| /* |
| * Copyright (c) 2016-present, Facebook, Inc. |
| * All rights reserved. |
| * |
| * This source code is licensed under both the BSD-style license (found in the |
| * LICENSE file in the root directory of this source tree) and the GPLv2 (found |
| * in the COPYING file in the root directory of this source tree). |
| */ |
| |
| /* DO_XXH should be 32 or 64 for xxh32 and xxh64 respectively */ |
| #define DO_XXH 0 |
| /* DO_CRC should be 0 or 1 */ |
| #define DO_CRC 0 |
| /* Buffer size */ |
| #define BUFFER_SIZE 4096 |
| |
| #include <linux/kernel.h> |
| #include <linux/module.h> |
| #include <linux/fs.h> |
| #include <linux/uaccess.h> |
| |
| #if DO_XXH |
| #include <linux/xxhash.h> |
| #endif |
| |
| #if DO_CRC |
| #include <linux/crc32.h> |
| #endif |
| |
| /* Device name to pass to register_chrdev(). */ |
| #define DEVICE_NAME "xxhash_test" |
| |
| /* Dynamically allocated device major number */ |
| static int device_major; |
| |
| /* |
| * We reuse the same hash state, and thus can hash only one |
| * file at a time. |
| */ |
| static bool device_is_open; |
| |
| static uint64_t total_length; |
| |
| |
| #if (DO_XXH == 32) |
| |
| #define xxh_state xxh32_state |
| #define xxh_reset xxh32_reset |
| #define xxh_update xxh32_update |
| #define xxh_digest xxh32_digest |
| #define XXH_FORMAT "XXH32 = 0x%x" |
| |
| #elif (DO_XXH == 64) |
| |
| #define xxh_state xxh64_state |
| #define xxh_reset xxh64_reset |
| #define xxh_update xxh64_update |
| #define xxh_digest xxh64_digest |
| #define XXH_FORMAT "XXH64 = 0x%llx" |
| |
| #elif DO_XXH |
| |
| #error "Invalid value of DO_XXH" |
| |
| #endif |
| |
| #if DO_XXH |
| |
| /* XXH state */ |
| static struct xxh_state state; |
| |
| #endif /* DO_XXH */ |
| |
| #if DO_CRC |
| |
| static uint32_t crc; |
| |
| #endif /* DO_CRC */ |
| |
| /* |
| * Input buffer used to put data coming from userspace. |
| */ |
| static uint8_t buffer_in[BUFFER_SIZE]; |
| |
| static int xxhash_test_open(struct inode *i, struct file *f) |
| { |
| if (device_is_open) |
| return -EBUSY; |
| |
| device_is_open = true; |
| |
| total_length = 0; |
| #if DO_XXH |
| xxh_reset(&state, 0); |
| #endif |
| #if DO_CRC |
| crc = 0xFFFFFFFF; |
| #endif |
| |
| printk(KERN_INFO DEVICE_NAME ": opened\n"); |
| return 0; |
| } |
| |
| static int xxhash_test_release(struct inode *i, struct file *f) |
| { |
| device_is_open = false; |
| |
| printk(KERN_INFO DEVICE_NAME ": total_len = %llu\n", total_length); |
| #if DO_XXH |
| printk(KERN_INFO DEVICE_NAME ": " XXH_FORMAT "\n", xxh_digest(&state)); |
| #endif |
| #if DO_CRC |
| printk(KERN_INFO DEVICE_NAME ": CRC32 = 0x%08x\n", ~crc); |
| #endif |
| printk(KERN_INFO DEVICE_NAME ": closed\n"); |
| return 0; |
| } |
| |
| /* |
| * Hash the data given to us from userspace. |
| */ |
| static ssize_t xxhash_test_write(struct file *file, const char __user *buf, |
| size_t size, loff_t *pos) |
| { |
| size_t remaining = size; |
| |
| while (remaining > 0) { |
| #if DO_XXH |
| int ret; |
| #endif |
| size_t const copy_size = min(remaining, sizeof(buffer_in)); |
| |
| if (copy_from_user(buffer_in, buf, copy_size)) |
| return -EFAULT; |
| buf += copy_size; |
| remaining -= copy_size; |
| total_length += copy_size; |
| #if DO_XXH |
| if ((ret = xxh_update(&state, buffer_in, copy_size))) { |
| printk(KERN_INFO DEVICE_NAME ": xxh failure."); |
| return ret; |
| } |
| #endif |
| #if DO_CRC |
| crc = crc32(crc, buffer_in, copy_size); |
| #endif |
| } |
| return size; |
| } |
| /* register the character device. */ |
| static int __init xxhash_test_init(void) |
| { |
| static const struct file_operations fileops = { |
| .owner = THIS_MODULE, |
| .open = &xxhash_test_open, |
| .release = &xxhash_test_release, |
| .write = &xxhash_test_write |
| }; |
| |
| device_major = register_chrdev(0, DEVICE_NAME, &fileops); |
| if (device_major < 0) { |
| return device_major; |
| } |
| |
| printk(KERN_INFO DEVICE_NAME ": module loaded\n"); |
| printk(KERN_INFO DEVICE_NAME ": Create a device node with " |
| "'mknod " DEVICE_NAME " c %d 0' and write data " |
| "to it.\n", device_major); |
| return 0; |
| } |
| |
| static void __exit xxhash_test_exit(void) |
| { |
| unregister_chrdev(device_major, DEVICE_NAME); |
| printk(KERN_INFO DEVICE_NAME ": module unloaded\n"); |
| } |
| |
| module_init(xxhash_test_init); |
| module_exit(xxhash_test_exit); |
| |
| MODULE_DESCRIPTION("XXHash tester"); |
| MODULE_VERSION("1.0"); |
| |
| |
| MODULE_LICENSE("Dual BSD/GPL"); |