1 // Copyright 2013 The Go Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style
3 // license that can be found in the LICENSE file.
4
5 // +build darwin
6
7 #include "runtime.h"
8 #include "defs_GOOS_GOARCH.h"
9
10 // Integrated network poller (kqueue-based implementation).
11
12 int32 runtime_kqueue(void);
13 int32 runtime_kevent(int32, Kevent*, int32, Kevent*, int32, Timespec*);
14 void runtime_closeonexec(int32);
15
16 static int32 kq = -1;
17
18 void
runtime_netpollinit(void)19 runtime_netpollinit(void)
20 {
21 kq = runtime_kqueue();
22 if(kq < 0) {
23 runtime_printf("netpollinit: kqueue failed with %d\n", -kq);
24 runtime_throw("netpollinit: kqueue failed");
25 }
26 runtime_closeonexec(kq);
27 }
28
29 int32
runtime_netpollopen(int32 fd,PollDesc * pd)30 runtime_netpollopen(int32 fd, PollDesc *pd)
31 {
32 Kevent ev[2];
33 int32 n;
34
35 // Arm both EVFILT_READ and EVFILT_WRITE in edge-triggered mode (EV_CLEAR)
36 // for the whole fd lifetime. The notifications are automatically unregistered
37 // when fd is closed.
38 ev[0].ident = fd;
39 ev[0].filter = EVFILT_READ;
40 ev[0].flags = EV_ADD|EV_RECEIPT|EV_CLEAR;
41 ev[0].fflags = 0;
42 ev[0].data = 0;
43 ev[0].udata = (byte*)pd;
44 ev[1] = ev[0];
45 ev[1].filter = EVFILT_WRITE;
46 n = runtime_kevent(kq, ev, 2, ev, 2, nil);
47 if(n < 0)
48 return -n;
49 if(n != 2 ||
50 (ev[0].flags&EV_ERROR) == 0 || ev[0].ident != fd || ev[0].filter != EVFILT_READ ||
51 (ev[1].flags&EV_ERROR) == 0 || ev[1].ident != fd || ev[1].filter != EVFILT_WRITE)
52 return EFAULT; // just to mark out from other errors
53 if(ev[0].data != 0)
54 return ev[0].data;
55 if(ev[1].data != 0)
56 return ev[1].data;
57 return 0;
58 }
59
60 int32
runtime_netpollclose(int32 fd)61 runtime_netpollclose(int32 fd)
62 {
63 // Don't need to unregister because calling close()
64 // on fd will remove any kevents that reference the descriptor.
65 USED(fd);
66 return 0;
67 }
68
69 // Polls for ready network connections.
70 // Returns list of goroutines that become runnable.
71 G*
runtime_netpoll(bool block)72 runtime_netpoll(bool block)
73 {
74 static int32 lasterr;
75 Kevent events[64], *ev;
76 Timespec ts, *tp;
77 int32 n, i;
78 G *gp;
79
80 if(kq == -1)
81 return nil;
82 tp = nil;
83 if(!block) {
84 ts.tv_sec = 0;
85 ts.tv_nsec = 0;
86 tp = &ts;
87 }
88 gp = nil;
89 retry:
90 n = runtime_kevent(kq, nil, 0, events, nelem(events), tp);
91 if(n < 0) {
92 if(n != -EINTR && n != lasterr) {
93 lasterr = n;
94 runtime_printf("runtime: kevent on fd %d failed with %d\n", kq, -n);
95 }
96 goto retry;
97 }
98 for(i = 0; i < n; i++) {
99 ev = &events[i];
100 if(ev->filter == EVFILT_READ)
101 runtime_netpollready(&gp, (PollDesc*)ev->udata, 'r');
102 if(ev->filter == EVFILT_WRITE)
103 runtime_netpollready(&gp, (PollDesc*)ev->udata, 'w');
104 }
105 if(block && gp == nil)
106 goto retry;
107 return gp;
108 }
109