diff options
Diffstat (limited to 'init/do_mounts_rd.c')
| -rw-r--r-- | init/do_mounts_rd.c | 334 |
1 files changed, 334 insertions, 0 deletions
diff --git a/init/do_mounts_rd.c b/init/do_mounts_rd.c new file mode 100644 index 000000000..ac021ae6e --- /dev/null +++ b/init/do_mounts_rd.c @@ -0,0 +1,334 @@ +// 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> + +static struct file *in_file, *out_file; +static loff_t in_pos, out_pos; + +static int __init prompt_ramdisk(char *str) +{ + pr_warn("ignoring the deprecated prompt_ramdisk= option\n"); + 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(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(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(char *from) +{ + int res = 0; + unsigned long rd_blocks, devblocks; + int nblocks, i; + char *buf = NULL; + unsigned short rotate = 0; + decompress_fn decompressor = NULL; +#if !defined(CONFIG_S390) + char rotator[4] = { '|' , '/' , '-' , '\\' }; +#endif + + out_file = filp_open("/dev/ram", O_RDWR, 0); + if (IS_ERR(out_file)) + goto out; + + in_file = filp_open(from, 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 + */ + if (strcmp(from, "/initrd.image") == 0) + devblocks = nblocks; + else + devblocks = nr_blocks(in_file); + + 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; 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 !defined(CONFIG_S390) + if (!(i % 16)) { + pr_cont("%c\b", rotator[rotate & 0x3]); + rotate++; + } +#endif + } + 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; +} + +int __init rd_load_disk(int n) +{ + 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 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; +} |