lineedit: get PWD from ash

The line editing code and ash disagree when the current directory
is changed to a symbolic link:

   ~ $ mkdir real
   ~ $ ln -s real link
   ~ $ cd link
   ~/real $ pwd
   /home/rmyf36/link

Note the prompt says we're in ~/real.  Bash does:

   [rmy@random ~]$ cd link
   [rmy@random link]$ pwd
   /home/rmyf36/link

Ash uses the name supplied by the user while the line editing code
calls getcwd(3).  The discrepancy can be avoided by fetching the
value of PWD from ash.

Hush calls getcwd(3) when the directory is changed
so there's no disagreement with the line editing code.

There is no standard how shells should handle cd'ing into
symlinks.

function                                             old     new   delta
parse_and_put_prompt                                 838     869     +31

Signed-off-by: Ron Yorston <rmy@pobox.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/libbb/lineedit.c b/libbb/lineedit.c
index b685399f9..697f2a577 100644
--- a/libbb/lineedit.c
+++ b/libbb/lineedit.c
@@ -2035,7 +2035,13 @@ static void parse_and_put_prompt(const char *prmt_ptr)
                                 case 'W': /* basename of cur dir */
                                         if (!cwd_buf) {
                                                 const char *home;
+#if ENABLE_SHELL_ASH
+                                                cwd_buf = state->sh_get_var
+                                                        ? xstrdup(state->sh_get_var("PWD"))
+                                                        : xrealloc_getcwd_or_warn(NULL);
+#else
                                                 cwd_buf = xrealloc_getcwd_or_warn(NULL);
+#endif
                                                 if (!cwd_buf)
                                                         cwd_buf = (char *)bb_msg_unknown;
                                                 else if ((home = get_homedir_or_NULL()) != NULL && home[0]) {