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executable file 328 lines (286 sloc) 8.255 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 <linux/slab.h>
#include "do_mounts.h"
#include "../fs/squashfs/squashfs_fs.h"
#include <linux/decompress/generic.h>
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, decompress_fn deco);
/*
* 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
* squashfs
* gzip
*/
static int __init
identify_ramdisk_image(int fd, int start_block, decompress_fn *decompressor)
{
const int size = 512;
struct minix_super_block *minixsb;
struct ext2_super_block *ext2sb;
struct romfs_super_block *romfsb;
struct cramfs_super *cramfsb;
struct squashfs_super_block *squashfsb;
int nblocks = -1;
unsigned char *buf;
const char *compress_name;
buf = kmalloc(size, GFP_KERNEL);
if (!buf)
return -ENOMEM;
minixsb = (struct minix_super_block *) buf;
ext2sb = (struct ext2_super_block *) buf;
romfsb = (struct romfs_super_block *) buf;
cramfsb = (struct cramfs_super *) buf;
squashfsb = (struct squashfs_super_block *) buf;
memset(buf, 0xe5, size);
/*
* Read block 0 to test for compressed kernel
*/
sys_lseek(fd, start_block * BLOCK_SIZE, 0);
sys_read(fd, buf, size);
*decompressor = decompress_method(buf, size, &compress_name);
if (compress_name) {
printk(KERN_NOTICE "RAMDISK: %s image found at block %d\n",
compress_name, start_block);
if (!*decompressor)
printk(KERN_EMERG
"RAMDISK: %s decompressor not configured!\n",
compress_name);
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;
}
/* squashfs is at block zero too */
if (le32_to_cpu(squashfsb->s_magic) == SQUASHFS_MAGIC) {
printk(KERN_NOTICE
"RAMDISK: squashfs filesystem found at block %d\n",
start_block);
nblocks = (le64_to_cpu(squashfsb->bytes_used) + 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;
decompress_fn decompressor = NULL;
#if !defined(CONFIG_S390) && !defined(CONFIG_PPC_ISERIES)
char rotator[4] = { '|' , '/' , '-' , '\\' };
#endif
out_fd = sys_open((const char __user __force *) "/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, &decompressor);
if (nblocks < 0)
goto done;
if (nblocks == 0) {
if (crd_load(in_fd, out_fd, decompressor) == 0)
goto successful_load;
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) {
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((const char __user __force *) "/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");
}
static int exit_code;
static int decompress_error;
static int crd_infd, crd_outfd;
static int __init compr_fill(void *buf, unsigned int len)
{
int r = sys_read(crd_infd, buf, len);
if (r < 0)
printk(KERN_ERR "RAMDISK: error while reading compressed data");
else if (r == 0)
printk(KERN_ERR "RAMDISK: EOF while reading compressed data");
return r;
}
static int __init compr_flush(void *window, unsigned int outcnt)
{
int written = sys_write(crd_outfd, window, outcnt);
if (written != outcnt) {
if (decompress_error == 0)
printk(KERN_ERR
"RAMDISK: incomplete write (%d != %d)\n",
written, outcnt);
decompress_error = 1;
return -1;
}
return outcnt;
}
static void __init error(char *x)
{
printk(KERN_ERR "%s\n", x);
exit_code = 1;
decompress_error = 1;
}
static int __init crd_load(int in_fd, int out_fd, decompress_fn deco)
{
int result;
crd_infd = in_fd;
crd_outfd = out_fd;
result = deco(NULL, 0, compr_fill, compr_flush, NULL, NULL, error);
if (decompress_error)
result = 1;
return result;
}
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