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/*

 * ramdisk.c - Multiple ramdisk driver - gzip-loading version - v. 0.8 beta.

 *

 * (C) Chad Page, Theodore Ts'o, et. al, 1995.

 *

 * This ramdisk is designed to have filesystems created on it and mounted

 * just like a regular floppy disk.

 *

 * It also does something suggested by Linus: use the buffer cache as the

 * ramdisk data.  This makes it possible to dynamically allocate the ramdisk

 * buffer - with some consequences I have to deal with as I write this.

 *

 * This code is based on the original ramdisk.c, written mostly by

 * Theodore Ts'o (TYT) in 1991.  The code was largely rewritten by

 * Chad Page to use the buffer cache to store the ramdisk data in

 * 1995; Theodore then took over the driver again, and cleaned it up

 * for inclusion in the mainline kernel.

 *

 * The original CRAMDISK code was written by Richard Lyons, and

 * adapted by Chad Page to use the new ramdisk interface.  Theodore

 * Ts'o rewrote it so that both the compressed ramdisk loader and the

 * kernel decompressor uses the same inflate.c codebase.  The ramdisk

 * loader now also loads into a dynamic (buffer cache based) ramdisk,

 * not the old static ramdisk.  Support for the old static ramdisk has

 * been completely removed.

 *

 * Loadable module support added by Tom Dyas.

 *

 * Further cleanups by Chad Page (page0588@sundance.sjsu.edu):

 *      Cosmetic changes in #ifdef MODULE, code movement, etc...

 *      When the ramdisk is rmmod'ed, free the protected buffers

 *      Default ramdisk size changed to 2.88MB

 *

 *  Added initrd: Werner Almesberger & Hans Lermen, Feb '96

 *

 * 4/25/96 : Made ramdisk size a parameter (default is now 4MB)

 *              - Chad Page

 */

#include <linux/config.h>

#include <linux/sched.h>

#include <linux/minix_fs.h>

#include <linux/ext2_fs.h>

#include <linux/fs.h>

#include <linux/kernel.h>

#include <linux/string.h>

#include <linux/mm.h>

#include <linux/mman.h>

#include <linux/malloc.h>

#include <linux/ioctl.h>

#include <linux/fd.h>

#include <linux/module.h>

#include <asm/system.h>

#include <asm/segment.h>

extern void wait_for_keypress(void);

/*

 * 35 has been officially registered as the RAMDISK major number, but

 * so is the original MAJOR number of 1.  We're using 1 in

 * include/linux/major.h for now

 */

#define MAJOR_NR RAMDISK_MAJOR

#include <linux/blk.h>

/* The ramdisk size is now a parameter */

#define NUM_RAMDISKS 16         /* This cannot be overridden (yet) */ 

#ifndef MODULE

/* We don't have to load ramdisks or gunzip them in a module... */

#define RD_LOADER

#define BUILD_CRAMDISK

void rd_load(void);

static int crd_load(struct file *fp, struct file *outfp);

#ifdef CONFIG_BLK_DEV_INITRD

static int initrd_users = 0;

#endif

#endif

/* Various static variables go here... mostly used within the ramdisk code only. */

static int rd_length[NUM_RAMDISKS];

static int rd_blocksizes[NUM_RAMDISKS];

/*

 * Parameters for the boot-loading of the ramdisk.  These are set by

 * init/main.c (from arguments to the kernel command line) or from the

 * architecture-specific setup routine (from the stored bootsector

 * information).

 */

int rd_size = 4096;             /* Size of the ramdisks */

#ifndef MODULE

int rd_doload = 0;               /* 1 = load ramdisk, 0 = don't load */

int rd_prompt = 1;              /* 1 = prompt for ramdisk, 0 = don't prompt */

int rd_image_start = 0;          /* starting block # of image */

#ifdef CONFIG_BLK_DEV_INITRD

unsigned long initrd_start,initrd_end;

int mount_initrd = 1;           /* zero if initrd should not be mounted */

#endif

#endif

/*

 *  Basically, my strategy here is to set up a buffer-head which can't be

 *  deleted, and make that my Ramdisk.  If the request is outside of the

 *  allocated size, we must get rid of it...

 *

 */

static void rd_request(void)

{

        unsigned int minor;

        int offset, len;

repeat:

        INIT_REQUEST;

        minor = MINOR(CURRENT->rq_dev);

        if (minor >= NUM_RAMDISKS) {

                end_request(0);

                goto repeat;

        }

        offset = CURRENT->sector << 9;

        len = CURRENT->current_nr_sectors << 9;

        if ((offset + len) > rd_length[minor]) {

                end_request(0);

                goto repeat;

        }

        /*

         * If we're reading, fill the buffer with 0's.  This is okay since

         * we're using protected buffers which should never get freed...

         *

         * If we're writing, we protect the buffer.

         */

        if (CURRENT->cmd == READ)

                memset(CURRENT->buffer, 0, len);

        else

                set_bit(BH_Protected, &CURRENT->bh->b_state);

        end_request(1);

        goto repeat;

}

static int rd_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)

{

        int err;

        if (!inode || !inode->i_rdev)

                return -EINVAL;

        switch (cmd) {

                case BLKFLSBUF:

                        if (!suser()) return -EACCES;

                        invalidate_buffers(inode->i_rdev);

                        break;

                case BLKGETSIZE:   /* Return device size */

                        if (!arg)  return -EINVAL;

                        err = verify_area(VERIFY_WRITE, (long *) arg,

                                          sizeof(long));

                        if (err)

                                return err;

                        put_user(rd_length[MINOR(inode->i_rdev)] / 512,

                                 (long *) arg);

                        return 0;

                default:

                        break;

        };

        return 0;

}

#ifdef CONFIG_BLK_DEV_INITRD

static int initrd_read(struct inode *inode,struct file *file,char *buf,

    int count)

{

        int left;

        left = initrd_end-initrd_start-file->f_pos;

        if (count > left) count = left;

        if (count <= 0) return 0;

        memcpy_tofs(buf,(char *) initrd_start+file->f_pos,count);

        file->f_pos += count;

        return count;

}

static void initrd_release(struct inode *inode,struct file *file)

{

        unsigned long i;

        if (--initrd_users) return;

        for (i = initrd_start; i < initrd_end; i += PAGE_SIZE)

                free_page(i);

        initrd_start = 0;

}

static struct file_operations initrd_fops = {

        NULL,           /* lseek */

        initrd_read,    /* read */

        NULL,           /* write */

        NULL,           /* readdir */

        NULL,           /* select */

        NULL,           /* ioctl */

        NULL,           /* mmap */

        NULL,           /* open */

        initrd_release, /* release */

        NULL            /* fsync */

};

#endif

static int rd_open(struct inode * inode, struct file * filp)

{

#ifdef CONFIG_BLK_DEV_INITRD

        if (DEVICE_NR(inode->i_rdev) == INITRD_MINOR) {

                if (!initrd_start) return -ENODEV;

                initrd_users++;

                filp->f_op = &initrd_fops;

                return 0;

        }

#endif

        if (DEVICE_NR(inode->i_rdev) >= NUM_RAMDISKS)

                return -ENXIO;

        MOD_INC_USE_COUNT;

        return 0;

}

#ifdef MODULE

static void rd_release(struct inode * inode, struct file * filp)

{

        MOD_DEC_USE_COUNT;

}

#endif

static struct file_operations fd_fops = {

        NULL,           /* lseek - default */

        block_read,     /* read - block dev read */

        block_write,    /* write - block dev write */

        NULL,           /* readdir - not here! */

        NULL,           /* select */

        rd_ioctl,       /* ioctl */

        NULL,           /* mmap */

        rd_open,        /* open */

#ifndef MODULE

        NULL,           /* no special release code... */

#else

        rd_release,     /* module needs to decrement use count */

#endif

        block_fsync             /* fsync */

};

/* This is the registration and initialization section of the ramdisk driver */

int rd_init(void)

{

        int             i;

        if (register_blkdev(MAJOR_NR, "ramdisk", &fd_fops)) {

                printk("RAMDISK: Could not get major %d", MAJOR_NR);

                return -EIO;

        }

        blk_dev[MAJOR_NR].request_fn = &rd_request;

        for (i = 0; i < NUM_RAMDISKS; i++) {

                rd_length[i] = (rd_size * 1024);

                rd_blocksizes[i] = 1024;

        }

        blksize_size[MAJOR_NR] = rd_blocksizes;

        printk("Ramdisk driver initialized : %d ramdisks of %dK size\n",

                                                        NUM_RAMDISKS, rd_size);

        return 0;

}

/* loadable module support */

#ifdef MODULE

int init_module(void)

{

        int error = rd_init();

        if (!error)

                printk(KERN_INFO "RAMDISK: Loaded as module.\n");

        return error;

}

/* Before freeing the module, invalidate all of the protected buffers! */

void cleanup_module(void)

{

        int i;

        for (i = 0 ; i < NUM_RAMDISKS; i++)

                invalidate_buffers(MKDEV(MAJOR_NR, i));

        unregister_blkdev( MAJOR_NR, "ramdisk" );

        blk_dev[MAJOR_NR].request_fn = 0;

}

#endif  /* MODULE */

/* End of non-loading portions of the ramdisk driver */

#ifdef RD_LOADER 

/*

 * This routine tries to a ramdisk image to load, and returns the

 * number of blocks to read for a non-compressed image, 0 if the image

 * is a compressed image, and -1 if an image with the right magic

 * numbers could not be found.

 *

 * We currently check for the following magic numbers:

 *      minix

 *      ext2

 *      gzip

 */

int

identify_ramdisk_image(kdev_t device, struct file *fp, int start_block)

{

        const int size = 512;

        struct minix_super_block *minixsb;

        struct ext2_super_block *ext2sb;

        int nblocks = -1;

        int max_blocks;

        unsigned char *buf;

        buf = kmalloc(size, GFP_KERNEL);

        if (buf == 0)

                return -1;

        minixsb = (struct minix_super_block *) buf;

        ext2sb = (struct ext2_super_block *) buf;

        memset(buf, 0xe5, size);

        /*

         * Read block 0 to test for gzipped kernel

         */

        if (fp->f_op->lseek)

                fp->f_op->lseek(fp->f_inode, fp, start_block * BLOCK_SIZE, 0);

        fp->f_pos = start_block * BLOCK_SIZE;

        fp->f_op->read(fp->f_inode, fp, buf, size);

        /*

         * If it matches the gzip magic numbers, return -1

         */

        if (buf[0] == 037 && ((buf[1] == 0213) || (buf[1] == 0236))) {

                printk(KERN_NOTICE

                       "RAMDISK: Compressed image found at block %d\n",

                       start_block);

                nblocks = 0;

                goto done;

        }

        /*

         * Read block 1 to test for minix and ext2 superblock

         */

        if (fp->f_op->lseek)

                fp->f_op->lseek(fp->f_inode, fp,

                                (start_block+1) * BLOCK_SIZE, 0);

        fp->f_pos = (start_block+1) * BLOCK_SIZE;

        fp->f_op->read(fp->f_inode, fp, buf, size);

        /* Try minix */

        if (minixsb->s_magic == MINIX_SUPER_MAGIC ||

            minixsb->s_magic == MINIX_SUPER_MAGIC2) {

                printk(KERN_NOTICE

                       "RAMDISK: Minix filesystem found at block %d\n",

                       start_block);

                nblocks = minixsb->s_nzones << minixsb->s_log_zone_size;

                goto done;

        }

        /* Try ext2 */

        if (ext2sb->s_magic == EXT2_SUPER_MAGIC) {

                printk(KERN_NOTICE

                       "RAMDISK: Ext2 filesystem found at block %d\n",

                       start_block);

                nblocks = ext2sb->s_blocks_count;

                goto done;

        }

        printk(KERN_NOTICE

               "RAMDISK: Couldn't find valid ramdisk image starting at %d.\n",

               start_block);

done:

        if (fp->f_op->lseek)

                fp->f_op->lseek(fp->f_inode, fp, start_block * BLOCK_SIZE, 0);

        fp->f_pos = start_block * BLOCK_SIZE;

        if ((nblocks > 0) && blk_size[MAJOR(device)]) {

                max_blocks = blk_size[MAJOR(device)][MINOR(device)];

                max_blocks -= start_block;

                if (nblocks > max_blocks) {

                        printk(KERN_NOTICE

                               "RAMDISK: Restricting filesystem size "

                               "from %d to %d blocks.\n",

                               nblocks, max_blocks);

                        nblocks = max_blocks;

                }

        }

        kfree(buf);

        return nblocks;

}

/*

 * This routine loads in the ramdisk image.

 */

static void rd_load_image(kdev_t device,int offset, int unit)

{

        struct inode inode, out_inode;

        struct file infile, outfile;

        unsigned short fs;

        kdev_t ram_device;

        int nblocks, i;

        char *buf;

        unsigned short rotate = 0;

        char rotator[4] = { '|' , '/' , '-' , '\\' };

        ram_device = MKDEV(MAJOR_NR, unit);

        memset(&infile, 0, sizeof(infile));

        memset(&inode, 0, sizeof(inode));

        inode.i_rdev = device;

        infile.f_mode = 1; /* read only */

        infile.f_inode = &inode;

        memset(&outfile, 0, sizeof(outfile));

        memset(&out_inode, 0, sizeof(out_inode));

        out_inode.i_rdev = ram_device;

        outfile.f_mode = 3; /* read/write */

        outfile.f_inode = &out_inode;

        if (blkdev_open(&inode, &infile) != 0) return;

        if (blkdev_open(&out_inode, &outfile) != 0) return;

        fs = get_fs();

        set_fs(KERNEL_DS);

        nblocks = identify_ramdisk_image(device, &infile, offset);

        if (nblocks < 0)

                goto done;

        if (nblocks == 0) {

#ifdef BUILD_CRAMDISK

                if (crd_load(&infile, &outfile) == 0)

                        goto successful_load;

#else

                printk(KERN_NOTICE

                       "RAMDISK: Kernel does not support compressed "

                       "ramdisk images\n");

#endif

                goto done;

        }

        if (nblocks > (rd_length[0] >> BLOCK_SIZE_BITS)) {

                printk("RAMDISK: image too big! (%d/%d blocks)\n",

                       nblocks, rd_length[0] >> BLOCK_SIZE_BITS);

                goto done;

        }

        /*

         * OK, time to copy in the data

         */

        buf = kmalloc(BLOCK_SIZE, GFP_KERNEL);

        if (buf == 0) {

                printk(KERN_ERR "RAMDISK: could not allocate buffer\n");

                goto done;

        }

        printk(KERN_NOTICE "RAMDISK: Loading %d blocks into ram disk... ", nblocks);

        for (i=0; i < nblocks; i++) {

                infile.f_op->read(infile.f_inode, &infile, buf,

                                  BLOCK_SIZE);

                outfile.f_op->write(outfile.f_inode, &outfile, buf,

                                    BLOCK_SIZE);

                if (!(i % 16)) {

                        printk("%c\b", rotator[rotate & 0x3]);

                        rotate++;

                }

        }

        printk("done.\n");

        kfree(buf);

successful_load:

        invalidate_buffers(device);

        ROOT_DEV = MKDEV(MAJOR_NR,unit);

done:

        if (infile.f_op->release)

                infile.f_op->release(&inode, &infile);

        set_fs(fs);

}

static void rd_load_disk(int n)

{

#ifdef CONFIG_BLK_DEV_INITRD

        extern kdev_t real_root_dev;

#endif  

        if (rd_doload == 0)

                return;

        if (MAJOR(ROOT_DEV) != FLOPPY_MAJOR

#ifdef CONFIG_BLK_DEV_INITRD    

                && MAJOR(real_root_dev) != FLOPPY_MAJOR

#endif          

        )

                        return;

        if (rd_prompt) {

#ifdef CONFIG_BLK_DEV_FD

                floppy_eject();

#endif

                printk(KERN_NOTICE

                       "VFS: Insert root floppy disk to be loaded into ramdisk and press ENTER\n");

                wait_for_keypress();

        }

        rd_load_image(ROOT_DEV,rd_image_start,n);

}

void rd_load(void)

{

        rd_load_disk(0);

}

void rd_load_secondary(void)

{

        rd_load_disk(1);

}

#ifdef CONFIG_BLK_DEV_INITRD

void initrd_load(void)

{

        rd_load_image(MKDEV(MAJOR_NR, INITRD_MINOR),0,0);

}

#endif

#endif /* RD_LOADER */

#ifdef BUILD_CRAMDISK

/*

 * gzip declarations

 */

#define OF(args)  args

#define memzero(s, n)     memset ((s), 0, (n))

typedef unsigned char  uch;

typedef unsigned short ush;

typedef unsigned long  ulg;

#define INBUFSIZ 4096

#define WSIZE 0x8000    /* window size--must be a power of two, and */

                        /*  at least 32K for zip's deflate method */

static uch *inbuf;

static uch *window;

static unsigned insize = 0;  /* valid bytes in inbuf */

static unsigned inptr = 0;   /* index of next byte to be processed in inbuf */

static unsigned outcnt = 0;  /* bytes in output buffer */

static int exit_code = 0;

static long bytes_out = 0;

static struct file *crd_infp, *crd_outfp;

#define get_byte()  (inptr < insize ? inbuf[inptr++] : fill_inbuf())

/* Diagnostic functions (stubbed out) */

#define Assert(cond,msg)

#define Trace(x)

#define Tracev(x)

#define Tracevv(x)

#define Tracec(c,x)

#define Tracecv(c,x)

#define STATIC static

static int  fill_inbuf(void);

static void flush_window(void);

static void *malloc(int size);

static void free(void *where);

static void error(char *m);

static void gzip_mark(void **);

static void gzip_release(void **);

#include "../../../../lib/inflate.c"

static void *malloc(int size)

{

        return kmalloc(size, GFP_KERNEL);

}

static void free(void *where)

{

        kfree(where);

}

static void gzip_mark(void **ptr)

{

}

static void gzip_release(void **ptr)

{

}

/* ===========================================================================

 * Fill the input buffer. This is called only when the buffer is empty

 * and at least one byte is really needed.

 */

static int fill_inbuf()

{

        if (exit_code) return -1;

        insize = crd_infp->f_op->read(crd_infp->f_inode, crd_infp,

                                      inbuf, INBUFSIZ);

        if (insize == 0) return -1;

        inptr = 1;

        return inbuf[0];

}

/* ===========================================================================

 * Write the output window window[0..outcnt-1] and update crc and bytes_out.

 * (Used for the decompressed data only.)

 */

static void flush_window()

{

    ulg c = crc;         /* temporary variable */

    unsigned n;

    uch *in, ch;

    crd_outfp->f_op->write(crd_outfp->f_inode, crd_outfp, window,

                           outcnt);

    in = window;

    for (n = 0; n < outcnt; n++) {

            ch = *in++;

            c = crc_32_tab[((int)c ^ ch) & 0xff] ^ (c >> 8);

    }

    crc = c;

    bytes_out += (ulg)outcnt;

    outcnt = 0;

}

static void error(char *x)

{

        printk(KERN_ERR "%s", x);

        exit_code = 1;

}

static int

crd_load(struct file * fp, struct file *outfp)

{

        int result;

        insize = 0;  /* valid bytes in inbuf */

        inptr = 0;   /* index of next byte to be processed in inbuf */

        outcnt = 0;  /* bytes in output buffer */

        exit_code = 0;

        bytes_out = 0;

        crc = 0xFFFFFFFF;

        crd_infp = fp;

        crd_outfp = outfp;

        inbuf = kmalloc(INBUFSIZ, GFP_KERNEL);

        if (inbuf == 0) {

                printk(KERN_ERR "RAMDISK: Couldn't allocate gzip buffer\n");

                return -1;

        }

        window = kmalloc(WSIZE, GFP_KERNEL);

        if (window == 0) {