the implementation of "procstat -b" which returns the path to the binary > using the same underlying mechanism (vn_fullpath on the process image > vnode). > > I think that kills the last of the procfs dependencies, in which case > perhaps we can remove the procfs.h include from elfcore.c, which requires > defining a local version of a summary data structure borrowed from procfs. > It's worth trying with procfs unmounted, however, to make sure they're > really all gone (which is how I ran into the above problem). I don't like the idea to replicate the structures because of code maintence. IMHO is ok to have procfs header. I will provide ASAP a new patch which addresses this concerns and testing without procfs mounted. Thanks, Attilio -- Peace can only be achieved by understanding - A. Einstein
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?3bbf2fe10911190545l264c0e2s615034999f46bc0a>