tools/iio/iio_utils:fix memory leak

1. fopen sysfs without fclose.
2. asprintf filename without free.
3. if asprintf return error,do not need to free the buffer.

Signed-off-by: Yulong Zhang <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Jonathan Cameron <[e-mail]>

tools/iio/iio_utils.c

···
 			if (fscanf(sysfsfp, "%f", output) != 1)
 				ret = errno ? -errno : -ENODATA;
 
+			fclose(sysfsfp);
 			break;
 		}
 error_free_filename:
···
 			}
 
 			sysfsfp = fopen(filename, "r");
+			free(filename);
 			if (!sysfsfp) {
 				ret = -errno;
-				free(filename);
 				goto error_close_dir;
 			}
 
···
 				if (fclose(sysfsfp))
 					perror("build_channel_array(): Failed to close file");
 
-				free(filename);
 				goto error_close_dir;
 			}
 			if (ret == 1)
···
 
 			if (fclose(sysfsfp)) {
 				ret = -errno;
-				free(filename);
 				goto error_close_dir;
 			}
 
-			free(filename);
 		}
 
 	*ci_array = malloc(sizeof(**ci_array) * (*counter));
···
 			}
 
 			sysfsfp = fopen(filename, "r");
+			free(filename);
 			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;
 			}
 
 			if (!current_enabled) {
-				free(filename);
 				count--;
 				continue;
 			}
···
 						strlen(ent->d_name) -
 						strlen("_en"));
 			if (!current->name) {
-				free(filename);
 				ret = -ENOMEM;
 				count--;
 				goto error_cleanup_array;
···
 			ret = iioutils_break_up_name(current->name,
 						     &current->generic_name);
 			if (ret) {
-				free(filename);
 				free(current->name);
 				count--;
 				goto error_cleanup_array;
···
 				       scan_el_dir,
 				       current->name);
 			if (ret < 0) {
-				free(filename);
 				ret = -ENOMEM;
 				goto error_cleanup_array;
 			}
 
 			sysfsfp = fopen(filename, "r");
+			free(filename);
 			if (!sysfsfp) {
 				ret = -errno;
-				fprintf(stderr, "failed to open %s\n",
-					filename);
-				free(filename);
+				fprintf(stderr, "failed to open %s/%s_index\n",
+					scan_el_dir, current->name);
 				goto error_cleanup_array;
 			}
 
···
 				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,
 						       "scale",