_FINI(9E) Driver Entry Points _FINI(9E)

NAME

_fini, _info, _init - loadable module configuration entry points

SYNOPSIS

#include <sys/modctl.h>


int _fini(void)


int _info(struct modinfo *modinfop);


int _init(void)

INTERFACE LEVEL

illumos DDI specific (illumos DDI). These entry points are required. You
must write them.

PARAMETERS

_info()
modinfop
A pointer to an opaque modinfo structure.

DESCRIPTION

_init() initializes a loadable module. It is called before any other
routine in a loadable module. _init() returns the value returned by
mod_install(9F). The module may optionally perform some other work before
the mod_install(9F) call is performed. If the module has done some setup
before the mod_install(9F) function is called, then it should be prepared
to undo that setup if mod_install(9F) returns an error.


_info() returns information about a loadable module. _info() returns the
value returned by mod_info(9F).


_fini() prepares a loadable module for unloading. It is called when the
system wants to unload a module. If the module determines that it can be
unloaded, then _fini() returns the value returned by mod_remove(9F). Upon
successful return from _fini() no other routine in the module will be
called before _init() is called. If _init() did not successfully
complete, _fini() will not be called.

RETURN VALUES

_init() should return the appropriate error number if there is an error,
otherwise it should return the return value from mod_install(9F).


_info() should return the return value from mod_info(9F)


_fini() should return the return value from mod_remove(9F). _fini() is
permitted to return EBUSY prior to calling mod_remove(9F) if the driver
should not be unloaded. Driver global resources, such as mutexes and
calls to ddi_soft_state_fini(9F), should only be destroyed in _fini()
after mod_remove() returns successfully.

EXAMPLES

Example 1: Initializing and Freeing a Mutex

The following example demonstrates how to initialize and free a
mutex(9F).


#include <sys/modctl.h>
#include <sys/ddi.h>
#include <sys/sunddi.h>
static struct dev_ops drv_ops;
/*
* Module linkage information for the kernel.
*/
static struct modldrv modldrv = {
&mod_driverops, /* Type of module. This one is a driver */
"Sample Driver",
&drv_ops /* driver ops */
};

static struct modlinkage modlinkage = {
MODREV_1,
&modldrv,
NULL
};


/*
* Global driver mutex
*/
static kmutex_t xx_global_mutex;


int
_init(void)
{
int i;

/*
* Initialize global mutex before mod_install'ing driver.
* If mod_install() fails, must clean up mutex initialization
*/
mutex_init(&xx_global_mutex, NULL,
MUTEX_DRIVER, (void *)NULL);

if ((i = mod_install(&modlinkage)) != 0) {
mutex_destroy(&xx_global_mutex);
}

return (i);
}

int
_info(struct modinfo *modinfop)
{
return (mod_info(&modlinkage, modinfop));
}


int
_fini(void)
{
int i;

/*
* If mod_remove() is successful, we destroy our global mutex
*/
if ((i = mod_remove(&modlinkage)) == 0) {
mutex_destroy(&xx_global_mutex);
}
return (i);
}

SEE ALSO

add_drv(8), mod_info(9F), mod_install(9F), mod_remove(9F), mutex(9F),
modldrv(9S), modlinkage(9S), modlstrmod(9S)


Writing Device Drivers

WARNINGS

Do not change the structures referred to by the modlinkage structure
after the call to mod_install(), as the system may copy or change them.

NOTES

Even though the identifiers _fini(), _info(), and _init() appear to be
declared as globals, their scope is restricted by the kernel to the
module that they are defined in.

BUGS

On some implementations _info() may be called before _init().


May 6, 2020 _FINI(9E)