* ChangeLog :
 *
 * 2002/10/18 : 1.1.17
 *   - add the notion of "backup" servers, which are used only when all other
 *     servers are down.
 *   - make Set-Cookie return "" instead of "(null)" when the server has no
 *     cookie assigned (useful for backup servers).
 *   - "log" now supports an optionnal level name (info, notice, err ...) above
 *     which nothing is sent.
 *   - replaced some strncmp() with memcmp() for better efficiency.
 *   - added "capture cookie" option which logs client and/or server cookies
 *   - cleaned up/down messages and dump servers states upon SIGHUP
 *   - added a redirection feature for errors : "errorloc <errnum> <url>"
 *   - now we won't insist on connecting to a dead server, even with a cookie,
 *     unless option "persist" is specified.
 *   - added HTTP/408 response for client request time-out and HTTP/50[234] for
 *     server reply time-out or errors.
 * 2002/09/01 : 1.1.16
 *   - implement HTTP health checks when option "httpchk" is specified.
 * 2002/08/07 : 1.1.15
 *   - replaced setpgid()/setpgrp() with setsid() for better portability, because
 *     setpgrp() doesn't have the same meaning under Solaris, Linux, and OpenBSD.
 * 2002/07/20 : 1.1.14
 *   - added "postonly" cookie mode
 * 2002/07/15 : 1.1.13
 *   - tv_diff used inverted parameters which led to negative times !
 * 2002/07/13 : 1.1.12
 *   - fixed stats monitoring, and optimized some tv_* for most common cases.
 *   - replaced temporary 'newhdr' with 'trash' to reduce stack size
 *   - made HTTP errors more HTML-fiendly.
 *   - renamed strlcpy() to strlcpy2() because of a slightly difference between
 *     their behaviour (return value), to avoid confusion.
 *   - restricted HTTP messages to HTTP proxies only
 *   - added a 502 message when the connection has been refused by the server,
 *     to prevent clients from believing this is a zero-byte HTTP 0.9 reply.
 *   - changed 'Cache-control:' from 'no-cache="set-cookie"' to 'private' when
 *     inserting a cookie, because some caches (apache) don't understand it.
 *   - fixed processing of server headers when client is in SHUTR state
 * 2002/07/04 :
 *   - automatically close fd's 0,1 and 2 when going daemon ; setpgrp() after
 *     setpgid()
 * 2002/06/04 : 1.1.11
 *   - fixed multi-cookie handling in client request to allow clean deletion
 *     in insert+indirect mode. Now, only the server cookie is deleted and not
 *     all the header. Should now be compliant to RFC2109.
 *   - added a "nocache" option to "cookie" to specify that we explicitly want
 *     to add a "cache-control" header when we add a cookie.
 *     It is also possible to add an "Expires: <old-date>" to keep compatibility
 *     with old/broken caches.
 * 2002/05/10 : 1.1.10
 *   - if a cookie is used in insert+indirect mode, it's desirable that the
 *     the servers don't see it. It was not possible to remove it correctly
 *     with regexps, so now it's removed automatically.
 * 2002/04/19 : 1.1.9
 *   - don't use snprintf()'s return value as an end of message since it may
 *     be larger. This caused bus errors and segfaults in internal libc's
 *     getenv() during localtime() in send_log().
 *   - removed dead insecure send_syslog() function and all references to it.
 *   - fixed warnings on Solaris due to buggy implementation of isXXXX().
 * 2002/04/18 : 1.1.8
 *   - option "dontlognull"
 *   - fixed "double space" bug in config parser
 *   - fixed an uninitialized server field in case of dispatch
 *     with no existing server which could cause a segfault during
 *     logging.
 *   - the pid logged was always the father's, which was wrong for daemons.
 *   - fixed wrong level "LOG_INFO" for message "proxy started".
 * 2002/04/13 :
 *   - http logging is now complete :
 *     - ip:port, date, proxy, server
 *     - req_time, conn_time, hdr_time, tot_time
 *     - status, size, request
 *   - source address
 * 2002/04/12 : 1.1.7
 *   - added option forwardfor
 *   - added reqirep, reqidel, reqiallow, reqideny, rspirep, rspidel
 *   - added "log global" in "listen" section.
 * 2002/04/09 :
 *   - added a new "global" section :
 *     - logs
 *     - debug, quiet, daemon modes
 *     - uid, gid, chroot, nbproc, maxconn
 * 2002/04/08 : 1.1.6
 *   - regex are now chained and not limited anymore.
 *   - unavailable server now returns HTTP/502.
 *   - increased per-line args limit to 40
 *   - added reqallow/reqdeny to block some request on matches
 *   - added HTTP 400/403 responses
 * 2002/04/03 : 1.1.5
 *   - connection logging displayed incorrect source address.
 *   - added proxy start/stop and server up/down log events.
 *   - replaced log message short buffers with larger trash.
 *   - enlarged buffer to 8 kB and replace buffer to 4 kB.
 * 2002/03/25 : 1.1.4
 *   - made rise/fall/interval time configurable
 * 2002/03/22 : 1.1.3
 *   - fixed a bug : cr_expire and cw_expire were inverted in CL_STSHUT[WR]
 *     which could lead to loops.
 * 2002/03/21 : 1.1.2
 *   - fixed a bug in buffer management where we could have a loop
 *     between event_read() and process_{cli|srv} if R==BUFSIZE-MAXREWRITE.
 *     => implemented an adjustable buffer limit.
 *   - fixed a bug : expiration of tasks in wait queue timeout is used again,
 *     and running tasks are skipped.
 *   - added some debug lines for accept events.
 *   - send warnings for servers up/down.
 * 2002/03/12 : 1.1.1
 *   - fixed a bug in total failure handling
 *   - fixed a bug in timestamp comparison within same second (tv_cmp_ms)
 * 2002/03/10 : 1.1.0
 *   - fixed a few timeout bugs
 *   - rearranged the task scheduler subsystem to improve performance,
 *     add new tasks, and make it easier to later port to librt ;
 *   - allow multiple accept() for one select() wake up ;
 *   - implemented internal load balancing with basic health-check ;
 *   - cookie insertion and header add/replace/delete, with better strings
 *     support.
 * 2002/03/08
 *   - reworked buffer handling to fix a few rewrite bugs, and
 *     improve overall performance.
 *   - implement the "purge" option to delete server cookies in direct mode.
 * 2002/03/07
 *   - fixed some error cases where the maxfd was not decreased.
 * 2002/02/26
 *   - now supports transparent proxying, at least on linux 2.4.
 * 2002/02/12
 *   - soft stop works again (fixed select timeout computation).
 *   - it seems that TCP proxies sometimes cannot timeout.
 *   - added a "quiet" mode.
 *   - enforce file descriptor limitation on socket() and accept().
 * 2001/12/30 : release of version 1.0.2 : fixed a bug in header processing
 * 2001/12/19 : release of version 1.0.1 : no MSG_NOSIGNAL on solaris
 * 2001/12/16 : release of version 1.0.0.
 * 2001/12/16 : added syslog capability for each accepted connection.
 * 2001/11/19 : corrected premature end of files and occasional SIGPIPE.
 * 2001/10/31 : added health-check type servers (mode health) which replies OK then closes.
 * 2001/10/30 : added the ability to support standard TCP proxies and HTTP proxies
 * 		with or without cookies (use keyword http for this).
 * 2001/09/01 : added client/server header replacing with regexps.
 * 		eg:
 *			cliexp ^(Host:\ [^:]*).* Host:\ \1:80
 *			srvexp ^Server:\ .* Server:\ Apache
 * 2000/11/29 : first fully working release with complete FSMs and timeouts.
 * 2000/11/28 : major rewrite
 * 2000/11/26 : first write
