CLIENT: fix thread unsafe acces to get*ent structs. #6333
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All get*ent structs were protected with socket mutex. In case SSSD is built with lock-free client support, `sss_nss_lock()` is a no-op, thus resulting in thread unsafe access. This patch changes those structs to have thread local storage. This conradicts following note in the man page: ``` The function getgrent_r() is not really reentrant since it shares the reading position in the stream with all other threads. ``` I'm not sure if 3rd party apps can legally assume this behaviour based on a note in a man page. And in some cases, non-sharing reading position between threads might make more sense. But that way or another, this is better than thread unsafe access.
alexey-tikhonov
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sumit-bose,
justin-stephenson and
pbrezina
alexey-tikhonov
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backport-to-stable
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Hi, to make those structures thread-local seems like a proper way to me to protect them against parallel access. I think we can ignore the case where e.g. bye, |
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I agree. Ack. |
pbrezina
approved these changes
Sep 2, 2022
sumit-bose
approved these changes
Sep 15, 2022
pbrezina
added
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All get*ent structs were protected with socket mutex. In case SSSD
is built with lock-free client support,
sss_nss_lock()is a no-op,thus resulting in thread unsafe access.
This patch changes those structs to have thread local storage.
This conradicts following note in the man page:
I'm not sure if 3rd party apps can legally assume this behaviour
based on a note in a man page. And in some cases, non-sharing reading
position between threads might make more sense.
But that way or another, this is better than thread unsafe access.