Add generation number randomization. Newly created filesystems wil now

automatically have random generation numbers. The kenel way of handling those
also changed. Further it is advised to run fsirand on all your nfs exported
filesystems. the code is mostly copied from OpenBSD, with the randomization
chanegd to use /dev/urandom
Reviewed by:	Garrett
Obtained from: OpenBSD

2 files changed, 39 insertions, 6 deletions

diff --git a/sbin/newfs/Makefile b/sbin/newfs/Makefile
index ed9ad9d..d44fdba 100644
--- a/sbin/newfs/Makefile
+++ b/sbin/newfs/Makefile
@@ -6,7 +6,7 @@ MAN8=	newfs.8
 
 MOUNT=	${.CURDIR}/../mount
 CFLAGS+= -D_NEW_VFSCONF
-CFLAGS+=-DMFS -I${MOUNT}
+CFLAGS+=-DMFS -DFSIRAND -I${MOUNT}
 .PATH:	${MOUNT} ${.CURDIR}/../disklabel
 
 LINKS=	${BINDIR}/newfs ${BINDIR}/mount_mfs
diff --git a/sbin/newfs/mkfs.c b/sbin/newfs/mkfs.c
index ab4713d..63ad1bf 100644
--- a/sbin/newfs/mkfs.c
+++ b/sbin/newfs/mkfs.c
@@ -86,8 +86,6 @@ extern int	realsectorsize;	/* bytes/sector in hardware*/
 extern int	rpm;		/* revolutions/minute of drive */
 extern int	interleave;	/* hardware sector interleave */
 extern int	trackskew;	/* sector 0 skew, per track */
-extern int	headswitch;	/* head switch time, usec */
-extern int	trackseek;	/* track-to-track seek, usec */
 extern int	fsize;		/* fragment size */
 extern int	bsize;		/* block size */
 extern int	cpg;		/* cylinders/cylinder group */
@@ -121,6 +119,10 @@ union {
 
 struct dinode zino[MAXBSIZE / sizeof(struct dinode)];
 
+#ifdef FSIRAND
+long	fsi_random __P((void));
+#endif
+
 int	fsi, fso;
 daddr_t	alloc();
 static int charsperline();
@@ -591,8 +593,6 @@ next:
 	sblock.fs_rotdelay = rotdelay;
 	sblock.fs_minfree = minfree;
 	sblock.fs_maxcontig = maxcontig;
-	sblock.fs_headswitch = headswitch;
-	sblock.fs_trkseek = trackseek;
 	sblock.fs_maxbpg = maxbpg;
 	sblock.fs_rps = rpm / 60;
 	sblock.fs_optim = opt;
@@ -604,6 +604,11 @@ next:
 	sblock.fs_fmod = 0;
 	sblock.fs_ronly = 0;
 	sblock.fs_clean = 1;
+#ifdef FSIRAND
+	sblock.fs_id[0] = (long)utime;
+	sblock.fs_id[1] = fsi_random();
+#endif
+
 	/*
 	 * Dump out summary information about file system.
 	 */
@@ -751,9 +756,14 @@ initcg(cylno, utime)
 			setbit(cg_inosused(&acg), i);
 			acg.cg_cs.cs_nifree--;
 		}
-	for (i = 0; i < sblock.fs_ipg / INOPF(&sblock); i += sblock.fs_frag)
+	for (i = 0; i < sblock.fs_ipg / INOPF(&sblock); i += sblock.fs_frag) {
+#ifdef FSIRAND
+		for (j = 0; j < sblock.fs_bsize / sizeof(struct dinode); j++)
+			zino[j].di_gen = fsi_random();
+#endif
 		wtfs(fsbtodb(&sblock, cgimin(&sblock, cylno) + i),
 		    sblock.fs_bsize, (char *)zino);
+	}
 	if (cylno > 0) {
 		/*
 		 * In cylno 0, beginning space is reserved
@@ -1057,6 +1067,9 @@ iput(ip, ino)
 	daddr_t d;
 	int c;
 
+#ifdef FSIRAND
+	ip->di_gen = fsi_random();
+#endif
 	c = ino_to_cg(&sblock, ino);
 	rdfs(fsbtodb(&sblock, cgtod(&sblock, 0)), sblock.fs_cgsize,
 	    (char *)&acg);
@@ -1336,3 +1349,23 @@ charsperline()
 		columns = 80;	/* last resort */
 	return columns;
 }
+
+#ifdef FSIRAND
+long
+fsi_random(void) {
+	static int fd = -1;
+	long    ret;
+ 
+	if (fd == -1) {
+		if ((fd = open("/dev/urandom", O_RDONLY)) == -1) { 
+			perror("open /dev/urandom");
+			exit(1);
+		}
+	}
+	if (read(fd, &ret, sizeof(ret)) != sizeof(ret)) {
+		perror("read /dev/urandom");
+		exit(1);
+	}
+	return(ret);
+}
+#endif