Make /bin/pwd almost conform to IEEE 1003.1

- Make 'pwd -L' fall back to 'pwd -P' if PWD is incorrect.
- Ignore PWD if it contains "/./" or "/../".
- Garbage collect some redundant code.
It is still non-conformant because posix mandates that the default
be 'pwd -L' (aka ksh), not 'pwd -P' (historic practise everywhere else).
Changing the default will break too much...

bin/pwd/pwd.1

@@ -1,4 +1,4 @@
-.\"	$NetBSD: pwd.1,v 1.22 2003/08/07 09:05:25 agc Exp $
+.\"	$NetBSD: pwd.1,v 1.23 2003/10/30 13:52:23 dsl Exp $
 .\"
 .\" Copyright (c) 1990, 1993
 .\"	The Regents of the University of California.  All rights reserved.
@@ -32,7 +32,7 @@
 .\"
 .\"     @(#)pwd.1	8.2 (Berkeley) 4/28/95
 .\"
-.Dd November 2, 1998
+.Dd October 30, 2003
 .Dt PWD 1
 .Os
 .Sh NAME
@@ -49,15 +49,25 @@ the standard output.
 The following options are available:
 .Bl -tag -width indent
 .It Fl L
-Print the logical path to the current working directory, as indicated
+If the
-by the shell in the environment variable
+.Ev PWD
-.Ev PWD ,
+environment variable is an absolute pathname that contains
-if possible.
+neither "/./" nor "/../" and references the current directory, then
+.Ev PWD
+is assumed to be the name of the current directory.
 .It Fl P
 Print the physical path to the current working directory, with symbolic
 links in the path resolved.
-This is the default.
 .El
+.Pp
+The default for the
+.Nm
+command is
+.Fl P .
+.Pp
+.Nm
+is usually provided as a shell builtin (which may have a different
+default).
 .Sh EXIT STATUS
 The
 .Nm
@@ -65,13 +75,18 @@ utility exits 0 on success, and \*[Gt]0 if an error occurs.
 .Sh SEE ALSO
 .Xr cd 1 ,
 .Xr csh 1 ,
+.Xr ksh 1 ,
+.Xr sh 1 ,
 .Xr getcwd 3
 .Sh STANDARDS
 The
 .Nm
 utility is expected to be conforming to
-.St -p1003.2 .
+.St -p1003.1 ,
-The options are extensions to the standard.
+except that the default is
+.Fl P
+not
+.Fl L .
 .Sh BUGS
 In
 .Xr csh 1
@@ -80,3 +95,13 @@ the command
 is always faster (although it can give a different answer in the rare case
 that the current directory or a containing directory was moved after
 the shell descended into it).
+.Pp
+.Nm
+.Fl L
+relies on the filesystem having unique inode numbers.
+If this is not true (eg msdos) then
+.Nm
+.Fl L
+may fail to detect that
+.Ev PWD
+is incorrect.

bin/pwd/pwd.c

@@ -1,4 +1,4 @@
-/* $NetBSD: pwd.c,v 1.18 2003/09/14 19:20:23 jschauma Exp $ */
+/* $NetBSD: pwd.c,v 1.19 2003/10/30 13:52:23 dsl Exp $ */
 
 /*
  * Copyright (c) 1991, 1993, 1994
@@ -39,7 +39,7 @@ __COPYRIGHT("@(#) Copyright (c) 1991, 1993, 1994\n\
 #if 0
 static char sccsid[] = "@(#)pwd.c	8.3 (Berkeley) 4/1/94";
 #else
-__RCSID("$NetBSD: pwd.c,v 1.18 2003/09/14 19:20:23 jschauma Exp $");
+__RCSID("$NetBSD: pwd.c,v 1.19 2003/10/30 13:52:23 dsl Exp $");
 #endif
 #endif /* not lint */
 
@@ -53,13 +53,17 @@ __RCSID("$NetBSD: pwd.c,v 1.18 2003/09/14 19:20:23 jschauma Exp $");
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
-#include <vis.h>
 
-int	stdout_ok;			/* stdout connected to a terminal */
+static char *getcwd_logical(void);
-
-static char *getcwd_logical(char *, size_t);
 static void usage(void);
-int main(int, char *[]);
+
+/*
+ * Note that EEE Std 1003.1, 2003 requires that the default be -L.
+ * This is inconsistent with the historic behaviour of everything
+ * except the ksh builtin.
+ * To avoid breaking scripts the default has been kept as -P.
+ * (Some scripts run /bin/pwd in order to get 'pwd -P'.)
+ */
 
 int
 main(int argc, char *argv[])
@@ -69,7 +73,7 @@ main(int argc, char *argv[])
 
 	setprogname(argv[0]);
 	lFlag = 0;
-	while ((ch = getopt(argc, argv, "LP")) != -1)
+	while ((ch = getopt(argc, argv, "LP")) != -1) {
 		switch (ch) {
 		case 'L':
 			lFlag = 1;
@@ -81,6 +85,7 @@ main(int argc, char *argv[])
 		default:
 			usage();
 		}
+	}
 	argc -= optind;
 	argv += optind;
 
@@ -88,15 +93,15 @@ main(int argc, char *argv[])
 		usage();
 
 	if (lFlag)
-		p = getcwd_logical(NULL, 0);
+		p = getcwd_logical();
 	else
+		p = NULL;
+	if (p == NULL)
 		p = getcwd(NULL, 0);
 
 	if (p == NULL)
 		err(EXIT_FAILURE, NULL);
 
-	stdout_ok = isatty(STDOUT_FILENO);
-
 	(void)printf("%s\n", p);
 
 	exit(EXIT_SUCCESS);
@@ -104,42 +109,26 @@ main(int argc, char *argv[])
 }
 
 static char *
-getcwd_logical(char *pt, size_t size)
+getcwd_logical(void)
 {
 	char *pwd;
-	size_t pwdlen;
+	struct stat s_pwd, s_dot;
-	dev_t dev;
-	ino_t ino;
-	struct stat s;
 
 	/* Check $PWD -- if it's right, it's fast. */
-	if ((pwd = getenv("PWD")) != NULL && pwd[0] == '/') {
+	pwd = getenv("PWD");
-		if (stat(pwd, &s) != -1) {
+	if (pwd == NULL)
-			dev = s.st_dev;
+		return NULL;
-			ino = s.st_ino;
+	if (pwd[0] != '/')
-			if (stat(".", &s) != -1 && dev == s.st_dev &&
+		return NULL;
-			    ino == s.st_ino) {
+	if (strstr(pwd, "/./") != NULL)
-				pwdlen = strlen(pwd);
+		return NULL;
-				if (pt) {
+	if (strstr(pwd, "/../") != NULL)
-					if (!size) {
+		return NULL;
-						errno = EINVAL;
+	if (stat(pwd, &s_pwd) == -1 || stat(".", &s_dot) == -1)
-						return (NULL);
+		return NULL;
-					}
+	if (s_pwd.st_dev != s_dot.st_dev || s_pwd.st_ino != s_dot.st_ino)
-					if (pwdlen + 1 > size) {
+		return NULL;
-						errno = ERANGE;
+	return pwd;
-						return (NULL);
-					}
-				} else if ((pt = malloc(pwdlen + 1)) == NULL)
-					return (NULL);
-				(void)memmove(pt, pwd, pwdlen);
-				pt[pwdlen] = '\0';
-				return (pt);
-			}
-		}
-	} else
-		errno = ENOENT;
-
-	return (NULL);
 }
 
 static void