I tried to revert the rpmdb/legacy.c back to 5.3, 5.2. and 5.1 versions. They all have the same issue.
I attempted the same within the prelink side of things, and as far as I can tell the code for writing to stdout for RPM validation hasn't changed in about 5 years. So I'm at a bit of a loss to explain whats wrong, and why it suddenly happened. :( --Mark On 2/25/11 6:07 PM, Mark Hatle wrote: > On 2/25/11 5:53 PM, Jeff Johnson wrote: >> >> On Feb 25, 2011, at 6:27 PM, Mark Hatle wrote: >> >>> On 2/25/11 8:40 AM, Mark Hatle wrote: >>>> On 2/24/11 10:41 PM, Jeff Johnson wrote: >>>>> >>>>> On Feb 24, 2011, at 11:14 PM, Mark Hatle wrote: >>>>> >>>>>> I'm trying to validate prelinked binaries and I'm getting a somewhat >>>>>> strange result: >>>>>> >>>>>> ........ /bin >>>>>> S.?..... /bin/bash >>>>>> ........ /bin/bashbug >>> >>> Ok, I've done more digging. If I run this within gdb, I'm suddenly seeing >>> an >>> error message appear on the screen: >>> >>> prelink: Couldn't write file to standard output: Broken pipe >>> S.?..... <filename> >>> >>> However, if I use gdb and step through the fork/exec in rpmdb/legacy.c at >>> around >>> like 128.. I don't get the error message -- and it comes back with a "." >>> for a >>> valid md5um. (If I run this without GDB, I get the '?' and no error message >>> from prelink.) >>> >>> So it looks like we have some type of pipe issue. >>> >>> Any suggestions? >>> >> >> Hmmm ... that sounds like racy or signal delivery to me ... parent >> is AWOL when prelink is trying to write to the stdout pipe fdno >> leading to EPIPE. >> >> (aisde, basis for guessing "racy") >> getOutputFrom() has always been racy. mostly fixed @rpm.org too, >> I'll swipe the code one of these days. >> >> But the select/poll delay is sufficient to get the child plugged >> onto the pipe @rpm5.org. been "gud enuf" for years in rpmbuild but the >> code is pathetic. >> >> (back to running prelink undo onto a pipe) >> >> OK, legacy.c is classic fork/exec. Kinda hard to break something >> there, but won't be the first time I've screwed a fork/exec somehow. > > Ya, I looked at this and don't see an obvious race... > >> About all that's new/different in legacy.c is the yarnLock()'s I added to try >> to protect the static lazily allocated cmd strings while getting up >> to speed on DRD/Helgrind tools in valgrind. > > I doubt that is the issue as well.. > >> My test case was >> rpm --Va >> so prelink undo (and the legacy.c code changes) was exercised >> pretty thoroughly. >> >> You might want to diff legacy.c against 5.2.1 or 5.1.9 just to see if >> I screwed up in 5.4.0 somehow. There really hasn'nt been any changes >> to legacy.c for a L-O-N-G time, all the code is destined for the >> bit bucket somewhen (and prelink undo will eventually become a >> dlopen() module toed into a --verify framework). But there's >> zero interest in changing anything in RPM so I haven't bothered. > > I'll run a diff and see what I get, but this doesn't look any different (then > the yarn locks) since the last time I looked at this code a few years ago. > >> Perhaps a stricter interlocked parent <-> child startup is needed >> (though I don't see why reading code). But linux is known to >> run child before parent which might get tricky. Anyways opening >> _ANOTHER_ pipe and having the child block on a read() until >> the parent starts running and closes the other end of the pipe >> (wherein child returns from read with 0b aka an EOF) could be attempted. >> >> Still -- the only state in the fork/exec is in pipes[2] and the fdno return. >> >> I sure don't see what else is needed. > > Ya, it doesn't LOOK like there should be a problem.. but I'll run some diffs > and > see. > > --Mark > >> Does prelink outside of rpm Just Work or not? If standalone >> prelink Just Works then I broke rpm-5.4.0 in some fashion that >> I cannot see. Try going back to legacy.c from rpm-5.2.1 is about >> all I can think of to get _SOMETHING_ working and then staring at the diff >> and/or bisecting back until its obvious what is wrong is all I can think of. >> >> hth >> >> 73 de Jeff > > ______________________________________________________________________ > RPM Package Manager http://rpm5.org > Developer Communication List rpm-devel@rpm5.org ______________________________________________________________________ RPM Package Manager http://rpm5.org Developer Communication List rpm-devel@rpm5.org
