init/do_mounts_rd.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Many of the syscalls used in this file expect some of the arguments
   4  * to be __user pointers not __kernel pointers.  To limit the sparse
   5  * noise, turn off sparse checking for this file.
   6  */
   7 #ifdef __CHECKER__
   8 #undef __CHECKER__
   9 #warning "Sparse checking disabled for this file"
  10 #endif
  11
  12 #include <linux/kernel.h>
  13 #include <linux/fs.h>
  14 #include <linux/minix_fs.h>
  15 #include <linux/ext2_fs.h>
  16 #include <linux/romfs_fs.h>
  17 #include <uapi/linux/cramfs_fs.h>
  18 #include <linux/initrd.h>
  19 #include <linux/string.h>
  20 #include <linux/slab.h>
  21
  22 #include "do_mounts.h"
  23 #include "../fs/squashfs/squashfs_fs.h"
  24
  25 #include <linux/decompress/generic.h>
  26
  27
  28 int __initdata rd_prompt = 1;/* 1 = prompt for RAM disk, 0 = don't prompt */
  29
  30 static int __init prompt_ramdisk(char *str)
  31 {
  32         rd_prompt = simple_strtol(str,NULL,0) & 1;
  33         return 1;
  34 }
  35 __setup("prompt_ramdisk=", prompt_ramdisk);
  36
  37 int __initdata rd_image_start;          /* starting block # of image */
  38
  39 static int __init ramdisk_start_setup(char *str)
  40 {
  41         rd_image_start = simple_strtol(str,NULL,0);
  42         return 1;
  43 }
  44 __setup("ramdisk_start=", ramdisk_start_setup);
  45
  46 static int __init crd_load(int in_fd, int out_fd, decompress_fn deco);
  47
  48 /*
  49  * This routine tries to find a RAM disk image to load, and returns the
  50  * number of blocks to read for a non-compressed image, 0 if the image
  51  * is a compressed image, and -1 if an image with the right magic
  52  * numbers could not be found.
  53  *
  54  * We currently check for the following magic numbers:
  55  *      minix
  56  *      ext2
  57  *      romfs
  58  *      cramfs
  59  *      squashfs
  60  *      gzip
  61  *      bzip2
  62  *      lzma
  63  *      xz
  64  *      lzo
  65  *      lz4
  66  */
  67 static int __init
  68 identify_ramdisk_image(int fd, int start_block, decompress_fn *decompressor)
  69 {
  70         const int size = 512;
  71         struct minix_super_block *minixsb;
  72         struct romfs_super_block *romfsb;
  73         struct cramfs_super *cramfsb;
  74         struct squashfs_super_block *squashfsb;
  75         int nblocks = -1;
  76         unsigned char *buf;
  77         const char *compress_name;
  78         unsigned long n;
  79
  80         buf = kmalloc(size, GFP_KERNEL);
  81         if (!buf)
  82                 return -ENOMEM;
  83
  84         minixsb = (struct minix_super_block *) buf;
  85         romfsb = (struct romfs_super_block *) buf;
  86         cramfsb = (struct cramfs_super *) buf;
  87         squashfsb = (struct squashfs_super_block *) buf;
  88         memset(buf, 0xe5, size);
  89
  90         /*
  91          * Read block 0 to test for compressed kernel
  92          */
  93         sys_lseek(fd, start_block * BLOCK_SIZE, 0);
  94         sys_read(fd, buf, size);
  95
  96         *decompressor = decompress_method(buf, size, &compress_name);
  97         if (compress_name) {
  98                 printk(KERN_NOTICE "RAMDISK: %s image found at block %d\n",
  99                        compress_name, start_block);
 100                 if (!*decompressor)
 101                         printk(KERN_EMERG
 102                                "RAMDISK: %s decompressor not configured!\n",
 103                                compress_name);
 104                 nblocks = 0;
 105                 goto done;
 106         }
 107
 108         /* romfs is at block zero too */
 109         if (romfsb->word0 == ROMSB_WORD0 &&
 110             romfsb->word1 == ROMSB_WORD1) {
 111                 printk(KERN_NOTICE
 112                        "RAMDISK: romfs filesystem found at block %d\n",
 113                        start_block);
 114                 nblocks = (ntohl(romfsb->size)+BLOCK_SIZE-1)>>BLOCK_SIZE_BITS;
 115                 goto done;
 116         }
 117
 118         if (cramfsb->magic == CRAMFS_MAGIC) {
 119                 printk(KERN_NOTICE
 120                        "RAMDISK: cramfs filesystem found at block %d\n",
 121                        start_block);
 122                 nblocks = (cramfsb->size + BLOCK_SIZE - 1) >> BLOCK_SIZE_BITS;
 123                 goto done;
 124         }
 125
 126         /* squashfs is at block zero too */
 127         if (le32_to_cpu(squashfsb->s_magic) == SQUASHFS_MAGIC) {
 128                 printk(KERN_NOTICE
 129                        "RAMDISK: squashfs filesystem found at block %d\n",
 130                        start_block);
 131                 nblocks = (le64_to_cpu(squashfsb->bytes_used) + BLOCK_SIZE - 1)
 132                          >> BLOCK_SIZE_BITS;
 133                 goto done;
 134         }
 135
 136         /*
 137          * Read 512 bytes further to check if cramfs is padded
 138          */
 139         sys_lseek(fd, start_block * BLOCK_SIZE + 0x200, 0);
 140         sys_read(fd, buf, size);
 141
 142         if (cramfsb->magic == CRAMFS_MAGIC) {
 143                 printk(KERN_NOTICE
 144                        "RAMDISK: cramfs filesystem found at block %d\n",
 145                        start_block);
 146                 nblocks = (cramfsb->size + BLOCK_SIZE - 1) >> BLOCK_SIZE_BITS;
 147                 goto done;
 148         }
 149
 150         /*
 151          * Read block 1 to test for minix and ext2 superblock
 152          */
 153         sys_lseek(fd, (start_block+1) * BLOCK_SIZE, 0);
 154         sys_read(fd, buf, size);
 155
 156         /* Try minix */
 157         if (minixsb->s_magic == MINIX_SUPER_MAGIC ||
 158             minixsb->s_magic == MINIX_SUPER_MAGIC2) {
 159                 printk(KERN_NOTICE
 160                        "RAMDISK: Minix filesystem found at block %d\n",
 161                        start_block);
 162                 nblocks = minixsb->s_nzones << minixsb->s_log_zone_size;
 163                 goto done;
 164         }
 165
 166         /* Try ext2 */
 167         n = ext2_image_size(buf);
 168         if (n) {
 169                 printk(KERN_NOTICE
 170                        "RAMDISK: ext2 filesystem found at block %d\n",
 171                        start_block);
 172                 nblocks = n;
 173                 goto done;
 174         }
 175
 176         printk(KERN_NOTICE
 177                "RAMDISK: Couldn't find valid RAM disk image starting at %d.\n",
 178                start_block);
 179
 180 done:
 181         sys_lseek(fd, start_block * BLOCK_SIZE, 0);
 182         kfree(buf);
 183         return nblocks;
 184 }
 185
 186 int __init rd_load_image(char *from)
 187 {
 188         int res = 0;
 189         int in_fd, out_fd;
 190         unsigned long rd_blocks, devblocks;
 191         int nblocks, i, disk;
 192         char *buf = NULL;
 193         unsigned short rotate = 0;
 194         decompress_fn decompressor = NULL;
 195 #if !defined(CONFIG_S390)
 196         char rotator[4] = { '|' , '/' , '-' , '\\' };
 197 #endif
 198
 199         out_fd = sys_open("/dev/ram", O_RDWR, 0);
 200         if (out_fd < 0)
 201                 goto out;
 202
 203         in_fd = sys_open(from, O_RDONLY, 0);
 204         if (in_fd < 0)
 205                 goto noclose_input;
 206
 207         nblocks = identify_ramdisk_image(in_fd, rd_image_start, &decompressor);
 208         if (nblocks < 0)
 209                 goto done;
 210
 211         if (nblocks == 0) {
 212                 if (crd_load(in_fd, out_fd, 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         if (sys_ioctl(out_fd, BLKGETSIZE, (unsigned long)&rd_blocks) < 0)
 222                 rd_blocks = 0;
 223         else
 224                 rd_blocks >>= 1;
 225
 226         if (nblocks > rd_blocks) {
 227                 printk("RAMDISK: image too big! (%dKiB/%ldKiB)\n",
 228                        nblocks, rd_blocks);
 229                 goto done;
 230         }
 231
 232         /*
 233          * OK, time to copy in the data
 234          */
 235         if (sys_ioctl(in_fd, BLKGETSIZE, (unsigned long)&devblocks) < 0)
 236                 devblocks = 0;
 237         else
 238                 devblocks >>= 1;
 239
 240         if (strcmp(from, "/initrd.image") == 0)
 241                 devblocks = nblocks;
 242
 243         if (devblocks == 0) {
 244                 printk(KERN_ERR "RAMDISK: could not determine device size\n");
 245                 goto done;
 246         }
 247
 248         buf = kmalloc(BLOCK_SIZE, GFP_KERNEL);
 249         if (!buf) {
 250                 printk(KERN_ERR "RAMDISK: could not allocate buffer\n");
 251                 goto done;
 252         }
 253
 254         printk(KERN_NOTICE "RAMDISK: Loading %dKiB [%ld disk%s] into ram disk... ",
 255                 nblocks, ((nblocks-1)/devblocks)+1, nblocks>devblocks ? "s" : "");
 256         for (i = 0, disk = 1; i < nblocks; i++) {
 257                 if (i && (i % devblocks == 0)) {
 258                         printk("done disk #%d.\n", disk++);
 259                         rotate = 0;
 260                         if (sys_close(in_fd)) {
 261                                 printk("Error closing the disk.\n");
 262                                 goto noclose_input;
 263                         }
 264                         change_floppy("disk #%d", disk);
 265                         in_fd = sys_open(from, O_RDONLY, 0);
 266                         if (in_fd < 0)  {
 267                                 printk("Error opening disk.\n");
 268                                 goto noclose_input;
 269                         }
 270                         printk("Loading disk #%d... ", disk);
 271                 }
 272                 sys_read(in_fd, buf, BLOCK_SIZE);
 273                 sys_write(out_fd, buf, BLOCK_SIZE);
 274 #if !defined(CONFIG_S390)
 275                 if (!(i % 16)) {
 276                         pr_cont("%c\b", rotator[rotate & 0x3]);
 277                         rotate++;
 278                 }
 279 #endif
 280         }
 281         printk("done.\n");
 282
 283 successful_load:
 284         res = 1;
 285 done:
 286         sys_close(in_fd);
 287 noclose_input:
 288         sys_close(out_fd);
 289 out:
 290         kfree(buf);
 291         sys_unlink("/dev/ram");
 292         return res;
 293 }
 294
 295 int __init rd_load_disk(int n)
 296 {
 297         if (rd_prompt)
 298                 change_floppy("root floppy disk to be loaded into RAM disk");
 299         create_dev("/dev/root", ROOT_DEV);
 300         create_dev("/dev/ram", MKDEV(RAMDISK_MAJOR, n));
 301         return rd_load_image("/dev/root");
 302 }
 303
 304 static int exit_code;
 305 static int decompress_error;
 306 static int crd_infd, crd_outfd;
 307
 308 static long __init compr_fill(void *buf, unsigned long len)
 309 {
 310         long r = sys_read(crd_infd, buf, len);
 311         if (r < 0)
 312                 printk(KERN_ERR "RAMDISK: error while reading compressed data");
 313         else if (r == 0)
 314                 printk(KERN_ERR "RAMDISK: EOF while reading compressed data");
 315         return r;
 316 }
 317
 318 static long __init compr_flush(void *window, unsigned long outcnt)
 319 {
 320         long written = sys_write(crd_outfd, window, outcnt);
 321         if (written != outcnt) {
 322                 if (decompress_error == 0)
 323                         printk(KERN_ERR
 324                                "RAMDISK: incomplete write (%ld != %ld)\n",
 325                                written, outcnt);
 326                 decompress_error = 1;
 327                 return -1;
 328         }
 329         return outcnt;
 330 }
 331
 332 static void __init error(char *x)
 333 {
 334         printk(KERN_ERR "%s\n", x);
 335         exit_code = 1;
 336         decompress_error = 1;
 337 }
 338
 339 static int __init crd_load(int in_fd, int out_fd, decompress_fn deco)
 340 {
 341         int result;
 342         crd_infd = in_fd;
 343         crd_outfd = out_fd;
 344
 345         if (!deco) {
 346                 pr_emerg("Invalid ramdisk decompression routine.  "
 347                          "Select appropriate config option.\n");
 348                 panic("Could not decompress initial ramdisk image.");
 349         }
 350
 351         result = deco(NULL, 0, compr_fill, compr_flush, NULL, NULL, error);
 352         if (decompress_error)
 353                 result = 1;
 354         return result;
 355 }