// 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/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

   *	bzip2
   *	lzma
   *	xz
   *	lzo
   *	lz4

   */

  static int __init

  identify_ramdisk_image(int fd, int start_block, 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;

  
  	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

  	 */

  	ksys_lseek(fd, start_block * BLOCK_SIZE, 0);

  	ksys_read(fd, buf, size);

  	*decompressor = decompress_method(buf, size, &compress_name);

  	if (compress_name) {

  		printk(KERN_NOTICE "RAMDISK: %s image found at block %d
  ",
  		       compress_name, start_block);

  		if (!*decompressor)

  			printk(KERN_EMERG
  			       "RAMDISK: %s decompressor not configured!
  ",

  			       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
  ",
  		       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
  ",
  		       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
  ",
  		       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
  	 */

  	ksys_lseek(fd, start_block * BLOCK_SIZE + 0x200, 0);

  	ksys_read(fd, buf, size);

  
  	if (cramfsb->magic == CRAMFS_MAGIC) {
  		printk(KERN_NOTICE
  		       "RAMDISK: cramfs filesystem found at block %d
  ",
  		       start_block);
  		nblocks = (cramfsb->size + BLOCK_SIZE - 1) >> BLOCK_SIZE_BITS;
  		goto done;
  	}
  
  	/*

  	 * Read block 1 to test for minix and ext2 superblock
  	 */

  	ksys_lseek(fd, (start_block+1) * BLOCK_SIZE, 0);

  	ksys_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
  ",
  		       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
  ",
  		       start_block);

  		nblocks = n;

  		goto done;
  	}
  
  	printk(KERN_NOTICE
  	       "RAMDISK: Couldn't find valid RAM disk image starting at %d.
  ",
  	       start_block);

  done:

  	ksys_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)

  	char rotator[4] = { '|' , '/' , '-' , '\\' };
  #endif

  	out_fd = ksys_open("/dev/ram", O_RDWR, 0);

  	if (out_fd < 0)
  		goto out;

  	in_fd = ksys_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.

  	 */

  	if (ksys_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)
  ",
  		       nblocks, rd_blocks);
  		goto done;
  	}

  	/*
  	 * OK, time to copy in the data
  	 */

  	if (ksys_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
  ");
  		goto done;
  	}
  
  	buf = kmalloc(BLOCK_SIZE, GFP_KERNEL);

  	if (!buf) {

  		printk(KERN_ERR "RAMDISK: could not allocate buffer
  ");
  		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)) {

  			pr_cont("done disk #%d.
  ", disk++);

  			rotate = 0;

  			if (ksys_close(in_fd)) {

  				printk("Error closing the disk.
  ");
  				goto noclose_input;
  			}
  			change_floppy("disk #%d", disk);

  			in_fd = ksys_open(from, O_RDONLY, 0);

  			if (in_fd < 0)  {
  				printk("Error opening disk.
  ");
  				goto noclose_input;
  			}
  			printk("Loading disk #%d... ", disk);
  		}

  		ksys_read(in_fd, buf, BLOCK_SIZE);

  		ksys_write(out_fd, buf, BLOCK_SIZE);

  #if !defined(CONFIG_S390)

  		if (!(i % 16)) {

  			pr_cont("%c\b", rotator[rotate & 0x3]);

  			rotate++;
  		}
  #endif
  	}

  	pr_cont("done.
  ");

  
  successful_load:
  	res = 1;
  done:

  	ksys_close(in_fd);

  noclose_input:

  	ksys_close(out_fd);

  out:
  	kfree(buf);

  	ksys_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");
  }

  static int exit_code;

  static int decompress_error;

  static int crd_infd, crd_outfd;

  static long __init compr_fill(void *buf, unsigned long len)

  {

  	long r = ksys_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 long __init compr_flush(void *window, unsigned long outcnt)

  {

  	long written = ksys_write(crd_outfd, window, outcnt);

  	if (written != outcnt) {
  		if (decompress_error == 0)
  			printk(KERN_ERR

  			       "RAMDISK: incomplete write (%ld != %ld)
  ",

  			       written, outcnt);
  		decompress_error = 1;
  		return -1;
  	}
  	return outcnt;

  }
  
  static void __init error(char *x)
  {
  	printk(KERN_ERR "%s
  ", 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;

  
  	if (!deco) {
  		pr_emerg("Invalid ramdisk decompression routine.  "
  			 "Select appropriate config option.
  ");
  		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;
  }