1 #include <minix/drivers.h>
2 #include <minix/chardriver.h>
3 #include <stdio.h>
4 #include <stdlib.h>
5 #include <minix/ds.h>
6 #include "hello.h"
7
8 /*
9 * Function prototypes for the hello driver.
10 */
11 static int hello_open(devminor_t minor, int access, endpoint_t user_endpt);
12 static int hello_close(devminor_t minor);
13 static ssize_t hello_read(devminor_t minor, u64_t position, endpoint_t endpt,
14 cp_grant_id_t grant, size_t size, int flags, cdev_id_t id);
15
16 /* SEF functions and variables. */
17 static void sef_local_startup(void);
18 static int sef_cb_init(int type, sef_init_info_t *info);
19 static int sef_cb_lu_state_save(int, int);
20 static int lu_state_restore(void);
21
22 /* Entry points to the hello driver. */
23 static struct chardriver hello_tab =
24 {
25 .cdr_open = hello_open,
26 .cdr_close = hello_close,
27 .cdr_read = hello_read,
28 };
29
30 /** State variable to count the number of times the device has been opened.
31 * Note that this is not the regular type of open counter: it never decreases.
32 */
33 static int open_counter;
34
hello_open(devminor_t UNUSED (minor),int UNUSED (access),endpoint_t UNUSED (user_endpt))35 static int hello_open(devminor_t UNUSED(minor), int UNUSED(access),
36 endpoint_t UNUSED(user_endpt))
37 {
38 printf("hello_open(). Called %d time(s).\n", ++open_counter);
39 return OK;
40 }
41
hello_close(devminor_t UNUSED (minor))42 static int hello_close(devminor_t UNUSED(minor))
43 {
44 printf("hello_close()\n");
45 return OK;
46 }
47
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))48 static ssize_t hello_read(devminor_t UNUSED(minor), u64_t position,
49 endpoint_t endpt, cp_grant_id_t grant, size_t size, int UNUSED(flags),
50 cdev_id_t UNUSED(id))
51 {
52 u64_t dev_size;
53 char *ptr;
54 int ret;
55 char *buf = HELLO_MESSAGE;
56
57 printf("hello_read()\n");
58
59 /* This is the total size of our device. */
60 dev_size = (u64_t) strlen(buf);
61
62 /* Check for EOF, and possibly limit the read size. */
63 if (position >= dev_size) return 0; /* EOF */
64 if (position + size > dev_size)
65 size = (size_t)(dev_size - position); /* limit size */
66
67 /* Copy the requested part to the caller. */
68 ptr = buf + (size_t)position;
69 if ((ret = sys_safecopyto(endpt, grant, 0, (vir_bytes) ptr, size)) != OK)
70 return ret;
71
72 /* Return the number of bytes read. */
73 return size;
74 }
75
sef_cb_lu_state_save(int UNUSED (state),int UNUSED (flags))76 static int sef_cb_lu_state_save(int UNUSED(state), int UNUSED(flags)) {
77 /* Save the state. */
78 ds_publish_u32("open_counter", open_counter, DSF_OVERWRITE);
79
80 return OK;
81 }
82
lu_state_restore()83 static int lu_state_restore() {
84 /* Restore the state. */
85 u32_t value;
86
87 ds_retrieve_u32("open_counter", &value);
88 ds_delete_u32("open_counter");
89 open_counter = (int) value;
90
91 return OK;
92 }
93
sef_local_startup()94 static void sef_local_startup()
95 {
96 /*
97 * Register init callbacks. Use the same function for all event types
98 */
99 sef_setcb_init_fresh(sef_cb_init);
100 sef_setcb_init_lu(sef_cb_init);
101 sef_setcb_init_restart(sef_cb_init);
102
103 /*
104 * Register live update callbacks.
105 */
106 sef_setcb_lu_state_save(sef_cb_lu_state_save);
107
108 /* Let SEF perform startup. */
109 sef_startup();
110 }
111
sef_cb_init(int type,sef_init_info_t * UNUSED (info))112 static int sef_cb_init(int type, sef_init_info_t *UNUSED(info))
113 {
114 /* Initialize the hello driver. */
115 int do_announce_driver = TRUE;
116
117 open_counter = 0;
118 switch(type) {
119 case SEF_INIT_FRESH:
120 printf("%s", HELLO_MESSAGE);
121 break;
122
123 case SEF_INIT_LU:
124 /* Restore the state. */
125 lu_state_restore();
126 do_announce_driver = FALSE;
127
128 printf("%sHey, I'm a new version!\n", HELLO_MESSAGE);
129 break;
130
131 case SEF_INIT_RESTART:
132 printf("%sHey, I've just been restarted!\n", HELLO_MESSAGE);
133 break;
134 }
135
136 /* Announce we are up when necessary. */
137 if (do_announce_driver) {
138 chardriver_announce();
139 }
140
141 /* Initialization completed successfully. */
142 return OK;
143 }
144
main(void)145 int main(void)
146 {
147 /*
148 * Perform initialization.
149 */
150 sef_local_startup();
151
152 /*
153 * Run the main loop.
154 */
155 chardriver_task(&hello_tab);
156 return OK;
157 }
158
159