door_call(3DOOR) Door Library Functions door_call(3DOOR)NAMEdoor_call - invoke the function associated with a door descriptor
SYNOPSIS
cc [ flag... ] file... -ldoor [ library... ]
#include <door.h>
typedef struct {
char *data_ptr; /* Argument/result buf ptr*/
size_t data_size; /* Argument/result buf size */
door_desc_t *desc_ptr; /* Argument/result descriptors */
uint_t desc_num; /* Argument/result num desc */
char *rbuf; /* Result buffer */
size_t rsize; /* Result buffer size */
} door_arg_t;
int door_call(int d, door_arg_t *params);
DESCRIPTION
The door_call() function invokes the function associated with the door
descriptor d, and passes the arguments (if any) specified in params.
All of the params members are treated as in/out parameters during a
door invocation and may be updated upon returning from a door call.
Passing NULL for params indicates there are no arguments to be passed
and no results expected.
Arguments are specified using the data_ptr and desc_ptr members of
params. The size of the argument data in bytes is passed in data_size
and the number of argument descriptors is passed in desc_num.
Results from the door invocation are placed in the buffer, rbuf. See
door_return(3DOOR). The data_ptr and desc_ptr members of params are
updated to reflect the location of the results within the rbuf buffer.
The size of the data results and number of descriptors returned are
updated in the data_size and desc_num members. It is acceptable to use
the same buffer for input argument data and results, so door_call()
may be called with data_ptr and desc_ptr pointing to the buffer rbuf.
If the results of a door invocation exceed the size of the buffer spec‐
ified by rsize, the system automatically allocates a new buffer in the
caller's address space and updates the rbuf and rsize members to
reflect this location. In this case, the caller is responsible for
reclaiming this area using munmap(rbuf, rsize) when the buffer is no
longer required. See munmap(2).
Descriptors passed in a door_desc_t structure are identified by the
d_attributes member. The client marks the d_attributes member with the
type of object being passed by logically OR-ing the value of object
type. Currently, the only object type that can be passed or returned is
a file descriptor, denoted by the DOOR_DESCRIPTOR attribute. Addition‐
ally, the DOOR_RELEASE attribute can be set, causing the descriptor to
be closed in the caller's address space after it is passed to the tar‐
get. The descriptor will be closed even if door_call() returns an
error, unless that error is EFAULT or EBADF.
The door_desc_t structure includes the following members:
typedef struct {
door_attr_t d_attributes; /* Describes the parameter */
union {
struct {
int d_descriptor; /* Descriptor */
door_id_t d_id; /* Unique door id */
} d_desc;
} d_data;
} door_desc_t;
When file descriptors are passed or returned, a new descriptor is cre‐
ated in the target address space and the d_descriptor member in the
target argument is updated to reflect the new descriptor. In addition,
the system passes a system-wide unique number associated with each door
in the door_id member and marks the d_attributes member with other
attributes associated with a door including the following:
DOOR_LOCAL The door received was created by this process
using door_create(). See door_create(3DOOR).
DOOR_PRIVATE The door received has a private pool of server
threads associated with the door.
DOOR_UNREF The door received is expecting an unreferenced
notification.
DOOR_UNREF_MULTI Similar to DOOR_UNREF, except multiple unref‐
erenced notifications may be delivered for the
same door.
DOOR_REFUSE_DESC This door does not accept argument descriptors.
DOOR_REVOKED The door received has been revoked by the
server.
The door_call() function is not a restartable system call. It returns
EINTR if a signal was caught and handled by this thread. If the door
invocation is not idempotent the caller should mask any signals that
may be generated during a door_call() operation. If the client aborts
in the middle of a door_call(), the server thread is notified using the
POSIX (see standards(5)) thread cancellation mechanism. See cancella‐
tion(5).
The descriptor returned from door_create() is marked as close on exec
(FD_CLOEXEC). Information about a door is available for all clients of
a door using door_info(). Applications 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. See door_info(3DOOR).
RETURN VALUES
Upon successful completion, 0 is returned. Otherwise, −1 is returned
and errno is set to indicate the error.
ERRORS
The door_call() function will fail if:
E2BIG Arguments were too big for server thread stack.
EAGAIN Server was out of available resources.
EBADF Invalid door descriptor was passed.
EFAULT Argument pointers pointed outside the allocated address
space.
EINTR A signal was caught in the client, the client called
fork(2), or the server exited during invocation.
EINVAL Bad arguments were passed.
EMFILE The client or server has too many open descriptors.
ENOTSUP The desc_num argument is non-zero and the door has the
DOOR_REFUSE_DESC flag set.
EOVERFLOW System could not create overflow area in caller for
results.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
┌─────────────────────────────┬─────────────────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├─────────────────────────────┼─────────────────────────────┤
│Architecture │all │
├─────────────────────────────┼─────────────────────────────┤
│Availability │SUNWcsu │
├─────────────────────────────┼─────────────────────────────┤
│Interface Stability │Evolving │
├─────────────────────────────┼─────────────────────────────┤
│MT-Level │Safe │
└─────────────────────────────┴─────────────────────────────┘
SEE ALSOmunmap(2), door_create(3DOOR), door_info(3DOOR), door_return(3DOOR),
libdoor(3LIB), attributes(5), cancellation(5), standards(5)SunOS 5.10 14 Feb 2003 door_call(3DOOR)
