supabase / pg_net / 38348109883

94%

push

github

fix: undefined behaviour in worker

The `epfd` and `curl_mhandle` variables were stored in shared memory and if the
background worker process terminated before these were initialized, the cleanup
in `net_on_exit` function ran on stale values from the last exited background
worker which caused undefined behaviour by trying to cleanup that stale value.
It also closed a stale fd which could close an unrelated fd.

The fix is to move the state outside the shared memory. `epfd` is made a static
variable in event.c and `curl_mhandle` a static variable in worker.c. After
these changes, the rest is adjusting the code to make it compile. Other smaller
fixes are related to the initialization and cleanup of `epfd`, `timerfd`,
`curl_mhandle`, and curl library itself. We now make sure we cleanup the
appropriate resources only when they were successfully initialized.

Fixes #276. Note that the old code exhibited undefined behaviour which could
manifest as a segfault, but that depends on many factors like address layout and
is not guaranteed.

40 of 46 new or added lines in 3 files covered. (86.96%)

568 of 604 relevant lines covered (94.04%)

484.69 hits per line