| Updated: April 19, 2023 |
Verify a client's ability to open or to create a resource
#include <sys/iofunc.h>
int iofunc_open( resmgr_context_t *ctp,
io_open_t *msg,
iofunc_attr_t *attr,
iofunc_attr_t *dattr,
struct _client_info *info );
libc
Use the -l c option to qcc to link against this library. This library is usually included automatically.
The iofunc_open() function is a helper function for resource managers that implement open(). It checks to see if the client (described by the optional info structure) has access to open the resource identified by attr if dattr is NULL, or it creates a file in the directory identified by dattr if dattr is non-NULL.
In the first case, attr must be non-NULL and point to a structure that describes the resource's attributes.
In the second case, a file is being created in the directory described by the structure that dattr points to. If attr is non-NULL, the attribute structure that it points to gets initialized. If attr is NULL, no initialization is done; only access validation is done.
The info argument can be passed as NULL, in which case iofunc_open() obtains the client information itself via a call to iofunc_client_info_ext(). It is, of course, more efficient to get this information once, rather than calling this function with info set to NULL every time.
The io_open_t structure holds the _IO_CONNECT message received by the resource manager:
typedef union {
struct _io_connect connect;
struct _io_connect_link_reply link_reply;
struct _io_connect_ftype_reply ftype_reply;
} io_open_t;
This message structure is a union of an input message (coming to the resource manager), _io_connect, and two possible output or reply messages (going back to the client):
Or:
| Safety: | |
|---|---|
| Cancellation point | No |
| Interrupt handler | No |
| Signal handler | Yes |
| Thread | Yes |