init/do_mounts_rd.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  * Many of the syscalls used in this file expect some of the arguments
  * to be __user pointers not __kernel pointers.  To limit the sparse
  * noise, turn off sparse checking for this file.
  */
 #ifdef __CHECKER__
 #undef __CHECKER__
 #warning "Sparse checking disabled for this file"
 #endif

 #include <linux/kernel.h>
 #include <linux/fs.h>
 #include <linux/minix_fs.h>
 #include <linux/ext2_fs.h>
 #include <linux/romfs_fs.h>
 #include <uapi/linux/cramfs_fs.h>
 #include <linux/initrd.h>
 #include <linux/string.h>
 #include <linux/slab.h>

 #include "do_mounts.h"
 #include "../fs/squashfs/squashfs_fs.h"

 #include <linux/decompress/generic.h>


 int __initdata rd_prompt = 1;/* 1 = prompt for RAM disk, 0 = don't prompt */

 static int __init prompt_ramdisk(char *str)
 {
 	rd_prompt = simple_strtol(str,NULL,0) & 1;
 	return 1;
 }
 __setup("prompt_ramdisk=", prompt_ramdisk);

 int __initdata rd_image_start;		/* starting block # of image */

 static int __init ramdisk_start_setup(char *str)
 {
 	rd_image_start = simple_strtol(str,NULL,0);
 	return 1;
 }
 __setup("ramdisk_start=", ramdisk_start_setup);

 static int __init crd_load(int in_fd, int out_fd, decompress_fn deco);

 /*
  * This routine tries to find a RAM disk image to load, and returns the
  * number of blocks to read for a non-compressed image, 0 if the image
  * is a compressed image, and -1 if an image with the right magic
  * numbers could not be found.
  *
  * We currently check for the following magic numbers:
  *	minix
  *	ext2
  *	romfs
  *	cramfs
  *	squashfs
  *	gzip
  *	bzip2
  *	lzma
  *	xz
  *	lzo
  *	lz4
  */
 static int __init
 identify_ramdisk_image(int fd, int start_block, decompress_fn *decompressor)
 {
 	const int size = 512;
 	struct minix_super_block *minixsb;
 	struct romfs_super_block *romfsb;
 	struct cramfs_super *cramfsb;
 	struct squashfs_super_block *squashfsb;
 	int nblocks = -1;
 	unsigned char *buf;
 	const char *compress_name;
 	unsigned long n;

 	buf = kmalloc(size, GFP_KERNEL);
 	if (!buf)
 		return -ENOMEM;

 	minixsb = (struct minix_super_block *) buf;
 	romfsb = (struct romfs_super_block *) buf;
 	cramfsb = (struct cramfs_super *) buf;
 	squashfsb = (struct squashfs_super_block *) buf;
 	memset(buf, 0xe5, size);

 	/*
 	 * Read block 0 to test for compressed kernel
 	 */
 	ksys_lseek(fd, start_block * BLOCK_SIZE, 0);
 	ksys_read(fd, buf, size);

 	*decompressor = decompress_method(buf, size, &compress_name);
 	if (compress_name) {
 		printk(KERN_NOTICE "RAMDISK: %s image found at block %d\n",
 		       compress_name, start_block);
 		if (!*decompressor)
 			printk(KERN_EMERG
 			       "RAMDISK: %s decompressor not configured!\n",
 			       compress_name);
 		nblocks = 0;
 		goto done;
 	}

 	/* romfs is at block zero too */
 	if (romfsb->word0 == ROMSB_WORD0 &&
 	    romfsb->word1 == ROMSB_WORD1) {
 		printk(KERN_NOTICE
 		       "RAMDISK: romfs filesystem found at block %d\n",
 		       start_block);
 		nblocks = (ntohl(romfsb->size)+BLOCK_SIZE-1)>>BLOCK_SIZE_BITS;
 		goto done;
 	}

 	if (cramfsb->magic == CRAMFS_MAGIC) {
 		printk(KERN_NOTICE
 		       "RAMDISK: cramfs filesystem found at block %d\n",
 		       start_block);
 		nblocks = (cramfsb->size + BLOCK_SIZE - 1) >> BLOCK_SIZE_BITS;
 		goto done;
 	}

 	/* squashfs is at block zero too */
 	if (le32_to_cpu(squashfsb->s_magic) == SQUASHFS_MAGIC) {
 		printk(KERN_NOTICE
 		       "RAMDISK: squashfs filesystem found at block %d\n",
 		       start_block);
 		nblocks = (le64_to_cpu(squashfsb->bytes_used) + BLOCK_SIZE - 1)
 			 >> BLOCK_SIZE_BITS;
 		goto done;
 	}

 	/*
 	 * Read 512 bytes further to check if cramfs is padded
 	 */
 	ksys_lseek(fd, start_block * BLOCK_SIZE + 0x200, 0);
 	ksys_read(fd, buf, size);

 	if (cramfsb->magic == CRAMFS_MAGIC) {
 		printk(KERN_NOTICE
 		       "RAMDISK: cramfs filesystem found at block %d\n",
 		       start_block);
 		nblocks = (cramfsb->size + BLOCK_SIZE - 1) >> BLOCK_SIZE_BITS;
 		goto done;
 	}

 	/*
 	 * Read block 1 to test for minix and ext2 superblock
 	 */
 	ksys_lseek(fd, (start_block+1) * BLOCK_SIZE, 0);
 	ksys_read(fd, buf, size);

 	/* Try minix */
 	if (minixsb->s_magic == MINIX_SUPER_MAGIC ||
 	    minixsb->s_magic == MINIX_SUPER_MAGIC2) {
 		printk(KERN_NOTICE
 		       "RAMDISK: Minix filesystem found at block %d\n",
 		       start_block);
 		nblocks = minixsb->s_nzones << minixsb->s_log_zone_size;
 		goto done;
 	}

 	/* Try ext2 */
 	n = ext2_image_size(buf);
 	if (n) {
 		printk(KERN_NOTICE
 		       "RAMDISK: ext2 filesystem found at block %d\n",
 		       start_block);
 		nblocks = n;
 		goto done;
 	}

 	printk(KERN_NOTICE
 	       "RAMDISK: Couldn't find valid RAM disk image starting at %d.\n",
 	       start_block);

 done:
 	ksys_lseek(fd, start_block * BLOCK_SIZE, 0);
 	kfree(buf);
 	return nblocks;
 }

 int __init rd_load_image(char *from)
 {
 	int res = 0;
 	int in_fd, out_fd;
 	unsigned long rd_blocks, devblocks;
 	int nblocks, i, disk;
 	char *buf = NULL;
 	unsigned short rotate = 0;
 	decompress_fn decompressor = NULL;
 #if !defined(CONFIG_S390)
 	char rotator[4] = { '|' , '/' , '-' , '\\' };
 #endif

 	out_fd = ksys_open("/dev/ram", O_RDWR, 0);
 	if (out_fd < 0)
 		goto out;

 	in_fd = ksys_open(from, O_RDONLY, 0);
 	if (in_fd < 0)
 		goto noclose_input;

 	nblocks = identify_ramdisk_image(in_fd, rd_image_start, &decompressor);
 	if (nblocks < 0)
 		goto done;

 	if (nblocks == 0) {
 		if (crd_load(in_fd, out_fd, decompressor) == 0)
 			goto successful_load;
 		goto done;
 	}

 	/*
 	 * NOTE NOTE: nblocks is not actually blocks but
 	 * the number of kibibytes of data to load into a ramdisk.
 	 */
 	if (ksys_ioctl(out_fd, BLKGETSIZE, (unsigned long)&rd_blocks) < 0)
 		rd_blocks = 0;
 	else
 		rd_blocks >>= 1;

 	if (nblocks > rd_blocks) {
 		printk("RAMDISK: image too big! (%dKiB/%ldKiB)\n",
 		       nblocks, rd_blocks);
 		goto done;
 	}

 	/*
 	 * OK, time to copy in the data
 	 */
 	if (ksys_ioctl(in_fd, BLKGETSIZE, (unsigned long)&devblocks) < 0)
 		devblocks = 0;
 	else
 		devblocks >>= 1;

 	if (strcmp(from, "/initrd.image") == 0)
 		devblocks = nblocks;

 	if (devblocks == 0) {
 		printk(KERN_ERR "RAMDISK: could not determine device size\n");
 		goto done;
 	}

 	buf = kmalloc(BLOCK_SIZE, GFP_KERNEL);
 	if (!buf) {
 		printk(KERN_ERR "RAMDISK: could not allocate buffer\n");
 		goto done;
 	}

 	printk(KERN_NOTICE "RAMDISK: Loading %dKiB [%ld disk%s] into ram disk... ",
 		nblocks, ((nblocks-1)/devblocks)+1, nblocks>devblocks ? "s" : "");
 	for (i = 0, disk = 1; i < nblocks; i++) {
 		if (i && (i % devblocks == 0)) {
 			printk("done disk #%d.\n", disk++);
 			rotate = 0;
 			if (ksys_close(in_fd)) {
 				printk("Error closing the disk.\n");
 				goto noclose_input;
 			}
 			change_floppy("disk #%d", disk);
 			in_fd = ksys_open(from, O_RDONLY, 0);
 			if (in_fd < 0)  {
 				printk("Error opening disk.\n");
 				goto noclose_input;
 			}
 			printk("Loading disk #%d... ", disk);
 		}
 		ksys_read(in_fd, buf, BLOCK_SIZE);
 		ksys_write(out_fd, buf, BLOCK_SIZE);
 #if !defined(CONFIG_S390)
 		if (!(i % 16)) {
 			pr_cont("%c\b", rotator[rotate & 0x3]);
 			rotate++;
 		}
 #endif
 	}
 	printk("done.\n");

 successful_load:
 	res = 1;
 done:
 	ksys_close(in_fd);
 noclose_input:
 	ksys_close(out_fd);
 out:
 	kfree(buf);
 	ksys_unlink("/dev/ram");
 	return res;
 }

 int __init rd_load_disk(int n)
 {
 	if (rd_prompt)
 		change_floppy("root floppy disk to be loaded into RAM disk");
 	create_dev("/dev/root", ROOT_DEV);
 	create_dev("/dev/ram", MKDEV(RAMDISK_MAJOR, n));
 	return rd_load_image("/dev/root");
 }

 static int exit_code;
 static int decompress_error;
 static int crd_infd, crd_outfd;

 static long __init compr_fill(void *buf, unsigned long len)
 {
 	long r = ksys_read(crd_infd, buf, len);
 	if (r < 0)
 		printk(KERN_ERR "RAMDISK: error while reading compressed data");
 	else if (r == 0)
 		printk(KERN_ERR "RAMDISK: EOF while reading compressed data");
 	return r;
 }

 static long __init compr_flush(void *window, unsigned long outcnt)
 {
 	long written = ksys_write(crd_outfd, window, outcnt);
 	if (written != outcnt) {
 		if (decompress_error == 0)
 			printk(KERN_ERR
 			       "RAMDISK: incomplete write (%ld != %ld)\n",
 			       written, outcnt);
 		decompress_error = 1;
 		return -1;
 	}
 	return outcnt;
 }

 static void __init error(char *x)
 {
 	printk(KERN_ERR "%s\n", x);
 	exit_code = 1;
 	decompress_error = 1;
 }

 static int __init crd_load(int in_fd, int out_fd, decompress_fn deco)
 {
 	int result;
 	crd_infd = in_fd;
 	crd_outfd = out_fd;

 	if (!deco) {
 		pr_emerg("Invalid ramdisk decompression routine.  "
 			 "Select appropriate config option.\n");
 		panic("Could not decompress initial ramdisk image.");
 	}

 	result = deco(NULL, 0, compr_fill, compr_flush, NULL, NULL, error);
 	if (decompress_error)
 		result = 1;
 	return result;
 }
	// SPDX-License-Identifier: GPL-2.0
	/*
	* Many of the syscalls used in this file expect some of the arguments
	* to be __user pointers not __kernel pointers. To limit the sparse
	* noise, turn off sparse checking for this file.
	*/
	#ifdef __CHECKER__
	#undef __CHECKER__
	#warning "Sparse checking disabled for this file"
	#endif

	#include <linux/kernel.h>
	#include <linux/fs.h>
	#include <linux/minix_fs.h>
	#include <linux/ext2_fs.h>
	#include <linux/romfs_fs.h>
	#include <uapi/linux/cramfs_fs.h>
	#include <linux/initrd.h>
	#include <linux/string.h>
	#include <linux/slab.h>

	#include "do_mounts.h"
	#include "../fs/squashfs/squashfs_fs.h"

	#include <linux/decompress/generic.h>


	int __initdata rd_prompt = 1;/* 1 = prompt for RAM disk, 0 = don't prompt */

	static int __init prompt_ramdisk(char *str)
	{
	rd_prompt = simple_strtol(str,NULL,0) & 1;
	return 1;
	}
	__setup("prompt_ramdisk=", prompt_ramdisk);

	int __initdata rd_image_start; /* starting block # of image */

	static int __init ramdisk_start_setup(char *str)
	{
	rd_image_start = simple_strtol(str,NULL,0);
	return 1;
	}
	__setup("ramdisk_start=", ramdisk_start_setup);

	static int __init crd_load(int in_fd, int out_fd, decompress_fn deco);

	/*
	* This routine tries to find a RAM disk image to load, and returns the
	* number of blocks to read for a non-compressed image, 0 if the image
	* is a compressed image, and -1 if an image with the right magic
	* numbers could not be found.
	*
	* We currently check for the following magic numbers:
	* minix
	* ext2
	* romfs
	* cramfs
	* squashfs
	* gzip
	* bzip2
	* lzma
	* xz
	* lzo
	* lz4
	*/
	static int __init
	identify_ramdisk_image(int fd, int start_block, decompress_fn *decompressor)
	{
	const int size = 512;
	struct minix_super_block *minixsb;
	struct romfs_super_block *romfsb;
	struct cramfs_super *cramfsb;
	struct squashfs_super_block *squashfsb;
	int nblocks = -1;
	unsigned char *buf;
	const char *compress_name;
	unsigned long n;

	buf = kmalloc(size, GFP_KERNEL);
	if (!buf)
	return -ENOMEM;

	minixsb = (struct minix_super_block *) buf;
	romfsb = (struct romfs_super_block *) buf;
	cramfsb = (struct cramfs_super *) buf;
	squashfsb = (struct squashfs_super_block *) buf;
	memset(buf, 0xe5, size);

	/*
	* Read block 0 to test for compressed kernel
	*/
	ksys_lseek(fd, start_block * BLOCK_SIZE, 0);
	ksys_read(fd, buf, size);

	*decompressor = decompress_method(buf, size, &compress_name);
	if (compress_name) {
	printk(KERN_NOTICE "RAMDISK: %s image found at block %d\n",
	compress_name, start_block);
	if (!*decompressor)
	printk(KERN_EMERG
	"RAMDISK: %s decompressor not configured!\n",
	compress_name);
	nblocks = 0;
	goto done;
	}

	/* romfs is at block zero too */
	if (romfsb->word0 == ROMSB_WORD0 &&
	romfsb->word1 == ROMSB_WORD1) {
	printk(KERN_NOTICE
	"RAMDISK: romfs filesystem found at block %d\n",
	start_block);
	nblocks = (ntohl(romfsb->size)+BLOCK_SIZE-1)>>BLOCK_SIZE_BITS;
	goto done;
	}

	if (cramfsb->magic == CRAMFS_MAGIC) {
	printk(KERN_NOTICE
	"RAMDISK: cramfs filesystem found at block %d\n",
	start_block);
	nblocks = (cramfsb->size + BLOCK_SIZE - 1) >> BLOCK_SIZE_BITS;
	goto done;
	}

	/* squashfs is at block zero too */
	if (le32_to_cpu(squashfsb->s_magic) == SQUASHFS_MAGIC) {
	printk(KERN_NOTICE
	"RAMDISK: squashfs filesystem found at block %d\n",
	start_block);
	nblocks = (le64_to_cpu(squashfsb->bytes_used) + BLOCK_SIZE - 1)
	>> BLOCK_SIZE_BITS;
	goto done;
	}

	/*
	* Read 512 bytes further to check if cramfs is padded
	*/
	ksys_lseek(fd, start_block * BLOCK_SIZE + 0x200, 0);
	ksys_read(fd, buf, size);

	if (cramfsb->magic == CRAMFS_MAGIC) {
	printk(KERN_NOTICE
	"RAMDISK: cramfs filesystem found at block %d\n",
	start_block);
	nblocks = (cramfsb->size + BLOCK_SIZE - 1) >> BLOCK_SIZE_BITS;
	goto done;
	}

	/*
	* Read block 1 to test for minix and ext2 superblock
	*/
	ksys_lseek(fd, (start_block+1) * BLOCK_SIZE, 0);
	ksys_read(fd, buf, size);

	/* Try minix */
	if (minixsb->s_magic == MINIX_SUPER_MAGIC \|\|
	minixsb->s_magic == MINIX_SUPER_MAGIC2) {
	printk(KERN_NOTICE
	"RAMDISK: Minix filesystem found at block %d\n",
	start_block);
	nblocks = minixsb->s_nzones << minixsb->s_log_zone_size;
	goto done;
	}

	/* Try ext2 */
	n = ext2_image_size(buf);
	if (n) {
	printk(KERN_NOTICE
	"RAMDISK: ext2 filesystem found at block %d\n",
	start_block);
	nblocks = n;
	goto done;
	}

	printk(KERN_NOTICE
	"RAMDISK: Couldn't find valid RAM disk image starting at %d.\n",
	start_block);

	done:
	ksys_lseek(fd, start_block * BLOCK_SIZE, 0);
	kfree(buf);
	return nblocks;
	}

	int __init rd_load_image(char *from)
	{
	int res = 0;
	int in_fd, out_fd;
	unsigned long rd_blocks, devblocks;
	int nblocks, i, disk;
	char *buf = NULL;
	unsigned short rotate = 0;
	decompress_fn decompressor = NULL;
	#if !defined(CONFIG_S390)
	char rotator[4] = { '\|' , '/' , '-' , '\\' };
	#endif

	out_fd = ksys_open("/dev/ram", O_RDWR, 0);
	if (out_fd < 0)
	goto out;

	in_fd = ksys_open(from, O_RDONLY, 0);
	if (in_fd < 0)
	goto noclose_input;

	nblocks = identify_ramdisk_image(in_fd, rd_image_start, &decompressor);
	if (nblocks < 0)
	goto done;

	if (nblocks == 0) {
	if (crd_load(in_fd, out_fd, decompressor) == 0)
	goto successful_load;
	goto done;
	}

	/*
	* NOTE NOTE: nblocks is not actually blocks but
	* the number of kibibytes of data to load into a ramdisk.
	*/
	if (ksys_ioctl(out_fd, BLKGETSIZE, (unsigned long)&rd_blocks) < 0)
	rd_blocks = 0;
	else
	rd_blocks >>= 1;

	if (nblocks > rd_blocks) {
	printk("RAMDISK: image too big! (%dKiB/%ldKiB)\n",
	nblocks, rd_blocks);
	goto done;
	}

	/*
	* OK, time to copy in the data
	*/
	if (ksys_ioctl(in_fd, BLKGETSIZE, (unsigned long)&devblocks) < 0)
	devblocks = 0;
	else
	devblocks >>= 1;

	if (strcmp(from, "/initrd.image") == 0)
	devblocks = nblocks;

	if (devblocks == 0) {
	printk(KERN_ERR "RAMDISK: could not determine device size\n");
	goto done;
	}

	buf = kmalloc(BLOCK_SIZE, GFP_KERNEL);
	if (!buf) {
	printk(KERN_ERR "RAMDISK: could not allocate buffer\n");
	goto done;
	}

	printk(KERN_NOTICE "RAMDISK: Loading %dKiB [%ld disk%s] into ram disk... ",
	nblocks, ((nblocks-1)/devblocks)+1, nblocks>devblocks ? "s" : "");
	for (i = 0, disk = 1; i < nblocks; i++) {
	if (i && (i % devblocks == 0)) {
	printk("done disk #%d.\n", disk++);
	rotate = 0;
	if (ksys_close(in_fd)) {
	printk("Error closing the disk.\n");
	goto noclose_input;
	}
	change_floppy("disk #%d", disk);
	in_fd = ksys_open(from, O_RDONLY, 0);
	if (in_fd < 0) {
	printk("Error opening disk.\n");
	goto noclose_input;
	}
	printk("Loading disk #%d... ", disk);
	}
	ksys_read(in_fd, buf, BLOCK_SIZE);
	ksys_write(out_fd, buf, BLOCK_SIZE);
	#if !defined(CONFIG_S390)
	if (!(i % 16)) {
	pr_cont("%c\b", rotator[rotate & 0x3]);
	rotate++;
	}
	#endif
	}
	printk("done.\n");

	successful_load:
	res = 1;
	done:
	ksys_close(in_fd);
	noclose_input:
	ksys_close(out_fd);
	out:
	kfree(buf);
	ksys_unlink("/dev/ram");
	return res;
	}

	int __init rd_load_disk(int n)
	{
	if (rd_prompt)
	change_floppy("root floppy disk to be loaded into RAM disk");
	create_dev("/dev/root", ROOT_DEV);
	create_dev("/dev/ram", MKDEV(RAMDISK_MAJOR, n));
	return rd_load_image("/dev/root");
	}

	static int exit_code;
	static int decompress_error;
	static int crd_infd, crd_outfd;

	static long __init compr_fill(void *buf, unsigned long len)
	{
	long r = ksys_read(crd_infd, buf, len);
	if (r < 0)
	printk(KERN_ERR "RAMDISK: error while reading compressed data");
	else if (r == 0)
	printk(KERN_ERR "RAMDISK: EOF while reading compressed data");
	return r;
	}

	static long __init compr_flush(void *window, unsigned long outcnt)
	{
	long written = ksys_write(crd_outfd, window, outcnt);
	if (written != outcnt) {
	if (decompress_error == 0)
	printk(KERN_ERR
	"RAMDISK: incomplete write (%ld != %ld)\n",
	written, outcnt);
	decompress_error = 1;
	return -1;
	}
	return outcnt;
	}

	static void __init error(char *x)
	{
	printk(KERN_ERR "%s\n", x);
	exit_code = 1;
	decompress_error = 1;
	}

	static int __init crd_load(int in_fd, int out_fd, decompress_fn deco)
	{
	int result;
	crd_infd = in_fd;
	crd_outfd = out_fd;

	if (!deco) {
	pr_emerg("Invalid ramdisk decompression routine. "
	"Select appropriate config option.\n");
	panic("Could not decompress initial ramdisk image.");
	}

	result = deco(NULL, 0, compr_fill, compr_flush, NULL, NULL, error);
	if (decompress_error)
	result = 1;
	return result;
	}