Root/init/do_mounts_rd.c

1
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 <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
18int __initdata rd_prompt = 1;/* 1 = prompt for RAM disk, 0 = don't prompt */
19
20static 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
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(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 */
52static int __init
53identify_ramdisk_image(int fd, int start_block, decompress_fn *decompressor)
54{
55    const int size = 512;
56    struct minix_super_block *minixsb;
57    struct ext2_super_block *ext2sb;
58    struct romfs_super_block *romfsb;
59    struct cramfs_super *cramfsb;
60    struct squashfs_super_block *squashfsb;
61    int nblocks = -1;
62    unsigned char *buf;
63    const char *compress_name;
64
65    buf = kmalloc(size, GFP_KERNEL);
66    if (!buf)
67        return -1;
68
69    minixsb = (struct minix_super_block *) buf;
70    ext2sb = (struct ext2_super_block *) buf;
71    romfsb = (struct romfs_super_block *) buf;
72    cramfsb = (struct cramfs_super *) buf;
73    squashfsb = (struct squashfs_super_block *) buf;
74    memset(buf, 0xe5, size);
75
76    /*
77     * Read block 0 to test for compressed kernel
78     */
79    sys_lseek(fd, start_block * BLOCK_SIZE, 0);
80    sys_read(fd, buf, size);
81
82    *decompressor = decompress_method(buf, size, &compress_name);
83    if (compress_name) {
84        printk(KERN_NOTICE "RAMDISK: %s image found at block %d\n",
85               compress_name, start_block);
86        if (!*decompressor)
87            printk(KERN_EMERG
88                   "RAMDISK: %s decompressor not configured!\n",
89                   compress_name);
90        nblocks = 0;
91        goto done;
92    }
93
94    /* romfs is at block zero too */
95    if (romfsb->word0 == ROMSB_WORD0 &&
96        romfsb->word1 == ROMSB_WORD1) {
97        printk(KERN_NOTICE
98               "RAMDISK: romfs filesystem found at block %d\n",
99               start_block);
100        nblocks = (ntohl(romfsb->size)+BLOCK_SIZE-1)>>BLOCK_SIZE_BITS;
101        goto done;
102    }
103
104    if (cramfsb->magic == CRAMFS_MAGIC) {
105        printk(KERN_NOTICE
106               "RAMDISK: cramfs filesystem found at block %d\n",
107               start_block);
108        nblocks = (cramfsb->size + BLOCK_SIZE - 1) >> BLOCK_SIZE_BITS;
109        goto done;
110    }
111
112    /* squashfs is at block zero too */
113    if (le32_to_cpu(squashfsb->s_magic) == SQUASHFS_MAGIC) {
114        printk(KERN_NOTICE
115               "RAMDISK: squashfs filesystem found at block %d\n",
116               start_block);
117        nblocks = (le64_to_cpu(squashfsb->bytes_used) + BLOCK_SIZE - 1)
118             >> BLOCK_SIZE_BITS;
119        goto done;
120    }
121
122    /*
123     * Read block 1 to test for minix and ext2 superblock
124     */
125    sys_lseek(fd, (start_block+1) * BLOCK_SIZE, 0);
126    sys_read(fd, buf, size);
127
128    /* Try minix */
129    if (minixsb->s_magic == MINIX_SUPER_MAGIC ||
130        minixsb->s_magic == MINIX_SUPER_MAGIC2) {
131        printk(KERN_NOTICE
132               "RAMDISK: Minix filesystem found at block %d\n",
133               start_block);
134        nblocks = minixsb->s_nzones << minixsb->s_log_zone_size;
135        goto done;
136    }
137
138    /* Try ext2 */
139    if (ext2sb->s_magic == cpu_to_le16(EXT2_SUPER_MAGIC)) {
140        printk(KERN_NOTICE
141               "RAMDISK: ext2 filesystem found at block %d\n",
142               start_block);
143        nblocks = le32_to_cpu(ext2sb->s_blocks_count) <<
144            le32_to_cpu(ext2sb->s_log_block_size);
145        goto done;
146    }
147
148    printk(KERN_NOTICE
149           "RAMDISK: Couldn't find valid RAM disk image starting at %d.\n",
150           start_block);
151
152done:
153    sys_lseek(fd, start_block * BLOCK_SIZE, 0);
154    kfree(buf);
155    return nblocks;
156}
157
158int __init rd_load_image(char *from)
159{
160    int res = 0;
161    int in_fd, out_fd;
162    unsigned long rd_blocks, devblocks;
163    int nblocks, i, disk;
164    char *buf = NULL;
165    unsigned short rotate = 0;
166    decompress_fn decompressor = NULL;
167#if !defined(CONFIG_S390) && !defined(CONFIG_PPC_ISERIES)
168    char rotator[4] = { '|' , '/' , '-' , '\\' };
169#endif
170
171    out_fd = sys_open("/dev/ram", O_RDWR, 0);
172    if (out_fd < 0)
173        goto out;
174
175    in_fd = sys_open(from, O_RDONLY, 0);
176    if (in_fd < 0)
177        goto noclose_input;
178
179    nblocks = identify_ramdisk_image(in_fd, rd_image_start, &decompressor);
180    if (nblocks < 0)
181        goto done;
182
183    if (nblocks == 0) {
184        if (crd_load(in_fd, out_fd, decompressor) == 0)
185            goto successful_load;
186        goto done;
187    }
188
189    /*
190     * NOTE NOTE: nblocks is not actually blocks but
191     * the number of kibibytes of data to load into a ramdisk.
192     * So any ramdisk block size that is a multiple of 1KiB should
193     * work when the appropriate ramdisk_blocksize is specified
194     * on the command line.
195     *
196     * The default ramdisk_blocksize is 1KiB and it is generally
197     * silly to use anything else, so make sure to use 1KiB
198     * blocksize while generating ext2fs ramdisk-images.
199     */
200    if (sys_ioctl(out_fd, BLKGETSIZE, (unsigned long)&rd_blocks) < 0)
201        rd_blocks = 0;
202    else
203        rd_blocks >>= 1;
204
205    if (nblocks > rd_blocks) {
206        printk("RAMDISK: image too big! (%dKiB/%ldKiB)\n",
207               nblocks, rd_blocks);
208        goto done;
209    }
210
211    /*
212     * OK, time to copy in the data
213     */
214    if (sys_ioctl(in_fd, BLKGETSIZE, (unsigned long)&devblocks) < 0)
215        devblocks = 0;
216    else
217        devblocks >>= 1;
218
219    if (strcmp(from, "/initrd.image") == 0)
220        devblocks = nblocks;
221
222    if (devblocks == 0) {
223        printk(KERN_ERR "RAMDISK: could not determine device size\n");
224        goto done;
225    }
226
227    buf = kmalloc(BLOCK_SIZE, GFP_KERNEL);
228    if (!buf) {
229        printk(KERN_ERR "RAMDISK: could not allocate buffer\n");
230        goto done;
231    }
232
233    printk(KERN_NOTICE "RAMDISK: Loading %dKiB [%ld disk%s] into ram disk... ",
234        nblocks, ((nblocks-1)/devblocks)+1, nblocks>devblocks ? "s" : "");
235    for (i = 0, disk = 1; i < nblocks; i++) {
236        if (i && (i % devblocks == 0)) {
237            printk("done disk #%d.\n", disk++);
238            rotate = 0;
239            if (sys_close(in_fd)) {
240                printk("Error closing the disk.\n");
241                goto noclose_input;
242            }
243            change_floppy("disk #%d", disk);
244            in_fd = sys_open(from, O_RDONLY, 0);
245            if (in_fd < 0) {
246                printk("Error opening disk.\n");
247                goto noclose_input;
248            }
249            printk("Loading disk #%d... ", disk);
250        }
251        sys_read(in_fd, buf, BLOCK_SIZE);
252        sys_write(out_fd, buf, BLOCK_SIZE);
253#if !defined(CONFIG_S390) && !defined(CONFIG_PPC_ISERIES)
254        if (!(i % 16)) {
255            printk("%c\b", rotator[rotate & 0x3]);
256            rotate++;
257        }
258#endif
259    }
260    printk("done.\n");
261
262successful_load:
263    res = 1;
264done:
265    sys_close(in_fd);
266noclose_input:
267    sys_close(out_fd);
268out:
269    kfree(buf);
270    sys_unlink("/dev/ram");
271    return res;
272}
273
274int __init rd_load_disk(int n)
275{
276    if (rd_prompt)
277        change_floppy("root floppy disk to be loaded into RAM disk");
278    create_dev("/dev/root", ROOT_DEV);
279    create_dev("/dev/ram", MKDEV(RAMDISK_MAJOR, n));
280    return rd_load_image("/dev/root");
281}
282
283static int exit_code;
284static int decompress_error;
285static int crd_infd, crd_outfd;
286
287static int __init compr_fill(void *buf, unsigned int len)
288{
289    int r = sys_read(crd_infd, buf, len);
290    if (r < 0)
291        printk(KERN_ERR "RAMDISK: error while reading compressed data");
292    else if (r == 0)
293        printk(KERN_ERR "RAMDISK: EOF while reading compressed data");
294    return r;
295}
296
297static int __init compr_flush(void *window, unsigned int outcnt)
298{
299    int written = sys_write(crd_outfd, window, outcnt);
300    if (written != outcnt) {
301        if (decompress_error == 0)
302            printk(KERN_ERR
303                   "RAMDISK: incomplete write (%d != %d)\n",
304                   written, outcnt);
305        decompress_error = 1;
306        return -1;
307    }
308    return outcnt;
309}
310
311static void __init error(char *x)
312{
313    printk(KERN_ERR "%s\n", x);
314    exit_code = 1;
315    decompress_error = 1;
316}
317
318static int __init crd_load(int in_fd, int out_fd, decompress_fn deco)
319{
320    int result;
321    crd_infd = in_fd;
322    crd_outfd = out_fd;
323    result = deco(NULL, 0, compr_fill, compr_flush, NULL, NULL, error);
324    if (decompress_error)
325        result = 1;
326    return result;
327}
328

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