335 lines · c
1// SPDX-License-Identifier: GPL-2.02#include <linux/kernel.h>3#include <linux/fs.h>4#include <linux/minix_fs.h>5#include <linux/ext2_fs.h>6#include <linux/romfs_fs.h>7#include <uapi/linux/cramfs_fs.h>8#include <linux/initrd.h>9#include <linux/string.h>10#include <linux/slab.h>11 12#include "do_mounts.h"13#include "../fs/squashfs/squashfs_fs.h"14 15#include <linux/decompress/generic.h>16 17static struct file *in_file, *out_file;18static loff_t in_pos, out_pos;19 20static int __init prompt_ramdisk(char *str)21{22 pr_warn("ignoring the deprecated prompt_ramdisk= option\n");23 return 1;24}25__setup("prompt_ramdisk=", prompt_ramdisk);26 27int __initdata rd_image_start; /* starting block # of image */28 29static int __init ramdisk_start_setup(char *str)30{31 rd_image_start = simple_strtol(str,NULL,0);32 return 1;33}34__setup("ramdisk_start=", ramdisk_start_setup);35 36static int __init crd_load(decompress_fn deco);37 38/*39 * This routine tries to find a RAM disk image to load, and returns the40 * number of blocks to read for a non-compressed image, 0 if the image41 * is a compressed image, and -1 if an image with the right magic42 * numbers could not be found.43 *44 * We currently check for the following magic numbers:45 * minix46 * ext247 * romfs48 * cramfs49 * squashfs50 * gzip51 * bzip252 * lzma53 * xz54 * lzo55 * lz456 */57static int __init58identify_ramdisk_image(struct file *file, loff_t pos,59 decompress_fn *decompressor)60{61 const int size = 512;62 struct minix_super_block *minixsb;63 struct romfs_super_block *romfsb;64 struct cramfs_super *cramfsb;65 struct squashfs_super_block *squashfsb;66 int nblocks = -1;67 unsigned char *buf;68 const char *compress_name;69 unsigned long n;70 int start_block = rd_image_start;71 72 buf = kmalloc(size, GFP_KERNEL);73 if (!buf)74 return -ENOMEM;75 76 minixsb = (struct minix_super_block *) buf;77 romfsb = (struct romfs_super_block *) buf;78 cramfsb = (struct cramfs_super *) buf;79 squashfsb = (struct squashfs_super_block *) buf;80 memset(buf, 0xe5, size);81 82 /*83 * Read block 0 to test for compressed kernel84 */85 pos = start_block * BLOCK_SIZE;86 kernel_read(file, buf, size, &pos);87 88 *decompressor = decompress_method(buf, size, &compress_name);89 if (compress_name) {90 printk(KERN_NOTICE "RAMDISK: %s image found at block %d\n",91 compress_name, start_block);92 if (!*decompressor)93 printk(KERN_EMERG94 "RAMDISK: %s decompressor not configured!\n",95 compress_name);96 nblocks = 0;97 goto done;98 }99 100 /* romfs is at block zero too */101 if (romfsb->word0 == ROMSB_WORD0 &&102 romfsb->word1 == ROMSB_WORD1) {103 printk(KERN_NOTICE104 "RAMDISK: romfs filesystem found at block %d\n",105 start_block);106 nblocks = (ntohl(romfsb->size)+BLOCK_SIZE-1)>>BLOCK_SIZE_BITS;107 goto done;108 }109 110 if (cramfsb->magic == CRAMFS_MAGIC) {111 printk(KERN_NOTICE112 "RAMDISK: cramfs filesystem found at block %d\n",113 start_block);114 nblocks = (cramfsb->size + BLOCK_SIZE - 1) >> BLOCK_SIZE_BITS;115 goto done;116 }117 118 /* squashfs is at block zero too */119 if (le32_to_cpu(squashfsb->s_magic) == SQUASHFS_MAGIC) {120 printk(KERN_NOTICE121 "RAMDISK: squashfs filesystem found at block %d\n",122 start_block);123 nblocks = (le64_to_cpu(squashfsb->bytes_used) + BLOCK_SIZE - 1)124 >> BLOCK_SIZE_BITS;125 goto done;126 }127 128 /*129 * Read 512 bytes further to check if cramfs is padded130 */131 pos = start_block * BLOCK_SIZE + 0x200;132 kernel_read(file, buf, size, &pos);133 134 if (cramfsb->magic == CRAMFS_MAGIC) {135 printk(KERN_NOTICE136 "RAMDISK: cramfs filesystem found at block %d\n",137 start_block);138 nblocks = (cramfsb->size + BLOCK_SIZE - 1) >> BLOCK_SIZE_BITS;139 goto done;140 }141 142 /*143 * Read block 1 to test for minix and ext2 superblock144 */145 pos = (start_block + 1) * BLOCK_SIZE;146 kernel_read(file, buf, size, &pos);147 148 /* Try minix */149 if (minixsb->s_magic == MINIX_SUPER_MAGIC ||150 minixsb->s_magic == MINIX_SUPER_MAGIC2) {151 printk(KERN_NOTICE152 "RAMDISK: Minix filesystem found at block %d\n",153 start_block);154 nblocks = minixsb->s_nzones << minixsb->s_log_zone_size;155 goto done;156 }157 158 /* Try ext2 */159 n = ext2_image_size(buf);160 if (n) {161 printk(KERN_NOTICE162 "RAMDISK: ext2 filesystem found at block %d\n",163 start_block);164 nblocks = n;165 goto done;166 }167 168 printk(KERN_NOTICE169 "RAMDISK: Couldn't find valid RAM disk image starting at %d.\n",170 start_block);171 172done:173 kfree(buf);174 return nblocks;175}176 177static unsigned long nr_blocks(struct file *file)178{179 struct inode *inode = file->f_mapping->host;180 181 if (!S_ISBLK(inode->i_mode))182 return 0;183 return i_size_read(inode) >> 10;184}185 186int __init rd_load_image(char *from)187{188 int res = 0;189 unsigned long rd_blocks, devblocks;190 int nblocks, i;191 char *buf = NULL;192 unsigned short rotate = 0;193 decompress_fn decompressor = NULL;194#if !defined(CONFIG_S390)195 char rotator[4] = { '|' , '/' , '-' , '\\' };196#endif197 198 out_file = filp_open("/dev/ram", O_RDWR, 0);199 if (IS_ERR(out_file))200 goto out;201 202 in_file = filp_open(from, O_RDONLY, 0);203 if (IS_ERR(in_file))204 goto noclose_input;205 206 in_pos = rd_image_start * BLOCK_SIZE;207 nblocks = identify_ramdisk_image(in_file, in_pos, &decompressor);208 if (nblocks < 0)209 goto done;210 211 if (nblocks == 0) {212 if (crd_load(decompressor) == 0)213 goto successful_load;214 goto done;215 }216 217 /*218 * NOTE NOTE: nblocks is not actually blocks but219 * the number of kibibytes of data to load into a ramdisk.220 */221 rd_blocks = nr_blocks(out_file);222 if (nblocks > rd_blocks) {223 printk("RAMDISK: image too big! (%dKiB/%ldKiB)\n",224 nblocks, rd_blocks);225 goto done;226 }227 228 /*229 * OK, time to copy in the data230 */231 if (strcmp(from, "/initrd.image") == 0)232 devblocks = nblocks;233 else234 devblocks = nr_blocks(in_file);235 236 if (devblocks == 0) {237 printk(KERN_ERR "RAMDISK: could not determine device size\n");238 goto done;239 }240 241 buf = kmalloc(BLOCK_SIZE, GFP_KERNEL);242 if (!buf) {243 printk(KERN_ERR "RAMDISK: could not allocate buffer\n");244 goto done;245 }246 247 printk(KERN_NOTICE "RAMDISK: Loading %dKiB [%ld disk%s] into ram disk... ",248 nblocks, ((nblocks-1)/devblocks)+1, nblocks>devblocks ? "s" : "");249 for (i = 0; i < nblocks; i++) {250 if (i && (i % devblocks == 0)) {251 pr_cont("done disk #1.\n");252 rotate = 0;253 fput(in_file);254 break;255 }256 kernel_read(in_file, buf, BLOCK_SIZE, &in_pos);257 kernel_write(out_file, buf, BLOCK_SIZE, &out_pos);258#if !defined(CONFIG_S390)259 if (!(i % 16)) {260 pr_cont("%c\b", rotator[rotate & 0x3]);261 rotate++;262 }263#endif264 }265 pr_cont("done.\n");266 267successful_load:268 res = 1;269done:270 fput(in_file);271noclose_input:272 fput(out_file);273out:274 kfree(buf);275 init_unlink("/dev/ram");276 return res;277}278 279int __init rd_load_disk(int n)280{281 create_dev("/dev/root", ROOT_DEV);282 create_dev("/dev/ram", MKDEV(RAMDISK_MAJOR, n));283 return rd_load_image("/dev/root");284}285 286static int exit_code;287static int decompress_error;288 289static long __init compr_fill(void *buf, unsigned long len)290{291 long r = kernel_read(in_file, buf, len, &in_pos);292 if (r < 0)293 printk(KERN_ERR "RAMDISK: error while reading compressed data");294 else if (r == 0)295 printk(KERN_ERR "RAMDISK: EOF while reading compressed data");296 return r;297}298 299static long __init compr_flush(void *window, unsigned long outcnt)300{301 long written = kernel_write(out_file, window, outcnt, &out_pos);302 if (written != outcnt) {303 if (decompress_error == 0)304 printk(KERN_ERR305 "RAMDISK: incomplete write (%ld != %ld)\n",306 written, outcnt);307 decompress_error = 1;308 return -1;309 }310 return outcnt;311}312 313static void __init error(char *x)314{315 printk(KERN_ERR "%s\n", x);316 exit_code = 1;317 decompress_error = 1;318}319 320static int __init crd_load(decompress_fn deco)321{322 int result;323 324 if (!deco) {325 pr_emerg("Invalid ramdisk decompression routine. "326 "Select appropriate config option.\n");327 panic("Could not decompress initial ramdisk image.");328 }329 330 result = deco(NULL, 0, compr_fill, compr_flush, NULL, NULL, error);331 if (decompress_error)332 result = 1;333 return result;334}335