From c337c37259502bbcb3efde45ca7db82f927ff512 Mon Sep 17 00:00:00 2001
From: guido <guido@FreeBSD.org>
Date: Sun, 23 Mar 1997 20:08:22 +0000
Subject: 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

---
 sbin/newfs/mkfs.c | 43 ++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 38 insertions(+), 5 deletions(-)

(limited to 'sbin/newfs/mkfs.c')

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
-- 
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