6dd4b07138eb8f479cc4205036c9d6a1794a9f80
galt
  Mon Nov 15 13:30:07 2021 -0800
Add domain exceptions whitelist for allowing us to configure a small number of exceptions that are old servers that are still incompatible with openssl. hg.conf setting httpsCertCheckDomainExceptions or env var https_cert_check_domain_exceptions. This setting is not intended to be used for new servers which should just be advised on correct openssl compatibility, which usually means getting their server to output their intermediate certs as well, or even the cert chain which is typically just 3 certs. refs #28458

diff --git src/product/mirrorManual.txt src/product/mirrorManual.txt
index 121d8b6..f8dd4d1 100644
--- src/product/mirrorManual.txt
+++ src/product/mirrorManual.txt
@@ -1,1803 +1,1806 @@
 [comment]: <> (QA: When you are done editing this file, cd into mirrorDocs, run 'make' there and follow the instructions)
 
 % Manual installation of the UCSC Genome Browser on a Unix server
 
 # Overview of the Genome Browser directories and databases
 
 The genome browser requires only Apache and MariaDB and uses these directories:
 
 - static html files: we typically keep them under /usr/local/apache/htdocs and
   configure Apache to load them from there, to avoid conflicts with the 
   distribution of the Linux default location /var/www/html
 - MariaDB databases: most of them are read-only, except the `hgcentral` database
   which is read-write. Most linux distributions keep these under /var/lib/mysql.
   (It is possible to get the genome browser to work with MySQL after version 8,
   but we do highly discourage it, as our download procedures use MyISAM .frm
   files which MySQL 8 dropped.)
 - static genome data files in /gbdb/
 - binary CGI programs that generate images from the MariaDB and /gbdb files and
   write them into the `trash` directory (see below). We modify our Apache
   config to load CGIs from /usr/local/apache/cgi-bin, so as to not conflict
   with the default directory of the Linux distribution
 - a directory for temp files called `trash`, located in the parent directory of the
   CGI programs, usually /usr/local/apache/trash
 - a small text file hg.conf in the same directory as the CGI programs, with
   information on how to connect to MariaDB, the location of the other directories
   and various other settings, on our machines the location of this file is
   /usr/local/apache/cgi-bin/hg.conf
 - uploaded custom data gets written by the CGI programs into MariaDB databases in
   the database `customtrash` and also into files under /usr/local/apache/trash
   which is symlinked from /usr/local/apache/htdocs/trash so these files are
   accessible to Apache.
 
 When a web browser requests a Genome Browser page, typically /cgi-bin/hgTracks,
 Apache executes this CGI program. The programs then read information about how to 
 connect to MariaDB using the file hg.conf, connects to MariaDB, reads the
 installed genome assemblies and the current user session from the MariaDB database
 hgcentral. For each genome assembly, there is a separate MariaDB database (e.g. 
 hg38). Some types of data (e.g. raw genome sequences) are kept as indexed
 binary files outside of MariaDB, they are located in /gbdb, e.g. /gbdb/hg38. The
 location of the /gbdb directory can be changed with a setting in hg.conf. Some
 types of data are not specific for a genome, these are kept in the MariaDB
 databases hgFixed, proteome and visiGene.
 
 We strongly recommend to follow the default locations, and to place our CGI
 programs in `/usr/local/apache/cgi-bin`.  The htdocs root directory for html
 files should then be in /usr/local/apache/htdocs.  All Genome Browser
 components called from Apache get their settings from the central configuration
 file `/usr/local/apache/cgi-bin/hg.conf`.  Among others, the location and the
 username/password for the MariaDB server is specified there.
 
 To load data into the genome browser databases, you need a command line tool
 like hgLoadBed.  These tools are distributed separately from the CGI programs.
 Some tools create only MariaDB tables, others write into a /gbdb subdirectory.
 Most of them require a configuration file ~/.hg.conf in your home directory
 with the MariaDB connection information, like server name, username and password.
 The data loading is done from the Unix command line and not dependent on the
 CGI programs that create the Genome Browser graphics.
 
 # Software Requirements
 
 To run our provided binaries:
 
 * Linux/Ubuntu/CentOS/Unix/MacOSX operating system
 * Apache2.x - http web server - <http://httpd.apache.org/>
 * MariaDB development system and libraries - <http://mariadb.com/>
   (MySQL 8 removed support for MyISAM schema files, which makes downloading
    our data file very cumbersome and slow)
 * libpng runtime and development packages - <http://www.libpng.org/>
 * libssl runtime and development packages - <http://www.openssl.org/>
 * Universally Unique Identifier library - <http://e2fsprogs.sourceforge.net/>
 
 If you want to make modifications to our software, you need to compile it:
 
 * gnu gcc - C code development system - <http://www.gnu.org/software/gcc/>
 * gnu make - <http://www.gnu.org/software/make/>
 
 Optional:
 
 * 'ghostscript' ps to pdf converter - <http://ghostscript.com>
 * 'git' source code management: <http://git-scm.com/downloads>
 * 'gmt' map plotting tools <http://www.soest.hawaii.edu/gmt/>
 * 'pstack' for stack traces
 * 'R' for the GTex track
 * 'python-mysqldb' for the gene interactions track (python2)
 
 It is best to install these packages with your standard operating
 system package management tools:
 
 * Debian/Ubuntu: `apt-get install ghostscript apache2 mariadb-server gmt r-base uuid-dev python-mysqldb`
 * Redhat/Fedora/CentOS: `yum install libpng12 httpd ghostscript GMT hdf5 R libuuid-devel MySQL-python`
 
 On newer distributions, python-mysqldb / MySQL-python is not available anymore.
 In this case, install python2, pip for it and then use pip to install the mysql
 library ("pip2 install MySQL-python").  See the file
 installer/browserSetup.sh for the commands.
 
 # Hardware and disk space requirements
 
 We currently use the following hardware to support our website:
 
 * 24 CPUs and 128Gb of memory for each of the six machines
 * 16 CPUs, 64 Gb of memory for the MariaDB server
 
 The UCSC Genome Browser website experiences over one million hits per
 day. Your hardware requirements may be much less demanding and will
 depend upon how much traffic you expect for your mirror.
 
 Annotation database size differs a lot between the assemblies: The full size
 of the hg19 database in 2016 is 6 TB, for ce2 it is 5GB. It also depends on
 the tracks: The size of the hg19 annotations can be reduced to 2TB if you
 do not download any ENCODE tracks. The size of only the main gene and SNP
 annotations is around 5GB for hg19 and hg38.
 
 You can use the following command to get the size of the files for all
 of the assemblies, but it can also be modified to give the size for a
 particular assembly:
 
     rsync -hna --stats rsync://hgdownload.soe.ucsc.edu/gbdb/ | egrep "Number of files:|total size is"
 
 For example, to get the size of all of the files for hg19, you would
 use the following command:
 
     rsync -hna --stats rsync://hgdownload.soe.ucsc.edu/gbdb/hg19/ | egrep "Number of files:|total size is"
 
 After running that command, you should see output like this:
 
     Number of files: 54886
     total size is 6515.70G  speedup is 5181080.38 (DRY RUN)
 
 The next command will give you the size of the entire mySQL/MariaDB database,
 but can be changed to get the size for a particular assembly:
   
     rsync -hna --stats rsync://hgdownload.soe.ucsc.edu/mysql/ | egrep "Number of files:|total size is"
 
 # Installing the UCSC Genome browser
 
 Note: we offer Genome-Browser-in-a-Box (GBIB), a fully configured virtual
 machine image that can be converted for VirtualBox, VMWare, Hyper-V and other
 popular environments.  We also offer Genome-Browser-in-the-Cloud (GBIC) an
 shell script that installs a genome browser in most main Linux distributions
 (Most Debian and Redhat-based ones, like Ubuntu and CentOS). 
 See https://genome.ucsc.edu/goldenPath/help/mirror.html
 
 Scripts to perform all of the functions below can be found in
 the directory https://github.com/ucscGenomeBrowser/kent/tree/master/src/product/scripts.
 In a git clone of the kent repository, the scripts
 are located in src/product/scripts.
 
 Confirm the following:
 
 1. Apache web server is installed and working, http://localhost/ 
     provides the Apache default home page from your machine
     NOTE: The browser static html web pages require the Apache
     XBitHack option to be enabled to allow SSI <!--#include ... --> statements to function.
     Add 'Options +Includes' for your html directory, your
     httpd.conf file entry looks like:
 
         XBitHack on
         <Directory /usr/local/apache/htdocs>
         Options +Includes
         </Directory>
  
     You can test your Apache cgi-bin/ directory by copying the script src/product/scripts/printEnv.pl into it.
 
 2. MariaDB database is installed and working
 
        mysql -u browser -pgenome -e 'show tables;' mysql
 
     MariaDB can be run from the command line, and
     the tables from the database MariaDB can be displayed.
 
     MariaDB development package is installed (mariadb-devel on RedHat)
     The directory: /usr/include/mysql/ has the mysql .h files
     And the library: /usr/lib/mysql/libmysqlclient.a exists
     (your exact pathnames may vary depending upon your installation)
 
     Set MySQL/MariaDB database access permissions.  The examples mentioned
     in the "Mysql setup" section will allow this
     setup to function as described here.
 
     To setup the example user accounts as mentioned in these
     instructions, run the script:
 
 	ex.MySQLUserPerms.sh
 
 3.  Find the location of your Apache WEB server DocumentRoot and cgi-bin directory.
     Typical locations are:  /var/www and /usr/local/apache, /var/www/html, /var/www/cgi-bin
     The directory where these are located is referred to as WEBROOT in this documentation:
 
         WEBROOT=/var/www
         export WEBROOT
 
     The browser WEB pages and cgi-bin binaries expect these
     two directories to be next to each other in ${WEBROOT}
     since referrals in html are often: "../cgi-bin"
     
     The browser should function even if WEBROOT is in a different
     directory from the primary Apache web root.  In this case,
     the three directories: html cgi-bin and trash should be
     at the same level in this other WEBROOT.  For example:
 
             /some/other/directory/path/html/
             /some/other/directory/path/cgi-bin/
             /some/other/directory/path/trash/
 
     Symlinks to the trash directory should exist from the html
     directory.  As so:
 
             /some/other/directory/path/html/trash -> ../trash
 
     The actual trash directory can be somewhere else.  If it is
     not in your Apache /var/www/trash/ directory, then create
     that symlink as well as the html/trash symlink.  For example
     /var/www/trash -> /some/other/directory/trash
     /var/www/html/trash -> /some/other/directory/trash
 
 4.  Create html, cgi-bin and trash directories:
 
         mkdir ${WEBROOT}/html
         mkdir ${WEBROOT}/cgi-bin
         chmod 755 ${WEBROOT}/cgi-bin
 
     (this chmod 755 will prevent suexec failures that are indicated
         by "Premature end of script headers" errors in the Apache
         error_log.  Your cgi binaries should also be 755 permissions.)
     
         mkdir ${WEBROOT}/trash
         chmod 777 ${WEBROOT}/trash
         ln -s ${WEBROOT}/trash  ${WEBROOT}/html/trash
         
     The browser creates .png (and other) files in the trash directory.
     The 'chmod 777' allows the Apache WEB server to write into
     that directory.
     
     A cron job should be set to periodically clean the files in trash.
     See also, the two scripts here: src/product/scripts/trashCleanMonitor.csh
             src/product/scripts/trashCleaner.csh
 
 5.  Download static WEB page content:
 	See also: src/product/scripts/updateHtml.sh
 
 6.  Copy CGI binaries: This set of binaries are for x86_64 types of Linux machines.
     If you need to instead build binaries for your platform,
     follow the instructions in the section "Building the kent source tree", below.
 
     See also: src/product/scripts/kentSrcUpdate.sh
 
         rsync -avP rsync://hgdownload.soe.ucsc.edu/cgi-bin/ ${WEBROOT}/cgi-bin/
 
 7.  Create hgcentral database and tables.  This is the primary gateway
     database that allows the browser to find specific organism
     databases.  See also: scripts/fetchHgCentral.sh to fetch
     a current copy of hgcentral.sql
     
         mysql -u browser -pgenome -e "create database hgcentral;"
         mysql -u browser -pgenome hgcentral < hgcentral.sql
     
     Please note, it is possible to create alternative hgcentral
     databases.  For example, for test purposes.  In this
     case use a unique name for the hgcentral database, such
     as "hgcentraltest", and it can be specified in the hg.conf
     file as mentioned in the next step.  To create a second copy
     of the hgcentral database:
     
         mysql -u browser -pgenome -e "create database hgcentraltest;"
         mysql -u browser -pgenome hgcentraltest < hgcentral.sql
 
 8.  Create the hg.conf file in ${WEBROOT}/cgi-bin/hg.conf
     to allow the CGI binaries to find the hgcentral database
 
     Use the file here: ex.hg.conf
     as the beginning template for your system:
 
     Copy the sample hg.conf:
 
         cp ex.hg.conf ${WEBROOT}/cgi-bin/hg.conf
 
     Please edit this hg.conf file and set any parameters required
     for your installation.  Use the comments in that file as your guide.
 
     Browser developers will want a copy of this file in
     their home directory with mode 600 and named: ~/.hg.conf
 
     These copies may have different db.user specification
     to allow developers write access to the database.
 
 10.  Load databases of interest.  See also: 
 
          src/product/scripts/activeDbList.sh
          src/product/scripts/minimal.db.list.txt
          src/product/scripts/loadDb.sh
 
      And discussion in scripts/README about whether you can use directly
      the MariaDB binary database files, or if you need to download goldenPath
      database text dumps and load them into the database. If you use MariaDB,
      you can use the binary files, with MySQL >= 8 you need to use dumps,
      which is why we discourage the use of MySQL >= 8 with the Genome Browser.
      
      An alternative to loading the database tables from text files,
      is to directly rsync the MariaDB tables themselves and place them
      in your MariaDB /var/ directory.  These tables are much larger
      than the text files due to the sizes of indexes created during a
      table load, but it can save a lot of time since the data loading
      step is quite compute intensive.  A typical rsync command for an
      entire database (e.g. ce4) would be something like:
 
         rsync -avP --delete --max-delete=20 rsync://hgdownload.soe.ucsc.edu/mysql/ce4/ /var/lib/mysql/ce4/
 
 11.  Download extra databases to work with a full genome assembly
     such as human/hg38: hgFixed go140213 proteins140122 sp140122
     Construct symlinks in your MariaDB data directory to use database
     names: go proteome uniProt for these database directories:
 
          $ ls -og proteome go uniProt
          lrwxrwxrwx 1  8 Feb 26 11:39 go -> go140213
          lrwxrwxrwx 1 14 Mar 27 12:01 proteome -> proteins140122
          lrwxrwxrwx 1  8 Mar 27 12:01 uniProt -> sp140122
  
          $ ls -ld go140213 proteins140122 sp140122
          drwx------ 2 mysql mysql 4096 Feb 26 10:57 go140213
          drwx------ 2 mysql mysql 4096 Aug 19 08:08 proteins140122
          drwx------ 2 mysql mysql 4096 Mar 26 13:01 sp140122
 
      These file names are data stamped YYMMDD to indicate changes
      over time as they are updated with new builds of the UCSC gene track.
      When a new UCSC gene track is released, fetch new databases and
      change the symlink.
 
 12.  Copy the gbdb data to /gbdb - See also:
 		scripts/fetchFullGbdb.sh
 		scripts/fetchMinimalGbdb.sh
 
 13.  The browser should now appear at the URL:
 	http://localhost/
 
      Check your Apache error_log file for hints to solving problems.
 
 14.  BLAT server setup: The blatServers table in the database hgcentral needs to
 	have a fully qualified host name specified in the 'host' column.
 
      Educational and non-profit institutions are allowed to use
      blat free of charge.  Commercial installations of the browser
      require a license for blat.  See also: <http://kentinformatics.com/index.html>
      and: <http://genome.ucsc.edu/license/>
      In the source tree: src/gfServer/README.blat
 
 15.  Useful links:
 
      <http://genomewiki.ucsc.edu/index.php/Category:Mirror_Site_FAQ>
  
      There are numerous README files in the source tree on
      a variety of specific subjects, e.g.:
  
          ./src/README
          ./src/product/README.*
          ./src/hg/makeDb/trackDB/README
          ./src/hg/makeDb/doc/make*.txt
 
 16. Apache configuration:
 
     To lock down your trash directory from scanning via "indexes"
     enter the following in your httpd.conf:
 
         <Directory "/var/www/html/trash">
         Options MultiViews
         AllowOverride None
         Order allow,deny
         Allow from all
         </Directory>
 
     The specified directory name is your apache: DocumentRoot/trash
     e.g. /usr/local/apache/htdocs/trash
 
 # MariaDB Setup
 
 1. Enable "LOAD DATA LOCAL INFILE":
 
     Set these in /etc/my.cnf or /etc/mysql/my.cnf:
 
         [mysqld]
         local-infile=1
 
         [client]
         local-infile=1
 
 2. MariaDB Storage Engine:
 
     In recent versions of MySQL/MariaDB, the default storage engine has changed from
     myisam to innodb.
     However the myisam engine should be used with the UCSC Genome Browser.
     
     Set it in /etc/my.cnf or /etc/mysql/my.cnf:
     
         [mysqld]
         default-storage-engine=MYISAM
 
     Always restart your MariaDB server after making changes to these
     configuration files.
 
 3. Users: There are three cases of identity to consider when providing
     access to the MariaDB system for the browser CGI binaries
     and browser developers:
 
     1.  A MariaDB user that needs read-only access to the
             genome databases.  The browser CGI binaries
             require read-only access to the genome databases.
     2.  A MariaDB user that has write permissions to one database.
             The CGI binaries require write permissions to one particular
             database (hgcentral) for maintaining user's cart information to
             store the user's browser cookie settings.
     3.  A MariaDB user that has general write permissions to all
             browser and genome databases to be used by developers
 
     The cgi-bin binaries obtain the first two of these MariaDB identities from
     the text file: $WEBROOT/cgi-bin/hg.conf
 
     Developers of the browser databases obtain their MariaDB identities
     from a text file in their home directory: ~/.hg.conf
     Note the initial dot in the name: .hg.conf
     This file in a user's directory will specify a higher-privileged user
     to allow read/write access to the MariaDB databases.
     This file must be set to mode 600 to provide security of the user
     and password to the database:
 
         $ chmod 600 ~/.hg.conf
 
     All kent source code commands use this file to access the MariaDB
     databases.  Since this file contains password information it
     requires the permissions to be set at 600 to keep it secret.
     The kent source code commands will enforce this access and not
     function unless it is set at 600 permissions.
 
     Therefore you will want to create three different MariaDB users
     for these purposes.
 
     The examples listed below are implemented in the shell script: src/product/scripts/ex.MySQLUserPerms.sh
     You can execute that script to set up these example users.
 
     An example full read/write access user: "browser",  is created with
     the following procedure.
 
     For the following it is assumed that your root account
     has access to the MariaDB database.  You should be able
     to perform the following:
 
         $ export SQL_PASSWORD=mysql_root_password
         $ mysql -u root -p${SQL_PASSWORD} -e "show tables;" mysql
 
     Create a MariaDB user called "browser" with password
     "genome" and give access to selected MariaDB commands
     for the following list of databases.  When you add other
     databases, you will need to add these permissions to your
     databases.  This procedure of adding permissions specifically
     for a set list of databases is a more secure method than allowing
     the MariaDB "browser" user to have access to any database.
 
     ( MySQL version 5.5 requires the LOCK TABLES permission here )
     ( FILE, CREATE, DROP, ALTER, LOCK TABLES, CREATE TEMPORARY TABLES on ${DB}.* )
 
         for DB in cb1 hgcentral hgFixed hg38 proteins140122 sp140122 go140213 uniProt go proteome
         do
             mysql -u root -p${SQL_PASSWORD} -e "GRANT SELECT, INSERT, UPDATE, DELETE, \
             FILE, CREATE, DROP, ALTER, CREATE TEMPORARY TABLES on ${DB}.* \
             TO browser@localhost \
             IDENTIFIED BY 'genome';" mysql
         done
 
     The above granted permissions are recommended for browser developers.
     The WEB browser CGI binaries need SELECT, INSERT and CREATE TEMPORARY
     TABLES permissions.  For example, you should create a special user for
     the browser genome databases only.  In this example, user: "readonly"
     with password: "access"
 
         for DB in cb1 hgcentral hgFixed hg38 proteins140122 sp140122 go140213 uniProt go
          proteome
         do
             mysql -u root -p${SQL_PASSWORD} -e "GRANT SELECT \
                 on ${DB}.* TO \
                 readonly@localhost IDENTIFIED BY 'access';" mysql
         done
 
     Create a database to hold temporary tables:
 
         mysql -u root -p${SQL_PASSWORD} -e "create database hgTemp"
 
         mysql -u root -p${SQL_PASSWORD} -e "GRANT SELECT, INSERT, \
             CREATE TEMPORARY TABLES \
             on hgTemp.* TO \
             readonly@localhost IDENTIFIED BY 'access';" mysql
 
     A third MariaDB user should be created with read-write access to only
     the hgcentral database.  For example, a user: "readwrite"
     with password: "update"
 
         for DB in hgcentral
         do
             mysql -u root -p${SQL_PASSWORD} -e "GRANT SELECT, INSERT, UPDATE, DELETE, \
                 CREATE, DROP, ALTER on ${DB}.* TO readwrite@localhost \
                 IDENTIFIED BY 'update';" mysql
         done
 
     The cgi-bin binaries obtain their MariaDB identities from
     the hg.conf file in the cgi-bin directory.  The file in this
     directory: src/product/ex.hg.conf
     demonstrates the use of the "readonly" user for genome database
     access and the "readwrite" user for hgcentral database access.
 
 4. The hgsql command: Developers can access the browser databases via the 'hgsql'
 command which can be built in the source-tree at:
 
 	kent/src/hg/hgsql/
 
     This 'hgsql' command provides a convenient front-end to
     the standard 'mysql' command by reading the user's ~/.hg.conf
     file to provide access to the browser databases with the
     appropriate identity.  Each user creates a ~/.hg.conf file
     (same format as the above mentioned cgi-bin/hg.conf file)
     and the specified database user identity is used for accesses
     to the browser databases.
 
     This same function of reading ~/.hg.conf for database access
     is built into all the source-tree binaries which modify the genome
     databases.
 
     The above example hg.conf could be used as a user's ~/.hg.conf
     file with the change of db.user, db.password, central.user,
     and central.password to be the fully permitted read-write user:
 
         db.user=browser
         db.password=genome
         central.user=browser
         central.password=genome
         central.db=hgcentral
 
     To test this access with your ~/.hg.conf file in place:
 
         hgsql -e "show tables;" hgcentral
         hgsql -e "show grants;" hgcentral
 
 
 5. Configuring MariaDB SSL connections (entirely optional, only needed if your IT department requires it):
 
     MariaDB is typically compiled with SSL capability from OpenSSL or yaSSL.
     To see if your server supports ssl, login to MariaDB and run this command:
 
         mysql> show variables like '%ssl%';
         +---------------+----------+
         | Variable_name | Value    |
         +---------------+----------+
         | have_openssl  | DISABLED |
         | have_ssl      | DISABLED |
         | ssl_ca        |          |
         | ssl_capath    |          |
         | ssl_cert      |          |
         | ssl_cipher    |          |
         | ssl_crl       |          |
         | ssl_crlpath   |          |
         | ssl_key       |          |
         +---------------+----------+
 
     If your MariaDB was compiled with SSL support, which is true of virtually all MariaDB packages
     being provided today, you can easily enable SSL by adding settings to /etc/my.cnf:
 
         -------
         my.cnf:
         -------
 
         [mysqld]
         ssl
         ssl-key=/somepath/server-key.pem
         ssl-cert=/somepath/server-cert.pem
         ssl-ca=/somepath/ca.pem
         ssl-capath=/somepath/
         ssl-cipher=DHE-RSA-AES256-SHA:AES128-SHA
         # mysql 5.6.3 or later
         ssl-crl=/someCrlPath/some-crl.pem
         ssl-crlpath=/someCrlPath/
         # mysql5.7 or later require all connections to be encrypted
         require_secure_transport server 
 
     After making changes to my.cnf, be sure to restart your mariadb service.
 
     The key means private key here, and should be kept secured.
     The cert is a certificate acting like a public key, signed by a trusted authority (CA).
 
     If a key and cert are available, that means you can authorize.
     And it proves the key exists. The key is not sent to the other party. The cert is.
     If a ca is available it can show what certs to trust.
 
     You do not need all the settings, but some versions of MariaDB
     do not activate SSL unless at least one of these is found: key, cert, ca, capath, cipher 
     If you configure a key for the server or client, you will also provide its cert.
 
     We cannot teach you how to create SSL certificates here.
     There are many websites including MariaDB that have information about
     making keys and certs and ca.
 
     If you just add the ssl option to the top,
     it will try to use SSL, or make it available.
 
     The ca is the certificate authority cert that you are using.
     It could be just a local self-signed authority you made up, 
     or it can be a commercial authority like veriSign.
     This typically is used to sign the certificate for the 
     server and users. The capath is a directory where ca-certs exist (OpenSSL only).
 
     The crl is a certificate revocation list. (OpenSSL only).
     The crlpath is a directory where revocation lists exist (OpenSSL only).
     This crl options are a new feature in 5.6.3, not sure it works right yet.
 
     After making a key for the server, and signing a cert for it with ca,
     you can create SSL connections.
 
     Do not specify a passphrase when creating your server keys.
 
     The cipher setting is a colon-separated list of SSL ciphers that are supported.
 
     The security files like certs etc. that are specified in the above settings
     must be readable by the unix account that mysqld runs under, default is "mysql".
 
     SELinux or apparmor may block access to certain locations.
     /etc/mysql is the default location for .pem files on some platforms.
 
     yaSSL, which is still often used with the MySQL Community Edition, 
     expects keys to be in the PKCS #1 format and doesn't support the PKCS #8 format used by OpenSSL 1.0 and newer. 
     You can convert the key to the old format using openssl rsa:
      openssl rsa -in key_in_pkcs1_or_pkcs8.pem -out key_in_pkcs1.pem
 
     yaSSL requires that all components of the CA certificate tree be contained within a single CA certificate file
     and that each certificate in the file has a unique SubjectName value.
     To work around this limitation, concatenate the individual certificate files comprising the certificate tree
     into a new file and specify that file as the value of the --ssl-ca option. 
     For example,
 
         cd my-certs-dir
         cat ca-cert.pem server-cert.pem (etc) > yaSSL-ca-cert.pem
         chmod +r yaSSL-ca-cert.pem
 
     Now use my-certs-dir/yaSSL-ca-cert.pem for certificate authority (ca) for clients.
 
     These are the SSL settings which can be placed into your hg.conf for CGIs or .hg.conf for utility programs:
 
         db.key=/sompath/someuser-key.pem
         db.cert=/sompath/someuser-cert.pem
         db.ca=/somepath/ca.pem
         db.caPath=/somepath
         db.crl=/someCrlPath/some-crl.pem
         db.crlPath=/someCrlPath/
         db.verifyServerCert=1
         db.cipher=DHE-RSA-AES256-SHA:AES128-SHA
 
     The key and certificate for "someuser" above are signed by a ca.
 
     The verifyServerCert setting if it exists tells the client
     to verify that the CN field in the server's cert matches the 
     hostname to which it is connecting. This prevents Man-In-the-Middle attacks.
 
     The caPath and crlPath options only work with OpenSSL.
 
     The example shows the most common use for the profile "db".
     But the SSL settings work with any profile in the hg.conf file.
 
     Of course you can stick SSL settings into your [client] section of my.cnf,
     but the CGIs and utils would not see them.  Only mysql and hgsql would see them.
 
 
     Configuring SSL requirements for MariaDB user accounts:
 
     You can tell MariaDB to require SSL for a user's account like this:
 
         GRANT ALL PRIVILEGES ON *.* TO 'someuser'@'%'
           REQUIRE SSL;
 
     You can tell MariaDB to use SSL for a user's account and to
     further require the client to use their key and x509 certificate to connect by saying:
 
         GRANT ALL PRIVILEGES ON *.* TO 'someuser'@'%'
           REQUIRE x509;
 
     There are more-specific requirements that may be added:
 
         GRANT ALL PRIVILEGES ON *.* TO 'someuser'@'%'
           REQUIRE SUBJECT '/C=US/ST=CA/L=Santa Cruz/O=YourCompany/OU=YourDivision/CN=someuser/emailAddress=someuser@YourCompany.com'
               AND ISSUER  '/C=US/ST=CA/L=Santa Cruz/O=YourCompany/OU=YourDivision/CN=YourCompanyCA/emailAddress=admin@YourCompany.com'
               AND CIPHER  'DHE-RSA-AES256-SHA';
 
     You can see the cert details like this:
          openssl x509 -in /somepath/someuser-cert.pem -text
 
     In later versions of MariaDB, it is a requirement that the CN of the CA cert must DIFFER 
     from the CN of the user and server certs.
 
     Further MySQL SSL documentation is available from 
 <https://dev.mysql.com/doc/refman/5.6/en/creating-ssl-files-using-openssl.html> 
 
 # Local Git repository (aka: "the source tree")
 
 Use the following procedures to create your own personal copy of the kent source
 tree where you can have your own edits that are not part of the development at
 UCSC.  This is useful for mirror sites that have their own customizations in
 the source tree for local circumstances. It will also be necessary if you want to 
 add your own tracks to your mirror (see next section).
  
 Install Git software version 1.6.2.2 or later. See the Git Community Handbook
  installation (<https://git-scm.com/book/en/v2/Getting-Started-Installing-Git>) and setup
  (<href='https://git-scm.com/book/en/v2/Getting-Started-First-Time-Git-Setup>) instructions, as well
  as our Installing Git (<http://genomewiki.ucsc.edu/index.php/Installing_git>)
  Genomewiki page.
 
 Start an initial Git local repository:
 
     git clone git://genome-source.soe.ucsc.edu/kent.git
  
 or, if a firewall prevents git daemon port 9418, use:
  
     git clone http://genome-source.soe.ucsc.edu/kent.git
  
 The kent source tree will be imported to the current working directory in a
 directory named ./kent/.
 
 Track the beta branch at UCSC repository: Most users want to use the beta branch, which has tested, released versions of
  the browser. To create a beta tracking branch:
  
     cd kent
     git checkout -t -b beta origin/beta
  
 The -b creates a local branch with name "beta", and checks it out.
 The -t makes it a tracking branch, so that 'git pull' brings in updates from
 origin/beta, the "real" beta branch in our public central read-only repository.
 
 To get the latest UCSC release, from anywhere within the kent source tree:
  
     git pull
 
 Updates: UCSC generally updates the origin/beta branch every three weeks. If you are 
  updating database tables for a mirror site, we recommend that you update the
  source at the same time, as source code is sometimes modified to include
  operations on new columns that have been added to database tables.
  
 For instructions on keeping local tracks separate from UCSC Genome Browser
 tracks created at UCSC and mirrored from there, see the section "Adding tracks
 to the browser" below.
 
 # Adding your own track groups to the browser
 
 If you want to add your own tracks (see next section), you probably want to put them into 
 a separate track group, so they are visually separated from the tracks provided by UCSC.
 
 The MariaDB table `grp` contains the list of all track groups. If you rsync the data
 from UCSC on a regular schedule, the table would be overwritten each time. To avoid this,
 you can create an empty table with the same schema, e.g. in the database hg38:
 
     CREATE TABLE grp_local LIKE grp;
     
 You can then use the MariaDB INSERT statement to add a new track group to this
 table, specify the name, label, priority and whether the group should be closed
 by default (most are open by default).
 
     INSERT INTO grp_local VALUES ('test', 'This is my group', 1, 0);
 
 Then, edit cgi-bin/hg.conf and add a line like this:
 
     db.grp=grp_local,grp
 
 This means that grp_local is added to the contents of grp and grp_local has higher priority, so you can override
 the UCSC-provided default groups, if needed.
 
 This will not have any effect yet. First you need to add a new track that uses your new group.
 You can use your new group's `name` using the "group" statement in trackDb (see the next section).
 
 All tracks with a group not in the grp table will end up in the group "Experimental" at the bottom of the page.
 
 # Adding your own tracks to the browser
 
 A track needs two items to make it exist in the browser:
 
 1.  A database table with the track data
 2.  An entry in a database table: trackDb_localTracks
     Built from track specifications in your trackDb.ra file.
     The format of the trackDb.ra file is explained at
     <http://genome.ucsc.edu/goldenPath/help/trackDb/trackDbDoc.html>
     The correspondence between the database table and the trackDb.ra
     definition is in the name used on the 'track' line in the
     trackDb.ra file.  Your database table name is defined by the 'track'
     definition line.
 
 To direct the genome browser to this trackDb_localTracks table to use as extra trackDb
 definitions, add this line to your cgi-bin/hg.conf file:
 
     db.trackDb=trackDb_localTracks,trackDb
 
 The order matters. Any definitions for tracks
 in trackDb_localTracks will override any definitions for the
 same named tracks in trackDb.  You can then override the
 standard definitions for UCSC-defined tracks.
 The usual case will be that your tracks are unique to your
 local installation.
 
 Almost all of the database tables have specific loader
 programs to load the track data.  The loader programs
 also verify the data before it is added to the table,
 and they create the proper indexes on the table to allow
 efficient display by the genome browser.
 
 By far the most common format of track data is the BED format.
 See also: <http://genome.ucsc.edu/FAQ/FAQformat.html#format1>
 for a description of BED file formats.
 
 A typical BED file format is loaded into a database table with
 the loader: hgLoadBed
 For example, to load the data from the file: data.bed into
 the table named: bedExample
 
     hgLoadBed hg17 bedExample data.bed
 
 You then add a section that starts with the line "track bedExample" to your trackDb.ra file,
 run hgTrackDb to create the trackDb_localTracks database table and the table should appear, 
 as long as trackDb_localTracks has been added to hg.conf as explained before.
 
 There are a variety of file formats: GFF, GTF, PSL, WIG, MAF as well as
 a variety of specialized data types.  All the loader programs can be seen
 in the source tree as subdirectories in: src/hg/makeDb/
 
     cd src/hg/makeDb
     ls -d hg*
 
 The build instructions for the browser code do not include
 instructions for building all of the loaders, or other utilities
 in the kent source tree.  This is because there are literally
 hundreds of utilities,  345 at last count, that are not needed
 for ordinary browser development.  In most cases a developer will
 need only a couple of the loaders and utilities.  Since the libraries
 were built for the CGI binaries, to build any utility or
 loader, simply go into its directory and run a 'make'. If you do not have 
 the kent tree source repository cloned with git yet onto your own disk,
 please go back to the previous section and do that now.
 
 For our purposes here, we need for example, for BED format tracks:
 
 1. hgLoadBed
 2. hgTrackDb
 3. hgFindSpec
 
 To build the three loaders mentioned, go to the three directories in the kent git source repository:
 
     src/hg/makeDb/hgTrackDb/
     src/hg/makeDb/hgFindSpec/
     src/hg/makeDb/hgLoadBed/
 
 And run a 'make' in each one.  The resulting binary is placed
 in: $HOME/bin/$MACHTYPE
 This binary directory should be in your PATH, or make this directory
 be a symlink to some binary directory that is in your PATH
 and you have write permission to.
 
 See also: new assistant scripts as of March 2010 in the src/product/scripts/
 	directory here to fetch and build the source tree.
 
 If you want to build all the utilities and all database
 loaders now, perform the following 'make' commands in your source tree:
 
     cd src
     make clean
     make libs
     cd hg
     make
     cd ../utils
     make
 
 This builds everything cleanly, all CGI binaries, all database
 loaders, all utilities.  Perform this sequence each time you
 do a 'git pull' on your source tree.  The 'make clean' step
 is especially important since the makefile hierarchy does not
 have built in dependencies and will not rebuild items that
 depend upon each other.  The traditional dependency on the
 source tree libraries is taken care of because a make in any
 directory that produces a binary will always re-link the
 binary every time, thus always picking up any potentially new
 library.
 
 With those three loader programs built, you can now load BED
 format tracks, and build the trackDb_localTracks table as
 mentioned next.
 
 The hgTrackDb and hgFindSpec loaders are used to build the trackDb and
 hgFindSpec tables in the database. You can obtain example
 trackDb entries from the source tree hierarchy: src/hg/makeDb/trackDb/
 in any of the *.ra files.  And you will need to refer to the README
 file in that directory for information about options you can use with
 each track type or use our full trackDb.ra documentation at 
 <http://genome.ucsc.edu/goldenPath/help/trackDb/trackDbDoc.html>.
 
 To work independently of the UCSC source tree,
 establish your own trackDb.ra files outside the UCSC source tree in
 a directory of your choice under your control.  Then, to load them
 into the database, run the hgTrackDb command with this
 simple makefile in the directory where your .ra file exists:
 	
     trackDbSql=/path/to/kent/source/tree/src/hg/lib/trackDb.sql
     DB=hg19
 
     all::
             hgTrackDb . ${DB} trackDb_localTracks ${trackDbSql} .
 
 This hgTrackDb command reads your trackDb.ra file and converts it
 into row entries for each track specified in it into row contents
 in this new table trackDb_localTracks.
 
 The DB= specification is your database of interest, this example: hg19
 This loads your local specific table trackDb_localTracks in the database.
 This name trackDb_localTracks is not special, just different than
 the ordinary trackDb table.  It should have some meaning to anyone
 in your environment and not be the same name as any UCSC database
 table.  The two '.' arguments in the command above refer
 to directory names.  Since you have no hierarchy of levels in this
 single directory, unlike in the source tree trackDb hierarchy, the
 '.' arguments refer to the current directory.
 
 See also:
 
 * A similar overview: <http://genomewiki.ucsc.edu/index.php/Local_tracks_at_mirror_sites>
 * TrackDb.ra track configuration format: <http://genome.ucsc.edu/goldenPath/help/trackDb/trackDbDoc.html>
 
 # Adding a new, custom (non-UCSC) genome to the browser
     
 Please note that setting up an [assembly hub](http://genomewiki.ucsc.edu/index.php/Assembly_Hubs) 
 is a lot easier than adding a genome to a local mirror.
 
 The browser can be made to operate with a bare minimum of tables
 for the purpose of demonstrating the CGI binaries are functioning.
 
 The only tables you need to load for this are:
 
 1. all tables in the hgcentral database
 2. six tables in the human genome
 
 Create an empty hgcentral database:
 
     $ hgsql -e "create database hgcentral;" mysql
 
 Load all tables into the hgcentral database.
 Copy all the mysql data files from
 
     rsync -avP rsync://hgdownload.soe.ucsc.edu/mysql/hgcentral/ .
 
 directly into the MySQL data area for your hgcentral database.
 (something usually like /var/lib/mysql/hgcentral/)
 
 Or load this database with mysql/hgsql commands and the hgcentral.sql
         text file dump of these tables from:
 
     rsync -avP rsync://hgdownload.soe.ucsc.edu/genome/admin/hgcentral.sql .
 
 And then six tables for the latest human database.
 
 The gateway page always needs a minimum human database in order
 to function even if the browser is being built for the primary
 purpose of displaying other genomes.  This default can currently
 be changed in the source tree in src/hg/lib/hdb.c
 (to be done: specify this default in hg.conf file)
 
 Start with an empty database, for example hg18:
 
     hgsql -e "create database hg18;" mysql
 
 Again, copy the MariaDB files directly from the download
 server, for example hg18:
 
     rsync -avP rsync://hgdownload.soe.ucsc.edu/mysql/hg18/ .
 
 (beware, this is several TB of data) into your MariaDB data area.  Or load these tables from the text SQL
 dumps from:
 
     rsync -avP rsync://hgdownload.soe.ucsc.edu/goldenPath/hg18/database/ .
 
 (beware, this is several TB of data)
 
 The minimal set of tables required are:
 
     grp
     trackDb
     hgFindSpec
     chromInfo
     gold
     gap
 
 With this set of six tables the gateway page will
 begin to function and the browser page and table browser
 will function.  Other browser functions are not ready yet without
 additional tables and databases.  This is a bare minimum just to
 demonstrate the CGI binaries are working.
 
 This will all work even without copying any files for the /gbdb/
 data area, although most functions will not work, such as fetching
 the DNA sequence from a browser view.  The DNA sequence for
 an assembly is found in, for example hg18: /gbdb/hg18/nib/chr*.nib
 Some assemblies have all the DNA sequence in a single .2bit file,
 for example: /gbdb/mm8/mm8.2bit
 
 # Modifying the source code
 
 If you want to make changes to the source code, contact us first via the
 mailing list, to make sure that there is no option in development or an
 undocumented way to solve your problem. 
 
 If you need to change the code, make sure to isolate your changes into a
 single function, if possible. Using git, merge your branch into our "beta"
 branch, ideally for every release, then recompile.  If your changes could be
 useful for someone else, and you are getting tired of updating them to keep up
 with our changing code base, consider submitting them as a pull request, so we
 can integrate it into the main code base and you do not have to worry about
 updating them anymore.
 
 Once you have git setup properly, merging your changes into our current
 release should be as easy as this:
 
     git pull # get new version
     git checkout beta # switch to our stable branch
     git merge myChangesBranch # merge your changes into the beta branch
     make -j 20 cgi-alpha # compile and put CGIs into /usr/local/apache/cgi-bin
 
 # Custom Track Database
 
 Without any specific hg.conf configuration, custom track data
 is kept in flat files in the /trash/ct/ directory. 
 It is much more efficient to load them into a MariaDB database.
 This article discusses the steps required to enable this function.
 
 1. Summary configuration
 
     * database loader binaries hgLoadBed, hgLoadWiggle and wigEncode are
 	installed in /cgi-bin/loader/ - these are installed via the normal
 	'make cgi' in the source tree kent/src/hg/ directory or via rsync.
         They are probably aleady in your cgi-bin directory.
     * an empty customTrash database has been created on the MariaDB host -
 	create this manually once, the MariaDB host name is a configuration
 	item, the database name customTrash is not a configuration item
     * temporary read-write data directory /data/tmp has been created
 	with read/write/delete enabled for the Apache server effective
 	user, this directory name is a configuration item
     * configuration items are specified in /cgi-bin/hg.conf/ - this will
 	turn on the function
     * for command line access to the database, create a special
 	~/.hg.ct.conf to be used with the environment variable HGDB_CONF
     * create a cron job to run a cleaner script to expire and remove
 	older tables from the database - dbTrash command is used for this
 	purpose
 
 2. Host and database name
 
     For performance and security considerations, the MariaDB host for the
     custom track database can be a separate machine from the ordinary MariaDB
     host that usually serves up the assembly databases or the hgcentral
     database. It is not required that the custom track database be on a
     separate MariaDB server. The specification of the host machine is placed
     in the /cgi-bin/hg.conf file, for example a host machine called
     "ctdbhost":
 
         customTracks.host=ctdbHost
 
     The database name used on this host is fixed at customTrash which is a
     define in the source tree file hg/inc/customTrack.h
 
     Edit /cgi-bin/hg.conf configuration items:
 
     The following items must be specified in /cgi-bin/hg.conf to enable this
     function:
 
         customTracks.host=ctdbhost
         customTracks.user=ctdbuser
         customTracks.password=ctdbpasswd
         customTracks.useAll=yes
 
     Establish this user account and password in MariaDB with db and user
     privileges:
 
     Select, Insert, Update, Delete, Create, Drop, Alter, Index
     for example with your MariaDB root user account:
 
         hgsql -hctdbhost -uroot -p -e \
             "GRANT SELECT,INSERT,UPDATE,DELETE,CREATE,DROP,ALTER,INDEX" \
             on customTrash.* TO ctdbuser@yourWebHost IDENTIFIED by 'ctdbpasswd';" mysql
 
     Optionally, a temporary read-write directory used during database
     loading can be specified:
 
         customTracks.tmpdir=/data/tmp
 
     The default for this is /data/tmp and should be created with
     read/write/delete access for the Apache server effective user.
     It should be on a local filesystem for best access speed, not via NFS.
 
 3. Database loaders:
 
     The database loaders used to load custom tracks are the standard loader
     commands found in the source tree, hgLoadBed, hgLoadWiggle and
     wigEncode. They are installed into /cgi-bin/loader/ with a 'make cgi'
     from the source tree directory kent/src/hg/ These loaders are used by
     the cgi binaries hgCustom, hgTracks, and hgTables to load custom tracks
     into the database. They are operated in an exec'd pipeline fashion, the
     code details can be see in src/hg/lib/customFactory.c
 
 4. Command line access:
 
     Since the MariaDB host may be different than your ordinary MariaDB host, you
     will need to create a unique $HOME/.ct.hg.conf file to be used in the
     case where you want to manipulate this separate database with the kent
     source tree command line tools. This unique .ct.hg.conf is merely a copy
     of your normal .hg.conf file but with a different host/username/password
     specified:
 
         db.host=ctdbhost
         db.user=ctdbuser
         db.password=ctdbpasswd
         central.db=hgcentral
 
     Remember to set the privileges on this hg.conf file at 600:
 
         chmod 600 $HOME/.ct.hg.conf
 
     To enable the use of this file for subsequent command line operations,
     set the environment variable HGDB_CONF to point to this file, for
     example in the bash shell:
 
         export HGDB_CONF=$HOME/.ct.hg.conf
 
     With that in place, you can examine the contents of the customTrash
     database:
 
         hgsql -e "show tables;" customTrash
 
     This unique hg.conf file will also be used by the cleaner command
     dbTrash
 
 5. Cleaner script
 
     The database and the temporary data directory /data/tmp need to be kept
     clean. This is similar to the current cleaner script you have running on
     your /trash filesystem. In this case there is a specific source tree
     utility used to access and clean the database. The temporary data
     directory /data/tmp would stay clean if each and every loaded custom
     track was successfully loaded. In the case of badly formatted or illegal
     data submitted for the custom track, the database loaders do not remove
     their temporary files from /data/tmp This /data/tmp directory can be
     kept clean with, for example, an hourly cron job that performs:
 
         find /data/tmp -type f -amin +10 -exec rm -f {} \;
 
     This would remove any file not accessed in the past 10 minutes.
 
     The database cleaner command dbTrash should be run as a cron job
     encapsulated in a shell script something like this, which maintains a
     record of items cleaned to enable later analysis of custom track
     database usage statistics:
 
         #!/bin/sh
 
         DS=`date "+%Y-%m-%d"`
         YYYY=`date "+%Y"`
         MM=`date "+%m"`
         export DS YYYY MM
 
         mkdir -p /data/trashLog/ctdbhost/${YYYY}/${MM}
         RESULT="/data/trashLog/ctdbhost/${YYYY}/${MM}/${DS}.txt"
         export RESULT
 
         /cluster/bin/x86_64/dbTrash -age=48 -drop -verbose=2 > ${RESULT} 2>&1
 
     Running this once a day will remove any tables not accessed within the
     past 48 hours. The dbTrash command is found in the source tree in
     kent/src/hg/dbTrash
 
     The /trash directory can be kept clean with the following two commands,
     one to implement an 8 hour expiration time on most files, the second to
     implement a 48 hour expiration time on custom track files:
 
         find /trash \! \( -regex "/trash/ct/.*" -or -regex "/trash/hgSs/.*" \) \
             -type f -amin +480 -exec rm -f {} \;
         find /trash \( -regex "/trash/ct/.*" -or -regex "/trash/hgSs/.*" \) \
             -type f -amin +2880 -exec rm -f {} \;
 
 6. metaInfo and history
 
     You will note two special and persistent tables in the customTrash
     database: metaInfo and history. The metaInfo table records a time of
     last use for each custom track table and a useCount for statistics. The
     time of last use is used by the cleaner utility dbTrash to expire older
     tables. The history table is the same as the history table in the normal
     assembly databases. The loader commands, hgLoadBed and hgLoadWiggle
     record into the history table each time they load a track. The cleaner
     command dbTrash also records in the history table statistics about what
     it is removing.
 
 7. Turning On Considerations
 
     Please note, if there are currently existing custom tracks in /trash/ct/
     files, at the time of adding the configuration items to
     /cgi-bin/hg.conf/ those existing tracks will be converted to database
     versions upon their next use by the user. Therefore, to enable this
     function on the round-robin WEB servers, we will need to do the update
     to /cgi-bin/hg.conf in as much a simultaneous manner as possible.
     Perhaps something like a shell script to do eight background rsync's all
     at the same time.
 
 8. Use of trash files with the database on
 
     When the custom tracks database is in use, there are still small files
     kept in /trash/ct which become the reference pointers to the actual
     database tables belonging to that custom track. The standard trash
     cleaner script should still be kept running to clean these files.
 
 9. Known difficulties
 
     For the case of a custom track submission that contains more than one
     track set of data, in the case where one of the sets of data is illegal
     and causes a loading problem, even though some sets of data may have
     loaded successfully, the submitting user will see an error about the
     corrupted data, and they would need to correct their data submission to
     get all tracks successfully loaded.
 
     It remains to be seen just how good the error reporting system is for
     illegal data.
 
 # Debugging the CGI binaries
 
 The typical sign of trouble is an Error 500 display in your
 web browser when accessing the CGI binaries, and the following
 message in your Apache error log:
 
     [Fri Mar 25 11:02:40 2005] [error] Premature end of script headers: hgTracks
 
 This is usually a simple configuration problem.  Items to verify:
 
 1.  the hg.conf file in the cgi-bin directory specifies the correct
 	user names and passwords for MariaDB database access.
 	See also the section "MariaDB Setup" below.
 2.  The cgi-bin directory is set to permissions 755 and not 775 or 777
 	When permissions are too permissive for this directory, Apache
 	errors out with suexec permission violations.
 3.  Verify change history of the database hgcentral.
     Rarely, changes in this database require corresponding changes
     in the source code.  Make sure your code and version of
     hgcentral are synchronized.  Newer versions of hgcentral
     database with old source code are OK.  The problem is when
     you have new source code that expects new features in hgcentral.
 
 If these items are OK, then you can check the actual operation of
 a cgi binary.  Go to the source tree directory of the cgi binary,
 for example hgTracks:
 
 	kent/src/hg/hgTracks
 
 In this directory, run a 'make compile' to produce a binary that
 is left in this directory.  This binary can be run from the command
 line:
 
     ./hgTracks
 
 By itself with no arguments, it should produce the default tracks
 display HTML page for the Human genome.  This assumes you have set
 up your $HOME/.hg.conf file to allow access to the MariaDB databases.
 (See also: section "MariaDB Setup").  A binary execution failure should
 be obvious at this stage of the game.  If it exits because of SIGSEGV
 we can run it under a debugger for specifics.  More on this below.
 
 If the problem is specific to a particular set of tracks being
 displayed, or particular genomes or options, command line arguments
 can be given to these CGI binaries to provide the URL inputs
 that a CGI binary would normally see.
 
 To prepare the binaries for operation under a debugger, go to
 the src/inc directory and edit the common.mk configuration file.
 Change "COPT=-O" to read: "COPT=-g"
 GNU gcc will allow "-O" with "-g", and some bugs will only exhibit
 themselves with -O on.  However the optimizations with -O can
 sometimes confuse the debugger's sense of location due to
 optimization rearrangement of code.
 Also eliminate the -Wuninitialized option from the HG_WARN definition
 to avoid constant warnings about that being incompatible with -g.
 
 Rebuild the source tree:
 
     cd kent/src
     make clean
     make libs
     cd hg/hgTracks
     make compile
 
 The hgTracks binary will now have all symbol information in it and
 it can be operated under a debugger such as ddd (or gdb, etc...).
 
 For the case of specific options or tracks causing problems,
 to find the full set of options in effect for the failure case,
 when your WEB browser is at the Error 500 display page, edit
 the displayed URL in your WEB browser to call the cgi binary cartDump:
 http://<your server>/cgi-bin/cartDump 
 
 This will display all environment variables in effect at the time
 of the crash.  Most of the track display options that are marked
 as "hide" can be ignored.  That is their default setting already.
 The important ones are the db, position, and specific options for
 the track under consideration.  The command line can be formatted
 just as if it was a URL string.  For example:
 
     ./hgTracks "db=hg17&trackControlsOnMain=0&position=chr4:56214201-56291736"
 
 Or with spaces between the arguments:
 
     ./hgTracks db=hg17 trackControlsOnMain=0 position=chr4:56214201-56291736
 
 Remember to protect special characters on the command line from
 shell interpretation by appropriate quoting.
 
 At this point, running under a debugger, with a command line for
 specific options, a crash of the binary should give you some clue
 about the problem by checking the stack backtrace to see what function
 is failing.  It is highly doubtful you will be finding problems
 in the source code for the crashes.  The almost universal cause
 for failure are the data inputs to the binaries.  For example,
 violations of the SQL structures expected from the database tables.
 Missing data files in the /gbdb/ hierarchy, and so forth.
 
 If you are developing code for special track displays, the most
 common form of problem is a memory violation while using some
 of the specialized structures, hash lists, etc.  Your stack backtrace
 will usually highlight these situations.
 
 In order to determine the URL being used by the browser CGIs to pass
 to in the debugger, you need to force the browser to use GET http
 requests rather than POST.  Try adding &formMethod=GET to an URL.
 Not all forms pay attention to that input, but when they do it
 generally looks like this:
 
     hPrintf("<FORM ACTION=\"%s\" NAME=\"mainForm\" METHOD=%s>\n",
     getScriptName(), cartUsualString(cart, "formMethod", "POST"));
 
 If you add &formMethod=GET and a subsequently fetched form is still
 posting, you might need to alter the "<FORM..." statement to use the
 cartUsualString.
 
 The hg18 hgTracks config page generates a GET URL that is too long for
 FireFox, so after debugging hgTables, you will probably want to add
 &formMethod=POST to an URL (or clear cart, load session etc).
 
 One thing that does not work with GET is "upload file" inputs.
 
 # HTTPS Certificate Check for Verification Settings are: abort warn none
 # currently the default is warn
 httpsCertCheck=warn
+# domains to whitelist, skip cert checking, space-separated list
+httpsCertCheckDomainExceptions=somedomain1.com somedomain2.edu
+
 
 # Proxy support
 
 net.c now has support for http(s) proxy servers
 which may be required by some installations
 to get through the firewall to external resources
 such as (but not limited to) for example 
 bigWig or bigBed data via custom track bigDataUrl.
 
 One must add the setting "httpProxy", "httpsProxy", "ftpProxy" to hg.conf
 
     httpProxy=http://someProxyServer:3128
     httpsProxy=http://someProxyServer:3128
     ftpProxy=ftp://127.0.0.1:2121
 
 If the proxy server requires BASIC authentication
 
     httpProxy=http://user:password@someProxyServer:3128
     httpsProxy=http://user:password@someProxyServer:3128
 
 where user and password may need URL-encoding
 if they contain special characters such as
 ":" and "@".
 
 If you wish to exclude domains from proxying,
 create a comma-separated list of domain-suffixes.  
 If a domain ends with an entry from this list, the proxy will be skipped.
 
     noProxy=ucsc.edu,mit.edu
 
 
 The httpProxy and httpsProxy URLs should use http protocol, not https.
 One reason for this is that https sessions would end up doubly-encoded.
 
 If you are debugging your proxy configuration, you can use this hg.conf setting
 to turn on logging to stderr.
 
 logProxy=on
 
 It is not meant to be left on in production.
 Your proxy server should have its own logging features.
 
 net.c also responds to environment variables http_proxy, https_proxy, ftp_proxy, no_proxy and log_proxy.
 
 
 # The UDC local cache directory
 
 The udcCache allows tracks that are either installed tracks
 or custom tracks of the above mentioned types to cache data 
 that they have already fetched via URL.  This allows data to 
 reside elsewhere and only download the parts
 needed on demand.  The datablocks are usually
 compressed and have an efficient random access
 index. They are accessed from a remote location
 via URLs such as HTTP, HTTPS, FTP.
 
 * udcCache means URL-Data-Cache
 * BBI files use the udcCache.
 * BBI means Big Binary Indexed and includes file types such as BigBed (.bb) and BigWig (.bw).
 * UCSC BAM file support may also use the udcCache
 
 By default, udcCache stores files in /tmp/udcCache
 
 However, you may include the following in your hg.conf
 and then let your regular trash cleaning scripts
 clean out the old udcCache automatically as well:
 
     # directory for temporary bbi file caching
     udc.cacheDir=../trash/udcCache
 
 Notice that this path is relative to your 
 cgi executable directory which is the 
 current directory when the cgi starts up.
 On some systems this directory is called cgi-bin/.
 
 # Activating CRAM support for the Genome Browser.
 
 The UCSC Genome Browser is capable of displaying tracks from both the BAM and
 CRAM file formats.  While BAM tracks provide all of the required data within
 the file, however, CRAM tracks depend on external "reference sequence" files
 (see http://www.ebi.ac.uk/ena/software/cram-toolkit for more information about
 the CRAM format).  A bit of information on how the Browser works with these
 files is included below.  For installation instructions, skip to the numbered
 steps at the end of this file.
 
 The directory that Genome Browser CGIs check for CRAM reference files is set
 with the cramRef setting in hg.conf.  For example, the following setting is
 used on our production servers:
 
     cramRef=/userdata/cramCache
 
 When loading tracks from the CRAM file format, CGIs will look for reference
 sequences in that directory.  The filename of each reference sequence should be
 the MD5 or SHA1 checksum of the reference sequence as described at
 http://www.ebi.ac.uk/ena/software/cram-reference-registry.  If a CGI is unable
 to find the reference sequence file for a CRAM track, it will next check the
 cramRef/pending/ directory to see if a request for that reference sequence has
 already been made, and the cramRef/error/ directory to see if a previous
 attempt at downloading that reference sequence resulted in an error.  If none
 of those files are found, the CGI will then create a request file in the
 cramRef/pending/ directory.  The name of the request file will be the MD5 or
 SHA1 sequence checksum, as specified in the CRAM data file.  The contents of
 the request file will be the URL to download that reference sequence.  A
 separate tool can then be used to download reference sequences listed in the
 pending/ directory and place them into cramRef/.
 
 Steps to set up CRAM track support:
 
 1.  Add the hg.conf setting cramRef.  The value should be the path (relative
     or absolute) to a directory where CRAM reference sequences are stored.
 
 2.  Inside the cramRef directory create subdirectories called "pending" and
     "error".  The apache user must have read/write permissions for the pending/
     directory, and at least read permissions for the cramRef/ and error/
     directories.  
     If you plan to manually load all CRAM reference sequences for your tracks into
     the cramRef directory, track support is now complete.  If you prefer to
     have reference sequences automatically downloaded and placed in that directory
     (e.g., for user-submitted custom tracks), continue to step 3.
 
 3.  Add a cron job to run a script that parses files in the cramRef/pending/
     directory, downloads the corresponding reference sequence files, and places
     those sequence files in cramRef/.  Error messages during file retrieval
     should be placed in cramRef/error/.  An example script is provided in this
     repository at kent/src/product/scripts/fetchCramReference.sh.  The account
     that runs this script must have read/write permissions for the cramRef/,
     cramRef/pending/, and cramRef/error/ directories.
 
 # Using FreeType font support for anti-aliased text
 
 The Genome Browser can use a set of hard-coded Type1 fonts for text display
 in hgTracks.   The fonts are NOT distributed as part of the Genome Browser files
 but they exist natively on the UNIX systems we use in our production environment.
 To support FreeType font drawing on your system you may need to install these files if they
 are not already present. On most systems, they exist in one of three directories:
 
     /usr/share/X11/fonts/urw-fonts
     /usr/share/fonts/default/Type1
     /usr/share/fonts/type1/gsfonts
 
 To turn on the FreeType font rendering you need to add this line to your hg.conf file:
 
     freeType=on
 
 By default, the Genome Browser looks in the directory 
 
     /usr/share/fonts/default/Type1 
 
 for the font files it expects to find. If you have these fonts in a different directory, you need
 to add this line to your hg.conf file:
 
     freeTypeDir='<apache accessible directory path with fonts in it>'
 
 The names of the font files that the Genome Browser expects and their md5sums are in the following table:
 
     5624bc04bbd862287bda3c44b15e90d6  a010013l.pfb
     6883f53d0d140f972480f179bb5e4e3b  a010015l.pfb
     db21f79bac990fa7e3de6d4cc6f54020  a010033l.pfb
     c3d0c3af6bc183010204ca923fb98e83  a010035l.pfb
     33265074c9c45c356f90de9cc47259b3  n019003l.pfb
     9d07b8658622c2e0127628c87fdb9661  n019004l.pfb
     df59ecc7bd232d2355786fd644f13baa  n019023l.pfb
     9f2d4377d9eea95dfdfa705c83a39464  n019024l.pfb
     8f75382bd2620a20aaeb06ab8c591e8f  n019043l.pfb
     28bb40d1700909b2509e2125a1963e2c  n019044l.pfb
     adf4d5565bec1170f0a5810c6984ff55  n019063l.pfb
     57e1a49c39a546c2883375df12111816  n019064l.pfb
     84e347c88eff2e77ed40b020b457bafe  n021003l.pfb
     8721c1175d907d7d484bdaa91d4533ad  n021004l.pfb
     eef0367afaa10b929e528c40c980b941  n021023l.pfb
     7af41ff3536fadcdc27eb9e5cc1c32d3  n021024l.pfb
     db95b702b81c12df1f91d15c8a6c3191  n022003l.pfb
     e97c9af68414fabe157af711b7691df7  n022004l.pfb
     f13fb8e581426a1ffa5fc12b10ad0f34  n022023l.pfb
     f3cd9244150f086434b62d5c5bb559b0  n022024l.pfb
     30aef717b7c68a6b6b7760b764fbd01c  z003034l.pfb
 
 # Building the kent source tree.
 
 In some cases, you may have to modify the source code itself. In these cases, you would need
 to build all the tools and CGI programs from the source code on your machine.
 
 There are scripts available in the git repo src/product/scripts/ directory 
 that can run all of these steps for you with the script:  scripts/kentSrcUpdate.sh
 See the instructions in scripts/README
 
 If you have the kent git repository cloned:
 
 1. Check your shell environment.  It should
 	contain a MACHTYPE variable.  Typical values, for example:
 	i386 i686 sparc alpha x86_64 ppc
 	If there is none, set it to indicate your
 	CPU architecture, for example,
 	MACHTYPE=i686
 	export MACHTYPE
 	You need to do this if your existing MACHTYPE is a long string
 	such as: i686-pc-linux-gnu
 	since this is used as an argument on the command line to gcc
 	which will not work with the - signs in the strings.
 	Typical values: i386 i686 x86_64 sparc ppc
 
 	To determine the machine cpu type of your computer, try
 	one of these uname command options:
 	$ uname -m
 	$ uname -p
 	$ uname -a
 
 	Remember to set this MACHTYPE in your .bashrc or .tcshrc home directory
 	environment files so it will be set properly at your next login.
 
 	The browser code has not been tested by UCSC outside a
 	CentOS Linux on Intel or AMD Opteron environment.
 	Other users do report successful operation on other systems.
 
         Depending upon what libraries you have installed locally, you may want
         to set environment variable USE_SAMTABIX.
 
 	See also:
 	http://genomewiki.ucsc.edu/index.php/Build_Environment_Variables
 
 2.  Create a directory where binaries will be moved to during
 	the build of the source tree:
 	$ mkdir -p ~/bin/${MACHTYPE}
 
 3a. ALTERNATE PATH: 
         If you are going to do a full build anyway, skip this and proceed straight to step 3 below.
         Otherwise, to make a minimal utility build without MariaDB:
 	There are some utilities that depend only on jkweb.a and not jkhgap.a
 	which means they can be compiled without needing MariaDB client installed.
 	To make a utility like pslCDnaFilter without installing MariaDB client:
         # create jkweb.a
           cd kent/src/lib
           make
         # create stringify utility required by some makefiles
           cd kent/src/utils/stringify
           make
         # create pslCDnaFilter utility program
           cd kent/src/hg/pslCDnaFilter
           make
         Proceed similarly for any other such utilities.
         You are done and can stop here.
 
 3.  Create the following shell environment variables:
 
     NOTE: As of mid-October 2013 the makefile build system in the source
           tree will attempt to configure MYSQLINC and MYSQLLIBS with
           the mysql_config command.  To use that automatic configuration,
           eliminate any MYSQLINC and MYSQLLIBS definitions from your shell
           environment and make sure mysql_config can be found in your PATH.
           This option is not perfect and may not function correctly.
           It usually will not use a static linked library which can lead
           to a known issue on the Mac OSX.  See 'Known Problems' item 10 below.
 
         In the case the automatic configuration does not function, you
         can set these variables in your shell environment to override
         the automatic configuration:
 
 	MYSQLINC=/usr/include/mysql
 	MYSQLLIBS="/usr/lib/mysql/libmysqlclient.a -lz"
 	export MYSQLINC MYSQLLIBS
 	Your setting may vary depending upon where your
 	MariaDB is installed.  The above example is typical.
 	If your system does not have this set of include files
 	or this static client.a file, you may need to install
 	the mariadb-devel package to obtain the MariaDB development
 	environment.
 	With that package installed, this command:
 		mysql_config --libs
 	will display the appropriate libraries to link with
 	for your system configuration.  And:
 		mysql_config --include
 	will display the appropriate MYSQLINC directory.
 	The -lz requires a link to the libraries installed in the
 	zlib-devel rpm.
 
 4a. Required SSL support:
 	In order for the libraries to be able to use SSL,
 	for instance to support fetching HTTPS URLs,
 	install openssl.  We are currently using these packages: 
 	openssl-1.0.1e
 	openssl-devel-1.0.1e
         SSL is also useful for accessing bigWig and bigBed over HTTPS.
         The directory on your server should be found automatically.
 
 4b.  In the source tree, perform the following:
 	$ cd kent/src
 	$ make libs
 	At this point, you can build utilities in other parts of
 	the source tree if that is your goal.  Go to the directory
 	of the utility command you want to build and run a 'make'
 	in that directory.  The resulting binary will be placed
 	in $HOME/bin/$MACHTYPE
 
 5.  To continue building the CGI binaries
 	$ cd kent/src/hg
 	$ make compile
 	$ make install DESTDIR=/destination/prefix
 
 	Where "/destination/prefix" is your choice, and
 	this will install the cgi binaries in:
 	/destination/prefix/usr/local/apache/cgi-bin
 
         If your cgi-bin directory is something different than
 	/usr/local/apache/cgi-bin then use the CGI_BIN variable, e.g.:
 	    make install DESTDIR=/var/www CGI_BIN=/cgi-bin \
 		DOCUMENTROOT=/var/www/html
 
 	You can save yourself time and trouble if your Apache is somewhere
 	other than at /usr/local/apache by creating that directory and making
 	symlinks to your actual apache directories.  For example:
 	mkdir /usr/local/apache
 	ln -s /var/www/cgi-bin /usr/local/apache/cgi-bin
 	ln -s /var/www/html /usr/local/apache/htdocs
 	ln -s /var/www/cgi-bin-${LOGNAME} /usr/local/apache/cgi-bin
 
 	With those symlinks in place, a simple 'make cgi' can be used
 	instead of the 'make compile; make install DESTDIR=...' business.
 
         If your apache DocumentRoot is something different than
         /usr/local/apache/htdocs then use the DOCUMENTROOT variable.
         This value should be a full path and should agree with the 
         browser.documentRoot setting in hg.conf; see the section "MariaDB Setup"
         for more details.
 
 	$ make install DESTDIR=/destination/prefix CGI_BIN=/cgi-bin/path DOCUMENTROOT=/usr/local/apache/htdocs
 
 	to install binaries in "/destination/prefix/cgi-bin/path"
 
 	[NOTE:  These 'make' commands assume gnu make is being used]
 
 6.  After source tree updates, the make sequence is:
 	$ cd kent/src
 	$ make clean
 	$ make libs
 	$ cd hg
 	$ make compile
 	$ make install DESTDIR=/destination/prefix
 
 ====================================================================
 Known problems:
 
 1.  A compile/link of a utility has complaints about undefined symbols
 	such as: bind, accept, listen, gethostbyname, socket, setsockopt,
 	connect, inet_pton, inet_ntop or h_errno
     To fix this, you need to add '-lsocket -lnsl' to your MYSQLLIBS
     environment variable.  This is typically the case on Solaris systems:
 	MYSQLLIBS="/usr/lib/mysql/libmysqlclient.a -lsocket -lnsl -lz"
 
 2.  The build fails immediately in the first src/lib/ directory with
 	the compiler issuing a warning about unused variables.
 	Some newer versions of gcc issue these warnings and the
 	src/inc/common.mk file specifies -Werror which causes it to
 	exit on these warnings.  Either remove the -Werror specifications
 	in src/inc/common.mk or add the -Wno-unused-variable to instruct
 	the compiler to allow these warnings without an exit.
 
 3.  The build fails during a link of any program under the src/hg/
 	hierarchy with an error something like:
 	undefined reference to `SSL_CTX_free'
 	undefined reference to `ERR_get_error_line_data'
 	undefined reference to `SSL_read'
 	undefined reference to `SSL_get_error'
 	undefined reference to `SSL_write'
     This error is due to your MariaDB libraries have been compiled with SSL
 	functionality enabled.  To fix this build problem, add '-lssl'
 	to your MYSQLLIBS environment variable to satisify these SSL
 	library functions.
 
 4.  Build fails on Macintosh with an error:
 aliType.c:5: warning: `rcsid' defined but not used
 make: *** [aliType.o] Error 1
 
     The OSTYPE environment variable needs to be set to "darwin".  If your
     shell is bash, it is a shell local variable instead of an environment
     variable as with tcsh.
 
     To avoid this error, place an export statement in your $HOME/.bashrc
     environment:
     export OSTYPE
     This causes the OSTYPE variable to be recognized during the
     make and the conditional statements in src/inc/common.mk will
     include the -Wno-unused-variable option in the build.
 
 5.  The build fails with an error:
     gifdecomp.c:274: error: call to function 'gif_out_line' without
 	a real prototype
 
     This happens with newer versions of the gcc compiler.  To avoid the
     build stopping at this point, eliminate the -Werror argument from the
     src/inc/common.mk file.  We will fix this error as soon as we
     get our hands on a newer version of the gcc compiler.
 
 6.  The build fails with an error of this type:
     pipeline.c: In function waitOnExec:
     pipeline.c:351: error: ignoring return value of read, declared with
 	attribute warn_unused_result 
 
     This happens with newer versions of the gcc compiler.  To avoid the
     build stopping at this point, eliminate the -Werror argument from the
     src/inc/common.mk file.  We will fix this error as soon as we
     get our hands on a newer version of the gcc compiler.
 
 7.  Build fails complaining about missing png.h file:
 	pngwrite.c:7:87: error: png.h: No such file or directory
 
     Find out where your png.h file is and set PNGINCL to something like:
     export PNGINCL="-I/opt/local/include/libpng14"
     pointing to the directory where png.h exists.
 
 8.  Build fails at the point of building a CGI binary with the error:
     Undefined symbols:
 	"_png_write_png", referenced from:
 	    _mgSaveToPng in jkweb.a(pngwrite.o)
 	... other png symbols ...
 
     You need to find out where your libpng.a is located.  For example
     it may be in /opt/local/lib/libpng.a  When found, use the PNGLIB
     variable to specify it, for example:
     export PNGLIB=/opt/local/lib/libpng.a
     or equivalent:
     export PNGLIB='-L/opt/local/lib -lpng'
 
 9. Build fails with complains about missing functions dlclose, dlopen:
   /usr/lib/x86_64-linux-gnu/libmysqlclient.a(client_plugin.c.o): In function `add_plugin':
   (.text+0x1ed): undefined reference to `dlclose'
   /usr/lib/x86_64-linux-gnu/libmysqlclient.a(client_plugin.c.o): In function `mysql_client_plugin_deinit':
   (.text+0x28b): undefined reference to `dlclose'
   /usr/lib/x86_64-linux-gnu/libmysqlclient.a(client_plugin.c.o): In function `mysql_load_plugin_v':
   (.text+0x51e): undefined reference to `dlopen'
 
   To add the library that includes these functions, add '-ldl' to the
   MYSQLLIBS string: MYSQLLIBS="/usr/lib/mysql/libmysqlclient.a -ldl -lz"
 
 10. Mac OSX dynamic link with the MySQL/MariaDB libraries results in the following
     run-time error for CGI binaries or command line programs:
 
     dyld: Library not loaded: libmysqlclient.18.dylib
 
     This is a known problem with the dynamic library for MySQL,
     with potential work-arounds offered:
         http://bugs.mysql.com/bug.php?id=61243
 
     Or, you can set the MYSQLINC and MYSQLLIBS shell environment variables
     to the static MySQL library as mentioned in Step 3 above.
 
 11. Genome browser issues error:
 
     "PDF format not available" when trying to export to pdf.
 
     The browser can't find the command 'ps2pdf' which is usually
     found in /usr/bin/ps2pdf and is installed with the 'ghostscript'
     package.  Install the 'ghostscript' package and verify ps2pdf is
     in: /usr/bin/ps2pdf