summaryrefslogtreecommitdiff
path: root/libsysfs/sysfs_dir.c
blob: 63eec7bb9ac06aa0e042d2a2cc530da636cfb294 (plain)
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
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
/*
 * sysfs_dir.c
 *
 * Directory utility functions for libsysfs
 *
 * Copyright (C) IBM Corp. 2003-2005
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
 *  License as published by the Free Software Foundation; either
 *  version 2.1 of the License, or (at your option) any later version.
 *
 *  This library is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 *  Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this library; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 *
 */
#include "libsysfs.h"
#include "sysfs.h"

static int sort_char(void *new, void *old)
{
	return ((strncmp((char *)new, (char *)old, 
			strlen((char *)new))) < 0 ? 1 : 0);
}

/**
 * sysfs_del_name: free function for sysfs_open_subsystem_list
 * @name: memory area to be freed
 */
static void sysfs_del_name(void *name)
{
	free(name);
}

/**
 * sysfs_del_attribute: routine for dlist integration
 */
static void sysfs_del_attribute(void *attr)
{
	sysfs_close_attribute((struct sysfs_attribute *)attr);
}

/**
 * attr_name_equal: compares attributes by name
 * @a: attribute name for comparison
 * @b: sysfs_attribute to be compared.
 * returns 1 if a==b->name or 0 if not equal
 */
static int attr_name_equal(void *a, void *b)
{
	if (!a || !b)
		return 0;

	if (strcmp(((char *)a), ((struct sysfs_attribute *)b)->name) == 0)
		return 1;

	return 0;
}

/**
 * sysfs_close_attribute: closes and cleans up attribute
 * @sysattr: attribute to close.
 */
void sysfs_close_attribute(struct sysfs_attribute *sysattr)
{
	if (sysattr) {
		if (sysattr->value)
			free(sysattr->value);
		free(sysattr);
	}
}

/**
 * alloc_attribute: allocates and initializes attribute structure
 * returns struct sysfs_attribute with success and NULL with error.
 */
static struct sysfs_attribute *alloc_attribute(void)
{
	return (struct sysfs_attribute *)
			calloc(1, sizeof(struct sysfs_attribute));
}

/**
 * sysfs_open_attribute: creates sysfs_attribute structure
 * @path: path to attribute.
 * returns sysfs_attribute struct with success and NULL with error.
 */
struct sysfs_attribute *sysfs_open_attribute(const char *path)
{
	struct sysfs_attribute *sysattr = NULL;
	struct stat fileinfo;

	if (!path) {
		errno = EINVAL;
		return NULL;
	}
	sysattr = alloc_attribute();
	if (!sysattr) {
		dprintf("Error allocating attribute at %s\n", path);
		return NULL;
	}
	if (sysfs_get_name_from_path(path, sysattr->name, 
				SYSFS_NAME_LEN) != 0) {
		dprintf("Error retrieving attrib name from path: %s\n", path);
		sysfs_close_attribute(sysattr);
		return NULL;
	}
	safestrcpy(sysattr->path, path);
	if ((stat(sysattr->path, &fileinfo)) != 0) {
		dprintf("Stat failed: No such attribute?\n");
		sysattr->method = 0;
		free(sysattr);
		sysattr = NULL;
	} else {
		if (fileinfo.st_mode & S_IRUSR)
			sysattr->method |= SYSFS_METHOD_SHOW;
		if (fileinfo.st_mode & S_IWUSR)
			sysattr->method |= SYSFS_METHOD_STORE;
	}

	return sysattr;
}

/**
 * sysfs_read_attribute: reads value from attribute
 * @sysattr: attribute to read
 * returns 0 with success and -1 with error.
 */
int sysfs_read_attribute(struct sysfs_attribute *sysattr)
{
	char *fbuf = NULL;
	char *vbuf = NULL;
	ssize_t length = 0;
	long pgsize = 0;
	int fd;

	if (!sysattr) {
		errno = EINVAL;
		return -1;
	}
	if (!(sysattr->method & SYSFS_METHOD_SHOW)) {
		dprintf("Show method not supported for attribute %s\n",
			sysattr->path);
		errno = EACCES;
		return -1;
	}
	pgsize = getpagesize();
	fbuf = (char *)calloc(1, pgsize+1);
	if (!fbuf) {
		dprintf("calloc failed\n");
		return -1;
	}
	if ((fd = open(sysattr->path, O_RDONLY)) < 0) {
		dprintf("Error reading attribute %s\n", sysattr->path);
		free(fbuf);
		return -1;
	}
	length = read(fd, fbuf, pgsize);
	if (length < 0) {
		dprintf("Error reading from attribute %s\n", sysattr->path);
		close(fd);
		free(fbuf);
		return -1;
	}
	if (sysattr->len > 0) {
		if ((sysattr->len == length) && 
				(!(strncmp(sysattr->value, fbuf, length)))) {
			close(fd);
			free(fbuf);
			return 0;
		}
		free(sysattr->value);
	}
	sysattr->len = length;
	close(fd);
	vbuf = (char *)realloc(fbuf, length+1);
	if (!vbuf) {
		dprintf("realloc failed\n");
		free(fbuf);
		return -1;
	}
	sysattr->value = vbuf;

	return 0;
}

/**
 * sysfs_write_attribute: write value to the attribute
 * @sysattr: attribute to write
 * @new_value: value to write
 * @len: length of "new_value"
 * returns 0 with success and -1 with error.
 */
int sysfs_write_attribute(struct sysfs_attribute *sysattr,
		const char *new_value, size_t len)
{
	int fd;
	int length;

	if (!sysattr || !new_value || len == 0) {
		errno = EINVAL;
		return -1;
	}

	if (!(sysattr->method & SYSFS_METHOD_STORE)) {
		dprintf ("Store method not supported for attribute %s\n",
			sysattr->path);
		errno = EACCES;
		return -1;
	}
	if (sysattr->method & SYSFS_METHOD_SHOW) {
		/*
		 * read attribute again to see if we can get an updated value 
		 */
		if ((sysfs_read_attribute(sysattr))) {
			dprintf("Error reading attribute\n");
			return -1;
		}
		if ((strncmp(sysattr->value, new_value, sysattr->len)) == 0) {
			dprintf("Attr %s already has the requested value %s\n",
					sysattr->name, new_value);
			return 0;	
		}
	}
	/*
	 * open O_WRONLY since some attributes have no "read" but only
	 * "write" permission 
	 */
	if ((fd = open(sysattr->path, O_WRONLY)) < 0) {
		dprintf("Error reading attribute %s\n", sysattr->path);
		return -1;
	}

	length = write(fd, new_value, len);
	if (length < 0) {
		dprintf("Error writing to the attribute %s - invalid value?\n",
			sysattr->name);
		close(fd);
		return -1;
	} else if ((unsigned int)length != len) {
		dprintf("Could not write %d bytes to attribute %s\n", 
					len, sysattr->name);
		/* 
		 * since we could not write user supplied number of bytes,
		 * restore the old value if one available
		 */
		if (sysattr->method & SYSFS_METHOD_SHOW) {
			length = write(fd, sysattr->value, sysattr->len);
			close(fd);
			return -1;
		}
	}

	/*
	 * Validate length that has been copied. Alloc appropriate area
	 * in sysfs_attribute. Verify first if the attribute supports reading
	 * (show method). If it does not, do not bother
	 */ 
	if (sysattr->method & SYSFS_METHOD_SHOW) {
		if (length != sysattr->len) {
			sysattr->value = (char *)realloc
				(sysattr->value, length);
			sysattr->len = length;
			safestrcpymax(sysattr->value, new_value, length);
		} else {
			/*"length" of the new value is same as old one */ 
			safestrcpymax(sysattr->value, new_value, length);
		}
	}
			
	close(fd);	
	return 0;
}

/**
 * add_attribute: open and add attribute at path to given directory
 * @dev: device whose attribute is to be added
 * @path: path to attribute
 * returns pointer to attr added with success and NULL with error.
 */
static struct sysfs_attribute *add_attribute(void *dev, const char *path)
{
	struct sysfs_attribute *attr;

	attr = sysfs_open_attribute(path);
	if (!attr) {
		dprintf("Error opening attribute %s\n",	path);
		return NULL;
	}
	if (attr->method & SYSFS_METHOD_SHOW) {
		if (sysfs_read_attribute(attr)) {
			dprintf("Error reading attribute %s\n",	path);
			sysfs_close_attribute(attr);
			return NULL;
		}
	}

	if (!((struct sysfs_device *)dev)->attrlist) {
		((struct sysfs_device *)dev)->attrlist = dlist_new_with_delete
			(sizeof(struct sysfs_attribute), sysfs_del_attribute);
	}
	dlist_unshift_sorted(((struct sysfs_device *)dev)->attrlist, 
			attr, sort_list);

	return attr;
}

/*
 * get_attribute - given a sysfs_* struct and a name, return the 
 * sysfs_attribute corresponding to "name"
 * returns sysfs_attribute on success and NULL on error
 */
struct sysfs_attribute *get_attribute(void *dev, const char *name)
{
	struct sysfs_attribute *cur = NULL;
	char path[SYSFS_PATH_MAX];

	if (!dev || !name) {
		errno = EINVAL;
		return NULL;
	}

	if (((struct sysfs_device *)dev)->attrlist) {
		/* check if attr is already in the list */
		cur = (struct sysfs_attribute *)dlist_find_custom
			((((struct sysfs_device *)dev)->attrlist), 
			 	(void *)name, attr_name_equal);
		if (cur)
			return cur;
	}
	safestrcpymax(path, ((struct sysfs_device *)dev)->path, 
			SYSFS_PATH_MAX);
	safestrcatmax(path, "/", SYSFS_PATH_MAX);
	safestrcatmax(path, name, SYSFS_PATH_MAX);
	if (!(sysfs_path_is_file(path)))
		cur = add_attribute((void *)dev, path);
	return cur;
}

/**
 * read_dir_links: grabs links in a specific directory
 * @sysdir: sysfs directory to read
 * returns list of link names with success and NULL with error.
 */
struct dlist *read_dir_links(const char *path)
{
	DIR *dir = NULL;
	struct dirent *dirent = NULL;
	char file_path[SYSFS_PATH_MAX], *linkname;
	struct dlist *linklist = NULL;

	if (!path) {
		errno = EINVAL;
		return NULL;
	}
	dir = opendir(path);
	if (!dir) {
		dprintf("Error opening directory %s\n", path);
		return NULL;
	}
	while ((dirent = readdir(dir)) != NULL) {
		if (0 == strcmp(dirent->d_name, "."))
			 continue;
		if (0 == strcmp(dirent->d_name, ".."))
			continue;
		memset(file_path, 0, SYSFS_PATH_MAX);
		safestrcpy(file_path, path);
		safestrcat(file_path, "/");
		safestrcat(file_path, dirent->d_name);
		if ((sysfs_path_is_link(file_path)) == 0) {
			if (!linklist) {
				linklist = dlist_new_with_delete
					(SYSFS_NAME_LEN, sysfs_del_name);
				if (!linklist) {
					dprintf("Error creating list\n");
					return NULL;
				}
			}
			linkname = (char *)calloc(1, SYSFS_NAME_LEN);
			safestrcpymax(linkname, dirent->d_name, SYSFS_NAME_LEN);
			dlist_unshift_sorted(linklist, linkname, sort_char);
		}
	}
	closedir(dir);
	return linklist;
}

/**
 * read_dir_subdirs: grabs subdirs in a specific directory
 * @sysdir: sysfs directory to read
 * returns list of directory names with success and NULL with error.
 */
struct dlist *read_dir_subdirs(const char *path)
{
	DIR *dir = NULL;
	struct dirent *dirent = NULL;
	char file_path[SYSFS_PATH_MAX], *dir_name;
	struct dlist *dirlist = NULL;

	if (!path) {
		errno = EINVAL;
		return NULL;
	}
	dir = opendir(path);
	if (!dir) {
		dprintf("Error opening directory %s\n", path);
		return NULL;
	}
	while ((dirent = readdir(dir)) != NULL) {
		if (0 == strcmp(dirent->d_name, "."))
			 continue;
		if (0 == strcmp(dirent->d_name, ".."))
			continue;
		memset(file_path, 0, SYSFS_PATH_MAX);
		safestrcpy(file_path, path);
		safestrcat(file_path, "/");
		safestrcat(file_path, dirent->d_name);
		if ((sysfs_path_is_dir(file_path)) == 0) {
			if (!dirlist) {
				dirlist = dlist_new_with_delete
					(SYSFS_NAME_LEN, sysfs_del_name);
				if (!dirlist) {
					dprintf("Error creating list\n");
					return NULL;
				}
			}
			dir_name = (char *)calloc(1, SYSFS_NAME_LEN);
			safestrcpymax(dir_name, dirent->d_name, SYSFS_NAME_LEN);
			dlist_unshift_sorted(dirlist, dir_name, sort_char);
		}
	}
	closedir(dir);
	return dirlist;
}

/**
 * get_attributes_list: build a list of attributes for the given device
 * @dev: devices whose attributes list is required
 * returns dlist of attributes on success and NULL on failure
 */
struct dlist *get_attributes_list(void *dev)
{
	DIR *dir = NULL;
	struct dirent *dirent = NULL;
	struct sysfs_attribute *attr = NULL;
	char file_path[SYSFS_PATH_MAX], path[SYSFS_PATH_MAX];

	if (!dev) {
		errno = EINVAL;
		return NULL;
	}
	memset(path, 0, SYSFS_PATH_MAX);
	safestrcpy(path, ((struct sysfs_device *)dev)->path);
	dir = opendir(path);
	if (!dir) {
		dprintf("Error opening directory %s\n", path);
		return NULL;
	}
	while ((dirent = readdir(dir)) != NULL) {
		if (0 == strcmp(dirent->d_name, "."))
			 continue;
		if (0 == strcmp(dirent->d_name, ".."))
			continue;
		memset(file_path, 0, SYSFS_PATH_MAX);
		safestrcpy(file_path, path);
		safestrcat(file_path, "/");
		safestrcat(file_path, dirent->d_name);
		if ((sysfs_path_is_file(file_path)) == 0) {
			if (((struct sysfs_device *)dev)->attrlist) {
				/* check if attr is already in the list */
				attr = (struct sysfs_attribute *)
				dlist_find_custom
				((((struct sysfs_device *)dev)->attrlist), 
			 	(void *)dirent->d_name, attr_name_equal);
				if (attr) 
					continue;
				else 
					add_attribute(dev, file_path);
			} else 
				attr = add_attribute(dev, file_path);
		}
	}
	closedir(dir);
	return ((struct sysfs_device *)dev)->attrlist;
}