Fix building of libfilezilla-0.34.0 on OpenBSD

[Bjorn Ketelaars]

r10380 (user impersonation), breaks compatibility with OpenBSD. OpenBSD does not support shadow(3) and crypt(3) causing building to fail.

As a workaround introduce FZ_OPENBSD, which is similar in behavior as FZ_MAC.

[Tim Kosse]

Thank you for the patch. Unfortunately the chosen approach is not feasible, adding a major operating system family disambiguation like this will result in long-term maintenance overhead.

It should be possible to fix this issue without any change to the library API:

• Add configure checks for crypt, shadow and any OpenBSD-specific replacement functions
• In lib/impersonation.cpp use the appropriate functions depending oon the HAVE_... #defines

Could you please update your patch accordingly?

[Bjorn Ketelaars]

New patch (libfilezilla.2.patch). This time configure checks for specific functions, and sets FZ_IMPERSONATION. The latter is used in demos/Makefile.am, lib/impersonation.cpp and lib/process.cpp.

[Tim Kosse]

I had a closer look at OpenBSD. Unfortunately impersonation cannot currently be implemented due to a lack of a thread-safe getpwnam_shadow_r, non-_r functions like getpwnam_shadow are completely unsafe to use in any code that uses libraries or is itself part of a library.

Fixing OpenBSD should be fairly easy though, just add this to ​src/lib/libc/gen/getpwent.c, update the headers and manpages in the process (Alternatively, but probably much more involved, would be to make all non-_r functions use thread-local storage):

int
getshadow_r(const char *name, struct passwd *pw, char *buf, size_t buflen,
   struct passwd **pwretp)
{
	return getpwnam_internal(name, pw, buf, buflen, pwretp, true, true);
}
DEF_WEAK(getshadow_r);

Can you please bring this to the attention of the relevant developers?

Leaving this bug open until the missing trivial functionality has been added to OpenBSD.