xref: /linux/tools/iio/iio_utils.c (revision 79790b6818e96c58fe2bffee1b418c16e64e7b80)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /* IIO - useful set of util functionality
3  *
4  * Copyright (c) 2008 Jonathan Cameron
5  */
6 #include <string.h>
7 #include <stdlib.h>
8 #include <stdio.h>
9 #include <stdint.h>
10 #include <dirent.h>
11 #include <errno.h>
12 #include <ctype.h>
13 #include "iio_utils.h"
14 
15 const char *iio_dir = "/sys/bus/iio/devices/";
16 
17 static char * const iio_direction[] = {
18 	"in",
19 	"out",
20 };
21 
22 /**
23  * iioutils_break_up_name() - extract generic name from full channel name
24  * @full_name: the full channel name
25  * @generic_name: the output generic channel name
26  *
27  * Returns 0 on success, or a negative error code if string extraction failed.
28  **/
iioutils_break_up_name(const char * full_name,char ** generic_name)29 int iioutils_break_up_name(const char *full_name, char **generic_name)
30 {
31 	char *current;
32 	char *w, *r;
33 	char *working, *prefix = "";
34 	int i, ret;
35 
36 	for (i = 0; i < ARRAY_SIZE(iio_direction); i++)
37 		if (!strncmp(full_name, iio_direction[i],
38 			     strlen(iio_direction[i]))) {
39 			prefix = iio_direction[i];
40 			break;
41 		}
42 
43 	current = strdup(full_name + strlen(prefix) + 1);
44 	if (!current)
45 		return -ENOMEM;
46 
47 	working = strtok(current, "_\0");
48 	if (!working) {
49 		free(current);
50 		return -EINVAL;
51 	}
52 
53 	w = working;
54 	r = working;
55 
56 	while (*r != '\0') {
57 		if (!isdigit(*r)) {
58 			*w = *r;
59 			w++;
60 		}
61 
62 		r++;
63 	}
64 	*w = '\0';
65 	ret = asprintf(generic_name, "%s_%s", prefix, working);
66 	free(current);
67 
68 	return (ret == -1) ? -ENOMEM : 0;
69 }
70 
71 /**
72  * iioutils_get_type() - find and process _type attribute data
73  * @is_signed: output whether channel is signed
74  * @bytes: output how many bytes the channel storage occupies
75  * @bits_used: output number of valid bits of data
76  * @shift: output amount of bits to shift right data before applying bit mask
77  * @mask: output a bit mask for the raw data
78  * @be: output if data in big endian
79  * @device_dir: the IIO device directory
80  * @buffer_idx: the IIO buffer index
81  * @name: the channel name
82  * @generic_name: the channel type name
83  *
84  * Returns a value >= 0 on success, otherwise a negative error code.
85  **/
iioutils_get_type(unsigned int * is_signed,unsigned int * bytes,unsigned int * bits_used,unsigned int * shift,uint64_t * mask,unsigned int * be,const char * device_dir,int buffer_idx,const char * name,const char * generic_name)86 static int iioutils_get_type(unsigned int *is_signed, unsigned int *bytes,
87 			     unsigned int *bits_used, unsigned int *shift,
88 			     uint64_t *mask, unsigned int *be,
89 			     const char *device_dir, int buffer_idx,
90 			     const char *name, const char *generic_name)
91 {
92 	FILE *sysfsfp;
93 	int ret;
94 	DIR *dp;
95 	char *scan_el_dir, *builtname, *builtname_generic, *filename = 0;
96 	char signchar, endianchar;
97 	unsigned padint;
98 	const struct dirent *ent;
99 
100 	ret = asprintf(&scan_el_dir, FORMAT_SCAN_ELEMENTS_DIR, device_dir, buffer_idx);
101 	if (ret < 0)
102 		return -ENOMEM;
103 
104 	ret = asprintf(&builtname, FORMAT_TYPE_FILE, name);
105 	if (ret < 0) {
106 		ret = -ENOMEM;
107 		goto error_free_scan_el_dir;
108 	}
109 	ret = asprintf(&builtname_generic, FORMAT_TYPE_FILE, generic_name);
110 	if (ret < 0) {
111 		ret = -ENOMEM;
112 		goto error_free_builtname;
113 	}
114 
115 	dp = opendir(scan_el_dir);
116 	if (!dp) {
117 		ret = -errno;
118 		goto error_free_builtname_generic;
119 	}
120 
121 	ret = -ENOENT;
122 	while (ent = readdir(dp), ent)
123 		if ((strcmp(builtname, ent->d_name) == 0) ||
124 		    (strcmp(builtname_generic, ent->d_name) == 0)) {
125 			ret = asprintf(&filename,
126 				       "%s/%s", scan_el_dir, ent->d_name);
127 			if (ret < 0) {
128 				ret = -ENOMEM;
129 				goto error_closedir;
130 			}
131 
132 			sysfsfp = fopen(filename, "r");
133 			if (!sysfsfp) {
134 				ret = -errno;
135 				fprintf(stderr, "failed to open %s\n",
136 					filename);
137 				goto error_free_filename;
138 			}
139 
140 			ret = fscanf(sysfsfp,
141 				     "%ce:%c%u/%u>>%u",
142 				     &endianchar,
143 				     &signchar,
144 				     bits_used,
145 				     &padint, shift);
146 			if (ret < 0) {
147 				ret = -errno;
148 				fprintf(stderr,
149 					"failed to pass scan type description\n");
150 				goto error_close_sysfsfp;
151 			} else if (ret != 5) {
152 				ret = -EIO;
153 				fprintf(stderr,
154 					"scan type description didn't match\n");
155 				goto error_close_sysfsfp;
156 			}
157 
158 			*be = (endianchar == 'b');
159 			*bytes = padint / 8;
160 			if (*bits_used == 64)
161 				*mask = ~(0ULL);
162 			else
163 				*mask = (1ULL << *bits_used) - 1ULL;
164 
165 			*is_signed = (signchar == 's');
166 			if (fclose(sysfsfp)) {
167 				ret = -errno;
168 				fprintf(stderr, "Failed to close %s\n",
169 					filename);
170 				goto error_free_filename;
171 			}
172 
173 			sysfsfp = 0;
174 			free(filename);
175 			filename = 0;
176 
177 			/*
178 			 * Avoid having a more generic entry overwriting
179 			 * the settings.
180 			 */
181 			if (strcmp(builtname, ent->d_name) == 0)
182 				break;
183 		}
184 
185 error_close_sysfsfp:
186 	if (sysfsfp)
187 		if (fclose(sysfsfp))
188 			perror("iioutils_get_type(): Failed to close file");
189 
190 error_free_filename:
191 	if (filename)
192 		free(filename);
193 
194 error_closedir:
195 	if (closedir(dp) == -1)
196 		perror("iioutils_get_type(): Failed to close directory");
197 
198 error_free_builtname_generic:
199 	free(builtname_generic);
200 error_free_builtname:
201 	free(builtname);
202 error_free_scan_el_dir:
203 	free(scan_el_dir);
204 
205 	return ret;
206 }
207 
208 /**
209  * iioutils_get_param_float() - read a float value from a channel parameter
210  * @output: output the float value
211  * @param_name: the parameter name to read
212  * @device_dir: the IIO device directory in sysfs
213  * @name: the channel name
214  * @generic_name: the channel type name
215  *
216  * Returns a value >= 0 on success, otherwise a negative error code.
217  **/
iioutils_get_param_float(float * output,const char * param_name,const char * device_dir,const char * name,const char * generic_name)218 int iioutils_get_param_float(float *output, const char *param_name,
219 			     const char *device_dir, const char *name,
220 			     const char *generic_name)
221 {
222 	FILE *sysfsfp;
223 	int ret;
224 	DIR *dp;
225 	char *builtname, *builtname_generic;
226 	char *filename = NULL;
227 	const struct dirent *ent;
228 
229 	ret = asprintf(&builtname, "%s_%s", name, param_name);
230 	if (ret < 0)
231 		return -ENOMEM;
232 
233 	ret = asprintf(&builtname_generic,
234 		       "%s_%s", generic_name, param_name);
235 	if (ret < 0) {
236 		ret = -ENOMEM;
237 		goto error_free_builtname;
238 	}
239 
240 	dp = opendir(device_dir);
241 	if (!dp) {
242 		ret = -errno;
243 		goto error_free_builtname_generic;
244 	}
245 
246 	ret = -ENOENT;
247 	while (ent = readdir(dp), ent)
248 		if ((strcmp(builtname, ent->d_name) == 0) ||
249 		    (strcmp(builtname_generic, ent->d_name) == 0)) {
250 			ret = asprintf(&filename,
251 				       "%s/%s", device_dir, ent->d_name);
252 			if (ret < 0) {
253 				ret = -ENOMEM;
254 				goto error_closedir;
255 			}
256 
257 			sysfsfp = fopen(filename, "r");
258 			if (!sysfsfp) {
259 				ret = -errno;
260 				goto error_free_filename;
261 			}
262 
263 			errno = 0;
264 			if (fscanf(sysfsfp, "%f", output) != 1)
265 				ret = errno ? -errno : -ENODATA;
266 
267 			fclose(sysfsfp);
268 			break;
269 		}
270 error_free_filename:
271 	if (filename)
272 		free(filename);
273 
274 error_closedir:
275 	if (closedir(dp) == -1)
276 		perror("iioutils_get_param_float(): Failed to close directory");
277 
278 error_free_builtname_generic:
279 	free(builtname_generic);
280 error_free_builtname:
281 	free(builtname);
282 
283 	return ret;
284 }
285 
286 /**
287  * bsort_channel_array_by_index() - sort the array in index order
288  * @ci_array: the iio_channel_info array to be sorted
289  * @cnt: the amount of array elements
290  **/
291 
bsort_channel_array_by_index(struct iio_channel_info * ci_array,int cnt)292 void bsort_channel_array_by_index(struct iio_channel_info *ci_array, int cnt)
293 {
294 	struct iio_channel_info temp;
295 	int x, y;
296 
297 	for (x = 0; x < cnt; x++)
298 		for (y = 0; y < (cnt - 1); y++)
299 			if (ci_array[y].index > ci_array[y + 1].index) {
300 				temp = ci_array[y + 1];
301 				ci_array[y + 1] = ci_array[y];
302 				ci_array[y] = temp;
303 			}
304 }
305 
306 /**
307  * build_channel_array() - function to figure out what channels are present
308  * @device_dir: the IIO device directory in sysfs
309  * @buffer_idx: the IIO buffer for this channel array
310  * @ci_array: output the resulting array of iio_channel_info
311  * @counter: output the amount of array elements
312  *
313  * Returns 0 on success, otherwise a negative error code.
314  **/
build_channel_array(const char * device_dir,int buffer_idx,struct iio_channel_info ** ci_array,int * counter)315 int build_channel_array(const char *device_dir, int buffer_idx,
316 			struct iio_channel_info **ci_array, int *counter)
317 {
318 	DIR *dp;
319 	FILE *sysfsfp;
320 	int count = 0, i;
321 	struct iio_channel_info *current;
322 	int ret;
323 	const struct dirent *ent;
324 	char *scan_el_dir;
325 	char *filename;
326 
327 	*counter = 0;
328 	ret = asprintf(&scan_el_dir, FORMAT_SCAN_ELEMENTS_DIR, device_dir, buffer_idx);
329 	if (ret < 0)
330 		return -ENOMEM;
331 
332 	dp = opendir(scan_el_dir);
333 	if (!dp) {
334 		ret = -errno;
335 		goto error_free_name;
336 	}
337 
338 	while (ent = readdir(dp), ent)
339 		if (strcmp(ent->d_name + strlen(ent->d_name) - strlen("_en"),
340 			   "_en") == 0) {
341 			ret = asprintf(&filename,
342 				       "%s/%s", scan_el_dir, ent->d_name);
343 			if (ret < 0) {
344 				ret = -ENOMEM;
345 				goto error_close_dir;
346 			}
347 
348 			sysfsfp = fopen(filename, "r");
349 			free(filename);
350 			if (!sysfsfp) {
351 				ret = -errno;
352 				goto error_close_dir;
353 			}
354 
355 			errno = 0;
356 			if (fscanf(sysfsfp, "%i", &ret) != 1) {
357 				ret = errno ? -errno : -ENODATA;
358 				if (fclose(sysfsfp))
359 					perror("build_channel_array(): Failed to close file");
360 
361 				goto error_close_dir;
362 			}
363 			if (ret == 1)
364 				(*counter)++;
365 
366 			if (fclose(sysfsfp)) {
367 				ret = -errno;
368 				goto error_close_dir;
369 			}
370 
371 		}
372 
373 	*ci_array = malloc(sizeof(**ci_array) * (*counter));
374 	if (!*ci_array) {
375 		ret = -ENOMEM;
376 		goto error_close_dir;
377 	}
378 
379 	rewinddir(dp);
380 	while (ent = readdir(dp), ent) {
381 		if (strcmp(ent->d_name + strlen(ent->d_name) - strlen("_en"),
382 			   "_en") == 0) {
383 			int current_enabled = 0;
384 
385 			current = &(*ci_array)[count++];
386 			ret = asprintf(&filename,
387 				       "%s/%s", scan_el_dir, ent->d_name);
388 			if (ret < 0) {
389 				ret = -ENOMEM;
390 				/* decrement count to avoid freeing name */
391 				count--;
392 				goto error_cleanup_array;
393 			}
394 
395 			sysfsfp = fopen(filename, "r");
396 			free(filename);
397 			if (!sysfsfp) {
398 				ret = -errno;
399 				count--;
400 				goto error_cleanup_array;
401 			}
402 
403 			errno = 0;
404 			if (fscanf(sysfsfp, "%i", &current_enabled) != 1) {
405 				ret = errno ? -errno : -ENODATA;
406 				count--;
407 				goto error_cleanup_array;
408 			}
409 
410 			if (fclose(sysfsfp)) {
411 				ret = -errno;
412 				count--;
413 				goto error_cleanup_array;
414 			}
415 
416 			if (!current_enabled) {
417 				count--;
418 				continue;
419 			}
420 
421 			current->scale = 1.0;
422 			current->offset = 0;
423 			current->name = strndup(ent->d_name,
424 						strlen(ent->d_name) -
425 						strlen("_en"));
426 			if (!current->name) {
427 				ret = -ENOMEM;
428 				count--;
429 				goto error_cleanup_array;
430 			}
431 
432 			/* Get the generic and specific name elements */
433 			ret = iioutils_break_up_name(current->name,
434 						     &current->generic_name);
435 			if (ret) {
436 				free(current->name);
437 				count--;
438 				goto error_cleanup_array;
439 			}
440 
441 			ret = asprintf(&filename,
442 				       "%s/%s_index",
443 				       scan_el_dir,
444 				       current->name);
445 			if (ret < 0) {
446 				ret = -ENOMEM;
447 				goto error_cleanup_array;
448 			}
449 
450 			sysfsfp = fopen(filename, "r");
451 			free(filename);
452 			if (!sysfsfp) {
453 				ret = -errno;
454 				fprintf(stderr, "failed to open %s/%s_index\n",
455 					scan_el_dir, current->name);
456 				goto error_cleanup_array;
457 			}
458 
459 			errno = 0;
460 			if (fscanf(sysfsfp, "%u", &current->index) != 1) {
461 				ret = errno ? -errno : -ENODATA;
462 				if (fclose(sysfsfp))
463 					perror("build_channel_array(): Failed to close file");
464 
465 				goto error_cleanup_array;
466 			}
467 
468 			if (fclose(sysfsfp)) {
469 				ret = -errno;
470 				goto error_cleanup_array;
471 			}
472 
473 			/* Find the scale */
474 			ret = iioutils_get_param_float(&current->scale,
475 						       "scale",
476 						       device_dir,
477 						       current->name,
478 						       current->generic_name);
479 			if ((ret < 0) && (ret != -ENOENT))
480 				goto error_cleanup_array;
481 
482 			ret = iioutils_get_param_float(&current->offset,
483 						       "offset",
484 						       device_dir,
485 						       current->name,
486 						       current->generic_name);
487 			if ((ret < 0) && (ret != -ENOENT))
488 				goto error_cleanup_array;
489 
490 			ret = iioutils_get_type(&current->is_signed,
491 						&current->bytes,
492 						&current->bits_used,
493 						&current->shift,
494 						&current->mask,
495 						&current->be,
496 						device_dir,
497 						buffer_idx,
498 						current->name,
499 						current->generic_name);
500 			if (ret < 0)
501 				goto error_cleanup_array;
502 		}
503 	}
504 
505 	if (closedir(dp) == -1) {
506 		ret = -errno;
507 		goto error_cleanup_array;
508 	}
509 
510 	free(scan_el_dir);
511 	/* reorder so that the array is in index order */
512 	bsort_channel_array_by_index(*ci_array, *counter);
513 
514 	return 0;
515 
516 error_cleanup_array:
517 	for (i = count - 1;  i >= 0; i--) {
518 		free((*ci_array)[i].name);
519 		free((*ci_array)[i].generic_name);
520 	}
521 	free(*ci_array);
522 	*ci_array = NULL;
523 	*counter = 0;
524 error_close_dir:
525 	if (dp)
526 		if (closedir(dp) == -1)
527 			perror("build_channel_array(): Failed to close dir");
528 
529 error_free_name:
530 	free(scan_el_dir);
531 
532 	return ret;
533 }
534 
calc_digits(int num)535 static int calc_digits(int num)
536 {
537 	int count = 0;
538 
539 	/* It takes a digit to represent zero */
540 	if (!num)
541 		return 1;
542 
543 	while (num != 0) {
544 		num /= 10;
545 		count++;
546 	}
547 
548 	return count;
549 }
550 
551 /**
552  * find_type_by_name() - function to match top level types by name
553  * @name: top level type instance name
554  * @type: the type of top level instance being searched
555  *
556  * Returns the device number of a matched IIO device on success, otherwise a
557  * negative error code.
558  * Typical types this is used for are device and trigger.
559  **/
find_type_by_name(const char * name,const char * type)560 int find_type_by_name(const char *name, const char *type)
561 {
562 	const struct dirent *ent;
563 	int number, numstrlen, ret;
564 
565 	FILE *namefp;
566 	DIR *dp;
567 	char thisname[IIO_MAX_NAME_LENGTH];
568 	char *filename;
569 
570 	dp = opendir(iio_dir);
571 	if (!dp) {
572 		fprintf(stderr, "No industrialio devices available\n");
573 		return -ENODEV;
574 	}
575 
576 	while (ent = readdir(dp), ent) {
577 		if (strcmp(ent->d_name, ".") != 0 &&
578 		    strcmp(ent->d_name, "..") != 0 &&
579 		    strlen(ent->d_name) > strlen(type) &&
580 		    strncmp(ent->d_name, type, strlen(type)) == 0) {
581 			errno = 0;
582 			ret = sscanf(ent->d_name + strlen(type), "%d", &number);
583 			if (ret < 0) {
584 				ret = -errno;
585 				fprintf(stderr,
586 					"failed to read element number\n");
587 				goto error_close_dir;
588 			} else if (ret != 1) {
589 				ret = -EIO;
590 				fprintf(stderr,
591 					"failed to match element number\n");
592 				goto error_close_dir;
593 			}
594 
595 			numstrlen = calc_digits(number);
596 			/* verify the next character is not a colon */
597 			if (strncmp(ent->d_name + strlen(type) + numstrlen,
598 			    ":", 1) != 0) {
599 				filename = malloc(strlen(iio_dir) + strlen(type)
600 						  + numstrlen + 6);
601 				if (!filename) {
602 					ret = -ENOMEM;
603 					goto error_close_dir;
604 				}
605 
606 				ret = sprintf(filename, "%s%s%d/name", iio_dir,
607 					      type, number);
608 				if (ret < 0) {
609 					free(filename);
610 					goto error_close_dir;
611 				}
612 
613 				namefp = fopen(filename, "r");
614 				if (!namefp) {
615 					free(filename);
616 					continue;
617 				}
618 
619 				free(filename);
620 				errno = 0;
621 				if (fscanf(namefp, "%s", thisname) != 1) {
622 					ret = errno ? -errno : -ENODATA;
623 					goto error_close_dir;
624 				}
625 
626 				if (fclose(namefp)) {
627 					ret = -errno;
628 					goto error_close_dir;
629 				}
630 
631 				if (strcmp(name, thisname) == 0) {
632 					if (closedir(dp) == -1)
633 						return -errno;
634 
635 					return number;
636 				}
637 			}
638 		}
639 	}
640 	if (closedir(dp) == -1)
641 		return -errno;
642 
643 	return -ENODEV;
644 
645 error_close_dir:
646 	if (closedir(dp) == -1)
647 		perror("find_type_by_name(): Failed to close directory");
648 
649 	return ret;
650 }
651 
_write_sysfs_int(const char * filename,const char * basedir,int val,int verify)652 static int _write_sysfs_int(const char *filename, const char *basedir, int val,
653 			    int verify)
654 {
655 	int ret = 0;
656 	FILE *sysfsfp;
657 	int test;
658 	char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
659 
660 	if (!temp)
661 		return -ENOMEM;
662 
663 	ret = sprintf(temp, "%s/%s", basedir, filename);
664 	if (ret < 0)
665 		goto error_free;
666 
667 	sysfsfp = fopen(temp, "w");
668 	if (!sysfsfp) {
669 		ret = -errno;
670 		fprintf(stderr, "failed to open %s\n", temp);
671 		goto error_free;
672 	}
673 
674 	ret = fprintf(sysfsfp, "%d", val);
675 	if (ret < 0) {
676 		if (fclose(sysfsfp))
677 			perror("_write_sysfs_int(): Failed to close dir");
678 
679 		goto error_free;
680 	}
681 
682 	if (fclose(sysfsfp)) {
683 		ret = -errno;
684 		goto error_free;
685 	}
686 
687 	if (verify) {
688 		sysfsfp = fopen(temp, "r");
689 		if (!sysfsfp) {
690 			ret = -errno;
691 			fprintf(stderr, "failed to open %s\n", temp);
692 			goto error_free;
693 		}
694 
695 		if (fscanf(sysfsfp, "%d", &test) != 1) {
696 			ret = errno ? -errno : -ENODATA;
697 			if (fclose(sysfsfp))
698 				perror("_write_sysfs_int(): Failed to close dir");
699 
700 			goto error_free;
701 		}
702 
703 		if (fclose(sysfsfp)) {
704 			ret = -errno;
705 			goto error_free;
706 		}
707 
708 		if (test != val) {
709 			fprintf(stderr,
710 				"Possible failure in int write %d to %s/%s\n",
711 				val, basedir, filename);
712 			ret = -1;
713 		}
714 	}
715 
716 error_free:
717 	free(temp);
718 	return ret;
719 }
720 
721 /**
722  * write_sysfs_int() - write an integer value to a sysfs file
723  * @filename: name of the file to write to
724  * @basedir: the sysfs directory in which the file is to be found
725  * @val: integer value to write to file
726  *
727  * Returns a value >= 0 on success, otherwise a negative error code.
728  **/
write_sysfs_int(const char * filename,const char * basedir,int val)729 int write_sysfs_int(const char *filename, const char *basedir, int val)
730 {
731 	return _write_sysfs_int(filename, basedir, val, 0);
732 }
733 
734 /**
735  * write_sysfs_int_and_verify() - write an integer value to a sysfs file
736  *				  and verify
737  * @filename: name of the file to write to
738  * @basedir: the sysfs directory in which the file is to be found
739  * @val: integer value to write to file
740  *
741  * Returns a value >= 0 on success, otherwise a negative error code.
742  **/
write_sysfs_int_and_verify(const char * filename,const char * basedir,int val)743 int write_sysfs_int_and_verify(const char *filename, const char *basedir,
744 			       int val)
745 {
746 	return _write_sysfs_int(filename, basedir, val, 1);
747 }
748 
_write_sysfs_string(const char * filename,const char * basedir,const char * val,int verify)749 static int _write_sysfs_string(const char *filename, const char *basedir,
750 			       const char *val, int verify)
751 {
752 	int ret = 0;
753 	FILE  *sysfsfp;
754 	char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
755 
756 	if (!temp) {
757 		fprintf(stderr, "Memory allocation failed\n");
758 		return -ENOMEM;
759 	}
760 
761 	ret = sprintf(temp, "%s/%s", basedir, filename);
762 	if (ret < 0)
763 		goto error_free;
764 
765 	sysfsfp = fopen(temp, "w");
766 	if (!sysfsfp) {
767 		ret = -errno;
768 		fprintf(stderr, "Could not open %s\n", temp);
769 		goto error_free;
770 	}
771 
772 	ret = fprintf(sysfsfp, "%s", val);
773 	if (ret < 0) {
774 		if (fclose(sysfsfp))
775 			perror("_write_sysfs_string(): Failed to close dir");
776 
777 		goto error_free;
778 	}
779 
780 	if (fclose(sysfsfp)) {
781 		ret = -errno;
782 		goto error_free;
783 	}
784 
785 	if (verify) {
786 		sysfsfp = fopen(temp, "r");
787 		if (!sysfsfp) {
788 			ret = -errno;
789 			fprintf(stderr, "Could not open file to verify\n");
790 			goto error_free;
791 		}
792 
793 		if (fscanf(sysfsfp, "%s", temp) != 1) {
794 			ret = errno ? -errno : -ENODATA;
795 			if (fclose(sysfsfp))
796 				perror("_write_sysfs_string(): Failed to close dir");
797 
798 			goto error_free;
799 		}
800 
801 		if (fclose(sysfsfp)) {
802 			ret = -errno;
803 			goto error_free;
804 		}
805 
806 		if (strcmp(temp, val) != 0) {
807 			fprintf(stderr,
808 				"Possible failure in string write of %s "
809 				"Should be %s written to %s/%s\n", temp, val,
810 				basedir, filename);
811 			ret = -1;
812 		}
813 	}
814 
815 error_free:
816 	free(temp);
817 
818 	return ret;
819 }
820 
821 /**
822  * write_sysfs_string_and_verify() - string write, readback and verify
823  * @filename: name of file to write to
824  * @basedir: the sysfs directory in which the file is to be found
825  * @val: the string to write
826  *
827  * Returns a value >= 0 on success, otherwise a negative error code.
828  **/
write_sysfs_string_and_verify(const char * filename,const char * basedir,const char * val)829 int write_sysfs_string_and_verify(const char *filename, const char *basedir,
830 				  const char *val)
831 {
832 	return _write_sysfs_string(filename, basedir, val, 1);
833 }
834 
835 /**
836  * write_sysfs_string() - write string to a sysfs file
837  * @filename: name of file to write to
838  * @basedir: the sysfs directory in which the file is to be found
839  * @val: the string to write
840  *
841  * Returns a value >= 0 on success, otherwise a negative error code.
842  **/
write_sysfs_string(const char * filename,const char * basedir,const char * val)843 int write_sysfs_string(const char *filename, const char *basedir,
844 		       const char *val)
845 {
846 	return _write_sysfs_string(filename, basedir, val, 0);
847 }
848 
849 /**
850  * read_sysfs_posint() - read an integer value from file
851  * @filename: name of file to read from
852  * @basedir: the sysfs directory in which the file is to be found
853  *
854  * Returns the read integer value >= 0 on success, otherwise a negative error
855  * code.
856  **/
read_sysfs_posint(const char * filename,const char * basedir)857 int read_sysfs_posint(const char *filename, const char *basedir)
858 {
859 	int ret;
860 	FILE  *sysfsfp;
861 	char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
862 
863 	if (!temp) {
864 		fprintf(stderr, "Memory allocation failed");
865 		return -ENOMEM;
866 	}
867 
868 	ret = sprintf(temp, "%s/%s", basedir, filename);
869 	if (ret < 0)
870 		goto error_free;
871 
872 	sysfsfp = fopen(temp, "r");
873 	if (!sysfsfp) {
874 		ret = -errno;
875 		goto error_free;
876 	}
877 
878 	errno = 0;
879 	if (fscanf(sysfsfp, "%d\n", &ret) != 1) {
880 		ret = errno ? -errno : -ENODATA;
881 		if (fclose(sysfsfp))
882 			perror("read_sysfs_posint(): Failed to close dir");
883 
884 		goto error_free;
885 	}
886 
887 	if (fclose(sysfsfp))
888 		ret = -errno;
889 
890 error_free:
891 	free(temp);
892 
893 	return ret;
894 }
895 
896 /**
897  * read_sysfs_float() - read a float value from file
898  * @filename: name of file to read from
899  * @basedir: the sysfs directory in which the file is to be found
900  * @val: output the read float value
901  *
902  * Returns a value >= 0 on success, otherwise a negative error code.
903  **/
read_sysfs_float(const char * filename,const char * basedir,float * val)904 int read_sysfs_float(const char *filename, const char *basedir, float *val)
905 {
906 	int ret = 0;
907 	FILE  *sysfsfp;
908 	char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
909 
910 	if (!temp) {
911 		fprintf(stderr, "Memory allocation failed");
912 		return -ENOMEM;
913 	}
914 
915 	ret = sprintf(temp, "%s/%s", basedir, filename);
916 	if (ret < 0)
917 		goto error_free;
918 
919 	sysfsfp = fopen(temp, "r");
920 	if (!sysfsfp) {
921 		ret = -errno;
922 		goto error_free;
923 	}
924 
925 	errno = 0;
926 	if (fscanf(sysfsfp, "%f\n", val) != 1) {
927 		ret = errno ? -errno : -ENODATA;
928 		if (fclose(sysfsfp))
929 			perror("read_sysfs_float(): Failed to close dir");
930 
931 		goto error_free;
932 	}
933 
934 	if (fclose(sysfsfp))
935 		ret = -errno;
936 
937 error_free:
938 	free(temp);
939 
940 	return ret;
941 }
942 
943 /**
944  * read_sysfs_string() - read a string from file
945  * @filename: name of file to read from
946  * @basedir: the sysfs directory in which the file is to be found
947  * @str: output the read string
948  *
949  * Returns a value >= 0 on success, otherwise a negative error code.
950  **/
read_sysfs_string(const char * filename,const char * basedir,char * str)951 int read_sysfs_string(const char *filename, const char *basedir, char *str)
952 {
953 	int ret = 0;
954 	FILE  *sysfsfp;
955 	char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
956 
957 	if (!temp) {
958 		fprintf(stderr, "Memory allocation failed");
959 		return -ENOMEM;
960 	}
961 
962 	ret = sprintf(temp, "%s/%s", basedir, filename);
963 	if (ret < 0)
964 		goto error_free;
965 
966 	sysfsfp = fopen(temp, "r");
967 	if (!sysfsfp) {
968 		ret = -errno;
969 		goto error_free;
970 	}
971 
972 	errno = 0;
973 	if (fscanf(sysfsfp, "%s\n", str) != 1) {
974 		ret = errno ? -errno : -ENODATA;
975 		if (fclose(sysfsfp))
976 			perror("read_sysfs_string(): Failed to close dir");
977 
978 		goto error_free;
979 	}
980 
981 	if (fclose(sysfsfp))
982 		ret = -errno;
983 
984 error_free:
985 	free(temp);
986 
987 	return ret;
988 }
989