/*
* 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)
{
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, 0);
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,0);
done:
if (infile.f_op->release)
infile.f_op->release(&inode, &infile);
set_fs(fs);
}
void rd_load()
{
if (rd_doload == 0)
return;
if (MAJOR(ROOT_DEV) != FLOPPY_MAJOR) 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);
}
#ifdef CONFIG_BLK_DEV_INITRD
void initrd_load(void)
{
rd_load_image(MKDEV(MAJOR_NR, INITRD_MINOR),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 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;
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) {
printk(KERN_ERR "RAMDISK: Couldn't allocate gzip window\n");
kfree(inbuf);
return -1;
}
makecrc();
result = gunzip();
kfree(inbuf);
kfree(window);
return result;
}
#endif /* BUILD_CRAMDISK */
