1 files changed, 220 insertions, 0 deletions

diff --git a/lib/xz/xz_dec_test.c b/lib/xz/xz_dec_test.c
new file mode 100644
index 000000000000..da28a19d6c98
--- /dev/null
+++ b/lib/xz/xz_dec_test.c
@@ -0,0 +1,220 @@
+/*
+ * XZ decoder tester
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/uaccess.h>
+#include <linux/crc32.h>
+#include <linux/xz.h>
+
+/* Maximum supported dictionary size */
+#define DICT_MAX (1 << 20)
+
+/* Device name to pass to register_chrdev(). */
+#define DEVICE_NAME "xz_dec_test"
+
+/* Dynamically allocated device major number */
+static int device_major;
+
+/*
+ * We reuse the same decoder state, and thus can decode only one
+ * file at a time.
+ */
+static bool device_is_open;
+
+/* XZ decoder state */
+static struct xz_dec *state;
+
+/*
+ * Return value of xz_dec_run(). We need to avoid calling xz_dec_run() after
+ * it has returned XZ_STREAM_END, so we make this static.
+ */
+static enum xz_ret ret;
+
+/*
+ * Input and output buffers. The input buffer is used as a temporary safe
+ * place for the data coming from the userspace.
+ */
+static uint8_t buffer_in[1024];
+static uint8_t buffer_out[1024];
+
+/*
+ * Structure to pass the input and output buffers to the XZ decoder.
+ * A few of the fields are never modified so we initialize them here.
+ */
+static struct xz_buf buffers = {
+        .in = buffer_in,
+        .out = buffer_out,
+        .out_size = sizeof(buffer_out)
+};
+
+/*
+ * CRC32 of uncompressed data. This is used to give the user a simple way
+ * to check that the decoder produces correct output.
+ */
+static uint32_t crc;
+
+static int xz_dec_test_open(struct inode *i, struct file *f)
+{
+        if (device_is_open)
+                return -EBUSY;
+
+        device_is_open = true;
+
+        xz_dec_reset(state);
+        ret = XZ_OK;
+        crc = 0xFFFFFFFF;
+
+        buffers.in_pos = 0;
+        buffers.in_size = 0;
+        buffers.out_pos = 0;
+
+        printk(KERN_INFO DEVICE_NAME ": opened\n");
+        return 0;
+}
+
+static int xz_dec_test_release(struct inode *i, struct file *f)
+{
+        device_is_open = false;
+
+        if (ret == XZ_OK)
+                printk(KERN_INFO DEVICE_NAME ": input was truncated\n");
+
+        printk(KERN_INFO DEVICE_NAME ": closed\n");
+        return 0;
+}
+
+/*
+ * Decode the data given to us from the userspace. CRC32 of the uncompressed
+ * data is calculated and is printed at the end of successful decoding. The
+ * uncompressed data isn't stored anywhere for further use.
+ *
+ * The .xz file must have exactly one Stream and no Stream Padding. The data
+ * after the first Stream is considered to be garbage.
+ */
+static ssize_t xz_dec_test_write(struct file *file, const char __user *buf,
+                                 size_t size, loff_t *pos)
+{
+        size_t remaining;
+
+        if (ret != XZ_OK) {
+                if (size > 0)
+                        printk(KERN_INFO DEVICE_NAME ": %zu bytes of "
+                                        "garbage at the end of the file\n",
+                                        size);
+
+                return -ENOSPC;
+        }
+
+        printk(KERN_INFO DEVICE_NAME ": decoding %zu bytes of input\n",
+                        size);
+
+        remaining = size;
+        while ((remaining > 0 || buffers.out_pos == buffers.out_size)
+                        && ret == XZ_OK) {
+                if (buffers.in_pos == buffers.in_size) {
+                        buffers.in_pos = 0;
+                        buffers.in_size = min(remaining, sizeof(buffer_in));
+                        if (copy_from_user(buffer_in, buf, buffers.in_size))
+                                return -EFAULT;
+
+                        buf += buffers.in_size;
+                        remaining -= buffers.in_size;
+                }
+
+                buffers.out_pos = 0;
+                ret = xz_dec_run(state, &buffers);
+                crc = crc32(crc, buffer_out, buffers.out_pos);
+        }
+
+        switch (ret) {
+        case XZ_OK:
+                printk(KERN_INFO DEVICE_NAME ": XZ_OK\n");
+                return size;
+
+        case XZ_STREAM_END:
+                printk(KERN_INFO DEVICE_NAME ": XZ_STREAM_END, "
+                                "CRC32 = 0x%08X\n", ~crc);
+                return size - remaining - (buffers.in_size - buffers.in_pos);
+
+        case XZ_MEMLIMIT_ERROR:
+                printk(KERN_INFO DEVICE_NAME ": XZ_MEMLIMIT_ERROR\n");
+                break;
+
+        case XZ_FORMAT_ERROR:
+                printk(KERN_INFO DEVICE_NAME ": XZ_FORMAT_ERROR\n");
+                break;
+
+        case XZ_OPTIONS_ERROR:
+                printk(KERN_INFO DEVICE_NAME ": XZ_OPTIONS_ERROR\n");
+                break;
+
+        case XZ_DATA_ERROR:
+                printk(KERN_INFO DEVICE_NAME ": XZ_DATA_ERROR\n");
+                break;
+
+        case XZ_BUF_ERROR:
+                printk(KERN_INFO DEVICE_NAME ": XZ_BUF_ERROR\n");
+                break;
+
+        default:
+                printk(KERN_INFO DEVICE_NAME ": Bug detected!\n");
+                break;
+        }
+
+        return -EIO;
+}
+
+/* Allocate the XZ decoder state and register the character device. */
+static int __init xz_dec_test_init(void)
+{
+        static const struct file_operations fileops = {
+                .owner = THIS_MODULE,
+                .open = &xz_dec_test_open,
+                .release = &xz_dec_test_release,
+                .write = &xz_dec_test_write
+        };
+
+        state = xz_dec_init(XZ_PREALLOC, DICT_MAX);
+        if (state == NULL)
+                return -ENOMEM;
+
+        device_major = register_chrdev(0, DEVICE_NAME, &fileops);
+        if (device_major < 0) {
+                xz_dec_end(state);
+                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 .xz files "
+                        "to it.\n", device_major);
+        return 0;
+}
+
+static void __exit xz_dec_test_exit(void)
+{
+        unregister_chrdev(device_major, DEVICE_NAME);
+        xz_dec_end(state);
+        printk(KERN_INFO DEVICE_NAME ": module unloaded\n");
+}
+
+module_init(xz_dec_test_init);
+module_exit(xz_dec_test_exit);
+
+MODULE_DESCRIPTION("XZ decompressor tester");
+MODULE_VERSION("1.0");
+MODULE_AUTHOR("Lasse Collin <lasse.collin@tukaani.org>");
+
+/*
+ * This code is in the public domain, but in Linux it's simplest to just
+ * say it's GPL and consider the authors as the copyright holders.
+ */
+MODULE_LICENSE("GPL");