Hacking INN

    This file is for people who are interested in making modifications to
    INN.  Normal users can safely skip reading it.  It is intended primarily
    as a guide, resource, and accumulation of tips for maintainers and
    contributors, and secondarily as documentation of some of INN's
    internals.

    First of all, if you plan on working on INN source, please start from
    the current development tree.  There may be significant changes from the
    previous full release, so starting from development sources will make it
    considerably easier to integrate your work.  You can check out or clone
    the current development tree using Git from:

        <https://github.com/InterNetNews/inn.git>

    or browse the current development source on Github at:

        <https://github.com/InterNetNews/inn>

    You will need autoconf 2.64 or later to use the development tree.  After
    checking out the tree, run "./autogen" to generate the necessary
    autoconf files.

    Pull requests must complete an automatic build/test cycle with warnings
    enabled.  You can run an equivalent build with "./ci/test".

    Daily snapshots can be found at:

        <https://downloads.isc.org/isc/inn/snapshots/>

Configuring and Portability

    All INN code should be written expecting ANSI C and POSIX.  There is no
    need to attempt to support pre-ANSI compilers, and ANSI-only features
    such as <stdarg.h>, string concatenation, "#elif", and token pasting may
    be used freely.  So far as possible, INN is written to attempt to be
    portable to any system new enough that someone is likely to want to run
    a news server on it, but whenever possible this portability should be
    provided by checking for standard behavior in configure and supplying
    replacements for standard functions that are missing.

    When there is a conflict between ANSI C and C99, INN code should be
    written expecting C99 and autoconf used to patch up the differences.

    Try to avoid using "#ifdef" and the like in the middle of code as much
    as possible.  Instead, try to isolate the necessary portability bits and
    include them in libinn or at least in conditional macros separate from
    the code.  Trying to read code littered with conditional compilation
    directives is much more difficult.

    The shell script configure at the top level of the source tree is
    generated by autoconf from configure.ac and the additional macros in the
    m4 directory, and include/config.h.in is generated by autoheader from
    configure.ac.  At configure time, configure generates include/config.h
    and several other files based on options it was given and what it
    discovers about the target system.

    All modifications to configure should instead be made to configure.ac. 
    The autoconf manual (available using "info autoconf" if you have
    autoconf and the GNU info utilities installed on your system) is a
    valuable reference when making any modifications.

    To regenerate configure, just run "autoconf".  To regenerate
    include/config.h.in, run "autoheader".  Alternately, to regenerate both,
    you can run "./autogen".  Please don't include patches to either
    configure or include/config.h.in when sending patches to INN; instead,
    note in your patch that those files must be regenerated.  These (and all
    other) generated files should not be checked into Git.

    At the time of this writing, autoconf 2.64 or later is required.

    The supporting files for autoconf are in the support subdirectory,
    including the files config.guess and config.sub to determine the system
    name and ltmain.sh for Libtool support.  The latter file comes from the
    Debian package of Libtool, available from
    <https://packages.debian.org/libtool> (ltmain.sh is generated in the
    build-aux subdirectory after building the package with for instance
    debuild -us -uc); the canonical versions of the former two files are
    available from <https://ftp.gnu.org/gnu/config/> (which currently
    redirects to <https://git.savannah.gnu.org/cgit/config.git/tree/>).

    In addition, m4/libtool.m4 and a few other m4 files used by INN are just
    a copy of the corresponding files in the m4 subdirectory of the Debian
    package of the Libtool distribution.  (Using Libtool without using
    automake requires a few odd hacks.)  New versions should be checked in
    periodically when available.  There are no INN-specific modifications to
    those files except for ltmain.sh which recognizes the additional -S flag
    that INN's install-sh script uses.

    This install-sh script should also be updated at the same time from
    <https://git.savannah.gnu.org/cgit/automake.git/tree/>; it similarly
    contains a local modification mentioned in a comment at the beginning of
    the file.

    Finally, the m4/pkg.m4 macro should be updated from
    <https://gitlab.freedesktop.org/pkg-config/pkg-config/>.

Autobuilds

    Automatic build logs on several platforms are available at
    <http://usenet.trigofacile.com/autobuild/inn/>.

Documentation

    INN's documentation is currently somewhat in a state of flux.  Much of
    the documentation is still in the form of man pages written directly in
    nroff.  Some parts of the documentation have been rewritten in POD; that
    documentation can be found in doc/pod.  The canonical source for most of
    the text documentation, including README, INSTALL, NEWS, and this file,
    is also POD.

    If you're modifying some part of INN's documentation and see that it has
    a POD version in doc/pod, you should make the modifications to the POD
    source and then regenerate the derived files.  For a quick introduction
    to POD, see the perlpod(1) man page on your system (it should be
    installed if you have Perl installed).

    When writing new documentation, write in whatever format you care to; if
    necessary, we can always convert it to POD or whatever else we want to
    use.  Having the documentation exist in *some* form is more important
    than what language you write it in.  If you don't have a preference,
    however, we prefer new documentation to be in POD.

    If you use POD or regenerate POD documentation, please install something
    close to the latest versions of the POD processing utilities to avoid
    changes to the documentation depending on who generated it last.  You
    can find the latest version of the "podlators" distribution on CPAN
    (<https://metacpan.org/dist/podlators>).

    There are makefile rules in doc/pod/Makefile to build all of the
    documentation whose master form is POD; if you add additional
    documentation, please add a rule there as well.  Documentation should be
    generated by cd'ing to doc/pod and typing "make file" where "file" is
    the relative path to the documentation file.  This will get all of the
    various flags right for pod2text or pod2man.

Error Handling

    INN has a set of generic error handling routines that should be used as
    much as possible so that the same syntax can be used for reporting
    errors everywhere in INN.  The six basic functions are notice,
    sysnotice, warn, syswarn, die, and sysdie; notice prints or logs an
    informative message, warn prints or logs a warning, and die does the
    same and then exits the current program.  The sys* versions add a colon,
    a space, and the value of strerror(errno) to the end of the message, and
    should be used to report failing system calls.

    All of the actual error reporting is done via error handlers, and a
    program can register its own handlers in addition to or instead of the
    default one.  The default error handler (message_log_stderr) prints to
    stderr, prepending the value of message_program_name if it's set to
    something other than NULL.  Several other error handlers are available,
    particularly including ones that use syslog.  See include/inn/messages.h
    for all of the available options.

    There is a different set of error handlers for notice/sysnotice,
    warn/syswarn, and die/sysdie.  To set them, make calls like:

        message_handlers_warn(1, message_log_stderr);
        message_handlers_die(2, message_log_stderr, message_log_syslog_err);

    The first argument is the number of handlers, and the remaining
    arguments are pointers to functions taking an int (the length of the
    formatted message), a const char * (the format), a va_list (the
    arguments), and an int that's 0 if warn or die was called and equal to
    the value of errno if syswarn or sysdie was called.  The length of the
    formatted message is obtained by calling vsnprintf with the provided
    format and arguments, and therefore is reliable to use as the size of a
    buffer to malloc to hold the result of formatting the message provided
    that vsnprintf is used to format it (warning: the system vsprintf may
    produce more output under some circumstances, so always use vsnprintf).

    The error handler can do anything it wishes; each error handler is
    called in the sequence given.  Error handlers shouldn't call warn or die
    unless great caution is taken to prevent infinite recursion.  Also be
    aware that sysdie is called if malloc fails in xmalloc, so if the error
    handler needs to allocate memory, it must not use xmalloc or a related
    function to do so and it must not call die to report failure.  The
    default syslog handlers report memory allocation failure to stderr and
    exit.

    Finally, die and sysdie support an additional handler (the external
    variable message_fatal_cleanup) that's called immediate before exiting,
    takes no arguments, and returns an int which is used as the argument for
    exit.  It can do any necessary global cleanup, call abort instead to
    generate a core dump or the like.

    The advantage of using this system everywhere in INN is that library
    code can use notice, warn, and die to report messages and errors, and
    each calling program can set up the handlers as appropriate to make sure
    the errors go to the right place.  The default handler is fine for
    interactive programs; for programs that run from interactive scripts,
    adding something like:

        message_program_name = "program";

    to the beginning of main (where program is the name of the program) will
    make it easier to figure out which program the script calls is failing. 
    For programs that may also be called non-interactively, like rnews, one
    may want to set up handlers like:

        message_handlers_notice(2, message_log_stdout, message_log_syslog_info);
        message_handlers_warn(2, message_log_stderr, message_log_syslog_warning);
        message_handlers_die(2, message_log_stderr, message_log_syslog_err);

    Finally, for daemons and other non-interactive programs, one may want to
    do:

        message_handlers_notice(1, message_log_syslog_info);
        message_handlers_warn(1, message_log_syslog_warning);
        message_handlers_die(1, message_log_syslog_err);

    to report errors only via syslog.  (Note that if you use syslog error
    handlers, the program should call openlog first thing to make sure they
    are logged with the right facility.)

    For historical reasons, error messages that are fatal to the news
    subsystem are logged at the LOG_CRIT priority, and therefore die in innd
    should use message_log_syslog_crit.  This seems like priority inflation
    and may change in the future to message_log_syslog_err.

Test Suite

    The test suite for INN is located in the tests directory and is just
    getting started.  The test suite consists of a set of programs listed in
    tests/TESTS and the scaffolding in the runtests program.

    Adding new tests is very straightforward and very flexible.  Just write
    a program that tests some part of INN, put it in a directory under tests
    named after the part of INN it's testing, and have it output first a
    line containing the count of test cases in that file, and then for each
    test a line saying "ok n" or "not ok n" where "n" is the test case
    number.  (If a test is skipped for some reason, such as a test of an
    optional feature that wasn't compiled into INN, the test program should
    output "ok n # skip".)  Add any rules necessary to build the test to
    tests/Makefile (note that for simplicity it doesn't recurse into
    subdirectories) and make sure it creates an executable ending in .t. 
    Then add the name of the test to tests/TESTS, without the .t ending.

    For C tests, you probably want to use the functions in tests/tap/basic.c
    (prototypes in tests/tap/basic.h) to handle all of the output.  For
    shell script tests, tests/tap/libtap.sh contains helpful shell
    functions.  See the existing tests for some hints about how to write new
    tests, as well as the tests/README guide.

    One naming convention: to distinguish more easily between for example
    lib/error.c (the implementation) and tests/lib/error-t.c (the test
    suite), we add -t to the end of the test file names.  So
    tests/lib/error-t.c is the source that compiles into an executable
    tests/lib/error.t which is run by putting a line in tests/TESTS of just
    "lib/error".

    Note that tests don't have to be written in C; in fact, lib/xmalloc.t is
    just a shell script (that calls a supporting C program).  Tests can be
    written in shell or Perl (but other languages should be avoided because
    someone who wants to run the test suite may not have it) and just have
    to follow the above output conventions.

    Additions to the test suite, no matter how simple, are very welcome.

    Running the test suite is done with:

        make check

    A single test can be run with verbose ouput via:

        tests/runtests -o <name-of-test>

    Using runtests ensures that necessary environment variables are set up.

Makefiles

    All INN Makefiles include Makefile.global at the top level, and only
    that makefile is a configure substitution target.  This has the
    disadvantage that configure's normal support for building in a tree
    outside of the source tree doesn't work, but it has the significant
    advantage of making configure run much faster and allowing one to run
    "make" in any subdirectory and pick up all the definitions and settings
    from the top level configuration.

    All INN Makefiles should also set "$(top)" to be the path to the top of
    the build directory (usually relative).  This path is used to find
    various programs like fixscript and Libtool so that the same macros (set
    in Makefile.global) can be used all over INN.

    The format of INN's Makefiles is mostly standardized; the best examples
    of the format are probably frontends/Makefile and backends/Makefile, at
    least for directories with lots of separate programs.  The "ALL"
    variable holds all the files that should be generated, "EXTRA" those
    additional files that were generated by configure, and "SOURCES" the C
    source files for generating tag information.

    There are a set of standard installation commands defined in make
    variables by Makefile.global, and these should be used for all file
    installations.  See the comment blocks in Makefile.global.in for
    information on what commands are available and when they should be used.
    There are also variables set for each of the installation directories
    that INN uses, for use in building the list of installed paths to files.

    Each subdirectory makefile should have the targets "all" (the default),
    "clean", "clobber"/"distclean", "install", and "profiled".  The
    "profiled" target generates a profiling version of the programs
    (although this hasn't been tested much).  These rules should be present
    and empty in those directories where they don't apply.

    Be sure to test compiling with both static and dynamic libraries and
    make sure that all the Libtool support works correctly.  All linking
    steps, and the compile steps for all library source, should be done
    through "$(LIBCC)" and "$(LIBLD)" (which will be set as appropriate in
    Makefile.global).

Scripts

    INN comes with and installs a large number of different scripts, both
    Bourne shell and Perl, and also comes with support for Tcl scripts
    (although it doesn't come with any).  Shell variables containing both
    configure-time information and configuration information from inn.conf
    are set by the innshellvars support libraries, so the only
    system-specific configuration that should have to be done is fixing the
    right path to the interpreter and adding a line to load the appropriate
    innshellvars.

    support/fixscript, built by configure, does this.  It takes a .in file
    and generates the final script (removing the .in) by fixing the path to
    the interpreter on the first line and replacing the second line,
    whatever it is, with code to load the innshellvars appropriate for that
    interpreter.  (If invoked with -i, it just fixes the interpreter path.)

    Scripts should use innshellvars (via fixscript) to get the right path
    and the right variables whenever possible, rather than having configure
    substitute values in them.  Any values needed at run-time should instead
    be available from all of the different innshellvars.

    As for Perl, the "INN::Config" module has the same features as
    innshellvars.pl (only kept for compatibility reasons with old scripts
    not shipped with INN); however, it can be safely used with warnings on
    in Perl scripts.

    See the existing scripts for examples of how this is done.

Include Files

    Include files relevant to all of INN, or relevant to the two libraries
    built as part of INN (the utility libinn library and the libinnstorage
    library that contains all storage and overview functions) are found in
    the include directory; other include files relevant only to a portion of
    INN are found in the relevant directory.

    Practically all INN source files will start with:

        #include "portable/system.h"

    This header file includes config.h, which picks up all defines generated
    by autoconf and is necessary for types that may not be present on all
    systems (*uid_t*, *pid_t*, *size_t*, *uint32_t*, and the like).  It
    therefore should be included before any other headers that use those
    types, as well as to get general configuration information.  The
    config.h header also includes inn/macros.h, inn/options.h, inn/system.h
    and portable/stdbool.h which pick up additional support macros and
    compile-time configuration.

    Besides, portable/system.h also includes all of the following headers,
    portably:

       #include <inttypes.h>
       #include <limits.h>
       #include <stdarg.h>
       #include <stdbool.h>
       #include <stddef.h>
       #include <stdint.h>
       #include <stdio.h>
       #include <stdlib.h>
       #include <string.h>
       #include <strings.h>
       #include <sys/types.h>
       #include <unistd.h>

    except that it doesn't include headers that are missing on a given
    system, replaces functions not found on the system with the INN
    equivalents, provides macros that INN assumes are available but which
    weren't found, and defines some additional portability things.  Even if
    this is more headers than the source file actually needs, it's generally
    better to just include portable/system.h rather than trying to duplicate
    the autoconf-driven hackery that it does to do things portably.  The
    primary exception is for source files in lib that only define a single
    function and are used for portability; those may want to include only
    config.h so that they can be easily used in other projects that use
    autoconf.  config.h is a fairly standard header name for this purpose.

    There are portable wrappers around several header files that have known
    portability traps or that need some fixing up on some platforms.  Look
    in include/portable and familiarize yourself with them and use them
    where appropriate.

    Another frequently included header file is inn/libinn.h, which among
    other things defines xmalloc(), xrealloc(), xstrdup(), and xcalloc(),
    which are checked versions of the standard memory allocation routines
    that terminate the program if the memory allocation fails.  These should
    generally always be used instead of the regular C versions. 
    inn/libinn.h also provides various other utility functions that are
    frequently used.

    inn/paths.h includes a wide variety of paths determined at configure
    time, both default paths to various parts of INN and paths to programs. 
    Don't just use the default paths, though, if they're also configurable
    in inn.conf; instead, call innconf_read() and use the global *innconf*
    structure.

    Other files in include are interfaces to particular bits of INN library
    functionality or are used for other purposes; see the comments in each
    file.

    Eventually, the header files will be separated into installed header
    files and uninstalled header files; the latter are those headers that
    are used only for compiling INN and aren't useful for users of INN's
    libraries (such as innperl.h).  All of the installed headers will live
    in include/inn and be installed in a subdirectory named inn in the
    configured include directory.  This conversion is still in progress.

    When writing header files, remember that C reserves all identifiers
    beginning with two underscores and all identifiers beginning with an
    underscore and a capital letter for the use of the implementation; don't
    use any identifiers with names like that.  Additionally, any identifier
    beginning with an underscore and a lower-case letter is reserved in file
    scope, which means that such identifiers can only be used by INN for the
    name of structure members or function arguments in function prototypes.

    Try to pay attention to the impact of a header file on the program
    namespace, particularly for installed header files in include/inn.  All
    symbols defined by a header file should ideally begin with "INN_",
    "inn_", or some other unique prefix indicating the subsystem that symbol
    is part of, to avoid accidental conflicts with symbols defined by the
    program that uses that header file.

Libraries

    INN includes three shared libraries, in lib, storage, and history. 
    Whenever any of the source to those libraries is modified, the library
    version information must be updated at the top of the Makefile in that
    directory.  Follow the instructions in the Libtool manual under
    Versioning / Updating version info, with the exception that, contrary to
    point 2, it's useful to those running snapshots to update the version
    information more frequently than for each public release.  Remember that
    the version information has to be updated to allow recovery from a "make
    update" command.

Coding Style

    INN has quite a variety of coding styles intermixed.  As with all
    programs, it's preferable when making minor modifications to keep the
    coding style of the code you're modifying.  In INN, that will vary by
    file.  (Over time we're trying to standardize on one coding style, so
    changing the region you worked on to fit the general coding style is
    also acceptable).

    When modifying or writing new code in C, it should conform to the
    *Clang-format* style of the project.  Similarly, Perl, Python and shell
    scripts should conform to respectively the *perltidy*, *Black* and
    *shfmt* code styles of the project.  Just run "make reformat" at the top
    level of the source tree to properly reformat all files.  Additionally,
    the conformance of Perl scripts to some policies from *perlcritic* and
    *perltidy* should be checked by running "make code-check".

    If you're writing a substantial new piece of code, the prevailing
    "standard" INN coding style is the following:

    *  Write in regular ANSI C whenever possible.  Use the normal ANSI and
       POSIX constructs and use autoconf or portability wrappers to fix
       things up beforehand so that the code itself can read like regular
       ANSI or POSIX code.  Code should be written so that it works as
       expected on a modern platform and is fixed up with portability tricks
       for older platforms, not the other way around.  You may assume an
       ANSI C compiler.

       Try to use const wherever appropriate.  Don't use register; modern
       compilers will do as good of a job as you will in choosing what to
       put into a register.  Don't bother with restrict (at least yet).

    *  Use string handling functions that take counts for the size of the
       buffer whenever possible.  This means using snprintf in preference to
       sprintf and using strlcpy and strlcat in preference to strcpy and
       strcat.  Also, use strlcpy and strlcat instead of strncpy and
       strncat, as it is much easier to audit uses of the former than the
       latter.  strlcpy is like strncpy except that it always nul-terminates
       and doesn't fill the rest of the buffer with nuls, making it more
       efficient.  strlcat is like strncat except that it always
       nul-terminates and it takes the total size of the buffer as its third
       argument rather than just the amount of space left.  All of these
       functions are guaranteed to be available; there are replacements in
       lib for systems that don't have them.

       If you have to use a string copying routine that doesn't
       nul-terminate, use memcpy instead.  Avoid introducing any uses of
       strcpy, strcat, strncpy, or strncat so that we can use grep to find
       dangerous usages and switch them to better functions.

    *  Avoid "#ifdef" and friends whenever possible.  Particularly avoid
       using them in the middle of code blocks.  Try to hide all portability
       preprocessor magic in header files or in portability code in lib. 
       When something just has to be done two completely different ways
       depending on the platform or compile options or the like, try to
       abstract that functionality out into a generic function and provide
       two separate implementations using "#ifdef"; then the main code can
       just call that function.

       If you do have to use preprocessor defines, note that if you always
       define them to either 0 or 1 (never use "#define" without a second
       argument), you can use the preprocessor define in a regular if
       statement rather than using "#if" or "#ifdef".  Make use of this
       instead of "#ifdef" when possible, since that way the compiler will
       still syntax-check the other branch for you and it makes it far
       easier to convert the code to use a run-time check if necessary. 
       (Unfortunately, this trick can't be used if one branch may call
       functions unavailable on a particular platform.)

    *  Avoid uses of fixed-width buffers except in performance-critical
       code, as it's harder to be sure that such code is correct and it
       tends to be less flexible later on.  If you need a reusable,
       resizable memory buffer, one is provided in lib/buffer.c.

    *  Avoid uses of static variables whenever possible, particularly in
       libraries, because it interferes with making the code re-entrant down
       the road and makes it harder to follow what's going on.  Similarly,
       avoid using global variables whenever possible, and if they are
       required, try to wrap them into structures that could later be
       changed into arguments to the affected functions.

    *  Use a roughly BSD indentation style but with four-space indents. 
       This means no space before the parenthesis around function arguments,
       open brace on the same line as if/while/for, and close and open brace
       on the same line as else.

    *  Introductory comments for functions or files are generally written
       as:

           /*
           **  Introductory comment.
           */

       Other multiline comments in the source are generally written as:

           /* This is a
              multiline comment. */

       Comments before functions saying what they do are nice to have.

    *  Checks for NULL pointers are preferably written out explicitly; in
       other words, use:

           if (p != NULL)

       rather than:

           if (p)

       to make it clearer what the code is assuming.

    *  It's better to always put the body of an "if" statement on a separate
       line, even if it's only a single line.  In other words, write:

           if (p != NULL)
               return p;

       and not:

           if (p != NULL) return p;

       This is in part for a practical reason: some code coverage analysis
       tools like purecov will count the second example above as a single
       line and won't notice if the condition always evaluates the same way.

    *  Plain structs make perfectly reasonable abstract data types; it's not
       necessary to typedef the struct to something else.  Structs are
       actually very useful for opaque data structures, since you can
       predeclare them and then manipulate pointers to them without ever
       having to know what the contents look like.  Please try to avoid
       typedefs except for function pointers or other extremely confusing
       data types, or for data types where we really gain some significant
       data abstraction from hiding the underlying data type.  Also avoid
       using the "_t" suffix for any type; all types ending in "_t" are
       reserved by POSIX.  For typedefs of function pointer types, a suffix
       of "_func" usually works.

       This style point is currently widely violated inside of INN itself;
       INN originally made extensive use of typedefs.

    *  When noting something that should be improved later, add a comment
       containing "FIXME:" so that one can easily grep for such comments.

    For users of emacs cc-mode, use auto-formatting with clang-format and
    Black.

    Finally, if possible, please don't use tabs in source files, since they
    can expand differently in different environments.  In particular, please
    try not to use the mix of tabs and spaces that is the default in emacs. 
    If you use emacs to edit INN code, you may want to put:

        ; Use only spaces when indenting or centering, no tabs.
        (setq-default indent-tabs-mode nil)

    in your ~/.emacs file.

    Note that this is only a rough guideline and the maintainers aren't
    style nazis; we're more interested in your code contribution than in how
    you write it.

Making a Release

    This is a checklist that INN maintainers should go through when
    preparing a new release of INN.

    1.  Update the files shipped with INN, and that are maintained by
        external projects.

        * Make sure that support/config.guess, support/config.sub,
          support/install-sh, support/ltmain.sh, Libtool m4 files
          (libtool.m4, ltoptions.m4, ltsugar.m4, ltversion.m4 and
          lt~obsolete.m4) and m4/pkg.m4 are the latest versions.  See the
          instructions in "Configuring and Portability" for details on how
          to update these files.  When updating executable files, verify
          that the committed version is still executable.

        * Make sure that the latest upstream version of the C TAP Harness
          package is used for the test suite driver.  It is available at
          <https://www.eyrie.org/~eagle/software/c-tap-harness/>, and can be
          easily synchronized with the script support/getc-tap-harness; just
          run it, have a look at the resulting changes in INN source code
          and, if everything seems all right, commit these changes.

          Parts specific to INN should be kept during an update (especially
          sections relative to LIBTEST_NEW_FORMAT because the test suite has
          not yet been fully updated to use the new format of C TAP
          Harness).

        * Make sure that the latest upstream version of the files maintained
          in the rra-c-util package that INN uses are the ones shipped with
          the release.  These files are available at
          <https://www.eyrie.org/~eagle/software/rra-c-util/> and can be
          easily synchronized with the script support/getrra-c-util; just
          run it, have a look at the resulting changes in INN source code
          and, if everything seems all right, commit these changes.

        * Make sure that control/pgpverify.in is in sync with the master
          version at <https://downloads.isc.org/pub/pgpcontrol/>.

        * Make sure that samples/control.ctl and samples/nocem.ctl are in
          sync with the master version at
          <https://downloads.isc.org/pub/usenet/CONFIG/control.ctl> and
          <https://rosalind.home.xs4all.nl/nocemreg/nocemreg.html>.

    2.  Monitor changes carried on a few other projects.

        * Check whether patches from OpenSSL (apps/lib/s_cb.c,
          apps/s_server.c and crypto/bio/bio_dump.c at
          <https://github.com/openssl/openssl>) could be merged into
          nnrpd/tls.c, and new TLS versions could be supported in the
          tlsprotocols parameter in inn.conf.

        * Check whether recent LibreSSL releases have backported new
          functions from OpenSSL, that could then be enabled in nnrpd for
          LibreSSL, if that's not already the case.

    3.  Build INN (including the contrib and tests directories) with
        warnings on ("make warnings") and run the test suite ("make tests").
        Fix any errors.

        Several builds with different configure-time options should be
        tested, so as to be sure they work fine (especially
        --enable-shared=no, --enable-tagged-hash, --enable-keywords,
        --enable-largefiles and --enable-reduced-depends).

        Ideally, ensure INN builds fine with the latest versions of external
        libraries it has support for (Berkeley DB, blocklistd, Cyrus SASL,
        libcanlock, LibreSSL, MIT Kerberos v5, OpenSSL, Perl, Python,
        SQLite, zlib).

    4.  Configure INN with all the external libraries it supports, and run
        "make depend" to ensure dependencies are properly defined in all INN
        Makefiles.  Commit the changes, if appropriate.

    5.  Ensure that the source code is properly formatted with the latest
        versions of reformatting programs (run "make reformat") and does not
        violate some enforced rules (run "make code-check").

    6.  If possible, on a news server running the forthcoming release, run
        the following commands to make sure they do not produce any errors:

            cnfsstat -a -v
            ctlinnd checkfile
            inncheck -a --perm --pedantic
            ovdb_stat -klmMtv
            ovsqlite-util -A
            scanlogs norotate
            scanspool -n -v
            tdx-util -A

    7.  Maintain up-to-date information in various files.

        * Update INSTALL with the list of supported systems.

        * Update copyright years in LICENSE.  Ideally, all the files
          modified in this release should also have their copyright years
          updated accordingly, when present.

        * Proof-read and update doc/pod/news.pod.  Add the release date when
          generating the final release.

          Be more detailed for a minor release than for a major release. 
          For a major release, also add information on how to upgrade from
          the last major release, including anything special to be aware of.
          (Minor releases shouldn't require any special care when
          upgrading.)

        * Bump the revision number in doc/FAQ (subject 1.2) so that it could
          be included in a final release.  It should not be changed for a
          beta or a release candidate (the FAQ is indeed periodically posted
          to news.software.nntp from the GitHub directory, and should not
          mention unreleased versions).

          If making a major release, the revision numbers of the STABLE
          series should also be bumped in doc/FAQ at the end of subject 1.2.

        * Double-check for the final release that the library version
          information in history/Makefile, lib/Makefile, and
          storage/Makefile has been updated since the previous release. 
          Follow the rules given at
          <https://www.gnu.org/software/libtool/manual/html_node/Updating-ve
          rsion-info.html>.  The commit message usually contains a brief
          description of API changes, if any, just for the record.  Avoid
          bumping SONAME in minor releases (ideally, changes in any
          interfaces should be delayed until the next major release, and the
          bump clearly mentioned in the releases notes).

    8.  If making a major release, create a new branch in Git named after
        the major release.  This branch will be used for minor releases
        based on that major release and can be done a little while before
        the .0 release of that major release.

            git checkout -b Y.Y
            git push --set-upstream origin Y.Y

        Then, in that newly created branch, adapt the first paragraph of
        readme.pod, remove its second paragraph which deals with development
        versions, and update the URLs to point to the documentation of the
        new stable version.

    9.  Check out a copy of the release branch, and perform the following
        actions.

        * Run "autogen" and "configure" that are currently necessary to
          generate Makefile.global.

        * Then, run "make warnings" to generate all necessary files.

        * Afterwards, run "make check-manifest".  There shouldn't be any
          differences; otherwise, fix the MANIFEST file.

    10. Run "make release" for a final release, "support/mksnapshot BETA b1"
        for the first beta version of a new release, or "support/mksnapshot
        RC rc1" for the first release candidate version of a new release.

    11. Only on the branch where the release is done, modify the
        "VERSION_EXTRA" variable in Makefile.global.in so that the
        "prerelease" value does not appear in the upcoming Git tag.

        When making the final release, this variable should be empty.  For a
        testing release, it should reflect the version name used in the
        "make release" command (like "rc1 version").

    12. Create an annotated signed tag corresponding to the contents of the
        tarball, using a PGP key declared in the committer's GitHub profile:

            git tag Y.Y.Y <commit-hash> -s -m "INN Y.Y.Y release tag"
            git push origin Y.Y.Y

        Check that it appears as "Verified" in the GitHub interface.

    13. Re-add the "prerelease" value to the "VERSION_EXTRA" variable in
        Makefile.global.in.

    14. Publish a release in GitHub, based on that tag.  For a testing
        release, tick the box corresponding to a pre-release.

        Include the description from NEWS, and attach the tarball.  The
        description should be modelled on what was done for previous
        releases.

        When publishing the final release, empty the now redundant
        description of the pre-release, and just refer to the final release.

    15. For a testing release, announce its availability in inn-workers,
        along with a draft of the release announcement for proof-reading. 
        Install the testing release on at least one system and make sure
        that system runs fine for at least a few days.

        That's all for a testing release. The following steps only concern
        final releases.

    16. Bump revision numbers to reflect the one of the following release,
        especially in doc/pod/install.pod and readme.pod for major releases,
        configure.ac and Makefile.global.in for both minor and major
        releases.  (It is not necessary to bump the revision number if the
        release is supposed to be the last one in a branch.)

    17. Update milestones in the GitHub bug tracker to reflect the new
        release.

    18. Make the previously generated release tar file available into the
        public area of "downloads.isc.org".  Sign the release, creating a
        .asc file, using:

            gpg --detach-sign --armor inn-Y.Y.Y.tar.gz

        Update the inn.tar.gz* links and possibly move older releases off
        into the OLD directory.

        (Currently, this is all done by Russ by updating the files in
        <https://archives.eyrie.org/software/inn/> and then letting ISC
        automatically mirror them via rsync within a day.  The ISC web site
        does not need being updated as it does not directly link to the
        release, nor mention the version of the last release.  Just check
        the information at <https://www.isc.org/othersoftware/#INN> is still
        available and accurate, though.)

    19. Now that the signature of the release has been generated, attach it
        to the GitHub release.

    20. After "downloads.isc.org" has correctly mirrored the release, send
        an announce on inn-announce and in news.software.nntp (with a
        possible crosspost to news.admin.announce).

    21. Ping Russ to clean up the snapshots generated for the previous
        version and, for major releases, update the branch used for the
        generation of STABLE snapshots.

    22. Ping Russ to update <https://www.eyrie.org/~eagle/software/inn/>
        with the latest version information and, for a major release, clone
        the documentation tree for CURRENT as a new stable documentation
        tree for the stable release series.

        Also ensure the URL redirection of the docs-Y.Y subdirectory
        corresponding to the next major release points to docs.

References

    Some additional references that may be hard to find and may be of use to
    people working on INN:

    <https://www.eyrie.org/~eagle/nntp/>
        The home page for the IETF NNTP standardization effort, including
        links to the IETF NNTP working group archives and copies of the
        latest drafts of the new NNTP standard.  The old archived mailing
        list traffic contains a lot of interesting discussion of why NNTP is
        the way it is.

    <https://www.eyrie.org/~eagle/usefor/>
        A collection of documents about the Usenet article format, including
        most of the relevant RFCs and Internet-Drafts.

    <https://mailarchive.ietf.org/arch/browse/usefor/>
        The archives for the USEFOR IETF working group, the working group
        for the RFC 1036 replacement (the format of Usenet articles), now
        published as RFC 5536 and RFC 5537.

    <http://www.mibsoftware.com/userkt/userkt.html>
        Forrest Cavalier provides several tools related to earlier versions
        of INN (2.0 to 2.3.x).  His web site is a great source of
        information about Usenet in general.

    <http://tools.ietf.org/html/draft-lutchann-ipv6-intro-00>
        A primer on IPv6 with pointers to the appropriate places for more
        technical details as needed, useful when working on IPv6 support in
        INN.

