430 lines
10 KiB
C
430 lines
10 KiB
C
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#include <linux/kernel.h>
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#include <linux/fs.h>
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#include <linux/minix_fs.h>
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#include <linux/ext2_fs.h>
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#include <linux/romfs_fs.h>
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#include <linux/cramfs_fs.h>
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#include <linux/initrd.h>
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#include <linux/string.h>
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#include "do_mounts.h"
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#define BUILD_CRAMDISK
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int __initdata rd_prompt = 1;/* 1 = prompt for RAM disk, 0 = don't prompt */
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static int __init prompt_ramdisk(char *str)
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{
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rd_prompt = simple_strtol(str,NULL,0) & 1;
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return 1;
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}
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__setup("prompt_ramdisk=", prompt_ramdisk);
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int __initdata rd_image_start; /* starting block # of image */
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static int __init ramdisk_start_setup(char *str)
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{
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rd_image_start = simple_strtol(str,NULL,0);
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return 1;
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}
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__setup("ramdisk_start=", ramdisk_start_setup);
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static int __init crd_load(int in_fd, int out_fd);
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/*
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* This routine tries to find a RAM disk image to load, and returns the
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* number of blocks to read for a non-compressed image, 0 if the image
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* is a compressed image, and -1 if an image with the right magic
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* numbers could not be found.
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*
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* We currently check for the following magic numbers:
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* minix
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* ext2
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* romfs
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* cramfs
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* gzip
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*/
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static int __init
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identify_ramdisk_image(int fd, int start_block)
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{
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const int size = 512;
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struct minix_super_block *minixsb;
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struct ext2_super_block *ext2sb;
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struct romfs_super_block *romfsb;
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struct cramfs_super *cramfsb;
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int nblocks = -1;
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unsigned char *buf;
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buf = kmalloc(size, GFP_KERNEL);
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if (buf == 0)
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return -1;
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minixsb = (struct minix_super_block *) buf;
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ext2sb = (struct ext2_super_block *) buf;
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romfsb = (struct romfs_super_block *) buf;
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cramfsb = (struct cramfs_super *) buf;
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memset(buf, 0xe5, size);
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/*
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* Read block 0 to test for gzipped kernel
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*/
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sys_lseek(fd, start_block * BLOCK_SIZE, 0);
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sys_read(fd, buf, size);
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/*
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* If it matches the gzip magic numbers, return -1
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*/
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if (buf[0] == 037 && ((buf[1] == 0213) || (buf[1] == 0236))) {
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printk(KERN_NOTICE
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"RAMDISK: Compressed image found at block %d\n",
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start_block);
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nblocks = 0;
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goto done;
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}
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/* romfs is at block zero too */
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if (romfsb->word0 == ROMSB_WORD0 &&
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romfsb->word1 == ROMSB_WORD1) {
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printk(KERN_NOTICE
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"RAMDISK: romfs filesystem found at block %d\n",
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start_block);
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nblocks = (ntohl(romfsb->size)+BLOCK_SIZE-1)>>BLOCK_SIZE_BITS;
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goto done;
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}
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if (cramfsb->magic == CRAMFS_MAGIC) {
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printk(KERN_NOTICE
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"RAMDISK: cramfs filesystem found at block %d\n",
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start_block);
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nblocks = (cramfsb->size + BLOCK_SIZE - 1) >> BLOCK_SIZE_BITS;
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goto done;
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}
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/*
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* Read block 1 to test for minix and ext2 superblock
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*/
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sys_lseek(fd, (start_block+1) * BLOCK_SIZE, 0);
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sys_read(fd, buf, size);
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/* Try minix */
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if (minixsb->s_magic == MINIX_SUPER_MAGIC ||
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minixsb->s_magic == MINIX_SUPER_MAGIC2) {
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printk(KERN_NOTICE
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"RAMDISK: Minix filesystem found at block %d\n",
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start_block);
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nblocks = minixsb->s_nzones << minixsb->s_log_zone_size;
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goto done;
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}
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/* Try ext2 */
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if (ext2sb->s_magic == cpu_to_le16(EXT2_SUPER_MAGIC)) {
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printk(KERN_NOTICE
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"RAMDISK: ext2 filesystem found at block %d\n",
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start_block);
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nblocks = le32_to_cpu(ext2sb->s_blocks_count) <<
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le32_to_cpu(ext2sb->s_log_block_size);
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goto done;
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}
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printk(KERN_NOTICE
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"RAMDISK: Couldn't find valid RAM disk image starting at %d.\n",
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start_block);
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done:
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sys_lseek(fd, start_block * BLOCK_SIZE, 0);
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kfree(buf);
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return nblocks;
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}
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int __init rd_load_image(char *from)
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{
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int res = 0;
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int in_fd, out_fd;
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unsigned long rd_blocks, devblocks;
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int nblocks, i, disk;
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char *buf = NULL;
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unsigned short rotate = 0;
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#if !defined(CONFIG_S390) && !defined(CONFIG_PPC_ISERIES)
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char rotator[4] = { '|' , '/' , '-' , '\\' };
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#endif
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out_fd = sys_open("/dev/ram", O_RDWR, 0);
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if (out_fd < 0)
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goto out;
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in_fd = sys_open(from, O_RDONLY, 0);
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if (in_fd < 0)
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goto noclose_input;
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nblocks = identify_ramdisk_image(in_fd, rd_image_start);
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if (nblocks < 0)
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goto done;
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if (nblocks == 0) {
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#ifdef BUILD_CRAMDISK
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if (crd_load(in_fd, out_fd) == 0)
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goto successful_load;
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#else
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printk(KERN_NOTICE
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"RAMDISK: Kernel does not support compressed "
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"RAM disk images\n");
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#endif
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goto done;
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}
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/*
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* NOTE NOTE: nblocks is not actually blocks but
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* the number of kibibytes of data to load into a ramdisk.
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* So any ramdisk block size that is a multiple of 1KiB should
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* work when the appropriate ramdisk_blocksize is specified
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* on the command line.
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*
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* The default ramdisk_blocksize is 1KiB and it is generally
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* silly to use anything else, so make sure to use 1KiB
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* blocksize while generating ext2fs ramdisk-images.
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*/
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if (sys_ioctl(out_fd, BLKGETSIZE, (unsigned long)&rd_blocks) < 0)
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rd_blocks = 0;
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else
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rd_blocks >>= 1;
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if (nblocks > rd_blocks) {
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printk("RAMDISK: image too big! (%dKiB/%ldKiB)\n",
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nblocks, rd_blocks);
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goto done;
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}
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/*
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* OK, time to copy in the data
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*/
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if (sys_ioctl(in_fd, BLKGETSIZE, (unsigned long)&devblocks) < 0)
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devblocks = 0;
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else
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devblocks >>= 1;
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if (strcmp(from, "/initrd.image") == 0)
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devblocks = nblocks;
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if (devblocks == 0) {
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printk(KERN_ERR "RAMDISK: could not determine device size\n");
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goto done;
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}
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buf = kmalloc(BLOCK_SIZE, GFP_KERNEL);
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if (buf == 0) {
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printk(KERN_ERR "RAMDISK: could not allocate buffer\n");
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goto done;
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}
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printk(KERN_NOTICE "RAMDISK: Loading %dKiB [%ld disk%s] into ram disk... ",
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nblocks, ((nblocks-1)/devblocks)+1, nblocks>devblocks ? "s" : "");
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for (i = 0, disk = 1; i < nblocks; i++) {
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if (i && (i % devblocks == 0)) {
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printk("done disk #%d.\n", disk++);
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rotate = 0;
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if (sys_close(in_fd)) {
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printk("Error closing the disk.\n");
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goto noclose_input;
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}
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change_floppy("disk #%d", disk);
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in_fd = sys_open(from, O_RDONLY, 0);
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if (in_fd < 0) {
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printk("Error opening disk.\n");
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goto noclose_input;
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}
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printk("Loading disk #%d... ", disk);
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}
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sys_read(in_fd, buf, BLOCK_SIZE);
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sys_write(out_fd, buf, BLOCK_SIZE);
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#if !defined(CONFIG_S390) && !defined(CONFIG_PPC_ISERIES)
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if (!(i % 16)) {
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printk("%c\b", rotator[rotate & 0x3]);
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rotate++;
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}
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#endif
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}
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printk("done.\n");
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successful_load:
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res = 1;
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done:
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sys_close(in_fd);
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noclose_input:
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sys_close(out_fd);
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out:
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kfree(buf);
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sys_unlink("/dev/ram");
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return res;
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}
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int __init rd_load_disk(int n)
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{
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if (rd_prompt)
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change_floppy("root floppy disk to be loaded into RAM disk");
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create_dev("/dev/root", ROOT_DEV);
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create_dev("/dev/ram", MKDEV(RAMDISK_MAJOR, n));
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return rd_load_image("/dev/root");
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}
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#ifdef BUILD_CRAMDISK
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/*
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* gzip declarations
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*/
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#define OF(args) args
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#ifndef memzero
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#define memzero(s, n) memset ((s), 0, (n))
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#endif
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typedef unsigned char uch;
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typedef unsigned short ush;
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typedef unsigned long ulg;
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#define INBUFSIZ 4096
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#define WSIZE 0x8000 /* window size--must be a power of two, and */
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/* at least 32K for zip's deflate method */
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static uch *inbuf;
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static uch *window;
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static unsigned insize; /* valid bytes in inbuf */
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static unsigned inptr; /* index of next byte to be processed in inbuf */
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static unsigned outcnt; /* bytes in output buffer */
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static int exit_code;
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static int unzip_error;
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static long bytes_out;
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static int crd_infd, crd_outfd;
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#define get_byte() (inptr < insize ? inbuf[inptr++] : fill_inbuf())
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/* Diagnostic functions (stubbed out) */
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#define Assert(cond,msg)
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#define Trace(x)
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#define Tracev(x)
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#define Tracevv(x)
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#define Tracec(c,x)
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#define Tracecv(c,x)
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#define STATIC static
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#define INIT __init
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static int __init fill_inbuf(void);
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static void __init flush_window(void);
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static void __init *malloc(size_t size);
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static void __init free(void *where);
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static void __init error(char *m);
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static void __init gzip_mark(void **);
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static void __init gzip_release(void **);
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#include "../lib/inflate.c"
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static void __init *malloc(size_t size)
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{
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return kmalloc(size, GFP_KERNEL);
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}
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static void __init free(void *where)
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{
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kfree(where);
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}
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static void __init gzip_mark(void **ptr)
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{
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}
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static void __init gzip_release(void **ptr)
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{
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}
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/* ===========================================================================
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* Fill the input buffer. This is called only when the buffer is empty
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* and at least one byte is really needed.
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* Returning -1 does not guarantee that gunzip() will ever return.
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*/
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static int __init fill_inbuf(void)
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{
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if (exit_code) return -1;
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insize = sys_read(crd_infd, inbuf, INBUFSIZ);
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if (insize == 0) {
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error("RAMDISK: ran out of compressed data");
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return -1;
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}
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inptr = 1;
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return inbuf[0];
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}
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/* ===========================================================================
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* Write the output window window[0..outcnt-1] and update crc and bytes_out.
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* (Used for the decompressed data only.)
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*/
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static void __init flush_window(void)
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{
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ulg c = crc; /* temporary variable */
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unsigned n, written;
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uch *in, ch;
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written = sys_write(crd_outfd, window, outcnt);
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if (written != outcnt && unzip_error == 0) {
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printk(KERN_ERR "RAMDISK: incomplete write (%d != %d) %ld\n",
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written, outcnt, bytes_out);
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unzip_error = 1;
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}
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in = window;
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for (n = 0; n < outcnt; n++) {
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ch = *in++;
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c = crc_32_tab[((int)c ^ ch) & 0xff] ^ (c >> 8);
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}
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crc = c;
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bytes_out += (ulg)outcnt;
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outcnt = 0;
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}
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static void __init error(char *x)
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{
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printk(KERN_ERR "%s\n", x);
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exit_code = 1;
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unzip_error = 1;
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}
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static int __init crd_load(int in_fd, int out_fd)
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{
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int result;
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insize = 0; /* valid bytes in inbuf */
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inptr = 0; /* index of next byte to be processed in inbuf */
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outcnt = 0; /* bytes in output buffer */
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exit_code = 0;
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bytes_out = 0;
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crc = (ulg)0xffffffffL; /* shift register contents */
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crd_infd = in_fd;
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crd_outfd = out_fd;
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inbuf = kmalloc(INBUFSIZ, GFP_KERNEL);
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if (inbuf == 0) {
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printk(KERN_ERR "RAMDISK: Couldn't allocate gzip buffer\n");
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return -1;
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}
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window = kmalloc(WSIZE, GFP_KERNEL);
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if (window == 0) {
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printk(KERN_ERR "RAMDISK: Couldn't allocate gzip window\n");
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kfree(inbuf);
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return -1;
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}
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makecrc();
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result = gunzip();
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if (unzip_error)
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result = 1;
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kfree(inbuf);
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kfree(window);
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return result;
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}
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#endif /* BUILD_CRAMDISK */
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