Skip to content

HTTPS clone URL

Subversion checkout URL

You can clone with
or
.
Download ZIP
Fetching contributors…

Cannot retrieve contributors at this time

430 lines (366 sloc) 10.218 kB
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/minix_fs.h>
#include <linux/ext2_fs.h>
#include <linux/romfs_fs.h>
#include <linux/cramfs_fs.h>
#include <linux/initrd.h>
#include <linux/string.h>
#include "do_mounts.h"
#define BUILD_CRAMDISK
int __initdata rd_prompt = 1;/* 1 = prompt for RAM disk, 0 = don't prompt */
static int __init prompt_ramdisk(char *str)
{
rd_prompt = simple_strtol(str,NULL,0) & 1;
return 1;
}
__setup("prompt_ramdisk=", prompt_ramdisk);
int __initdata rd_image_start; /* starting block # of image */
static int __init ramdisk_start_setup(char *str)
{
rd_image_start = simple_strtol(str,NULL,0);
return 1;
}
__setup("ramdisk_start=", ramdisk_start_setup);
static int __init crd_load(int in_fd, int out_fd);
/*
* This routine tries to find a RAM disk 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
* romfs
* cramfs
* gzip
*/
static int __init
identify_ramdisk_image(int fd, int start_block)
{
const int size = 512;
struct minix_super_block *minixsb;
struct ext2_super_block *ext2sb;
struct romfs_super_block *romfsb;
struct cramfs_super *cramfsb;
int nblocks = -1;
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;
romfsb = (struct romfs_super_block *) buf;
cramfsb = (struct cramfs_super *) buf;
memset(buf, 0xe5, size);
/*
* Read block 0 to test for gzipped kernel
*/
sys_lseek(fd, start_block * BLOCK_SIZE, 0);
sys_read(fd, 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;
}
/* romfs is at block zero too */
if (romfsb->word0 == ROMSB_WORD0 &&
romfsb->word1 == ROMSB_WORD1) {
printk(KERN_NOTICE
"RAMDISK: romfs filesystem found at block %d\n",
start_block);
nblocks = (ntohl(romfsb->size)+BLOCK_SIZE-1)>>BLOCK_SIZE_BITS;
goto done;
}
if (cramfsb->magic == CRAMFS_MAGIC) {
printk(KERN_NOTICE
"RAMDISK: cramfs filesystem found at block %d\n",
start_block);
nblocks = (cramfsb->size + BLOCK_SIZE - 1) >> BLOCK_SIZE_BITS;
goto done;
}
/*
* Read block 1 to test for minix and ext2 superblock
*/
sys_lseek(fd, (start_block+1) * BLOCK_SIZE, 0);
sys_read(fd, 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 == cpu_to_le16(EXT2_SUPER_MAGIC)) {
printk(KERN_NOTICE
"RAMDISK: ext2 filesystem found at block %d\n",
start_block);
nblocks = le32_to_cpu(ext2sb->s_blocks_count) <<
le32_to_cpu(ext2sb->s_log_block_size);
goto done;
}
printk(KERN_NOTICE
"RAMDISK: Couldn't find valid RAM disk image starting at %d.\n",
start_block);
done:
sys_lseek(fd, start_block * BLOCK_SIZE, 0);
kfree(buf);
return nblocks;
}
int __init rd_load_image(char *from)
{
int res = 0;
int in_fd, out_fd;
unsigned long rd_blocks, devblocks;
int nblocks, i, disk;
char *buf = NULL;
unsigned short rotate = 0;
#if !defined(CONFIG_S390) && !defined(CONFIG_PPC_ISERIES)
char rotator[4] = { '|' , '/' , '-' , '\\' };
#endif
out_fd = sys_open("/dev/ram", O_RDWR, 0);
if (out_fd < 0)
goto out;
in_fd = sys_open(from, O_RDONLY, 0);
if (in_fd < 0)
goto noclose_input;
nblocks = identify_ramdisk_image(in_fd, rd_image_start);
if (nblocks < 0)
goto done;
if (nblocks == 0) {
#ifdef BUILD_CRAMDISK
if (crd_load(in_fd, out_fd) == 0)
goto successful_load;
#else
printk(KERN_NOTICE
"RAMDISK: Kernel does not support compressed "
"RAM disk images\n");
#endif
goto done;
}
/*
* NOTE NOTE: nblocks is not actually blocks but
* the number of kibibytes of data to load into a ramdisk.
* So any ramdisk block size that is a multiple of 1KiB should
* work when the appropriate ramdisk_blocksize is specified
* on the command line.
*
* The default ramdisk_blocksize is 1KiB and it is generally
* silly to use anything else, so make sure to use 1KiB
* blocksize while generating ext2fs ramdisk-images.
*/
if (sys_ioctl(out_fd, BLKGETSIZE, (unsigned long)&rd_blocks) < 0)
rd_blocks = 0;
else
rd_blocks >>= 1;
if (nblocks > rd_blocks) {
printk("RAMDISK: image too big! (%dKiB/%ldKiB)\n",
nblocks, rd_blocks);
goto done;
}
/*
* OK, time to copy in the data
*/
if (sys_ioctl(in_fd, BLKGETSIZE, (unsigned long)&devblocks) < 0)
devblocks = 0;
else
devblocks >>= 1;
if (strcmp(from, "/initrd.image") == 0)
devblocks = nblocks;
if (devblocks == 0) {
printk(KERN_ERR "RAMDISK: could not determine device size\n");
goto done;
}
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 %dKiB [%ld disk%s] into ram disk... ",
nblocks, ((nblocks-1)/devblocks)+1, nblocks>devblocks ? "s" : "");
for (i = 0, disk = 1; i < nblocks; i++) {
if (i && (i % devblocks == 0)) {
printk("done disk #%d.\n", disk++);
rotate = 0;
if (sys_close(in_fd)) {
printk("Error closing the disk.\n");
goto noclose_input;
}
change_floppy("disk #%d", disk);
in_fd = sys_open(from, O_RDONLY, 0);
if (in_fd < 0) {
printk("Error opening disk.\n");
goto noclose_input;
}
printk("Loading disk #%d... ", disk);
}
sys_read(in_fd, buf, BLOCK_SIZE);
sys_write(out_fd, buf, BLOCK_SIZE);
#if !defined(CONFIG_S390) && !defined(CONFIG_PPC_ISERIES)
if (!(i % 16)) {
printk("%c\b", rotator[rotate & 0x3]);
rotate++;
}
#endif
}
printk("done.\n");
successful_load:
res = 1;
done:
sys_close(in_fd);
noclose_input:
sys_close(out_fd);
out:
kfree(buf);
sys_unlink("/dev/ram");
return res;
}
int __init rd_load_disk(int n)
{
if (rd_prompt)
change_floppy("root floppy disk to be loaded into RAM disk");
create_dev("/dev/root", ROOT_DEV);
create_dev("/dev/ram", MKDEV(RAMDISK_MAJOR, n));
return rd_load_image("/dev/root");
}
#ifdef BUILD_CRAMDISK
/*
* gzip declarations
*/
#define OF(args) args
#ifndef memzero
#define memzero(s, n) memset ((s), 0, (n))
#endif
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; /* valid bytes in inbuf */
static unsigned inptr; /* index of next byte to be processed in inbuf */
static unsigned outcnt; /* bytes in output buffer */
static int exit_code;
static int unzip_error;
static long bytes_out;
static int crd_infd, crd_outfd;
#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
#define INIT __init
static int __init fill_inbuf(void);
static void __init flush_window(void);
static void __init *malloc(size_t size);
static void __init free(void *where);
static void __init error(char *m);
static void __init gzip_mark(void **);
static void __init gzip_release(void **);
#include "../lib/inflate.c"
static void __init *malloc(size_t size)
{
return kmalloc(size, GFP_KERNEL);
}
static void __init free(void *where)
{
kfree(where);
}
static void __init gzip_mark(void **ptr)
{
}
static void __init 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.
* Returning -1 does not guarantee that gunzip() will ever return.
*/
static int __init fill_inbuf(void)
{
if (exit_code) return -1;
insize = sys_read(crd_infd, inbuf, INBUFSIZ);
if (insize == 0) {
error("RAMDISK: ran out of compressed data");
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 __init flush_window(void)
{
ulg c = crc; /* temporary variable */
unsigned n, written;
uch *in, ch;
written = sys_write(crd_outfd, window, outcnt);
if (written != outcnt && unzip_error == 0) {
printk(KERN_ERR "RAMDISK: incomplete write (%d != %d) %ld\n",
written, outcnt, bytes_out);
unzip_error = 1;
}
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 __init error(char *x)
{
printk(KERN_ERR "%s\n", x);
exit_code = 1;
unzip_error = 1;
}
static int __init crd_load(int in_fd, int out_fd)
{
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 = (ulg)0xffffffffL; /* shift register contents */
crd_infd = in_fd;
crd_outfd = out_fd;
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();
if (unzip_error)
result = 1;
kfree(inbuf);
kfree(window);
return result;
}
#endif /* BUILD_CRAMDISK */
Jump to Line
Something went wrong with that request. Please try again.