827825 - IPDL single-process Shmem not working on windows

Status: RESOLVED FIXED

(Core :: IPC, defect)

Description

[Bas Schouten (:bas.schouten)]

Allocating shmem on windows in a multi-thread single-process IPDL setup is not working. It's failing because mOtherProcess is NULL on the parent. This can trivially be reproduced by running ipdlunittest thread:TestShmem.

Comment 1

[Bas Schouten (:bas.schouten)]

Attachment: Make mOtherProcess the current process for single-process IPDL protocols

When calling ShareTo for a shmem we use OtherProcess() to indicate which process to share memory to. For Windows this actually matters since the security model requires explicitly specifying which process gets access to your memory (the parameter is ignored for posix). The Chromium ShareTo code has a special case for otherProcess == thisProcess(), but not for !otherProcess. The best solution here is probably to make mOtherProcess have a sane value (although this could make the name -slightly- confusing for single-process cases.)

Comment 2

[Chris Jones [:cjones] inactive; ni?/f?/r? if you need me]

Comment on attachment 699266 [details] [diff] [review]
Make mOtherProcess the current process for single-process IPDL protocols

I don't see any code that's relying on null mOtherProcess to mean "is cross-thread", and if it exists and doesn't have a test then ah well.

Comment 3

[Bas Schouten (:bas.schouten)]

https://hg.mozilla.org/integration/mozilla-inbound/rev/7dc925609a39

Comment 4

[Ed Morley [:emorley]]

https://hg.mozilla.org/mozilla-central/rev/7dc925609a39