library.c

早期freebsd实现

		printf("BLOCK INFOS\n");
		for (_bip = bip, i=0; i < *bcount; ++_bip, ++i)
			PRINT_BINFO(_bip);
	}
#endif
	*blocks = bip;
	return (0);

err0:	*bcount = 0;
	return (-1);
	
}

/* 
 * This will parse a partial segment and fill in BLOCK_INFO structures
 * for each block described in the segment summary.  It will not include
 * blocks or inodes from files with new version numbers.  
 */
void
add_blocks (fsp, bip, countp, sp, seg_buf, segaddr, psegaddr)
	FS_INFO *fsp;		/* pointer to super block */
	BLOCK_INFO *bip;	/* Block info array */
	int *countp;		/* IN/OUT: number of blocks in array */
	SEGSUM	*sp;		/* segment summmary pointer */
	caddr_t seg_buf;	/* buffer containing segment */
	daddr_t segaddr;	/* address of this segment */
	daddr_t psegaddr;	/* address of this partial segment */
{
	IFILE	*ifp;
	FINFO	*fip;
	caddr_t	bp;
	daddr_t	*dp, *iaddrp;
	int db_per_block, i, j;
	u_long page_size;

#ifdef VERBOSE
	printf("FILE INFOS\n");
#endif
	db_per_block = fsbtodb(&fsp->fi_lfs, 1);
	page_size = fsp->fi_lfs.lfs_bsize;
	bp = seg_buf + datobyte(fsp, psegaddr - segaddr) + LFS_SUMMARY_SIZE;
	bip += *countp;
	psegaddr += bytetoda(fsp, LFS_SUMMARY_SIZE);
	iaddrp = (daddr_t *)((caddr_t)sp + LFS_SUMMARY_SIZE);
	--iaddrp;
	for (fip = (FINFO *)(sp + 1), i = 0; i < sp->ss_nfinfo;
	    ++i, fip = (FINFO *)(&fip->fi_blocks[fip->fi_nblocks])) {

		ifp = IFILE_ENTRY(&fsp->fi_lfs, fsp->fi_ifilep, fip->fi_ino);
		PRINT_FINFO(fip, ifp);
		if (ifp->if_version > fip->fi_version)
			continue;
		dp = &(fip->fi_blocks[0]);
		for (j = 0; j < fip->fi_nblocks; j++, dp++) {
			while (psegaddr == *iaddrp) {
				psegaddr += db_per_block;
				bp += page_size;
				--iaddrp;
			}
			bip->bi_inode = fip->fi_ino;
			bip->bi_lbn = *dp;
			bip->bi_daddr = psegaddr;
			bip->bi_segcreate = (time_t)(sp->ss_create);
			bip->bi_bp = bp;
			bip->bi_version = ifp->if_version;
			psegaddr += db_per_block;
			bp += page_size;
			++bip;
			++(*countp);
		}
	}
}

/*
 * For a particular segment summary, reads the inode blocks and adds
 * INODE_INFO structures to the array.  Returns the number of inodes
 * actually added.
 */
void
add_inodes (fsp, bip, countp, sp, seg_buf, seg_addr)
	FS_INFO *fsp;		/* pointer to super block */
	BLOCK_INFO *bip;	/* block info array */
	int *countp;		/* pointer to current number of inodes */
	SEGSUM *sp;		/* segsum pointer */
	caddr_t	seg_buf;	/* the buffer containing the segment's data */
	daddr_t	seg_addr;	/* disk address of seg_buf */
{
	struct dinode *di;
	struct lfs *lfsp;
	IFILE *ifp;
	BLOCK_INFO *bp;
	daddr_t	*daddrp;
	ino_t inum;
	int i;
	
	if (sp->ss_ninos <= 0)
		return;
	
	bp = bip + *countp;
	lfsp = &fsp->fi_lfs;
#ifdef VERBOSE
	(void) printf("INODES:\n");
#endif
	daddrp = (daddr_t *)((caddr_t)sp + LFS_SUMMARY_SIZE);
	for (i = 0; i < sp->ss_ninos; ++i) {
		if (i % INOPB(lfsp) == 0) {
			--daddrp;
			di = (struct dinode *)(seg_buf +
			    ((*daddrp - seg_addr) << fsp->fi_daddr_shift));
		} else 
			++di;
		
		inum = di->di_inumber;
		bp->bi_lbn = LFS_UNUSED_LBN;
		bp->bi_inode = inum;
		bp->bi_daddr = *daddrp;
		bp->bi_bp = di;
		bp->bi_segcreate = sp->ss_create;

		if (inum == LFS_IFILE_INUM) {
			bp->bi_version = 1;	/* Ifile version should be 1 */
			bp++;
			++(*countp);
			PRINT_INODE(1, bp);
		} else {
			ifp = IFILE_ENTRY(lfsp, fsp->fi_ifilep, inum);
			PRINT_INODE(ifp->if_daddr == *daddrp, bp);
			bp->bi_version = ifp->if_version;
			if (ifp->if_daddr == *daddrp) {
				bp++;
				++(*countp);
			} 
		}
	}
}

/*
 * Checks the summary checksum and the data checksum to determine if the
 * segment is valid or not.  Returns the size of the partial segment if it
 * is valid, * and 0 otherwise.  Use dump_summary to figure out size of the
 * the partial as well as whether or not the checksum is valid.
 */	 
int
pseg_valid (fsp, ssp)
	FS_INFO *fsp;   /* pointer to file system info */
	SEGSUM *ssp;	/* pointer to segment summary block */
{
	caddr_t	p;
	int i, nblocks;
	u_long *datap;

	if ((nblocks = dump_summary(&fsp->fi_lfs, ssp, 0, NULL)) <= 0 ||
	    nblocks > fsp->fi_lfs.lfs_ssize - 1)
		return(0);
		
	/* check data/inode block(s) checksum too */
	datap = (u_long *)malloc(nblocks * sizeof(u_long));
	p = (caddr_t)ssp + LFS_SUMMARY_SIZE;
	for (i = 0; i < nblocks; ++i) {
		datap[i] = *((u_long *)p);
		p += fsp->fi_lfs.lfs_bsize;
	}
	if (cksum ((void *)datap, nblocks * sizeof(u_long)) != ssp->ss_datasum)
		return (0);
	
	return (nblocks);
}


/* #define MMAP_SEGMENT */
/* 
 * read a segment into a memory buffer
 */
int
mmap_segment (fsp, segment, segbuf, use_mmap)
	FS_INFO *fsp;		/* file system information */
	int segment;		/* segment number */
	caddr_t *segbuf;	/* pointer to buffer area */
	int use_mmap;		/* mmap instead of read */
{
	struct lfs *lfsp;
	int fid;		/* fildes for file system device */
	daddr_t seg_daddr;	/* base disk address of segment */
	off_t seg_byte;
	size_t ssize;
	char mntfromname[MNAMELEN+2];

	lfsp = &fsp->fi_lfs;

	/* get the disk address of the beginning of the segment */
	seg_daddr = sntoda(lfsp, segment);
	seg_byte = datobyte(fsp, seg_daddr);
	ssize = seg_size(lfsp);

	strcpy(mntfromname, "/dev/r");
	strcat(mntfromname, fsp->fi_statfsp->f_mntfromname+5);

	if ((fid = open(mntfromname, O_RDONLY, (mode_t)0)) < 0) {
		err(0, "mmap_segment: bad open");
		return (-1);
	}

	if (use_mmap) {
		*segbuf = mmap ((caddr_t)0, seg_size(lfsp), PROT_READ,
		    0, fid, seg_byte);
		if (*(long *)segbuf < 0) {
			err(0, "mmap_segment: mmap failed");
			return (NULL);
		}
	} else {
#ifdef VERBOSE
		printf("mmap_segment\tseg_daddr: %lu\tseg_size: %lu\tseg_offset: %qu\n",
		    seg_daddr, ssize, seg_byte);
#endif
		/* malloc the space for the buffer */
		*segbuf = malloc(ssize);
		if (!*segbuf) {
			err(0, "mmap_segment: malloc failed");
			return(NULL);
		}

		/* read the segment data into the buffer */
		if (lseek (fid, seg_byte, SEEK_SET) != seg_byte) {
			err (0, "mmap_segment: bad lseek");
			free(*segbuf);
			return (-1);
		}
		
		if (read (fid, *segbuf, ssize) != ssize) {
			err (0, "mmap_segment: bad read");
			free(*segbuf);
			return (-1);
		}
	}
	close (fid);

	return (0);
}

void
munmap_segment (fsp, seg_buf, use_mmap)
	FS_INFO *fsp;		/* file system information */
	caddr_t seg_buf;	/* pointer to buffer area */
	int use_mmap;		/* mmap instead of read/write */
{
	if (use_mmap)
		munmap (seg_buf, seg_size(&fsp->fi_lfs));
	else
		free (seg_buf);
}


/*
 * USEFUL DEBUGGING TOOLS:
 */
void
print_SEGSUM (lfsp, p)
	struct lfs *lfsp;
	SEGSUM	*p;
{
	if (p)
		(void) dump_summary(lfsp, p, DUMP_ALL, NULL);
	else printf("0x0");
	fflush(stdout);
}

int
bi_compare(a, b)
	const void *a;
	const void *b;
{
	const BLOCK_INFO *ba, *bb;
	int diff;

	ba = a;
	bb = b;

	if (diff = (int)(ba->bi_inode - bb->bi_inode))
		return (diff);
	if (diff = (int)(ba->bi_lbn - bb->bi_lbn)) {
		if (ba->bi_lbn == LFS_UNUSED_LBN)
			return(-1);
		else if (bb->bi_lbn == LFS_UNUSED_LBN)
			return(1);
		else if (ba->bi_lbn < 0 && bb->bi_lbn >= 0)
			return(1);
		else if (bb->bi_lbn < 0 && ba->bi_lbn >= 0)
			return(-1);
		else
			return (diff);
	}
	if (diff = (int)(ba->bi_segcreate - bb->bi_segcreate))
		return (diff);
	diff = (int)(ba->bi_daddr - bb->bi_daddr);
	return (diff);
}	

int
bi_toss(dummy, a, b)
	const void *dummy;
	const void *a;
	const void *b;
{
	const BLOCK_INFO *ba, *bb;

	ba = a;
	bb = b;

	return(ba->bi_inode == bb->bi_inode && ba->bi_lbn == bb->bi_lbn);
}

void
toss(p, nump, size, dotoss, client)
	void *p;
	int *nump;
	size_t size;
	int (*dotoss) __P((const void *, const void *, const void *));
	void *client;
{
	int i;
	void *p1;

	if (*nump == 0)
		return;

	for (i = *nump; --i > 0;) {
		p1 = p + size;
		if (dotoss(client, p, p1)) {
			memmove(p, p1, i * size);
			--(*nump);
		} else 
			p += size;
	}
}