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fdpass_recv: Set O_CLOEXEC on received fds

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Turns out this is necessary even if the fd is going to be passed through
exec() soon, because the supervisor might receive multiple fds before
spawning another process, in which case all of them are going to be
passed to the new process instead of just one.
This commit is contained in:
Yorhel 2025-03-24 11:07:36 +01:00
parent 9e1be5bc71
commit 2f50736782
3 changed files with 9 additions and 13 deletions
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7
FU/Util.pm
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@ -458,10 +458,9 @@ Like regular socket I/O, a single C<fdpass_send()> message may be split across
multiple C<fdpass_recv()> calls; in that case the C<$fd> is only received on
the first call.
Don't use this function if the sender may include multiple file descriptors in
a single message, weird things can happen. File descriptors received this way
do not have the C<CLOEXEC> flag and will thus survive a call to C<exec()>.
Refer to L<this wonderful
The C<O_CLOEXEC> flag is set on received file descriptors. Don't use this
function if the sender may include multiple file descriptors in a single
message, weird things can happen. Refer to L<this wonderful
discussion|https://gist.github.com/kentonv/bc7592af98c68ba2738f4436920868dc>
for more weirdness and edge cases.