public unsafe void ControlMsg(bool useMultipleControlMessages)
{
// Create two socket pairs and send inner_so1 and inner_so2 over the other socket pair using SCM_RIGHTS
WithSocketPair((inner_so1, inner_so2) => {
WithSocketPair((so1, so2) => {
byte[] cmsg;
Msghdr msghdr1;
long offset;
if (useMultipleControlMessages)
{
// Create two SCM_RIGHTS control messages
cmsg = new byte[2 * Syscall.CMSG_SPACE(sizeof(int))];
var hdr = new Cmsghdr {
cmsg_len = (long)Syscall.CMSG_LEN(sizeof(int)),
cmsg_level = UnixSocketProtocol.SOL_SOCKET,
cmsg_type = UnixSocketControlMessage.SCM_RIGHTS,
};
msghdr1 = new Msghdr {
msg_control = cmsg,
msg_controllen = cmsg.Length,
};
offset = 0;
hdr.WriteToBuffer(msghdr1, offset);
var dataOffset = Syscall.CMSG_DATA(msghdr1, offset);
fixed(byte *ptr = msghdr1.msg_control)
{
((int *)(ptr + dataOffset))[0] = inner_so1;
}
offset = (long)Syscall.CMSG_SPACE(sizeof(int));
hdr.WriteToBuffer(msghdr1, offset);
dataOffset = Syscall.CMSG_DATA(msghdr1, offset);
fixed(byte *ptr = msghdr1.msg_control)
{
((int *)(ptr + dataOffset))[0] = inner_so2;
}
}
else
{
// Create one SCM_RIGHTS control message
cmsg = new byte[Syscall.CMSG_SPACE(2 * sizeof(int))];
var hdr = new Cmsghdr {
cmsg_len = (long)Syscall.CMSG_LEN(2 * sizeof(int)),
cmsg_level = UnixSocketProtocol.SOL_SOCKET,
cmsg_type = UnixSocketControlMessage.SCM_RIGHTS,
};
msghdr1 = new Msghdr {
msg_control = cmsg,
msg_controllen = cmsg.Length,
};
offset = 0;
hdr.WriteToBuffer(msghdr1, offset);
var dataOffset = Syscall.CMSG_DATA(msghdr1, offset);
fixed(byte *ptr = msghdr1.msg_control)
{
((int *)(ptr + dataOffset))[0] = inner_so1;
((int *)(ptr + dataOffset))[1] = inner_so2;
}
}
long ret;
var buffer1 = new byte[] { 42, 43, 44 };
fixed(byte *ptr_buffer1 = buffer1)
{
var iovecs1 = new Iovec[] {
new Iovec {
iov_base = (IntPtr)ptr_buffer1,
iov_len = (ulong)buffer1.Length,
},
};
msghdr1.msg_iov = iovecs1;
msghdr1.msg_iovlen = 1;
// Send message twice
ret = Syscall.sendmsg(so1, msghdr1, 0);
if (ret < 0)
{
UnixMarshal.ThrowExceptionForLastError();
}
ret = Syscall.sendmsg(so1, msghdr1, 0);
if (ret < 0)
{
UnixMarshal.ThrowExceptionForLastError();
}
}
// Receive without control message buffer
var buffer2 = new byte[1024];
var msghdr2 = new Msghdr {
};
fixed(byte *ptr_buffer2 = buffer2)
{
var iovecs2 = new Iovec[] {
new Iovec {
iov_base = (IntPtr)ptr_buffer2,
iov_len = (ulong)buffer2.Length,
},
};
msghdr2.msg_iov = iovecs2;
msghdr2.msg_iovlen = 1;
ret = Syscall.recvmsg(so2, msghdr2, 0);
}
if (ret < 0)
{
UnixMarshal.ThrowExceptionForLastError();
}
if (useMultipleControlMessages) // This assertion fails on OSX for some reason
{
Assert.IsTrue((msghdr2.msg_flags & MessageFlags.MSG_CTRUNC) != 0); // Control message has been truncated
}
Assert.AreEqual(buffer1.Length, ret);
for (int i = 0; i < buffer1.Length; i++)
{
Assert.AreEqual(buffer1[i], buffer2[i]);
}
// Receive with control message buffer
buffer2 = new byte[1024];
var cmsg2 = new byte[1024];
msghdr2 = new Msghdr {
msg_control = cmsg2,
msg_controllen = cmsg2.Length,
};
fixed(byte *ptr_buffer2 = buffer2)
{
var iovecs2 = new Iovec[] {
new Iovec {
iov_base = (IntPtr)ptr_buffer2,
iov_len = (ulong)buffer2.Length,
},
};
msghdr2.msg_iov = iovecs2;
msghdr2.msg_iovlen = 1;
ret = Syscall.recvmsg(so2, msghdr2, 0);
}
if (ret < 0)
{
UnixMarshal.ThrowExceptionForLastError();
}
var fds = new global::System.Collections.Generic.List <int> ();
for (offset = Syscall.CMSG_FIRSTHDR(msghdr2); offset != -1; offset = Syscall.CMSG_NXTHDR(msghdr2, offset))
{
var recvHdr = Cmsghdr.ReadFromBuffer(msghdr2, offset);
var recvDataOffset = Syscall.CMSG_DATA(msghdr2, offset);
var bytes = recvHdr.cmsg_len - (recvDataOffset - offset);
Assert.AreEqual(bytes % sizeof(int), 0);
var fdCount = bytes / sizeof(int);
fixed(byte *ptr = msghdr2.msg_control)
for (int i = 0; i < fdCount; i++)
{
fds.Add(((int *)(ptr + recvDataOffset))[i]);
}
}
try {
Assert.IsTrue((msghdr2.msg_flags & MessageFlags.MSG_CTRUNC) == 0); // Control message has not been truncated
Assert.AreEqual(buffer1.Length, ret);
for (int i = 0; i < buffer1.Length; i++)
{
Assert.AreEqual(buffer1[i], buffer2[i]);
}
Assert.AreEqual(fds.Count, 2);
// Send message over the first received fd and receive it over inner_so2
var buffer3 = new byte[] { 16, 17 };
ret = Syscall.send(fds[0], buffer3, (ulong)buffer3.Length, 0);
if (ret < 0)
{
UnixMarshal.ThrowExceptionForLastError();
}
var buffer4 = new byte[1024];
ret = Syscall.recv(inner_so2, buffer4, (ulong)buffer4.Length, 0);
if (ret < 0)
{
UnixMarshal.ThrowExceptionForLastError();
}
Assert.AreEqual(buffer3.Length, ret);
for (int i = 0; i < buffer3.Length; i++)
{
Assert.AreEqual(buffer3[i], buffer4[i]);
}
// Send message over inner_so1 and receive it second received fd
var buffer5 = new byte[] { 10, 40, 0, 1 };
ret = Syscall.send(inner_so1, buffer5, (ulong)buffer5.Length, 0);
if (ret < 0)
{
UnixMarshal.ThrowExceptionForLastError();
}
var buffer6 = new byte[1024];
ret = Syscall.recv(fds[1], buffer6, (ulong)buffer6.Length, 0);
if (ret < 0)
{
UnixMarshal.ThrowExceptionForLastError();
}
Assert.AreEqual(buffer5.Length, ret);
for (int i = 0; i < buffer5.Length; i++)
{
Assert.AreEqual(buffer5[i], buffer6[i]);
}
} finally {
foreach (var fd in fds)
{
if (Syscall.close(fd) < 0)
{
UnixMarshal.ThrowExceptionForLastError();
}
}
}
});
});
}
// Send the two buffers and the FDs using sendmsg(), don't handle short writes
// length1 + length2 must not be 0
public unsafe long SendmsgShort(byte[] buffer1, long offset1, long length1,
byte[] buffer2, long offset2, long length2,
DBus.Protocol.UnixFDArray fds)
{
//Console.WriteLine ("SendmsgShort (X, {0}, {1}, {2}, {3}, {4}, {5})", offset1, length1, buffer2 == null ? "-" : "Y", offset2, length2, fds == null ? "-" : "" + fds.FDs.Count);
AssertValidBuffer(buffer1, offset1, length1);
if (buffer2 == null)
{
if (length2 != 0)
{
throw new ArgumentOutOfRangeException("length2", "!= 0 while buffer2 == null");
}
offset2 = 0;
}
else
{
AssertValidBuffer(buffer2, offset2, length2);
}
fixed(byte *ptr1 = buffer1, ptr2 = buffer2)
{
var iovecs = new Iovec[] {
new Iovec {
iov_base = (IntPtr)(ptr1 + offset1),
iov_len = (ulong)length1,
},
new Iovec {
iov_base = (IntPtr)(ptr2 + offset2),
iov_len = (ulong)length2,
},
};
/* Simulate short writes
* if (iovecs[0].iov_len == 0) {
* iovecs[1].iov_len = Math.Min (iovecs[1].iov_len, 5);
* } else {
* iovecs[0].iov_len = Math.Min (iovecs[0].iov_len, 5);
* iovecs[1].iov_len = 0;
* }
*/
byte[] cmsg = null;
// Create copy of FDs to prevent the user from Dispose()ing the
// FDs in another thread between writing the FDs into the cmsg
// buffer and calling sendmsg()
using (var fds2 = fds == null ? null : fds.Clone()) {
int fdCount = fds2 == null ? 0 : fds2.FDs.Count;
if (fdCount != 0)
{
// Create one SCM_RIGHTS control message
cmsg = new byte[Syscall.CMSG_SPACE((uint)fdCount * sizeof(int))];
}
var msghdr = new Msghdr {
msg_iov = iovecs,
msg_iovlen = length2 == 0 ? 1 : 2,
msg_control = cmsg,
msg_controllen = cmsg == null ? 0 : cmsg.Length,
};
if (fdCount != 0)
{
var hdr = new Cmsghdr {
cmsg_len = (long)Syscall.CMSG_LEN((uint)fdCount * sizeof(int)),
cmsg_level = UnixSocketProtocol.SOL_SOCKET,
cmsg_type = UnixSocketControlMessage.SCM_RIGHTS,
};
hdr.WriteToBuffer(msghdr, 0);
var dataOffset = Syscall.CMSG_DATA(msghdr, 0);
fixed(byte *ptr = cmsg)
{
for (int i = 0; i < fdCount; i++)
{
((int *)(ptr + dataOffset))[i] = fds2.FDs[i].Handle;
}
}
}
long r;
do
{
r = Syscall.sendmsg(fd, msghdr, MessageFlags.MSG_NOSIGNAL);
} while (UnixMarshal.ShouldRetrySyscall((int)r));
if (r < 0)
{
UnixMarshal.ThrowExceptionForLastError();
}
if (r == 0)
{
throw new Exception("sendmsg() returned 0");
}
return(r);
}
}
}
