> On 2 Jul 2025, at 13:44, Peter Eisentraut <pe...@eisentraut.org> wrote: > > On 27.06.25 19:24, Daniel Gustafsson wrote: >> The OpenSSL code in libpq have two issues for multithreading: the verify_cb >> callback use a global variable to pass back error detail state and there is >> one >> use of strerror(). > > Slightly misleading title: This is actually about the *backend* libpq code.
Point taken, proposed commitmessage has been updated. >> The attached fixes both, with no functional change, in order to pave the way >> for multithreading: >> * Rather than using a global variable the callback use a new member in the >> Port struct for passing the string, and the Port struct is in turn passed >> as >> private data in the SSL object > > Couldn't this also be done by making that global variable thread-local? But > getting rid of it is even nicer. It absolutely could, and I briefly considered this approach, but I prefer getting rid of it altogether. >> * The strerror call is replaced with a strerror_r call using the already >> existing errorbuffer > > This one was already discussed some time ago at > <https://www.postgresql.org/message-id/flat/daa87d79-c044-46c4-8458-8d77241ed7b0%40eisentraut.org>: > > > But the bigger issue is that the use of a static buffer makes > > this not thread-safe, so having it use strerror_r to fill that > > buffer is just putting lipstick on a pig. > > It looks like your patch doesn't address that? Doh, of course. The attached v2 takes a stab at moving from using a static buffer to a palloced buffer with the caller being responsible for freeing. In paths which lead to proc_exit we can omit freeing. -- Daniel Gustafsson
v2-0001-libpq-Make-SSL-errorhandling-in-backend-threadsaf.patch
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