add (untested) implementation of recvmsg in terms of WSARecvMsg

[catta] / src / compat / windows / wincompat.h

diff --git a/src/compat/windows/wincompat.h b/src/compat/windows/wincompat.h
index 531aadd8b0c47e1ae9ec503827773c3b63295090..6510183a870b86f95644cd6b7c64ce9bfdff9f19 100644 (file)
--- a/src/compat/windows/wincompat.h
+++ b/src/compat/windows/wincompat.h
@@ -1,15 +1,76 @@
 #ifndef foowincompatfoo
 #define foowincompatfoo
 
+// This file and its companion wincompat.c provide some Posix interfaces to
+// Windows APIs so the rest of the code can keep using them.
+
+
+// require at least Windows Vista
 #undef WINVER
 #undef _WIN32_WINNT
-
-#define WINVER 0x0600       // Vista
+#define WINVER 0x0600
 #define _WIN32_WINNT WINVER
 
 #include <winsock2.h>
 #include <ws2tcpip.h>
+#include <mswsock.h>
+
+
+// Winsock doesn't have recvmsg/sendmsg but offers the same functionality
+// with WSARecvMsg/WSASendMsg, so we implement the former in terms of the
+// latter.
+
+struct iovec {                   /* Scatter/gather array items */
+   void  *iov_base;              /* Starting address */
+   size_t iov_len;               /* Number of bytes to transfer */
+};
+
+struct msghdr {
+   void         *msg_name;       /* optional address */
+   socklen_t     msg_namelen;    /* size of address */
+   struct iovec *msg_iov;        /* scatter/gather array */
+   size_t        msg_iovlen;     /* # elements in msg_iov */
+   void         *msg_control;    /* ancillary data, see below */
+   size_t        msg_controllen; /* ancillary data buffer len */
+   int           msg_flags;      /* flags on received message */
+};
+
+// MSDN says this struct is called wsacmsghdr but MingW uses _WSACMSGHDR.
+// TODO: Verify what it is on actual Windows.
+// cf. http://msdn.microsoft.com/en-us/library/ms741645(v=vs.85).aspx
+#ifdef __MINGW32__
+#define cmsghdr _WSACMSGHDR     // as in 'struct cmsghdr'
+#else
+#define cmsghdr wsacmsghdr      // as in 'struct cmsghdr'
+#endif
+
+static inline struct cmsghdr *CMSG_FIRSTHDR(struct msghdr *m) {
+    WSAMSG wm;
+    wm.Control.len = m->msg_controllen;
+    wm.Control.buf = m->msg_control;
+    return WSA_CMSG_FIRSTHDR(&wm);
+}
+
+static inline struct cmsghdr *CMSG_NXTHDR(struct msghdr *m, struct cmsghdr *c) {
+    WSAMSG wm;
+    wm.Control.len = m->msg_controllen;
+    wm.Control.buf = m->msg_control;
+    return WSA_CMSG_NXTHDR(&wm, c);
+}
+
+#define CMSG_SPACE(len) WSA_CMSG_SPACE(len)
+#define CMSG_LEN(len) WSA_CMSG_LEN(len)
+
+// we're going to be naughty and redefine CMSG_DATA as an alias even though it
+// is also a constant defined in wincrypt.h which we don't care about.
+#undef CMSG_DATA
+#define CMSG_DATA(c) WSA_CMSG_DATA(c)
+
+ssize_t recvmsg(int sockfd, struct msghdr *msg, int flags);
+ssize_t sendmsg(int sockfd, const struct msghdr *msg, int flags);
+
 
+// Windows logically doesn't have uname, so we supply a replacement.
 
 struct utsname {
    char sysname[9];    /* Operating system name (e.g., "Linux") */