AnyEvent/MCP/Config.pm

=head1 NAME

AnyEvent::MCP::Config - named servers and derived MCP credentials

=head1 SYNOPSIS

   use AnyEvent::MCP::Config;

   my $config = AnyEvent::MCP::Config->global;
   my $token = $config->credential ("token", "agni");
   my $url = $config->http_url ("agni", undef, path => "/");

=head1 DESCRIPTION

An MCP server and its clients often need matching credentials. Rather than
maintaining a separate password for each server and user, this module can
derive them from one private master secret. The invoked program basename,
instance name, optional username and credential purpose each contribute to
the result. Instances default to C<default>; different programs still derive
different credentials for that instance name.

The shared file format is described in L<AnyEvent::MCP/GLOBAL CONFIGURATION>.
Loading this module does not read any files. The first call to C<global>
reads the configuration, ensures a master secret exists and caches the object
for the process.

A missing secret is generated using C<AnyEvent::MCP::random_bytes> and saved
when possible. Saving failure produces a warning; the generated secret remains
usable in this process, but another process might derive different credentials.
A supplied invalid secret is an error. Changing or losing the master secret
invalidates all credentials derived from it.

Derivation uses C<derive_secret> with the random master key.
The application namespace, purpose, program, instance name and username are
separately length-prefixed, so distinct contexts derive different credentials.
Deriving a password does not create an account or configure the server to
accept it: authentication still belongs to the server.

=head1 METHODS

=over

=item $config = AnyEvent::MCP::Config->global (file => $file)

Returns the cached global configuration. The first call accepts the same
arguments as C<new>; later calls return the same object without rereading
the file. Call this explicitly during program startup.

=item $config = AnyEvent::MCP::Config->new (file => $file)

Reads C<$file>, or the default file when omitted, and ensures a master
secret exists. Unlike C<global>, each call creates an independent object.
A missing file is allowed; other read errors are fatal. Sections are available
as C<< $config->{section}{$section} >>, each a hash reference of string
values. Named servers use C<[instance NAME]>.

=item $config = AnyEvent::MCP::Config->init (file => $file)

Explicitly creates the configuration file with a random secret, mode 0600.
Creates missing parent directories with mode 0700. Fails if the file already
exists, so it cannot accidentally replace an existing secret.

=item $bytes = $config->derive_secret ($length, @info)

=item $bytes = AnyEvent::MCP::Config->derive_secret ($length, @info)

Derive C<$length> secret bytes from the configuration's master secret and
an ordered list of context byte strings C<@info>. The class form uses
C<global>, loading the default configuration on first use and reusing it
thereafter. The object form uses that object's configuration, including
one loaded from an explicit file.

The same master secret and context always produce the same bytes. Use a
distinctive application/purpose string as the first context field, followed
by names or other values identifying the result:

   my $secret = AnyEvent::MCP::Config->derive_secret (
      32, "my application token v1", AnyEvent::MCP::utf8enc ($name)
   );

The result contains raw bytes; encode it yourself if a printable token is
needed. This method does not add the result to a server's accepted tokens.

The fixed C<anyevent-mcp> context field is prepended automatically.
Context fields are separately length-prefixed, so C<("ab", "c")> and
C<("a", "bc")> have different contexts. Encode character strings explicitly,
for example with C<AnyEvent::MCP::utf8enc>. Context arguments are left
unchanged.

C<$length> must be an integer in 0..16320; zero returns an empty string.
Shorter results are prefixes of longer results for the same master secret
and context. Use distinct context fields for different purposes, rather
than relying on different lengths to separate them.

Derivation uses HKDF-SHA512 expansion, with each context field prefixed by
its four-byte big-endian byte length. Changing or losing the master secret
changes every result derived from it.

=item $credential = $config->credential ($purpose, $name, $username)

Derives a 32-byte credential, returned as unpadded URL-safe Base64.
C<$purpose> is C<token>. C<$name> is the instance name, and C<$username>
is optional. The default server credential is derived with no username.

Credentials use the context C<("anyevent-mcp", "token", PROGRAM, NAME, USER)>.
PROGRAM is the invoked basename, with a trailing C<.pl> or C<.perl> removed.
Changing the program or instance name changes the credential. This derivation
replaces the older name-only context; update stored client URLs.
A credential derived with C<$username> is B<not> automatically accepted
by the server. This method neither requires a server section nor configures
authentication.

=item $program = AnyEvent::MCP::Config::program_name ()

Returns the invoked program basename, stripping C<.pl> or C<.perl>.
An inline Perl invocation uses C<perl>. This identity also selects the
C<[program PROGRAM]> configuration section; it is independent of routing aliases.

=item $name = AnyEvent::MCP::Config::server_name ($name)

Validate a service-instance name, or use C<default> if undefined.
Names consist of an ASCII letter or underscore followed by letters, digits,
underscores or hyphens.

=item @options = AnyEvent::MCP::Config::http_getopt (\$name, \$bind, \$print_url, \@tokens)

Return standard C<Getopt::Long> options referring to the caller's scalars.

=item $port = $config->server_port ($name)

Derive a stable default port in 16384..32767 from the master secret and
program basename and service-instance name. Collisions produce ordinary listener bind errors.

=item %settings = $config->http_settings ($name, $bind)

Resolve HTTP settings from C<[instance NAME]> and an optional command-line
C<bind> override. The default is IPv4 loopback and the name-derived port.
The bind setting accepts C<ADDRESS:PORT>, C<[IPv6]:PORT>, C<ADDRESS>,
and C<:PORT> (which keeps the default loopback address).
Hostnames are resolved once when settings are obtained; their original
spelling is advertised unless C<url_host> overrides it. The returned options
include C<name>, C<host>, C<port> and C<tokens>, plus configured C<path>,
C<url_host> and C<url_scheme>. This does not start a listener.

=item @rules = $config->auto_rules ($name)

Return ordered automatic permission rules from C<[program PROGRAM]> and
C<[instance NAME]>. C<auto-rule.SUFFIX = allow|deny TOOL[,ACTION[,CAPABILITY]]>
entries are sorted by key. The suffix is an arbitrary ordering label; instance
entries override matching program entries, and an empty value disables an
inherited entry. Command-line rules take precedence over these defaults.

=item $url = $config->http_url ($name, $bind, %options)

Format a URL containing the first accepted token, without listening.
Port zero cannot be used because the kernel has not yet selected a port.
When the token is derived, the master secret must be persistently stored,
so the next process derives the same URL. Explicit static tokens and
C<auth =E<gt> "none"> do not require that persistence check.

=back

=cut

package AnyEvent::MCP::Config;

use common::sense;
use AnyEvent::MCP ();
use Digest::SHA ();
use MIME::Base64 ();
use File::Basename ();
use File::Path ();
use Fcntl qw(O_WRONLY O_RDWR O_CREAT O_EXCL LOCK_EX);
use Errno qw(ENOENT);
use AnyEvent::Socket ();
use Socket ();

our @ISA = qw(AnyEvent::MCP::Base);

sub _file {
   my $dir = $ENV{XDG_CONFIG_HOME}
      || ($ENV{HOME} || die "HOME is not set\n") . "/.config";

   "$dir/anyevent-mcp/global.ini"
}

my $global;

sub global {
   my $class = shift;

   $global ||= $class->new (@_)
}

sub new {
   my ($class, %kv) = @_;

   my $self = $class->SUPER::new (section => {}, %kv);
   $self->{file} = _file unless exists $self->{file};

   if (open my $fh, "<:encoding(UTF-8)", $self->{file}) {
      $self->_read ($fh);
      close $fh or die "$self->{file}: $!\n";
   } else {
      die "$self->{file}: $!\n" unless $! == ENOENT;
   }

   $self->_ensure_secret;

   $self->{section}{global}{secret} =~ /\A[0-9a-fA-F]{128}\z/
      or die "$self->{file}: invalid secret; supply 128 hexadecimal digits\n";

   $self
}

sub _read {
   my ($self, $fh) = @_;

   my @stat = stat $fh;
   die "$self->{file}: configuration must be private and owned by this user\n"
      if $stat[4] != $< || $stat[2] & 077;

   local $/;
   AnyEvent::MCP::parse_ini scalar (<$fh>), sub {
      my ($name, $kv) = @_;
      my $section = $self->{section}{$name || "global"} ||= {};
      %$section = (%$section, %$kv);
   }, $self->{file};

}

sub _ensure_secret {
   my ($self) = @_;

   return if exists $self->{section}{global}{secret};

   my $secret = eval { unpack "H*", AnyEvent::MCP::random_bytes 64 };
   die "$@Supply a securely generated 128-digit hexadecimal secret in $self->{file}\n"
      if $@;

   eval {
      File::Path::mkpath (File::Basename::dirname ($self->{file}), 0, 0700);
      sysopen my $fh, $self->{file}, O_RDWR | O_CREAT, 0600
         or die "$self->{file}: $!\n";
      flock $fh, LOCK_EX or die "$self->{file}: $!\n";
      binmode $fh, ":encoding(UTF-8)";

      my $disk = bless { file => $self->{file}, section => {} }, ref $self;
      $disk->_read ($fh);

      unless (exists $disk->{section}{global}{secret}) {
         seek $fh, 0, 2 or die "$self->{file}: $!\n";
         print {$fh} "\n[global]\nsecret = $secret\n"
            or die "$self->{file}: $!\n";
         $disk->{section}{global}{secret} = $secret;
      }

      close $fh or die "$self->{file}: $!\n";
      $self->{section} = $disk->{section};
      1
   } or warn "Cannot save MCP master secret; credentials may only be stable for this process: $@";

   $self->{section}{global}{secret} = $secret
      unless exists $self->{section}{global}{secret};
}

sub init {
   my ($class, %kv) = @_;

   my $file = exists $kv{file} ? $kv{file} : _file;

   my $secret = AnyEvent::MCP::random_bytes 64;

   File::Path::mkpath (File::Basename::dirname ($file), 0, 0700);

   sysopen my $fh, $file, O_WRONLY | O_CREAT | O_EXCL, 0600
      or die "$file: $!\n";

   print {$fh} "[global]\nsecret = ", unpack ("H*", $secret), "\n"
      or die "$file: $!\n";
   close $fh or die "$file: $!\n";

   $class->new (file => $file)
}

sub _prk_derive_secret($$@) {
   my ($prk, $length, @info) = @_;

   64 == length $prk
      or die "derive_secret: key length must be 64 octets\n";
   $length =~ /\A[0-9]+\z/ && $length <= 255 * 64
      or die "derive_secret: length must be an integer in 0..16320\n";

   my $info = pack "(N/a*)*", "anyevent-mcp", @info;
   my $t   = "";
   my $okm = "";
   my $i   = 0;

   while ($length > length $okm) {
      $t = Digest::SHA::hmac_sha512 $t . $info . chr ++$i, $prk;
      $okm .= $t;
   }

   substr $okm, 0, $length
}

sub derive_secret {
   my ($self, $length, @info) = @_;

   $self = $self->global unless ref $self;

   my $secret = $self->{section}{global}{secret};
   $secret =~ /\A[0-9a-fA-F]{128}\z/
      or die "$self->{file}: missing or invalid secret\n";

   _prk_derive_secret (pack ("H*", $secret), $length, @info)
}

sub credential {
   my ($self, $purpose, $name, $username) = @_;

   $username = "" unless defined $username;

   $purpose eq "token"
      or die "Unknown credential purpose '$purpose'\n";

   my $credential = MIME::Base64::encode_base64 (
      $self->derive_secret (
         32, $purpose, AnyEvent::MCP::utf8enc (program_name ()),
         AnyEvent::MCP::utf8enc ($name), AnyEvent::MCP::utf8enc ($username)
      ), ""
   );
   $credential =~ y!+/=!-_!d;

   $credential
}

sub program_name {
   my $name = File::Basename::basename ($0);
   $name =~ s/\.(?:pl|perl)\z//;
   $name eq "-e" ? "perl" : $name
}

sub server_name {
   my ($name) = @_;

   $name = "default" unless defined $name;

   $name =~ /\A[A-Za-z_][A-Za-z0-9_-]*\z/
      or die "Invalid MCP server name '$name'\n";

   $name
}

sub http_getopt {
   my ($name, $bind, $print_url, $tokens) = @_;

   "name=s" => $name, "bind=s" => $bind, "print-url" => $print_url, "token=s@" => $tokens
}

sub auto_rules {
   my ($self, $name) = @_;
   my %settings = (
      %{$self->{section}{"program " . program_name ()} || {}},
      %{$self->{section}{"instance " . server_name ($name)} || {}},
   );
   my @rules;

   for my $key (sort grep /\Aauto-rule\./, keys %settings) {
      $key =~ /\Aauto-rule\.(.+)\z/
         or die "Invalid automatic permission rule key '$key'\n";
      my $value = $settings{$key};
      next unless length $value;
      my ($decision, $spec) = $value =~ /\A(allow|deny)\s+(\S+)\z/
         or die "Invalid configured automatic permission rule '$key'\n";
      push @rules, [$decision, $spec];
   }

   @rules
}

sub server_port {
   my ($self, $name) = @_;

   $name = server_name $name;

   16384 + ((unpack "n", $self->derive_secret (2, "port", AnyEvent::MCP::utf8enc (program_name ()), AnyEvent::MCP::utf8enc ($name))) & 16383)
}

sub http_settings {
   my ($self, $name, $bind) = @_;

   $name = server_name $name;
   my $settings = {
      %{ $self->{section}{"program " . program_name ()} },
      %{ $self->{section}{"instance $name"} },
   };
   my $port = $self->server_port ($name);
   my $configured = $settings->{bind} // "127.0.0.1:$port";
   $configured = "127.0.0.1$configured" if $configured =~ /\A:[0-9]+\z/;
   my ($configured_host, $configured_port) = AnyEvent::Socket::parse_hostport $configured, $port;
   defined $configured_host && defined $configured_port
      && $configured_port =~ /\A[0-9]+\z/ && $configured_port <= 65535
      or die "Invalid MCP bind address '$configured'\n";

   $bind = $configured unless defined $bind;
   $bind = "127.0.0.1$bind" if $bind =~ /\A:[0-9]+\z/;

   my ($host, $service) = AnyEvent::Socket::parse_hostport $bind, $configured_port;
   defined $host && defined $service && $service =~ /\A[0-9]+\z/ && $service <= 65535
      or die "Invalid MCP bind address '$bind'\n";

   my %kv = (
      (map { exists $settings->{$_} ? ($_ => $settings->{$_}) : () }
         qw(path url_host url_scheme)),
      name => $name,
      host => $host,
      port => $service,
   );

   unless (AnyEvent::Socket::parse_address $host) {
      my ($error, @addresses) = Socket::getaddrinfo ($host, undef, { socktype => Socket::SOCK_STREAM () });
      !$error && @addresses
         or die "Cannot resolve MCP bind host '$host': $error\n";

      my (undef, $address) = AnyEvent::Socket::unpack_sockaddr $addresses[0]{addr};

      $kv{url_host} //= $host;
      $kv{host} = AnyEvent::Socket::format_address $address;
   }

   $kv{tokens} = [exists $settings->{tokens}
      ? split /\s*,\s*/, $settings->{tokens}, -1
      : $self->credential ("token", $name)];

   %kv
}

sub http_url {
   my ($self, $name, $bind, %options) = @_;

   $name = server_name $name;

   # only a derived token depends on the master secret surviving this process.
   if (($options{auth} || "") ne "none"
      && !exists $options{tokens}
      && !exists $self->{section}{"instance $name"}{tokens}
      && !exists $self->{section}{"program " . program_name ()}{tokens}) {
      my $stored = ref ($self)->new (file => $self->{file});
      $stored->{section}{global}{secret} eq $self->{section}{global}{secret}
         or die "MCP master secret is not persistently stored in $self->{file}\n";
   }

   require AnyEvent::MCP::Server::HTTP;
   my %http = $self->http_settings ($name, $bind);
   delete $http{tokens} if ($options{auth} || "") eq "none";

   AnyEvent::MCP::Server::HTTP->new (%http, %options)->url
}


1
Revision:	1.17
Committed:	Mon Oct 19 16:42:29 2026 UTC (3 weeks, 5 days ago) by root
Branch:	MAIN
Changes since 1.16:	+29 -0 lines
Log Message:	* empty log message *
#	User	Rev	Content
1	root	1.1	=head1 NAME
2
3			AnyEvent::MCP::Config - named servers and derived MCP credentials
4
5			=head1 SYNOPSIS
6
7	root	1.12	use AnyEvent::MCP::Config;
8
9	root	1.1	my $config = AnyEvent::MCP::Config->global;
10	root	1.8	my $token = $config->credential ("token", "agni");
11	root	1.6	my $url = $config->http_url ("agni", undef, path => "/");
12	root	1.1
13			=head1 DESCRIPTION
14
15	root	1.3	An MCP server and its clients often need matching credentials. Rather than
16			maintaining a separate password for each server and user, this module can
17	root	1.14	derive them from one private master secret. The invoked program basename,
18			instance name, optional username and credential purpose each contribute to
19			the result. Instances default to C<default>; different programs still derive
20			different credentials for that instance name.
21	root	1.3
22			The shared file format is described in L<AnyEvent::MCP/GLOBAL CONFIGURATION>.
23			Loading this module does not read any files. The first call to C<global>
24			reads the configuration, ensures a master secret exists and caches the object
25			for the process.
26	root	1.1
27			A missing secret is generated using C<AnyEvent::MCP::random_bytes> and saved
28			when possible. Saving failure produces a warning; the generated secret remains
29	root	1.3	usable in this process, but another process might derive different credentials.
30			A supplied invalid secret is an error. Changing or losing the master secret
31			invalidates all credentials derived from it.
32	root	1.1
33	root	1.13	Derivation uses C<derive_secret> with the random master key.
34	root	1.14	The application namespace, purpose, program, instance name and username are
35			separately length-prefixed, so distinct contexts derive different credentials.
36	root	1.3	Deriving a password does not create an account or configure the server to
37			accept it: authentication still belongs to the server.
38	root	1.1
39			=head1 METHODS
40
41	root	1.12	=over
42
43			=item $config = AnyEvent::MCP::Config->global (file => $file)
44	root	1.1
45			Returns the cached global configuration. The first call accepts the same
46			arguments as C<new>; later calls return the same object without rereading
47			the file. Call this explicitly during program startup.
48
49	root	1.12	=item $config = AnyEvent::MCP::Config->new (file => $file)
50	root	1.1
51			Reads C<$file>, or the default file when omitted, and ensures a master
52			secret exists. Unlike C<global>, each call creates an independent object.
53			A missing file is allowed; other read errors are fatal. Sections are available
54			as C<< $config->{section}{$section} >>, each a hash reference of string
55	root	1.10	values. Named servers use C<[instance NAME]>.
56	root	1.1
57	root	1.12	=item $config = AnyEvent::MCP::Config->init (file => $file)
58	root	1.1
59			Explicitly creates the configuration file with a random secret, mode 0600.
60			Creates missing parent directories with mode 0700. Fails if the file already
61			exists, so it cannot accidentally replace an existing secret.
62
63	root	1.13	=item $bytes = $config->derive_secret ($length, @info)
64
65			=item $bytes = AnyEvent::MCP::Config->derive_secret ($length, @info)
66
67			Derive C<$length> secret bytes from the configuration's master secret and
68			an ordered list of context byte strings C<@info>. The class form uses
69			C<global>, loading the default configuration on first use and reusing it
70			thereafter. The object form uses that object's configuration, including
71			one loaded from an explicit file.
72
73			The same master secret and context always produce the same bytes. Use a
74			distinctive application/purpose string as the first context field, followed
75			by names or other values identifying the result:
76
77			my $secret = AnyEvent::MCP::Config->derive_secret (
78			32, "my application token v1", AnyEvent::MCP::utf8enc ($name)
79			);
80
81			The result contains raw bytes; encode it yourself if a printable token is
82			needed. This method does not add the result to a server's accepted tokens.
83
84	root	1.14	The fixed C<anyevent-mcp> context field is prepended automatically.
85	root	1.13	Context fields are separately length-prefixed, so C<("ab", "c")> and
86			C<("a", "bc")> have different contexts. Encode character strings explicitly,
87			for example with C<AnyEvent::MCP::utf8enc>. Context arguments are left
88			unchanged.
89
90			C<$length> must be an integer in 0..16320; zero returns an empty string.
91			Shorter results are prefixes of longer results for the same master secret
92			and context. Use distinct context fields for different purposes, rather
93			than relying on different lengths to separate them.
94
95			Derivation uses HKDF-SHA512 expansion, with each context field prefixed by
96			its four-byte big-endian byte length. Changing or losing the master secret
97			changes every result derived from it.
98
99	root	1.12	=item $credential = $config->credential ($purpose, $name, $username)
100	root	1.1
101			Derives a 32-byte credential, returned as unpadded URL-safe Base64.
102	root	1.14	C<$purpose> is C<token>. C<$name> is the instance name, and C<$username>
103	root	1.8	is optional. The default server credential is derived with no username.
104	root	1.1
105	root	1.14	Credentials use the context C<("anyevent-mcp", "token", PROGRAM, NAME, USER)>.
106			PROGRAM is the invoked basename, with a trailing C<.pl> or C<.perl> removed.
107			Changing the program or instance name changes the credential. This derivation
108			replaces the older name-only context; update stored client URLs.
109	root	1.12	A credential derived with C<$username> is B<not> automatically accepted
110			by the server. This method neither requires a server section nor configures
111			authentication.
112	root	1.1
113	root	1.14	=item $program = AnyEvent::MCP::Config::program_name ()
114
115			Returns the invoked program basename, stripping C<.pl> or C<.perl>.
116			An inline Perl invocation uses C<perl>. This identity also selects the
117			C<[program PROGRAM]> configuration section; it is independent of routing aliases.
118
119	root	1.12	=item $name = AnyEvent::MCP::Config::server_name ($name)
120	root	1.4
121	root	1.14	Validate a service-instance name, or use C<default> if undefined.
122	root	1.4	Names consist of an ASCII letter or underscore followed by letters, digits,
123			underscores or hyphens.
124
125	root	1.12	=item @options = AnyEvent::MCP::Config::http_getopt (\$name, \$bind, \$print_url, \@tokens)
126	root	1.4
127			Return standard C<Getopt::Long> options referring to the caller's scalars.
128
129	root	1.12	=item $port = $config->server_port ($name)
130	root	1.4
131			Derive a stable default port in 16384..32767 from the master secret and
132	root	1.14	program basename and service-instance name. Collisions produce ordinary listener bind errors.
133	root	1.4
134	root	1.12	=item %settings = $config->http_settings ($name, $bind)
135	root	1.4
136	root	1.10	Resolve HTTP settings from C<[instance NAME]> and an optional command-line
137	root	1.4	C<bind> override. The default is IPv4 loopback and the name-derived port.
138			The bind setting accepts C<ADDRESS:PORT>, C<[IPv6]:PORT>, C<ADDRESS>,
139			and C<:PORT> (which keeps the default loopback address).
140	root	1.12	Hostnames are resolved once when settings are obtained; their original
141			spelling is advertised unless C<url_host> overrides it. The returned options
142			include C<name>, C<host>, C<port> and C<tokens>, plus configured C<path>,
143			C<url_host> and C<url_scheme>. This does not start a listener.
144	root	1.4
145	root	1.17	=item @rules = $config->auto_rules ($name)
146
147			Return ordered automatic permission rules from C<[program PROGRAM]> and
148			C<[instance NAME]>. C<auto-rule.SUFFIX = allow\|deny TOOL[,ACTION[,CAPABILITY]]>
149			entries are sorted by key. The suffix is an arbitrary ordering label; instance
150			entries override matching program entries, and an empty value disables an
151			inherited entry. Command-line rules take precedence over these defaults.
152
153	root	1.12	=item $url = $config->http_url ($name, $bind, %options)
154	root	1.4
155	root	1.8	Format a URL containing the first accepted token, without listening.
156			Port zero cannot be used because the kernel has not yet selected a port.
157			When the token is derived, the master secret must be persistently stored,
158			so the next process derives the same URL. Explicit static tokens and
159			C<auth =E<gt> "none"> do not require that persistence check.
160	root	1.4
161	root	1.12	=back
162
163	root	1.1	=cut
164
165			package AnyEvent::MCP::Config;
166
167			use common::sense;
168			use AnyEvent::MCP ();
169	root	1.13	use Digest::SHA ();
170	root	1.1	use MIME::Base64 ();
171			use File::Basename ();
172			use File::Path ();
173			use Fcntl qw(O_WRONLY O_RDWR O_CREAT O_EXCL LOCK_EX);
174			use Errno qw(ENOENT);
175	root	1.4	use AnyEvent::Socket ();
176			use Socket ();
177	root	1.1
178			our @ISA = qw(AnyEvent::MCP::Base);
179
180			sub _file {
181			my $dir = $ENV{XDG_CONFIG_HOME}
182			\|\| ($ENV{HOME} \|\| die "HOME is not set\n") . "/.config";
183
184			"$dir/anyevent-mcp/global.ini"
185			}
186
187			my $global;
188
189			sub global {
190			my $class = shift;
191
192			$global \|\|= $class->new (@_)
193			}
194
195	root	1.16	sub new {
196	root	1.1	my ($class, %kv) = @_;
197	root	1.11
198	root	1.1	my $self = $class->SUPER::new (section => {}, %kv);
199			$self->{file} = _file unless exists $self->{file};
200
201			if (open my $fh, "<:encoding(UTF-8)", $self->{file}) {
202			$self->_read ($fh);
203			close $fh or die "$self->{file}: $!\n";
204			} else {
205			die "$self->{file}: $!\n" unless $! == ENOENT;
206			}
207
208			$self->_ensure_secret;
209
210	root	1.11	$self->{section}{global}{secret} =~ /\A[0-9a-fA-F]{128}\z/
211			or die "$self->{file}: invalid secret; supply 128 hexadecimal digits\n";
212	root	1.1
213			$self
214			}
215
216			sub _read {
217			my ($self, $fh) = @_;
218
219			my @stat = stat $fh;
220			die "$self->{file}: configuration must be private and owned by this user\n"
221			if $stat[4] != $< \|\| $stat[2] & 077;
222
223	root	1.15	local $/;
224			AnyEvent::MCP::parse_ini scalar (<$fh>), sub {
225			my ($name, $kv) = @_;
226			my $section = $self->{section}{$name \|\| "global"} \|\|= {};
227			%$section = (%$section, %$kv);
228			}, $self->{file};
229	root	1.1
230			}
231
232			sub _ensure_secret {
233			my ($self) = @_;
234
235			return if exists $self->{section}{global}{secret};
236
237			my $secret = eval { unpack "H*", AnyEvent::MCP::random_bytes 64 };
238			die "$@Supply a securely generated 128-digit hexadecimal secret in $self->{file}\n"
239			if $@;
240
241			eval {
242			File::Path::mkpath (File::Basename::dirname ($self->{file}), 0, 0700);
243			sysopen my $fh, $self->{file}, O_RDWR \| O_CREAT, 0600
244			or die "$self->{file}: $!\n";
245			flock $fh, LOCK_EX or die "$self->{file}: $!\n";
246			binmode $fh, ":encoding(UTF-8)";
247
248			my $disk = bless { file => $self->{file}, section => {} }, ref $self;
249			$disk->_read ($fh);
250
251			unless (exists $disk->{section}{global}{secret}) {
252			seek $fh, 0, 2 or die "$self->{file}: $!\n";
253			print {$fh} "\n[global]\nsecret = $secret\n"
254			or die "$self->{file}: $!\n";
255			$disk->{section}{global}{secret} = $secret;
256			}
257
258			close $fh or die "$self->{file}: $!\n";
259			$self->{section} = $disk->{section};
260			1
261			} or warn "Cannot save MCP master secret; credentials may only be stable for this process: $@";
262
263			$self->{section}{global}{secret} = $secret
264			unless exists $self->{section}{global}{secret};
265			}
266
267			sub init {
268			my ($class, %kv) = @_;
269	root	1.11
270	root	1.1	my $file = exists $kv{file} ? $kv{file} : _file;
271
272			my $secret = AnyEvent::MCP::random_bytes 64;
273
274			File::Path::mkpath (File::Basename::dirname ($file), 0, 0700);
275
276			sysopen my $fh, $file, O_WRONLY \| O_CREAT \| O_EXCL, 0600
277			or die "$file: $!\n";
278
279			print {$fh} "[global]\nsecret = ", unpack ("H*", $secret), "\n"
280			or die "$file: $!\n";
281			close $fh or die "$file: $!\n";
282
283			$class->new (file => $file)
284			}
285
286	root	1.13	sub _prk_derive_secret($$@) {
287			my ($prk, $length, @info) = @_;
288
289			64 == length $prk
290			or die "derive_secret: key length must be 64 octets\n";
291			$length =~ /\A[0-9]+\z/ && $length <= 255 * 64
292			or die "derive_secret: length must be an integer in 0..16320\n";
293
294	root	1.14	my $info = pack "(N/a)", "anyevent-mcp", @info;
295	root	1.13	my $t = "";
296			my $okm = "";
297			my $i = 0;
298
299			while ($length > length $okm) {
300			$t = Digest::SHA::hmac_sha512 $t . $info . chr ++$i, $prk;
301			$okm .= $t;
302			}
303
304			substr $okm, 0, $length
305			}
306
307			sub derive_secret {
308			my ($self, $length, @info) = @_;
309
310			$self = $self->global unless ref $self;
311
312			my $secret = $self->{section}{global}{secret};
313			$secret =~ /\A[0-9a-fA-F]{128}\z/
314			or die "$self->{file}: missing or invalid secret\n";
315
316			_prk_derive_secret (pack ("H*", $secret), $length, @info)
317			}
318
319	root	1.1	sub credential {
320			my ($self, $purpose, $name, $username) = @_;
321
322			$username = "" unless defined $username;
323
324	root	1.11	$purpose eq "token"
325			or die "Unknown credential purpose '$purpose'\n";
326	root	1.1
327			my $credential = MIME::Base64::encode_base64 (
328	root	1.13	$self->derive_secret (
329	root	1.14	32, $purpose, AnyEvent::MCP::utf8enc (program_name ()),
330	root	1.13	AnyEvent::MCP::utf8enc ($name), AnyEvent::MCP::utf8enc ($username)
331			), ""
332	root	1.1	);
333			$credential =~ y!+/=!-_!d;
334
335			$credential
336			}
337
338	root	1.14	sub program_name {
339			my $name = File::Basename::basename ($0);
340			$name =~ s/\.(?:pl\|perl)\z//;
341			$name eq "-e" ? "perl" : $name
342			}
343
344	root	1.4	sub server_name {
345			my ($name) = @_;
346
347	root	1.14	$name = "default" unless defined $name;
348	root	1.4
349			$name =~ /\A[A-Za-z_][A-Za-z0-9_-]*\z/
350			or die "Invalid MCP server name '$name'\n";
351
352			$name
353			}
354
355			sub http_getopt {
356	root	1.5	my ($name, $bind, $print_url, $tokens) = @_;
357	root	1.4
358	root	1.5	"name=s" => $name, "bind=s" => $bind, "print-url" => $print_url, "token=s@" => $tokens
359	root	1.4	}
360
361	root	1.17	sub auto_rules {
362			my ($self, $name) = @_;
363			my %settings = (
364			%{$self->{section}{"program " . program_name ()} \|\| {}},
365			%{$self->{section}{"instance " . server_name ($name)} \|\| {}},
366			);
367			my @rules;
368
369			for my $key (sort grep /\Aauto-rule\./, keys %settings) {
370			$key =~ /\Aauto-rule\.(.+)\z/
371			or die "Invalid automatic permission rule key '$key'\n";
372			my $value = $settings{$key};
373			next unless length $value;
374			my ($decision, $spec) = $value =~ /\A(allow\|deny)\s+(\S+)\z/
375			or die "Invalid configured automatic permission rule '$key'\n";
376			push @rules, [$decision, $spec];
377			}
378
379			@rules
380			}
381
382	root	1.4	sub server_port {
383			my ($self, $name) = @_;
384
385			$name = server_name $name;
386
387	root	1.14	16384 + ((unpack "n", $self->derive_secret (2, "port", AnyEvent::MCP::utf8enc (program_name ()), AnyEvent::MCP::utf8enc ($name))) & 16383)
388	root	1.4	}
389
390			sub http_settings {
391			my ($self, $name, $bind) = @_;
392
393			$name = server_name $name;
394	root	1.14	my $settings = {
395			%{ $self->{section}{"program " . program_name ()} },
396			%{ $self->{section}{"instance $name"} },
397			};
398	root	1.4	my $port = $self->server_port ($name);
399			my $configured = $settings->{bind} // "127.0.0.1:$port";
400			$configured = "127.0.0.1$configured" if $configured =~ /\A:[0-9]+\z/;
401			my ($configured_host, $configured_port) = AnyEvent::Socket::parse_hostport $configured, $port;
402			defined $configured_host && defined $configured_port
403			&& $configured_port =~ /\A[0-9]+\z/ && $configured_port <= 65535
404			or die "Invalid MCP bind address '$configured'\n";
405
406			$bind = $configured unless defined $bind;
407			$bind = "127.0.0.1$bind" if $bind =~ /\A:[0-9]+\z/;
408
409			my ($host, $service) = AnyEvent::Socket::parse_hostport $bind, $configured_port;
410			defined $host && defined $service && $service =~ /\A[0-9]+\z/ && $service <= 65535
411			or die "Invalid MCP bind address '$bind'\n";
412
413			my %kv = (
414			(map { exists $settings->{$_} ? ($_ => $settings->{$_}) : () }
415	root	1.5	qw(path url_host url_scheme)),
416	root	1.4	name => $name,
417			host => $host,
418			port => $service,
419			);
420
421			unless (AnyEvent::Socket::parse_address $host) {
422			my ($error, @addresses) = Socket::getaddrinfo ($host, undef, { socktype => Socket::SOCK_STREAM () });
423			!$error && @addresses
424			or die "Cannot resolve MCP bind host '$host': $error\n";
425
426	root	1.9	my (undef, $address) = AnyEvent::Socket::unpack_sockaddr $addresses[0]{addr};
427	root	1.4
428			$kv{url_host} //= $host;
429	root	1.9	$kv{host} = AnyEvent::Socket::format_address $address;
430	root	1.4	}
431
432	root	1.11	$kv{tokens} = [exists $settings->{tokens}
433			? split /\s,\s/, $settings->{tokens}, -1
434			: $self->credential ("token", $name)];
435	root	1.4
436			%kv
437			}
438
439			sub http_url {
440			my ($self, $name, $bind, %options) = @_;
441
442	root	1.14	$name = server_name $name;
443
444	root	1.11	# only a derived token depends on the master secret surviving this process.
445	root	1.8	if (($options{auth} \|\| "") ne "none"
446			&& !exists $options{tokens}
447	root	1.14	&& !exists $self->{section}{"instance $name"}{tokens}
448			&& !exists $self->{section}{"program " . program_name ()}{tokens}) {
449	root	1.8	my $stored = ref ($self)->new (file => $self->{file});
450			$stored->{section}{global}{secret} eq $self->{section}{global}{secret}
451			or die "MCP master secret is not persistently stored in $self->{file}\n";
452			}
453	root	1.4
454			require AnyEvent::MCP::Server::HTTP;
455	root	1.8	my %http = $self->http_settings ($name, $bind);
456			delete $http{tokens} if ($options{auth} \|\| "") eq "none";
457	root	1.11
458			AnyEvent::MCP::Server::HTTP->new (%http, %options)->url
459	root	1.4	}
460
461	root	1.1
462			1