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Pipes

Use Pipes for IPC (Inter Process Communications).
A pipe is a data communication conduit for connected  2 processes.
Like a pip stuff can go in one end, and come out the other.
There are 2 types of pipes
  • Named Pipes - Very flexible and can connect processes across a network.
  • Anonymous Pipes - Simpler and for local machine only.
Reference

Named Pipes

  • A pipe server connects one or more pipe client. One or two way communications.
  • Pipe server - a process that creates a named pipe.
  • Pipe client - a process that connects to an instance of a named pipe.
  • For Local PC - deny access to NT AUTHORITY\NETWORK or switch to local RPC.
Calls
  • Server app names a pipe using CreateNamedPipe to create one or more instances of a named pipe.
    • Using access mode: PIPE_ACCESS_INBOUND or PIPE_ACCESS_OUTBOUND or PIPE_ACCESS_DUPLEX
  • Pipe clients specify the pipe name when they call the CreateFile or CallNamedPipe function to connect to an instance of the named pipe.
    • Using Equivalent generic access right - GENERIC_WRITE or GENERIC_READ or GENERIC_READ | GENERIC_WRITE
  • CreateFile, WaitNamedPipe, or CallNamedPipe function requires a pipename
    • in the form \\ServerName\pipe\PipeName
    • or for local PC only use a . for the server name - \\.\pipe\PipeName
  • Pipe attributes
    • FILE_READ_ATTRIBUTES - allows clients to read access right
    • FILE_WRITE_ATTRIBUTES - allows you to change attributes.
  • A pipe server often passes the pipe name to its pipe clients so they can connect to the pipe. Otherwise, the clients must know the pipe name at compile time.
  • Overlapped mode allows messages to be sent simultaneously
    • The CreateFile function allows the pipe client to set overlapped mode (FILE_FLAG_OVERLAPPED) .


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