rd.c

arm平台上的uclinux系统全部源代码

	
	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) {
		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 */