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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}
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 * @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 **/
86static 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
185error_close_sysfsfp:
186 if (sysfsfp)
187 if (fclose(sysfsfp))
188 perror("iioutils_get_type(): Failed to close file");
189
190error_free_filename:
191 if (filename)
192 free(filename);
193
194error_closedir:
195 if (closedir(dp) == -1)
196 perror("iioutils_get_type(): Failed to close directory");
197
198error_free_builtname_generic:
199 free(builtname_generic);
200error_free_builtname:
201 free(builtname);
202error_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 **/
218int 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 break;
268 }
269error_free_filename:
270 if (filename)
271 free(filename);
272
273error_closedir:
274 if (closedir(dp) == -1)
275 perror("iioutils_get_param_float(): Failed to close directory");
276
277error_free_builtname_generic:
278 free(builtname_generic);
279error_free_builtname:
280 free(builtname);
281
282 return ret;
283}
284
285/**
286 * bsort_channel_array_by_index() - sort the array in index order
287 * @ci_array: the iio_channel_info array to be sorted
288 * @cnt: the amount of array elements
289 **/
290
291void bsort_channel_array_by_index(struct iio_channel_info *ci_array, int cnt)
292{
293 struct iio_channel_info temp;
294 int x, y;
295
296 for (x = 0; x < cnt; x++)
297 for (y = 0; y < (cnt - 1); y++)
298 if (ci_array[y].index > ci_array[y + 1].index) {
299 temp = ci_array[y + 1];
300 ci_array[y + 1] = ci_array[y];
301 ci_array[y] = temp;
302 }
303}
304
305/**
306 * build_channel_array() - function to figure out what channels are present
307 * @device_dir: the IIO device directory in sysfs
308 * @buffer_idx: the IIO buffer for this channel array
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, int buffer_idx,
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, buffer_idx);
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 buffer_idx,
509 current->name,
510 current->generic_name);
511 if (ret < 0)
512 goto error_cleanup_array;
513 }
514 }
515
516 if (closedir(dp) == -1) {
517 ret = -errno;
518 goto error_cleanup_array;
519 }
520
521 free(scan_el_dir);
522 /* reorder so that the array is in index order */
523 bsort_channel_array_by_index(*ci_array, *counter);
524
525 return 0;
526
527error_cleanup_array:
528 for (i = count - 1; i >= 0; i--) {
529 free((*ci_array)[i].name);
530 free((*ci_array)[i].generic_name);
531 }
532 free(*ci_array);
533 *ci_array = NULL;
534 *counter = 0;
535error_close_dir:
536 if (dp)
537 if (closedir(dp) == -1)
538 perror("build_channel_array(): Failed to close dir");
539
540error_free_name:
541 free(scan_el_dir);
542
543 return ret;
544}
545
546static int calc_digits(int num)
547{
548 int count = 0;
549
550 while (num != 0) {
551 num /= 10;
552 count++;
553 }
554
555 return count;
556}
557
558/**
559 * find_type_by_name() - function to match top level types by name
560 * @name: top level type instance name
561 * @type: the type of top level instance being searched
562 *
563 * Returns the device number of a matched IIO device on success, otherwise a
564 * negative error code.
565 * Typical types this is used for are device and trigger.
566 **/
567int find_type_by_name(const char *name, const char *type)
568{
569 const struct dirent *ent;
570 int number, numstrlen, ret;
571
572 FILE *namefp;
573 DIR *dp;
574 char thisname[IIO_MAX_NAME_LENGTH];
575 char *filename;
576
577 dp = opendir(iio_dir);
578 if (!dp) {
579 fprintf(stderr, "No industrialio devices available\n");
580 return -ENODEV;
581 }
582
583 while (ent = readdir(dp), ent) {
584 if (strcmp(ent->d_name, ".") != 0 &&
585 strcmp(ent->d_name, "..") != 0 &&
586 strlen(ent->d_name) > strlen(type) &&
587 strncmp(ent->d_name, type, strlen(type)) == 0) {
588 errno = 0;
589 ret = sscanf(ent->d_name + strlen(type), "%d", &number);
590 if (ret < 0) {
591 ret = -errno;
592 fprintf(stderr,
593 "failed to read element number\n");
594 goto error_close_dir;
595 } else if (ret != 1) {
596 ret = -EIO;
597 fprintf(stderr,
598 "failed to match element number\n");
599 goto error_close_dir;
600 }
601
602 numstrlen = calc_digits(number);
603 /* verify the next character is not a colon */
604 if (strncmp(ent->d_name + strlen(type) + numstrlen,
605 ":", 1) != 0) {
606 filename = malloc(strlen(iio_dir) + strlen(type)
607 + numstrlen + 6);
608 if (!filename) {
609 ret = -ENOMEM;
610 goto error_close_dir;
611 }
612
613 ret = sprintf(filename, "%s%s%d/name", iio_dir,
614 type, number);
615 if (ret < 0) {
616 free(filename);
617 goto error_close_dir;
618 }
619
620 namefp = fopen(filename, "r");
621 if (!namefp) {
622 free(filename);
623 continue;
624 }
625
626 free(filename);
627 errno = 0;
628 if (fscanf(namefp, "%s", thisname) != 1) {
629 ret = errno ? -errno : -ENODATA;
630 goto error_close_dir;
631 }
632
633 if (fclose(namefp)) {
634 ret = -errno;
635 goto error_close_dir;
636 }
637
638 if (strcmp(name, thisname) == 0) {
639 if (closedir(dp) == -1)
640 return -errno;
641
642 return number;
643 }
644 }
645 }
646 }
647 if (closedir(dp) == -1)
648 return -errno;
649
650 return -ENODEV;
651
652error_close_dir:
653 if (closedir(dp) == -1)
654 perror("find_type_by_name(): Failed to close directory");
655
656 return ret;
657}
658
659static int _write_sysfs_int(const char *filename, const char *basedir, int val,
660 int verify)
661{
662 int ret = 0;
663 FILE *sysfsfp;
664 int test;
665 char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
666
667 if (!temp)
668 return -ENOMEM;
669
670 ret = sprintf(temp, "%s/%s", basedir, filename);
671 if (ret < 0)
672 goto error_free;
673
674 sysfsfp = fopen(temp, "w");
675 if (!sysfsfp) {
676 ret = -errno;
677 fprintf(stderr, "failed to open %s\n", temp);
678 goto error_free;
679 }
680
681 ret = fprintf(sysfsfp, "%d", val);
682 if (ret < 0) {
683 if (fclose(sysfsfp))
684 perror("_write_sysfs_int(): Failed to close dir");
685
686 goto error_free;
687 }
688
689 if (fclose(sysfsfp)) {
690 ret = -errno;
691 goto error_free;
692 }
693
694 if (verify) {
695 sysfsfp = fopen(temp, "r");
696 if (!sysfsfp) {
697 ret = -errno;
698 fprintf(stderr, "failed to open %s\n", temp);
699 goto error_free;
700 }
701
702 if (fscanf(sysfsfp, "%d", &test) != 1) {
703 ret = errno ? -errno : -ENODATA;
704 if (fclose(sysfsfp))
705 perror("_write_sysfs_int(): Failed to close dir");
706
707 goto error_free;
708 }
709
710 if (fclose(sysfsfp)) {
711 ret = -errno;
712 goto error_free;
713 }
714
715 if (test != val) {
716 fprintf(stderr,
717 "Possible failure in int write %d to %s/%s\n",
718 val, basedir, filename);
719 ret = -1;
720 }
721 }
722
723error_free:
724 free(temp);
725 return ret;
726}
727
728/**
729 * write_sysfs_int() - write an integer value to a sysfs file
730 * @filename: name of the file to write to
731 * @basedir: the sysfs directory in which the file is to be found
732 * @val: integer value to write to file
733 *
734 * Returns a value >= 0 on success, otherwise a negative error code.
735 **/
736int write_sysfs_int(const char *filename, const char *basedir, int val)
737{
738 return _write_sysfs_int(filename, basedir, val, 0);
739}
740
741/**
742 * write_sysfs_int_and_verify() - write an integer value to a sysfs file
743 * and verify
744 * @filename: name of the file to write to
745 * @basedir: the sysfs directory in which the file is to be found
746 * @val: integer value to write to file
747 *
748 * Returns a value >= 0 on success, otherwise a negative error code.
749 **/
750int write_sysfs_int_and_verify(const char *filename, const char *basedir,
751 int val)
752{
753 return _write_sysfs_int(filename, basedir, val, 1);
754}
755
756static int _write_sysfs_string(const char *filename, const char *basedir,
757 const char *val, int verify)
758{
759 int ret = 0;
760 FILE *sysfsfp;
761 char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
762
763 if (!temp) {
764 fprintf(stderr, "Memory allocation failed\n");
765 return -ENOMEM;
766 }
767
768 ret = sprintf(temp, "%s/%s", basedir, filename);
769 if (ret < 0)
770 goto error_free;
771
772 sysfsfp = fopen(temp, "w");
773 if (!sysfsfp) {
774 ret = -errno;
775 fprintf(stderr, "Could not open %s\n", temp);
776 goto error_free;
777 }
778
779 ret = fprintf(sysfsfp, "%s", val);
780 if (ret < 0) {
781 if (fclose(sysfsfp))
782 perror("_write_sysfs_string(): Failed to close dir");
783
784 goto error_free;
785 }
786
787 if (fclose(sysfsfp)) {
788 ret = -errno;
789 goto error_free;
790 }
791
792 if (verify) {
793 sysfsfp = fopen(temp, "r");
794 if (!sysfsfp) {
795 ret = -errno;
796 fprintf(stderr, "Could not open file to verify\n");
797 goto error_free;
798 }
799
800 if (fscanf(sysfsfp, "%s", temp) != 1) {
801 ret = errno ? -errno : -ENODATA;
802 if (fclose(sysfsfp))
803 perror("_write_sysfs_string(): Failed to close dir");
804
805 goto error_free;
806 }
807
808 if (fclose(sysfsfp)) {
809 ret = -errno;
810 goto error_free;
811 }
812
813 if (strcmp(temp, val) != 0) {
814 fprintf(stderr,
815 "Possible failure in string write of %s "
816 "Should be %s written to %s/%s\n", temp, val,
817 basedir, filename);
818 ret = -1;
819 }
820 }
821
822error_free:
823 free(temp);
824
825 return ret;
826}
827
828/**
829 * write_sysfs_string_and_verify() - string write, readback and verify
830 * @filename: name of file to write to
831 * @basedir: the sysfs directory in which the file is to be found
832 * @val: the string to write
833 *
834 * Returns a value >= 0 on success, otherwise a negative error code.
835 **/
836int write_sysfs_string_and_verify(const char *filename, const char *basedir,
837 const char *val)
838{
839 return _write_sysfs_string(filename, basedir, val, 1);
840}
841
842/**
843 * write_sysfs_string() - write string to a sysfs file
844 * @filename: name of file to write to
845 * @basedir: the sysfs directory in which the file is to be found
846 * @val: the string to write
847 *
848 * Returns a value >= 0 on success, otherwise a negative error code.
849 **/
850int write_sysfs_string(const char *filename, const char *basedir,
851 const char *val)
852{
853 return _write_sysfs_string(filename, basedir, val, 0);
854}
855
856/**
857 * read_sysfs_posint() - read an integer value from file
858 * @filename: name of file to read from
859 * @basedir: the sysfs directory in which the file is to be found
860 *
861 * Returns the read integer value >= 0 on success, otherwise a negative error
862 * code.
863 **/
864int read_sysfs_posint(const char *filename, const char *basedir)
865{
866 int ret;
867 FILE *sysfsfp;
868 char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
869
870 if (!temp) {
871 fprintf(stderr, "Memory allocation failed");
872 return -ENOMEM;
873 }
874
875 ret = sprintf(temp, "%s/%s", basedir, filename);
876 if (ret < 0)
877 goto error_free;
878
879 sysfsfp = fopen(temp, "r");
880 if (!sysfsfp) {
881 ret = -errno;
882 goto error_free;
883 }
884
885 errno = 0;
886 if (fscanf(sysfsfp, "%d\n", &ret) != 1) {
887 ret = errno ? -errno : -ENODATA;
888 if (fclose(sysfsfp))
889 perror("read_sysfs_posint(): Failed to close dir");
890
891 goto error_free;
892 }
893
894 if (fclose(sysfsfp))
895 ret = -errno;
896
897error_free:
898 free(temp);
899
900 return ret;
901}
902
903/**
904 * read_sysfs_float() - read a float value from file
905 * @filename: name of file to read from
906 * @basedir: the sysfs directory in which the file is to be found
907 * @val: output the read float value
908 *
909 * Returns a value >= 0 on success, otherwise a negative error code.
910 **/
911int read_sysfs_float(const char *filename, const char *basedir, float *val)
912{
913 int ret = 0;
914 FILE *sysfsfp;
915 char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
916
917 if (!temp) {
918 fprintf(stderr, "Memory allocation failed");
919 return -ENOMEM;
920 }
921
922 ret = sprintf(temp, "%s/%s", basedir, filename);
923 if (ret < 0)
924 goto error_free;
925
926 sysfsfp = fopen(temp, "r");
927 if (!sysfsfp) {
928 ret = -errno;
929 goto error_free;
930 }
931
932 errno = 0;
933 if (fscanf(sysfsfp, "%f\n", val) != 1) {
934 ret = errno ? -errno : -ENODATA;
935 if (fclose(sysfsfp))
936 perror("read_sysfs_float(): Failed to close dir");
937
938 goto error_free;
939 }
940
941 if (fclose(sysfsfp))
942 ret = -errno;
943
944error_free:
945 free(temp);
946
947 return ret;
948}
949
950/**
951 * read_sysfs_string() - read a string from file
952 * @filename: name of file to read from
953 * @basedir: the sysfs directory in which the file is to be found
954 * @str: output the read string
955 *
956 * Returns a value >= 0 on success, otherwise a negative error code.
957 **/
958int read_sysfs_string(const char *filename, const char *basedir, char *str)
959{
960 int ret = 0;
961 FILE *sysfsfp;
962 char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
963
964 if (!temp) {
965 fprintf(stderr, "Memory allocation failed");
966 return -ENOMEM;
967 }
968
969 ret = sprintf(temp, "%s/%s", basedir, filename);
970 if (ret < 0)
971 goto error_free;
972
973 sysfsfp = fopen(temp, "r");
974 if (!sysfsfp) {
975 ret = -errno;
976 goto error_free;
977 }
978
979 errno = 0;
980 if (fscanf(sysfsfp, "%s\n", str) != 1) {
981 ret = errno ? -errno : -ENODATA;
982 if (fclose(sysfsfp))
983 perror("read_sysfs_string(): Failed to close dir");
984
985 goto error_free;
986 }
987
988 if (fclose(sysfsfp))
989 ret = -errno;
990
991error_free:
992 free(temp);
993
994 return ret;
995}