forked from mkottman/acpi_call
-
Notifications
You must be signed in to change notification settings - Fork 1
/
acpi_call.c
391 lines (332 loc) · 11.7 KB
/
acpi_call.c
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
/* Copyright (c) 2010: Michal Kottman */
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/version.h>
#include <linux/proc_fs.h>
#include <linux/slab.h>
#include <asm/uaccess.h>
#include <acpi/acpi.h>
MODULE_LICENSE("GPL");
/* Uncomment the following line to enable debug messages */
/*
#define DEBUG
*/
#define BUFFER_SIZE 256
#define MAX_ACPI_ARGS 16
#if LINUX_VERSION_CODE >= KERNEL_VERSION(3, 10, 0)
#define HAVE_PROC_CREATE
#endif
extern struct proc_dir_entry *acpi_root_dir;
static char result_buffer[BUFFER_SIZE];
static u8 temporary_buffer[BUFFER_SIZE];
static size_t get_avail_bytes(void) {
return BUFFER_SIZE - strlen(result_buffer);
}
static char *get_buffer_end(void) {
return result_buffer + strlen(result_buffer);
}
/** Appends the contents of an acpi_object to the result buffer
@param result An acpi object holding result data
@returns 0 if the result could fully be saved, a higher value otherwise
*/
static int acpi_result_to_string(union acpi_object *result) {
if (result->type == ACPI_TYPE_INTEGER) {
snprintf(get_buffer_end(), get_avail_bytes(),
"0x%x", (int)result->integer.value);
} else if (result->type == ACPI_TYPE_STRING) {
snprintf(get_buffer_end(), get_avail_bytes(),
"\"%*s\"", result->string.length, result->string.pointer);
} else if (result->type == ACPI_TYPE_BUFFER) {
int i;
// do not store more than data if it does not fit. The first element is
// just 4 chars, but there is also two bytes from the curly brackets
int show_values = min((size_t)result->buffer.length, get_avail_bytes() / 6);
sprintf(get_buffer_end(), "{");
for (i = 0; i < show_values; i++)
sprintf(get_buffer_end(),
i == 0 ? "0x%02x" : ", 0x%02x", result->buffer.pointer[i]);
if (result->buffer.length > show_values) {
// if data was truncated, show a trailing comma if there is space
snprintf(get_buffer_end(), get_avail_bytes(), ",");
return 1;
} else {
// in case show_values == 0, but the buffer is too small to hold
// more values (i.e. the buffer cannot have anything more than "{")
snprintf(get_buffer_end(), get_avail_bytes(), "}");
}
} else if (result->type == ACPI_TYPE_PACKAGE) {
int i;
sprintf(get_buffer_end(), "[");
for (i=0; i<result->package.count; i++) {
if (i > 0)
snprintf(get_buffer_end(), get_avail_bytes(), ", ");
// abort if there is no more space available
if (!get_avail_bytes() || acpi_result_to_string(&result->package.elements[i]))
return 1;
}
snprintf(get_buffer_end(), get_avail_bytes(), "]");
} else {
snprintf(get_buffer_end(), get_avail_bytes(),
"Object type 0x%x\n", result->type);
}
// return 0 if there are still bytes available, 1 otherwise
return !get_avail_bytes();
}
/**
@param method The full name of ACPI method to call
@param argc The number of parameters
@param argv A pre-allocated array of arguments of type acpi_object
*/
static void do_acpi_call(const char * method, int argc, union acpi_object *argv)
{
acpi_status status;
acpi_handle handle;
struct acpi_object_list arg;
struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
#ifdef DEBUG
printk(KERN_INFO "acpi_call: Calling %s\n", method);
#endif
// get the handle of the method, must be a fully qualified path
status = acpi_get_handle(NULL, (acpi_string) method, &handle);
if (ACPI_FAILURE(status))
{
snprintf(result_buffer, BUFFER_SIZE, "Error: %s", acpi_format_exception(status));
printk(KERN_ERR "acpi_call: Cannot get handle: %s\n", result_buffer);
return;
}
// prepare parameters
arg.count = argc;
arg.pointer = argv;
// call the method
status = acpi_evaluate_object(handle, NULL, &arg, &buffer);
if (ACPI_FAILURE(status))
{
snprintf(result_buffer, BUFFER_SIZE, "Error: %s", acpi_format_exception(status));
printk(KERN_ERR "acpi_call: Method call failed: %s\n", result_buffer);
return;
}
// reset the result buffer
*result_buffer = '\0';
acpi_result_to_string(buffer.pointer);
kfree(buffer.pointer);
#ifdef DEBUG
printk(KERN_INFO "acpi_call: Call successful: %s\n", result_buffer);
#endif
}
/** Decodes 2 hex characters to an u8 int
*/
u8 decodeHex(char *hex) {
char buf[3] = { hex[0], hex[1], 0};
return (u8) simple_strtoul(buf, NULL, 16);
}
/** Parses method name and arguments
@param input Input string to be parsed. Modified in the process.
@param nargs Set to number of arguments parsed (output)
@param args
*/
static char *parse_acpi_args(char *input, int *nargs, union acpi_object **args)
{
char *s = input;
*nargs = 0;
*args = NULL;
// the method name is separated from the arguments by a space
while (*s && *s != ' ')
s++;
// if no space is found, return 0 arguments
if (*s == 0)
return input;
*args = (union acpi_object *) kmalloc(MAX_ACPI_ARGS * sizeof(union acpi_object), GFP_KERNEL);
while (*s) {
if (*s == ' ') {
if (*nargs == 0)
*s = 0; // change first space to nul
++ *nargs;
++ s;
} else {
union acpi_object *arg = (*args) + (*nargs - 1);
if (*s == '"') {
// decode string
arg->type = ACPI_TYPE_STRING;
arg->string.pointer = ++s;
arg->string.length = 0;
while (*s && *s++ != '"')
arg->string.length ++;
// skip the last "
++s;
} else if (*s == 'b') {
// decode buffer - bXXXX
char *p = ++s;
int len = 0, i;
u8 *buf = NULL;
while (*p && *p!=' ')
p++;
len = p - s;
if (len % 2 == 1) {
printk(KERN_ERR "acpi_call: buffer arg%d is not multiple of 8 bits\n", *nargs);
return NULL;
}
len /= 2;
buf = (u8*) kmalloc(len, GFP_KERNEL);
for (i=0; i<len; i++) {
buf[i] = decodeHex(s + i*2);
}
s = p;
arg->type = ACPI_TYPE_BUFFER;
arg->buffer.pointer = buf;
arg->buffer.length = len;
} else if (*s == '{') {
// decode buffer - { b1, b2 ...}
u8 *buf = temporary_buffer;
arg->type = ACPI_TYPE_BUFFER;
arg->buffer.pointer = buf;
arg->buffer.length = 0;
while (*s && *s++ != '}') {
if (buf >= temporary_buffer + sizeof(temporary_buffer)) {
printk(KERN_ERR "acpi_call: buffer arg%d is truncated because the buffer is full\n", *nargs);
// clear remaining arguments
while (*s && *s != '}')
++s;
break;
}
else if (*s >= '0' && *s <= '9') {
// decode integer into buffer
arg->buffer.length ++;
if (s[0] == '0' && s[1] == 'x')
*buf++ = simple_strtol(s+2, 0, 16);
else
*buf++ = simple_strtol(s, 0, 10);
}
// skip until space or comma or '}'
while (*s && *s != ' ' && *s != ',' && *s != '}')
++s;
}
// store the result in new allocated buffer
buf = (u8*) kmalloc(arg->buffer.length, GFP_KERNEL);
memcpy(buf, temporary_buffer, arg->buffer.length);
arg->buffer.pointer = buf;
} else {
// decode integer, N or 0xN
arg->type = ACPI_TYPE_INTEGER;
if (s[0] == '0' && s[1] == 'x') {
arg->integer.value = simple_strtol(s+2, 0, 16);
} else {
arg->integer.value = simple_strtol(s, 0, 10);
}
while (*s && *s != ' ') {
++s;
}
}
}
}
return input;
}
/** procfs write callback. Called when writing into /proc/acpi/call.
*/
#ifdef HAVE_PROC_CREATE
static ssize_t acpi_proc_write( struct file *filp, const char __user *buff,
size_t len, loff_t *data )
#else
static int acpi_proc_write( struct file *filp, const char __user *buff,
unsigned long len, void *data )
#endif
{
char input[2 * BUFFER_SIZE] = { '\0' };
union acpi_object *args;
int nargs, i;
char *method;
if (len > sizeof(input) - 1) {
printk(KERN_ERR "acpi_call: Input too long! (%lu)\n", len);
return -ENOSPC;
}
if (copy_from_user( input, buff, len )) {
return -EFAULT;
}
input[len] = '\0';
if (input[len-1] == '\n')
input[len-1] = '\0';
method = parse_acpi_args(input, &nargs, &args);
if (method) {
do_acpi_call(method, nargs, args);
if (args) {
for (i=0; i<nargs; i++)
if (args[i].type == ACPI_TYPE_BUFFER)
kfree(args[i].buffer.pointer);
kfree(args);
}
}
return len;
}
/** procfs 'call' read callback. Called when reading the content of /proc/acpi/call.
Returns the last call status:
- "not called" when no call was previously issued
- "failed" if the call failed
- "ok" if the call succeeded
*/
#ifdef HAVE_PROC_CREATE
static ssize_t acpi_proc_read( struct file *filp, char __user *buff,
size_t count, loff_t *off )
{
ssize_t ret;
int len = strlen(result_buffer);
// output the current result buffer
ret = simple_read_from_buffer(buff, count, off, result_buffer, len + 1);
// initialize the result buffer for later
strcpy(result_buffer, "not called");
return ret;
}
static struct file_operations proc_acpi_operations = {
.owner = THIS_MODULE,
.read = acpi_proc_read,
.write = acpi_proc_write,
};
#else
static int acpi_proc_read(char *page, char **start, off_t off,
int count, int *eof, void *data)
{
int len = 0;
if (off > 0) {
*eof = 1;
return 0;
}
// output the current result buffer
len = strlen(result_buffer);
memcpy(page, result_buffer, len + 1);
// initialize the result buffer for later
strcpy(result_buffer, "not called");
return len;
}
#endif
/** module initialization function */
static int __init init_acpi_call(void)
{
#ifdef HAVE_PROC_CREATE
struct proc_dir_entry *acpi_entry = proc_create("call",
0660,
acpi_root_dir,
&proc_acpi_operations);
#else
struct proc_dir_entry *acpi_entry = create_proc_entry("call", 0660, acpi_root_dir);
#endif
strcpy(result_buffer, "not called");
if (acpi_entry == NULL) {
printk(KERN_ERR "acpi_call: Couldn't create proc entry\n");
return -ENOMEM;
}
#ifndef HAVE_PROC_CREATE
acpi_entry->write_proc = acpi_proc_write;
acpi_entry->read_proc = acpi_proc_read;
#endif
#ifdef DEBUG
printk(KERN_INFO "acpi_call: Module loaded successfully\n");
#endif
return 0;
}
static void __exit unload_acpi_call(void)
{
remove_proc_entry("call", acpi_root_dir);
#ifdef DEBUG
printk(KERN_INFO "acpi_call: Module unloaded successfully\n");
#endif
}
module_init(init_acpi_call);
module_exit(unload_acpi_call);