--- Urlader/README	2012/01/08 09:12:52	1.3
+++ Urlader/README	2012/06/17 13:11:25	1.5
@@ -182,17 +182,17 @@
         immediately if it can't.
 
         If successful it returns a lock object - the lock will be given up
-        when the lock object is destroyed.
+        when the lock object is destroyed or when the process exits (even on
+        a crash) and has a good chance of working on network drives as well.
 
         If the lock could not be acquired, "undef" is returned.
 
-        This function will probably go awway in the future, but is provided
-        to assist applications that want to clean up old versions, see "TIPS
-        AND TRICKS", below.
+        This function is provided to assist applications that want to clean
+        up old versions, see "TIPS AND TRICKS", below.
 
 TIPS AND TRICKS
     Gathering files
-        Gathering all the files needed for distribution cna be a big
+        Gathering all the files needed for distribution can be a big
         problem. Right now, Urlader does not assist you in this task in any
         way, however, just like perl source stripping, it is planned to
         unbundle the relevant technology from staticperl
@@ -262,6 +262,54 @@
         <http://cvs.schmorp.de/deliantra/Deliantra-Client/util/>, but
         looking at them can lead to premature blindless.
 
+    Shared Libraries
+        It is often desirable to package shared libraries - for example the
+        Deliantra client packages SD>, Berkely DB, Pango and amny other
+        libraries that are unlikely to be available on the target system.
+
+        This usually requires some fiddling (see below), and additionally
+        some environment variables to be set.
+
+        For example, on ELF systems you usually want LD_LIBRARY_PATH=. and
+        on OS X, you want DYLD_LIBRARY_PATH=. (these are effectively the
+        default on windows).
+
+        These can most easily be specified when building the packfile:
+
+           urlader-util ... LD_LIBRARY_PATH=. ./perl run
+
+    Portability: RPATH
+        Often perl is linked against a shared libperl.so - and might be so
+        using an rpath. Perl extensikns likewise might use an rpath, which
+        means the binary will mostly ignore LD_LIBRARY_PATH, which leads to
+        trouble.
+
+        There is an utility called chrpath, whose -d option can remove the
+        rpath from binaries, shared library and shared objects.
+
+    Portability: OS X DLL HELL
+        OS X has the most severe form of DLL hell I have seen - if you link
+        against system libraries, which is practically unavoidable, you get
+        libraries of well-known names (e.g. libjpeg) that have nothing to do
+        with what you normally expect libjpeg to be, and there is no way to
+        get your version of libjpeg into your program.
+
+        Moreover, even if apple ships well-known libraries (e.g. libiconv),
+        they often ship patched versions which have a different ABI or even
+        API then the real releases.
+
+        The only way aorund this I found was to change all library names in
+        my releases (libjpeg.dylib becomes libdeliantra-jpeg.dylin and so
+        on), by patching the paths in the share dlibraries and shared
+        objects. install-name-tool (with -id and -change) works in many
+        cases, but often paths are embedded indirectly, so you might have to
+        use a *dirty* string replacement.
+
+SECURITY CONSIDERATIONS
+    The urlader executable itself does not support setuig/setgid operation,
+    or running with elevated privileges - it does no input sanitisation, and
+    is trivially exploitable.
+
 AUTHOR
      Marc Lehmann <schmorp@schmorp.de>
      http://home.schmorp.de/