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construct/ircd/mods.cc

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C++

// Matrix Construct
//
// Copyright (C) Matrix Construct Developers, Authors & Contributors
// 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
// copyright notice and this permission notice is present in all copies. The
// full license for this software is available in the LICENSE file.
#include <boost/filesystem.hpp>
#include <boost/dll.hpp>
namespace filesystem = boost::filesystem;
namespace load_mode = boost::dll::load_mode;
#include <ircd/asio.h>
#include <ircd/mods/mapi.h> // Module's internal API
#include "mods.h"
ircd::log::log
ircd::mods::log
{
"modules", 'M'
};
const filesystem::path
ircd::mods::suffix
{
boost::dll::shared_library::suffix()
};
///////////////////////////////////////////////////////////////////////////////
//
// mods/mods.h (misc util)
//
std::forward_list<std::string>
ircd::mods::available()
{
using filesystem::path;
using filesystem::directory_iterator;
std::forward_list<std::string> ret;
for(const auto &dir : paths) try
{
for(directory_iterator it(dir); it != directory_iterator(); ++it)
if(is_module(it->path(), std::nothrow))
ret.emplace_front(unpostfixed(relative(it->path(), dir).string()));
}
catch(const filesystem::filesystem_error &e)
{
log::warning
{
log, "Module path [%s]: %s",
dir,
e.what()
};
continue;
}
return ret;
}
filesystem::path
ircd::mods::fullpath(const string_view &name)
{
std::vector<std::string> why;
const filesystem::path path(search(name, why));
if(path.empty())
{
for(const auto &str : why)
log::error
{
log, "candidate for module '%s' failed: %s",
name,
str
};
throw error
{
"No valid module by name `%s'", name
};
}
return path;
}
std::string
ircd::mods::search(const string_view &name)
{
std::vector<std::string> why;
return search(name, why);
}
std::string
ircd::mods::search(const string_view &name,
std::vector<std::string> &why)
{
using filesystem::path;
const path path
{
postfixed(name)
};
if(!path.is_relative())
{
why.resize(why.size() + 1);
return is_module(path, why.back())?
std::string{name}:
std::string{};
}
else for(const auto &dir : paths)
{
why.resize(why.size() + 1);
if(is_module(dir/path, why.back()))
return (dir/path).string();
}
return {};
}
bool
ircd::mods::is_module(const string_view &fullpath)
{
return is_module(filesystem::path(std::string{fullpath}));
}
bool
ircd::mods::is_module(const string_view &fullpath,
std::nothrow_t)
{
return is_module(filesystem::path(std::string{fullpath}), std::nothrow);
}
bool
ircd::mods::is_module(const string_view &fullpath,
std::string &why)
{
return is_module(filesystem::path(std::string{fullpath}), why);
}
bool
ircd::mods::is_module(const filesystem::path &path,
std::nothrow_t)
try
{
return is_module(path);
}
catch(const std::exception &e)
{
return false;
}
bool
ircd::mods::is_module(const filesystem::path &path,
std::string &why)
try
{
return is_module(path);
}
catch(const std::exception &e)
{
why = e.what();
return false;
}
bool
ircd::mods::is_module(const filesystem::path &path)
{
const auto syms(symbols(path));
const auto &header_name(mapi::header_symbol_name);
const auto it(std::find(begin(syms), end(syms), header_name));
if(it == end(syms))
throw error
{
"`%s': has no MAPI header (%s)", path.string(), header_name
};
return true;
}
bool
ircd::mods::available(const string_view &name)
{
using filesystem::path;
std::vector<std::string> why;
return !search(name, why).empty();
}
bool
ircd::mods::loaded(const string_view &name)
{
return mod::loaded.count(name);
}
///////////////////////////////////////////////////////////////////////////////
//
// mods/import.h
//
decltype(ircd::mods::imports)
ircd::mods::imports
{};
///////////////////////////////////////////////////////////////////////////////
//
// mods/sym_ptr.h
//
ircd::mods::sym_ptr::sym_ptr(const string_view &modname,
const string_view &symname)
:sym_ptr
{
module(modname), symname
}
{
}
ircd::mods::sym_ptr::sym_ptr(mod &mod,
const string_view &symname)
:sym_ptr
{
module(shared_from(mod)), symname
}
{
}
ircd::mods::sym_ptr::sym_ptr(module module,
const string_view &symname)
:std::weak_ptr<mod>
{
module
}
,ptr{[this, &module, &symname]
{
if(unlikely(!module.has(symname)))
throw undefined_symbol
{
"Could not find symbol '%s' (%s) in module '%s'",
demangle(symname),
symname,
module.name()
};
return module.ptr(symname);
}()}
{
}
///////////////////////////////////////////////////////////////////////////////
//
// mods/module.h
//
ircd::mods::module::module(const string_view &name)
try
:std::shared_ptr<mod>{[&name]
{
// Search for loaded module and increment the reference counter for this handle if loaded.
auto it(mod::loaded.find(name));
if(it != end(mod::loaded))
{
auto &mod(*it->second);
return shared_from(mod);
}
static const load_mode::type flags
{
load_mode::rtld_local |
load_mode::rtld_now
};
const auto path(fullpath(name));
log::debug
{
log, "Attempting to load '%s' @ `%s'",
name,
path.string()
};
const auto ret
{
std::make_shared<mod>(path, flags)
};
// Call the user-supplied init function well after fully loading and
// construction of the module. This way the init function sees the module
// as loaded and can make shared_ptr references, etc.
if(ret->header->init)
ret->header->init();
log::info
{
log, "Loaded module %s v%u \"%s\"",
ret->name(),
ret->header->version,
!ret->description().empty()?
ret->description():
"<no description>"_sv
};
return ret;
}()}
{
}
catch(const std::exception &e)
{
log::error
{
log, "Failed to load '%s': %s",
name,
e.what()
};
}
ircd::string_view
ircd::mods::module::path()
const
{
const mod &mod(*this);
return mods::path(mod);
}
ircd::string_view
ircd::mods::module::name()
const
{
const mod &mod(*this);
return mods::name(mod);
}
bool
ircd::mods::module::has(const string_view &name)
const
{
const mod &mod(*this);
return mods::has(mod, name);
}
///////////////////////////////////////////////////////////////////////////////
//
// mods/symbols.h
//
std::vector<std::string>
ircd::mods::find_symbol(const string_view &symbol)
{
std::vector<std::string> ret;
const auto av(available());
std::copy_if(begin(av), end(av), std::back_inserter(ret), [&symbol]
(const auto &name)
{
return has_symbol(name, symbol);
});
return ret;
}
bool
ircd::mods::has_symbol(const string_view &name,
const string_view &symbol)
{
const auto path(fullpath(name));
if(path.empty())
return false;
const auto syms(symbols(path));
return std::find(begin(syms), end(syms), symbol) != end(syms);
}
std::unordered_map<std::string, std::string>
ircd::mods::mangles(const string_view &fullpath)
{
return mangles(filesystem::path(std::string{fullpath}));
}
std::unordered_map<std::string, std::string>
ircd::mods::mangles(const string_view &fullpath,
const string_view &section)
{
return mangles(filesystem::path(std::string{fullpath}), section);
}
std::unordered_map<std::string, std::string>
ircd::mods::mangles(const filesystem::path &path)
{
return mangles(mods::symbols(path));
}
std::unordered_map<std::string, std::string>
ircd::mods::mangles(const filesystem::path &path,
const string_view &section)
{
return mangles(mods::symbols(path, section));
}
std::unordered_map<std::string, std::string>
ircd::mods::mangles(const std::vector<std::string> &symbols)
{
std::unordered_map<std::string, std::string> ret;
for(const auto &sym : symbols) try
{
ret.emplace(demangle(sym), sym);
}
catch(const not_mangled &e)
{
ret.emplace(sym, sym);
}
return ret;
}
std::vector<std::string>
ircd::mods::symbols(const string_view &fullpath)
{
return symbols(filesystem::path(std::string{fullpath}));
}
std::vector<std::string>
ircd::mods::symbols(const string_view &fullpath,
const string_view &section)
{
return symbols(filesystem::path(std::string{fullpath}), std::string{section});
}
std::vector<std::string>
ircd::mods::symbols(const filesystem::path &path)
{
return info<std::vector<std::string>>(path, []
(boost::dll::library_info &info)
{
return info.symbols();
});
}
std::vector<std::string>
ircd::mods::symbols(const filesystem::path &path,
const string_view &section)
{
return info<std::vector<std::string>>(path, [&section]
(boost::dll::library_info &info)
{
return info.symbols(std::string{section});
});
}
std::vector<std::string>
ircd::mods::sections(const string_view &fullpath)
{
return sections(filesystem::path(std::string{fullpath}));
}
std::vector<std::string>
ircd::mods::sections(const filesystem::path &path)
{
return info<std::vector<std::string>>(path, []
(boost::dll::library_info &info)
{
return info.sections();
});
}
template<class R,
class F>
R
ircd::mods::info(const filesystem::path &path,
F&& closure)
{
if(!exists(path))
throw filesystem_error
{
"`%s' does not exist", path.string()
};
if(!is_regular_file(path))
throw filesystem_error
{
"`%s' is not a file", path.string()
};
boost::dll::library_info info(path);
return closure(info);
}
///////////////////////////////////////////////////////////////////////////////
//
// mods/paths.h
//
namespace ircd::mods
{
extern const filesystem::path modroot;
}
decltype(ircd::mods::modroot)
ircd::mods::modroot
{
std::string{ircd::fs::get(ircd::fs::MODULES)}
};
decltype(ircd::mods::paths)
ircd::mods::paths
{};
std::string
ircd::mods::unpostfixed(const string_view &name)
{
return unpostfixed(std::string{name});
}
std::string
ircd::mods::unpostfixed(std::string name)
{
return unpostfixed(filesystem::path(std::move(name))).string();
}
std::string
ircd::mods::postfixed(const string_view &name)
{
return postfixed(std::string{name});
}
std::string
ircd::mods::postfixed(std::string name)
{
return postfixed(filesystem::path(std::move(name))).string();
}
filesystem::path
ircd::mods::unpostfixed(const filesystem::path &path)
{
if(extension(path) != suffix)
return path;
return filesystem::path(path).replace_extension();
}
filesystem::path
ircd::mods::postfixed(const filesystem::path &path)
{
if(extension(path) == suffix)
return path;
filesystem::path ret(path);
return ret += suffix;
}
filesystem::path
ircd::mods::prefix_if_relative(const filesystem::path &path)
{
return path.is_relative()? (modroot / path) : path;
}
//
// paths::paths
//
ircd::mods::paths::paths()
:std::vector<std::string>
{{
modroot.string()
}}
{
}
bool
ircd::mods::paths::add(const string_view &dir)
{
using filesystem::path;
const path path
{
prefix_if_relative(std::string{dir})
};
if(!exists(path))
throw filesystem_error
{
"path `%s' (%s) does not exist", dir, path.string()
};
if(!is_directory(path))
throw filesystem_error
{
"path `%s' (%s) is not a directory", dir, path.string()
};
if(added(dir))
return false;
emplace(begin(), dir);
return true;
}
bool
ircd::mods::paths::add(const string_view &dir,
std::nothrow_t)
try
{
return add(dir);
}
catch(const std::exception &e)
{
log::error
{
log, "Failed to add path: %s", e.what()
};
return false;
}
bool
ircd::mods::paths::del(const string_view &dir)
{
std::remove(begin(), end(), prefix_if_relative(std::string{dir}).string());
return true;
}
bool
ircd::mods::paths::added(const string_view &dir)
const
{
return std::find(begin(), end(), dir) != end();
}
///////////////////////////////////////////////////////////////////////////////
//
// mods/mods.h
//
template<> uint8_t *
ircd::mods::ptr<uint8_t>(mod &mod,
const string_view &sym)
{
return &mod.handle.get<uint8_t>(std::string{sym});
}
template<>
const uint8_t *
ircd::mods::ptr<const uint8_t>(const mod &mod,
const string_view &sym)
{
return &mod.handle.get<const uint8_t>(std::string{sym});
}
bool
ircd::mods::has(const mod &mod,
const string_view &name)
{
return mod.handle.has(std::string{name});
}
ircd::string_view
ircd::mods::name(const mod &mod)
{
return mod.name();
}
ircd::string_view
ircd::mods::path(const mod &mod)
{
return mod.location();
}
///////////////////////////////////////////////////////////////////////////////
//
// (internal) mods.h
//
decltype(ircd::mods::mod::loading)
ircd::mods::mod::loading
{};
decltype(ircd::mods::mod::loaded)
ircd::mods::mod::loaded
{};
ircd::mods::mod::mod(const filesystem::path &path,
const load_mode::type &mode)
try
:path{path}
,mode{mode}
//,mangles{mods::mangles(path)}
,handle{[this, &path, &mode]
{
const auto theirs
{
std::get_terminate()
};
const auto ours([]
{
log::critical
{
log, "std::terminate() called during the static construction of a module."
};
if(std::current_exception()) try
{
std::rethrow_exception(std::current_exception());
}
catch(const std::exception &e)
{
log::error
{
log, "%s", e.what()
};
}
});
const unwind reset{[this, &theirs]
{
assert(loading.top() == this);
loading.pop();
std::set_terminate(theirs);
}};
loading.push(this);
std::set_terminate(ours);
return boost::dll::shared_library{path, mode};
}()}
,_name
{
unpostfixed(handle.location().filename().string())
}
,_location
{
handle.location().string()
}
,header
{
&handle.get<mapi::header>(mapi::header_symbol_name)
}
{
log::debug
{
log, "Loaded static segment of '%s' @ `%s' with %zu symbols",
name(),
location(),
mangles.size()
};
if(unlikely(!header))
throw error
{
"Unexpected null header"
};
if(header->magic != mapi::MAGIC)
throw error
{
"Bad magic [%04x] need: [%04x]", header->magic, mapi::MAGIC
};
// Tell the module where to find us.
header->self = this;
// Set some basic metadata
auto &meta(header->meta);
meta["name"] = name();
meta["location"] = location();
if(!loading.empty())
{
const auto &m(mod::loading.top());
m->children.emplace_back(this);
log::debug
{
log, "Module '%s' recursively loaded by '%s'",
name(),
m->path.filename().string()
};
}
// Without init exception, the module is now considered loaded.
assert(!loaded.count(name()));
loaded.emplace(name(), this);
}
catch(const boost::system::system_error &e)
{
switch(e.code().value())
{
case boost::system::errc::bad_file_descriptor:
{
const string_view what(e.what());
const auto pos(what.find("undefined symbol: "));
if(pos == std::string_view::npos)
break;
const string_view msg(what.substr(pos));
const std::string mangled(between(msg, ": ", ")"));
const std::string demangled(demangle(mangled));
throw error
{
"undefined symbol: '%s' (%s)", demangled, mangled
};
}
default:
break;
}
throw error
{
"%s", string(e)
};
}
// Allows module to communicate static destruction is taking place when mapi::header
// destructs. If dlclose() returns without this being set, dlclose() lied about really
// unloading the module. That is considered a "stuck" module.
bool ircd::mapi::static_destruction;
ircd::mods::mod::~mod()
noexcept try
{
log::debug
{
log, "Attempting unload module '%s' @ `%s'",
name(),
location()
};
unload();
const size_t erased(loaded.erase(name()));
assert(erased == 1);
}
catch(const std::exception &e)
{
log::critical
{
log, "Module @%p unload: %s",
(const void *)this,
e.what()
};
if(!ircd::debugmode)
return;
}
bool
ircd::mods::mod::unload()
{
if(!handle.is_loaded())
return false;
if(header->fini)
header->fini();
// Save the children! dlclose() does not like to be called recursively during static
// destruction of a module. The mod ctor recorded all of the modules loaded while this
// module was loading so we can reverse the record and unload them here.
// Note: If the user loaded more modules from inside their module they will have to dtor them
// before 'static destruction' does. They can also do that by adding them to this vector.
std::for_each(rbegin(this->children), rend(this->children), []
(mod *const &ptr)
{
if(shared_from(*ptr).use_count() <= 2)
ptr->unload();
});
log::debug
{
log, "Attempting static unload for '%s' @ `%s'",
name(),
location()
};
mapi::static_destruction = false;
handle.unload();
assert(!handle.is_loaded());
if(!mapi::static_destruction)
{
log.critical("Module \"%s\" is stuck and failing to unload.", name());
log.critical("Module \"%s\" may result in undefined behavior if not fixed.", name());
}
else log::info
{
log, "Unloaded '%s'", name()
};
return true;
}