// SPDX-License-Identifier: GPL-2.0#include <linux/kernel.h>#include <linux/fs.h>#include <linux/minix_fs.h>#include <linux/ext2_fs.h>#include <linux/romfs_fs.h>#include <uapi/linux/cramfs_fs.h>#include <linux/initrd.h>#include <linux/string.h>#include <linux/string_choices.h>#include <linux/slab.h> #include "do_mounts.h"#include "../fs/squashfs/squashfs_fs.h" #include <linux/decompress/generic.h> static struct file *in_file, *out_file;static loff_t in_pos, out_pos; int __initdata rd_image_start;		/* starting block # of image */ static int __init ramdisk_start_setup(char *str){	pr_warn("ramdisk_start= option is deprecated and will be removed soon\n");	return kstrtoint(str, 0, &rd_image_start) == 0;}__setup("ramdisk_start=", ramdisk_start_setup); static int __init crd_load(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 *	bzip2 *	lzma *	xz *	lzo *	lz4 */static int __initidentify_ramdisk_image(struct file *file, loff_t pos,		decompress_fn *decompressor){	const int size = 512;	struct minix_super_block *minixsb;	struct romfs_super_block *romfsb;	struct cramfs_super *cramfsb;	struct squashfs_super_block *squashfsb;	int nblocks = -1;	unsigned char *buf;	const char *compress_name;	unsigned long n;	int start_block = rd_image_start; 	buf = kmalloc(size, GFP_KERNEL);	if (!buf)		return -ENOMEM; 	minixsb = (struct minix_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	 */	pos = start_block * BLOCK_SIZE;	kernel_read(file, buf, size, &pos); 	*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 512 bytes further to check if cramfs is padded	 */	pos = start_block * BLOCK_SIZE + 0x200;	kernel_read(file, buf, size, &pos); 	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	 */	pos = (start_block + 1) * BLOCK_SIZE;	kernel_read(file, buf, size, &pos); 	/* 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 */	n = ext2_image_size(buf);	if (n) {		printk(KERN_NOTICE		       "RAMDISK: ext2 filesystem found at block %d\n",		       start_block);		nblocks = n;		goto done;	} 	printk(KERN_NOTICE	       "RAMDISK: Couldn't find valid RAM disk image starting at %d.\n",	       start_block); done:	kfree(buf);	return nblocks;} static unsigned long nr_blocks(struct file *file){	struct inode *inode = file->f_mapping->host; 	if (!S_ISBLK(inode->i_mode))		return 0;	return i_size_read(inode) >> 10;} int __init rd_load_image(void){	int res = 0;	unsigned long rd_blocks, devblocks, nr_disks;	int nblocks, i;	char *buf = NULL;	unsigned short rotate = 0;	decompress_fn decompressor = NULL;	char rotator[4] = { '|' , '/' , '-' , '\\' }; 	out_file = filp_open("/dev/ram", O_RDWR, 0);	if (IS_ERR(out_file))		goto out; 	in_file = filp_open("/initrd.image", O_RDONLY, 0);	if (IS_ERR(in_file))		goto noclose_input; 	in_pos = rd_image_start * BLOCK_SIZE;	nblocks = identify_ramdisk_image(in_file, in_pos, &decompressor);	if (nblocks < 0)		goto done; 	if (nblocks == 0) {		if (crd_load(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.	 */	rd_blocks = nr_blocks(out_file);	if (nblocks > rd_blocks) {		printk("RAMDISK: image too big! (%dKiB/%ldKiB)\n",		       nblocks, rd_blocks);		goto done;	} 	/*	 * OK, time to copy in the data	 */	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;	} 	nr_disks = (nblocks - 1) / devblocks + 1;	pr_notice("RAMDISK: Loading %dKiB [%ld disk%s] into ram disk... ",		  nblocks, nr_disks, str_plural(nr_disks));	for (i = 0; i < nblocks; i++) {		if (i && (i % devblocks == 0)) {			pr_cont("done disk #1.\n");			rotate = 0;			fput(in_file);			break;		}		kernel_read(in_file, buf, BLOCK_SIZE, &in_pos);		kernel_write(out_file, buf, BLOCK_SIZE, &out_pos);		if (!IS_ENABLED(CONFIG_S390) && !(i % 16)) {			pr_cont("%c\b", rotator[rotate & 0x3]);			rotate++;		}	}	pr_cont("done.\n"); successful_load:	res = 1;done:	fput(in_file);noclose_input:	fput(out_file);out:	kfree(buf);	init_unlink("/dev/ram");	return res;} static int exit_code;static int decompress_error; static long __init compr_fill(void *buf, unsigned long len){	long r = kernel_read(in_file, buf, len, &in_pos);	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 long __init compr_flush(void *window, unsigned long outcnt){	long written = kernel_write(out_file, window, outcnt, &out_pos);	if (written != outcnt) {		if (decompress_error == 0)			printk(KERN_ERR			       "RAMDISK: incomplete write (%ld != %ld)\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(decompress_fn deco){	int result; 	if (!deco) {		pr_emerg("Invalid ramdisk decompression routine.  "			 "Select appropriate config option.\n");		panic("Could not decompress initial ramdisk image.");	} 	result = deco(NULL, 0, compr_fill, compr_flush, NULL, NULL, error);	if (decompress_error)		result = 1;	return result;}