These changes are the raw update to linux-4.4.6-rt14. Kernel sources

are taken from kernel.org, and rt patch from the rt wiki download page.

During the rebasing, the following patch collided:

Force tick interrupt and get rid of softirq magic(I70131fb85).

Collisions have been removed because its logic was found on the
source already.

Change-Id: I7f57a4081d9deaa0d9ccfc41a6c8daccdee3b769
Signed-off-by: José Pekkarinen <jose.pekkarinen@nokia.com>

1 files changed, 505 insertions, 183 deletions

diff --git a/kernel/tools/iio/iio_utils.c b/kernel/tools/iio/iio_utils.c
index 6f6452167..5eb6793f3 100644
--- a/kernel/tools/iio/iio_utils.c
+++ b/kernel/tools/iio/iio_utils.c
@@ -6,9 +6,6 @@
  * under the terms of the GNU General Public License version 2 as published by
  * the Free Software Foundation.
  */
-#ifndef _IIO_UTILS_H
-#define _IIO_UTILS_H
-
 #include <string.h>
 #include <stdlib.h>
 #include <stdio.h>
@@ -29,16 +26,17 @@ static char * const iio_direction[] = {
  * iioutils_break_up_name() - extract generic name from full channel name
  * @full_name: the full channel name
  * @generic_name: the output generic channel name
+ *
+ * Returns 0 on success, or a negative error code if string extraction failed.
  **/
-int iioutils_break_up_name(const char *full_name,
-				  char **generic_name)
+int iioutils_break_up_name(const char *full_name, char **generic_name)
 {
 	char *current;
 	char *w, *r;
 	char *working, *prefix = "";
-	int i;
+	int i, ret;
 
-	for (i = 0; i < sizeof(iio_direction) / sizeof(iio_direction[0]); i++)
+	for (i = 0; i < ARRAY_SIZE(iio_direction); i++)
 		if (!strncmp(full_name, iio_direction[i],
 			     strlen(iio_direction[i]))) {
 			prefix = iio_direction[i];
@@ -46,7 +44,14 @@ int iioutils_break_up_name(const char *full_name,
 		}
 
 	current = strdup(full_name + strlen(prefix) + 1);
+	if (!current)
+		return -ENOMEM;
+
 	working = strtok(current, "_\0");
+	if (!working) {
+		free(current);
+		return -EINVAL;
+	}
 
 	w = working;
 	r = working;
@@ -56,34 +61,34 @@ int iioutils_break_up_name(const char *full_name,
 			*w = *r;
 			w++;
 		}
+
 		r++;
 	}
 	*w = '\0';
-	asprintf(generic_name, "%s_%s", prefix, working);
+	ret = asprintf(generic_name, "%s_%s", prefix, working);
 	free(current);
 
-	return 0;
+	return (ret == -1) ? -ENOMEM : 0;
 }
 
 /**
  * iioutils_get_type() - find and process _type attribute data
  * @is_signed: output whether channel is signed
  * @bytes: output how many bytes the channel storage occupies
+ * @bits_used: output number of valid bits of data
+ * @shift: output amount of bits to shift right data before applying bit mask
  * @mask: output a bit mask for the raw data
- * @be: big endian
- * @device_dir: the iio device directory
+ * @be: output if data in big endian
+ * @device_dir: the IIO device directory
  * @name: the channel name
  * @generic_name: the channel type name
+ *
+ * Returns a value >= 0 on success, otherwise a negative error code.
  **/
-int iioutils_get_type(unsigned *is_signed,
-			     unsigned *bytes,
-			     unsigned *bits_used,
-			     unsigned *shift,
-			     uint64_t *mask,
-			     unsigned *be,
-			     const char *device_dir,
-			     const char *name,
-			     const char *generic_name)
+int iioutils_get_type(unsigned *is_signed, unsigned *bytes, unsigned *bits_used,
+		      unsigned *shift, uint64_t *mask, unsigned *be,
+		      const char *device_dir, const char *name,
+		      const char *generic_name)
 {
 	FILE *sysfsfp;
 	int ret;
@@ -94,10 +99,9 @@ int iioutils_get_type(unsigned *is_signed,
 	const struct dirent *ent;
 
 	ret = asprintf(&scan_el_dir, FORMAT_SCAN_ELEMENTS_DIR, device_dir);
-	if (ret < 0) {
-		ret = -ENOMEM;
-		goto error_ret;
-	}
+	if (ret < 0)
+		return -ENOMEM;
+
 	ret = asprintf(&builtname, FORMAT_TYPE_FILE, name);
 	if (ret < 0) {
 		ret = -ENOMEM;
@@ -110,11 +114,13 @@ int iioutils_get_type(unsigned *is_signed,
 	}
 
 	dp = opendir(scan_el_dir);
-	if (dp == NULL) {
+	if (!dp) {
 		ret = -errno;
 		goto error_free_builtname_generic;
 	}
-	while (ent = readdir(dp), ent != NULL)
+
+	ret = -ENOENT;
+	while (ent = readdir(dp), ent)
 		/*
 		 * Do we allow devices to override a generic name with
 		 * a specific one?
@@ -127,10 +133,12 @@ int iioutils_get_type(unsigned *is_signed,
 				ret = -ENOMEM;
 				goto error_closedir;
 			}
+
 			sysfsfp = fopen(filename, "r");
-			if (sysfsfp == NULL) {
-				printf("failed to open %s\n", filename);
+			if (!sysfsfp) {
 				ret = -errno;
+				fprintf(stderr, "failed to open %s\n",
+					filename);
 				goto error_free_filename;
 			}
 
@@ -141,49 +149,73 @@ int iioutils_get_type(unsigned *is_signed,
 				     bits_used,
 				     &padint, shift);
 			if (ret < 0) {
-				printf("failed to pass scan type description\n");
 				ret = -errno;
+				fprintf(stderr,
+					"failed to pass scan type description\n");
+				goto error_close_sysfsfp;
+			} else if (ret != 5) {
+				ret = -EIO;
+				fprintf(stderr,
+					"scan type description didn't match\n");
 				goto error_close_sysfsfp;
 			}
+
 			*be = (endianchar == 'b');
 			*bytes = padint / 8;
 			if (*bits_used == 64)
 				*mask = ~0;
 			else
-				*mask = (1 << *bits_used) - 1;
-			if (signchar == 's')
-				*is_signed = 1;
-			else
-				*is_signed = 0;
-			fclose(sysfsfp);
-			free(filename);
+				*mask = (1ULL << *bits_used) - 1;
+
+			*is_signed = (signchar == 's');
+			if (fclose(sysfsfp)) {
+				ret = -errno;
+				fprintf(stderr, "Failed to close %s\n",
+					filename);
+				goto error_free_filename;
+			}
 
-			filename = 0;
 			sysfsfp = 0;
+			free(filename);
+			filename = 0;
 		}
+
 error_close_sysfsfp:
 	if (sysfsfp)
-		fclose(sysfsfp);
+		if (fclose(sysfsfp))
+			perror("iioutils_get_type(): Failed to close file");
+
 error_free_filename:
 	if (filename)
 		free(filename);
+
 error_closedir:
-	closedir(dp);
+	if (closedir(dp) == -1)
+		perror("iioutils_get_type(): Failed to close directory");
+
 error_free_builtname_generic:
 	free(builtname_generic);
 error_free_builtname:
 	free(builtname);
 error_free_scan_el_dir:
 	free(scan_el_dir);
-error_ret:
+
 	return ret;
 }
 
-int iioutils_get_param_float(float *output,
-				    const char *param_name,
-				    const char *device_dir,
-				    const char *name,
-				    const char *generic_name)
+/**
+ * iioutils_get_param_float() - read a float value from a channel parameter
+ * @output: output the float value
+ * @param_name: the parameter name to read
+ * @device_dir: the IIO device directory in sysfs
+ * @name: the channel name
+ * @generic_name: the channel type name
+ *
+ * Returns a value >= 0 on success, otherwise a negative error code.
+ **/
+int iioutils_get_param_float(float *output, const char *param_name,
+			     const char *device_dir, const char *name,
+			     const char *generic_name)
 {
 	FILE *sysfsfp;
 	int ret;
@@ -193,22 +225,24 @@ int iioutils_get_param_float(float *output,
 	const struct dirent *ent;
 
 	ret = asprintf(&builtname, "%s_%s", name, param_name);
-	if (ret < 0) {
-		ret = -ENOMEM;
-		goto error_ret;
-	}
+	if (ret < 0)
+		return -ENOMEM;
+
 	ret = asprintf(&builtname_generic,
 		       "%s_%s", generic_name, param_name);
 	if (ret < 0) {
 		ret = -ENOMEM;
 		goto error_free_builtname;
 	}
+
 	dp = opendir(device_dir);
-	if (dp == NULL) {
+	if (!dp) {
 		ret = -errno;
 		goto error_free_builtname_generic;
 	}
-	while (ent = readdir(dp), ent != NULL)
+
+	ret = -ENOENT;
+	while (ent = readdir(dp), ent)
 		if ((strcmp(builtname, ent->d_name) == 0) ||
 		    (strcmp(builtname_generic, ent->d_name) == 0)) {
 			ret = asprintf(&filename,
@@ -217,60 +251,69 @@ int iioutils_get_param_float(float *output,
 				ret = -ENOMEM;
 				goto error_closedir;
 			}
+
 			sysfsfp = fopen(filename, "r");
 			if (!sysfsfp) {
 				ret = -errno;
 				goto error_free_filename;
 			}
-			fscanf(sysfsfp, "%f", output);
+
+			errno = 0;
+			if (fscanf(sysfsfp, "%f", output) != 1)
+				ret = errno ? -errno : -ENODATA;
+
 			break;
 		}
 error_free_filename:
 	if (filename)
 		free(filename);
+
 error_closedir:
-	closedir(dp);
+	if (closedir(dp) == -1)
+		perror("iioutils_get_param_float(): Failed to close directory");
+
 error_free_builtname_generic:
 	free(builtname_generic);
 error_free_builtname:
 	free(builtname);
-error_ret:
+
 	return ret;
 }
 
 /**
- * bsort_channel_array_by_index() - reorder so that the array is in index order
- *
+ * bsort_channel_array_by_index() - sort the array in index order
+ * @ci_array: the iio_channel_info array to be sorted
+ * @cnt: the amount of array elements
  **/
 
-void bsort_channel_array_by_index(struct iio_channel_info **ci_array,
-					 int cnt)
+void bsort_channel_array_by_index(struct iio_channel_info *ci_array, int cnt)
 {
-
 	struct iio_channel_info temp;
 	int x, y;
 
 	for (x = 0; x < cnt; x++)
 		for (y = 0; y < (cnt - 1); y++)
-			if ((*ci_array)[y].index > (*ci_array)[y+1].index) {
-				temp = (*ci_array)[y + 1];
-				(*ci_array)[y + 1] = (*ci_array)[y];
-				(*ci_array)[y] = temp;
+			if (ci_array[y].index > ci_array[y + 1].index) {
+				temp = ci_array[y + 1];
+				ci_array[y + 1] = ci_array[y];
+				ci_array[y] = temp;
 			}
 }
 
 /**
  * build_channel_array() - function to figure out what channels are present
  * @device_dir: the IIO device directory in sysfs
- * @
+ * @ci_array: output the resulting array of iio_channel_info
+ * @counter: output the amount of array elements
+ *
+ * Returns 0 on success, otherwise a negative error code.
  **/
 int build_channel_array(const char *device_dir,
-			      struct iio_channel_info **ci_array,
-			      int *counter)
+			struct iio_channel_info **ci_array, int *counter)
 {
 	DIR *dp;
 	FILE *sysfsfp;
-	int count, i;
+	int count = 0, i;
 	struct iio_channel_info *current;
 	int ret;
 	const struct dirent *ent;
@@ -279,16 +322,16 @@ int build_channel_array(const char *device_dir,
 
 	*counter = 0;
 	ret = asprintf(&scan_el_dir, FORMAT_SCAN_ELEMENTS_DIR, device_dir);
-	if (ret < 0) {
-		ret = -ENOMEM;
-		goto error_ret;
-	}
+	if (ret < 0)
+		return -ENOMEM;
+
 	dp = opendir(scan_el_dir);
-	if (dp == NULL) {
+	if (!dp) {
 		ret = -errno;
 		goto error_free_name;
 	}
-	while (ent = readdir(dp), ent != NULL)
+
+	while (ent = readdir(dp), ent)
 		if (strcmp(ent->d_name + strlen(ent->d_name) - strlen("_en"),
 			   "_en") == 0) {
 			ret = asprintf(&filename,
@@ -297,26 +340,43 @@ int build_channel_array(const char *device_dir,
 				ret = -ENOMEM;
 				goto error_close_dir;
 			}
+
 			sysfsfp = fopen(filename, "r");
-			if (sysfsfp == NULL) {
+			if (!sysfsfp) {
 				ret = -errno;
 				free(filename);
 				goto error_close_dir;
 			}
-			fscanf(sysfsfp, "%i", &ret);
+
+			errno = 0;
+			if (fscanf(sysfsfp, "%i", &ret) != 1) {
+				ret = errno ? -errno : -ENODATA;
+				if (fclose(sysfsfp))
+					perror("build_channel_array(): Failed to close file");
+
+				free(filename);
+				goto error_close_dir;
+			}
 			if (ret == 1)
 				(*counter)++;
-			fclose(sysfsfp);
+
+			if (fclose(sysfsfp)) {
+				ret = -errno;
+				free(filename);
+				goto error_close_dir;
+			}
+
 			free(filename);
 		}
+
 	*ci_array = malloc(sizeof(**ci_array) * (*counter));
-	if (*ci_array == NULL) {
+	if (!*ci_array) {
 		ret = -ENOMEM;
 		goto error_close_dir;
 	}
+
 	seekdir(dp, 0);
-	count = 0;
-	while (ent = readdir(dp), ent != NULL) {
+	while (ent = readdir(dp), ent) {
 		if (strcmp(ent->d_name + strlen(ent->d_name) - strlen("_en"),
 			   "_en") == 0) {
 			int current_enabled = 0;
@@ -330,14 +390,29 @@ int build_channel_array(const char *device_dir,
 				count--;
 				goto error_cleanup_array;
 			}
+
 			sysfsfp = fopen(filename, "r");
-			if (sysfsfp == NULL) {
+			if (!sysfsfp) {
+				ret = -errno;
 				free(filename);
+				count--;
+				goto error_cleanup_array;
+			}
+
+			errno = 0;
+			if (fscanf(sysfsfp, "%i", &current_enabled) != 1) {
+				ret = errno ? -errno : -ENODATA;
+				free(filename);
+				count--;
+				goto error_cleanup_array;
+			}
+
+			if (fclose(sysfsfp)) {
 				ret = -errno;
+				free(filename);
+				count--;
 				goto error_cleanup_array;
 			}
-			fscanf(sysfsfp, "%i", &current_enabled);
-			fclose(sysfsfp);
 
 			if (!current_enabled) {
 				free(filename);
@@ -350,18 +425,23 @@ int build_channel_array(const char *device_dir,
 			current->name = strndup(ent->d_name,
 						strlen(ent->d_name) -
 						strlen("_en"));
-			if (current->name == NULL) {
+			if (!current->name) {
 				free(filename);
 				ret = -ENOMEM;
+				count--;
 				goto error_cleanup_array;
 			}
+
 			/* Get the generic and specific name elements */
 			ret = iioutils_break_up_name(current->name,
 						     &current->generic_name);
 			if (ret) {
 				free(filename);
+				free(current->name);
+				count--;
 				goto error_cleanup_array;
 			}
+
 			ret = asprintf(&filename,
 				       "%s/%s_index",
 				       scan_el_dir,
@@ -371,9 +451,32 @@ int build_channel_array(const char *device_dir,
 				ret = -ENOMEM;
 				goto error_cleanup_array;
 			}
+
 			sysfsfp = fopen(filename, "r");
-			fscanf(sysfsfp, "%u", &current->index);
-			fclose(sysfsfp);
+			if (!sysfsfp) {
+				ret = -errno;
+				fprintf(stderr, "failed to open %s\n",
+					filename);
+				free(filename);
+				goto error_cleanup_array;
+			}
+
+			errno = 0;
+			if (fscanf(sysfsfp, "%u", &current->index) != 1) {
+				ret = errno ? -errno : -ENODATA;
+				if (fclose(sysfsfp))
+					perror("build_channel_array(): Failed to close file");
+
+				free(filename);
+				goto error_cleanup_array;
+			}
+
+			if (fclose(sysfsfp)) {
+				ret = -errno;
+				free(filename);
+				goto error_cleanup_array;
+			}
+
 			free(filename);
 			/* Find the scale */
 			ret = iioutils_get_param_float(&current->scale,
@@ -381,15 +484,17 @@ int build_channel_array(const char *device_dir,
 						       device_dir,
 						       current->name,
 						       current->generic_name);
-			if (ret < 0)
+			if ((ret < 0) && (ret != -ENOENT))
 				goto error_cleanup_array;
+
 			ret = iioutils_get_param_float(&current->offset,
 						       "offset",
 						       device_dir,
 						       current->name,
 						       current->generic_name);
-			if (ret < 0)
+			if ((ret < 0) && (ret != -ENOENT))
 				goto error_cleanup_array;
+
 			ret = iioutils_get_type(&current->is_signed,
 						&current->bytes,
 						&current->bits_used,
@@ -399,182 +504,317 @@ int build_channel_array(const char *device_dir,
 						device_dir,
 						current->name,
 						current->generic_name);
+			if (ret < 0)
+				goto error_cleanup_array;
 		}
 	}
 
-	closedir(dp);
+	if (closedir(dp) == -1) {
+		ret = -errno;
+		goto error_cleanup_array;
+	}
+
+	free(scan_el_dir);
 	/* reorder so that the array is in index order */
-	bsort_channel_array_by_index(ci_array, *counter);
+	bsort_channel_array_by_index(*ci_array, *counter);
 
 	return 0;
 
 error_cleanup_array:
-	for (i = count - 1;  i >= 0; i--)
+	for (i = count - 1;  i >= 0; i--) {
 		free((*ci_array)[i].name);
+		free((*ci_array)[i].generic_name);
+	}
 	free(*ci_array);
+	*ci_array = NULL;
+	*counter = 0;
 error_close_dir:
-	closedir(dp);
+	if (dp)
+		if (closedir(dp) == -1)
+			perror("build_channel_array(): Failed to close dir");
+
 error_free_name:
 	free(scan_el_dir);
-error_ret:
+
 	return ret;
 }
 
+static int calc_digits(int num)
+{
+	int count = 0;
+
+	while (num != 0) {
+		num /= 10;
+		count++;
+	}
+
+	return count;
+}
+
 /**
  * find_type_by_name() - function to match top level types by name
  * @name: top level type instance name
- * @type: the type of top level instance being sort
+ * @type: the type of top level instance being searched
  *
+ * Returns the device number of a matched IIO device on success, otherwise a
+ * negative error code.
  * Typical types this is used for are device and trigger.
  **/
 int find_type_by_name(const char *name, const char *type)
 {
 	const struct dirent *ent;
-	int number, numstrlen;
+	int number, numstrlen, ret;
 
-	FILE *nameFile;
+	FILE *namefp;
 	DIR *dp;
 	char thisname[IIO_MAX_NAME_LENGTH];
 	char *filename;
 
 	dp = opendir(iio_dir);
-	if (dp == NULL) {
-		printf("No industrialio devices available\n");
+	if (!dp) {
+		fprintf(stderr, "No industrialio devices available\n");
 		return -ENODEV;
 	}
 
-	while (ent = readdir(dp), ent != NULL) {
+	while (ent = readdir(dp), ent) {
 		if (strcmp(ent->d_name, ".") != 0 &&
-			strcmp(ent->d_name, "..") != 0 &&
-			strlen(ent->d_name) > strlen(type) &&
-			strncmp(ent->d_name, type, strlen(type)) == 0) {
-			numstrlen = sscanf(ent->d_name + strlen(type),
-					   "%d",
-					   &number);
+		    strcmp(ent->d_name, "..") != 0 &&
+		    strlen(ent->d_name) > strlen(type) &&
+		    strncmp(ent->d_name, type, strlen(type)) == 0) {
+			errno = 0;
+			ret = sscanf(ent->d_name + strlen(type), "%d", &number);
+			if (ret < 0) {
+				ret = -errno;
+				fprintf(stderr,
+					"failed to read element number\n");
+				goto error_close_dir;
+			} else if (ret != 1) {
+				ret = -EIO;
+				fprintf(stderr,
+					"failed to match element number\n");
+				goto error_close_dir;
+			}
+
+			numstrlen = calc_digits(number);
 			/* verify the next character is not a colon */
 			if (strncmp(ent->d_name + strlen(type) + numstrlen,
-					":",
-					1) != 0) {
-				filename = malloc(strlen(iio_dir)
-						+ strlen(type)
-						+ numstrlen
-						+ 6);
-				if (filename == NULL) {
-					closedir(dp);
-					return -ENOMEM;
+			    ":", 1) != 0) {
+				filename = malloc(strlen(iio_dir) + strlen(type)
+						  + numstrlen + 6);
+				if (!filename) {
+					ret = -ENOMEM;
+					goto error_close_dir;
 				}
-				sprintf(filename, "%s%s%d/name",
-					iio_dir,
-					type,
-					number);
-				nameFile = fopen(filename, "r");
-				if (!nameFile) {
+
+				ret = sprintf(filename, "%s%s%d/name", iio_dir,
+					      type, number);
+				if (ret < 0) {
+					free(filename);
+					goto error_close_dir;
+				}
+
+				namefp = fopen(filename, "r");
+				if (!namefp) {
 					free(filename);
 					continue;
 				}
+
 				free(filename);
-				fscanf(nameFile, "%s", thisname);
-				fclose(nameFile);
+				errno = 0;
+				if (fscanf(namefp, "%s", thisname) != 1) {
+					ret = errno ? -errno : -ENODATA;
+					goto error_close_dir;
+				}
+
+				if (fclose(namefp)) {
+					ret = -errno;
+					goto error_close_dir;
+				}
+
 				if (strcmp(name, thisname) == 0) {
-					closedir(dp);
+					if (closedir(dp) == -1)
+						return -errno;
+
 					return number;
 				}
 			}
 		}
 	}
-	closedir(dp);
+	if (closedir(dp) == -1)
+		return -errno;
+
 	return -ENODEV;
+
+error_close_dir:
+	if (closedir(dp) == -1)
+		perror("find_type_by_name(): Failed to close directory");
+
+	return ret;
 }
 
-int _write_sysfs_int(char *filename, char *basedir, int val, int verify)
+static int _write_sysfs_int(const char *filename, const char *basedir, int val,
+			    int verify)
 {
 	int ret = 0;
 	FILE *sysfsfp;
 	int test;
 	char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
 
-	if (temp == NULL)
+	if (!temp)
 		return -ENOMEM;
-	sprintf(temp, "%s/%s", basedir, filename);
+
+	ret = sprintf(temp, "%s/%s", basedir, filename);
+	if (ret < 0)
+		goto error_free;
+
 	sysfsfp = fopen(temp, "w");
-	if (sysfsfp == NULL) {
-		printf("failed to open %s\n", temp);
+	if (!sysfsfp) {
 		ret = -errno;
+		fprintf(stderr, "failed to open %s\n", temp);
+		goto error_free;
+	}
+
+	ret = fprintf(sysfsfp, "%d", val);
+	if (ret < 0) {
+		if (fclose(sysfsfp))
+			perror("_write_sysfs_int(): Failed to close dir");
+
 		goto error_free;
 	}
-	fprintf(sysfsfp, "%d", val);
-	fclose(sysfsfp);
+
+	if (fclose(sysfsfp)) {
+		ret = -errno;
+		goto error_free;
+	}
+
 	if (verify) {
 		sysfsfp = fopen(temp, "r");
-		if (sysfsfp == NULL) {
-			printf("failed to open %s\n", temp);
+		if (!sysfsfp) {
+			ret = -errno;
+			fprintf(stderr, "failed to open %s\n", temp);
+			goto error_free;
+		}
+
+		if (fscanf(sysfsfp, "%d", &test) != 1) {
+			ret = errno ? -errno : -ENODATA;
+			if (fclose(sysfsfp))
+				perror("_write_sysfs_int(): Failed to close dir");
+
+			goto error_free;
+		}
+
+		if (fclose(sysfsfp)) {
 			ret = -errno;
 			goto error_free;
 		}
-		fscanf(sysfsfp, "%d", &test);
-		fclose(sysfsfp);
+
 		if (test != val) {
-			printf("Possible failure in int write %d to %s%s\n",
-				val,
-				basedir,
-				filename);
+			fprintf(stderr,
+				"Possible failure in int write %d to %s/%s\n",
+				val, basedir, filename);
 			ret = -1;
 		}
 	}
+
 error_free:
 	free(temp);
 	return ret;
 }
 
-int write_sysfs_int(char *filename, char *basedir, int val)
+/**
+ * write_sysfs_int() - write an integer value to a sysfs file
+ * @filename: name of the file to write to
+ * @basedir: the sysfs directory in which the file is to be found
+ * @val: integer value to write to file
+ *
+ * Returns a value >= 0 on success, otherwise a negative error code.
+ **/
+int write_sysfs_int(const char *filename, const char *basedir, int val)
 {
 	return _write_sysfs_int(filename, basedir, val, 0);
 }
 
-int write_sysfs_int_and_verify(char *filename, char *basedir, int val)
+/**
+ * write_sysfs_int_and_verify() - write an integer value to a sysfs file
+ *				  and verify
+ * @filename: name of the file to write to
+ * @basedir: the sysfs directory in which the file is to be found
+ * @val: integer value to write to file
+ *
+ * Returns a value >= 0 on success, otherwise a negative error code.
+ **/
+int write_sysfs_int_and_verify(const char *filename, const char *basedir,
+			       int val)
 {
 	return _write_sysfs_int(filename, basedir, val, 1);
 }
 
-int _write_sysfs_string(char *filename, char *basedir, char *val, int verify)
+static int _write_sysfs_string(const char *filename, const char *basedir,
+			       const char *val, int verify)
 {
 	int ret = 0;
 	FILE  *sysfsfp;
 	char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
 
-	if (temp == NULL) {
-		printf("Memory allocation failed\n");
+	if (!temp) {
+		fprintf(stderr, "Memory allocation failed\n");
 		return -ENOMEM;
 	}
-	sprintf(temp, "%s/%s", basedir, filename);
+
+	ret = sprintf(temp, "%s/%s", basedir, filename);
+	if (ret < 0)
+		goto error_free;
+
 	sysfsfp = fopen(temp, "w");
-	if (sysfsfp == NULL) {
-		printf("Could not open %s\n", temp);
+	if (!sysfsfp) {
+		ret = -errno;
+		fprintf(stderr, "Could not open %s\n", temp);
+		goto error_free;
+	}
+
+	ret = fprintf(sysfsfp, "%s", val);
+	if (ret < 0) {
+		if (fclose(sysfsfp))
+			perror("_write_sysfs_string(): Failed to close dir");
+
+		goto error_free;
+	}
+
+	if (fclose(sysfsfp)) {
 		ret = -errno;
 		goto error_free;
 	}
-	fprintf(sysfsfp, "%s", val);
-	fclose(sysfsfp);
+
 	if (verify) {
 		sysfsfp = fopen(temp, "r");
-		if (sysfsfp == NULL) {
-			printf("could not open file to verify\n");
+		if (!sysfsfp) {
 			ret = -errno;
+			fprintf(stderr, "Could not open file to verify\n");
 			goto error_free;
 		}
-		fscanf(sysfsfp, "%s", temp);
-		fclose(sysfsfp);
+
+		if (fscanf(sysfsfp, "%s", temp) != 1) {
+			ret = errno ? -errno : -ENODATA;
+			if (fclose(sysfsfp))
+				perror("_write_sysfs_string(): Failed to close dir");
+
+			goto error_free;
+		}
+
+		if (fclose(sysfsfp)) {
+			ret = -errno;
+			goto error_free;
+		}
+
 		if (strcmp(temp, val) != 0) {
-			printf("Possible failure in string write of %s "
-				"Should be %s "
-				"written to %s\%s\n",
-				temp,
-				val,
-				basedir,
-				filename);
+			fprintf(stderr,
+				"Possible failure in string write of %s "
+				"Should be %s written to %s/%s\n", temp, val,
+				basedir, filename);
 			ret = -1;
 		}
 	}
+
 error_free:
 	free(temp);
 
@@ -586,84 +826,166 @@ error_free:
  * @filename: name of file to write to
  * @basedir: the sysfs directory in which the file is to be found
  * @val: the string to write
+ *
+ * Returns a value >= 0 on success, otherwise a negative error code.
  **/
-int write_sysfs_string_and_verify(char *filename, char *basedir, char *val)
+int write_sysfs_string_and_verify(const char *filename, const char *basedir,
+				  const char *val)
 {
 	return _write_sysfs_string(filename, basedir, val, 1);
 }
 
-int write_sysfs_string(char *filename, char *basedir, char *val)
+/**
+ * write_sysfs_string() - write string to a sysfs file
+ * @filename: name of file to write to
+ * @basedir: the sysfs directory in which the file is to be found
+ * @val: the string to write
+ *
+ * Returns a value >= 0 on success, otherwise a negative error code.
+ **/
+int write_sysfs_string(const char *filename, const char *basedir,
+		       const char *val)
 {
 	return _write_sysfs_string(filename, basedir, val, 0);
 }
 
-int read_sysfs_posint(char *filename, char *basedir)
+/**
+ * read_sysfs_posint() - read an integer value from file
+ * @filename: name of file to read from
+ * @basedir: the sysfs directory in which the file is to be found
+ *
+ * Returns the read integer value >= 0 on success, otherwise a negative error
+ * code.
+ **/
+int read_sysfs_posint(const char *filename, const char *basedir)
 {
 	int ret;
 	FILE  *sysfsfp;
 	char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
 
-	if (temp == NULL) {
-		printf("Memory allocation failed");
+	if (!temp) {
+		fprintf(stderr, "Memory allocation failed");
 		return -ENOMEM;
 	}
-	sprintf(temp, "%s/%s", basedir, filename);
+
+	ret = sprintf(temp, "%s/%s", basedir, filename);
+	if (ret < 0)
+		goto error_free;
+
 	sysfsfp = fopen(temp, "r");
-	if (sysfsfp == NULL) {
+	if (!sysfsfp) {
 		ret = -errno;
 		goto error_free;
 	}
-	fscanf(sysfsfp, "%d\n", &ret);
-	fclose(sysfsfp);
+
+	errno = 0;
+	if (fscanf(sysfsfp, "%d\n", &ret) != 1) {
+		ret = errno ? -errno : -ENODATA;
+		if (fclose(sysfsfp))
+			perror("read_sysfs_posint(): Failed to close dir");
+
+		goto error_free;
+	}
+
+	if (fclose(sysfsfp))
+		ret = -errno;
+
 error_free:
 	free(temp);
+
 	return ret;
 }
 
-int read_sysfs_float(char *filename, char *basedir, float *val)
+/**
+ * read_sysfs_float() - read a float value from file
+ * @filename: name of file to read from
+ * @basedir: the sysfs directory in which the file is to be found
+ * @val: output the read float value
+ *
+ * Returns a value >= 0 on success, otherwise a negative error code.
+ **/
+int read_sysfs_float(const char *filename, const char *basedir, float *val)
 {
 	int ret = 0;
 	FILE  *sysfsfp;
 	char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
 
-	if (temp == NULL) {
-		printf("Memory allocation failed");
+	if (!temp) {
+		fprintf(stderr, "Memory allocation failed");
 		return -ENOMEM;
 	}
-	sprintf(temp, "%s/%s", basedir, filename);
+
+	ret = sprintf(temp, "%s/%s", basedir, filename);
+	if (ret < 0)
+		goto error_free;
+
 	sysfsfp = fopen(temp, "r");
-	if (sysfsfp == NULL) {
+	if (!sysfsfp) {
 		ret = -errno;
 		goto error_free;
 	}
-	fscanf(sysfsfp, "%f\n", val);
-	fclose(sysfsfp);
+
+	errno = 0;
+	if (fscanf(sysfsfp, "%f\n", val) != 1) {
+		ret = errno ? -errno : -ENODATA;
+		if (fclose(sysfsfp))
+			perror("read_sysfs_float(): Failed to close dir");
+
+		goto error_free;
+	}
+
+	if (fclose(sysfsfp))
+		ret = -errno;
+
 error_free:
 	free(temp);
+
 	return ret;
 }
 
+/**
+ * read_sysfs_string() - read a string from file
+ * @filename: name of file to read from
+ * @basedir: the sysfs directory in which the file is to be found
+ * @str: output the read string
+ *
+ * Returns a value >= 0 on success, otherwise a negative error code.
+ **/
 int read_sysfs_string(const char *filename, const char *basedir, char *str)
 {
 	int ret = 0;
 	FILE  *sysfsfp;
 	char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
 
-	if (temp == NULL) {
-		printf("Memory allocation failed");
+	if (!temp) {
+		fprintf(stderr, "Memory allocation failed");
 		return -ENOMEM;
 	}
-	sprintf(temp, "%s/%s", basedir, filename);
+
+	ret = sprintf(temp, "%s/%s", basedir, filename);
+	if (ret < 0)
+		goto error_free;
+
 	sysfsfp = fopen(temp, "r");
-	if (sysfsfp == NULL) {
+	if (!sysfsfp) {
 		ret = -errno;
 		goto error_free;
 	}
-	fscanf(sysfsfp, "%s\n", str);
-	fclose(sysfsfp);
+
+	errno = 0;
+	if (fscanf(sysfsfp, "%s\n", str) != 1) {
+		ret = errno ? -errno : -ENODATA;
+		if (fclose(sysfsfp))
+			perror("read_sysfs_string(): Failed to close dir");
+
+		goto error_free;
+	}
+
+	if (fclose(sysfsfp))
+		ret = -errno;
+
 error_free:
 	free(temp);
+
 	return ret;
 }
-
-#endif /* _IIO_UTILS_H */