]> git.karo-electronics.de Git - karo-tx-linux.git/blobdiff - tools/iio/iio_utils.c
Merge tag 'sirf-iobrg2regmap-for-4.2' of git://git.kernel.org/pub/scm/linux/kernel...
[karo-tx-linux.git] / tools / iio / iio_utils.c
index 6f6452167b670a833ecc50b6eb136743a9fafd05..ec9ab7f9ae4c50e5ac77bedbdff5e6a144eafe78 100644 (file)
@@ -29,6 +29,8 @@ 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)
@@ -36,7 +38,7 @@ int iioutils_break_up_name(const char *full_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++)
                if (!strncmp(full_name, iio_direction[i],
@@ -46,7 +48,14 @@ 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;
@@ -59,21 +68,25 @@ int iioutils_break_up_name(const char *full_name,
                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,
@@ -94,10 +107,9 @@ 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;
@@ -114,6 +126,7 @@ int iioutils_get_type(unsigned *is_signed,
                ret = -errno;
                goto error_free_builtname_generic;
        }
+       ret = -ENOENT;
        while (ent = readdir(dp), ent != NULL)
                /*
                 * Do we allow devices to override a generic name with
@@ -129,8 +142,8 @@ int iioutils_get_type(unsigned *is_signed,
                        }
                        sysfsfp = fopen(filename, "r");
                        if (sysfsfp == NULL) {
-                               printf("failed to open %s\n", filename);
                                ret = -errno;
+                               printf("failed to open %s\n", filename);
                                goto error_free_filename;
                        }
 
@@ -141,8 +154,12 @@ int iioutils_get_type(unsigned *is_signed,
                                     bits_used,
                                     &padint, shift);
                        if (ret < 0) {
-                               printf("failed to pass scan type description\n");
                                ret = -errno;
+                               printf("failed to pass scan type description\n");
+                               goto error_close_sysfsfp;
+                       } else if (ret != 5) {
+                               ret = -EIO;
+                               printf("scan type description didn't match\n");
                                goto error_close_sysfsfp;
                        }
                        *be = (endianchar == 'b');
@@ -151,34 +168,50 @@ int iioutils_get_type(unsigned *is_signed,
                                *mask = ~0;
                        else
                                *mask = (1 << *bits_used) - 1;
-                       if (signchar == 's')
-                               *is_signed = 1;
-                       else
-                               *is_signed = 0;
-                       fclose(sysfsfp);
+                       *is_signed = (signchar == 's');
+                       if (fclose(sysfsfp)) {
+                               ret = -errno;
+                               printf("Failed to close %s\n", filename);
+                               goto error_free_filename;
+                       }
+
+                       sysfsfp = 0;
                        free(filename);
 
                        filename = 0;
-                       sysfsfp = 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;
 }
 
+/**
+ * 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,
@@ -193,10 +226,9 @@ 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) {
@@ -208,6 +240,7 @@ int iioutils_get_param_float(float *output,
                ret = -errno;
                goto error_free_builtname_generic;
        }
+       ret = -ENOENT;
        while (ent = readdir(dp), ent != NULL)
                if ((strcmp(builtname, ent->d_name) == 0) ||
                    (strcmp(builtname_generic, ent->d_name) == 0)) {
@@ -222,25 +255,31 @@ int iioutils_get_param_float(float *output,
                                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,
@@ -262,7 +301,10 @@ void bsort_channel_array_by_index(struct iio_channel_info **ci_array,
 /**
  * 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,
@@ -270,7 +312,7 @@ int build_channel_array(const char *device_dir,
 {
        DIR *dp;
        FILE *sysfsfp;
-       int count, i;
+       int count = 0, i;
        struct iio_channel_info *current;
        int ret;
        const struct dirent *ent;
@@ -279,10 +321,9 @@ 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) {
                ret = -errno;
@@ -303,10 +344,24 @@ int build_channel_array(const char *device_dir,
                                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));
@@ -315,7 +370,6 @@ int build_channel_array(const char *device_dir,
                goto error_close_dir;
        }
        seekdir(dp, 0);
-       count = 0;
        while (ent = readdir(dp), ent != NULL) {
                if (strcmp(ent->d_name + strlen(ent->d_name) - strlen("_en"),
                           "_en") == 0) {
@@ -332,12 +386,25 @@ int build_channel_array(const char *device_dir,
                        }
                        sysfsfp = fopen(filename, "r");
                        if (sysfsfp == NULL) {
+                               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);
@@ -353,6 +420,7 @@ int build_channel_array(const char *device_dir,
                        if (current->name == NULL) {
                                free(filename);
                                ret = -ENOMEM;
+                               count--;
                                goto error_cleanup_array;
                        }
                        /* Get the generic and specific name elements */
@@ -360,6 +428,8 @@ int build_channel_array(const char *device_dir,
                                                     &current->generic_name);
                        if (ret) {
                                free(filename);
+                               free(current->name);
+                               count--;
                                goto error_cleanup_array;
                        }
                        ret = asprintf(&filename,
@@ -372,8 +442,29 @@ int build_channel_array(const char *device_dir,
                                goto error_cleanup_array;
                        }
                        sysfsfp = fopen(filename, "r");
-                       fscanf(sysfsfp, "%u", &current->index);
-                       fclose(sysfsfp);
+                       if (sysfsfp == NULL) {
+                               ret = -errno;
+                               printf("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,
@@ -399,38 +490,64 @@ 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);
 
        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);
 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;
 }
 
+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;
        DIR *dp;
@@ -448,9 +565,19 @@ int find_type_by_name(const char *name, const char *type)
                        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);
+                       errno = 0;
+                       ret = sscanf(ent->d_name + strlen(type), "%d", &number);
+                       if (ret < 0) {
+                               ret = -errno;
+                               printf("failed to read element number\n");
+                               goto error_close_dir;
+                       } else if (ret != 1) {
+                               ret = -EIO;
+                               printf("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,
                                        ":",
@@ -460,33 +587,55 @@ int find_type_by_name(const char *name, const char *type)
                                                + numstrlen
                                                + 6);
                                if (filename == NULL) {
-                                       closedir(dp);
-                                       return -ENOMEM;
+                                       ret = -ENOMEM;
+                                       goto error_close_dir;
                                }
-                               sprintf(filename, "%s%s%d/name",
-                                       iio_dir,
-                                       type,
-                                       number);
+
+                               ret = sprintf(filename, "%s%s%d/name", iio_dir,
+                                             type, number);
+                               if (ret < 0) {
+                                       free(filename);
+                                       goto error_close_dir;
+                               }
+
                                nameFile = fopen(filename, "r");
                                if (!nameFile) {
                                        free(filename);
                                        continue;
                                }
                                free(filename);
-                               fscanf(nameFile, "%s", thisname);
-                               fclose(nameFile);
+                               errno = 0;
+                               if (fscanf(nameFile, "%s", thisname) != 1) {
+                                       ret = errno ? -errno : -ENODATA;
+                                       goto error_close_dir;
+                               }
+
+                               if (fclose(nameFile)) {
+                                       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;
@@ -495,24 +644,49 @@ int _write_sysfs_int(char *filename, char *basedir, int val, int verify)
 
        if (temp == NULL)
                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) {
+               ret = -errno;
                printf("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;
+       }
+
+       if (fclose(sysfsfp)) {
                ret = -errno;
                goto error_free;
        }
-       fprintf(sysfsfp, "%d", val);
-       fclose(sysfsfp);
+
        if (verify) {
                sysfsfp = fopen(temp, "r");
                if (sysfsfp == NULL) {
+                       ret = -errno;
                        printf("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,
@@ -526,17 +700,36 @@ error_free:
        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;
@@ -546,24 +739,49 @@ int _write_sysfs_string(char *filename, char *basedir, char *val, int verify)
                printf("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) {
+               ret = -errno;
                printf("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) {
+                       ret = -errno;
                        printf("could not open file to verify\n");
+                       goto error_free;
+               }
+               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;
                }
-               fscanf(sysfsfp, "%s", temp);
-               fclose(sysfsfp);
+
                if (strcmp(temp, val) != 0) {
                        printf("Possible failure in string write of %s "
                                "Should be %s "
@@ -586,18 +804,38 @@ 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;
@@ -607,20 +845,41 @@ int read_sysfs_posint(char *filename, char *basedir)
                printf("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) {
                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;
@@ -630,19 +889,40 @@ int read_sysfs_float(char *filename, char *basedir, float *val)
                printf("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) {
                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;
@@ -653,14 +933,27 @@ int read_sysfs_string(const char *filename, const char *basedir, char *str)
                printf("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) {
                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;