Bug#542430: Incorrect wildcard expansion when p_sh has arguments to the shell

[Bram Moolenaar]

James -

> The code in src/os_unix.c:mch_expand_wildcards which detects what shell
> is being used doesn't work properly if 'shell' has been set to a shell
> and arguments (e.g., "/bin/tcsh -f").
> 
> 5354     else if ((len = STRLEN(p_sh)) >= 3)
> 5355     {
> 5356         if (STRCMP(p_sh + len - 3, "csh") == 0)
> 5357             shell_style = STYLE_GLOB;
> 5358         else if (STRCMP(p_sh + len - 3, "zsh") == 0)
> 5359             shell_style = STYLE_PRINT;
> 5360     }
> 5361     if (shell_style == STYLE_ECHO && strstr((char *)gettail(p_sh),
> 5362
> "sh") != NULL)
> 5363         shell_style = STYLE_VIMGLOB;
> 
> Vim checks whether the last 3 characters of 'shell' are "csh".  Since
> the last 3 characters of p_sh in this case are " -f", Vim then checks
> whether "sh" is in gettail(p_sh) and uses sh-compatible shell expansion.
> 
> It looks like a safer approach would be to grab p_sh up to the first
> whitespace and then use gettail() on that to get the shell name.  That
> should reduce the false-positive rate for setting STYLE_VIMGLOB in line
> 5363.
> 
> Although, it'll still fail with shells like fish which will pass the
> strstr(..., "sh") check but not work with STYLE_VIMGLOB.  fish does work
> with STYLE_ECHO, so we could add that to the special-case list.

Well, theoretically there could be a space in the path.  I think
searching for the last slash, using gettail(), can comparing from that
position should work in most cases.  To catch "tcsh" as well as "csh" we
can use "strstr" on gettail().  That only fails for "sh -csh", but
that's unlikely to be used :-).

-- 
Any sufficiently advanced technology is indistinguishable from magic.
					Arthur C. Clarke
Any sufficiently advanced bug is indistinguishable from a feature.
                                        Rich Kulawiec

 /// Bram Moolenaar -- Bram at Moolenaar.net -- http://www.Moolenaar.net   \\\
///        sponsor Vim, vote for features -- http://www.Vim.org/sponsor/ \\\
\\\        download, build and distribute -- http://www.A-A-P.org        ///
 \\\            help me help AIDS victims -- http://ICCF-Holland.org    ///