1 // SPDX-License-Identifier: GPL-2.0
2 #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
17 static struct file *in_file, *out_file;
18 static loff_t in_pos, out_pos;
19
prompt_ramdisk(char * str)20 static 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
27 int __initdata rd_image_start; /* starting block # of image */
28
ramdisk_start_setup(char * str)29 static 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
36 static int __init crd_load(decompress_fn deco);
37
38 /*
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.
43 *
44 * We currently check for the following magic numbers:
45 * minix
46 * ext2
47 * romfs
48 * cramfs
49 * squashfs
50 * gzip
51 * bzip2
52 * lzma
53 * xz
54 * lzo
55 * lz4
56 */
57 static int __init
identify_ramdisk_image(struct file * file,loff_t pos,decompress_fn * decompressor)58 identify_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 kernel
84 */
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_EMERG
94 "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_NOTICE
104 "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_NOTICE
112 "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_NOTICE
121 "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 padded
130 */
131 pos = start_block * BLOCK_SIZE + 0x200;
132 kernel_read(file, buf, size, &pos);
133
134 if (cramfsb->magic == CRAMFS_MAGIC) {
135 printk(KERN_NOTICE
136 "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 superblock
144 */
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_NOTICE
152 "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_NOTICE
162 "RAMDISK: ext2 filesystem found at block %d\n",
163 start_block);
164 nblocks = n;
165 goto done;
166 }
167
168 printk(KERN_NOTICE
169 "RAMDISK: Couldn't find valid RAM disk image starting at %d.\n",
170 start_block);
171
172 done:
173 kfree(buf);
174 return nblocks;
175 }
176
nr_blocks(struct file * file)177 static 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
rd_load_image(char * from)186 int __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 #endif
197
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 but
219 * 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 data
230 */
231 if (strcmp(from, "/initrd.image") == 0)
232 devblocks = nblocks;
233 else
234 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 #endif
264 }
265 pr_cont("done.\n");
266
267 successful_load:
268 res = 1;
269 done:
270 fput(in_file);
271 noclose_input:
272 fput(out_file);
273 out:
274 kfree(buf);
275 init_unlink("/dev/ram");
276 return res;
277 }
278
rd_load_disk(int n)279 int __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
286 static int exit_code;
287 static int decompress_error;
288
compr_fill(void * buf,unsigned long len)289 static 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
compr_flush(void * window,unsigned long outcnt)299 static 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_ERR
305 "RAMDISK: incomplete write (%ld != %ld)\n",
306 written, outcnt);
307 decompress_error = 1;
308 return -1;
309 }
310 return outcnt;
311 }
312
error(char * x)313 static void __init error(char *x)
314 {
315 printk(KERN_ERR "%s\n", x);
316 exit_code = 1;
317 decompress_error = 1;
318 }
319
crd_load(decompress_fn deco)320 static 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