Add facility to read one, or a string of, cylinger groups.

lib/libufs/Makefile

@@ -1,7 +1,7 @@
 # $FreeBSD$
 
 LIB=	ufs
-SRCS=	block.c inode.c sblock.c type.c
+SRCS=	block.c cgroup.c inode.c sblock.c type.c
 INCS=	libufs.h
 CFLAGS+= -I${.CURDIR} -D_LIBUFS
 .if defined(LIBUFS_DEBUG)

lib/libufs/cgroup.c

@@ -0,0 +1,72 @@
+/*
+ * Copyright (c) 2003 Juli Mallett.  All rights reserved.
+ *
+ * This software was written by Juli Mallett <jmallett@FreeBSD.org> for the
+ * FreeBSD project.  Redistribution and use in source and binary forms, with
+ * or without modification, are permitted provided that the following
+ * conditions are met:
+ *
+ * 1. Redistribution of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistribution in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
+ * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <sys/param.h>
+#include <sys/mount.h>
+#include <sys/disklabel.h>
+#include <sys/stat.h>
+
+#include <ufs/ufs/ufsmount.h>
+#include <ufs/ufs/dinode.h>
+#include <ufs/ffs/fs.h>
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <libufs.h>
+
+int
+cgread(struct uufsd *disk)
+{
+	return cgread1(disk, disk->d_ccg++);
+}
+
+int
+cgread1(struct uufsd *disk, int c)
+{
+	struct fs *fs;
+	off_t ccg;
+
+	fs = &disk->d_fs;
+
+	if (c >= fs->fs_ncg) {
+		return 0;
+	}
+	ccg = fsbtodb(fs, cgtod(fs, c)) * disk->d_bsize;
+	if (bread(disk, fsbtodb(fs, cgtod(fs, c)), disk->d_cgunion.d_buf,
+	    fs->fs_bsize) == -1) {
+		ERROR(disk, "unable to read cylinder group");
+		return -1;
+	}
+	return 1;
+}

lib/libufs/libufs.h

@@ -79,10 +79,17 @@ struct uufsd {
 		char d_sb[MAXBSIZE];
 				/* superblock as buffer */
 	} d_sbunion;
+	union {
+		struct cg d_cg;	/* cylinder group */
+		char d_buf[MAXBSIZE];
+				/* cylinder group storage */
+	} d_cgunion;
+	int d_ccg;		/* current cylinder group */
 	const char *d_error;	/* human readable disk error */
 	int d_mine;		/* internal flags */
 #define	d_fs	d_sbunion.d_fs
 #define	d_sb	d_sbunion.d_sb
+#define	d_cg	d_cgunion.d_cg
 };
 
 __BEGIN_DECLS
@@ -97,6 +104,12 @@ __BEGIN_DECLS
 ssize_t bread(struct uufsd *, ufs2_daddr_t, void *, size_t);
 ssize_t bwrite(struct uufsd *, ufs2_daddr_t, const void *, size_t);
 
+/*
+ * cgroup.c
+ */
+int cgread(struct uufsd *);
+int cgread1(struct uufsd *, int);
+
 /*
  * inode.c
  */

lib/libufs/type.c

@@ -141,6 +141,7 @@ again:	if (stat(name, &st) < 0) {
 	}
 
 	disk->d_bsize = 1;
+	disk->d_ccg = 0;
 	disk->d_fd = fd;
 	disk->d_inoblock = NULL;
 	disk->d_inomin = 0;