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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
15const char *iio_dir = "/sys/bus/iio/devices/";
16
17static 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 **/
29int 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 * @name: the channel name
81 * @generic_name: the channel type name
82 *
83 * Returns a value >= 0 on success, otherwise a negative error code.
84 **/
85int iioutils_get_type(unsigned *is_signed, unsigned *bytes, unsigned *bits_used,
86 unsigned *shift, uint64_t *mask, unsigned *be,
87 const char *device_dir, const char *name,
88 const char *generic_name)
89{
90 FILE *sysfsfp;
91 int ret;
92 DIR *dp;
93 char *scan_el_dir, *builtname, *builtname_generic, *filename = 0;
94 char signchar, endianchar;
95 unsigned padint;
96 const struct dirent *ent;
97
98 ret = asprintf(&scan_el_dir, FORMAT_SCAN_ELEMENTS_DIR, device_dir);
99 if (ret < 0)
100 return -ENOMEM;
101
102 ret = asprintf(&builtname, FORMAT_TYPE_FILE, name);
103 if (ret < 0) {
104 ret = -ENOMEM;
105 goto error_free_scan_el_dir;
106 }
107 ret = asprintf(&builtname_generic, FORMAT_TYPE_FILE, generic_name);
108 if (ret < 0) {
109 ret = -ENOMEM;
110 goto error_free_builtname;
111 }
112
113 dp = opendir(scan_el_dir);
114 if (!dp) {
115 ret = -errno;
116 goto error_free_builtname_generic;
117 }
118
119 ret = -ENOENT;
120 while (ent = readdir(dp), ent)
121 if ((strcmp(builtname, ent->d_name) == 0) ||
122 (strcmp(builtname_generic, ent->d_name) == 0)) {
123 ret = asprintf(&filename,
124 "%s/%s", scan_el_dir, ent->d_name);
125 if (ret < 0) {
126 ret = -ENOMEM;
127 goto error_closedir;
128 }
129
130 sysfsfp = fopen(filename, "r");
131 if (!sysfsfp) {
132 ret = -errno;
133 fprintf(stderr, "failed to open %s\n",
134 filename);
135 goto error_free_filename;
136 }
137
138 ret = fscanf(sysfsfp,
139 "%ce:%c%u/%u>>%u",
140 &endianchar,
141 &signchar,
142 bits_used,
143 &padint, shift);
144 if (ret < 0) {
145 ret = -errno;
146 fprintf(stderr,
147 "failed to pass scan type description\n");
148 goto error_close_sysfsfp;
149 } else if (ret != 5) {
150 ret = -EIO;
151 fprintf(stderr,
152 "scan type description didn't match\n");
153 goto error_close_sysfsfp;
154 }
155
156 *be = (endianchar == 'b');
157 *bytes = padint / 8;
158 if (*bits_used == 64)
159 *mask = ~(0ULL);
160 else
161 *mask = (1ULL << *bits_used) - 1ULL;
162
163 *is_signed = (signchar == 's');
164 if (fclose(sysfsfp)) {
165 ret = -errno;
166 fprintf(stderr, "Failed to close %s\n",
167 filename);
168 goto error_free_filename;
169 }
170
171 sysfsfp = 0;
172 free(filename);
173 filename = 0;
174
175 /*
176 * Avoid having a more generic entry overwriting
177 * the settings.
178 */
179 if (strcmp(builtname, ent->d_name) == 0)
180 break;
181 }
182
183error_close_sysfsfp:
184 if (sysfsfp)
185 if (fclose(sysfsfp))
186 perror("iioutils_get_type(): Failed to close file");
187
188error_free_filename:
189 if (filename)
190 free(filename);
191
192error_closedir:
193 if (closedir(dp) == -1)
194 perror("iioutils_get_type(): Failed to close directory");
195
196error_free_builtname_generic:
197 free(builtname_generic);
198error_free_builtname:
199 free(builtname);
200error_free_scan_el_dir:
201 free(scan_el_dir);
202
203 return ret;
204}
205
206/**
207 * iioutils_get_param_float() - read a float value from a channel parameter
208 * @output: output the float value
209 * @param_name: the parameter name to read
210 * @device_dir: the IIO device directory in sysfs
211 * @name: the channel name
212 * @generic_name: the channel type name
213 *
214 * Returns a value >= 0 on success, otherwise a negative error code.
215 **/
216int iioutils_get_param_float(float *output, const char *param_name,
217 const char *device_dir, const char *name,
218 const char *generic_name)
219{
220 FILE *sysfsfp;
221 int ret;
222 DIR *dp;
223 char *builtname, *builtname_generic;
224 char *filename = NULL;
225 const struct dirent *ent;
226
227 ret = asprintf(&builtname, "%s_%s", name, param_name);
228 if (ret < 0)
229 return -ENOMEM;
230
231 ret = asprintf(&builtname_generic,
232 "%s_%s", generic_name, param_name);
233 if (ret < 0) {
234 ret = -ENOMEM;
235 goto error_free_builtname;
236 }
237
238 dp = opendir(device_dir);
239 if (!dp) {
240 ret = -errno;
241 goto error_free_builtname_generic;
242 }
243
244 ret = -ENOENT;
245 while (ent = readdir(dp), ent)
246 if ((strcmp(builtname, ent->d_name) == 0) ||
247 (strcmp(builtname_generic, ent->d_name) == 0)) {
248 ret = asprintf(&filename,
249 "%s/%s", device_dir, ent->d_name);
250 if (ret < 0) {
251 ret = -ENOMEM;
252 goto error_closedir;
253 }
254
255 sysfsfp = fopen(filename, "r");
256 if (!sysfsfp) {
257 ret = -errno;
258 goto error_free_filename;
259 }
260
261 errno = 0;
262 if (fscanf(sysfsfp, "%f", output) != 1)
263 ret = errno ? -errno : -ENODATA;
264
265 break;
266 }
267error_free_filename:
268 if (filename)
269 free(filename);
270
271error_closedir:
272 if (closedir(dp) == -1)
273 perror("iioutils_get_param_float(): Failed to close directory");
274
275error_free_builtname_generic:
276 free(builtname_generic);
277error_free_builtname:
278 free(builtname);
279
280 return ret;
281}
282
283/**
284 * bsort_channel_array_by_index() - sort the array in index order
285 * @ci_array: the iio_channel_info array to be sorted
286 * @cnt: the amount of array elements
287 **/
288
289void bsort_channel_array_by_index(struct iio_channel_info *ci_array, int cnt)
290{
291 struct iio_channel_info temp;
292 int x, y;
293
294 for (x = 0; x < cnt; x++)
295 for (y = 0; y < (cnt - 1); y++)
296 if (ci_array[y].index > ci_array[y + 1].index) {
297 temp = ci_array[y + 1];
298 ci_array[y + 1] = ci_array[y];
299 ci_array[y] = temp;
300 }
301}
302
303/**
304 * build_channel_array() - function to figure out what channels are present
305 * @device_dir: the IIO device directory in sysfs
306 * @ci_array: output the resulting array of iio_channel_info
307 * @counter: output the amount of array elements
308 *
309 * Returns 0 on success, otherwise a negative error code.
310 **/
311int build_channel_array(const char *device_dir,
312 struct iio_channel_info **ci_array, int *counter)
313{
314 DIR *dp;
315 FILE *sysfsfp;
316 int count = 0, i;
317 struct iio_channel_info *current;
318 int ret;
319 const struct dirent *ent;
320 char *scan_el_dir;
321 char *filename;
322
323 *counter = 0;
324 ret = asprintf(&scan_el_dir, FORMAT_SCAN_ELEMENTS_DIR, device_dir);
325 if (ret < 0)
326 return -ENOMEM;
327
328 dp = opendir(scan_el_dir);
329 if (!dp) {
330 ret = -errno;
331 goto error_free_name;
332 }
333
334 while (ent = readdir(dp), ent)
335 if (strcmp(ent->d_name + strlen(ent->d_name) - strlen("_en"),
336 "_en") == 0) {
337 ret = asprintf(&filename,
338 "%s/%s", scan_el_dir, ent->d_name);
339 if (ret < 0) {
340 ret = -ENOMEM;
341 goto error_close_dir;
342 }
343
344 sysfsfp = fopen(filename, "r");
345 if (!sysfsfp) {
346 ret = -errno;
347 free(filename);
348 goto error_close_dir;
349 }
350
351 errno = 0;
352 if (fscanf(sysfsfp, "%i", &ret) != 1) {
353 ret = errno ? -errno : -ENODATA;
354 if (fclose(sysfsfp))
355 perror("build_channel_array(): Failed to close file");
356
357 free(filename);
358 goto error_close_dir;
359 }
360 if (ret == 1)
361 (*counter)++;
362
363 if (fclose(sysfsfp)) {
364 ret = -errno;
365 free(filename);
366 goto error_close_dir;
367 }
368
369 free(filename);
370 }
371
372 *ci_array = malloc(sizeof(**ci_array) * (*counter));
373 if (!*ci_array) {
374 ret = -ENOMEM;
375 goto error_close_dir;
376 }
377
378 seekdir(dp, 0);
379 while (ent = readdir(dp), ent) {
380 if (strcmp(ent->d_name + strlen(ent->d_name) - strlen("_en"),
381 "_en") == 0) {
382 int current_enabled = 0;
383
384 current = &(*ci_array)[count++];
385 ret = asprintf(&filename,
386 "%s/%s", scan_el_dir, ent->d_name);
387 if (ret < 0) {
388 ret = -ENOMEM;
389 /* decrement count to avoid freeing name */
390 count--;
391 goto error_cleanup_array;
392 }
393
394 sysfsfp = fopen(filename, "r");
395 if (!sysfsfp) {
396 ret = -errno;
397 free(filename);
398 count--;
399 goto error_cleanup_array;
400 }
401
402 errno = 0;
403 if (fscanf(sysfsfp, "%i", ¤t_enabled) != 1) {
404 ret = errno ? -errno : -ENODATA;
405 free(filename);
406 count--;
407 goto error_cleanup_array;
408 }
409
410 if (fclose(sysfsfp)) {
411 ret = -errno;
412 free(filename);
413 count--;
414 goto error_cleanup_array;
415 }
416
417 if (!current_enabled) {
418 free(filename);
419 count--;
420 continue;
421 }
422
423 current->scale = 1.0;
424 current->offset = 0;
425 current->name = strndup(ent->d_name,
426 strlen(ent->d_name) -
427 strlen("_en"));
428 if (!current->name) {
429 free(filename);
430 ret = -ENOMEM;
431 count--;
432 goto error_cleanup_array;
433 }
434
435 /* Get the generic and specific name elements */
436 ret = iioutils_break_up_name(current->name,
437 ¤t->generic_name);
438 if (ret) {
439 free(filename);
440 free(current->name);
441 count--;
442 goto error_cleanup_array;
443 }
444
445 ret = asprintf(&filename,
446 "%s/%s_index",
447 scan_el_dir,
448 current->name);
449 if (ret < 0) {
450 free(filename);
451 ret = -ENOMEM;
452 goto error_cleanup_array;
453 }
454
455 sysfsfp = fopen(filename, "r");
456 if (!sysfsfp) {
457 ret = -errno;
458 fprintf(stderr, "failed to open %s\n",
459 filename);
460 free(filename);
461 goto error_cleanup_array;
462 }
463
464 errno = 0;
465 if (fscanf(sysfsfp, "%u", ¤t->index) != 1) {
466 ret = errno ? -errno : -ENODATA;
467 if (fclose(sysfsfp))
468 perror("build_channel_array(): Failed to close file");
469
470 free(filename);
471 goto error_cleanup_array;
472 }
473
474 if (fclose(sysfsfp)) {
475 ret = -errno;
476 free(filename);
477 goto error_cleanup_array;
478 }
479
480 free(filename);
481 /* Find the scale */
482 ret = iioutils_get_param_float(¤t->scale,
483 "scale",
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_param_float(¤t->offset,
491 "offset",
492 device_dir,
493 current->name,
494 current->generic_name);
495 if ((ret < 0) && (ret != -ENOENT))
496 goto error_cleanup_array;
497
498 ret = iioutils_get_type(¤t->is_signed,
499 ¤t->bytes,
500 ¤t->bits_used,
501 ¤t->shift,
502 ¤t->mask,
503 ¤t->be,
504 device_dir,
505 current->name,
506 current->generic_name);
507 if (ret < 0)
508 goto error_cleanup_array;
509 }
510 }
511
512 if (closedir(dp) == -1) {
513 ret = -errno;
514 goto error_cleanup_array;
515 }
516
517 free(scan_el_dir);
518 /* reorder so that the array is in index order */
519 bsort_channel_array_by_index(*ci_array, *counter);
520
521 return 0;
522
523error_cleanup_array:
524 for (i = count - 1; i >= 0; i--) {
525 free((*ci_array)[i].name);
526 free((*ci_array)[i].generic_name);
527 }
528 free(*ci_array);
529 *ci_array = NULL;
530 *counter = 0;
531error_close_dir:
532 if (dp)
533 if (closedir(dp) == -1)
534 perror("build_channel_array(): Failed to close dir");
535
536error_free_name:
537 free(scan_el_dir);
538
539 return ret;
540}
541
542static int calc_digits(int num)
543{
544 int count = 0;
545
546 while (num != 0) {
547 num /= 10;
548 count++;
549 }
550
551 return count;
552}
553
554/**
555 * find_type_by_name() - function to match top level types by name
556 * @name: top level type instance name
557 * @type: the type of top level instance being searched
558 *
559 * Returns the device number of a matched IIO device on success, otherwise a
560 * negative error code.
561 * Typical types this is used for are device and trigger.
562 **/
563int find_type_by_name(const char *name, const char *type)
564{
565 const struct dirent *ent;
566 int number, numstrlen, ret;
567
568 FILE *namefp;
569 DIR *dp;
570 char thisname[IIO_MAX_NAME_LENGTH];
571 char *filename;
572
573 dp = opendir(iio_dir);
574 if (!dp) {
575 fprintf(stderr, "No industrialio devices available\n");
576 return -ENODEV;
577 }
578
579 while (ent = readdir(dp), ent) {
580 if (strcmp(ent->d_name, ".") != 0 &&
581 strcmp(ent->d_name, "..") != 0 &&
582 strlen(ent->d_name) > strlen(type) &&
583 strncmp(ent->d_name, type, strlen(type)) == 0) {
584 errno = 0;
585 ret = sscanf(ent->d_name + strlen(type), "%d", &number);
586 if (ret < 0) {
587 ret = -errno;
588 fprintf(stderr,
589 "failed to read element number\n");
590 goto error_close_dir;
591 } else if (ret != 1) {
592 ret = -EIO;
593 fprintf(stderr,
594 "failed to match element number\n");
595 goto error_close_dir;
596 }
597
598 numstrlen = calc_digits(number);
599 /* verify the next character is not a colon */
600 if (strncmp(ent->d_name + strlen(type) + numstrlen,
601 ":", 1) != 0) {
602 filename = malloc(strlen(iio_dir) + strlen(type)
603 + numstrlen + 6);
604 if (!filename) {
605 ret = -ENOMEM;
606 goto error_close_dir;
607 }
608
609 ret = sprintf(filename, "%s%s%d/name", iio_dir,
610 type, number);
611 if (ret < 0) {
612 free(filename);
613 goto error_close_dir;
614 }
615
616 namefp = fopen(filename, "r");
617 if (!namefp) {
618 free(filename);
619 continue;
620 }
621
622 free(filename);
623 errno = 0;
624 if (fscanf(namefp, "%s", thisname) != 1) {
625 ret = errno ? -errno : -ENODATA;
626 goto error_close_dir;
627 }
628
629 if (fclose(namefp)) {
630 ret = -errno;
631 goto error_close_dir;
632 }
633
634 if (strcmp(name, thisname) == 0) {
635 if (closedir(dp) == -1)
636 return -errno;
637
638 return number;
639 }
640 }
641 }
642 }
643 if (closedir(dp) == -1)
644 return -errno;
645
646 return -ENODEV;
647
648error_close_dir:
649 if (closedir(dp) == -1)
650 perror("find_type_by_name(): Failed to close directory");
651
652 return ret;
653}
654
655static int _write_sysfs_int(const char *filename, const char *basedir, int val,
656 int verify)
657{
658 int ret = 0;
659 FILE *sysfsfp;
660 int test;
661 char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
662
663 if (!temp)
664 return -ENOMEM;
665
666 ret = sprintf(temp, "%s/%s", basedir, filename);
667 if (ret < 0)
668 goto error_free;
669
670 sysfsfp = fopen(temp, "w");
671 if (!sysfsfp) {
672 ret = -errno;
673 fprintf(stderr, "failed to open %s\n", temp);
674 goto error_free;
675 }
676
677 ret = fprintf(sysfsfp, "%d", val);
678 if (ret < 0) {
679 if (fclose(sysfsfp))
680 perror("_write_sysfs_int(): Failed to close dir");
681
682 goto error_free;
683 }
684
685 if (fclose(sysfsfp)) {
686 ret = -errno;
687 goto error_free;
688 }
689
690 if (verify) {
691 sysfsfp = fopen(temp, "r");
692 if (!sysfsfp) {
693 ret = -errno;
694 fprintf(stderr, "failed to open %s\n", temp);
695 goto error_free;
696 }
697
698 if (fscanf(sysfsfp, "%d", &test) != 1) {
699 ret = errno ? -errno : -ENODATA;
700 if (fclose(sysfsfp))
701 perror("_write_sysfs_int(): Failed to close dir");
702
703 goto error_free;
704 }
705
706 if (fclose(sysfsfp)) {
707 ret = -errno;
708 goto error_free;
709 }
710
711 if (test != val) {
712 fprintf(stderr,
713 "Possible failure in int write %d to %s/%s\n",
714 val, basedir, filename);
715 ret = -1;
716 }
717 }
718
719error_free:
720 free(temp);
721 return ret;
722}
723
724/**
725 * write_sysfs_int() - write an integer value to a sysfs file
726 * @filename: name of the file to write to
727 * @basedir: the sysfs directory in which the file is to be found
728 * @val: integer value to write to file
729 *
730 * Returns a value >= 0 on success, otherwise a negative error code.
731 **/
732int write_sysfs_int(const char *filename, const char *basedir, int val)
733{
734 return _write_sysfs_int(filename, basedir, val, 0);
735}
736
737/**
738 * write_sysfs_int_and_verify() - write an integer value to a sysfs file
739 * and verify
740 * @filename: name of the file to write to
741 * @basedir: the sysfs directory in which the file is to be found
742 * @val: integer value to write to file
743 *
744 * Returns a value >= 0 on success, otherwise a negative error code.
745 **/
746int write_sysfs_int_and_verify(const char *filename, const char *basedir,
747 int val)
748{
749 return _write_sysfs_int(filename, basedir, val, 1);
750}
751
752static int _write_sysfs_string(const char *filename, const char *basedir,
753 const char *val, int verify)
754{
755 int ret = 0;
756 FILE *sysfsfp;
757 char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
758
759 if (!temp) {
760 fprintf(stderr, "Memory allocation failed\n");
761 return -ENOMEM;
762 }
763
764 ret = sprintf(temp, "%s/%s", basedir, filename);
765 if (ret < 0)
766 goto error_free;
767
768 sysfsfp = fopen(temp, "w");
769 if (!sysfsfp) {
770 ret = -errno;
771 fprintf(stderr, "Could not open %s\n", temp);
772 goto error_free;
773 }
774
775 ret = fprintf(sysfsfp, "%s", val);
776 if (ret < 0) {
777 if (fclose(sysfsfp))
778 perror("_write_sysfs_string(): Failed to close dir");
779
780 goto error_free;
781 }
782
783 if (fclose(sysfsfp)) {
784 ret = -errno;
785 goto error_free;
786 }
787
788 if (verify) {
789 sysfsfp = fopen(temp, "r");
790 if (!sysfsfp) {
791 ret = -errno;
792 fprintf(stderr, "Could not open file to verify\n");
793 goto error_free;
794 }
795
796 if (fscanf(sysfsfp, "%s", temp) != 1) {
797 ret = errno ? -errno : -ENODATA;
798 if (fclose(sysfsfp))
799 perror("_write_sysfs_string(): Failed to close dir");
800
801 goto error_free;
802 }
803
804 if (fclose(sysfsfp)) {
805 ret = -errno;
806 goto error_free;
807 }
808
809 if (strcmp(temp, val) != 0) {
810 fprintf(stderr,
811 "Possible failure in string write of %s "
812 "Should be %s written to %s/%s\n", temp, val,
813 basedir, filename);
814 ret = -1;
815 }
816 }
817
818error_free:
819 free(temp);
820
821 return ret;
822}
823
824/**
825 * write_sysfs_string_and_verify() - string write, readback and verify
826 * @filename: name of file to write to
827 * @basedir: the sysfs directory in which the file is to be found
828 * @val: the string to write
829 *
830 * Returns a value >= 0 on success, otherwise a negative error code.
831 **/
832int write_sysfs_string_and_verify(const char *filename, const char *basedir,
833 const char *val)
834{
835 return _write_sysfs_string(filename, basedir, val, 1);
836}
837
838/**
839 * write_sysfs_string() - write string to a sysfs file
840 * @filename: name of file to write to
841 * @basedir: the sysfs directory in which the file is to be found
842 * @val: the string to write
843 *
844 * Returns a value >= 0 on success, otherwise a negative error code.
845 **/
846int write_sysfs_string(const char *filename, const char *basedir,
847 const char *val)
848{
849 return _write_sysfs_string(filename, basedir, val, 0);
850}
851
852/**
853 * read_sysfs_posint() - read an integer value from file
854 * @filename: name of file to read from
855 * @basedir: the sysfs directory in which the file is to be found
856 *
857 * Returns the read integer value >= 0 on success, otherwise a negative error
858 * code.
859 **/
860int read_sysfs_posint(const char *filename, const char *basedir)
861{
862 int ret;
863 FILE *sysfsfp;
864 char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
865
866 if (!temp) {
867 fprintf(stderr, "Memory allocation failed");
868 return -ENOMEM;
869 }
870
871 ret = sprintf(temp, "%s/%s", basedir, filename);
872 if (ret < 0)
873 goto error_free;
874
875 sysfsfp = fopen(temp, "r");
876 if (!sysfsfp) {
877 ret = -errno;
878 goto error_free;
879 }
880
881 errno = 0;
882 if (fscanf(sysfsfp, "%d\n", &ret) != 1) {
883 ret = errno ? -errno : -ENODATA;
884 if (fclose(sysfsfp))
885 perror("read_sysfs_posint(): Failed to close dir");
886
887 goto error_free;
888 }
889
890 if (fclose(sysfsfp))
891 ret = -errno;
892
893error_free:
894 free(temp);
895
896 return ret;
897}
898
899/**
900 * read_sysfs_float() - read a float value from file
901 * @filename: name of file to read from
902 * @basedir: the sysfs directory in which the file is to be found
903 * @val: output the read float value
904 *
905 * Returns a value >= 0 on success, otherwise a negative error code.
906 **/
907int read_sysfs_float(const char *filename, const char *basedir, float *val)
908{
909 int ret = 0;
910 FILE *sysfsfp;
911 char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
912
913 if (!temp) {
914 fprintf(stderr, "Memory allocation failed");
915 return -ENOMEM;
916 }
917
918 ret = sprintf(temp, "%s/%s", basedir, filename);
919 if (ret < 0)
920 goto error_free;
921
922 sysfsfp = fopen(temp, "r");
923 if (!sysfsfp) {
924 ret = -errno;
925 goto error_free;
926 }
927
928 errno = 0;
929 if (fscanf(sysfsfp, "%f\n", val) != 1) {
930 ret = errno ? -errno : -ENODATA;
931 if (fclose(sysfsfp))
932 perror("read_sysfs_float(): Failed to close dir");
933
934 goto error_free;
935 }
936
937 if (fclose(sysfsfp))
938 ret = -errno;
939
940error_free:
941 free(temp);
942
943 return ret;
944}
945
946/**
947 * read_sysfs_string() - read a string from file
948 * @filename: name of file to read from
949 * @basedir: the sysfs directory in which the file is to be found
950 * @str: output the read string
951 *
952 * Returns a value >= 0 on success, otherwise a negative error code.
953 **/
954int read_sysfs_string(const char *filename, const char *basedir, char *str)
955{
956 int ret = 0;
957 FILE *sysfsfp;
958 char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
959
960 if (!temp) {
961 fprintf(stderr, "Memory allocation failed");
962 return -ENOMEM;
963 }
964
965 ret = sprintf(temp, "%s/%s", basedir, filename);
966 if (ret < 0)
967 goto error_free;
968
969 sysfsfp = fopen(temp, "r");
970 if (!sysfsfp) {
971 ret = -errno;
972 goto error_free;
973 }
974
975 errno = 0;
976 if (fscanf(sysfsfp, "%s\n", str) != 1) {
977 ret = errno ? -errno : -ENODATA;
978 if (fclose(sysfsfp))
979 perror("read_sysfs_string(): Failed to close dir");
980
981 goto error_free;
982 }
983
984 if (fclose(sysfsfp))
985 ret = -errno;
986
987error_free:
988 free(temp);
989
990 return ret;
991}