/*
    userver -- (pronounced you-server or micro-server).
    This file is part of the userver, a high-performance 
    web server designed for performance experiments.
          
    Original Copyright (C) 2004 Hewlett Packard Company
    Copyright (C) 2005-2011  Tim Brecht

    Authors: Tim Brecht <brecht@cs.uwaterloo.ca>
    See AUTHORS file for list of contributors to the project.
  
    This program is free software; you can redistribute it and/or
    modify it under the terms of the GNU General Public License as
    published by the Free Software Foundation; either version 2 of the
    License, or (at your option) any later version.
  
    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    General Public License for more details.
  
    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
    02111-1307 USA
*/

userver-0.9.0
  o Released: Mon Dec 26 19:14:25 EST 2011
  o TBB - tried using indent to reformat all the code
  o TBB - this should be the result of the code cleanup, reorg and
          addition of code to handle range requests

userver-0.8.2
  o Not Released: continuing code reorg and support for range requests and 
    some portability

userver-0.8.1
  o Not Released: temporary version before doing some code cleanup
  o TBB - Adding support for range requests and reorganizing the code to 
    make this easier
  o TBB - Added Adam Gruttner's fixed to log dynamic requests to the log file
  o TBB - changed the way a failed open call is handled 
          (used to just return 404, which was misleading in many cases).
  o TBB - fixed a bug in interest_set.c in compact_poll_array 
  o TBB - adding Tyler Szepesi's #ifdef'd code to try to reduce memory footprint

userver-0.8.0
  o Released: Sun 30 Jan 2011 11:35:31 EST
  o TBB - Added --fake-writing option for the read/write path (little mod used
          for understanding performance)
  o TBB - Fixed a bug in the path that uses reads and writes (do_write_not_cached)
          the would result in peristent connections getting closed after the first request
  o TBB - Added file reading stats (tracking bytes read from files using "read")
  o TBB - Small mods so things will compile and run on MAC OS X Snow Leopard
  o TBB - Cleaning up passfd code, writing a recv_fd into fcgiapp.c so don't need 
          passfd.c and passfd.h 
  o TBB - Merging Gary's passfd code so it works with fcgi-2.4.0/libfcgi 
          and FCGI-0.67
  o TBB - Tyler Szepesi and I merged in and debugged Mark Groves SSL code.

userver-0.7.0
  o Released: Sat Sep  4 12:21:26 EDT 2010
  o TBB - Tried to fix up headers/copyright notices to better 
          reflect my understanding of how things are meant to be done.
  o TBB - Added support for php scripts.
  o TBB - Changed the way that cache warming is done. 
          There was one way is sendfile was being used and another
          if it wasn't. There is now only one way which seems to be
          doing what we want it to (at least on FreeBSD)
  o TBB - Added some options to change the way that cache warming is done
  o TBB - Added --call-stats option 
  o TBB - Added ability to correlate caller id information with the server through
          a new Client-Id: header.  Client-Id: X Y
          X = client number
          Y = call number/request number within the client
          We've modified httperf to pass this as a header.
  o TBB - Mods and Fixes for FreeBSD
  o TBB - Added some code (a hack) to madvise the OS that the victim file
          could be removed from the file cache
  o TBB - Added some code (a hack) to slow down a specified "victim".
  o TBB - Fixed up some of the testdyn targets so that
    there was enough time to start the appserver before
    trying to connect with the userver
  o TBB - Added --server-id option (from other local versions)
  o TBB - Fixed --extra-accepts option (wasn't working with multiple listeners)
  o TBB - Don't allow --ignore-fd-setsize with options that require it.
  o TBB - Trying to fix problems that EPOLLHUPs are causing (see #ifdef FIXHUP code)
  o TBB - fixed problem in fcgi.c, POSTs were not sending QUERY_STRING causing
          the appservers to crash on Solaris
  o TBB - mods for compiling with SUNPRO compiler and gcc on Solaris
  o TBB - fixing one of the FIXHUP problems (FIXHUP was FIXUP and
          code actually wasn't getting compiled or used).
          

userver-0.6.0
  o Released Mon Jun 11 16:30:59 EDT 2007
  o TBB - resized some info struct fields because they were too small
  o TBB - added support for a single completion queue for the AIO code
  o TBB - did some special data structure sizing/padding for better cache
          alignment on IA64
  o TBB - changed where warming the cache is done to fix a bug
          that ends up creating listener sockets with very larger fds
	  than was expected -- added code to also check for this
	  in the future (see MAX_LISTENERS).
  o TBB - minor mods to compile and run on CYGWIN again
  o TBB - Added changes from David Pariag to include a bigger list of
          prime numbers. These are used to size the cache table size
          to the next largest prime number.
  o TBB - Allow a limited number of entries in the cache table and to
          evict entries when there are not availble slots in the cache table.
  o TBB - changed code so that --select-timeout=-1 (or any negative value)
          will have select/poll/epoll/aio_wait wait indefinitely for
          an event to occur.
  o TBB - some modifications to process_aio_events.c to handle/count purged
          events better
  o TBB - tried to make it easier to use some of the 2.6 functionality
          on systems without libc support and with libc support
  o CAB - added --num-dyn-buffers-per-appserver to give a more practical way
          to specify the number of dynamic buffers
  o CAB - added --app-req-queue-size option to specify the size of the queue
          that each application uses to defer requests until a resource
	  (application server or buffer space) becomes available
  o TBB - added finite state machine diagrams (fig and eps) to the doc 
          directory of the CVS repository.
  o CAB - several improvements to alloc_aligned() and related code:
           - ALLOC_MMAP_FILE will get you a file-backed memory mapped region
           - ORing in ALLOC_MLOCK will mlock() the region
           - alloc_track[] slots can be reused once they are freed
           - new function free_alloced_track() exposes the alloc_track[] slot
           - new function free_alloced_all() frees everything in alloc_track[]
  o CAB - added --dyn-lock-pages option to mlock() the dynamic buffers
  o CAB - added sendfile support for dynamic content
  o CAB - added --cfg-filename option
  o CAB - added --start-app-server option to specify application server
          processes that userver is responsible for starting
  o TBB - changed the way that some of the epoll calls are done inside
          of TRACE calls.
  o TBB - added encryption functionality from Brian Lynn
  o TBB - added some encryption tests to the Makefile
  o TBB - made some changes to the epoll code to handle a couple of problems
             o -p # wasn't working correctly
	     o connections weren't getting turned on and off properly
	  *** NOTE: this has been fixed for the --epoll-good option only ****
  o TBB - added Amol Shukla's mods to get things working on MAC OS.
  o TBB - added support for cpu_set_t for sched_set/getaffinity
  o TBB - fixed a problem with printing out the URI properly when logging.
  o TBB - fixed minor problem with --extra-accepts
  o TBB - added AVOID_BUF_REUSE flag for odd sendfile behaviour ;-)
  o TBB - attempted fix for bug with caching on and no sendfile with files
          of size 0 (http://rocket:8080/test/issue1)
  o TBB - if using --cache-warm check to see if --caching-on has been set
  o TBB - added a few checks to ensure that the --reply-buffer-size
          is large enough to hold the reply header
  o TBB - readded code for cpu_set_t for cpu sched affinity for the server
  o TBB - added code for cpu_set_t for sched affinity for the app servers
  o TBB - tried out some new code for printing the cpu_set/cpu_mask to stdout
  o TBB - trying to get the userver to close connections to the appserver
          when it is shutting down
  o TBB - print a message when exit is called because of a problem rather
          than because it is being shutdown via a signal.

userver-0.5.1
  o Released Nov 29, 2004
  o CAB - reworked fastcgi buffering/copying code to remove extra copy.
  o TBB - changed the way --aio-completion-order is specified.
          Now uses a string of 'rwa' characters.
  o TBB - added some preposted and current connections to trace output for aio
  o CAB - now assemble FastCGI replies in dynamically-allocated buffers (from
	  a pre-allocated pool); characteristics of this pool are specified
	  using the new --dyn-buffer-size, --num-dyn-buffers, and
	  --num-dyn-buffers-per-app options
  o TBB - added --aio-dont-wait option to allow for simply busy looping
          until new events are available
  o TBB - added --skip-header command line option 
  o CAB - changes to compile with g++
  o TBB - a few changes after the g++ changes
  o TBB - added --aio-dont-close and --aio-initial-prepost-only options
  o TBB - got things up and running on FreeBSD 

userver-0.5.0
  o Released Oct 19, 2004
  o CAB - added FastCGI support; see fastcgi/NOTES for detailed description
  o CAB - added --app option to specify application servers (currently
	  FastCGI and SPECweb99 types are supported)
  o CAB - added stats for FastCGI
  o CAB - major rewrite of parse_bytes()
	  now parse headers; Cookie and Content-Length are recognized
	  currently (needed for FastCGI), but adding support for other
	  headers should be easy
	  now support POST requests and "simple" HTTP/1.0 GET requests
  o AS  - added handling of SPECweb99 requests (if MOD_SPECWEB99 is defined)
  o CAB - now determine server hostname at startup (needed for FastCGI)
	  added --hostname option to override determined hostname
  o CAB - now determine the IP address + port # of incoming connections
	  this is needed for FastCGI, and could also allow us to reject an
	  incoming connection or take other special actions post-accept
  o CAB - added support for "simple" HTTP requests of the form "GET uri"
	  these are treated as HTTP/1.0 requests, headers not allowed
  o CAB - added code to perform DNS lookups of hostnames
	  you can now specify a hostname anywhere an IP address is expected
	  (e.g. --ip-addr, --app)
  o CAB - updates to userver(1) man page
  o TBB - a few minor IA64 related mods (e.g., can't used MOD_SPECWEB99)
  o TBB - added permutesesslog contributed by Yoshio Turner
  o TBB - adding more code to handle errors in the aio case
  o TBB - added call to aio_reset_stats when clearing userver stats
  o TBB - removed one of the calls to print out memory registration stats 
          (was printed twice)
  o BKL - added code for warming the cache before doing new connections
  o TBB - added a few tests for the --cache-warm option.
  o TBB - added a way to easily add new completion event orderings and
          to specify on the command line which one to use
  o CAB - fixed a bug that could cause leaking of cache entries
  o TBB - fixed bug with tracing specified events
  o TBB - increased several limitations on sizes of cache entries, etc.

userver-0.4.7
  o Release Aug 17, 2004
  o TBB - now only print cache table info if caching is on
  o TBB - fixed issues with not handling --aio-accept-thold=0
	  properly
  o TBB - added ability to specify document root directory using
	  option --doc-root
  o TBB - fixed a problem with using --ignore-fd-setsize that
	  was causing ordinary sockets to appear as though they
	  were listening sockets
  o TBB - fixed problem with AIO state machine
	  it turns out that an accept completion can arrive while
	  in the state FSM_READ_ARRIVED_WHILE_WRITING
  o TBB - in aio_loop avoid closing idle connections
  o TBB - added stats to count replies to bad/unhandled requests of
	  various types
  o TBB - added call to print aio collected stats
  o CAB - now properly check for mmap() returning MAP_FAILED (not NULL)
  o CAB - check for overflows when calculating how much memory to
	  allocate in info_init()
  o TBB - fixes so that special escape url's work with AIO
  o TBB - fixed escape url's so they work when --doc-root is specified
  o TBB - needed to track more info for listeners so now use info_listen
          for all version and not just edge triggered epoll (added parent_sd)
	  to info field too.
  o TBB - AIO mods so that one listener doesn't prepost all available
          connections or thresholds. We now divide connections and
	  --aio-accept-thold by the number of listening sockets.
  o CAB - you can now specify an empty string for the pid filename
	  (--pid-filename=), and userver won't attempt to create a pid file
  o TBB - made stdout line buffered
  o TBB - made some changes to sock_special to account for trying
          to use fds that are larger than FD_SETSIZE and --ignore-fd-setsize

userver-0.4.6
  o Released June 20, 2004
  o TBB - fixes to compile on IA64 with EPOLL
  o TBB - fixed problems with epoll/epoll2 caused by move to new
	  info/connection data structures (check if epoll_ctlv works)
  o TBB - changed a couple of %d's to %zd for size_t printfs in trace.c
  o TBB - changed the way Not found, etc are handled.
	  created reply_status_fill and let it fill in the buffer
	  and be written properly by the rest of the system
	  (fixes problems with 1.0 vs 1.1 and AIO)
  o TBB - added info_map_valid function to use to see if
	  the connection has been closed (changed send_do_io)
  o TBB - changed print_time to work use info_map_valid
  o TBB - added more stats for epoll/epoll2/epoll_ctlv
  o TBB - changed Makefile.base to include more test scripts
  o TBB - added more tests to the Makefile (e.g., epoll/epoll2/epoll_ctlv)
  o TBB - check return value on aio_sock_init
  o TBB - added code for using epoll with edge triggering USE_EPOLL_ET
  o TBB - added code for handling read before write for AIO
  o TBB - modified parsing code to improve handling of methods
	  that are not implemented
  o TBB - added more information about AIO options to the man page.
  o TBB - added more information about AIO to the NOTES file.
  o CAB - removed the src/docs directory from the distribution; there is
	  now a utility called makedocs (source included) which creates and
	  populates the src/docs directory during the build process
  o CAB - fixed pid file bug (e.g. --pid-filename="%s" would crash us)
  o CAB - now delete pid file at exit
  o TBB - added support for SKIP_HEADER with AIO
  o TBB - changed the way EPOLL_CTL_DEL is done/used when using epoll_ctlv
	  (we no longer put them in the ctlv array but instead issue epoll_ctl
	   calls immediately)
  o TBB - changed the way AIO events and preposting are handled to be more
	  state machine driven
  o TBB - added --ignore-fd-setsize option which can be used when not using
	  select and/or SEND.

userver-0.4.5
  o Released May 5, 2004
  o TBB - minor changes to fix compile problems on CYGWIN
  o TBB - fixed a couple of off by one errors in new code for
	  mapping sds to info (was causing segfaults under some conditions)
  o TBB - did more work on timing out idle connections (needs more testing)
  o TBB - fixed problem with listening sockets for poll case
  o TBB - adding stuff for preposting aio reads before aio accepts
  o TBB - added code to do cleanup (gets called by installing with atexit)
  o TBB - changed the way repeat_accept works to avoid running over num_idle
  o TBB - changed the way cached header buffers are allocated
  o TBB - tried to do some alignment without much success
	  (see posix_memalign calls) - for some reason they fail
	  under some tests
  o TBB - added new aio test suite that allows us to use remove clients
  o TBB - added code to handle aio_sock_write and aio_sock_writev
	  returning 0 bytes (indicating that the client
	  connection has been closed)
  o TBB - fixed problem with HTTP/1.0 requests with aio
  o TBB - added code to allow memory alignment specification
  o TBB - fixing problem with new accept requests exceed --aio-accept-thold
  o TBB - added some of the new test scripts into the distribution
  o TBB - fixed problem with HTTP 1.0 requests and aio
	  Thanks to Brian Lynn for pointing out the problem
  o TBB - now try to have header specify correct HTTP version on reply
  o TBB - limit the number of bytes being returned on an error
	  in reply_status (used for errors)
	  Thanks to Michel Arboi for pointing out the problem and
	  Amol Shukla for the fix.
  o TBB - added new HTTP 1.0 tests to Makefile for AIO
  o TBB - fixed problem with when/where select_timeout gets set if using
	  stats_interval


userver-0.4.4
  o Released April 5, 2004
  o TBB - changed the order in which some of the initialization is done
  o TBB - changed how some of the signals are used (no longer use SIGUSR1
	  and no longer install a default handler for SIGALRM)
  o TBB - added a testaio target to the Makefile
  o TBB - added more debugging output for aio code
  o TBB - added more stats for aio
  o TBB - fixed the event mask used to call aio_wait
  o TBB - recompiled on CYWIN and did a few small changes to compile
  o TBB - fixed a major bug in the caching code.
	  The problem was that under certain circumstances files
	  that were in the cache _and_being_served_ could be ejected.
	  I've implemented reference counting and only evict files
	  with a reference count of zero.  If we are ever in
	  a situation where we can't find a file to evict with a reference
	  count of zero we print an appropriate message and exit.
	  The reason for crashing is that the cache is sized too small
	  and performance could really be hurt.
	  That is, you should resize the cache and rerun the experiment.
  o TBB - mods to write trace files for multiple processes to different files
	  now when -p # is used they get written to userver-#.trace
  o TBB - added code to permit setting cpu mask on Linux 2.6.x systems
	  (i.e., --use-cpu-mask option combined with sched_setaffinity)
  o TBB - added Louay Gammo's code to do aperture control with the SEND kernel
	  and added information about --auto-accept-aperture to man page
  o TBB - mods to use new version of epoll_ctlv we've created
  o TBB - modified how connection/info data structure is indexed
  o TBB - modified how lru data structure is indexed
  o TBB - small mod to how idle connections are timed out (still needs
	  some more work).

userver-0.4.3:
  o Released January 27, 2004
  o TBB - added stuff to try a new epoll_ctlv system call we're exploring
  o TBB - updates for 2.6.1 on IA64
  o TBB - changed aio code to use memory regions
  o TBB - added some code to aio_fake.c to fake some memory
	  region use and checks
  o TBB - small changes to the way poll is working because there may
	  be a bug/problem with 2.6.0 returning events that we haven't
	  expressed an interest in
  o TBB - added changes so that output from different processes (-p #)
	  will be written to different files (userver-#.log)
  o TBB - added support for aio_sock_writev and added code for testing
	  to aio_fake.c
  o TBB - fixed up printing of stats and trace files when using aio_fake.c

userver-0.4.2:
  o Released January 21, 2004
  o TBB - slight reorg to some of the makefiles and added comments
  o TBB - reworked the testsend target for testing the userver
	  with the SEND kernel
  o TBB - created interest_set_change routine in order to move towards
	  a more efficient implementation of epoll changed all
	  select/poll/epoll code to use this instead of fuctions
	  interest_set_add_readable/writable
	  interest_set_del_readable/writable
	  interest_set_done
  o TBB - added --use-epoll2 option
	  this is used to explore fewer calls to epoll_ctl at the
	  possible expense of more events that we are not interested
	  in from epoll_wait
	  (see the man page -- userver.1 userver.txt for details)
  o TBB - added functions to call _syscalls for epoll so that
	  they show up in gprof (called sys_epoll_ctl, sys_epoll_wait,
	  and sys_epoll_create)
  o TBB - added the number of open connections to the --stats-interval output
  o TBB - added FSM_LISTENING state and put listening sockets into this state
  o TBB - added more running stats and improved code for formatting that output
  o TBB - added and fixed up some of the stats for the aio code
  o TBB - added the ability to do running stats for socket aio

userver-0.4.1:
  o Released December 30, 2003
  o TBB - reordered the CHANGELOG so it goes from most recent to
	  oldest versions
  o TBB - fixed some SEND kernel related code to work with multiple listeners
  o TBB - modifying a few things for epoll to work with the 2.6.0 kernel
	  (this still needs a bit of work as it may be a bit inefficient)
  o TBB - adding some simple running performance stats (to be expanded later)
	  this is enabled by using --stats-interval=N where N is the
	  interval between stats in seconds

userver-0.4.0:
  o Released November 18, 2003
  o TBB - incremented the sub version number because this version
	  reflects some pretty major changes
  o TBB - changed the way that versioning is done in the Makefile
  o TBB - added info to the man page about specifying IP address and port
	  as in --ip-addr 127.0.0.1:6806
  o TBB - minor mods so things will compile again on CYGWIN
  o TBB - fairly major reworkings so that we can support an
	  asynchronous I/O model.
  o TBB - added a check to the close_idle_conns function to try to ensure that
	  it doesn't close down any listening sockets.
	  The SEND and AIO interfaces may not provide information about which
	  listening socket (i.e., the one we call accept on) a new connection
	  comes from (i.e., the parent) so we may not be able to call
	  lru_acess on that socket - which could make it stale and a candidate
	  to be closed. Another possible solution would be to call lru_access
	  at the time an accept call is made (whether successful or not).
  o TBB - implemented a simple fake aio layer that helps to do a bit of
	  debugging of the aio_layer code and to provide a bit of an
	  example of how the layer is used and what the underlying
	  implementations need to provide.
  o TBB - trying to restructure to make it easier to support other
	  non http servers and to support dynamic requests
  o TBB - setting better defaults for the maximum connections and
	  the maximum fds
  o TBB - info.req.read_buf has been added and --read_buffer-size option
	  this was needed for AIO and could be useful for other
	  types of services
  o TBB - changed info.rep.file_buf to info.rep.reply_buf
	  and added --reply-buffer-size option
  o TBB - reorganizing to try to permit filling of reply_buf
	  and then having the rest of the code just drain it.
  o TBB - changed he way the parsing of requests is done to be more
	  compliant with the protocol
  o TBB - made some changes to give slightly better default options
	  (e.g., enable --use-sendfile and --use-tcp-cork if they are available)
	  Caching is also now turned on (but the cache table size, cache
	  size etc. will still need to be adjusted)
  o TBB - changed the way versioning gets done (versions are now controlled in
	  Makefile.base)
  o TBB - changed some of the default behaviour for --use-socket-aio
	  (i.e., caching is on and should use mmapped caching)
  o TBB - added code to register and deregister memory for socket aio.

userver-0.3.3:
  o Released October 9, 2003
  o TBB - adding code to allow server to listen on multiple interfaces/sockets
	  NOTE!: this isn't quite working yet with the SEND kernel code
  o TBB - added some simple regression testing to Makefile
	  (see test*: targets in the Makefile)
	  NOTE: requires httperf
  o TBB - added include directory to the distribution to show examples
	  of how to compile with larger FD_SETSIZE
  o TBB - changed the way the --version flag works
	  (thanks to Ian Wienand <ianw@gelato.unsw.edu.au>) for pointing
	  out the problem.
  o TBB - added some code to support "special" sockets, i.e., those that
	  should not be treated like regular client connections.
	  These might be back end processors like another server, an external
	  CGI or PHP process, etc.

userver-0.3.2:
  o Released October 3, 2003
  o TBB - cleaned up select_loop, poll_loop, epoll_loop, send_loop
	  to use more common code.
  o TBB - added some of the test scripts and httperf log file generator
	  code to the distribution
  o TBB - cleaned up, commented and added usage for the scripts
	  in the scripts directory
  o TBB - updated the README in the scripts directory
  o TBB - fixed incorrect closing of connections for special escape uri's
  o DP  - Added some code to optimize transfer of zero-byte file.
  o DP  - Added some code to trace accept, read, write, close, and
	  reply rates at the server side (uses special escape uri's)
  o TBB - Used inet_pton instead of inet_aton on Solaris
  o TBB - Added docs (test files) directory to the distribution

userver-0.3.1:
  o Released August 25, 2003
  o TBB - Modified some comparisons of sd (socket descriptor) with FD_SETSIZE
  o TBB - Added new option, --version to print version of the server
  o TBB - Print ifconfig info on Linux
	  (for experimental config info e.g., txqueuelen)
  o TBB - Print /proc/cpuinfo on Linux
	  (for experimental config info)
  o TBB - Added stats for ListenOverflows and ListenDrops from
	  /proc/net/netstat
  o TBB - Fixed glitch in getting args for --full-read
  o TBB - Use full path now for ifconfig
  o TBB - Added code to track replies per cache entry

userver-0.3.0:
  o Released August 1, 2003