Add fdwait routines.

src/libthread/fdwait.c

@@ -0,0 +1,250 @@
+#define NOPLAN9DEFINES
+#include <u.h>
+#include <libc.h>
+#include <thread.h>
+
+#include <errno.h>
+#include <poll.h>
+#include <unistd.h>
+#include <fcntl.h>
+
+/*
+ * Poll file descriptors in an idle loop.
+ */
+
+typedef struct Poll Poll;
+
+struct Poll
+{
+	Channel *c;	/* for sending back */
+};
+
+static Channel *sleepchan[64];
+static int sleeptime[64];
+static int nsleep;
+
+static struct pollfd pfd[64];
+static struct Poll polls[64];
+static int npoll;
+
+static void
+pollidle(void *v)
+{
+	int i, n, t;
+	uint now;
+
+	for(;; yield()){
+		//fprint(2, "poll %d:", npoll);
+		for(i=0; i<npoll; i++){
+			//fprint(2, " %d%c", pfd[i].fd, pfd[i].events==POLLIN ? 'r' : 'w');
+			pfd[i].revents = 0;
+		}
+		t = -1;
+		for(i=0; i<nsleep; i++){
+			now = p9nsec()/1000000;
+			n = sleeptime[i] - now;
+			if(n < 0)
+				n = 0;
+			if(t == -1 || n < t)
+				t = n;
+		}
+		//fprint(2, "\n");
+	
+		n = poll(pfd, npoll, t);
+		//fprint(2, "poll ret %d:", n);
+		now = p9nsec()/1000000;
+		for(i=0; i<nsleep; i++){
+			if((int)(sleeptime[i] - now) < 0){
+				nbsendul(sleepchan[i], 0);
+				nsleep--;
+				sleepchan[i] = sleepchan[nsleep];
+				sleeptime[i] = sleeptime[nsleep];
+				i--;
+			}
+		}
+				
+		if(n <= 0)
+			continue;
+		for(i=0; i<npoll; i++)
+			if(pfd[i].fd != -1 && pfd[i].revents){
+				//fprint(2, " %d", pfd[i].fd);
+				nbsendul(polls[i].c, 1);
+				pfd[i].fd = -1;
+				pfd[i].events = 0;
+				pfd[i].revents = 0;
+			}
+		//fprint(2, "\n");
+	}
+}
+
+void
+threadfdwaitsetup(void)
+{
+	static int setup = 0;
+
+	if(!setup){
+		setup = 1;
+		threadcreateidle(pollidle, nil, 16384);
+	}
+}
+
+void
+threadfdwait(int fd, int rw)
+{
+	int i;
+
+	struct {
+		Channel c;
+		ulong x;
+	} s;
+
+	threadfdwaitsetup();
+	chaninit(&s.c, sizeof(ulong), 1);
+	for(i=0; i<npoll; i++)
+		if(pfd[i].fd == -1)
+			break;
+	if(i==npoll){
+		if(npoll >= nelem(polls)){
+			fprint(2, "Too many polled fds.\n");
+			abort();
+		}
+		npoll++;
+	}
+
+	pfd[i].fd = fd;
+	pfd[i].events = rw=='r' ? POLLIN : POLLOUT;
+	polls[i].c = &s.c;
+	//threadstate("fdwait %d %d", f->fd, e);
+	recvul(&s.c);
+}
+
+void
+threadsleep(int ms)
+{
+	struct {
+		Channel c;
+		ulong x;
+	} s;
+
+	threadfdwaitsetup();
+	chaninit(&s.c, sizeof(ulong), 1);
+
+	sleepchan[nsleep] = &s.c;
+	sleeptime[nsleep++] = p9nsec()/1000000+ms;
+	recvul(&s.c);
+}
+
+void
+threadfdnoblock(int fd)
+{
+	fcntl(fd, F_SETFL, fcntl(fd, F_GETFL, 0)|O_NONBLOCK);
+}
+
+long
+threadread(int fd, void *a, long n)
+{
+	int nn;
+
+	threadfdnoblock(fd);
+again:
+	nn = read(fd, a, n);
+	if(nn < 0){
+		if(errno == EINTR)
+			goto again;
+		if(errno == EAGAIN || errno == EWOULDBLOCK){
+			threadfdwait(fd, 'r');
+			goto again;
+		}
+	}
+	return nn;
+}
+
+int
+threadrecvfd(int fd)
+{
+	int nn;
+
+	threadfdnoblock(fd);
+again:
+	nn = recvfd(fd);
+	if(nn < 0){
+		if(errno == EINTR)
+			goto again;
+		if(errno == EAGAIN || errno == EWOULDBLOCK){
+			threadfdwait(fd, 'r');
+			goto again;
+		}
+	}
+	return nn;
+}
+
+int
+threadsendfd(int fd, int sfd)
+{
+	int nn;
+
+	threadfdnoblock(fd);
+again:
+	nn = sendfd(fd, sfd);
+	if(nn < 0){
+		if(errno == EINTR)
+			goto again;
+		if(errno == EAGAIN || errno == EWOULDBLOCK){
+			threadfdwait(fd, 'w');
+			goto again;
+		}
+	}
+	return nn;
+}
+
+long
+threadreadn(int fd, void *a, long n)
+{
+	int tot, nn;
+
+	for(tot = 0; tot<n; tot+=nn){
+		nn = threadread(fd, (char*)a+tot, n-tot);
+		if(nn <= 0){
+			if(tot == 0)
+				return nn;
+			return tot;
+		}
+	}
+	return tot;
+}
+
+long
+_threadwrite(int fd, const void *a, long n)
+{
+	int nn;
+
+	threadfdnoblock(fd);
+again:
+	nn = write(fd, a, n);
+	if(nn < 0){
+		if(errno == EINTR)
+			goto again;
+		if(errno == EAGAIN || errno == EWOULDBLOCK){
+			threadfdwait(fd, 'w');
+			goto again;
+		}
+	}
+	return nn;
+}
+
+long
+threadwrite(int fd, const void *a, long n)
+{
+	int tot, nn;
+
+	for(tot = 0; tot<n; tot+=nn){
+		nn = _threadwrite(fd, (char*)a+tot, n-tot);
+		if(nn <= 0){
+			if(tot == 0)
+				return nn;
+			return tot;
+		}
+	}
+	return tot;
+}
+