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// Copyright 2013 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.
// +build linux
#include <errno.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/epoll.h>
#include "runtime.h"
#include "defs.h"
#ifndef EPOLLRDHUP
#define EPOLLRDHUP 0x2000
#endif
#ifndef EPOLL_CLOEXEC
#define EPOLL_CLOEXEC 02000000
#endif
typedef struct epoll_event EpollEvent;
static int32
runtime_epollcreate(int32 size)
{
int r;
r = epoll_create(size);
if(r >= 0)
return r;
return - errno;
}
static int32
runtime_epollcreate1(int32 flags)
{
int r;
r = epoll_create1(flags);
if(r >= 0)
return r;
return - errno;
}
static int32
runtime_epollctl(int32 epfd, int32 op, int32 fd, EpollEvent *ev)
{
int r;
r = epoll_ctl(epfd, op, fd, ev);
if(r >= 0)
return r;
return - errno;
}
static int32
runtime_epollwait(int32 epfd, EpollEvent *ev, int32 nev, int32 timeout)
{
int r;
r = epoll_wait(epfd, ev, nev, timeout);
if(r >= 0)
return r;
return - errno;
}
static void
runtime_closeonexec(int32 fd)
{
fcntl(fd, F_SETFD, FD_CLOEXEC);
}
static int32 epfd = -1; // epoll descriptor
void
runtime_netpollinit(void)
{
epfd = runtime_epollcreate1(EPOLL_CLOEXEC);
if(epfd >= 0)
return;
epfd = runtime_epollcreate(1024);
if(epfd >= 0) {
runtime_closeonexec(epfd);
return;
}
runtime_printf("netpollinit: failed to create descriptor (%d)\n", -epfd);
runtime_throw("netpollinit: failed to create descriptor");
}
int32
runtime_netpollopen(int32 fd, PollDesc *pd)
{
EpollEvent ev;
int32 res;
ev.events = EPOLLIN|EPOLLOUT|EPOLLRDHUP|EPOLLET;
ev.data.ptr = (void*)pd;
res = runtime_epollctl(epfd, EPOLL_CTL_ADD, fd, &ev);
return -res;
}
int32
runtime_netpollclose(int32 fd)
{
EpollEvent ev;
int32 res;
res = runtime_epollctl(epfd, EPOLL_CTL_DEL, fd, &ev);
return -res;
}
// polls for ready network connections
// returns list of goroutines that become runnable
G*
runtime_netpoll(bool block)
{
static int32 lasterr;
EpollEvent events[128], *ev;
int32 n, i, waitms, mode;
G *gp;
if(epfd == -1)
return nil;
waitms = -1;
if(!block)
waitms = 0;
retry:
n = runtime_epollwait(epfd, events, nelem(events), waitms);
if(n < 0) {
if(n != -EINTR && n != lasterr) {
lasterr = n;
runtime_printf("runtime: epollwait on fd %d failed with %d\n", epfd, -n);
}
goto retry;
}
gp = nil;
for(i = 0; i < n; i++) {
ev = &events[i];
if(ev->events == 0)
continue;
mode = 0;
if(ev->events & (EPOLLIN|EPOLLRDHUP|EPOLLHUP|EPOLLERR))
mode += 'r';
if(ev->events & (EPOLLOUT|EPOLLHUP|EPOLLERR))
mode += 'w';
if(mode)
runtime_netpollready(&gp, (void*)ev->data.ptr, mode);
}
if(block && gp == nil)
goto retry;
return gp;
}
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