Add original unix v6

source/s2/umount.c

@@ -0,0 +1,53 @@
+#define	NMOUNT	16
+#define	NAMSIZ	32
+
+struct mtab {
+	char	file[NAMSIZ];
+	char	spec[NAMSIZ];
+} mtab[NMOUNT];
+
+main(argc, argv)
+char **argv;
+{
+	register struct mtab *mp;
+	register char *p1, *p2;
+	int mf;
+
+	sync();
+	mf = open("/etc/mtab", 0);
+	read(mf, mtab, NMOUNT*2*NAMSIZ);
+	if(argc != 2) {
+		printf("arg count\n");
+		return;
+	}
+	if (umount(argv[1]) < 0) {
+		perror("umount");
+		return;
+	}
+	p1 = argv[1];
+	while(*p1++)
+		;
+	p1--;
+	while(*--p1 == '/')
+		*p1 = '\0';
+	while(p1 > argv[1] && *--p1 != '/')
+		;
+	if(*p1 == '/')
+		p1++;
+	argv[1] = p1;
+	for (mp = mtab; mp < &mtab[NMOUNT]; mp++) {
+		p1 = argv[1];
+		p2 = &mp->spec[0];
+		while (*p1++ == *p2)
+			if (*p2++ == 0) {
+				for (p1 = mp->file; p1 < &mp->file[NAMSIZ*2];)
+					*p1++ = 0;
+				mp = &mtab[NMOUNT];
+				while ((--mp)->file[0] == 0);
+				mf = creat("/etc/mtab", 0644);
+				write(mf, mtab, (mp-mtab+1)*2*NAMSIZ);
+				return;
+			}
+	}
+	printf("%s not in mount table\n", argv[1]);
+}