diff options
| author | Jean Boussier <[email protected]> | 2024-05-29 16:46:04 +0200 |
|---|---|---|
| committer | Jean Boussier <[email protected]> | 2024-09-05 11:43:46 +0200 |
| commit | 63cbe3f6ac9feb44a2e43b1f853e2ca7e049316c () | |
| tree | dddbbbc8678332d16f9cf5e9630645e233656797 /ext/socket/raddrinfo.c | |
| parent | 2e5680d304a9cf9a6a2ba582091af6719e839351 (diff) | |
Proof of Concept: Allow to prevent fork from happening in known fork unsafe API
[Feature #20590] For better of for worse, fork(2) remain the primary provider of parallelism in Ruby programs. Even though it's frowned uppon in many circles, and a lot of literature will simply state that only async-signal safe APIs are safe to use after `fork()`, in practice most APIs work well as long as you are careful about not forking while another thread is holding a pthread mutex. One of the APIs that is known cause fork safety issues is `getaddrinfo`. If you fork while another thread is inside `getaddrinfo`, a mutex may be left locked in the child, with no way to unlock it. I think we could reduce the impact of these problem by preventing in for the most notorious and common cases, by locking around `fork(2)` and known unsafe APIs with a read-write lock.
Notes: Merged: https://.com/ruby/ruby/pull/10864
| -rw-r--r-- | ext/socket/raddrinfo.c | 16 |
1 files changed, 14 insertions, 2 deletions
@@ -327,6 +327,12 @@ nogvl_getaddrinfo(void *arg) return (void *)(VALUE)ret; } static int rb_getaddrinfo(const char *hostp, const char *portp, const struct addrinfo *hints, struct addrinfo **ai) { @@ -336,7 +342,7 @@ rb_getaddrinfo(const char *hostp, const char *portp, const struct addrinfo *hint arg.service = portp; arg.hints = hints; arg.res = ai; - return (int)(VALUE)rb_thread_call_without_gvl(nogvl_getaddrinfo, &arg, RUBY_UBF_IO, 0); } #elif GETADDRINFO_IMPL == 2 @@ -477,6 +483,12 @@ do_pthread_create(pthread_t *th, void *(*start_routine) (void *), void *arg) return ret; } static int rb_getaddrinfo(const char *hostp, const char *portp, const struct addrinfo *hints, struct addrinfo **ai) { @@ -493,7 +505,7 @@ start: } pthread_t th; - if (do_pthread_create(&th, do_getaddrinfo, arg) != 0) { int err = errno; free_getaddrinfo_arg(arg); errno = err; |