pwd bug

[utzoo!decvax!ittvax!swatt]

Fri Jan  8 21:22:38 EST 1982 (ittvax!freb)

[ ]	The command "pwd" will do strange things if any of the
	directories above the present one lack execute permission.  It
	will print some random string, but not exit with an error
	status.  Programs which do 'popen ("pwd", "r")' in order to get
	the current directory can get fooled.

	The reason is in several places "pwd" never checks the return
	status on certain system calls.

	The fix is:
	===============================================================
	cp /usr/src/cmd/pwd.c /tmp/upd.$$.tmp ; chmod +w /tmp/upd.$$.tmp
	ed - /tmp/upd.$$.tmp <<\!xxFUNNYxx
	34c
			/* @@@ check */
			if (chdir(dotdot)) {
				fprintf (stderr, "Cannot stat %s:%s\n", dotdot,
					 sys_errlist[errno]);
				exit (1);
			}
	.
	30c
				fprintf(stderr,"pwd: cannot open \"%s\":%s\n",
					dotdot, sys_errlist[errno]);
	.
	26c
			if (stat(dot, &d)) {
				fprintf (stderr, "Cannot stat \"%s\":%s\n",
					 dot, sys_errlist[errno]);
				exit (1);
			}
	.
	22c
		if (stat("/", &d)) {
			fprintf (stderr, "TERRIBLE ERROR: cannot stat \"/\"!:%s\n",
				 sys_errlist[errno]);
			exit (1);
		}
	.
	17a
	extern	errno;
	extern	char *sys_errlist[];

	.
	1c
	static char *sccsid = "@(#)pwd.c	4.2 (ITT) 01/08/82";
	.
	w
	q
	!xxFUNNYxx
	diff /usr/src/cmd/pwd.c /tmp/upd.$$.tmp >/tmp/upd.$$.dif
	if cmp - /tmp/upd.$$.dif <<\!xxFUNNYxx
	1c1
	< static char *sccsid = "@(#)pwd.c	4.1 (Berkeley) 10/1/80";
	---
	> static char *sccsid = "@(#)pwd.c	4.2 (ITT) 01/08/82";
	17a18,20
	> extern	errno;
	> extern	char *sys_errlist[];
	> 
	22c25,29
	< 	stat("/", &d);
	---
	> 	if (stat("/", &d)) {
	> 		fprintf (stderr, "TERRIBLE ERROR: cannot stat \"/\"!:%s\n",
	> 			 sys_errlist[errno]);
	> 		exit (1);
	> 	}
	26c33,37
	< 		stat(dot, &d);
	---
	> 		if (stat(dot, &d)) {
	> 			fprintf (stderr, "Cannot stat \"%s\":%s\n",
	> 				 dot, sys_errlist[errno]);
	> 			exit (1);
	> 		}
	30c41,42
	< 			fprintf(stderr,"pwd: cannot open ..\n");
	---
	> 			fprintf(stderr,"pwd: cannot open \"%s\":%s\n",
	> 				dotdot, sys_errlist[errno]);
	34c46,51
	< 		chdir(dotdot);
	---
	> 		/* @@@ check */
	> 		if (chdir(dotdot)) {
	> 			fprintf (stderr, "Cannot stat %s:%s\n", dotdot,
	> 				 sys_errlist[errno]);
	> 			exit (1);
	> 		}
	!xxFUNNYxx
	then
		: 'compare equal, ok'
		rm -f pwd.c
		cp /tmp/upd.$$.tmp pwd.c ; chmod a-w pwd.c
	else
		echo "Old source file not same version;" \
			"use diff listings by hand"
	fi
	rm -f /tmp/upd.$$.tmp /tmp/upd.$$.dif
	===============================================================