This introduces a new way of linking Serval executables and dynamic
libraries from static libraries like libservald.a -- called
"feature-driven" linking.
The Makefile now links servald and serval-tests from libservald.a,
rather than from an explicit list of object (.o) files. Thanks to the
section-based method for registering functions such as HTTP handlers,
CLI commands and MDP handlers, these object files had become
"stand-alone" and hence were no longer included in the link because
there was no unresolved reference that required them to be linked in.
The new "feature.h" provides the DECLARE_FEATURE(name) macro that each
stand-alone source file uses to declare the named feature(s) it
provides. Each executable can call the USE_FEATURE(name) macro in any
of its explicitly-linked source files to cause the corresponding
object(s) to be included in the link, eg, servald_features.c.
The DEFINE_BINDING() macro has been extended so that every individual
MDP binding is given a feature name based on its port number macro, eg,
"mdp_binding_MDP_PORT_ECHO".
Some features have been factored into their own separate source files so
they can be omitted or included in a build independently of each other:
- the MDP bindings for MDP_PORT_DNALOOKUP, MDP_PORT_ECHO,
MDP_PORT_TRACE, MDP_PORT_KEYMAPREQUEST, MDP_PORT_RHIZOME_xxx,
MDP_PORT_PROBE, MDP_PORT_STUN, MDP_PORT_STUNREQ
- the CLI "log" and "echo" commands
- the CLI "rhizome direct" command
The JNI source files are only compiled if the <jni.h> header is present,
otherwise they are omitted from libservald.so.
The CLI and server main loop now have no conditional JNI code. All JNI
code has been moved into separate source files, which #include the new
"jni_common.h" instead of <jni.h>. The "cli.h" header no longer
includes <jni.h>, so the rest of the Serval source code is now
unaffected by JNI definitions.
The 'cf_limbo' global variable is now thread-local, so that each thread
has its own independent copy of the loaded configuration. The JNI
server entry point now calls cf_init() once. The new 'cf_initialised'
flag prevents clobbering the config state by redundant calls to
cf_init().
The CLI "stop" command now sends SIGHUP to the specific thread in which
the server is running. This is achieved by writing the PID and TID
(Linux Thread ID) into the pidfile, separated by a space, on systems
that support the Linux gettid() and tgkill() system calls. The server's
signal handler has been overhauled, and its logging improved.
