OXIESEC PANEL

Name	Size	Modified	Perms
📁 ..	-	02/02/2024 06:09:55 PM	rwxr-xr-x
📄 addrselect.go	9.69 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 addrselect_test.go	8.5 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 cgo_aix.go	582 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 cgo_android.go	272 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 cgo_bsd.go	343 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 cgo_darwin.go	298 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 cgo_linux.go	642 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 cgo_netbsd.go	276 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 cgo_openbsd.go	276 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 cgo_resnew.go	580 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 cgo_resold.go	579 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 cgo_socknew.go	753 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 cgo_sockold.go	842 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 cgo_solaris.go	343 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 cgo_stub.go	1.33 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 cgo_unix.go	11.35 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 cgo_unix_cgo.go	2.24 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 cgo_unix_cgo_darwin.go	461 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 cgo_unix_cgo_res.go	911 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 cgo_unix_cgo_resn.go	998 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 cgo_unix_syscall.go	2.99 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 cgo_unix_test.go	1.44 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 conf.go	15.63 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 conf_test.go	12.28 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 conn_test.go	1.82 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 dial.go	25.68 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 dial_test.go	30.14 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 dial_unix_test.go	2.77 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 dnsclient.go	5.65 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 dnsclient_test.go	1.51 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 dnsclient_unix.go	24.26 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 dnsclient_unix_test.go	69.13 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 dnsconfig.go	1.73 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 dnsconfig_unix.go	4.16 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 dnsconfig_unix_test.go	7.07 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 dnsconfig_windows.go	1.6 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 dnsname_test.go	1.96 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 error_plan9.go	224 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 error_plan9_test.go	437 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 error_posix.go	543 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 error_posix_test.go	981 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 error_test.go	20.32 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 error_unix.go	382 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 error_unix_test.go	723 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 error_windows.go	355 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 error_windows_test.go	757 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 example_test.go	8.45 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 external_test.go	4.05 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 fd_fake.go	3.79 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 fd_js.go	627 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 fd_plan9.go	3.56 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 fd_posix.go	4.29 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 fd_unix.go	5.43 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 fd_wasip1.go	496 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 fd_windows.go	6.14 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 file.go	1.69 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 file_plan9.go	2.72 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 file_stub.go	481 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 file_test.go	6.43 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 file_unix.go	2.5 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 file_unix_test.go	2.07 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 file_wasip1.go	2.2 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 file_wasip1_test.go	3.76 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 file_windows.go	521 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 hook.go	894 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 hook_plan9.go	211 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 hook_unix.go	658 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 hook_windows.go	720 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 hosts.go	3.48 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 hosts_test.go	5.6 KB	02/02/2024 06:09:55 PM	rw-r--r--
📁 http	-	02/02/2024 06:09:55 PM	rwxr-xr-x
📄 interface.go	7.26 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 interface_aix.go	4.46 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 interface_bsd.go	2.82 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 interface_bsd_test.go	1.44 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 interface_bsdvar.go	718 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 interface_darwin.go	1.29 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 interface_freebsd.go	1.29 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 interface_linux.go	6.96 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 interface_linux_test.go	3.65 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 interface_plan9.go	4.71 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 interface_solaris.go	2.13 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 interface_stub.go	814 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 interface_test.go	9.76 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 interface_unix_test.go	4.85 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 interface_windows.go	5.43 KB	02/02/2024 06:09:55 PM	rw-r--r--
📁 internal	-	02/02/2024 06:09:55 PM	rwxr-xr-x
📄 ip.go	13.88 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 ip_test.go	25.6 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 iprawsock.go	7.11 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 iprawsock_plan9.go	874 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 iprawsock_posix.go	3.89 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 iprawsock_test.go	5.98 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 ipsock.go	9.05 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 ipsock_plan9.go	7.48 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 ipsock_plan9_test.go	645 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 ipsock_posix.go	7.86 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 ipsock_test.go	6.81 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 listen_test.go	20.5 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 lookup.go	29.04 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 lookup_plan9.go	9.94 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 lookup_test.go	40.62 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 lookup_unix.go	3.35 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 lookup_windows.go	13.8 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 lookup_windows_test.go	8.93 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 mac.go	1.88 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 mac_test.go	3.26 KB	02/02/2024 06:09:55 PM	rw-r--r--
📁 mail	-	02/02/2024 06:09:55 PM	rwxr-xr-x
📄 main_cloexec_test.go	693 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 main_conf_test.go	1.39 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 main_noconf_test.go	467 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 main_plan9_test.go	392 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 main_posix_test.go	1.37 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 main_test.go	7.53 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 main_unix_test.go	1.19 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 main_wasm_test.go	284 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 main_windows_test.go	1 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 mockserver_test.go	10.77 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 mptcpsock_linux.go	3.96 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 mptcpsock_linux_test.go	4.06 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 mptcpsock_stub.go	542 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 net.go	24.56 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 net_fake.go	26.36 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 net_fake_test.go	2.79 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 net_test.go	14 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 net_windows_test.go	16.28 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 netcgo_off.go	222 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 netcgo_on.go	220 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 netgo_netcgo.go	453 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 netgo_off.go	220 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 netgo_on.go	218 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📁 netip	-	02/02/2024 06:09:55 PM	rwxr-xr-x
📄 nss.go	5.48 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 nss_test.go	3.4 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 packetconn_test.go	3.02 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 parse.go	6.04 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 parse_test.go	1.55 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 pipe.go	5.43 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 pipe_test.go	1.2 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 platform_test.go	4.33 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 port.go	1.46 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 port_test.go	1.34 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 port_unix.go	1.24 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 protoconn_test.go	7.44 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 rawconn.go	2.7 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 rawconn_stub_test.go	631 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 rawconn_test.go	4.33 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 rawconn_unix_test.go	2.96 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 rawconn_windows_test.go	3.12 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 resolverdialfunc_test.go	8.25 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 rlimit_js.go	346 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 rlimit_unix.go	1.1 KB	02/02/2024 06:09:55 PM	rw-r--r--
📁 rpc	-	02/02/2024 06:09:55 PM	rwxr-xr-x
📄 sendfile_linux.go	1.12 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 sendfile_linux_test.go	1.93 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 sendfile_stub.go	344 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 sendfile_test.go	8.25 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 sendfile_unix_alt.go	2.04 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 sendfile_windows.go	1.02 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 server_test.go	11.67 KB	02/02/2024 06:09:55 PM	rw-r--r--
📁 smtp	-	02/02/2024 06:09:55 PM	rwxr-xr-x
📄 sock_bsd.go	918 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 sock_cloexec.go	1.38 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 sock_linux.go	993 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 sock_linux_test.go	575 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 sock_plan9.go	262 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 sock_posix.go	6.29 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 sock_stub.go	390 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 sock_windows.go	802 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 sockaddr_posix.go	1.45 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 sockopt_aix.go	1.43 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 sockopt_bsd.go	2.21 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 sockopt_fake.go	955 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 sockopt_linux.go	1.25 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 sockopt_plan9.go	406 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 sockopt_posix.go	2.13 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 sockopt_solaris.go	1.25 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 sockopt_windows.go	1.51 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 sockoptip_bsdvar.go	867 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 sockoptip_linux.go	735 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 sockoptip_posix.go	1.38 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 sockoptip_stub.go	769 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 sockoptip_windows.go	786 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 splice_linux.go	1.69 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 splice_stub.go	376 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 splice_test.go	13.48 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 sys_cloexec.go	962 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 tcpsock.go	11.75 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 tcpsock_plan9.go	2.18 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 tcpsock_posix.go	6.16 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 tcpsock_test.go	17.68 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 tcpsock_unix_test.go	2.34 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 tcpsockopt_darwin.go	770 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 tcpsockopt_dragonfly.go	698 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 tcpsockopt_openbsd.go	365 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 tcpsockopt_plan9.go	525 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 tcpsockopt_posix.go	442 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 tcpsockopt_solaris.go	1.15 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 tcpsockopt_stub.go	399 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 tcpsockopt_unix.go	722 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 tcpsockopt_windows.go	741 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📁 testdata	-	02/02/2024 06:09:55 PM	rwxr-xr-x
📁 textproto	-	02/02/2024 06:09:55 PM	rwxr-xr-x
📄 timeout_test.go	29.11 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 udpsock.go	11.83 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 udpsock_plan9.go	4.64 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 udpsock_plan9_test.go	1.31 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 udpsock_posix.go	7.53 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 udpsock_test.go	17.24 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 unixsock.go	10.12 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 unixsock_linux_test.go	2.29 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 unixsock_plan9.go	1.24 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 unixsock_posix.go	6.64 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 unixsock_readmsg_cloexec.go	654 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 unixsock_readmsg_cmsg_cloexec.go	332 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 unixsock_readmsg_other.go	275 bytes	02/02/2024 06:09:55 PM	rw-r--r--
📄 unixsock_readmsg_test.go	2.51 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 unixsock_test.go	10.64 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 unixsock_windows_test.go	2.03 KB	02/02/2024 06:09:55 PM	rw-r--r--
📁 url	-	02/02/2024 06:09:55 PM	rwxr-xr-x
📄 write_unix_test.go	1.61 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 writev_test.go	5.03 KB	02/02/2024 06:09:55 PM	rw-r--r--
📄 writev_unix.go	666 bytes	02/02/2024 06:09:55 PM	rw-r--r--

Editing: cgo_unix.go

// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

// This file is called cgo_unix.go, but to allow syscalls-to-libc-based
// implementations to share the code, it does not use cgo directly.
// Instead of C.foo it uses _C_foo, which is defined in either
// cgo_unix_cgo.go or cgo_unix_syscall.go

//go:build !netgo && ((cgo && unix) || darwin)

package net

import (
	"context"
	"errors"
	"net/netip"
	"syscall"
	"unsafe"

"golang.org/x/net/dns/dnsmessage"
)

// cgoAvailable set to true to indicate that the cgo resolver
// is available on this system.
const cgoAvailable = true

// An addrinfoErrno represents a getaddrinfo, getnameinfo-specific
// error number. It's a signed number and a zero value is a non-error
// by convention.
type addrinfoErrno int

func (eai addrinfoErrno) Error() string   { return _C_gai_strerror(_C_int(eai)) }
func (eai addrinfoErrno) Temporary() bool { return eai == _C_EAI_AGAIN }
func (eai addrinfoErrno) Timeout() bool   { return false }

// isAddrinfoErrno is just for testing purposes.
func (eai addrinfoErrno) isAddrinfoErrno() {}

// doBlockingWithCtx executes a blocking function in a separate goroutine when the provided
// context is cancellable. It is intended for use with calls that don't support context
// cancellation (cgo, syscalls). blocking func may still be running after this function finishes.
func doBlockingWithCtx[T any](ctx context.Context, blocking func() (T, error)) (T, error) {
	if ctx.Done() == nil {
		return blocking()
	}

type result struct {
		res T
		err error
	}

res := make(chan result, 1)
	go func() {
		var r result
		r.res, r.err = blocking()
		res <- r
	}()

select {
	case r := <-res:
		return r.res, r.err
	case <-ctx.Done():
		var zero T
		return zero, mapErr(ctx.Err())
	}
}

func cgoLookupHost(ctx context.Context, name string) (hosts []string, err error) {
	addrs, err := cgoLookupIP(ctx, "ip", name)
	if err != nil {
		return nil, err
	}
	for _, addr := range addrs {
		hosts = append(hosts, addr.String())
	}
	return hosts, nil
}

func cgoLookupPort(ctx context.Context, network, service string) (port int, err error) {
	var hints _C_struct_addrinfo
	switch network {
	case "ip": // no hints
	case "tcp", "tcp4", "tcp6":
		*_C_ai_socktype(&hints) = _C_SOCK_STREAM
		*_C_ai_protocol(&hints) = _C_IPPROTO_TCP
	case "udp", "udp4", "udp6":
		*_C_ai_socktype(&hints) = _C_SOCK_DGRAM
		*_C_ai_protocol(&hints) = _C_IPPROTO_UDP
	default:
		return 0, &DNSError{Err: "unknown network", Name: network + "/" + service}
	}
	switch ipVersion(network) {
	case '4':
		*_C_ai_family(&hints) = _C_AF_INET
	case '6':
		*_C_ai_family(&hints) = _C_AF_INET6
	}

return doBlockingWithCtx(ctx, func() (int, error) {
		return cgoLookupServicePort(&hints, network, service)
	})
}

func cgoLookupServicePort(hints *_C_struct_addrinfo, network, service string) (port int, err error) {
	cservice, err := syscall.ByteSliceFromString(service)
	if err != nil {
		return 0, &DNSError{Err: err.Error(), Name: network + "/" + service}
	}
	// Lowercase the C service name.
	for i, b := range cservice[:len(service)] {
		cservice[i] = lowerASCII(b)
	}
	var res *_C_struct_addrinfo
	gerrno, err := _C_getaddrinfo(nil, (*_C_char)(unsafe.Pointer(&cservice[0])), hints, &res)
	if gerrno != 0 {
		isTemporary := false
		switch gerrno {
		case _C_EAI_SYSTEM:
			if err == nil { // see golang.org/issue/6232
				err = syscall.EMFILE
			}
		case _C_EAI_SERVICE, _C_EAI_NONAME: // Darwin returns EAI_NONAME.
			return 0, &DNSError{Err: "unknown port", Name: network + "/" + service, IsNotFound: true}
		default:
			err = addrinfoErrno(gerrno)
			isTemporary = addrinfoErrno(gerrno).Temporary()
		}
		return 0, &DNSError{Err: err.Error(), Name: network + "/" + service, IsTemporary: isTemporary}
	}
	defer _C_freeaddrinfo(res)

for r := res; r != nil; r = *_C_ai_next(r) {
		switch *_C_ai_family(r) {
		case _C_AF_INET:
			sa := (*syscall.RawSockaddrInet4)(unsafe.Pointer(*_C_ai_addr(r)))
			p := (*[2]byte)(unsafe.Pointer(&sa.Port))
			return int(p[0])<<8 | int(p[1]), nil
		case _C_AF_INET6:
			sa := (*syscall.RawSockaddrInet6)(unsafe.Pointer(*_C_ai_addr(r)))
			p := (*[2]byte)(unsafe.Pointer(&sa.Port))
			return int(p[0])<<8 | int(p[1]), nil
		}
	}
	return 0, &DNSError{Err: "unknown port", Name: network + "/" + service, IsNotFound: true}
}

func cgoLookupHostIP(network, name string) (addrs []IPAddr, err error) {
	acquireThread()
	defer releaseThread()

var hints _C_struct_addrinfo
	*_C_ai_flags(&hints) = cgoAddrInfoFlags
	*_C_ai_socktype(&hints) = _C_SOCK_STREAM
	*_C_ai_family(&hints) = _C_AF_UNSPEC
	switch ipVersion(network) {
	case '4':
		*_C_ai_family(&hints) = _C_AF_INET
	case '6':
		*_C_ai_family(&hints) = _C_AF_INET6
	}

h, err := syscall.BytePtrFromString(name)
	if err != nil {
		return nil, &DNSError{Err: err.Error(), Name: name}
	}
	var res *_C_struct_addrinfo
	gerrno, err := _C_getaddrinfo((*_C_char)(unsafe.Pointer(h)), nil, &hints, &res)
	if gerrno != 0 {
		isErrorNoSuchHost := false
		isTemporary := false
		switch gerrno {
		case _C_EAI_SYSTEM:
			if err == nil {
				// err should not be nil, but sometimes getaddrinfo returns
				// gerrno == _C_EAI_SYSTEM with err == nil on Linux.
				// The report claims that it happens when we have too many
				// open files, so use syscall.EMFILE (too many open files in system).
				// Most system calls would return ENFILE (too many open files),
				// so at the least EMFILE should be easy to recognize if this
				// comes up again. golang.org/issue/6232.
				err = syscall.EMFILE
			}
		case _C_EAI_NONAME, _C_EAI_NODATA:
			err = errNoSuchHost
			isErrorNoSuchHost = true
		default:
			err = addrinfoErrno(gerrno)
			isTemporary = addrinfoErrno(gerrno).Temporary()
		}

return nil, &DNSError{Err: err.Error(), Name: name, IsNotFound: isErrorNoSuchHost, IsTemporary: isTemporary}
	}
	defer _C_freeaddrinfo(res)

for r := res; r != nil; r = *_C_ai_next(r) {
		// We only asked for SOCK_STREAM, but check anyhow.
		if *_C_ai_socktype(r) != _C_SOCK_STREAM {
			continue
		}
		switch *_C_ai_family(r) {
		case _C_AF_INET:
			sa := (*syscall.RawSockaddrInet4)(unsafe.Pointer(*_C_ai_addr(r)))
			addr := IPAddr{IP: copyIP(sa.Addr[:])}
			addrs = append(addrs, addr)
		case _C_AF_INET6:
			sa := (*syscall.RawSockaddrInet6)(unsafe.Pointer(*_C_ai_addr(r)))
			addr := IPAddr{IP: copyIP(sa.Addr[:]), Zone: zoneCache.name(int(sa.Scope_id))}
			addrs = append(addrs, addr)
		}
	}
	return addrs, nil
}

func cgoLookupIP(ctx context.Context, network, name string) (addrs []IPAddr, err error) {
	return doBlockingWithCtx(ctx, func() ([]IPAddr, error) {
		return cgoLookupHostIP(network, name)
	})
}

// These are roughly enough for the following:
//
//	 Source		Encoding			Maximum length of single name entry
//	 Unicast DNS		ASCII or			<=253 + a NUL terminator
//				Unicode in RFC 5892		252 * total number of labels + delimiters + a NUL terminator
//	 Multicast DNS	UTF-8 in RFC 5198 or		<=253 + a NUL terminator
//				the same as unicast DNS ASCII	<=253 + a NUL terminator
//	 Local database	various				depends on implementation
const (
	nameinfoLen    = 64
	maxNameinfoLen = 4096
)

func cgoLookupPTR(ctx context.Context, addr string) (names []string, err error) {
	ip, err := netip.ParseAddr(addr)
	if err != nil {
		return nil, &DNSError{Err: "invalid address", Name: addr}
	}
	sa, salen := cgoSockaddr(IP(ip.AsSlice()), ip.Zone())
	if sa == nil {
		return nil, &DNSError{Err: "invalid address " + ip.String(), Name: addr}
	}

return doBlockingWithCtx(ctx, func() ([]string, error) {
		return cgoLookupAddrPTR(addr, sa, salen)
	})
}

func cgoLookupAddrPTR(addr string, sa *_C_struct_sockaddr, salen _C_socklen_t) (names []string, err error) {
	acquireThread()
	defer releaseThread()

var gerrno int
	var b []byte
	for l := nameinfoLen; l <= maxNameinfoLen; l *= 2 {
		b = make([]byte, l)
		gerrno, err = cgoNameinfoPTR(b, sa, salen)
		if gerrno == 0 || gerrno != _C_EAI_OVERFLOW {
			break
		}
	}
	if gerrno != 0 {
		isErrorNoSuchHost := false
		isTemporary := false
		switch gerrno {
		case _C_EAI_SYSTEM:
			if err == nil { // see golang.org/issue/6232
				err = syscall.EMFILE
			}
		case _C_EAI_NONAME:
			err = errNoSuchHost
			isErrorNoSuchHost = true
		default:
			err = addrinfoErrno(gerrno)
			isTemporary = addrinfoErrno(gerrno).Temporary()
		}
		return nil, &DNSError{Err: err.Error(), Name: addr, IsTemporary: isTemporary, IsNotFound: isErrorNoSuchHost}
	}
	for i := 0; i < len(b); i++ {
		if b[i] == 0 {
			b = b[:i]
			break
		}
	}
	return []string{absDomainName(string(b))}, nil
}

func cgoSockaddr(ip IP, zone string) (*_C_struct_sockaddr, _C_socklen_t) {
	if ip4 := ip.To4(); ip4 != nil {
		return cgoSockaddrInet4(ip4), _C_socklen_t(syscall.SizeofSockaddrInet4)
	}
	if ip6 := ip.To16(); ip6 != nil {
		return cgoSockaddrInet6(ip6, zoneCache.index(zone)), _C_socklen_t(syscall.SizeofSockaddrInet6)
	}
	return nil, 0
}

func cgoLookupCNAME(ctx context.Context, name string) (cname string, err error, completed bool) {
	resources, err := resSearch(ctx, name, int(dnsmessage.TypeCNAME), int(dnsmessage.ClassINET))
	if err != nil {
		return
	}
	cname, err = parseCNAMEFromResources(resources)
	if err != nil {
		return "", err, false
	}
	return cname, nil, true
}

// resSearch will make a call to the 'res_nsearch' routine in the C library
// and parse the output as a slice of DNS resources.
func resSearch(ctx context.Context, hostname string, rtype, class int) ([]dnsmessage.Resource, error) {
	return doBlockingWithCtx(ctx, func() ([]dnsmessage.Resource, error) {
		return cgoResSearch(hostname, rtype, class)
	})
}

func cgoResSearch(hostname string, rtype, class int) ([]dnsmessage.Resource, error) {
	acquireThread()
	defer releaseThread()

resStateSize := unsafe.Sizeof(_C_struct___res_state{})
	var state *_C_struct___res_state
	if resStateSize > 0 {
		mem := _C_malloc(resStateSize)
		defer _C_free(mem)
		memSlice := unsafe.Slice((*byte)(mem), resStateSize)
		clear(memSlice)
		state = (*_C_struct___res_state)(unsafe.Pointer(&memSlice[0]))
	}
	if err := _C_res_ninit(state); err != nil {
		return nil, errors.New("res_ninit failure: " + err.Error())
	}
	defer _C_res_nclose(state)

// Some res_nsearch implementations (like macOS) do not set errno.
	// They set h_errno, which is not per-thread and useless to us.
	// res_nsearch returns the size of the DNS response packet.
	// But if the DNS response packet contains failure-like response codes,
	// res_search returns -1 even though it has copied the packet into buf,
	// giving us no way to find out how big the packet is.
	// For now, we are willing to take res_search's word that there's nothing
	// useful in the response, even though there *is* a response.
	bufSize := maxDNSPacketSize
	buf := (*_C_uchar)(_C_malloc(uintptr(bufSize)))
	defer _C_free(unsafe.Pointer(buf))

s, err := syscall.BytePtrFromString(hostname)
	if err != nil {
		return nil, err
	}

var size int
	for {
		size, _ = _C_res_nsearch(state, (*_C_char)(unsafe.Pointer(s)), class, rtype, buf, bufSize)
		if size <= 0 || size > 0xffff {
			return nil, errors.New("res_nsearch failure")
		}
		if size <= bufSize {
			break
		}

// Allocate a bigger buffer to fit the entire msg.
		_C_free(unsafe.Pointer(buf))
		bufSize = size
		buf = (*_C_uchar)(_C_malloc(uintptr(bufSize)))
	}

var p dnsmessage.Parser
	if _, err := p.Start(unsafe.Slice((*byte)(unsafe.Pointer(buf)), size)); err != nil {
		return nil, err
	}
	p.SkipAllQuestions()
	resources, err := p.AllAnswers()
	if err != nil {
		return nil, err
	}
	return resources, nil
}