Current ovs matser has included sendmmsg declaration in
include/sparse/sys/socket.h
int sendmmsg(int, struct mmsghdr *, unsigned int, unsigned int);
I saw "+^L" in your patch.
--- a/lib/socket-util.c
+++ b/lib/socket-util.c
@@ -1283,3 +1283,59 @@ wrap_sendmmsg(int fd, struct mmsghdr *msgs, unsigned
int n, unsigned int flags)
}
#endif
#endif
+^L
+#ifndef _WIN32 /* Avoid using recvmsg on Windows entirely. */
+#undef recvmmsg
+int
+wrap_recvmmsg(int fd, struct mmsghdr *msgs, unsigned int n,
+ int flags, struct timespec *timeout)
+{
+ovs_assert(!timeout); /* XXX not emulated */
+
+static bool recvmmsg_broken = false;
+if (!recvmmsg_broken) {
+int save_errno = errno;
+int retval = recvmmsg(fd, msgs, n, flags, timeout);
+if (retval >= 0 || errno != ENOSYS) {
+return retval;
+}
+recvmmsg_broken = true;
+errno = save_errno;
+}
+return emulate_recvmmsg(fd, msgs, n, flags, timeout);
+}
+#endif
I don't understand why call recvmmsg here although we have known recvmmsg
isn't defined, I don't think "static bool recvmmsg_broken" is thread-safe. I
think we can completely remove the below part if we do know recvmmsg isn't
defined (I think autoconf can detect it very precisely, we needn't to do
runtime check for this)
+static bool recvmmsg_broken = false;
+if (!recvmmsg_broken) {
+int save_errno = errno;
+int retval = recvmmsg(fd, msgs, n, flags, timeout);
+if (retval >= 0 || errno != ENOSYS) {
+return retval;
+}
+recvmmsg_broken = true;
+errno = save_errno;
+}
-邮件原件-
发件人: Ben Pfaff [mailto:b...@ovn.org]
发送时间: 2019年12月18日 4:39
收件人: d...@openvswitch.org
抄送: Ben Pfaff ; Yi Yang (杨�D)-云服务集团
主题: [PATCH] socket-util: Introduce emulation and wrapper for recvmmsg().
Not every system will have recvmmsg(), so introduce compatibility code that
will allow it to be used blindly from the rest of the tree.
This assumes that recvmmsg() and sendmmsg() are either both present or both
absent in system libraries and headers.
CC: Yi Yang
Signed-off-by: Ben Pfaff
---
I haven't actually tested this!
include/sparse/sys/socket.h | 7 -
lib/socket-util.c | 56 +
lib/socket-util.h | 24 +---
3 files changed, 76 insertions(+), 11 deletions(-)
diff --git a/include/sparse/sys/socket.h b/include/sparse/sys/socket.h index
4178f57e2bda..6ff245ae939b 100644
--- a/include/sparse/sys/socket.h
+++ b/include/sparse/sys/socket.h
@@ -27,6 +27,7 @@
typedef unsigned short int sa_family_t; typedef __socklen_t socklen_t;
+struct timespec;
struct sockaddr {
sa_family_t sa_family;
@@ -126,7 +127,8 @@ enum {
MSG_PEEK,
MSG_TRUNC,
MSG_WAITALL,
-MSG_DONTWAIT
+MSG_DONTWAIT,
+MSG_WAITFORONE
};
enum {
@@ -171,4 +173,7 @@ int sockatmark(int); int socket(int, int, int); int
socketpair(int, int, int, int[2]);
+int sendmmsg(int, struct mmsghdr *, unsigned int, int); int
+recvmmsg(int, struct mmsghdr *, unsigned int, int, struct timespec *);
+
#endif /* for sparse */
diff --git a/lib/socket-util.c b/lib/socket-util.c index
6b7378de934b..f6f6f3b0a33f 100644
--- a/lib/socket-util.c
+++ b/lib/socket-util.c
@@ -1283,3 +1283,59 @@ wrap_sendmmsg(int fd, struct mmsghdr *msgs, unsigned
int n, unsigned int flags) } #endif #endif
+
+#ifndef _WIN32 /* Avoid using recvmsg on Windows entirely. */ static
+int emulate_recvmmsg(int fd, struct mmsghdr *msgs, unsigned int n,
+ int flags, struct timespec *timeout OVS_UNUSED) {
+ovs_assert(!timeout); /* XXX not emulated */
+
+bool waitforone = flags & MSG_WAITFORONE;
+flags &= ~MSG_WAITFORONE;
+
+for (unsigned int i = 0; i < n; i++) {
+ssize_t retval = recvmsg(fd, [i].msg_hdr, flags);
+if (retval < 0) {
+return i ? i : retval;
+}
+msgs[i].msg_len = retval;
+
+if (waitforone) {
+flags |= MSG_DONTWAIT;
+}
+}
+return n;
+}
+
+#ifndef HAVE_SENDMMSG
+int
+recvmmsg(int fd, struct mmsghdr *msgs, unsigned int n,
+ int flags, struct timespec *timeout) {
+return emulate_recvmmsg(fd, msgs, n, flags, timeout); } #else
+/* recvmmsg was redefined in lib/socket-util.c, should undef recvmmsg
+here
+ * to avoid recursion */
+#undef recvmmsg
+int
+wrap_recvmmsg(int fd, struct mmsghdr *msgs, unsigned int n,
+ int flags, struct timespec *timeout) {
+ovs_assert(!timeout); /* XXX not emulated */
+
+static bool recvmmsg_broken = false;
+if (!recvmmsg_broken) {
+int save_errno = errno;
+int retval = recvmmsg(fd, msgs, n, flags, timeout);
+if (retval >= 0 || errno != ENOSYS) {
+return retval;
+}
+recvmmsg_broken = true;
+errno = save_errno;
+}
+return emulate_recvmmsg(fd, msgs, n, flags, timeout); } #endif
+#endif
diff --git
