Ensure to close pipes when TCPSocket.new finishes processing (ruby#12181)

`TCPSocket.new` with HEv2 uses three threads.
The last of these threads to exit closed pipes.
However, if pipes were open at the end of the main thread, they would leak.
This change avoids this by closing pipes at the end of the main thread.

Author: shioimm

ext/socket/ipsocket.c

@@ -229,6 +229,7 @@ struct fast_fallback_inetsock_arg
     rb_nativethread_lock_t *lock;
     struct fast_fallback_getaddrinfo_entry *getaddrinfo_entries[2];
     struct fast_fallback_getaddrinfo_shared *getaddrinfo_shared;
+    int wait;
     int connection_attempt_fds_size;
     int *connection_attempt_fds;
     VALUE test_mode_settings;
@@ -313,7 +314,7 @@ cancel_fast_fallback(void *ptr)
     {
         arg->cancelled = true;
         char notification = SELECT_CANCELLED;
-        if ((write(arg->notify, &notification, 1)) < 0) {
+        if (arg->notify != -1 && (write(arg->notify, &notification, 1)) < 0) {
             rb_syserr_fail(errno, "write(2)");
         }
     }
@@ -554,7 +555,7 @@ init_fast_fallback_inetsock_internal(VALUE v)
     pthread_t threads[arg->family_size];
     char resolved_type[2];
     ssize_t resolved_type_size;
-    int hostname_resolution_waiter = 0, hostname_resolution_notifier = 0;
+    int hostname_resolution_waiter = -1, hostname_resolution_notifier = -1;
     int pipefd[2];
     fd_set readfds, writefds;
 
@@ -587,6 +588,7 @@ init_fast_fallback_inetsock_internal(VALUE v)
     if ((fcntl(hostname_resolution_waiter, F_SETFL, waiter_flags | O_NONBLOCK)) < 0) {
         rb_syserr_fail(errno, "fcntl(2)");
     }
+    arg->wait = hostname_resolution_waiter;
 
     hostname_resolution_notifier = pipefd[1];
     wait_arg.readfds = &readfds;
@@ -599,7 +601,6 @@ init_fast_fallback_inetsock_internal(VALUE v)
     rb_nativethread_lock_initialize(arg->getaddrinfo_shared->lock);
 
     arg->getaddrinfo_shared->notify = hostname_resolution_notifier;
-    arg->getaddrinfo_shared->wait = hostname_resolution_waiter;
     arg->getaddrinfo_shared->connection_attempt_fds = arg->connection_attempt_fds;
     arg->getaddrinfo_shared->connection_attempt_fds_size = arg->connection_attempt_fds_size;
     arg->getaddrinfo_shared->cancelled = false;
@@ -1191,6 +1192,10 @@ fast_fallback_inetsock_cleanup(VALUE v)
         arg->local.res = 0;
     }
 
+    if (arg->wait != -1) close(arg->wait);
+    if (getaddrinfo_shared->notify != -1) close(getaddrinfo_shared->notify);
+    getaddrinfo_shared->notify = -1;
+
     if (getaddrinfo_shared) {
         if (arg->family_size == 1) {
             free_fast_fallback_getaddrinfo_shared(&getaddrinfo_shared);

ext/socket/raddrinfo.c

@@ -3033,8 +3033,6 @@ free_fast_fallback_getaddrinfo_shared(struct fast_fallback_getaddrinfo_shared **
     (*shared)->node = NULL;
     free((*shared)->service);
     (*shared)->service = NULL;
-    close((*shared)->notify);
-    close((*shared)->wait);
     rb_nativethread_lock_destroy((*shared)->lock);
     free(*shared);
     *shared = NULL;
@@ -3057,6 +3055,11 @@ do_fast_fallback_getaddrinfo(void *ptr)
     struct fast_fallback_getaddrinfo_shared *shared = entry->shared;
     int err = 0, need_free = 0, shared_need_free = 0;
 
+    sigset_t set;
+    sigemptyset(&set);
+    sigaddset(&set, SIGPIPE);
+    pthread_sigmask(SIG_BLOCK, &set, NULL);
+
     err = numeric_getaddrinfo(shared->node, shared->service, &entry->hints, &entry->ai);
 
     if (err != 0) {
@@ -3101,7 +3104,7 @@ do_fast_fallback_getaddrinfo(void *ptr)
             const char notification = entry->family == AF_INET6 ?
             IPV6_HOSTNAME_RESOLVED : IPV4_HOSTNAME_RESOLVED;
 
-            if ((write(shared->notify, &notification, 1)) < 0) {
+            if (shared->notify != -1 && (write(shared->notify, &notification, 1)) < 0) {
                 entry->err = errno;
                 entry->has_syserr = true;
             }

ext/socket/rubysocket.h

@@ -440,7 +440,7 @@ struct fast_fallback_getaddrinfo_entry
 
 struct fast_fallback_getaddrinfo_shared
 {
-    int wait, notify, refcount, connection_attempt_fds_size;
+    int notify, refcount, connection_attempt_fds_size;
     int cancelled;
     int *connection_attempt_fds;
     char *node, *service;