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
11#include "do_mounts.h"
12#include "../fs/squashfs/squashfs_fs.h"
13
14#include <linux/decompress/generic.h>
15
16
17int __initdata rd_prompt = 1;/* 1 = prompt for RAM disk, 0 = don't prompt */
18
19static int __init prompt_ramdisk(char *str)
20{
21    rd_prompt = simple_strtol(str,NULL,0) & 1;
22    return 1;
23}
24__setup("prompt_ramdisk=", prompt_ramdisk);
25
26int __initdata rd_image_start; /* starting block # of image */
27
28static int __init ramdisk_start_setup(char *str)
29{
30    rd_image_start = simple_strtol(str,NULL,0);
31    return 1;
32}
33__setup("ramdisk_start=", ramdisk_start_setup);
34
35static int __init crd_load(int in_fd, int out_fd, decompress_fn deco);
36
37/*
38 * This routine tries to find a RAM disk image to load, and returns the
39 * number of blocks to read for a non-compressed image, 0 if the image
40 * is a compressed image, and -1 if an image with the right magic
41 * numbers could not be found.
42 *
43 * We currently check for the following magic numbers:
44 * minix
45 * ext2
46 * romfs
47 * cramfs
48 * squashfs
49 * gzip
50 */
51static int __init
52identify_ramdisk_image(int fd, int start_block, decompress_fn *decompressor)
53{
54    const int size = 512;
55    struct minix_super_block *minixsb;
56    struct ext2_super_block *ext2sb;
57    struct romfs_super_block *romfsb;
58    struct cramfs_super *cramfsb;
59    struct squashfs_super_block *squashfsb;
60    int nblocks = -1;
61    unsigned char *buf;
62    const char *compress_name;
63
64    buf = kmalloc(size, GFP_KERNEL);
65    if (!buf)
66        return -1;
67
68    minixsb = (struct minix_super_block *) buf;
69    ext2sb = (struct ext2_super_block *) buf;
70    romfsb = (struct romfs_super_block *) buf;
71    cramfsb = (struct cramfs_super *) buf;
72    squashfsb = (struct squashfs_super_block *) buf;
73    memset(buf, 0xe5, size);
74
75    /*
76     * Read block 0 to test for compressed kernel
77     */
78    sys_lseek(fd, start_block * BLOCK_SIZE, 0);
79    sys_read(fd, buf, size);
80
81    *decompressor = decompress_method(buf, size, &compress_name);
82    if (compress_name) {
83        printk(KERN_NOTICE "RAMDISK: %s image found at block %d\n",
84               compress_name, start_block);
85        if (!*decompressor)
86            printk(KERN_EMERG
87                   "RAMDISK: %s decompressor not configured!\n",
88                   compress_name);
89        nblocks = 0;
90        goto done;
91    }
92
93    /* romfs is at block zero too */
94    if (romfsb->word0 == ROMSB_WORD0 &&
95        romfsb->word1 == ROMSB_WORD1) {
96        printk(KERN_NOTICE
97               "RAMDISK: romfs filesystem found at block %d\n",
98               start_block);
99        nblocks = (ntohl(romfsb->size)+BLOCK_SIZE-1)>>BLOCK_SIZE_BITS;
100        goto done;
101    }
102
103    if (cramfsb->magic == CRAMFS_MAGIC) {
104        printk(KERN_NOTICE
105               "RAMDISK: cramfs filesystem found at block %d\n",
106               start_block);
107        nblocks = (cramfsb->size + BLOCK_SIZE - 1) >> BLOCK_SIZE_BITS;
108        goto done;
109    }
110
111    /* squashfs is at block zero too */
112    if (le32_to_cpu(squashfsb->s_magic) == SQUASHFS_MAGIC) {
113        printk(KERN_NOTICE
114               "RAMDISK: squashfs filesystem found at block %d\n",
115               start_block);
116        nblocks = (le64_to_cpu(squashfsb->bytes_used) + BLOCK_SIZE - 1)
117             >> BLOCK_SIZE_BITS;
118        goto done;
119    }
120
121    /*
122     * Read block 1 to test for minix and ext2 superblock
123     */
124    sys_lseek(fd, (start_block+1) * BLOCK_SIZE, 0);
125    sys_read(fd, buf, size);
126
127    /* Try minix */
128    if (minixsb->s_magic == MINIX_SUPER_MAGIC ||
129        minixsb->s_magic == MINIX_SUPER_MAGIC2) {
130        printk(KERN_NOTICE
131               "RAMDISK: Minix filesystem found at block %d\n",
132               start_block);
133        nblocks = minixsb->s_nzones << minixsb->s_log_zone_size;
134        goto done;
135    }
136
137    /* Try ext2 */
138    if (ext2sb->s_magic == cpu_to_le16(EXT2_SUPER_MAGIC)) {
139        printk(KERN_NOTICE
140               "RAMDISK: ext2 filesystem found at block %d\n",
141               start_block);
142        nblocks = le32_to_cpu(ext2sb->s_blocks_count) <<
143            le32_to_cpu(ext2sb->s_log_block_size);
144        goto done;
145    }
146
147    printk(KERN_NOTICE
148           "RAMDISK: Couldn't find valid RAM disk image starting at %d.\n",
149           start_block);
150
151done:
152    sys_lseek(fd, start_block * BLOCK_SIZE, 0);
153    kfree(buf);
154    return nblocks;
155}
156
157int __init rd_load_image(char *from)
158{
159    int res = 0;
160    int in_fd, out_fd;
161    unsigned long rd_blocks, devblocks;
162    int nblocks, i, disk;
163    char *buf = NULL;
164    unsigned short rotate = 0;
165    decompress_fn decompressor = NULL;
166#if !defined(CONFIG_S390) && !defined(CONFIG_PPC_ISERIES)
167    char rotator[4] = { '|' , '/' , '-' , '\\' };
168#endif
169
170    out_fd = sys_open("/dev/ram", O_RDWR, 0);
171    if (out_fd < 0)
172        goto out;
173
174    in_fd = sys_open(from, O_RDONLY, 0);
175    if (in_fd < 0)
176        goto noclose_input;
177
178    nblocks = identify_ramdisk_image(in_fd, rd_image_start, &decompressor);
179    if (nblocks < 0)
180        goto done;
181
182    if (nblocks == 0) {
183        if (crd_load(in_fd, out_fd, decompressor) == 0)
184            goto successful_load;
185        goto done;
186    }
187
188    /*
189     * NOTE NOTE: nblocks is not actually blocks but
190     * the number of kibibytes of data to load into a ramdisk.
191     * So any ramdisk block size that is a multiple of 1KiB should
192     * work when the appropriate ramdisk_blocksize is specified
193     * on the command line.
194     *
195     * The default ramdisk_blocksize is 1KiB and it is generally
196     * silly to use anything else, so make sure to use 1KiB
197     * blocksize while generating ext2fs ramdisk-images.
198     */
199    if (sys_ioctl(out_fd, BLKGETSIZE, (unsigned long)&rd_blocks) < 0)
200        rd_blocks = 0;
201    else
202        rd_blocks >>= 1;
203
204    if (nblocks > rd_blocks) {
205        printk("RAMDISK: image too big! (%dKiB/%ldKiB)\n",
206               nblocks, rd_blocks);
207        goto done;
208    }
209
210    /*
211     * OK, time to copy in the data
212     */
213    if (sys_ioctl(in_fd, BLKGETSIZE, (unsigned long)&devblocks) < 0)
214        devblocks = 0;
215    else
216        devblocks >>= 1;
217
218    if (strcmp(from, "/initrd.image") == 0)
219        devblocks = nblocks;
220
221    if (devblocks == 0) {
222        printk(KERN_ERR "RAMDISK: could not determine device size\n");
223        goto done;
224    }
225
226    buf = kmalloc(BLOCK_SIZE, GFP_KERNEL);
227    if (!buf) {
228        printk(KERN_ERR "RAMDISK: could not allocate buffer\n");
229        goto done;
230    }
231
232    printk(KERN_NOTICE "RAMDISK: Loading %dKiB [%ld disk%s] into ram disk... ",
233        nblocks, ((nblocks-1)/devblocks)+1, nblocks>devblocks ? "s" : "");
234    for (i = 0, disk = 1; i < nblocks; i++) {
235        if (i && (i % devblocks == 0)) {
236            printk("done disk #%d.\n", disk++);
237            rotate = 0;
238            if (sys_close(in_fd)) {
239                printk("Error closing the disk.\n");
240                goto noclose_input;
241            }
242            change_floppy("disk #%d", disk);
243            in_fd = sys_open(from, O_RDONLY, 0);
244            if (in_fd < 0) {
245                printk("Error opening disk.\n");
246                goto noclose_input;
247            }
248            printk("Loading disk #%d... ", disk);
249        }
250        sys_read(in_fd, buf, BLOCK_SIZE);
251        sys_write(out_fd, buf, BLOCK_SIZE);
252#if !defined(CONFIG_S390) && !defined(CONFIG_PPC_ISERIES)
253        if (!(i % 16)) {
254            printk("%c\b", rotator[rotate & 0x3]);
255            rotate++;
256        }
257#endif
258    }
259    printk("done.\n");
260
261successful_load:
262    res = 1;
263done:
264    sys_close(in_fd);
265noclose_input:
266    sys_close(out_fd);
267out:
268    kfree(buf);
269    sys_unlink("/dev/ram");
270    return res;
271}
272
273int __init rd_load_disk(int n)
274{
275    if (rd_prompt)
276        change_floppy("root floppy disk to be loaded into RAM disk");
277    create_dev("/dev/root", ROOT_DEV);
278    create_dev("/dev/ram", MKDEV(RAMDISK_MAJOR, n));
279    return rd_load_image("/dev/root");
280}
281
282static int exit_code;
283static int decompress_error;
284static int crd_infd, crd_outfd;
285
286static int __init compr_fill(void *buf, unsigned int len)
287{
288    int r = sys_read(crd_infd, buf, len);
289    if (r < 0)
290        printk(KERN_ERR "RAMDISK: error while reading compressed data");
291    else if (r == 0)
292        printk(KERN_ERR "RAMDISK: EOF while reading compressed data");
293    return r;
294}
295
296static int __init compr_flush(void *window, unsigned int outcnt)
297{
298    int written = sys_write(crd_outfd, window, outcnt);
299    if (written != outcnt) {
300        if (decompress_error == 0)
301            printk(KERN_ERR
302                   "RAMDISK: incomplete write (%d != %d)\n",
303                   written, outcnt);
304        decompress_error = 1;
305        return -1;
306    }
307    return outcnt;
308}
309
310static void __init error(char *x)
311{
312    printk(KERN_ERR "%s\n", x);
313    exit_code = 1;
314    decompress_error = 1;
315}
316
317static int __init crd_load(int in_fd, int out_fd, decompress_fn deco)
318{
319    int result;
320    crd_infd = in_fd;
321    crd_outfd = out_fd;
322    result = deco(NULL, 0, compr_fill, compr_flush, NULL, NULL, error);
323    if (decompress_error)
324        result = 1;
325    return result;
326}
327

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