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#include <minix/drivers.h>
#include <minix/chardriver.h>
#include <stdio.h>
#include <stdlib.h>
#include <minix/ds.h>
#include "hello.h"
/*
* Function prototypes for the hello driver.
*/
static int hello_open(devminor_t minor, int access, endpoint_t user_endpt);
static int hello_close(devminor_t minor);
static ssize_t hello_read(devminor_t minor, u64_t position, endpoint_t endpt,
cp_grant_id_t grant, size_t size, int flags, cdev_id_t id);
/* SEF functions and variables. */
static void sef_local_startup(void);
static int sef_cb_init(int type, sef_init_info_t *info);
static int sef_cb_lu_state_save(int, int);
static int lu_state_restore(void);
/* Entry points to the hello driver. */
static struct chardriver hello_tab =
{
.cdr_open = hello_open,
.cdr_close = hello_close,
.cdr_read = hello_read,
};
/** State variable to count the number of times the device has been opened.
* Note that this is not the regular type of open counter: it never decreases.
*/
static int open_counter;
static int hello_open(devminor_t UNUSED(minor), int UNUSED(access),
endpoint_t UNUSED(user_endpt))
{
printf("hello_open(). Called %d time(s).\n", ++open_counter);
return OK;
}
static int hello_close(devminor_t UNUSED(minor))
{
printf("hello_close()\n");
return OK;
}
static ssize_t hello_read(devminor_t UNUSED(minor), u64_t position,
endpoint_t endpt, cp_grant_id_t grant, size_t size, int UNUSED(flags),
cdev_id_t UNUSED(id))
{
u64_t dev_size;
char *ptr;
int ret;
char *buf = HELLO_MESSAGE;
printf("hello_read()\n");
/* This is the total size of our device. */
dev_size = (u64_t) strlen(buf);
/* Check for EOF, and possibly limit the read size. */
if (position >= dev_size) return 0; /* EOF */
if (position + size > dev_size)
size = (size_t)(dev_size - position); /* limit size */
/* Copy the requested part to the caller. */
ptr = buf + (size_t)position;
if ((ret = sys_safecopyto(endpt, grant, 0, (vir_bytes) ptr, size)) != OK)
return ret;
/* Return the number of bytes read. */
return size;
}
static int sef_cb_lu_state_save(int UNUSED(state), int UNUSED(flags)) {
/* Save the state. */
ds_publish_u32("open_counter", open_counter, DSF_OVERWRITE);
return OK;
}
static int lu_state_restore() {
/* Restore the state. */
u32_t value;
ds_retrieve_u32("open_counter", &value);
ds_delete_u32("open_counter");
open_counter = (int) value;
return OK;
}
static void sef_local_startup()
{
/*
* Register init callbacks. Use the same function for all event types
*/
sef_setcb_init_fresh(sef_cb_init);
sef_setcb_init_lu(sef_cb_init);
sef_setcb_init_restart(sef_cb_init);
/*
* Register live update callbacks.
*/
sef_setcb_lu_state_save(sef_cb_lu_state_save);
/* Let SEF perform startup. */
sef_startup();
}
static int sef_cb_init(int type, sef_init_info_t *UNUSED(info))
{
/* Initialize the hello driver. */
int do_announce_driver = TRUE;
open_counter = 0;
switch(type) {
case SEF_INIT_FRESH:
printf("%s", HELLO_MESSAGE);
break;
case SEF_INIT_LU:
/* Restore the state. */
lu_state_restore();
do_announce_driver = FALSE;
printf("%sHey, I'm a new version!\n", HELLO_MESSAGE);
break;
case SEF_INIT_RESTART:
printf("%sHey, I've just been restarted!\n", HELLO_MESSAGE);
break;
}
/* Announce we are up when necessary. */
if (do_announce_driver) {
chardriver_announce();
}
/* Initialization completed successfully. */
return OK;
}
int main(void)
{
/*
* Perform initialization.
*/
sef_local_startup();
/*
* Run the main loop.
*/
chardriver_task(&hello_tab);
return OK;
}
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