Re: [PATCH] add set_shells_file function to getusershell module of gnulib

[Bruno Haible]

Hello Ben,

> I find that the getusershell module is limited in which file it can
> open (/etc/shells).  set_shells_file is a new function that allows the
> user to open a shells file that is located elsewhere.
> 
> I've attached the patch rather than providing it inline, because I
> didn't want to gamble with gmail's word-wrapping.

There are three problems with your patch:

  1) The 'getusershell' module is meant to be a substitute, for those
     platforms that don't have these functions. (See
     doc/glibc-functions/getusershell.texi.) This means, on glibc or
     Solaris systems, for example, gnulib's lib/getusershell.c is
     never compiled. What could/would you want to do so that the
     libc function getusershell() looks elsewhere than in /etc/shells?

  2) You create a new file "getusershell.h". But glibc has these functions
     declared in <unistd.h>, therefore gnulib declares them there as well
     (see lib/unistd.in.h). We don't want to have overlapping and possibly
     conflicting declarations in two different header files of gnulib.

  3) Your set_shells_file function stores a pointer to the passed string
     argument. It should make a copy instead. Otherwise code like

       {
         char buf[100];
         strcpy (buf, "/var/etc/shells");
         set_shells_file (buf);
       }

     will make the program crash later.

Bruno