nuclear@90: /* This code is used by the kernel AND by userspace filesystem-related tools.
nuclear@90:  * The kernel-specific parts are conditionally compiled in #ifdef KERNEL blocks
nuclear@90:  * the rest of the code should be independent.
nuclear@90:  */
nuclear@88: #include <stdio.h>
nuclear@89: #include <stdlib.h>
nuclear@94: #include <string.h>
nuclear@90: #include <errno.h>
nuclear@94: #include <assert.h>
nuclear@88: #include "fs.h"
nuclear@93: #include "bdev.h"
nuclear@90: 
nuclear@89: 
nuclear@93: int openfs(struct filesys *fs, dev_t dev);
nuclear@94: static int read_superblock(struct filesys *fs);
nuclear@94: static int write_superblock(struct filesys *fs);
nuclear@94: static int get_inode(struct filesys *fs, int ino, struct inode *inode);
nuclear@94: static int put_inode(struct filesys *fs, struct inode *inode);
nuclear@90: 
nuclear@93: int openfs(struct filesys *fs, dev_t dev)
nuclear@93: {
nuclear@93: 	int res;
nuclear@93: 	struct block_device *bdev;
nuclear@94: 
nuclear@94: 	assert(BLKSZ % sizeof(struct inode) == 0);
nuclear@89: 
nuclear@93: 	if(!(bdev = blk_open(dev))) {
nuclear@93: 		return -ENOENT;
nuclear@90: 	}
nuclear@94: 	fs->bdev = bdev;
nuclear@90: 
nuclear@93: 	/* read the superblock */
nuclear@94: 	if(!(fs->sb = malloc(BLKSZ))) {
nuclear@93: 		res = -ENOMEM;
nuclear@93: 		goto done;
nuclear@93: 	}
nuclear@94: 	if((res = read_superblock(fs)) != 0) {
nuclear@93: 		goto done;
nuclear@93: 	}
nuclear@90: 
nuclear@93: 
nuclear@93: done:
nuclear@93: 	blk_close(bdev);
nuclear@93: 	return res;
nuclear@90: }
nuclear@88: 
nuclear@94: static int read_superblock(struct filesys *fs)
nuclear@88: {
nuclear@94: 	struct superblock *sb = fs->sb;
nuclear@94: 
nuclear@93: 	/* read superblock and verify */
nuclear@94: 	if(blk_read(fs->bdev, 1, 1, sb) == -1) {
nuclear@93: 		printf("failed to read superblock\n");
nuclear@93: 		return -EIO;
nuclear@93: 	}
nuclear@93: 	if(sb->magic != MAGIC) {
nuclear@93: 		printf("invalid magic\n");
nuclear@93: 		return -EINVAL;
nuclear@93: 	}
nuclear@93: 	if(sb->ver > FS_VER) {
nuclear@93: 		printf("invalid version: %d\n", sb->ver);
nuclear@93: 		return -EINVAL;
nuclear@93: 	}
nuclear@93: 	if(sb->blksize != BLKSZ) {
nuclear@93: 		printf("invalid block size: %d\n", sb->blksize);
nuclear@93: 		return -EINVAL;
nuclear@93: 	}
nuclear@89: 
nuclear@93: 	/* allocate and populate in-memory bitmaps */
nuclear@93: 	if(!(sb->ibm = malloc(sb->ibm_count * sb->blksize))) {
nuclear@93: 		return -ENOMEM;
nuclear@88: 	}
nuclear@94: 	if(blk_read(fs->bdev, sb->ibm_start, sb->ibm_count, sb->ibm) == -1) {
nuclear@93: 		printf("failed to read inode bitmap\n");
nuclear@93: 		free(sb->ibm);
nuclear@93: 		return -EIO;
nuclear@93: 	}
nuclear@93: 	if(!(sb->bm = malloc(sb->bm_count * sb->blksize))) {
nuclear@93: 		free(sb->ibm);
nuclear@93: 		return -ENOMEM;
nuclear@93: 	}
nuclear@94: 	if(blk_read(fs->bdev, sb->bm_start, sb->bm_count, sb->bm) == -1) {
nuclear@93: 		printf("failed to read block bitmap\n");
nuclear@93: 		free(sb->ibm);
nuclear@93: 		free(sb->bm);
nuclear@93: 		return -EIO;
nuclear@93: 	}
nuclear@93: 
nuclear@94: 	/* read the root inode */
nuclear@94: 	if(!(sb->root = malloc(sizeof *sb->root))) {
nuclear@94: 		free(sb->ibm);
nuclear@94: 		free(sb->bm);
nuclear@94: 		return -ENOMEM;
nuclear@94: 	}
nuclear@94: 	if(get_inode(fs, sb->root_ino, sb->root) == -1) {
nuclear@94: 		printf("failed to read root inode\n");
nuclear@94: 		return -1;
nuclear@94: 	}
nuclear@94: 
nuclear@93: 	return 0;
nuclear@88: }
nuclear@94: 
nuclear@94: static int write_superblock(struct filesys *fs)
nuclear@94: {
nuclear@94: 	struct superblock *sb = fs->sb;
nuclear@94: 
nuclear@94: 	/* write back any changes in the root inode */
nuclear@94: 	if(put_inode(fs, sb->root) == -1) {
nuclear@94: 		return -1;
nuclear@94: 	}
nuclear@94: 	/* write back the block bitmap */
nuclear@94: 	if(blk_write(fs->bdev, sb->bm_start, sb->bm_count, sb->bm) == -1) {
nuclear@94: 		return -1;
nuclear@94: 	}
nuclear@94: 	/* write back the inode bitmap */
nuclear@94: 	if(blk_write(fs->bdev, sb->ibm_start, sb->ibm_count, sb->ibm) == -1) {
nuclear@94: 		return -1;
nuclear@94: 	}
nuclear@94: 	return 0;
nuclear@94: }
nuclear@94: 
nuclear@94: /* number of inodes in a block */
nuclear@94: #define BLK_INODES		(BLKSZ / sizeof(struct inode))
nuclear@94: 
nuclear@94: /* copy the requested inode from the disk, into the buffer passed in the last arg */
nuclear@94: static int get_inode(struct filesys *fs, int ino, struct inode *inode)
nuclear@94: {
nuclear@94: 	struct inode *buf = malloc(BLKSZ);
nuclear@94: 	assert(buf);
nuclear@94: 
nuclear@94: 	if(blk_read(fs->bdev, fs->sb->itbl_start + ino / BLK_INODES, 1, buf) == -1) {
nuclear@94: 		free(buf);
nuclear@94: 		return -1;
nuclear@94: 	}
nuclear@94: 	memcpy(inode, buf + ino % BLK_INODES, sizeof *inode);
nuclear@94: 	free(buf);
nuclear@94: 	return 0;
nuclear@94: }
nuclear@94: 
nuclear@94: /* write the inode to the disk */
nuclear@94: static int put_inode(struct filesys *fs, struct inode *inode)
nuclear@94: {
nuclear@94: 	struct inode *buf = malloc(BLKSZ);
nuclear@94: 	assert(buf);
nuclear@94: 
nuclear@94: 	if(blk_read(fs->bdev, fs->sb->itbl_start + inode->ino / BLK_INODES, 1, buf) == -1) {
nuclear@94: 		free(buf);
nuclear@94: 		return -1;
nuclear@94: 	}
nuclear@94: 	memcpy(buf + inode->ino % BLK_INODES, inode, sizeof *inode);
nuclear@94: 
nuclear@94: 	if(blk_write(fs->bdev, fs->sb->itbl_start + inode->ino / BLK_INODES, 1, buf) == -1) {
nuclear@94: 		free(buf);
nuclear@94: 		return -1;
nuclear@94: 	}
nuclear@94: 	free(buf);
nuclear@94: 	return 0;
nuclear@94: }