Getting Started with QNX Neutrino - QNX Software Systems

Alphabetical listing of connect and I/O functions
© 2009, QNX Software Systems GmbH & Co. KG.
pathnames; the “original” pathname and the “new” pathname. The original pathname
is passed in path, because it’s the thing being worked on (it’s the filename that’s
undergoing the name change). The new pathname is the argument to the operation.
You’ll see that the extra parameter passed to the connect functions conveniently
contains a pointer to the argument of the operation — in this case, the new pathname.
(Implementation-wise, the new pathname is stored just past the original pathname in
the path pointer, with alignment taken into consideration, but you don’t have to do
anything about this — the extra parameter conveniently gives you the correct pointer.)
Alphabetical listing of connect and I/O functions
This section gives an alphabetical listing of the connect and I/O function entry points
that you can fill in (the two tables passed to resmgr_attach()). Remember that if you
simply call iofunc_func_init(), all these entries will be filled in with the appropriate
defaults; you’d want to modify a particular entry only if you wish to handle that
particular message. In the “Examples” section, below, you’ll see some examples of the
common functions.
It may seem confusing at first, but note that there are in fact two unblock outcalls —
one is a connect function and one is an I/O function. This is correct; it’s a reflection of
when the unblock occurs. The connect version of the unblock function is used when
the kernel unblocks the client immediately after the client has sent the connect
message; the I/O version of the unblock function is used when the kernel unblocks the
client immediately after the client has sent an I/O message.
In order not to confuse the client’s C-library call (for example, open()) with the
resource manager connect outcall that goes into that particular slot, we’ve given all of
our functions an “io_” prefix. For example, the function description for the open
connect outcall slot will be under io_open().
io_chmod()
int io_chmod (resmgr_context_t *ctp, io_chmod_t *msg,
RESMGR_OCB_T *ocb)
Classification: I/O function
Default handler: iofunc_chmod_default()
Helper functions: iofunc_chmod()
Client functions: chmod(), fchmod()
Messages: _IO_CHMOD
Data structure:
struct _io_chmod {
uint16_t type;
uint16_t combine_len;
mode_t mode;
};
230 Chapter 5 • Resource Managers April 30, 2009