Add original unix v6

source/s2/passwd.c

@@ -0,0 +1,151 @@
+/*
+ * enter a password in the password file
+ * this program should be suid with owner
+ * with an owner with write permission on /etc/passwd
+ */
+char	*tfile	{ "/tmp/ptmp" };
+char	*pfile	{ "/etc/passwd" };
+int	tbuf[259];
+int	pbuf[259];
+
+main(argc, argv)
+char *argv[];
+{
+	register u, c;
+	register char *p;
+
+	if(argc != 3) {
+		write(2, "Usage: passwd user password\n", 28);
+		goto bex;
+	}
+	signal(1, 1);
+	signal(2, 1);
+	signal(3, 1);
+
+	if(stat(tfile, tbuf+20) >= 0) {
+		write(2, "Temporary file busy -- try again\n", 33);
+		goto bex;
+	}
+	tbuf[0] = creat(tfile, 0600);
+	if(tbuf[0] < 0) {
+		write(2, "Cannot create temporary file\n", 29);
+		goto bex;
+	}
+	pbuf[0] = open(pfile, 0);
+	if(pbuf[0] < 0) {
+		write(2, "Cannot open /etc/passwd\n", 24);
+		goto out;
+	}
+	goto l1;
+
+/*
+ * skip to beginning of next line
+ */
+
+skip:
+	while(c != '\n') {
+		if(c < 0)
+			goto ill;
+		c = getc(pbuf);
+		putc(c, tbuf);
+	}
+
+/*
+ * compare user names
+ */
+
+l1:
+	c = getc(pbuf);
+	putc(c, tbuf);
+	if(c < 0) {
+		write(2, "User name not found in password file\n", 37);
+		goto out;
+	}
+	p = argv[1];
+	while(c != ':') {
+		if(*p++ != c)
+			goto skip;
+		c = getc(pbuf);
+		putc(c, tbuf);
+	}
+	if(*p)
+		goto skip;
+/*
+ * skip old password
+ */
+	do {
+		c = getc(pbuf);
+		if(c < 0)
+			goto ill;
+	} while(c != ':');
+
+/*
+ * copy in new password
+ */
+	p = argv[2];
+	for(c=0; c<9; c++)
+		if(*p++ == 0)
+			break;
+	*--p = 0;
+	if(p != argv[2])
+		p = crypt(argv[2]);
+	while(*p)
+		putc(*p++, tbuf);
+	putc(':', tbuf);
+
+/*
+ * validate uid
+ */
+
+	u = 0;
+	do {
+		c = getc(pbuf);
+		putc(c, tbuf);
+		if(c >= '0' && c <= '9')
+			u = u*10 + c-'0';
+		if(c < 0)
+			goto ill;
+	} while(c != ':');
+	c = getuid() & 0377;
+	if(c != 0 && c != u) {
+		write(2, "Permission denied\n", 18);
+		goto out;
+	}
+
+/*
+ * copy out and back
+ */
+
+	for(;;) {
+		c = getc(pbuf);
+		if(c < 0) {
+			fflush(tbuf);
+			close(pbuf[0]);
+			close(tbuf[0]);
+			tbuf[0] = open(tfile, 0);
+			if(tbuf[0] < 0) {
+				write(2, "Urk\n", 4);
+				goto out;
+			}
+			pbuf[0] = creat(pfile, 0644);
+			if(pbuf[0] < 0) {
+				write(2, "Cannot create /etc/passwd\n", 26);
+				goto out;
+			}
+			while((c = read(tbuf[0], tbuf+1, 512)) > 0)
+				write(pbuf[0], tbuf+1, c);
+			unlink(tfile);
+			exit(0);
+		}
+		putc(c, tbuf);
+	}
+
+ill:
+	write(2, "Password file illformed\n", 24);
+
+out:
+	unlink(tfile);
+
+bex:
+	exit(1);
+}