Date: Mon, 21 Oct 1996 11:34:15 +0930 (CST) From: Michael Smith <msmith@atrad.adelaide.edu.au> To: dtc@scrooge.ee.swin.oz.au (Douglas Thomas Crosher) Cc: msmith@atrad.adelaide.edu.au, freebsd-current@freebsd.org Subject: Re: kern/1848: breakpoints in shared libraries don't fire Message-ID: <199610210204.LAA04119@genesis.atrad.adelaide.edu.au> In-Reply-To: <199610201502.BAA17461@scrooge.ee.swin.oz.au> from "Douglas Thomas Crosher" at Oct 21, 96 01:02:22 am
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Douglas Thomas Crosher stands accused of saying: > > > > > It's possible to set breakpoints in shared libraries, but > > > > executing the code doesn't cause a SIGTRACE. > > > > Setting a breakpoint in a shared library would be Bad, as you don't > > have any way of telling who else it is shared with. I suspect that > > the attempt to set the trace is silently failing. > > What about pages mmapped MAP_PRIVATE, couldn't the page be copied for > private use when the breakpoint is set? I'm sure it _could_, after all it's just software. However ld.so most likely maps pages as readonly, so you would have to make some changes there (to detect whether a program was being debugged etc.), or teach gdb to change the mappings on shared libraries. > Douglas Crosher -- ]] Mike Smith, Software Engineer msmith@atrad.adelaide.edu.au [[ ]] Genesis Software genesis@atrad.adelaide.edu.au [[ ]] High-speed data acquisition and (GSM mobile) <STOLEN> [[ ]] realtime instrument control (ph/fax) +61-8-8267-3493 [[ ]] Collector of old Unix hardware. "Where are your PEZ?" The Tick [[
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