1229159Sadrian/* 2229159Sadrian * XZ decoder tester 3229159Sadrian * 4229159Sadrian * Author: Lasse Collin <lasse.collin@tukaani.org> 5229159Sadrian * 6229159Sadrian * This file has been put into the public domain. 7229159Sadrian * You can do whatever you want with this file. 8229159Sadrian */ 9229159Sadrian 10229159Sadrian#include <linux/kernel.h> 11229159Sadrian#include <linux/module.h> 12229159Sadrian#include <linux/fs.h> 13229159Sadrian#include <linux/uaccess.h> 14229159Sadrian#include <linux/crc32.h> 15229159Sadrian#include <linux/xz.h> 16229159Sadrian 17229159Sadrian/* Maximum supported dictionary size */ 18229159Sadrian#define DICT_MAX (1 << 20) 19229159Sadrian 20229159Sadrian/* Device name to pass to register_chrdev(). */ 21229159Sadrian#define DEVICE_NAME "xz_dec_test" 22229159Sadrian 23229159Sadrian/* Dynamically allocated device major number */ 24229159Sadrianstatic int device_major; 25229159Sadrian 26229159Sadrian/* 27229159Sadrian * We reuse the same decoder state, and thus can decode only one 28229159Sadrian * file at a time. 29229159Sadrian */ 30229159Sadrianstatic bool device_is_open; 31229159Sadrian 32229159Sadrian/* XZ decoder state */ 33229159Sadrianstatic struct xz_dec *state; 34229159Sadrian 35229159Sadrian/* 36229159Sadrian * Return value of xz_dec_run(). We need to avoid calling xz_dec_run() after 37229159Sadrian * it has returned XZ_STREAM_END, so we make this static. 38229159Sadrian */ 39229159Sadrianstatic enum xz_ret ret; 40229159Sadrian 41229159Sadrian/* 42229159Sadrian * Input and output buffers. The input buffer is used as a temporary safe 43229159Sadrian * place for the data coming from the userspace. 44229159Sadrian */ 45229159Sadrianstatic uint8_t buffer_in[1024]; 46229159Sadrianstatic uint8_t buffer_out[1024]; 47229159Sadrian 48229159Sadrian/* 49229159Sadrian * Structure to pass the input and output buffers to the XZ decoder. 50229159Sadrian * A few of the fields are never modified so we initialize them here. 51229159Sadrian */ 52229159Sadrianstatic struct xz_buf buffers = { 53229159Sadrian .in = buffer_in, 54229159Sadrian .out = buffer_out, 55229159Sadrian .out_size = sizeof(buffer_out) 56229159Sadrian}; 57229159Sadrian 58229159Sadrian/* 59229159Sadrian * CRC32 of uncompressed data. This is used to give the user a simple way 60229159Sadrian * to check that the decoder produces correct output. 61229159Sadrian */ 62229159Sadrianstatic uint32_t crc; 63229159Sadrian 64229159Sadrianstatic int xz_dec_test_open(struct inode *i, struct file *f) 65229159Sadrian{ 66229159Sadrian if (device_is_open) 67229159Sadrian return -EBUSY; 68229159Sadrian 69229159Sadrian device_is_open = true; 70229159Sadrian 71229159Sadrian xz_dec_reset(state); 72229159Sadrian ret = XZ_OK; 73229159Sadrian crc = 0xFFFFFFFF; 74229159Sadrian 75229159Sadrian buffers.in_pos = 0; 76229159Sadrian buffers.in_size = 0; 77229159Sadrian buffers.out_pos = 0; 78229159Sadrian 79229159Sadrian printk(KERN_INFO DEVICE_NAME ": opened\n"); 80229159Sadrian return 0; 81229159Sadrian} 82229159Sadrian 83229159Sadrianstatic int xz_dec_test_release(struct inode *i, struct file *f) 84229159Sadrian{ 85229159Sadrian device_is_open = false; 86229159Sadrian 87229159Sadrian if (ret == XZ_OK) 88229159Sadrian printk(KERN_INFO DEVICE_NAME ": input was truncated\n"); 89229159Sadrian 90229159Sadrian printk(KERN_INFO DEVICE_NAME ": closed\n"); 91229159Sadrian return 0; 92229159Sadrian} 93229159Sadrian 94229159Sadrian/* 95229159Sadrian * Decode the data given to us from the userspace. CRC32 of the uncompressed 96229159Sadrian * data is calculated and is printed at the end of successful decoding. The 97229159Sadrian * uncompressed data isn't stored anywhere for further use. 98229159Sadrian * 99229159Sadrian * The .xz file must have exactly one Stream and no Stream Padding. The data 100229159Sadrian * after the first Stream is considered to be garbage. 101229159Sadrian */ 102229159Sadrianstatic ssize_t xz_dec_test_write(struct file *file, const char __user *buf, 103229159Sadrian size_t size, loff_t *pos) 104229159Sadrian{ 105229159Sadrian size_t remaining; 106229159Sadrian 107229159Sadrian if (ret != XZ_OK) { 108229159Sadrian if (size > 0) 109229159Sadrian printk(KERN_INFO DEVICE_NAME ": %zu bytes of " 110229159Sadrian "garbage at the end of the file\n", 111229159Sadrian size); 112229159Sadrian 113229159Sadrian return -ENOSPC; 114229159Sadrian } 115229159Sadrian 116229159Sadrian printk(KERN_INFO DEVICE_NAME ": decoding %zu bytes of input\n", 117229159Sadrian size); 118229159Sadrian 119229159Sadrian remaining = size; 120229159Sadrian while ((remaining > 0 || buffers.out_pos == buffers.out_size) 121229159Sadrian && ret == XZ_OK) { 122229159Sadrian if (buffers.in_pos == buffers.in_size) { 123229159Sadrian buffers.in_pos = 0; 124229159Sadrian buffers.in_size = min(remaining, sizeof(buffer_in)); 125229159Sadrian if (copy_from_user(buffer_in, buf, buffers.in_size)) 126229159Sadrian return -EFAULT; 127229159Sadrian 128229159Sadrian buf += buffers.in_size; 129229159Sadrian remaining -= buffers.in_size; 130229159Sadrian } 131229159Sadrian 132229159Sadrian buffers.out_pos = 0; 133229159Sadrian ret = xz_dec_run(state, &buffers); 134229159Sadrian crc = crc32(crc, buffer_out, buffers.out_pos); 135229159Sadrian } 136229159Sadrian 137229159Sadrian switch (ret) { 138229159Sadrian case XZ_OK: 139229159Sadrian printk(KERN_INFO DEVICE_NAME ": XZ_OK\n"); 140229159Sadrian return size; 141229159Sadrian 142229159Sadrian case XZ_STREAM_END: 143229159Sadrian printk(KERN_INFO DEVICE_NAME ": XZ_STREAM_END, " 144229159Sadrian "CRC32 = 0x%08X\n", ~crc); 145229159Sadrian return size - remaining - (buffers.in_size - buffers.in_pos); 146229159Sadrian 147229159Sadrian case XZ_MEMLIMIT_ERROR: 148229159Sadrian printk(KERN_INFO DEVICE_NAME ": XZ_MEMLIMIT_ERROR\n"); 149229159Sadrian break; 150229159Sadrian 151229159Sadrian case XZ_FORMAT_ERROR: 152229159Sadrian printk(KERN_INFO DEVICE_NAME ": XZ_FORMAT_ERROR\n"); 153229159Sadrian break; 154229159Sadrian 155229159Sadrian case XZ_OPTIONS_ERROR: 156229159Sadrian printk(KERN_INFO DEVICE_NAME ": XZ_OPTIONS_ERROR\n"); 157229159Sadrian break; 158229159Sadrian 159229159Sadrian case XZ_DATA_ERROR: 160229159Sadrian printk(KERN_INFO DEVICE_NAME ": XZ_DATA_ERROR\n"); 161229159Sadrian break; 162229159Sadrian 163229159Sadrian case XZ_BUF_ERROR: 164229159Sadrian printk(KERN_INFO DEVICE_NAME ": XZ_BUF_ERROR\n"); 165229159Sadrian break; 166229159Sadrian 167229159Sadrian default: 168229159Sadrian printk(KERN_INFO DEVICE_NAME ": Bug detected!\n"); 169229159Sadrian break; 170229159Sadrian } 171229159Sadrian 172229159Sadrian return -EIO; 173229159Sadrian} 174229159Sadrian 175229159Sadrian/* Allocate the XZ decoder state and register the character device. */ 176229159Sadrianstatic int __init xz_dec_test_init(void) 177229159Sadrian{ 178229159Sadrian static const struct file_operations fileops = { 179229159Sadrian .owner = THIS_MODULE, 180229159Sadrian .open = &xz_dec_test_open, 181229159Sadrian .release = &xz_dec_test_release, 182229159Sadrian .write = &xz_dec_test_write 183229159Sadrian }; 184229159Sadrian 185229159Sadrian state = xz_dec_init(XZ_PREALLOC, DICT_MAX); 186229159Sadrian if (state == NULL) 187229159Sadrian return -ENOMEM; 188229159Sadrian 189229159Sadrian device_major = register_chrdev(0, DEVICE_NAME, &fileops); 190229159Sadrian if (device_major < 0) { 191229159Sadrian xz_dec_end(state); 192229159Sadrian return device_major; 193229159Sadrian } 194229159Sadrian 195229159Sadrian printk(KERN_INFO DEVICE_NAME ": module loaded\n"); 196229159Sadrian printk(KERN_INFO DEVICE_NAME ": Create a device node with " 197229159Sadrian "'mknod " DEVICE_NAME " c %d 0' and write .xz files " 198229159Sadrian "to it.\n", device_major); 199229159Sadrian return 0; 200229159Sadrian} 201229159Sadrian 202229159Sadrianstatic void __exit xz_dec_test_exit(void) 203229159Sadrian{ 204229159Sadrian unregister_chrdev(device_major, DEVICE_NAME); 205229159Sadrian xz_dec_end(state); 206229159Sadrian printk(KERN_INFO DEVICE_NAME ": module unloaded\n"); 207229159Sadrian} 208229159Sadrian 209229159Sadrianmodule_init(xz_dec_test_init); 210229159Sadrianmodule_exit(xz_dec_test_exit); 211229159Sadrian 212229159SadrianMODULE_DESCRIPTION("XZ decompressor tester"); 213229159SadrianMODULE_VERSION("1.0"); 214229159SadrianMODULE_AUTHOR("Lasse Collin <lasse.collin@tukaani.org>"); 215229159Sadrian 216229159Sadrian/* 217229159Sadrian * This code is in the public domain, but in Linux it's simplest to just 218229159Sadrian * say it's GPL and consider the authors as the copyright holders. 219229159Sadrian */ 220229159SadrianMODULE_LICENSE("GPL"); 221