General socket operations

MiniGUI-Processes uses UNIX domain socket to build the communication between the server and the clients. More...

Macros
#define	sock_write(fd, buff, count)   sock_write_t(fd, buff, count, 0)
	The blocking version of sock_write_t function. More...
#define	sock_read(fd, buff, count)   sock_read_t(fd, buff, count, 0)
	The blocking version of sock_read_t function. More...

Functions
MG_EXPORT int	serv_listen (const char *name)
	Creates a listen socket. More...
MG_EXPORT int	serv_accept (int listenfd, pid_t *pidptr, uid_t *uidptr)
	Waits for a client connection to arrive, and accept it. More...
MG_EXPORT int	cli_conn (const char *name, char project)
	Used by clients to connect to a server. More...
MG_EXPORT ssize_t	sock_read_t (int fd, void *buff, size_t count, DWORD timeout)
	Reads data from socket. More...

Detailed Description

MiniGUI-Processes uses UNIX domain socket to build the communication between the server and the clients.

You can also use the underlay interfaces which MiniGUI uses to create your own UNIX domain socket.

Example:

#define LISTEN_SOCKET    "/var/tmp/mysocket"
 
static int listen_fd;
 
BOOL listen_socket (HWND hwnd)
{
    if ((listen_fd = serv_listen (LISTEN_SOCKET)) < 0)
        return FALSE;
    return RegisterListenFD (fd, POLL_IN, hwnd, NULL);
}
 
/*
 * When the server receives the request to connect from a client,
 * the window hwnd will receive a MSG_FDEVENT message.
 * Now the server can accept the request.
 */
LRESULT MyWndProc (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    switch (message) {
 
        ...
 
        case MSG_FDEVENT:
             if (LOWORD (wParam) == listen_fd) {
                  /* This message comes from the listen socket fd. */
                  pid_t pid;
                  uid_t uid;
                  int conn_fd;
                  conn_fd = serv_accept (listen_fd, &pid, &uid);
                  if (conn_fd >= 0) {
                       RegisterListenFD (conn_fd, POLL_IN, hwnd, NULL);
                  }
             }
             else {
                  /* Client send a request. */
                  int fd = LOWORD(wParam);
                  /* Handle the request from client. */
                  sock_read_t (fd, ...);
                  sock_write_t (fd, ....);
             }
        break;
 
        ...
 
    }
}
 
/*
 * Clients can use the following code to connect itself to the server.
 */
 
    int conn_fd;
 
    if ((conn_fd  = cli_conn (LISTEN_SOCKET, 'b')) >= 0) {
        /* Send a request to the server. */
        sock_write_t (fd, ....);
        /* Get the reply from the server. */
        sock_read_t (fd, ....);
    }

Macro Definition Documentation

sock_read

#define sock_read	(		fd,
			buff,
			count
	)		sock_read_t(fd, buff, count, 0)

The blocking version of sock_read_t function.

See also

sock_read_t

Definition at line 2444 of file minigui.h.

sock_write

#define sock_write	(		fd,
			buff,
			count
	)		sock_write_t(fd, buff, count, 0)

The blocking version of sock_write_t function.

See also

sock_write_t

Definition at line 2436 of file minigui.h.

Function Documentation

cli_conn()

int cli_conn	(	const char *	name,
		char	project
	)

Used by clients to connect to a server.

This function is used by clients to connect to a server.

The created socket will be located at the directory '/var/tmp', and with name of '/var/tmp/xxxxx-c', where 'xxxxx' is the pid of client. and 'c' is a character to distinguish different projects.

Note that MiniGUI itself uses 'a' as the project character to create socket between 'mginit' and clients.

Parameters

name	The name of the well-known listen socket (created by server).
project	A character to distinguish different projects (Do NOT use 'a').

Returns

The new connected fd if all OK, < 0 on error.

See also

serv_listen, serv_accept

serv_accept()

int serv_accept	(	int	listenfd,
		pid_t *	pidptr,
		uid_t *	uidptr
	)

Waits for a client connection to arrive, and accept it.

This function is used by the server to wait a connection and accept it.

After creating a listening socket by calling serv_listen, you can call this function to create a connection with a client. We also obtain the client's PID and UID from the pathname that it must bind before calling us.

Parameters

listenfd	The fd of listen socket.
pidptr	The client PID will be saved to this buffer when this function returns.
uidptr	The client UID will be saved to this buffer when this function returns.

Returns

The new connected fd if all OK, < 0 on error.

See also

serv_listen, cli_conn

serv_listen()

int serv_listen

(

const char *

name

)

Creates a listen socket.

This function is used by the server to create a listening socket. Any MiniGUI-Processes application can call this function to create a listening socket. The server, i.e. mginit, of MiniGUI-Processes uses this function to create its listening socket, and named the socket to '/var/tmp/minigui'.

Parameters

name	The path name of the listening socket.

Returns

The file discriptor of the listening socket created, -1 on error.

Note

As a convention, you should located the socket in '/var/tmp/' directory.

sock_read_t()

ssize_t sock_read_t	(	int	fd,
		void *	buff,
		size_t	count,
		DWORD	timeout
	)

Reads data from socket.

This function reads data which is count bytes long to the buffer buff from the socket fd.

Parameters

fd	The file descriptor of the socket.
buff	The buffer used to save the data.
count	The length in bytes of the buffer.
timeout	An upper bound on the amount of time elapsed before sock_read_t returns. When it is zero, sock_read_t can block indefinitely. The timeout value is in the tick count of MiniGUI, and tick count of MiniGUI is in unit of 10 milliseconds.

Returns

SOCKERR_OK if all OK, < 0 on error.

Return values

SOCKERR_OK	Read data successfully.
SOCKERR_IO	There are some I/O errors occurred.
SOCKERR_CLOSED	The socket has been closed by the peer.
SOCKERR_INVARG	You passed invalid arguments.
SOCKERR_TIMEOUT	Timeout.

Note

The timeout only goes into effect when this function called by the server of MiniGUI-Processes, i.e. mginit.

See also

sock_write_t