 NEWS/Changelog for Rserve
---------------------------

NOTE: Rserve 1.8 series has many new features, but it has also removed
      support for control commands. If you absolutely need them,
      please use Rserve 1.7 series and notify me so I can assess
      whether they may be resurrected for the 1.9 series. If you don't
      know what it means, just ignore this note.

1.8-16	2025-12-15
    o	Adapt to API changes in R 4.6.0


1.8-15	2024-12-10
    o	The static HTTP/HTTPS handers are now officially supported
	so Rserve.http.add.static() is now exported and documented.
	Also Rserve.http.rm.all.statics() has been added to allow the
	removal of all handlers.

    o	There were several bugfixes in the handling of paths in the
	static http handlers (sanitization was done on the full path
	instead of the request part only and separating / are now
	inserted where necessary).

    o	Shorthand arguments --RS-simple-http <path> and
	--RS-simple-http-only <path> have been added to the command
	line Rserve. They disable QAP and register a static http
	handler using the supplied <path> as document root. If
	http.port has not been set, it will default to 8080.
	Note that the <path> should be absolute since Rserve changes
	the working directory to / when daemonizing (or use
	--RS-set daemon=no). The --RS-simple-http variant continues
	to process other handlers (static or R) while the
	--RS-simple-http-only variant will respond with 404 if
	the resource is not found (see Rserve.http.add.static()
	documentation).
	
	QAP can be re-enabled if desired by subsequent arguments. If
	the desire is to only run a HTTPS server then --RS-set http.port=0
	can be used to disable the default and then add all necessary
	arguments (or a config file) for the TLS part.

    o	added run.Rserve(background=TRUE) mode which meshes server
	processing loop (i.e., the loop which accepts new connections)
	and the R session event loop. The function returns as soon
	as all the server ports are bound (essentailly immediately).
	This allows the server R process to run R code in the main
	session after the server was started and thus influence future
	client connections. This is currently only supported on unix.

	Please note that any changes to the server R session only
	affect new connections, not existing ones.

	If a function .Rserve.served is defined in the global
	environment then it will be called after each new accepted
	client connection in the main R session.

	Function stop.Rserve() can be used to stop and remove all
	servers started with run.Rserve(). Note that all existing
	client connections will remain intact.

	NB: This functionality is currently considered experimental
	and the return value is undefined (currently TRUE on success,
	but may return other information in the future to enable more
	fine-grained control over the background servers).


1.8-14	2024-02-13
    o	Windows: use pkg-config if available (many thanks to Tomas
	Kalibera for the work on the toolchain!)

    o	Close listening socket when re-attaching session. (#155)

    o	Fixes to the sample C++ client.


1.8-13	2023-11-28
    o	replace sprintf with snprintf even in safe cases to avoid
	compiler warnings.


1.8-12	2023-08-17
    o	added a work-around for buggy libcrypt (first seen in Ubuntu
	22.04) which incorrectly uses salt leading to authentication
	error if crypt is used even with a correct password. (#192)

    o	parsing of dates in conditional requests could be off, leading
	to fewer 304 Not Modified responses than expected (proxy).

    o	added experimental built-in feature in Rserve's HTTP(s) server
	to serve static files directly (similar to the feature of the
	forward proxy). Multiple prefixes can be registered to serve
	static content from different paths using the
	Rserve:::Rserve.http.add.static() function. Static handlers
	are processed before R handers, but they can pass on requests
	if the file is not found. Conditional requests are supported.


1.8-11	2022-11-28
    o	fix possible buffer overflow attacks in WebSockets code (many
	thanks to Dane Henshall for performing a security audit!)

    o	clean up code to avoid mixing 32-bit and 64-bit integers on
	64-bit platforms

    o	enhance `Rserve.eval()` to report the condition object for
	error conditions in the `condition` component of the
	`Rserve-eval-error` object (#154) and to support custom 
	calling	handlers.

	This is done by adding a new argument `handlers` to
	`Rserve.eval()` which allows registration of calling handlers
	for the duration of the evaluation. The default
	is to register an `error` handler which stores the condition
	(via `Rserve_set_last_condition`) so `Rserve.eval` can pick
	it up and return in the `condition` component. To revert
	to previous behavior, use `handers=NULL` which prevents the
	registration of handlers.

    o	Issue a warning if eval/source configuration directive is used
	in `run.Rserve()` since they only affect stand-alone Rserve
	daemon startup and thus setting them in an R session is likely
	a mistake (as the user can run R code directly in the session
	prior to calling `run.Rserve()` instead).


1.8-10	2021-11-25
    o	reduce the size of the authkey (nonce) in CMD_reqKey to
	256 bytes such that the payload of CMD_secLogin can fit
	into one encryption block (for 4096-bit RSA key). This
	improves the nonce entropy size from 50 bytes to 256.
	Note that effectively the maximum safe size of the
	authentication payload is 206 bytes. Larger sizes can be
	transmitted, but should be considered unsafe due to
	the second block not including any nonce.

    o	Prevent replay attacks on non-forked servers using
	CMD_secLogin without CMD_keyReq. (Thanks to
	Dane Henshall for reporting!)
	Deployments relying on CMD_secLogin for authentication
	should upgrade to this version to avoid vulnerability.
	Note that clients do not have to be updated.

    o	Respect CPPFLAGS and LDFLAGS from R CMD config


1.8-9	2021-11-05
    o	move m4 under tools according to R-exts 1.2

    o	several fixes to QAP encoding/decoding, use R_xlen_t
	type for indexing if available (previously Windows
	builds used 32-bit index due to long int size limits).

    o	protection fixes for serialized commands

    o	remove rsio entirely since it is not used


1.8-8	2021-10-31
    o	add basic ulog logging for QAP1 even outside of OCAP mode (#169)

    o	TLS configuration options now check the success of the
	operation and will issue a warning if it failed. Most
	importantly `tls.key` must succeed in order for the
	server to support TLS.

    o	New option `tls.client` governs the treatment of client
	certificates. There are following possible values:

	none        - does not ask nor check the client certificate
	request     - request certificate from the client, but
		      do not check its validity
	require	    - require client certificate, if not present
		      or not valid, reject the connection
	match:...   - client's common name  must match exactly one
		      of the listed (comma-separated) names. No spaces
		      are allowed around the commas.
	prefix:...  - the client's common name must start with the
		      specified prefix
	suffix:...  - the client's common name must end with the
		      specified suffix

	The options `match`, `prefix` and `suffix` imply `require`.
	Each of them can be specified only once. However, it is
	possible to use up to one each in which case the requirement
	is treated as logical "or", e.g.,

	    tls.client match:foo.bar
	    tls.client suffix:me.com

	will allow both clients	`foo.bar` and `foo.me.com`.

	NOTE: `none`/`request`/`require` are mutually exclusive. If
	more than one is specified, the behavior is undefined
	(currently the last one wins but that shold not be relied
	upon). All comparisons are case-senstitive (sorry, no regex
	support at this point, because we do not want to depend on
	PCRE just yet).

	If the `tls.client` option is not specified, then the default
	behavior is one of `none` or `request`. In that case no attempt
	is made to control the TLS behavior so it depends on the SSL
	library's default whether it asks for the client certificate
	or not, but in either case it is not checked.

	NOTE: probably the best way to use the new feature is to use
	certificates issued by your organization with
	`tls.client require` and `tls.ca` set to the organization's CA
	certificate which means you don't need to check client names
	and yet no unauthorized client can connect.

    o	-DULOG_STDERR now correctly produces ulog output on stderr
	and ulog output is visible in the debug build

    o	TLS shutdowns are performed explicitly and sockets closed
	(only affects non-forking servers)

    o	several possible leaks of arguments under error conditions
	were fixed


1.8-7	2020-12-17
    o	proxy: fail with an error if no servers can bind (#152)

    o	proxy: fail if SSL cannot be initialized

    o	include err.h SSL header outside of debug mode


1.8-6	2020-06-11
    o	proxy: handle WebSockets control frames (PING/PONG/CLOSE)
	proper.

    o	proxy: fail with an error if key/certificate cannot be
	loaded at start time. Both -k and -c are required to
	enable TLS/SSL. Also the proxy will issues an error if -k
	is used and SSL support has not been available at compile
	time. (#127)

    o	proxy: linking no longer hard-codes `-lssl` (it effectively
	failed compilation when SSL was not available).

    o	proxy: added -S <host>[:<port>] which allows automatic
	registration and de-registation with a server manager
	when the service is available (e.g., this can be used
	to keep the compute node list up-to-date automatically
	when load-balancing via the nginx reverse proxy).

    o	support large vectors in QAP encoding/decoding

    o	restore some Windows compatibility - at least to the point
	where it compiles. It is still strongly discouraged to use
	Windows given how limited the OS is and how it prevents
	any sensible use (Windows only supports single-client,
	single-thread, cooperative mode - so for toy uses only).

    o	content-type header entry is lower-cased only up to a
	semicolon since trailing options may be case-sensitive. (#149)


1.8-5	2017-03-25
    o	add support for callback in OCAP idle mode. If the function
	.ocap.idle() exists in the global environment and the
	configuration option

	  use.idle.callback yes

	is set then that function is called inside each OCAP iteration
	after a timeout of 200ms (i.e., if R is idle in the OCAP loop
	with no input from any side for at least 200ms).

    o	control commands are now officially disabled since they never
	worked reliably in the 1.8 series after the the rsio re-write.


1.8-4	2015-12-23
    o	bugfix: when using compute separation on some Linux systems the
	death of the compute process may remain undetected. Rserve
	now actively detects if the compute process has terminated and
	will signal accordingly. The same goes of a compute process
	whose parent has died.

    o	bugfix: make sure headers are correctly terminated when using
	forward proxy and R scripts.

    o	bugfix: static files served by the proxy had duplicate (and
	possibly conflicting) content-type headers.


1.8-3	2015-07-20
    o	add support for the notion of a context object which can be
	retrieved/set using Rserve.context() function. If

	   io.use.context yes

	configuration option is set then the context is passed
	as-is in OOB console callbacks as the first argument after
	the callback name.

	Rserve.eval() can also safely set a context object for the
	duration of the evaluation which guarantees that any
	previous context is restored upon exit - both on error or
	success.

    o	added WebSockets/QAP proxy and HTTP server. It is a
	stand-alone program that can be used to separate the R process
	from the network to enhance security. typical setup is for the
	proxy to listen on an outside port and connect to Rserve on a
	local (unix) socket which is restricted to the user running
	the proxy.

	It is enabled by default and installed into the package's libs
	directory along with the Rserve binaries. It is, however, not
	installed into $R_HOME/bin. The building of the proxy can be
	disabled via --disable-proxy configure directive.


1.8-2	2015-05-20
    o	fix bug in the WebSockets protocol implementation where frames
	over 64kB from the client may be parsed incorrectly.


1.8-1	2015-04-08
    o	add ulog() R function to allow custom logging from R code

    o	add "fork here" directive which allows to spawn multiple
	pre-forked instances of Rserve which all share the same
	memory. The rest of the configuration file is then ignored in
	the forked instance while the parent server instance continues
	to read on. This can be useful on machines with many cores and
	very short requests where the serial fork() time for each
	connection is in the order of the computing time. Note that by
	design this only works in configuration files and cannot be
	used on the command line.

    o	daemonize only *after* all servers have been bound such the
	exit code can be used to detect if Rserve has actually
	started successfully

    o   add Rserve.eval() function to perfrom REPL-like evaluation

    o	add a new config option to close all stdio file descriptors
	(stdin, stdout, stderr) on daemonization:

	   close.all.stdio enable

	For compatibiliy the default is false.

    o	Rserve will honor --silent command line option (destined for R)
	to not print the "Rserve started .." line.

    o	add support for console input OOB message, enabled via

	    console.input enable

	When enabled R will request input to ReadConsole by sending a
	OOB message to the client, expecting back a string to be used
	as input to the console. It is only honored if console.oob is
	also enabled.


1.8-0	2014-09-03
    o	new logging mechanism has been added to Rserve. It can
	be enabled using the

	   ulog <path>

	directive and uses syslogd-compatible unix socket or UDP
	datagram transfer to log events. Currently, only OCAP
	events are logged.

    o	OCAPs can now be tagged with a name	

    o	avoid duplicate symbols by not loading the Rserve dylib
	inside an embedded Rserve instance. This avoid issues
	of calling the wrong symbols, but it implies that
	run.Rserve() can no longer be used from within a
	child proces of an embedded Rserve instance (which
	you really don't want to do anyway).

    o	symbols are now registered *before* processing source/eval
	directives from the configuration file

    o	added new option to remove the working directory on
	session close recursively - activated by

	   workdir.clean enable

	If not set, the default is to only remove it if it is empty
	(on the assumption there are files that will be served beyond
	the life of the session).

    o	added workdir.parent.mode option which specifies the
	permissions on the parent directory of session working
	directories. The default is 0755. Unlike workdir.mode this one
	does not respect the umask (beause it may be shared and thus
	may need to include permissions that are otherwise not
	granted).

    o	the data offset field in the QAP header is deprecated and can
	be used for message ID if enabled using

	   msg.id enable

	In that mode all responses will copy the message ID from the
	request and new requests (such as OOB send/msg) will use
	randomly generated message IDs. This allows clients to more
	easily track responses for nested commands. Note that this is
	backwards-compatible if old clients use the convention of 0
	data offset which was the norm (as long as OOB is not used).

    o	nested evaluation is supported in OCAP mode. This means that
	OCcall followed by another OCcall can be processed before the
	first call terminates if the R side issues an OOB message in
	which case the second OCcall will be nested within the first
	call.

    o	allow expansion of environment variables in the configuration
	file, i.e., ${VAR} will be replaced with the contents of the
	VAR environemnt variable. This only applies to the right-hand
	side of configuration directives.

    o	added command line argument --RS-set which allows any
	configuration directive that is accepted in the configuration
	file to be specified on the command line as
	--RS-set directive=value
 
    o	fix a typo in the "daemon" configuration option which was
	looking for "deamon" instead.

    o	added support for console callbacks. They can be enabled using

    	   console.oob enable

	directive and they result in OOB messages being sent on
	console I/O operations.

    o	add a configuration option "shutdown disable" that will
	disable the shutdown command. This makes is a bit harder
	for unprivileged users to shut down the Rserve instance.
	It does not disable the ctrlShutdown command, so users that
	have control command access can still issue a shutdown.
	Note that this option will eventually become the default
	so consider specifically using "shutdown enable" where
	CMD_shutdown is still needed.
	
	Note that the shutdown command is not functional in cases
	where user switching is performed anyway, so is it only used
	for backward compatibility. Only ctrlShutdown is guaranteed
	to work.

    o	add a configuration option "oob.idle.interval" which will
	trigger automated OOB send of "idle" command after a
	specified interval. Currently it only works with
	WebSockets.

    o	add a configuration option "forward.stdio enable" which
	will enable capturing of stdout/err and forward it to
	the peer via OOB send messages. Note that this requires
	thread support and uses additional file descriptors.
	It in currently only available in OCAP WebSockets.

    o	bugfix: pairlists were incorrecty protected when parsing
	SEXPs (qap_decode) in messages from client to server (#16).


1.7-3	2013-08-21
    o	the handling of server configuration modes has been
	inconsistent for some combinations (mostly affected were
	combinations involving WebSockets upgrade and OC mode on
	HTTP/WS servers). Also the websockets.qap.oc configuration
	option has been misspelled.

    o	HTTPS->WSS upgrade is now supported

    o	mkdist -i installs the built package, use -c for check

    o	Windows compatibility has been restored thanks to
	David Champagne from Revolution Analytics


1.7-2	2013-08-12
    o	when uid/gid is changed, create a new tempdir() and set its
	permissions as well as the wokring directory's owner to match.

    o	bugfix: if the first command is not any of the eval family
	the Rserve may respond with an additional, spurious error
	response

    o	deamonized server would record incorrect pid when pid.file
	is used (i#5). The pid is now removed on clean sutdown.

    o	added support for keep.alive configuration option - it is
	global to all servers and if enabled the client sockets are
	instructed to keep the connection alive by periodic messages.


1.7-1	2013-07-02
    o	remove a spurious character that prevented compilation on Suns

    o	add OPENSSL_INCLUDES precious variable that can be used to
	point to non-standard location of OpenSSL headers

    o	check the usability of OpenSSL headers before enabling TLS
	support

    o	added the choice of GPLv2 or GPLv2 with OpenSSL linking exception


1.7-0

   ***	---- HEADLINE NEWS ----
   ***	new protocols: HTTP, HTTPS, WebSockets and TLS/QAP
   ***	added protocol switching (from QAP to TLS/QAP) via CMD_switch
   ***	The R client was moved to RSclient package
   ***	New in-session server support with run.Rserve()
   ***	Out-of-band messages via self.oobSend()
   ***  user-based uid/gid switch, MD5/SHA1 stored passwords
   ***  preliminary IPv6 support; RSA secure authentication
   ***  .Rserve.done global env hook for optiopnal cleanup
   ***  auth.function setting to allow custom authentication
   ***  Object-capability mode for hardened, secure services
   ***	---- END - see below for details ----

    o	This is the first release in the new 1.x Rserve series. Many
	of the Rserve internals have been re-written or cleaned
	up. The original protocol remains the same (so all clients
	that worked with Rserve 0.6 will continue to work), but the
	suite of available protocols has been extended (see below).

    o	added support for multiple protocols in Rserve:

        ** QAP **
	this is the original Rserve protocol used in Rserve 0.x
	series. It works over TCP/IP and unix sockets. It is
	enabled by default and can be disabled using
	"qap disable" configuration directive.

	** HTTP **
	this is very similar to the built-in R http server except that
	on unix it forks on connection so it allows parallel separate,
	persistent connections. It requires a worker function
	.http.request to be defined in the session which will handle
	incoming requests. This allows the use of facilities like
	FastRWeb without an external webserver. This protocol is
	disabled by default and can be enabled by setting "http.port"
	configuration directive to the desired port to listen to.
	(Also see TLS support below for https server).

	The http.raw.body configuration option (default is false which
	results in the same behavior as Rhttpd) can be used to force
	passing body in raw form to the handler (useful for the
	FastRWeb handler which does its own parsing).

	** WebSockets **
	this protocol is used by HTML5 web browsers for direct access
	to R with a persistent connection. This allows implementation
	of websites that have a dedicated R session (and could be used
	as an R console). There are two subprotocols supported by
	Rserve:

	  -- WebSocket(*, "QAP") --
	  this is a tunnel for the original QAP protocol through
	  WebSockets. It requires a browser capable of binary
	  WebSockets protocol (version 01 or higher). It allows very
	  efficient data transfer, typically by loading ArrayBuffers
	  directly into GPU or CPU.
	  It is disabled by default and can be enabled using
	  "websockets.qap enable" configuration directive.
	  (If no subprotocol is specified, QAP is assumed)

	  -- WebSocket(*, "text") --
	  this is a very simplistic protocol using plain text frames
	  to send input to R and output from R directly as text. It
	  acts essentially as an R console. This protocol works with
	  any WebSockets implementation including version hybi-00 and
	  hixie-75/76
	  It is disabled by default and can be enabled using
	  "websockets.text enable" configuration directive.

	  NOTE: The textual WebSockets protocol does NOT provide any
	  authentication mechanism, so use with extreme care as you
	  are essentially giving any user with a web browser access to
	  R and thus to the shell.
	  
	In addition to enabling each or both subprotocols, the port on
	which the WebSockets server should listen must be specified in
	the configuration using "websockets.port" directive, for
	example "websockets.port 8080". Alternatively, the HTTP server
	can be enabled to allow connection upgrade to WebSockets on
	the same port with "http.upgrade.websockets enable"

	NOTE: remember that the default in Rserve is to disallow
	remote connections, so you may need to use "remote enable" in
	order to use WebSockets or HTTP in practice, since the point
	is to serve remote machines. Typically, if both QAP and either
	HTTP or WebSockets are used, it is recommended to use QAP on a
	local unix socket for better access control.

    o	Rserve now supports SSL/TLS connections on QAP, HTTP and WS
	protocols. The TLS key/CA entries are common for all
	protocols. The relevant new configuration directives are:

	  tls.key <private key PEM file>
	  tls.cert <server certificate PEM file>
	  tls.ca <CA PEM file issuing the above certificate>

	SSL/TLS can be used in several ways: with separate port for
	TLS connections or by switching protocol form a regular QAP
	connection using CMD_switch with "TLS" as argument. The latter
	can be enabled using

	  switch.qap.tls enable

	Enabled switching is advertized by Rserve with the presence
	of a "TLS" entry in the ID string. Keys and other TLS entries
	must be initialized in order for TLS to be enabled.

	Dedicated TLS servers can be enabled by specifying the port
	for the corresponding protocol:

 	  qap.tls.port <port>        - for Rserve/QAP
	  http.tls.port <port>       - for HTTPS
	  websockets.tls.port <port> - for WebSockets

	(there are synonyms "https.port" for "http.tls.port" and
	 "tls.port" for "qap.tls.port", however, the *.tls.port
	 versions are preferred for clarity)

	The use of TLS protocols is encouraged where sensitive data
	is transmitted or when requiring secure authentication. For
	QAP protocol, using TCL/QAP with SHA1 passwords (also new, see
	below) is the currently recommended way where authorization is
	required. The only drawback is increased CPU utilization
	during transfers casued by the encryption and the fact that
	TLS-enabled clients must be used. See also RSA secure
	authentication (CMD_keyReq + CMD_secLogin) for a different
	method if only the authentication step is to be encrypted.

	When enabling TLS tls.key and tls.cert are mandatory, tls.ca
	is optional to establish CA chain of trust (whether this is
	needed depends on the client and the certificate). To generate
	a key and self-signed certificate, you can use something like
	
	  openssl genrsa -out server.key 2048
	  openssl req -new -key server.key -out server.csr
	  openssl x509 -req -days 365 -in server.csr \
                  -signkey server.key -out server.crt

	NOTE: TLS services are started **in addition** to any other
	servers, i.e., if you want to enable TLS/QAP only, you have to
	set tls.qap.port but also add "qap disable" to disable the
	plain Rserve access.

    o	QAP servers (classic Rserve QAP, QAP/TLS and WebSocket/QAP)
	support object-capability (OC) mode in which all Rserve
	commands are disabled except for CMD_OCcall. All messages
	including the initial handshake are always QAP and the initial
	message defines capabilities (here opaque references to
	closures) that can be called. This mode can be enabled using

	  qap.oc enable            ## for Rserve QAP and QAP/TLS
	  websockets.qap.oc enable ## for WebSockets/QAP
	
	In this mode the configuration *must* define a function
	oc.init (typically using eval or source configuration
	directives) which has to supply OC references that can be used
	in calls. If the evaluation of oc.init() fails, the connection
	is closed immediately. The use of invalid OC references or any
	other commands other than CMD_OCcall results in immediate
	connection termination. This allows creation of hardened,
	secure services that can disallow arbitrary code execution.

	NOTE: this mode is inherenty incompatible with all classic
	Rserve clients. The first four bytes of the initial packet are
	"RsOC" instead of "Rsrv"

    o	Rserve can now be started from within an existing R session
	using run.Rserve() command. This allows the user to prepare a
	session "by hand", run Rserve from within that session and go
	back to the session (by shutting down the server or sending an
	interrupt). This allows the use of Rserve even without the
	presence of libR.

    o	Rserve now supports out-of-band (OOB) messages. Those can be
	sent using the self.oobSend() [one-way] and self.oobMessage()
	[roundtrip] functions from within code that is evaluated in
	Rserve child instances. OOB messages are not used by Rserve
	itself but offer asynchronous notification to clients that
	support it (one typical use are WS-QAP1 tunnels	to web
	browsers that allow status updates as R code is evaluated).

    o	Rserve accepts additional command line arguments:
	--RS-source <file>   (same as "source <file>" in cfg file)
	--RS-enable-remote   (same as "remote enable" in cfg file)
	--RS-enable-control  (same as "control enable" in cfg file)

    o	The Rserve package no longer includes the R client. It has
	been moved to a separate package "RSclient" so that it can be
	used on machines separate from the server.

    o	There was a bug in QAP storage estimation affecting pairlists,
	possibly resulting in buffer overflows. This should be fixed
	and an error message will be printed when such overflows are
	detected in the future (which hopefully won't happen).

    o	Bugfix: command line parsing would skip over some arguments

    o	Passwords file can contain MD5 or SHA1 hash of a password
	instead of the plaintext password for non-crypt
	authentication. In that case the hash must be lowercase	hex
	representation with preceding $ sign, so for example user
	"foo" with password "bar" would have an entry
	foo $62cdb7020ff920e5aa642c3d4066950dd1f01f4d
	You can use
	  echo -n 'password' | openssl sha1
  	to obtain the SHA1 hash of a password (openssl md5 for MD5
	hash - MD5 is probably more common but less secure than
	SHA1). This feature makes sure that passwords are not stored
	in plain text and thus are safe from local attacks.

    o	Rserve now has the ability to change uid/gid according to the
	user that has been authenticated. The following settings
	concern this feature (unix-only):

	   auto.uid {enable|disable} [disable]
	   auto.gid {enable}disable} [disable]
	   default.uid <uid> [none]
	   default.gid <gid> [none]

	The auto.uid/gid directives enable setuid/setgid based on
	user's uid/gid. In case no uid/gid is specified with the
	username, the default.uid/gid settings will be used. If there
	is no uid/gid in the username and no defaults are specified,
	the user's authentication will fail. User's uid/gid can be
	specified in the passwords file by appending /uid,gid to the
	username. If gid is not specified, uid will be used for both
	uid and gid. So for example user "foo" (from the above MD5
	example) with uid=501 would have an entry on the passwords
	file:

	   foo/501 $37b51d194a7513e45b56f6524f2d51f2

	For this to work, Rserve must be started as root. However,
	with auto.uid enabled it is safe to do so since Rserve will
	prevent any R access until authenticated. You should, however,
	use a client capable of secure RSA authentication or use secure
	connection such as QAP/TLS as to not send password in
	cleartext over the wire.

    o	Rserve can now be run in a mode where each connection has a
	different uid and/or gid such that separate client instances
	are isolated. This allows more restricted setup in cases where
	instances may not be trusted and need to be sandboxed. The
	following configuration directives are associated with this
	functionality:

	   random.uid {enable|disable} [disable]
	   random.gui {enable|disable} [disable]
	   random.uid.range {<from>..<to>} [32768..65540]

	If random.uid is enabled and random.gid disable then only the
	uid of the process is changed. If both are enabled then the
	gid is set to match the value of the uid. random.gid cannot be
	enabled without random.uid.

	To support sandboxing, the permissions on the working
	directory can be specified using

	   workdir.mode <mode>

    o	If any kind of client-process uid switching is enabled in the
	configuration, the permissions on the working directory will
	match the uid of the process. Also the working directories are
	now named by the process ID to facilitate cleanup.

    o	Rserve now supports secure authentication even outside of
	SSL/TLS. There are two new commands that can be used by the
	client:
	
	CMD_keyReq   - requests an authentication key from the server
	               that will be used to perform a secure
	               login. The kind of the requested key is
	               specified as a parameter. Currently, only
	               "rsa-authkey" is supported which returns server
	               authentication key (authkey) and a RSA public
	               key which must be used to encode the authkey
	               and the authentication information (see below).
		       The RSA key can be compared on the client side
	               to ensure the authenticity of the server.

	CMD_secLogin - secure login. It consists of an encrypted data
	               stream that will authenticate the user. In the
	               case of the "rsa-authkey" method, the stream
	               consists of the authkey and the login +
	               password, all of which must be encrypted using
	               server's RSA key.

	The RSA key on the server (Rserve) side is specified using

	   rsa.key <RSA private key file>

	configuration file directive. The file is expected to be in
	PEM format. You can generate such file, e.g., with:

	   openssl genrsa -out server.key 4096

	where 4096 is the key size in bits. A public key can be
	extracted from the private key using

	   openssl rsa -pubout -in server.key -out server_pub.key

	The clients can pre-share the public key by other means to
	compare it to the key received from the server as to verify
	its authenticity. This will prevent them from sending the
	authentication information to rogue servers.

	NOTE: if the rsa.key directive is missing, Rserve will
	generate a key on the fly when asked for RSA authentication -
	although this allows encrypted transmission and thus is safe
	from sniffing, it is not safe from man-in-the-middle attacks
	where a rogue server intercepts the request and sends its own
	public key. Therefore the use of the rsa.key directive is
	highly recommended.

	The RSA authentication enables the client to a) check the
	authenticity of the server (by comparing the RSA public key)
	and b) send authentication information encrypted. This method
	is highly recommended in cases where a full TLS/SSL encryption
	of the entire connection would be too expensive (i.e. in cases
	where the data is large and the security of the transported
	data is not crucial).

    o	Rserve has a preliminary IPv6 support. Rserve must be
    	installed with --enable-ipv6 configure flag to enable it in
	the Rserve build. In order to start all servers on IPv6 add

	   ipv6 enable

	to the configuration file. The option is global, i.e. once
	enabled it applies to all servers that support it. Note that
	not all features work with IPv6 yet - detaching sessions
	(they will use IPv4 for re-attach) and remote client filtering
	only work with IPv4 at this point.

    o	Rserve now binds only to the loopback interface in
	"remote disable" mode. This is safer and prevents remote DoS
	attacks. Previously, Rserve would bind on all interfaces and
	check the peer IP address. If desired, you can replicate the
	old behavior by adding

	   remote enable
	   allow 127.0.0.1

	to the configuration (if you don't know the difference then
	you don't need this -- if you actually need this, then you
	probably want to add more "allow" entries for the machine's
	other interfaces as well).

    o	If a function .Rserve.done() is defined in the global
	environment, it will be run after a clean connection
	shutdown. This allows custom code to be run when a client
	connection is closed.

    o	If a function .Rserve.served() is defined in the global
	environment of the server, it will be run after a client
	connection has been served. For forked servers this is just
	after the fork(), for co-operative servers this is after the
	client conenction has been closed. It is guaranteed that no
	other client is served before the call so it can be used to
	manage resources that are unsafe to share with forked
	processes (e.g. sockets etc.).

    o	The server and client process can be tagged with extra
	information in argv[0] so it is possible to distinguish the
	server and children. This behavior can be enabled using

	    tag.argv enable

	Note, however, that this not always possible and it will have
	impact on programs that use argv[0] such as killall.

    o	Added configuration option pid.file and command-line option
	--RS-pidfile which instructs Rserve to write its process id
	(pid) into that file at startup.

    o	Added configuration directives http.user, https.user and
	websockets.user which take a username and perform
	setuid/setgid/initgroups immediately after forking.
	This minimizes the amount of code that is run with
	elevated privileges in cases where user switching is desired.

    o	Added configuration directive

	   daemon disable

	which can be used to prevent Rserve from daemonizing. It has
	effect only in builds of Rserve that support daemonization.
	Note that -DNODAEMON build flag disables daemonization
	entirely and can be used in any Rserve version.

    o	All commands based on eval now also accept DT_SEXP in addition
	to DT_STRING. In such case the parse step is skipped and the
	expression is evaluated directly. The intended use of this
	functionality is to evaluate language constructs and thus
	allow calls with both reference and inlined arguments.

    o	QAP decoding is slightly more efficient and avoids protection
	cascades. QAP_decode() has now only one argument and it	is
	guaranteed to not increase the protection stack when returning
	(which implies that it is the responsibility of the caller to
	protect the result if needed).

    o	Both QAP encoding and decoding now use native copy operations
	on little-endian machines which can increase the speed
	considerably when the compiler cannot do this optimization
	on its own (most commoly used compilers don't).

    o	Assigning logical NAs now uses the proper NA_LOGICAL value
	that is also recognized by R. (PR#276)

    o	Forked child processes will now close all server sockets so
	that any server can be restarted without closing existing
	children.

    o	Signal handling has been streamlined: the server process
	captures HUP, TERM and INT which will lead to clean
	shutdown. Child processes restore signal handlers back to R so
	that regular R signal handling rules apply. Note that
	interrupt during eval will result in RESP_ERR with code 127
	even if try() is used.


--- In order to support new ideas a major re-organization of Rserve ---
--- has been started - almost 10 years after the first release.     ---
--- It is time to look ahead again with a new major version. The    ---
--- protocol will remain compatible so 1.x series can be used to    ---
--- replace the previous 0.x series                                 ---


0.6-8	2012-02-20
    o	added RSserverEval() and RSserverSource() control commands
	in the R client as well as ctrl parameter to RSshutdown().

    o	added new facility that allows R scripts running in Rserve to
	issue control commands if allowed. This feature must be
	enabled in the Rserve configuration file using

	r-control enable

	This will make self.ctrlEval() and self.ctrlSource() functions
	available to code that is running within the Rserve
	instance. It is also possible to use this feature without
	explicitly loading the Rserve package via
	.Call("Rserve_ctrlEval", paste(text, collapse='\n'))
	.Call("Rserve_ctrlSource", as.character(file))
	although this may change in the future.

0.6-7	2012-01-17
    o   fix processing of login information
    	**IMPORTANT**: this fixes a serious security hole in the 
	remote login mechanism! If you rely on authentication,
	please make sure you update your Rserve immediately!
	(Thanks to Daniel Faber for reporting)

    o	add a namespace to make R 2.14+ happy

    o	work around broken readBin() in R 2.14.0 that errors
	on unsigned integers (affects R client only)

0.6-6	2011-12-10
    o	fix a bug that can cause heap corruption due to incorrect
	addressing in padding of symbols. Unless extremely long symbol
	names are used it is unlikely to have a real effect in
	practice, but in theory it could be used to zero targetted
	parts of the heap. Thanks to Ralph Heinkel for reporting.

    o	fix Rserve() call on Windows with quote=FALSE and more than
	one argument.

    o	clarify that sisocks.h is under LGPL 2.1 as well as the other
	headers used by clients.

    o	add support for plain S4 objects (S4SEXP) in assignments
	(Note: derived S4 objects - those using other native SEXP type
	as a base - cannot be supported properly, becasue there is no
	way to distinguish them from S3 objects!)

    o	Unsupported types in CMD_assign will no longer crash R.
	The resulting object is always NULL and an error is printed on
	the R side.


0.6-5	2011-06-21
    o	use new install.libs.R custom installation script in R 2.13.1
	to install binaries

    o	install clients by default on Windows as well

    o	multi-arch binaries are no longer installed with the arch suffix
	in the package root. The canonical place is libs$(R_ARCH) instead.
	For now Rserve.exe/Rserve_d.exe are still installed in the root
	but they will be also removed in the future as they are not
	multi-arch safe.


0.6-4	2011-05-19
    o	make all buffers capable of using 64-bit sizes. This means
	that clients can use more that 4Gb of data on 64-bit platforms
	when communicating with Rserve, provided the buffer limits are
	either disabled or configured to be high enough. Note that this
	does not change	the limitations in R with respect to vector
	lengths so you still can only use up to 2^31-1 elements.
   
    o	bug fix: contrary to the documentation scalar logicals were sent
	in the old XT_BOOL format instead of XT_ARRAY_BOOL

    o	work around several issues introduced in R 2.13.0 for Windows

	Rserve() now also allows arguments to be passed to system() for
	more fine-grained control of the environment, mostly to work
	around bugs and incompatible changes to system() on Windows
	in R 2.13.0 (commonly used options are invisible=FALSE to get
	back to a more reasonable pre-2.13.0 behavior and wait=TRUE if
	using R 2.13.0 that has broken wait=FALSE support).

    o	In Rserve() startup wrapper, args are now quoted automatically
	if quote=TRUE is set. For backward compatilility args are not
	quoted by default if they consist of just one string.


0.6-3	2011-01-17
    o	bug fix: the child process could get stuck in the server loop
	after some abnormal return from the child connection code
	Thanks to David Richardson for reporting.

    o	set R_ARCH automatically on Windows if a multi-arch R is
	detected (such as CRAN binaries since R 2.12.0)

    o	add R_ARCH support in Rserve() on Windows to locate the
	proper binary

    o	bug fix: C++ client did not handle new-style lists (introduced
	in Rserve 0.5) properly. Thanks to Carl Martin Grewe for
	reporting.


0.6-2	2010-09-02
    o	add support for NAs in character vectors by using a special
	"\xff" string. Any string beginning with '\xff' is
	prepended by additional '\xff' to remove ambiuguity and clients
	should remove leading '\xff' accordingly.
	(Note that UTF-8 encoded strings never contain '\xff' so
	in most uses it never occurs).

	The Java client has been updated accordingly and represents
	NA strings with null.

    o	add a new config file option "interactive" that allows to run
	Rserve in interactive or non-interactive mode across platforms.
	Previously Windows ran in non-interactive mode and unix in
	interactive mode. Non-interactive mode is useful if you want
	to prevent R from soliciting user input, but it requires error
	option to be set if you don't want to quit R on all errors
	(i.e., something like options(error=function() NULL) will do)

	Note: on unix the interactivity flag can only be set *after* R
	initialization (due to limitation in R) so you still may have
	to pass flags like --no-save in order to appease R.

    o	more Windows fixes - Rserve uses R's own initialization in
	recent R versions. This also fixes issues with Win64 and more
	recent toolchains.
	Note that both Widnows and unix now behave consistently with
	respect to interactive mode - the default is now interactive
	for both platforms but can be changed in the config file.


0.6-1	2010-05-24
    o	add a safety margin to the send buffer to avoid crashes when
	size estimates are off (e.g., due to re-coding)

    o	added a very primitive PHP client

    o	Win64 fixes by Brian Ripley

    o	added new configuration options:
	su {now|server|client} - switches user either immediately
	as the config file is loaded ("now", default and always the
	behavior of Rserve before 0.6-1), when the server is ready
	("server") or when a client is spawned ("client"). The
	latter is useful to restrict clients from sending signals
	to the server process.

	uid, gid config options are interpreted accordingly to
	the su value.

	cachepwd - {no|yes|indefinitely} - allows Rserve to cache
	the password file. "no" = read it at each authorization
	(default and behavior before 0.6-1), "yes" = read it when
	a client is spawned before su, "indefinitely" = read it
	just after the config file (most efficient but changes
	are only active after re-start). "yes" has only effect
	in unix and can be used to restrict permissions on the
	password file such that client code has no access to it
	(do does "indefinitely" but can be used anywhere).


0.6-0	2009-10-27
    o	added support for control commands CMD_ctrlEval,
	CMD_ctrlSource and CMD_ctrlShutdown. Those commands provide
	control over the server process. The side-efect of eval and
	source are then available to all future connections.

	Control commands are only available if they are enabled, e.g.,
	with the config file entry "control enable". In addition if
	authorization is required or the passwords file is set only
	designated users will have control access (see next point).

	Note that enabling control commands will make Rserve use at
	least one file descriptor per active child process, so you may
	want to adjust the maximum number of file descriptor in your
	system if you expect hundreds of concurrent clients.

    o	The passwords file format has been enhanced to give
	finer-granularity control over the user authorization.

	Only users with "@" prefix can issue control commands. The
	prefix is not part of the user name for authentication
	purposes.

	In addition, if the password file contains an entry
	starting with "*" it will be interpreted as blank
	authorization, i.e. any username/pwd will authenticate. This
	may be useful in conjunction with control prefix, e.g., the
	following file would give blank authorization to all users but
	only the user "joe" will be able to use control commands:

	@joe foobar
	*

    o	Windows build cleanup (thanks to Brian Ripley)

    o	fixed decoding of XT_RAW (it advanced too far), this affected
	the use of XT_RAW as non-last element only (thanks to Saptarshi
	Guha for reporting)

    o	don't advertize ARuc if not supported (this bug only affected
	systems without crypt support with plaintext enabled and
	required authorization)

    o	add assign support for logical vectors


0.5-3	2009-01-25
    o	fix SET_VECTOR_ELT/SET_STRING_ELT mismatches

    o	set object flag when decoding objects that have
	a "class" attribute (fixes issues with S3 objects that
	were passed from the client to the server).

    o	set S4 bit for pure S4 objects (S4SEXP). No other S4
	objects are supported because there is no way to tell
	that an assembled object is really an S4 object

    o	added string encoding support (where R supports it)
	The string encoding can be set in the configuration file
	(directive "encoding"), on the command line with --RS-encoding
	or within a session by the client command CMD_setEncoding.

	This means that strings are converted to the given encoding
	before being sent to the client and also all strings from the
	client are assumed to come from the given encoding.
	(Previously the strings were always passed as-is with no
	conversion). The currently supported encodings are "native"
	(same as the server session locale), "utf8" and	"latin1". The
	server default is currently "native" for compatibility with
	previous versions (but may change to "utf8" in the future, so
	explicit use of encoding in the config file is advised).

	If a server is used mainly by Java clients, it is advisable to
	set the server encoding to "utf8" since that it the only
	encoding supported by Java clients.

	For efficieny it is still advisable to run Rserve in the same
	locale as the majority of clients to minimize the necessary
	conversions. With diverse clients UTF-8 is the most versatile
	encoding for the server to run in while it can still serve
	latin1 clients as well.


0.5-2	2008-10-17
    o	fix a bug in CMD_readFile and CMD_setBufferSize that
	resulted in invalid buffer sizes (one of the ways to
	trigger the bug was to attempt to read a small number of
	bytes with readFile). Thanks to H. Rehauer for reporting.

    o	ignore attributes if they are not in a LISTSXP - there seem
	to be other uses of the ATTRIB entry in conjunction with
	character hashes in recent R versions. (BR #76)

    o	adapt C++ client to changes in 0.5 (at least to the point
	where the demo1 code works)

    o	add support for XT_VECTOR_EXP in assignments

    o	improve protection for vectors

    o	report "remote" setting in --RS-settings

    o	updates in the REngine Java client, added documentation


0.5-1	2008-07-22
    o	fix build issue with R 2.7.x on Windows

    o	mergefat now works properly and uses cp if there is no lipo
	(this fixes multi-arch issues on Mac OS X and makes sure that
	Rserve/Rserve.dbg are installed even on non-Mac systems)


0.5-0	2008-07-21
    o	added CMD_serEval and CMD_serAssign which are highly efficient
	when talking to R clients as they don't need any intermediate
	buffer. The corresponding R client functions RSeval and
	RSassign have been re-written to use this new API.

    o	deprecate scalar types in the protocol

    o	add more efficient storage for dotted-pair lists
	and symbol names

    o	add support for complex numbers

    o	new Java client: REngine
	it is more flexible than JRclient and it can be used with
	other Java/R engines such as JRI. Also it has a much more
	clean API and better exeption handling.
	- allow NaNs to be passed in raw form to R, i.e. double
	  NAs can be created using
	  Double.longBitsToDouble(0x7ff00000000007a2L)
	  (nice methods for this should follow)

    o	C++ client was moved to src/client/cxx

JRclient:
    o	change the representation of lists to generic
	named vectors (class RList)

    o	change the ways attributes are accessed


0.4-7	2007-01-14
    o	relax DLL versions checking on Windows

    o	added more sophisticated implementation of RSassign
	in R client to support larger data. Nevertheless, due to
	limitations in R, objects must be serializable to
	less than 8MB to be assignable via RSassign.

    o	added more robust error handling in the R client

    o	fixed compilation on systems with custom include dir
	(such as Debian)

    o	JRclient is now part of the Rserve package.
	See clients.txt for details.
	It is not compiled by default (but installed when
	--with-client is specified), because we cannot assume the
	existence of a Java compiler.


0.4-6	2006-11-30
    o	fixed bug in RSeval when handling large objects

    o	minor fix in RSassign

    o	add an endianness hack for Windows in case config.h is not
	included properly


0.4-5	2006-11-29
    o	added --with-server option (by default enabled). When disabled,
	the server itself is not built. When enabled, R must provide R
	shared library, i.e. it must have been compiled with
	--enable-R-shlib.

    o	added --with-client option (by default disabled). When
	enabled, the C/C++ client is built and installed in the
	package. It will be copied in the "client" directory of the
	package and contains all files necessary for building a
	client application.

	This option has no effect on the R client which is always
	built and installed.

    o	Windows version of Rserve now builds and installs both debug
	(Rserve_d.exe) and regular (Rserve.exe) version of Rserve. In
	addition, the Rserve function can now be used to launch Rserve
	even on Windows.

    o	endianness detection now prefers information from the compiler
	macros thus allowing cross-compilation. Use -D_BIG_ENDIAN_ or
	-D_LITTLE_ENDIAN_ to override it if necessary.

    o	allows universal build on Mac OS X

    o	adapt to R_ParseVector interface change in R-devel


0.4-4	2006-11-15
    o	first release on CRAN

    o	added support for RAW type (both in and out)

    o	added rudimentary client support (thanks to David Reiss for
	his contributions) and documentation


Previous major releases:

0.4	2005-08-31
    *	added support for sessions

0.3	2003-10-07
    *	new format for boolean arrays
	last version: 0.3-18 (2005-08-28)

0.2	2003-08-21
    *	support for large objects

0.1 	2002-07-06
    *	first release
