- djm@cvs.openbsd.org 2010/01/12 00:58:25
[monitor_fdpass.c]
avoid spinning when fd passing on nonblocking sockets by calling poll()
in the EINTR/EAGAIN path, much like we do in atomicio; ok dtucker@
diff --git a/monitor_fdpass.c b/monitor_fdpass.c
index 4b9a066..56d3afd 100644
--- a/monitor_fdpass.c
+++ b/monitor_fdpass.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: monitor_fdpass.c,v 1.18 2008/11/30 11:59:26 dtucker Exp $ */
+/* $OpenBSD: monitor_fdpass.c,v 1.19 2010/01/12 00:58:25 djm Exp $ */
/*
* Copyright 2001 Niels Provos <provos@citi.umich.edu>
* All rights reserved.
@@ -34,6 +34,7 @@
#endif
#include <errno.h>
+#include <poll.h>
#include <string.h>
#include <stdarg.h>
@@ -55,6 +56,7 @@
struct iovec vec;
char ch = '\0';
ssize_t n;
+ struct pollfd pfd;
memset(&msg, 0, sizeof(msg));
#ifdef HAVE_ACCRIGHTS_IN_MSGHDR
@@ -75,9 +77,13 @@
msg.msg_iov = &vec;
msg.msg_iovlen = 1;
- while ((n = sendmsg(sock, &msg, 0)) == -1 && (errno == EAGAIN ||
- errno == EINTR))
+ pfd.fd = sock;
+ pfd.events = POLLOUT;
+ while ((n = sendmsg(sock, &msg, 0)) == -1 &&
+ (errno == EAGAIN || errno == EINTR)) {
debug3("%s: sendmsg(%d): %s", __func__, fd, strerror(errno));
+ (void)poll(&pfd, 1, -1);
+ }
if (n == -1) {
error("%s: sendmsg(%d): %s", __func__, fd,
strerror(errno));
@@ -112,6 +118,7 @@
ssize_t n;
char ch;
int fd;
+ struct pollfd pfd;
memset(&msg, 0, sizeof(msg));
vec.iov_base = &ch;
@@ -126,9 +133,13 @@
msg.msg_controllen = sizeof(cmsgbuf.buf);
#endif
- while ((n = recvmsg(sock, &msg, 0)) == -1 && (errno == EAGAIN ||
- errno == EINTR))
+ pfd.fd = sock;
+ pfd.events = POLLIN;
+ while ((n = recvmsg(sock, &msg, 0)) == -1 &&
+ (errno == EAGAIN || errno == EINTR)) {
debug3("%s: recvmsg: %s", __func__, strerror(errno));
+ (void)poll(&pfd, 1, -1);
+ }
if (n == -1) {
error("%s: recvmsg: %s", __func__, strerror(errno));
return -1;