1 /*
2 * Many of the syscalls used in this file expect some of the arguments
3 * to be __user pointers not __kernel pointers. To limit the sparse
4 * noise, turn off sparse checking for this file.
5 */
6 #ifdef __CHECKER__
7 #undef __CHECKER__
8 #warning "Sparse checking disabled for this file"
9 #endif
10
11 #include <linux/kernel.h>
12 #include <linux/fs.h>
13 #include <linux/minix_fs.h>
14 #include <linux/ext2_fs.h>
15 #include <linux/romfs_fs.h>
16 #include <linux/cramfs_fs.h>
17 #include <linux/initrd.h>
18 #include <linux/string.h>
19 #include <linux/slab.h>
20
21 #include "do_mounts.h"
22 #include "../fs/squashfs/squashfs_fs.h"
23
24 #include <linux/decompress/generic.h>
25
26
27 int __initdata rd_prompt = 1;/* 1 = prompt for RAM disk, 0 = don't prompt */
28
prompt_ramdisk(char * str)29 static int __init prompt_ramdisk(char *str)
30 {
31 rd_prompt = simple_strtol(str,NULL,0) & 1;
32 return 1;
33 }
34 __setup("prompt_ramdisk=", prompt_ramdisk);
35
36 int __initdata rd_image_start; /* starting block # of image */
37
ramdisk_start_setup(char * str)38 static int __init ramdisk_start_setup(char *str)
39 {
40 rd_image_start = simple_strtol(str,NULL,0);
41 return 1;
42 }
43 __setup("ramdisk_start=", ramdisk_start_setup);
44
45 static int __init crd_load(int in_fd, int out_fd, decompress_fn deco);
46
47 /*
48 * This routine tries to find a RAM disk image to load, and returns the
49 * number of blocks to read for a non-compressed image, 0 if the image
50 * is a compressed image, and -1 if an image with the right magic
51 * numbers could not be found.
52 *
53 * We currently check for the following magic numbers:
54 * minix
55 * ext2
56 * romfs
57 * cramfs
58 * squashfs
59 * gzip
60 */
61 static int __init
identify_ramdisk_image(int fd,int start_block,decompress_fn * decompressor)62 identify_ramdisk_image(int fd, int start_block, decompress_fn *decompressor)
63 {
64 const int size = 512;
65 struct minix_super_block *minixsb;
66 struct romfs_super_block *romfsb;
67 struct cramfs_super *cramfsb;
68 struct squashfs_super_block *squashfsb;
69 int nblocks = -1;
70 unsigned char *buf;
71 const char *compress_name;
72 unsigned long n;
73
74 buf = kmalloc(size, GFP_KERNEL);
75 if (!buf)
76 return -ENOMEM;
77
78 minixsb = (struct minix_super_block *) buf;
79 romfsb = (struct romfs_super_block *) buf;
80 cramfsb = (struct cramfs_super *) buf;
81 squashfsb = (struct squashfs_super_block *) buf;
82 memset(buf, 0xe5, size);
83
84 /*
85 * Read block 0 to test for compressed kernel
86 */
87 sys_lseek(fd, start_block * BLOCK_SIZE, 0);
88 sys_read(fd, buf, size);
89
90 *decompressor = decompress_method(buf, size, &compress_name);
91 if (compress_name) {
92 printk(KERN_NOTICE "RAMDISK: %s image found at block %d\n",
93 compress_name, start_block);
94 if (!*decompressor)
95 printk(KERN_EMERG
96 "RAMDISK: %s decompressor not configured!\n",
97 compress_name);
98 nblocks = 0;
99 goto done;
100 }
101
102 /* romfs is at block zero too */
103 if (romfsb->word0 == ROMSB_WORD0 &&
104 romfsb->word1 == ROMSB_WORD1) {
105 printk(KERN_NOTICE
106 "RAMDISK: romfs filesystem found at block %d\n",
107 start_block);
108 nblocks = (ntohl(romfsb->size)+BLOCK_SIZE-1)>>BLOCK_SIZE_BITS;
109 goto done;
110 }
111
112 if (cramfsb->magic == CRAMFS_MAGIC) {
113 printk(KERN_NOTICE
114 "RAMDISK: cramfs filesystem found at block %d\n",
115 start_block);
116 nblocks = (cramfsb->size + BLOCK_SIZE - 1) >> BLOCK_SIZE_BITS;
117 goto done;
118 }
119
120 /* squashfs is at block zero too */
121 if (le32_to_cpu(squashfsb->s_magic) == SQUASHFS_MAGIC) {
122 printk(KERN_NOTICE
123 "RAMDISK: squashfs filesystem found at block %d\n",
124 start_block);
125 nblocks = (le64_to_cpu(squashfsb->bytes_used) + BLOCK_SIZE - 1)
126 >> BLOCK_SIZE_BITS;
127 goto done;
128 }
129
130 /*
131 * Read 512 bytes further to check if cramfs is padded
132 */
133 sys_lseek(fd, start_block * BLOCK_SIZE + 0x200, 0);
134 sys_read(fd, buf, size);
135
136 if (cramfsb->magic == CRAMFS_MAGIC) {
137 printk(KERN_NOTICE
138 "RAMDISK: cramfs filesystem found at block %d\n",
139 start_block);
140 nblocks = (cramfsb->size + BLOCK_SIZE - 1) >> BLOCK_SIZE_BITS;
141 goto done;
142 }
143
144 /*
145 * Read block 1 to test for minix and ext2 superblock
146 */
147 sys_lseek(fd, (start_block+1) * BLOCK_SIZE, 0);
148 sys_read(fd, buf, size);
149
150 /* Try minix */
151 if (minixsb->s_magic == MINIX_SUPER_MAGIC ||
152 minixsb->s_magic == MINIX_SUPER_MAGIC2) {
153 printk(KERN_NOTICE
154 "RAMDISK: Minix filesystem found at block %d\n",
155 start_block);
156 nblocks = minixsb->s_nzones << minixsb->s_log_zone_size;
157 goto done;
158 }
159
160 /* Try ext2 */
161 n = ext2_image_size(buf);
162 if (n) {
163 printk(KERN_NOTICE
164 "RAMDISK: ext2 filesystem found at block %d\n",
165 start_block);
166 nblocks = n;
167 goto done;
168 }
169
170 printk(KERN_NOTICE
171 "RAMDISK: Couldn't find valid RAM disk image starting at %d.\n",
172 start_block);
173
174 done:
175 sys_lseek(fd, start_block * BLOCK_SIZE, 0);
176 kfree(buf);
177 return nblocks;
178 }
179
rd_load_image(char * from)180 int __init rd_load_image(char *from)
181 {
182 int res = 0;
183 int in_fd, out_fd;
184 unsigned long rd_blocks, devblocks;
185 int nblocks, i, disk;
186 char *buf = NULL;
187 unsigned short rotate = 0;
188 decompress_fn decompressor = NULL;
189 #if !defined(CONFIG_S390)
190 char rotator[4] = { '|' , '/' , '-' , '\\' };
191 #endif
192
193 out_fd = sys_open("/dev/ram", O_RDWR, 0);
194 if (out_fd < 0)
195 goto out;
196
197 in_fd = sys_open(from, O_RDONLY, 0);
198 if (in_fd < 0)
199 goto noclose_input;
200
201 nblocks = identify_ramdisk_image(in_fd, rd_image_start, &decompressor);
202 if (nblocks < 0)
203 goto done;
204
205 if (nblocks == 0) {
206 if (crd_load(in_fd, out_fd, decompressor) == 0)
207 goto successful_load;
208 goto done;
209 }
210
211 /*
212 * NOTE NOTE: nblocks is not actually blocks but
213 * the number of kibibytes of data to load into a ramdisk.
214 * So any ramdisk block size that is a multiple of 1KiB should
215 * work when the appropriate ramdisk_blocksize is specified
216 * on the command line.
217 *
218 * The default ramdisk_blocksize is 1KiB and it is generally
219 * silly to use anything else, so make sure to use 1KiB
220 * blocksize while generating ext2fs ramdisk-images.
221 */
222 if (sys_ioctl(out_fd, BLKGETSIZE, (unsigned long)&rd_blocks) < 0)
223 rd_blocks = 0;
224 else
225 rd_blocks >>= 1;
226
227 if (nblocks > rd_blocks) {
228 printk("RAMDISK: image too big! (%dKiB/%ldKiB)\n",
229 nblocks, rd_blocks);
230 goto done;
231 }
232
233 /*
234 * OK, time to copy in the data
235 */
236 if (sys_ioctl(in_fd, BLKGETSIZE, (unsigned long)&devblocks) < 0)
237 devblocks = 0;
238 else
239 devblocks >>= 1;
240
241 if (strcmp(from, "/initrd.image") == 0)
242 devblocks = nblocks;
243
244 if (devblocks == 0) {
245 printk(KERN_ERR "RAMDISK: could not determine device size\n");
246 goto done;
247 }
248
249 buf = kmalloc(BLOCK_SIZE, GFP_KERNEL);
250 if (!buf) {
251 printk(KERN_ERR "RAMDISK: could not allocate buffer\n");
252 goto done;
253 }
254
255 printk(KERN_NOTICE "RAMDISK: Loading %dKiB [%ld disk%s] into ram disk... ",
256 nblocks, ((nblocks-1)/devblocks)+1, nblocks>devblocks ? "s" : "");
257 for (i = 0, disk = 1; i < nblocks; i++) {
258 if (i && (i % devblocks == 0)) {
259 printk("done disk #%d.\n", disk++);
260 rotate = 0;
261 if (sys_close(in_fd)) {
262 printk("Error closing the disk.\n");
263 goto noclose_input;
264 }
265 change_floppy("disk #%d", disk);
266 in_fd = sys_open(from, O_RDONLY, 0);
267 if (in_fd < 0) {
268 printk("Error opening disk.\n");
269 goto noclose_input;
270 }
271 printk("Loading disk #%d... ", disk);
272 }
273 sys_read(in_fd, buf, BLOCK_SIZE);
274 sys_write(out_fd, buf, BLOCK_SIZE);
275 #if !defined(CONFIG_S390)
276 if (!(i % 16)) {
277 printk("%c\b", rotator[rotate & 0x3]);
278 rotate++;
279 }
280 #endif
281 }
282 printk("done.\n");
283
284 successful_load:
285 res = 1;
286 done:
287 sys_close(in_fd);
288 noclose_input:
289 sys_close(out_fd);
290 out:
291 kfree(buf);
292 sys_unlink("/dev/ram");
293 return res;
294 }
295
rd_load_disk(int n)296 int __init rd_load_disk(int n)
297 {
298 if (rd_prompt)
299 change_floppy("root floppy disk to be loaded into RAM disk");
300 create_dev("/dev/root", ROOT_DEV);
301 create_dev("/dev/ram", MKDEV(RAMDISK_MAJOR, n));
302 return rd_load_image("/dev/root");
303 }
304
305 static int exit_code;
306 static int decompress_error;
307 static int crd_infd, crd_outfd;
308
compr_fill(void * buf,unsigned int len)309 static int __init compr_fill(void *buf, unsigned int len)
310 {
311 int r = sys_read(crd_infd, buf, len);
312 if (r < 0)
313 printk(KERN_ERR "RAMDISK: error while reading compressed data");
314 else if (r == 0)
315 printk(KERN_ERR "RAMDISK: EOF while reading compressed data");
316 return r;
317 }
318
compr_flush(void * window,unsigned int outcnt)319 static int __init compr_flush(void *window, unsigned int outcnt)
320 {
321 int written = sys_write(crd_outfd, window, outcnt);
322 if (written != outcnt) {
323 if (decompress_error == 0)
324 printk(KERN_ERR
325 "RAMDISK: incomplete write (%d != %d)\n",
326 written, outcnt);
327 decompress_error = 1;
328 return -1;
329 }
330 return outcnt;
331 }
332
error(char * x)333 static void __init error(char *x)
334 {
335 printk(KERN_ERR "%s\n", x);
336 exit_code = 1;
337 decompress_error = 1;
338 }
339
crd_load(int in_fd,int out_fd,decompress_fn deco)340 static int __init crd_load(int in_fd, int out_fd, decompress_fn deco)
341 {
342 int result;
343 crd_infd = in_fd;
344 crd_outfd = out_fd;
345 result = deco(NULL, 0, compr_fill, compr_flush, NULL, NULL, error);
346 if (decompress_error)
347 result = 1;
348 return result;
349 }
350