/*
 * Many of the syscalls used in this file expect some of the arguments
 * to be __user pointers not __kernel pointers.  To limit the sparse
 * noise, turn off sparse checking for this file.
 */
#ifdef __CHECKER__
#undef __CHECKER__
#warning "Sparse checking disabled for this file"
#endif

#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
 *      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
         */
        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 512 bytes further to check if cramfs is padded
         */
        sys_lseek(fd, start_block * BLOCK_SIZE + 0x200, 0);
        sys_read(fd, buf, size);

        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 */
        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:
        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)
        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, &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)
                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");
}

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;

        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;
}