Date: Mon, 29 Aug 2016 21:04:54 +0300 From: Konstantin Belousov <kostikbel@gmail.com> To: John Baldwin <jhb@freebsd.org> Cc: Andrey Chernov <ache@freebsd.org>, src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r304928 - in head/lib/libc: amd64/sys i386/sys sys Message-ID: <20160829180454.GU83214@kib.kiev.ua> In-Reply-To: <18206408.GMLM77D01s@ralph.baldwin.cx> References: <201608272303.u7RN3N0D078505@repo.freebsd.org> <1595604.93PBdSz0kX@ralph.baldwin.cx> <20160829065813.GP83214@kib.kiev.ua> <18206408.GMLM77D01s@ralph.baldwin.cx>
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On Mon, Aug 29, 2016 at 09:51:50AM -0700, John Baldwin wrote: > On Monday, August 29, 2016 09:58:13 AM Konstantin Belousov wrote: > > I dug into the ptrace(2) consumers, I found a lot of things using > > it which I would not expect to use, besides usual suspects of gdb > > lldb libunwind reptyr etc. Most surprising was that even high-profile > > consumers including gdb sometimes fail to check errno after PT_PEEK. On > > the other hand, I did not found a case in gdb where errno is checked > > after PT_PEEK but not zeroed before the syscall. > > So the consumers are generally doing the right thing. I only looked at gdb in details, other code is painful to read. > Certainly I think having a C wrapper like this makes more sense than > doing it all in assembly N times. I would probably prefer to keep the > manpage language the way it is though. So do you want to revert man page bits ? > > If we are really worried about compat, we could bump the ptrace symver > and use the function above as the FBSD_1.0 version perhaps. This does not solve anything. Old-time compiled consumers would get the expected interface, while the same consumers compiled anew get incompatible interface. Recent dirname/basename change demostrates the same problem. On Mon, Aug 29, 2016 at 08:46:47PM +0300, Andrey Chernov wrote: > Either we implement this wrapper or left all things as is, we need to > document internal errno clearing additionally, to not make people wonder > why errno becomes 0, probably with the mention that program should not > relay on this obsoleted implementation feature. It was done in r304928. John want to revert this change, it seems.
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