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Linux/init/do_mounts_rd.c

  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 <uapi/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 
 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 
 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  *      bzip2
 61  *      lzma
 62  *      xz
 63  *      lzo
 64  *      lz4
 65  */
 66 static int __init
 67 identify_ramdisk_image(int fd, int start_block, decompress_fn *decompressor)
 68 {
 69         const int size = 512;
 70         struct minix_super_block *minixsb;
 71         struct romfs_super_block *romfsb;
 72         struct cramfs_super *cramfsb;
 73         struct squashfs_super_block *squashfsb;
 74         int nblocks = -1;
 75         unsigned char *buf;
 76         const char *compress_name;
 77         unsigned long n;
 78 
 79         buf = kmalloc(size, GFP_KERNEL);
 80         if (!buf)
 81                 return -ENOMEM;
 82 
 83         minixsb = (struct minix_super_block *) buf;
 84         romfsb = (struct romfs_super_block *) buf;
 85         cramfsb = (struct cramfs_super *) buf;
 86         squashfsb = (struct squashfs_super_block *) buf;
 87         memset(buf, 0xe5, size);
 88 
 89         /*
 90          * Read block 0 to test for compressed kernel
 91          */
 92         sys_lseek(fd, start_block * BLOCK_SIZE, 0);
 93         sys_read(fd, buf, size);
 94 
 95         *decompressor = decompress_method(buf, size, &compress_name);
 96         if (compress_name) {
 97                 printk(KERN_NOTICE "RAMDISK: %s image found at block %d\n",
 98                        compress_name, start_block);
 99                 if (!*decompressor)
100                         printk(KERN_EMERG
101                                "RAMDISK: %s decompressor not configured!\n",
102                                compress_name);
103                 nblocks = 0;
104                 goto done;
105         }
106 
107         /* romfs is at block zero too */
108         if (romfsb->word0 == ROMSB_WORD0 &&
109             romfsb->word1 == ROMSB_WORD1) {
110                 printk(KERN_NOTICE
111                        "RAMDISK: romfs filesystem found at block %d\n",
112                        start_block);
113                 nblocks = (ntohl(romfsb->size)+BLOCK_SIZE-1)>>BLOCK_SIZE_BITS;
114                 goto done;
115         }
116 
117         if (cramfsb->magic == CRAMFS_MAGIC) {
118                 printk(KERN_NOTICE
119                        "RAMDISK: cramfs filesystem found at block %d\n",
120                        start_block);
121                 nblocks = (cramfsb->size + BLOCK_SIZE - 1) >> BLOCK_SIZE_BITS;
122                 goto done;
123         }
124 
125         /* squashfs is at block zero too */
126         if (le32_to_cpu(squashfsb->s_magic) == SQUASHFS_MAGIC) {
127                 printk(KERN_NOTICE
128                        "RAMDISK: squashfs filesystem found at block %d\n",
129                        start_block);
130                 nblocks = (le64_to_cpu(squashfsb->bytes_used) + BLOCK_SIZE - 1)
131                          >> BLOCK_SIZE_BITS;
132                 goto done;
133         }
134 
135         /*
136          * Read 512 bytes further to check if cramfs is padded
137          */
138         sys_lseek(fd, start_block * BLOCK_SIZE + 0x200, 0);
139         sys_read(fd, buf, size);
140 
141         if (cramfsb->magic == CRAMFS_MAGIC) {
142                 printk(KERN_NOTICE
143                        "RAMDISK: cramfs filesystem found at block %d\n",
144                        start_block);
145                 nblocks = (cramfsb->size + BLOCK_SIZE - 1) >> BLOCK_SIZE_BITS;
146                 goto done;
147         }
148 
149         /*
150          * Read block 1 to test for minix and ext2 superblock
151          */
152         sys_lseek(fd, (start_block+1) * BLOCK_SIZE, 0);
153         sys_read(fd, buf, size);
154 
155         /* Try minix */
156         if (minixsb->s_magic == MINIX_SUPER_MAGIC ||
157             minixsb->s_magic == MINIX_SUPER_MAGIC2) {
158                 printk(KERN_NOTICE
159                        "RAMDISK: Minix filesystem found at block %d\n",
160                        start_block);
161                 nblocks = minixsb->s_nzones << minixsb->s_log_zone_size;
162                 goto done;
163         }
164 
165         /* Try ext2 */
166         n = ext2_image_size(buf);
167         if (n) {
168                 printk(KERN_NOTICE
169                        "RAMDISK: ext2 filesystem found at block %d\n",
170                        start_block);
171                 nblocks = n;
172                 goto done;
173         }
174 
175         printk(KERN_NOTICE
176                "RAMDISK: Couldn't find valid RAM disk image starting at %d.\n",
177                start_block);
178 
179 done:
180         sys_lseek(fd, start_block * BLOCK_SIZE, 0);
181         kfree(buf);
182         return nblocks;
183 }
184 
185 int __init rd_load_image(char *from)
186 {
187         int res = 0;
188         int in_fd, out_fd;
189         unsigned long rd_blocks, devblocks;
190         int nblocks, i, disk;
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_fd = sys_open("/dev/ram", O_RDWR, 0);
199         if (out_fd < 0)
200                 goto out;
201 
202         in_fd = sys_open(from, O_RDONLY, 0);
203         if (in_fd < 0)
204                 goto noclose_input;
205 
206         nblocks = identify_ramdisk_image(in_fd, rd_image_start, &decompressor);
207         if (nblocks < 0)
208                 goto done;
209 
210         if (nblocks == 0) {
211                 if (crd_load(in_fd, out_fd, decompressor) == 0)
212                         goto successful_load;
213                 goto done;
214         }
215 
216         /*
217          * NOTE NOTE: nblocks is not actually blocks but
218          * the number of kibibytes of data to load into a ramdisk.
219          */
220         if (sys_ioctl(out_fd, BLKGETSIZE, (unsigned long)&rd_blocks) < 0)
221                 rd_blocks = 0;
222         else
223                 rd_blocks >>= 1;
224 
225         if (nblocks > rd_blocks) {
226                 printk("RAMDISK: image too big! (%dKiB/%ldKiB)\n",
227                        nblocks, rd_blocks);
228                 goto done;
229         }
230 
231         /*
232          * OK, time to copy in the data
233          */
234         if (sys_ioctl(in_fd, BLKGETSIZE, (unsigned long)&devblocks) < 0)
235                 devblocks = 0;
236         else
237                 devblocks >>= 1;
238 
239         if (strcmp(from, "/initrd.image") == 0)
240                 devblocks = nblocks;
241 
242         if (devblocks == 0) {
243                 printk(KERN_ERR "RAMDISK: could not determine device size\n");
244                 goto done;
245         }
246 
247         buf = kmalloc(BLOCK_SIZE, GFP_KERNEL);
248         if (!buf) {
249                 printk(KERN_ERR "RAMDISK: could not allocate buffer\n");
250                 goto done;
251         }
252 
253         printk(KERN_NOTICE "RAMDISK: Loading %dKiB [%ld disk%s] into ram disk... ",
254                 nblocks, ((nblocks-1)/devblocks)+1, nblocks>devblocks ? "s" : "");
255         for (i = 0, disk = 1; i < nblocks; i++) {
256                 if (i && (i % devblocks == 0)) {
257                         printk("done disk #%d.\n", disk++);
258                         rotate = 0;
259                         if (sys_close(in_fd)) {
260                                 printk("Error closing the disk.\n");
261                                 goto noclose_input;
262                         }
263                         change_floppy("disk #%d", disk);
264                         in_fd = sys_open(from, O_RDONLY, 0);
265                         if (in_fd < 0)  {
266                                 printk("Error opening disk.\n");
267                                 goto noclose_input;
268                         }
269                         printk("Loading disk #%d... ", disk);
270                 }
271                 sys_read(in_fd, buf, BLOCK_SIZE);
272                 sys_write(out_fd, buf, BLOCK_SIZE);
273 #if !defined(CONFIG_S390)
274                 if (!(i % 16)) {
275                         pr_cont("%c\b", rotator[rotate & 0x3]);
276                         rotate++;
277                 }
278 #endif
279         }
280         printk("done.\n");
281 
282 successful_load:
283         res = 1;
284 done:
285         sys_close(in_fd);
286 noclose_input:
287         sys_close(out_fd);
288 out:
289         kfree(buf);
290         sys_unlink("/dev/ram");
291         return res;
292 }
293 
294 int __init rd_load_disk(int n)
295 {
296         if (rd_prompt)
297                 change_floppy("root floppy disk to be loaded into RAM disk");
298         create_dev("/dev/root", ROOT_DEV);
299         create_dev("/dev/ram", MKDEV(RAMDISK_MAJOR, n));
300         return rd_load_image("/dev/root");
301 }
302 
303 static int exit_code;
304 static int decompress_error;
305 static int crd_infd, crd_outfd;
306 
307 static long __init compr_fill(void *buf, unsigned long len)
308 {
309         long r = sys_read(crd_infd, buf, len);
310         if (r < 0)
311                 printk(KERN_ERR "RAMDISK: error while reading compressed data");
312         else if (r == 0)
313                 printk(KERN_ERR "RAMDISK: EOF while reading compressed data");
314         return r;
315 }
316 
317 static long __init compr_flush(void *window, unsigned long outcnt)
318 {
319         long written = sys_write(crd_outfd, window, outcnt);
320         if (written != outcnt) {
321                 if (decompress_error == 0)
322                         printk(KERN_ERR
323                                "RAMDISK: incomplete write (%ld != %ld)\n",
324                                written, outcnt);
325                 decompress_error = 1;
326                 return -1;
327         }
328         return outcnt;
329 }
330 
331 static void __init error(char *x)
332 {
333         printk(KERN_ERR "%s\n", x);
334         exit_code = 1;
335         decompress_error = 1;
336 }
337 
338 static int __init crd_load(int in_fd, int out_fd, decompress_fn deco)
339 {
340         int result;
341         crd_infd = in_fd;
342         crd_outfd = out_fd;
343 
344         if (!deco) {
345                 pr_emerg("Invalid ramdisk decompression routine.  "
346                          "Select appropriate config option.\n");
347                 panic("Could not decompress initial ramdisk image.");
348         }
349 
350         result = deco(NULL, 0, compr_fill, compr_flush, NULL, NULL, error);
351         if (decompress_error)
352                 result = 1;
353         return result;
354 }
355 

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