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1/* IIO - useful set of util functionality
2 *
3 * Copyright (c) 2008 Jonathan Cameron
4 *
5 * This program is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 as published by
7 * the Free Software Foundation.
8 */
9#include <string.h>
10#include <stdlib.h>
11#include <stdio.h>
12#include <stdint.h>
13#include <dirent.h>
14#include <errno.h>
15#include <ctype.h>
16#include "iio_utils.h"
17
18const char *iio_dir = "/sys/bus/iio/devices/";
19
20static char * const iio_direction[] = {
21 "in",
22 "out",
23};
24
25/**
26 * iioutils_break_up_name() - extract generic name from full channel name
27 * @full_name: the full channel name
28 * @generic_name: the output generic channel name
29 *
30 * Returns 0 on success, or a negative error code if string extraction failed.
31 **/
32int iioutils_break_up_name(const char *full_name, char **generic_name)
33{
34 char *current;
35 char *w, *r;
36 char *working, *prefix = "";
37 int i, ret;
38
39 for (i = 0; i < ARRAY_SIZE(iio_direction); i++)
40 if (!strncmp(full_name, iio_direction[i],
41 strlen(iio_direction[i]))) {
42 prefix = iio_direction[i];
43 break;
44 }
45
46 current = strdup(full_name + strlen(prefix) + 1);
47 if (!current)
48 return -ENOMEM;
49
50 working = strtok(current, "_\0");
51 if (!working) {
52 free(current);
53 return -EINVAL;
54 }
55
56 w = working;
57 r = working;
58
59 while (*r != '\0') {
60 if (!isdigit(*r)) {
61 *w = *r;
62 w++;
63 }
64
65 r++;
66 }
67 *w = '\0';
68 ret = asprintf(generic_name, "%s_%s", prefix, working);
69 free(current);
70
71 return (ret == -1) ? -ENOMEM : 0;
72}
73
74/**
75 * iioutils_get_type() - find and process _type attribute data
76 * @is_signed: output whether channel is signed
77 * @bytes: output how many bytes the channel storage occupies
78 * @bits_used: output number of valid bits of data
79 * @shift: output amount of bits to shift right data before applying bit mask
80 * @mask: output a bit mask for the raw data
81 * @be: output if data in big endian
82 * @device_dir: the IIO device directory
83 * @name: the channel name
84 * @generic_name: the channel type name
85 *
86 * Returns a value >= 0 on success, otherwise a negative error code.
87 **/
88int iioutils_get_type(unsigned *is_signed, unsigned *bytes, unsigned *bits_used,
89 unsigned *shift, uint64_t *mask, unsigned *be,
90 const char *device_dir, const char *name,
91 const char *generic_name)
92{
93 FILE *sysfsfp;
94 int ret;
95 DIR *dp;
96 char *scan_el_dir, *builtname, *builtname_generic, *filename = 0;
97 char signchar, endianchar;
98 unsigned padint;
99 const struct dirent *ent;
100
101 ret = asprintf(&scan_el_dir, FORMAT_SCAN_ELEMENTS_DIR, device_dir);
102 if (ret < 0)
103 return -ENOMEM;
104
105 ret = asprintf(&builtname, FORMAT_TYPE_FILE, name);
106 if (ret < 0) {
107 ret = -ENOMEM;
108 goto error_free_scan_el_dir;
109 }
110 ret = asprintf(&builtname_generic, FORMAT_TYPE_FILE, generic_name);
111 if (ret < 0) {
112 ret = -ENOMEM;
113 goto error_free_builtname;
114 }
115
116 dp = opendir(scan_el_dir);
117 if (!dp) {
118 ret = -errno;
119 goto error_free_builtname_generic;
120 }
121
122 ret = -ENOENT;
123 while (ent = readdir(dp), ent)
124 if ((strcmp(builtname, ent->d_name) == 0) ||
125 (strcmp(builtname_generic, ent->d_name) == 0)) {
126 ret = asprintf(&filename,
127 "%s/%s", scan_el_dir, ent->d_name);
128 if (ret < 0) {
129 ret = -ENOMEM;
130 goto error_closedir;
131 }
132
133 sysfsfp = fopen(filename, "r");
134 if (!sysfsfp) {
135 ret = -errno;
136 fprintf(stderr, "failed to open %s\n",
137 filename);
138 goto error_free_filename;
139 }
140
141 ret = fscanf(sysfsfp,
142 "%ce:%c%u/%u>>%u",
143 &endianchar,
144 &signchar,
145 bits_used,
146 &padint, shift);
147 if (ret < 0) {
148 ret = -errno;
149 fprintf(stderr,
150 "failed to pass scan type description\n");
151 goto error_close_sysfsfp;
152 } else if (ret != 5) {
153 ret = -EIO;
154 fprintf(stderr,
155 "scan type description didn't match\n");
156 goto error_close_sysfsfp;
157 }
158
159 *be = (endianchar == 'b');
160 *bytes = padint / 8;
161 if (*bits_used == 64)
162 *mask = ~0;
163 else
164 *mask = (1ULL << *bits_used) - 1;
165
166 *is_signed = (signchar == 's');
167 if (fclose(sysfsfp)) {
168 ret = -errno;
169 fprintf(stderr, "Failed to close %s\n",
170 filename);
171 goto error_free_filename;
172 }
173
174 sysfsfp = 0;
175 free(filename);
176 filename = 0;
177
178 /*
179 * Avoid having a more generic entry overwriting
180 * the settings.
181 */
182 if (strcmp(builtname, ent->d_name) == 0)
183 break;
184 }
185
186error_close_sysfsfp:
187 if (sysfsfp)
188 if (fclose(sysfsfp))
189 perror("iioutils_get_type(): Failed to close file");
190
191error_free_filename:
192 if (filename)
193 free(filename);
194
195error_closedir:
196 if (closedir(dp) == -1)
197 perror("iioutils_get_type(): Failed to close directory");
198
199error_free_builtname_generic:
200 free(builtname_generic);
201error_free_builtname:
202 free(builtname);
203error_free_scan_el_dir:
204 free(scan_el_dir);
205
206 return ret;
207}
208
209/**
210 * iioutils_get_param_float() - read a float value from a channel parameter
211 * @output: output the float value
212 * @param_name: the parameter name to read
213 * @device_dir: the IIO device directory in sysfs
214 * @name: the channel name
215 * @generic_name: the channel type name
216 *
217 * Returns a value >= 0 on success, otherwise a negative error code.
218 **/
219int iioutils_get_param_float(float *output, const char *param_name,
220 const char *device_dir, const char *name,
221 const char *generic_name)
222{
223 FILE *sysfsfp;
224 int ret;
225 DIR *dp;
226 char *builtname, *builtname_generic;
227 char *filename = NULL;
228 const struct dirent *ent;
229
230 ret = asprintf(&builtname, "%s_%s", name, param_name);
231 if (ret < 0)
232 return -ENOMEM;
233
234 ret = asprintf(&builtname_generic,
235 "%s_%s", generic_name, param_name);
236 if (ret < 0) {
237 ret = -ENOMEM;
238 goto error_free_builtname;
239 }
240
241 dp = opendir(device_dir);
242 if (!dp) {
243 ret = -errno;
244 goto error_free_builtname_generic;
245 }
246
247 ret = -ENOENT;
248 while (ent = readdir(dp), ent)
249 if ((strcmp(builtname, ent->d_name) == 0) ||
250 (strcmp(builtname_generic, ent->d_name) == 0)) {
251 ret = asprintf(&filename,
252 "%s/%s", device_dir, ent->d_name);
253 if (ret < 0) {
254 ret = -ENOMEM;
255 goto error_closedir;
256 }
257
258 sysfsfp = fopen(filename, "r");
259 if (!sysfsfp) {
260 ret = -errno;
261 goto error_free_filename;
262 }
263
264 errno = 0;
265 if (fscanf(sysfsfp, "%f", output) != 1)
266 ret = errno ? -errno : -ENODATA;
267
268 break;
269 }
270error_free_filename:
271 if (filename)
272 free(filename);
273
274error_closedir:
275 if (closedir(dp) == -1)
276 perror("iioutils_get_param_float(): Failed to close directory");
277
278error_free_builtname_generic:
279 free(builtname_generic);
280error_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
292void 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 * @ci_array: output the resulting array of iio_channel_info
310 * @counter: output the amount of array elements
311 *
312 * Returns 0 on success, otherwise a negative error code.
313 **/
314int build_channel_array(const char *device_dir,
315 struct iio_channel_info **ci_array, int *counter)
316{
317 DIR *dp;
318 FILE *sysfsfp;
319 int count = 0, i;
320 struct iio_channel_info *current;
321 int ret;
322 const struct dirent *ent;
323 char *scan_el_dir;
324 char *filename;
325
326 *counter = 0;
327 ret = asprintf(&scan_el_dir, FORMAT_SCAN_ELEMENTS_DIR, device_dir);
328 if (ret < 0)
329 return -ENOMEM;
330
331 dp = opendir(scan_el_dir);
332 if (!dp) {
333 ret = -errno;
334 goto error_free_name;
335 }
336
337 while (ent = readdir(dp), ent)
338 if (strcmp(ent->d_name + strlen(ent->d_name) - strlen("_en"),
339 "_en") == 0) {
340 ret = asprintf(&filename,
341 "%s/%s", scan_el_dir, ent->d_name);
342 if (ret < 0) {
343 ret = -ENOMEM;
344 goto error_close_dir;
345 }
346
347 sysfsfp = fopen(filename, "r");
348 if (!sysfsfp) {
349 ret = -errno;
350 free(filename);
351 goto error_close_dir;
352 }
353
354 errno = 0;
355 if (fscanf(sysfsfp, "%i", &ret) != 1) {
356 ret = errno ? -errno : -ENODATA;
357 if (fclose(sysfsfp))
358 perror("build_channel_array(): Failed to close file");
359
360 free(filename);
361 goto error_close_dir;
362 }
363 if (ret == 1)
364 (*counter)++;
365
366 if (fclose(sysfsfp)) {
367 ret = -errno;
368 free(filename);
369 goto error_close_dir;
370 }
371
372 free(filename);
373 }
374
375 *ci_array = malloc(sizeof(**ci_array) * (*counter));
376 if (!*ci_array) {
377 ret = -ENOMEM;
378 goto error_close_dir;
379 }
380
381 seekdir(dp, 0);
382 while (ent = readdir(dp), ent) {
383 if (strcmp(ent->d_name + strlen(ent->d_name) - strlen("_en"),
384 "_en") == 0) {
385 int current_enabled = 0;
386
387 current = &(*ci_array)[count++];
388 ret = asprintf(&filename,
389 "%s/%s", scan_el_dir, ent->d_name);
390 if (ret < 0) {
391 ret = -ENOMEM;
392 /* decrement count to avoid freeing name */
393 count--;
394 goto error_cleanup_array;
395 }
396
397 sysfsfp = fopen(filename, "r");
398 if (!sysfsfp) {
399 ret = -errno;
400 free(filename);
401 count--;
402 goto error_cleanup_array;
403 }
404
405 errno = 0;
406 if (fscanf(sysfsfp, "%i", ¤t_enabled) != 1) {
407 ret = errno ? -errno : -ENODATA;
408 free(filename);
409 count--;
410 goto error_cleanup_array;
411 }
412
413 if (fclose(sysfsfp)) {
414 ret = -errno;
415 free(filename);
416 count--;
417 goto error_cleanup_array;
418 }
419
420 if (!current_enabled) {
421 free(filename);
422 count--;
423 continue;
424 }
425
426 current->scale = 1.0;
427 current->offset = 0;
428 current->name = strndup(ent->d_name,
429 strlen(ent->d_name) -
430 strlen("_en"));
431 if (!current->name) {
432 free(filename);
433 ret = -ENOMEM;
434 count--;
435 goto error_cleanup_array;
436 }
437
438 /* Get the generic and specific name elements */
439 ret = iioutils_break_up_name(current->name,
440 ¤t->generic_name);
441 if (ret) {
442 free(filename);
443 free(current->name);
444 count--;
445 goto error_cleanup_array;
446 }
447
448 ret = asprintf(&filename,
449 "%s/%s_index",
450 scan_el_dir,
451 current->name);
452 if (ret < 0) {
453 free(filename);
454 ret = -ENOMEM;
455 goto error_cleanup_array;
456 }
457
458 sysfsfp = fopen(filename, "r");
459 if (!sysfsfp) {
460 ret = -errno;
461 fprintf(stderr, "failed to open %s\n",
462 filename);
463 free(filename);
464 goto error_cleanup_array;
465 }
466
467 errno = 0;
468 if (fscanf(sysfsfp, "%u", ¤t->index) != 1) {
469 ret = errno ? -errno : -ENODATA;
470 if (fclose(sysfsfp))
471 perror("build_channel_array(): Failed to close file");
472
473 free(filename);
474 goto error_cleanup_array;
475 }
476
477 if (fclose(sysfsfp)) {
478 ret = -errno;
479 free(filename);
480 goto error_cleanup_array;
481 }
482
483 free(filename);
484 /* Find the scale */
485 ret = iioutils_get_param_float(¤t->scale,
486 "scale",
487 device_dir,
488 current->name,
489 current->generic_name);
490 if ((ret < 0) && (ret != -ENOENT))
491 goto error_cleanup_array;
492
493 ret = iioutils_get_param_float(¤t->offset,
494 "offset",
495 device_dir,
496 current->name,
497 current->generic_name);
498 if ((ret < 0) && (ret != -ENOENT))
499 goto error_cleanup_array;
500
501 ret = iioutils_get_type(¤t->is_signed,
502 ¤t->bytes,
503 ¤t->bits_used,
504 ¤t->shift,
505 ¤t->mask,
506 ¤t->be,
507 device_dir,
508 current->name,
509 current->generic_name);
510 if (ret < 0)
511 goto error_cleanup_array;
512 }
513 }
514
515 if (closedir(dp) == -1) {
516 ret = -errno;
517 goto error_cleanup_array;
518 }
519
520 free(scan_el_dir);
521 /* reorder so that the array is in index order */
522 bsort_channel_array_by_index(*ci_array, *counter);
523
524 return 0;
525
526error_cleanup_array:
527 for (i = count - 1; i >= 0; i--) {
528 free((*ci_array)[i].name);
529 free((*ci_array)[i].generic_name);
530 }
531 free(*ci_array);
532 *ci_array = NULL;
533 *counter = 0;
534error_close_dir:
535 if (dp)
536 if (closedir(dp) == -1)
537 perror("build_channel_array(): Failed to close dir");
538
539error_free_name:
540 free(scan_el_dir);
541
542 return ret;
543}
544
545static int calc_digits(int num)
546{
547 int count = 0;
548
549 while (num != 0) {
550 num /= 10;
551 count++;
552 }
553
554 return count;
555}
556
557/**
558 * find_type_by_name() - function to match top level types by name
559 * @name: top level type instance name
560 * @type: the type of top level instance being searched
561 *
562 * Returns the device number of a matched IIO device on success, otherwise a
563 * negative error code.
564 * Typical types this is used for are device and trigger.
565 **/
566int find_type_by_name(const char *name, const char *type)
567{
568 const struct dirent *ent;
569 int number, numstrlen, ret;
570
571 FILE *namefp;
572 DIR *dp;
573 char thisname[IIO_MAX_NAME_LENGTH];
574 char *filename;
575
576 dp = opendir(iio_dir);
577 if (!dp) {
578 fprintf(stderr, "No industrialio devices available\n");
579 return -ENODEV;
580 }
581
582 while (ent = readdir(dp), ent) {
583 if (strcmp(ent->d_name, ".") != 0 &&
584 strcmp(ent->d_name, "..") != 0 &&
585 strlen(ent->d_name) > strlen(type) &&
586 strncmp(ent->d_name, type, strlen(type)) == 0) {
587 errno = 0;
588 ret = sscanf(ent->d_name + strlen(type), "%d", &number);
589 if (ret < 0) {
590 ret = -errno;
591 fprintf(stderr,
592 "failed to read element number\n");
593 goto error_close_dir;
594 } else if (ret != 1) {
595 ret = -EIO;
596 fprintf(stderr,
597 "failed to match element number\n");
598 goto error_close_dir;
599 }
600
601 numstrlen = calc_digits(number);
602 /* verify the next character is not a colon */
603 if (strncmp(ent->d_name + strlen(type) + numstrlen,
604 ":", 1) != 0) {
605 filename = malloc(strlen(iio_dir) + strlen(type)
606 + numstrlen + 6);
607 if (!filename) {
608 ret = -ENOMEM;
609 goto error_close_dir;
610 }
611
612 ret = sprintf(filename, "%s%s%d/name", iio_dir,
613 type, number);
614 if (ret < 0) {
615 free(filename);
616 goto error_close_dir;
617 }
618
619 namefp = fopen(filename, "r");
620 if (!namefp) {
621 free(filename);
622 continue;
623 }
624
625 free(filename);
626 errno = 0;
627 if (fscanf(namefp, "%s", thisname) != 1) {
628 ret = errno ? -errno : -ENODATA;
629 goto error_close_dir;
630 }
631
632 if (fclose(namefp)) {
633 ret = -errno;
634 goto error_close_dir;
635 }
636
637 if (strcmp(name, thisname) == 0) {
638 if (closedir(dp) == -1)
639 return -errno;
640
641 return number;
642 }
643 }
644 }
645 }
646 if (closedir(dp) == -1)
647 return -errno;
648
649 return -ENODEV;
650
651error_close_dir:
652 if (closedir(dp) == -1)
653 perror("find_type_by_name(): Failed to close directory");
654
655 return ret;
656}
657
658static int _write_sysfs_int(const char *filename, const char *basedir, int val,
659 int verify)
660{
661 int ret = 0;
662 FILE *sysfsfp;
663 int test;
664 char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
665
666 if (!temp)
667 return -ENOMEM;
668
669 ret = sprintf(temp, "%s/%s", basedir, filename);
670 if (ret < 0)
671 goto error_free;
672
673 sysfsfp = fopen(temp, "w");
674 if (!sysfsfp) {
675 ret = -errno;
676 fprintf(stderr, "failed to open %s\n", temp);
677 goto error_free;
678 }
679
680 ret = fprintf(sysfsfp, "%d", val);
681 if (ret < 0) {
682 if (fclose(sysfsfp))
683 perror("_write_sysfs_int(): Failed to close dir");
684
685 goto error_free;
686 }
687
688 if (fclose(sysfsfp)) {
689 ret = -errno;
690 goto error_free;
691 }
692
693 if (verify) {
694 sysfsfp = fopen(temp, "r");
695 if (!sysfsfp) {
696 ret = -errno;
697 fprintf(stderr, "failed to open %s\n", temp);
698 goto error_free;
699 }
700
701 if (fscanf(sysfsfp, "%d", &test) != 1) {
702 ret = errno ? -errno : -ENODATA;
703 if (fclose(sysfsfp))
704 perror("_write_sysfs_int(): Failed to close dir");
705
706 goto error_free;
707 }
708
709 if (fclose(sysfsfp)) {
710 ret = -errno;
711 goto error_free;
712 }
713
714 if (test != val) {
715 fprintf(stderr,
716 "Possible failure in int write %d to %s/%s\n",
717 val, basedir, filename);
718 ret = -1;
719 }
720 }
721
722error_free:
723 free(temp);
724 return ret;
725}
726
727/**
728 * write_sysfs_int() - write an integer value to a sysfs file
729 * @filename: name of the file to write to
730 * @basedir: the sysfs directory in which the file is to be found
731 * @val: integer value to write to file
732 *
733 * Returns a value >= 0 on success, otherwise a negative error code.
734 **/
735int write_sysfs_int(const char *filename, const char *basedir, int val)
736{
737 return _write_sysfs_int(filename, basedir, val, 0);
738}
739
740/**
741 * write_sysfs_int_and_verify() - write an integer value to a sysfs file
742 * and verify
743 * @filename: name of the file to write to
744 * @basedir: the sysfs directory in which the file is to be found
745 * @val: integer value to write to file
746 *
747 * Returns a value >= 0 on success, otherwise a negative error code.
748 **/
749int write_sysfs_int_and_verify(const char *filename, const char *basedir,
750 int val)
751{
752 return _write_sysfs_int(filename, basedir, val, 1);
753}
754
755static int _write_sysfs_string(const char *filename, const char *basedir,
756 const char *val, int verify)
757{
758 int ret = 0;
759 FILE *sysfsfp;
760 char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
761
762 if (!temp) {
763 fprintf(stderr, "Memory allocation failed\n");
764 return -ENOMEM;
765 }
766
767 ret = sprintf(temp, "%s/%s", basedir, filename);
768 if (ret < 0)
769 goto error_free;
770
771 sysfsfp = fopen(temp, "w");
772 if (!sysfsfp) {
773 ret = -errno;
774 fprintf(stderr, "Could not open %s\n", temp);
775 goto error_free;
776 }
777
778 ret = fprintf(sysfsfp, "%s", val);
779 if (ret < 0) {
780 if (fclose(sysfsfp))
781 perror("_write_sysfs_string(): Failed to close dir");
782
783 goto error_free;
784 }
785
786 if (fclose(sysfsfp)) {
787 ret = -errno;
788 goto error_free;
789 }
790
791 if (verify) {
792 sysfsfp = fopen(temp, "r");
793 if (!sysfsfp) {
794 ret = -errno;
795 fprintf(stderr, "Could not open file to verify\n");
796 goto error_free;
797 }
798
799 if (fscanf(sysfsfp, "%s", temp) != 1) {
800 ret = errno ? -errno : -ENODATA;
801 if (fclose(sysfsfp))
802 perror("_write_sysfs_string(): Failed to close dir");
803
804 goto error_free;
805 }
806
807 if (fclose(sysfsfp)) {
808 ret = -errno;
809 goto error_free;
810 }
811
812 if (strcmp(temp, val) != 0) {
813 fprintf(stderr,
814 "Possible failure in string write of %s "
815 "Should be %s written to %s/%s\n", temp, val,
816 basedir, filename);
817 ret = -1;
818 }
819 }
820
821error_free:
822 free(temp);
823
824 return ret;
825}
826
827/**
828 * write_sysfs_string_and_verify() - string write, readback and verify
829 * @filename: name of file to write to
830 * @basedir: the sysfs directory in which the file is to be found
831 * @val: the string to write
832 *
833 * Returns a value >= 0 on success, otherwise a negative error code.
834 **/
835int write_sysfs_string_and_verify(const char *filename, const char *basedir,
836 const char *val)
837{
838 return _write_sysfs_string(filename, basedir, val, 1);
839}
840
841/**
842 * write_sysfs_string() - write string to a sysfs file
843 * @filename: name of file to write to
844 * @basedir: the sysfs directory in which the file is to be found
845 * @val: the string to write
846 *
847 * Returns a value >= 0 on success, otherwise a negative error code.
848 **/
849int write_sysfs_string(const char *filename, const char *basedir,
850 const char *val)
851{
852 return _write_sysfs_string(filename, basedir, val, 0);
853}
854
855/**
856 * read_sysfs_posint() - read an integer value from file
857 * @filename: name of file to read from
858 * @basedir: the sysfs directory in which the file is to be found
859 *
860 * Returns the read integer value >= 0 on success, otherwise a negative error
861 * code.
862 **/
863int read_sysfs_posint(const char *filename, const char *basedir)
864{
865 int ret;
866 FILE *sysfsfp;
867 char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
868
869 if (!temp) {
870 fprintf(stderr, "Memory allocation failed");
871 return -ENOMEM;
872 }
873
874 ret = sprintf(temp, "%s/%s", basedir, filename);
875 if (ret < 0)
876 goto error_free;
877
878 sysfsfp = fopen(temp, "r");
879 if (!sysfsfp) {
880 ret = -errno;
881 goto error_free;
882 }
883
884 errno = 0;
885 if (fscanf(sysfsfp, "%d\n", &ret) != 1) {
886 ret = errno ? -errno : -ENODATA;
887 if (fclose(sysfsfp))
888 perror("read_sysfs_posint(): Failed to close dir");
889
890 goto error_free;
891 }
892
893 if (fclose(sysfsfp))
894 ret = -errno;
895
896error_free:
897 free(temp);
898
899 return ret;
900}
901
902/**
903 * read_sysfs_float() - read a float value from file
904 * @filename: name of file to read from
905 * @basedir: the sysfs directory in which the file is to be found
906 * @val: output the read float value
907 *
908 * Returns a value >= 0 on success, otherwise a negative error code.
909 **/
910int read_sysfs_float(const char *filename, const char *basedir, float *val)
911{
912 int ret = 0;
913 FILE *sysfsfp;
914 char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
915
916 if (!temp) {
917 fprintf(stderr, "Memory allocation failed");
918 return -ENOMEM;
919 }
920
921 ret = sprintf(temp, "%s/%s", basedir, filename);
922 if (ret < 0)
923 goto error_free;
924
925 sysfsfp = fopen(temp, "r");
926 if (!sysfsfp) {
927 ret = -errno;
928 goto error_free;
929 }
930
931 errno = 0;
932 if (fscanf(sysfsfp, "%f\n", val) != 1) {
933 ret = errno ? -errno : -ENODATA;
934 if (fclose(sysfsfp))
935 perror("read_sysfs_float(): Failed to close dir");
936
937 goto error_free;
938 }
939
940 if (fclose(sysfsfp))
941 ret = -errno;
942
943error_free:
944 free(temp);
945
946 return ret;
947}
948
949/**
950 * read_sysfs_string() - read a string from file
951 * @filename: name of file to read from
952 * @basedir: the sysfs directory in which the file is to be found
953 * @str: output the read string
954 *
955 * Returns a value >= 0 on success, otherwise a negative error code.
956 **/
957int read_sysfs_string(const char *filename, const char *basedir, char *str)
958{
959 int ret = 0;
960 FILE *sysfsfp;
961 char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
962
963 if (!temp) {
964 fprintf(stderr, "Memory allocation failed");
965 return -ENOMEM;
966 }
967
968 ret = sprintf(temp, "%s/%s", basedir, filename);
969 if (ret < 0)
970 goto error_free;
971
972 sysfsfp = fopen(temp, "r");
973 if (!sysfsfp) {
974 ret = -errno;
975 goto error_free;
976 }
977
978 errno = 0;
979 if (fscanf(sysfsfp, "%s\n", str) != 1) {
980 ret = errno ? -errno : -ENODATA;
981 if (fclose(sysfsfp))
982 perror("read_sysfs_string(): Failed to close dir");
983
984 goto error_free;
985 }
986
987 if (fclose(sysfsfp))
988 ret = -errno;
989
990error_free:
991 free(temp);
992
993 return ret;
994}