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
18 int __initdata rd_prompt = 1;/* 1 = prompt for RAM disk, 0 = don't prompt */
19
prompt_ramdisk(char * str)20 static int __init prompt_ramdisk(char *str)
21 {
22 rd_prompt = simple_strtol(str,NULL,0) & 1;
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(int in_fd, int out_fd, 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(int fd,int start_block,decompress_fn * decompressor)58 identify_ramdisk_image(int fd, int start_block, decompress_fn *decompressor)
59 {
60 const int size = 512;
61 struct minix_super_block *minixsb;
62 struct romfs_super_block *romfsb;
63 struct cramfs_super *cramfsb;
64 struct squashfs_super_block *squashfsb;
65 int nblocks = -1;
66 unsigned char *buf;
67 const char *compress_name;
68 unsigned long n;
69
70 buf = kmalloc(size, GFP_KERNEL);
71 if (!buf)
72 return -ENOMEM;
73
74 minixsb = (struct minix_super_block *) buf;
75 romfsb = (struct romfs_super_block *) buf;
76 cramfsb = (struct cramfs_super *) buf;
77 squashfsb = (struct squashfs_super_block *) buf;
78 memset(buf, 0xe5, size);
79
80 /*
81 * Read block 0 to test for compressed kernel
82 */
83 ksys_lseek(fd, start_block * BLOCK_SIZE, 0);
84 ksys_read(fd, buf, size);
85
86 *decompressor = decompress_method(buf, size, &compress_name);
87 if (compress_name) {
88 printk(KERN_NOTICE "RAMDISK: %s image found at block %d\n",
89 compress_name, start_block);
90 if (!*decompressor)
91 printk(KERN_EMERG
92 "RAMDISK: %s decompressor not configured!\n",
93 compress_name);
94 nblocks = 0;
95 goto done;
96 }
97
98 /* romfs is at block zero too */
99 if (romfsb->word0 == ROMSB_WORD0 &&
100 romfsb->word1 == ROMSB_WORD1) {
101 printk(KERN_NOTICE
102 "RAMDISK: romfs filesystem found at block %d\n",
103 start_block);
104 nblocks = (ntohl(romfsb->size)+BLOCK_SIZE-1)>>BLOCK_SIZE_BITS;
105 goto done;
106 }
107
108 if (cramfsb->magic == CRAMFS_MAGIC) {
109 printk(KERN_NOTICE
110 "RAMDISK: cramfs filesystem found at block %d\n",
111 start_block);
112 nblocks = (cramfsb->size + BLOCK_SIZE - 1) >> BLOCK_SIZE_BITS;
113 goto done;
114 }
115
116 /* squashfs is at block zero too */
117 if (le32_to_cpu(squashfsb->s_magic) == SQUASHFS_MAGIC) {
118 printk(KERN_NOTICE
119 "RAMDISK: squashfs filesystem found at block %d\n",
120 start_block);
121 nblocks = (le64_to_cpu(squashfsb->bytes_used) + BLOCK_SIZE - 1)
122 >> BLOCK_SIZE_BITS;
123 goto done;
124 }
125
126 /*
127 * Read 512 bytes further to check if cramfs is padded
128 */
129 ksys_lseek(fd, start_block * BLOCK_SIZE + 0x200, 0);
130 ksys_read(fd, buf, size);
131
132 if (cramfsb->magic == CRAMFS_MAGIC) {
133 printk(KERN_NOTICE
134 "RAMDISK: cramfs filesystem found at block %d\n",
135 start_block);
136 nblocks = (cramfsb->size + BLOCK_SIZE - 1) >> BLOCK_SIZE_BITS;
137 goto done;
138 }
139
140 /*
141 * Read block 1 to test for minix and ext2 superblock
142 */
143 ksys_lseek(fd, (start_block+1) * BLOCK_SIZE, 0);
144 ksys_read(fd, buf, size);
145
146 /* Try minix */
147 if (minixsb->s_magic == MINIX_SUPER_MAGIC ||
148 minixsb->s_magic == MINIX_SUPER_MAGIC2) {
149 printk(KERN_NOTICE
150 "RAMDISK: Minix filesystem found at block %d\n",
151 start_block);
152 nblocks = minixsb->s_nzones << minixsb->s_log_zone_size;
153 goto done;
154 }
155
156 /* Try ext2 */
157 n = ext2_image_size(buf);
158 if (n) {
159 printk(KERN_NOTICE
160 "RAMDISK: ext2 filesystem found at block %d\n",
161 start_block);
162 nblocks = n;
163 goto done;
164 }
165
166 printk(KERN_NOTICE
167 "RAMDISK: Couldn't find valid RAM disk image starting at %d.\n",
168 start_block);
169
170 done:
171 ksys_lseek(fd, start_block * BLOCK_SIZE, 0);
172 kfree(buf);
173 return nblocks;
174 }
175
rd_load_image(char * from)176 int __init rd_load_image(char *from)
177 {
178 int res = 0;
179 int in_fd, out_fd;
180 unsigned long rd_blocks, devblocks;
181 int nblocks, i, disk;
182 char *buf = NULL;
183 unsigned short rotate = 0;
184 decompress_fn decompressor = NULL;
185 #if !defined(CONFIG_S390)
186 char rotator[4] = { '|' , '/' , '-' , '\\' };
187 #endif
188
189 out_fd = ksys_open("/dev/ram", O_RDWR, 0);
190 if (out_fd < 0)
191 goto out;
192
193 in_fd = ksys_open(from, O_RDONLY, 0);
194 if (in_fd < 0)
195 goto noclose_input;
196
197 nblocks = identify_ramdisk_image(in_fd, rd_image_start, &decompressor);
198 if (nblocks < 0)
199 goto done;
200
201 if (nblocks == 0) {
202 if (crd_load(in_fd, out_fd, decompressor) == 0)
203 goto successful_load;
204 goto done;
205 }
206
207 /*
208 * NOTE NOTE: nblocks is not actually blocks but
209 * the number of kibibytes of data to load into a ramdisk.
210 */
211 if (ksys_ioctl(out_fd, BLKGETSIZE, (unsigned long)&rd_blocks) < 0)
212 rd_blocks = 0;
213 else
214 rd_blocks >>= 1;
215
216 if (nblocks > rd_blocks) {
217 printk("RAMDISK: image too big! (%dKiB/%ldKiB)\n",
218 nblocks, rd_blocks);
219 goto done;
220 }
221
222 /*
223 * OK, time to copy in the data
224 */
225 if (ksys_ioctl(in_fd, BLKGETSIZE, (unsigned long)&devblocks) < 0)
226 devblocks = 0;
227 else
228 devblocks >>= 1;
229
230 if (strcmp(from, "/initrd.image") == 0)
231 devblocks = nblocks;
232
233 if (devblocks == 0) {
234 printk(KERN_ERR "RAMDISK: could not determine device size\n");
235 goto done;
236 }
237
238 buf = kmalloc(BLOCK_SIZE, GFP_KERNEL);
239 if (!buf) {
240 printk(KERN_ERR "RAMDISK: could not allocate buffer\n");
241 goto done;
242 }
243
244 printk(KERN_NOTICE "RAMDISK: Loading %dKiB [%ld disk%s] into ram disk... ",
245 nblocks, ((nblocks-1)/devblocks)+1, nblocks>devblocks ? "s" : "");
246 for (i = 0, disk = 1; i < nblocks; i++) {
247 if (i && (i % devblocks == 0)) {
248 pr_cont("done disk #%d.\n", disk++);
249 rotate = 0;
250 if (ksys_close(in_fd)) {
251 printk("Error closing the disk.\n");
252 goto noclose_input;
253 }
254 change_floppy("disk #%d", disk);
255 in_fd = ksys_open(from, O_RDONLY, 0);
256 if (in_fd < 0) {
257 printk("Error opening disk.\n");
258 goto noclose_input;
259 }
260 printk("Loading disk #%d... ", disk);
261 }
262 ksys_read(in_fd, buf, BLOCK_SIZE);
263 ksys_write(out_fd, buf, BLOCK_SIZE);
264 #if !defined(CONFIG_S390)
265 if (!(i % 16)) {
266 pr_cont("%c\b", rotator[rotate & 0x3]);
267 rotate++;
268 }
269 #endif
270 }
271 pr_cont("done.\n");
272
273 successful_load:
274 res = 1;
275 done:
276 ksys_close(in_fd);
277 noclose_input:
278 ksys_close(out_fd);
279 out:
280 kfree(buf);
281 ksys_unlink("/dev/ram");
282 return res;
283 }
284
rd_load_disk(int n)285 int __init rd_load_disk(int n)
286 {
287 if (rd_prompt)
288 change_floppy("root floppy disk to be loaded into RAM disk");
289 create_dev("/dev/root", ROOT_DEV);
290 create_dev("/dev/ram", MKDEV(RAMDISK_MAJOR, n));
291 return rd_load_image("/dev/root");
292 }
293
294 static int exit_code;
295 static int decompress_error;
296 static int crd_infd, crd_outfd;
297
compr_fill(void * buf,unsigned long len)298 static long __init compr_fill(void *buf, unsigned long len)
299 {
300 long r = ksys_read(crd_infd, buf, len);
301 if (r < 0)
302 printk(KERN_ERR "RAMDISK: error while reading compressed data");
303 else if (r == 0)
304 printk(KERN_ERR "RAMDISK: EOF while reading compressed data");
305 return r;
306 }
307
compr_flush(void * window,unsigned long outcnt)308 static long __init compr_flush(void *window, unsigned long outcnt)
309 {
310 long written = ksys_write(crd_outfd, window, outcnt);
311 if (written != outcnt) {
312 if (decompress_error == 0)
313 printk(KERN_ERR
314 "RAMDISK: incomplete write (%ld != %ld)\n",
315 written, outcnt);
316 decompress_error = 1;
317 return -1;
318 }
319 return outcnt;
320 }
321
error(char * x)322 static void __init error(char *x)
323 {
324 printk(KERN_ERR "%s\n", x);
325 exit_code = 1;
326 decompress_error = 1;
327 }
328
crd_load(int in_fd,int out_fd,decompress_fn deco)329 static int __init crd_load(int in_fd, int out_fd, decompress_fn deco)
330 {
331 int result;
332 crd_infd = in_fd;
333 crd_outfd = out_fd;
334
335 if (!deco) {
336 pr_emerg("Invalid ramdisk decompression routine. "
337 "Select appropriate config option.\n");
338 panic("Could not decompress initial ramdisk image.");
339 }
340
341 result = deco(NULL, 0, compr_fill, compr_flush, NULL, NULL, error);
342 if (decompress_error)
343 result = 1;
344 return result;
345 }
346
