iofunc_mmap_default(), iofunc_mmap_default_ext()

Updated: October 26, 2022

Default handler for _IO_MMAP messages

Synopsis:

#include <sys/iofunc.h>

int iofunc_mmap_default ( resmgr_context_t * ctp,
                          io_mmap_t * msg,
                          iofunc_ocb_t * ocb );

int iofunc_mmap_default_ext( resmgr_context_t * const ctp,
                             io_mmap_t * const msg,
                             iofunc_ocb_t * const ocb );

Arguments:

ctp
A pointer to a resmgr_context_t structure that the resource-manager library uses to pass context information between functions.
msg
A pointer to the io_mmap_t structure that contains the message that the resource manager received. For more information, see the documentation for iofunc_mmap().
ocb
A pointer to the iofunc_ocb_t structure for the Open Control Block that was created when the client opened the resource.

Library:

libc

Use the -l c option to qcc to link against this library. This library is usually included automatically.

Description:

The iofunc_mmap_default() and iofunc_mmap_default_ext() functions provide functionality for the _IO_MMAP message. This message is private to the memory manager (a part of the microkernel's procnto).

(QNX Neutrino 7.1 or later) The iofunc_mmap_default_ext() function is an extended version of iofunc_mmap_default() that can return extra information to the memory manager. If called on a device that's mounted, it also fills in the stat information and uses _IO_MMAP_REPLY_FLAGS_STAT_FORM_FLAGS(_STAT_FORM_PREFERRED) to set the flags that it passes to iofunc_mmap_ext().

You can place one of these functions directly into the resmgr_io_funcs_t table passed as the io_funcs argument to resmgr_attach(), at the mmap position, or you can call iofunc_func_init() to initialize all of the functions to their default values.

Note: The default is iofunc_mmap_default().

The iofunc_mmap_default() function calls iofunc_mmap() to do the actual work; iofunc_mmap_default_ext() calls iofunc_mmap_ext().

Note that if you write your own handler for _IO_MMAP messages, and you want the process manager to be able to execute binaries from the resource, then your handler must use the iofunc_mmap() or iofunc_mmap_ext() function.

Returns:

A nonpositive value (i.e., less than or equal to 0)
Successful completion.
EROFS
An attempt to memory map (mmap) a read-only file, using the PROT_WRITE page protection mode.
EACCES
The client doesn't have the appropriate permissions.
ENOMEM
Insufficient memory exists to allocate internal resources required to effect the mapping.

Classification:

QNX Neutrino

Safety:  
Cancellation point No
Interrupt handler No
Signal handler Yes
Thread Yes