| _FINI(9E) | Driver Entry Points | _FINI(9E) |
_fini, _info, _init - loadable module configuration entry points
#include <sys/modctl.h> int _fini(void)
int _info(struct modinfo *modinfop);
int _init(void)
illumos DDI specific (illumos DDI). These entry points are required. You must write them.
modinfop
_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.
_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.
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); }
add_drv(8), mod_info(9F), mod_install(9F), mod_remove(9F), mutex(9F), modldrv(9S), modlinkage(9S), modlstrmod(9S)
Writing Device Drivers
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.
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.
On some implementations _info() may be called before _init().
| May 6, 2020 | OmniOS |