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construct/ircd/ircd.cc

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// Matrix Construct
//
// Copyright (C) Matrix Construct Developers, Authors & Contributors
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// Copyright (C) 2016-2018 Jason Volk <jason@zemos.net>
//
// Permission to use, copy, modify, and/or distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
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// copyright notice and this permission notice is present in all copies. The
// full license for this software is available in the LICENSE file.
namespace ircd
{
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// Fundamental context #1; all subsystems live as objects on this stack.
// This is created by ircd::init(), and it executes ircd::main(), it then
// deletes itself and nulls this pointer when finished.
extern ctx::ctx *main_context;
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// Main function. This frame anchors the initialization and destruction of
// all non-static assets provided by the library.
static void main(user_main) noexcept;
}
// internal interface to ircd::run (see ircd/run.h, ircd/run.cc)
namespace ircd::run
{
// change the current runlevel
bool set(const enum level &);
}
/// Records compile-time header version information.
decltype(ircd::version_api)
ircd::version_api
{
"IRCd", info::versions::API, 0, {0, 0, 0}, RB_VERSION
};
/// Records runtime linked library (this library) version information.
decltype(ircd::version_abi)
ircd::version_abi
{
"IRCd", info::versions::ABI, 0, {0, 0, 0}, ircd::info::version
};
/// This item allows the library to indicate to the embedder that they should
/// restart their application (or reload this library if available). The
/// use-case here is for features like the `restart` command in the console
/// module. Such a command triggers a normal quit and the application may exit
/// normally; therefor the embedder should check this item to perform a restart
/// rather than exiting.
///
/// This item is a string to allow for different program options at restart.
/// For now this is limited to space-separated arguments without respect for
/// quoting (for now), so no arguments can have spaces.
///
/// Empty string disables restart. The name of the executable should not be
/// prefixed to the string.
decltype(ircd::restart)
ircd::restart
{
{ "name", "ircd.restart" },
{ "default", std::string{} },
{ "persist", false },
};
/// Coarse mode indicator for debug/developer behavior when and if possible.
/// For example: additional log messages may be enabled by this mode. This
/// option is technically effective in both release builds and debug builds
/// but it controls far less in non-debug builds. This item may be toggled
/// at any time. It doesn't change operational functionality.
decltype(ircd::debugmode)
ircd::debugmode
{
{ "name", "ircd.debugmode" },
{ "default", false },
{ "persist", false },
};
/// When assertions are enabled this further softens runtime behavior to be
/// non-disruptive/non-terminating for diagnostic purposes. Debugging/developer
/// use only. This item may be toggled at any time.
decltype(ircd::soft_assert)
ircd::soft_assert
{
{ "name", "ircd.soft_assert" },
{ "default", false },
{ "persist", false },
};
/// Coarse mode declaration for "maintenance mode" a.k.a. "single user mode"
/// which is intended to be similar to normal operating mode but without
/// services to clients or some background tasks. It is implied and set when
/// write_avoid=true which is itself implied and set by read_only.
decltype(ircd::maintenance)
ircd::maintenance
{
{
{ "name", "ircd.maintenance" },
{ "default", false },
{ "persist", false },
}, []
{
if(!maintenance)
return;
net::listen.set("false");
}
};
/// Coarse mode indicator for degraded operation known as "write-avoid" which
/// is similar to read_only but not hard-enforced. Writes may still occur,
/// such as those manually triggered by an admin. All subsystems and background
/// tasks otherwise depart from normal operation to avoid writes.
decltype(ircd::write_avoid)
ircd::write_avoid
{
{
{ "name", "ircd.write_avoid" },
{ "default", false },
{ "persist", false },
}, []
{
if(!write_avoid)
return;
maintenance.set("true");
}
};
/// Coarse mode declaration for read-only behavior. All subsystems and feature
/// modules respect this indicator by preventing any writes and persistence
/// during execution. This item should be set before ircd::init() to be most
/// effective.
decltype(ircd::read_only)
ircd::read_only
{
{
{ "name", "ircd.read_only" },
{ "default", false },
{ "persist", false },
}, []
{
if(!read_only)
return;
write_avoid.set("true");
}
};
/// Diagnostic options selection. This indicates whether any tests or special
/// behavior should occur rather than normal operation; also allowing for
/// fine-grained options to be conveyed to such tests/diagnostics. While this
/// appears here as coarse library-wide option it does not on its own affect
/// normal server operations just by being set. It affect things only if
/// specific functionality checks and alters its behavior based on the value
/// of this string contextually.
decltype(ircd::diagnostic)
ircd::diagnostic
{
{ "name", "ircd.diagnostic" },
{ "default", string_view{} },
{ "persist", false },
};
/// Main context pointer placement.
decltype(ircd::main_context)
ircd::main_context;
/// Sets up the IRCd and its main context, then returns without blocking.
///
/// Pass the executor obtained from your io_context instance.
///
/// This function will setup the main program loop of libircd. The execution will
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/// occur when your io_context.run() or poll() is further invoked.
///
/// init() can only be called from a run::level::HALT state
void
ircd::init(boost::asio::executor &&executor,
user_main user)
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try
{
// This function must only be called from a HALT state.
if(run::level != run::level::HALT)
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throw error
{
"Cannot init() IRCd from runlevel %s", reflect(run::level)
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};
// Setup the core event loop system starting with the user's supplied ios.
ios::init(std::move(executor));
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// The log is available. but it is console-only until conf opens files.
log::init();
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log::mark("DEADSTART"); // 6600
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// This starts off the log with library information.
info::dump();
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// Setup the main context, which is a new stack executing the function
// ircd::main(). The main_context is the first ircd::ctx to be spawned
// and will be the last to finish.
//
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// The context::POST will delay this spawn until the next io_context
// event slice, so no context switch will occur here. Note that POST has
// to be used here because: A. This init() function is executing on the
// main stack, and context switches can only occur between context stacks,
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// not between contexts and the main stack. B. The user's io_context may or
// may not even be running yet anyway.
//
// (debug compilation) The context::SLICE_EXEMPT flag exempts the context
// from assertions that it's not blocking the process with excessive CPU
// usage or long syscall. Main context can't meet this requirement.
//
context main_context
{
"main",
512_KiB,
std::bind(&ircd::main, std::move(user)),
context::POST | context::SLICE_EXEMPT
};
// The default behavior for ircd::context is to join the ctx on dtor. We
// can't have that here because this is strictly an asynchronous function
// on the main stack. Under normal circumstances, the mc will be entered
// and be able to delete this pointer itself when it finishes. Otherwise
// this must be manually deleted with assurance that mc will never enter.
ircd::main_context = main_context.detach();
// Finally, without prior exception, the commitment to run::level::READY
// is made here. The user can now invoke their ios.run(), or, if they
// have already, IRCd will begin main execution shortly...
run::set(run::level::READY);
}
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catch(const std::exception &e)
{
throw;
}
/// Notifies IRCd to shutdown. A shutdown will occur asynchronously and this
/// function will return immediately. A runlevel change to HALT will be
/// indicated when IRCd has no more work for the ios. When the HALT state
/// is observed the user is free to destruct all resources related to libircd.
///
/// This function is the proper way to shutdown libircd after an init(), and while
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/// your io_context.run() is invoked without stopping your io_context shared by
/// other activities unrelated to libircd. If your io_context has no other activities
/// the run() will then return immediately after IRCd posts its transition to
/// the HALT state.
///
[[gnu::cold]]
bool
ircd::quit()
noexcept
{
log::logf
{
log::star, log::level::DEBUG,
"IRCd quit requested from runlevel:%s ctx:%p main_context:%p",
reflect(run::level),
(const void *)ctx::current,
(const void *)main_context
};
if(main_context) switch(run::level)
{
case run::level::READY:
{
ctx::terminate(*main_context);
main_context = nullptr;
ircd::run::set(run::level::HALT);
return true;
}
case run::level::START:
{
ctx::terminate(*main_context);
main_context = nullptr;
return true;
}
case run::level::RUN:
{
ctx::notify(*main_context);
main_context = nullptr;
return true;
}
case run::level::QUIT:
case run::level::HALT:
case run::level::FAULT:
return false;
}
return false;
}
/// Main context; Main program. Do not call this function directly.
///
/// This function manages the lifetime for all resources and subsystems
/// that don't/can't have their own static initialization. When this
/// function is entered, subsystem init objects are constructed on the
/// frame. The lifetime of those objects is the handle to the lifetime
/// of the subsystem, so destruction will shut down that subsystem.
///
/// The status of this function and IRCd overall can be observed through
/// the ircd::runlevel. The ircd::run::changed callback can be set
/// to be notified on a runlevel change. The user should wait for a runlevel
/// of HALT before destroying IRCd related resources and stopping their
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/// io_context from running more jobs.
///
void
ircd::main(user_main user)
noexcept try
{
// When this function completes without exception, subsystems are done
// shutting down and IRCd transitions to HALT.
const unwind_defer halted{[]
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{
run::set(run::level::HALT);
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}};
// We block interruption/termination of the main context by default;
// this covers most of the functionality performed by this function and
// its callees. This provides consistent and complete runlevel transitions.
const ctx::uninterruptible::nothrow disable_interruption {true};
// When this function is entered IRCd will transition to START indicating
// that subsystems are initializing.
run::set(run::level::START);
// These objects are the init()'s and fini()'s for each subsystem.
// Appearing here ties their life to the main context. Initialization can
// also occur in ircd::init() or static initialization itself if either are
// more appropriate.
ctx::ole::init _ole_; // Thread OffLoad Engine
fs::init _fs_; // Local filesystem
cl::init _cl_; // OpenCL
magic::init _magic_; // libmagic
magick::init _magick_; // ImageMagick
openssl::init _ossl_; // openssl crypto
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net::init _net_; // Networking
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db::init _db_; // RocksDB
client::init _client_; // Client related
server::init _server_; // Server related
js::init _js_; // SpiderMonkey
// Continuation passed to the user's main function.
const auto continuation{[]
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{
// Transition to the QUIT state on unwind.
const unwind quit{[]
{
const ctx::uninterruptible::nothrow disable_interruption {true};
ircd::run::set(run::level::QUIT);
}};
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// Block interruptions again for runlevel transitions.
const ctx::uninterruptible disable_interruption {true};
// IRCd will now transition to the RUN state indicating full functionality.
run::set(run::level::RUN);
// Allow interrupts while running so we can be notified to quit.
const ctx::uninterruptible reenable_interruption {false};
// wait() blocks until the main context is notified or interrupted etc.
// Waiting here will hold open this stack with all of the above objects
// living on it.
ctx::wait();
}};
if(!user)
return continuation();
// Allow interrupts again by default for the duration of the user.
const ctx::uninterruptible reenable_interruption {false};
// Call user.
user(continuation);
}
catch(const std::exception &e)
{
log::critical
{
"IRCd main :%s", e.what()
};
}
catch(const ctx::terminated &)
{
return;
}
catch(...)
{
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log::critical
{
"IRCd main error."
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};
}
/// IRCd uptime in seconds
ircd::seconds
ircd::uptime()
{
return seconds(ircd::time() - info::startup_time);
}