1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/kernel.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>
12 #include "do_mounts.h"
13 #include "../fs/squashfs/squashfs_fs.h"
15 #include <linux/decompress/generic.h>
17 static struct file *in_file, *out_file;
18 static loff_t in_pos, out_pos;
20 static int __init prompt_ramdisk(char *str)
22 pr_warn("ignoring the deprecated prompt_ramdisk= option\n");
25 __setup("prompt_ramdisk=", prompt_ramdisk);
27 int __initdata rd_image_start; /* starting block # of image */
29 static int __init ramdisk_start_setup(char *str)
31 rd_image_start = simple_strtol(str,NULL,0);
34 __setup("ramdisk_start=", ramdisk_start_setup);
36 static int __init crd_load(decompress_fn deco);
39 * This routine tries to find a RAM disk image to load, and returns the
40 * number of blocks to read for a non-compressed image, 0 if the image
41 * is a compressed image, and -1 if an image with the right magic
42 * numbers could not be found.
44 * We currently check for the following magic numbers:
58 identify_ramdisk_image(struct file *file, loff_t pos,
59 decompress_fn *decompressor)
62 struct minix_super_block *minixsb;
63 struct romfs_super_block *romfsb;
64 struct cramfs_super *cramfsb;
65 struct squashfs_super_block *squashfsb;
68 const char *compress_name;
70 int start_block = rd_image_start;
72 buf = kmalloc(size, GFP_KERNEL);
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);
83 * Read block 0 to test for compressed kernel
85 pos = start_block * BLOCK_SIZE;
86 kernel_read(file, buf, size, &pos);
88 *decompressor = decompress_method(buf, size, &compress_name);
90 printk(KERN_NOTICE "RAMDISK: %s image found at block %d\n",
91 compress_name, start_block);
94 "RAMDISK: %s decompressor not configured!\n",
100 /* romfs is at block zero too */
101 if (romfsb->word0 == ROMSB_WORD0 &&
102 romfsb->word1 == ROMSB_WORD1) {
104 "RAMDISK: romfs filesystem found at block %d\n",
106 nblocks = (ntohl(romfsb->size)+BLOCK_SIZE-1)>>BLOCK_SIZE_BITS;
110 if (cramfsb->magic == CRAMFS_MAGIC) {
112 "RAMDISK: cramfs filesystem found at block %d\n",
114 nblocks = (cramfsb->size + BLOCK_SIZE - 1) >> BLOCK_SIZE_BITS;
118 /* squashfs is at block zero too */
119 if (le32_to_cpu(squashfsb->s_magic) == SQUASHFS_MAGIC) {
121 "RAMDISK: squashfs filesystem found at block %d\n",
123 nblocks = (le64_to_cpu(squashfsb->bytes_used) + BLOCK_SIZE - 1)
129 * Read 512 bytes further to check if cramfs is padded
131 pos = start_block * BLOCK_SIZE + 0x200;
132 kernel_read(file, buf, size, &pos);
134 if (cramfsb->magic == CRAMFS_MAGIC) {
136 "RAMDISK: cramfs filesystem found at block %d\n",
138 nblocks = (cramfsb->size + BLOCK_SIZE - 1) >> BLOCK_SIZE_BITS;
143 * Read block 1 to test for minix and ext2 superblock
145 pos = (start_block + 1) * BLOCK_SIZE;
146 kernel_read(file, buf, size, &pos);
149 if (minixsb->s_magic == MINIX_SUPER_MAGIC ||
150 minixsb->s_magic == MINIX_SUPER_MAGIC2) {
152 "RAMDISK: Minix filesystem found at block %d\n",
154 nblocks = minixsb->s_nzones << minixsb->s_log_zone_size;
159 n = ext2_image_size(buf);
162 "RAMDISK: ext2 filesystem found at block %d\n",
169 "RAMDISK: Couldn't find valid RAM disk image starting at %d.\n",
177 static unsigned long nr_blocks(struct file *file)
179 struct inode *inode = file->f_mapping->host;
181 if (!S_ISBLK(inode->i_mode))
183 return i_size_read(inode) >> 10;
186 int __init rd_load_image(char *from)
189 unsigned long rd_blocks, devblocks;
192 unsigned short rotate = 0;
193 decompress_fn decompressor = NULL;
194 #if !defined(CONFIG_S390)
195 char rotator[4] = { '|' , '/' , '-' , '\\' };
198 out_file = filp_open("/dev/ram", O_RDWR, 0);
199 if (IS_ERR(out_file))
202 in_file = filp_open(from, O_RDONLY, 0);
206 in_pos = rd_image_start * BLOCK_SIZE;
207 nblocks = identify_ramdisk_image(in_file, in_pos, &decompressor);
212 if (crd_load(decompressor) == 0)
213 goto successful_load;
218 * NOTE NOTE: nblocks is not actually blocks but
219 * the number of kibibytes of data to load into a ramdisk.
221 rd_blocks = nr_blocks(out_file);
222 if (nblocks > rd_blocks) {
223 printk("RAMDISK: image too big! (%dKiB/%ldKiB)\n",
229 * OK, time to copy in the data
231 if (strcmp(from, "/initrd.image") == 0)
234 devblocks = nr_blocks(in_file);
236 if (devblocks == 0) {
237 printk(KERN_ERR "RAMDISK: could not determine device size\n");
241 buf = kmalloc(BLOCK_SIZE, GFP_KERNEL);
243 printk(KERN_ERR "RAMDISK: could not allocate buffer\n");
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");
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)
260 pr_cont("%c\b", rotator[rotate & 0x3]);
275 ksys_unlink("/dev/ram");
279 int __init rd_load_disk(int n)
281 create_dev("/dev/root", ROOT_DEV);
282 create_dev("/dev/ram", MKDEV(RAMDISK_MAJOR, n));
283 return rd_load_image("/dev/root");
286 static int exit_code;
287 static int decompress_error;
289 static long __init compr_fill(void *buf, unsigned long len)
291 long r = kernel_read(in_file, buf, len, &in_pos);
293 printk(KERN_ERR "RAMDISK: error while reading compressed data");
295 printk(KERN_ERR "RAMDISK: EOF while reading compressed data");
299 static long __init compr_flush(void *window, unsigned long outcnt)
301 long written = kernel_write(out_file, window, outcnt, &out_pos);
302 if (written != outcnt) {
303 if (decompress_error == 0)
305 "RAMDISK: incomplete write (%ld != %ld)\n",
307 decompress_error = 1;
313 static void __init error(char *x)
315 printk(KERN_ERR "%s\n", x);
317 decompress_error = 1;
320 static int __init crd_load(decompress_fn deco)
325 pr_emerg("Invalid ramdisk decompression routine. "
326 "Select appropriate config option.\n");
327 panic("Could not decompress initial ramdisk image.");
330 result = deco(NULL, 0, compr_fill, compr_flush, NULL, NULL, error);
331 if (decompress_error)