From c9c987cd35564912f5ff7c1895266127ea5cc3d9 Mon Sep 17 00:00:00 2001
From: Jilles Tjoelker <jilles@FreeBSD.org>
Date: Fri, 2 Jul 2010 22:17:13 +0000
Subject: [PATCH] sh: Use $PWD instead of getcwd() for the \w and \W prompt
 expansions.

This ensures that the logical working directory (which may include
symlinks) is shown and is similar to the default behaviour of the pwd
builtin.
---
 bin/sh/parser.c | 23 +++++++++++------------
 1 file changed, 11 insertions(+), 12 deletions(-)

diff --git a/bin/sh/parser.c b/bin/sh/parser.c
index d11007e55a4e..7f7f0d6a2556 100644
--- a/bin/sh/parser.c
+++ b/bin/sh/parser.c
@@ -1734,7 +1734,8 @@ getprompt(void *unused __unused)
 {
 	static char ps[PROMPTLEN];
 	char *fmt;
-	int i, j, trim;
+	const char *pwd;
+	int i, trim;
 	static char internal_error[] = "<internal prompt error>";
 
 	/*
@@ -1785,17 +1786,15 @@ getprompt(void *unused __unused)
 				 */
 			case 'W':
 			case 'w':
-				ps[i] = '\0';
-				getcwd(&ps[i], PROMPTLEN - i);
-				if (*fmt == 'W' && ps[i + 1] != '\0') {
-					/* Final path component only. */
-					trim = 1;
-					for (j = i; ps[j] != '\0'; j++)
-					  if (ps[j] == '/')
-						trim = j + 1;
-					memmove(&ps[i], &ps[trim],
-					    j - trim + 1);
-				}
+				pwd = lookupvar("PWD");
+				if (pwd == NULL)
+					pwd = "?";
+				if (*fmt == 'W' &&
+				    *pwd == '/' && pwd[1] != '\0')
+					strlcpy(&ps[i], strrchr(pwd, '/') + 1,
+					    PROMPTLEN - i);
+				else
+					strlcpy(&ps[i], pwd, PROMPTLEN - i);
 				/* Skip to end of path. */
 				while (ps[i + 1] != '\0')
 					i++;