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
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 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 */
57static int __init
58identify_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
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#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
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_ERR
305			       "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