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OpenSolaris 2009.06 - man page for door_create (opensolaris section 3c)

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door_create(3C)  		   Standard C Library Functions 		    door_create(3C) 

NAME
       door_create - create a door descriptor

SYNOPSIS
       cc -mt [ flag... ] file... [ library... ]
       #include <door.h>

       int door_create(void (*server_procedure) (void *cookie, char *argp,
	    size_t arg_size, door_desc_t *dp, uint_t n_desc), void *cookie,
	    uint_t attributes);

DESCRIPTION
       The  door_create()  function creates a door descriptor that describes the procedure speci-
       fied by	the function server_procedure. The data item, cookie, is associated with the door
       descriptor,   and is passed as an argument to the invoked function server_procedure during
         door_call(3C)  invocations.  Other arguments passed to server_procedure from an  associated
       door_call()  are  placed on the stack and include argp and dp. The argp argument points to
       arg_size bytes of data and the dp argument points to n_desc  door_desc_t  structures.  The
       attributes  argument  specifies	attributes  associated with the newly created door. Valid
       values for attributes are constructed by OR-ing one or more of the following values:

       DOOR_UNREF

	   Delivers a special invocation on the door when the number of descriptors that refer to
	   this  door drops to one.  In order to trigger this condition, more than one descriptor
	   must have referred to this door at some time. DOOR_UNREF_DATA designates  an  unrefer-
	   enced  invocation,  as the argp argument passed to server_procedure. In the case of an
	   unreferenced invocation, the values for  arg_size, dp and n_did are 0. Only one unref-
	   erenced invocation is delivered on behalf of a door.

       DOOR_UNREF_MULTI

	   Similar  to	DOOR_UNREF,  except multiple unreferenced invocations can be delivered on
	   the same door if the number of descriptors referring to the door  drops  to	one  more
	   than once.  Since an additional reference may have been passed by the time an unrefer-
	   enced invocation arrives, the DOOR_IS_UNREF attribute returned  by  the    door_info(3C) 
	   call can be used to determine if the door is still unreferenced.

       DOOR_PRIVATE

	   Maintains a separate pool of server threads on behalf  of the door. Server threads are
	   associated with a door's  private server pool using	  door_bind(3C) .

       DOOR_REFUSE_DESC

	   Any attempt to call   door_call(3C)  on this door with	argument  descriptors  will  fail
	   with  ENOTSUP.  When  this  flag  is  set,  the door's server procedure will always be
	   invoked with an n_desc argument of 0.

       DOOR_NO_CANCEL

	   Clients which abort calls to door_call() on this door will not cause the  cancellation
	   of the server thread handling the request.  See   cancellation(5) .

       The  descriptor	returned from door_create() will be marked as close on exec (FD_CLOEXEC).
       Information about a door is available for all clients of a door using door_info().  Appli-
       cations	concerned  with security should not place secure information in door data that is
       accessible by door_info(). In particular, secure data should not be  stored  in	the  data
       item cookie.

       By  default,  additional  threads  are  created as needed to handle concurrent door_call()
       invocations.   See   door_server_create(3C)  for information on how to change this behavior.

       A process can advertise a door in the file system name space using   fattach(3C) .

       After creation,   door_setparam(3C)  can be used to set limits on  the  amount  of	data  and
       descriptors clients can send over the door.

RETURN VALUES
       Upon  successful  completion,  door_create()  returns  a  non-negative  value.  Otherwise,
       door_create returns -1 and sets errno to indicate the error.

ERRORS
       The door_create() function will fail if:

       EINVAL	 Invalid attributes are passed.

       EMFILE	 The process has too many open descriptors.

EXAMPLES
       Example 1 Create a door and use fattach() to advertise the door in the file system  names-
       pace.

       The  following example creates a door and uses fattach() to advertise the door in the file
       system namespace.

	 void
	 server(void *cookie, char *argp, size_t arg_size, door_desc_t *dp,
	     uint_t n_desc)
	 {
	     door_return(NULL, 0, NULL, 0);
	     /* NOTREACHED */
	 }

	 int
	 main(int argc, char *argv[])
	 {
	     int did;
	     struct stat buf;

	     if ((did = door_create(server, 0, 0)) < 0) {
		 perror("door_create");
		   exit(1) ;
	     }

	     /* make sure file system location exists */
	     if (stat("/tmp/door", &buf) < 0) {
		 int newfd;
		 if ((newfd = creat("/tmp/door", 0444)) < 0) {
		     perror("creat");
		       exit(1) ;
		 }
		 (void) close(newfd);
	     }

	     /* make sure nothing else is attached */
	     (void) fdetach("/tmp/door");

	     /* attach to file system */
	     if (fattach(did, "/tmp/door") < 0) {
		 perror("fattach");
		   exit(2) ;
	     }
	     [...]
	 }

ATTRIBUTES
       See   attributes(5)  for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Architecture		     |all			   |
       +-----------------------------+-----------------------------+
       |Availability		     |SUNWcsu			   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |Committed 		   |
       +-----------------------------+-----------------------------+
       |MT-Level		     |Safe			   |
       +-----------------------------+-----------------------------+

SEE ALSO
         door_bind(3C) ,	  door_call(3C) ,	   door_info(3C) ,      door_revoke(3C) ,      door_setparam(3C) ,
         door_server_create(3C) ,   fattach(3C) ,   libdoor(3LIB) ,   attributes(5) ,   cancellation(5) 

SunOS 5.11				   22 Jan 2008				    door_create(3C)
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