// Might return short reads
unsafe int ReadShort(byte[] buffer, int offset, int length, UnixFDArray fdArray)
{
if (length < 0 || offset < 0 || length + offset < length || length + offset > buffer.Length)
{
throw new ArgumentException();
fixed(byte *ptr = buffer, cmsgPtr = cmsgBuffer)
{
var iovecs = new Iovec[] {
new Iovec {
iov_base = (IntPtr)(ptr + offset),
iov_len = (ulong)length,
},
};
var msghdr = new Msghdr {
msg_iov = iovecs,
msg_iovlen = 1,
msg_control = cmsgBuffer,
msg_controllen = cmsgBuffer.Length,
};
long r;
do
{
r = Syscall.recvmsg((int)SocketHandle, msghdr, 0);
} while (UnixMarshal.ShouldRetrySyscall((int)r));
for (long cOffset = Syscall.CMSG_FIRSTHDR(msghdr); cOffset != -1; cOffset = Syscall.CMSG_NXTHDR(msghdr, cOffset))
{
var recvHdr = Cmsghdr.ReadFromBuffer(msghdr, cOffset);
if (recvHdr.cmsg_level != UnixSocketProtocol.SOL_SOCKET)
{
continue;
}
if (recvHdr.cmsg_type != UnixSocketControlMessage.SCM_RIGHTS)
{
continue;
}
var recvDataOffset = Syscall.CMSG_DATA(msghdr, cOffset);
var bytes = recvHdr.cmsg_len - (recvDataOffset - cOffset);
var fdCount = bytes / sizeof(int);
for (int i = 0; i < fdCount; i++)
{
fdArray.FDs.Add(new UnixFD(((int *)(cmsgPtr + recvDataOffset))[i]));
}
}
if ((msghdr.msg_flags & MessageFlags.MSG_CTRUNC) != 0)
{
throw new Exception("Control message truncated (probably file descriptors lost)");
}
return((int)r);
}
}
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();
}
}
}
});
});
}