kdump: decode pollfd struct arrays coming from poll(2)
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Authored by kevans on Feb 29 2024, 4:47 PM.

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jhb
bapt
dchagin

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rG02c57f7b4877: kdump: decode pollfd struct arrays coming from poll(2)

Summary

We'll handle these just as we do kevents, one per line with subsequent
lines indented sufficiently to distinguish them from the upcoming
return value.

Sample, with indentation stripped and revents changed to '...' in the
first one to keep the line length down:

CALL poll(0x820610560,0x3,0)
STRU struct pollfd[] = { { fd=0, events=0x1<POLLIN>, revents=0x11<...>
{ fd=1, events=0x4<POLLOUT>, revents=0x4<POLLOUT>}
{ fd=-1, events=0x4<POLLOUT>, revents=0} }
RET poll 2

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rG FreeBSD src repository

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kevans created this revision.Feb 29 2024, 4:47 PM

Herald added a subscriber: imp. · View Herald TranscriptFeb 29 2024, 4:47 PM

kevans requested review of this revision.Feb 29 2024, 4:47 PM

Harbormaster completed remote builds in B56353: Diff 135235.Feb 29 2024, 4:47 PM

kevans added a parent revision: D44159: libsysdecode: add a decoder for pollfd events.Feb 29 2024, 4:47 PM

I love it, thank you!

This revision is now accepted and ready to land.Feb 29 2024, 4:51 PM

Next you might consider adding this to truss as well. :)

In D44160#1008533, @jhb wrote:

Next you might consider adding this to truss as well. :)

I'm actually not sure what this would look like for truss... it does some decoding of events already, just not returned events:

820 100189: poll({ 0/POLLIN 1/POLLOUT -1/POLLOUT 1/POLLHUP },4,0) = 1 (0x1)

It's a little more obvious with kqueue since the results are returned in a separate parameter, so that gives a natural representation... the best I can come up with off the top of my head is maybe something like:

820 100189: poll({ 0/{POLLIN -> 0} 1/{POLLOUT -> POLLOUT} -1/{POLLOUT -> 0} 1/{POLLHUP -> 0} },4,0) = 1 (0x1)

but I'm afraid that might get a little convoluted

Oh, that probably won't work... we probably printed the entire left-hand side before the return, so it'd need to be on a separate line or something

Closed by commit rG02c57f7b4877: kdump: decode pollfd struct arrays coming from poll(2) (authored by kevans). · Explain WhyMar 5 2024, 5:46 AM

This revision was automatically updated to reflect the committed changes.

kevans added a commit: rG02c57f7b4877: kdump: decode pollfd struct arrays coming from poll(2).

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usr.bin/

kdump/

kdump.c

20 lines

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kdump: decode pollfd struct arrays coming from poll(2)ClosedPublicActions