do not open the device for writing if not needed to; millert@ ok & help

1 files changed, 21 insertions, 9 deletions

diff --git a/sbin/tunefs/tunefs.c b/sbin/tunefs/tunefs.c
index 952dc6e0b01..f73aed3f6a2 100644
--- a/sbin/tunefs/tunefs.c
+++ b/sbin/tunefs/tunefs.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: tunefs.c,v 1.15 2001/11/05 07:39:17 mpech Exp $	*/
+/*	$OpenBSD: tunefs.c,v 1.16 2001/12/04 07:23:58 mickey Exp $	*/
 /*	$NetBSD: tunefs.c,v 1.10 1995/03/18 15:01:31 cgd Exp $	*/
 
 /*
@@ -44,7 +44,7 @@ static char copyright[] =
 #if 0
 static char sccsid[] = "@(#)tunefs.c	8.2 (Berkeley) 4/19/94";
 #else
-static char rcsid[] = "$OpenBSD: tunefs.c,v 1.15 2001/11/05 07:39:17 mpech Exp $";
+static char rcsid[] = "$OpenBSD: tunefs.c,v 1.16 2001/12/04 07:23:58 mickey Exp $";
 #endif
 #endif /* not lint */
 
@@ -74,12 +74,12 @@ union {
 } sbun;
 #define	sblock sbun.sb
 
-int fi;
+int fi = -1;
 long dev_bsize = 1;
 
 void bwrite(daddr_t, char *, int);
 int bread(daddr_t, char *, int);
-void getsb(struct fs *, char *);
+void getsb(struct fs *, char *, int);
 void usage __P((void));
 void printfs __P((void));
 
@@ -118,7 +118,6 @@ again:
 	}
 	if (!S_ISBLK(st.st_mode) && !S_ISCHR(st.st_mode))
 		errx(10, "%s: not a block or character device", special);
-	getsb(&sblock, special);
 	for (; argc > 0 && argv[0][0] == '-'; argc--, argv++) {
 		for (cp = &argv[0][1]; *cp; cp++)
 			switch (*cp) {
@@ -128,10 +127,12 @@ again:
 				continue;
 
 			case 'p':
+				getsb(&sblock, special, O_RDONLY);
 				printfs();
 				return (0);
 
 			case 'a':
+				getsb(&sblock, special, O_RDWR);
 				name = "maximum contiguous block count";
 				if (argc < 1)
 					errx(10, "-a: missing %s", name);
@@ -146,6 +147,7 @@ again:
 				continue;
 
 			case 'd':
+				getsb(&sblock, special, O_RDWR);
 				name =
 				   "rotational delay between contiguous blocks";
 				if (argc < 1)
@@ -158,6 +160,7 @@ again:
 				continue;
 
 			case 'e':
+				getsb(&sblock, special, O_RDWR);
 				name =
 				  "maximum blocks per file in a cylinder group";
 				if (argc < 1)
@@ -173,6 +176,7 @@ again:
 				continue;
 
 			case 'f':
+				getsb(&sblock, special, O_RDWR);
 				name = "average file size";
 				if (argc < 1)
 					errx(10, "-f: missing %s", name);
@@ -187,6 +191,7 @@ again:
 				continue;
 
 			case 'm':
+				getsb(&sblock, special, O_RDWR);
 				name = "minimum percentage of free space";
 				if (argc < 1)
 					errx(10, "-m: missing %s", name);
@@ -206,6 +211,7 @@ again:
 				continue;
 
 			case 'n':
+				getsb(&sblock, special, O_RDWR);
 				name = "expected number of files per directory";
 				if (argc < 1)
 					errx(10, "-n: missing %s", name);
@@ -224,6 +230,7 @@ again:
 				      " how to enable soft updates.");
 
 			case 'o':
+				getsb(&sblock, special, O_RDWR);
 				name = "optimization preference";
 				if (argc < 1)
 					errx(10, "-o: missing %s", name);
@@ -264,7 +271,9 @@ again:
 		for (i = 0; i < sblock.fs_ncg; i++)
 			bwrite(fsbtodb(&sblock, cgsblock(&sblock, i)),
 			    (char *)&sblock, SBSIZE);
-	close(fi);
+	if (close(fi))
+		err(1, "close: %s", special);
+
 	return (0);
 }
 
@@ -288,18 +297,21 @@ usage()
 }
 
 void
-getsb(fs, file)
+getsb(fs, file, flags)
 	struct fs *fs;
 	char *file;
+	int flags;
 {
 
-	fi = open(file, 2);
+	if (fi >= 0)
+		return;
+	fi = open(file, flags);
 	if (fi < 0)
 		err(3, "cannot open %s", file);
 	if (bread((daddr_t)SBOFF, (char *)fs, SBSIZE))
 		err(4, "%s: bad super block", file);
 	if (fs->fs_magic != FS_MAGIC)
-		err(5, "%s: bad magic number", file);
+		errx(5, "%s: bad magic number", file);
 	dev_bsize = fs->fs_fsize / fsbtodb(fs, 1);
 }