door_create(3DOOR) Door Library Functions door_create(3DOOR)NAMEdoor_create - create a door descriptor
SYNOPSIS
cc -mt [ flag ... ] file ... -ldoor [ 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 specified 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(3DOOR) invocations. Other arguments passed to server_proce‐
dure 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 unreferenced 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 refer‐
ring to the door drops to one more than once. Since an additional
reference may have been passed by the time an unreferenced invoca‐
tion arrives, the DOOR_IS_UNREF attribute returned by the
door_info(3DOOR) 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(3DOOR). See also door_xcreate(3DOOR) for an alter‐
native means of creating private doors.
DOOR_REFUSE_DESC
Any attempt to door_call(3DOOR) 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.
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(3DOOR). 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.
By default, additional threads are created as needed to handle concur‐
rent door_call(3DOOR) invocations. See door_server_create(3DOOR) for
information on how to change this behavior.
A process can advertise a door in the file system name space using fat‐
tach(3C).
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 namespace.
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 │Evolving │
├─────────────────────────────┼─────────────────────────────┤
│MT-Level │Safe │
└─────────────────────────────┴─────────────────────────────┘
SEE ALSOdoor_bind(3DOOR), door_call(3DOOR), door_info(3DOOR),
door_revoke(3DOOR), door_server_create(3DOOR), door_xcreate(3DOOR),
fattach(3C), libdoor(3LIB), attributes(5)SunOS 5.10 19 Apr 2010 door_create(3DOOR)
