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construct/ircd/mods.cc
2017-03-17 17:46:20 -07:00

701 lines
15 KiB
C++

/*
* ircd-ratbox: A slightly useful ircd.
* modules.c: A module loader.
*
* Copyright (C) 1990 Jarkko Oikarinen and University of Oulu, Co Center
* Copyright (C) 1996-2002 Hybrid Development Team
* Copyright (C) 2002-2005 ircd-ratbox development team
* Copyright (C) 2016 Charybdis Development Team
* Copyright (C) 2016 Jason Volk <jason@zemos.net>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
* USA
*/
#include <boost/filesystem.hpp>
#include <boost/dll.hpp>
namespace filesystem = boost::filesystem;
namespace load_mode = boost::dll::load_mode;
#include <ircd/mapi.h> // Module's internal API
namespace ircd {
namespace mods {
struct mod
:std::enable_shared_from_this<mod>
{
static std::map<std::string, mod *> loaded;
boost::dll::shared_library handle;
mapi::header *header;
// Metadata
auto &operator[](const std::string &s) const { return header->meta.operator[](s); }
auto &operator[](const std::string &s) { return header->meta.operator[](s); }
auto name() const { return handle.location().filename().string(); }
auto location() const { return handle.location().string(); }
auto &version() const { return header->version; }
auto &description() const { return (*this)["description"]; }
bool has(const std::string &name) const;
template<class T> const T &get(const std::string &name) const;
template<class T> T &get(const std::string &name);
template<class T = uint8_t> const T *ptr(const std::string &name) const;
template<class T = uint8_t> T *ptr(const std::string &name);
mod(const filesystem::path &,
const load_mode::type & = load_mode::rtld_local | load_mode::rtld_now);
~mod() noexcept;
};
filesystem::path prefix_if_relative(const filesystem::path &path);
filesystem::path postfixed(const filesystem::path &path);
std::string postfixed(const std::string &name);
template<class R, class F> R info(const filesystem::path &, F&& closure);
std::vector<std::string> sections(const filesystem::path &path);
std::vector<std::string> symbols(const filesystem::path &path);
std::vector<std::string> symbols(const filesystem::path &path, const std::string &section);
// Get the full path of a [valid] available module by name
filesystem::path fullpath(const std::string &name);
// Checks if loadable module containing a mapi header (does not verify the magic)
bool is_module(const filesystem::path &);
bool is_module(const filesystem::path &, std::string &why);
bool is_module(const filesystem::path &, std::nothrow_t);
bool is_module(const std::string &fullpath, std::string &why);
bool is_module(const std::string &fullpath, std::nothrow_t);
bool is_module(const std::string &fullpath);
struct log::log log
{
"modules", 'M'
};
} // namespace mods
} // namespace ircd
ircd::mods::init::init()
{
}
ircd::mods::init::~init()
noexcept
{
}
///////////////////////////////////////////////////////////////////////////////
//
// module
//
namespace ircd {
namespace mods {
} // namespace mods
} // namespace ircd
ircd::mods::module::module(const std::string &name)
try
:std::shared_ptr<mod>{[&name]
{
const auto path(fullpath(name));
const auto filename(postfixed(name));
// Search for loaded module and increment the reference counter for this handle if loaded.
auto it(mod::loaded.find(filename));
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
};
log.debug("Attempting to load '%s' @ `%s'",
filename.c_str(),
path.string().c_str());
return std::make_shared<mod>(path, flags);
}()}
{
}
catch(const std::exception &e)
{
log.error("Failed to load '%s': %s",
name.c_str(),
e.what());
throw;
}
ircd::mods::module::~module()
noexcept
{
}
std::string
ircd::mods::module::path()
const
{
if(unlikely(!*this))
return std::string{};
auto &mod(**this);
return mod.location();
}
std::string
ircd::mods::module::name()
const
{
if(unlikely(!*this))
return std::string{};
auto &mod(**this);
return mod.name();
}
template<> uint8_t *
ircd::mods::module::ptr<uint8_t>(const std::string &name)
{
const auto &mod(**this);
return &mod.handle.get<uint8_t>(name);
}
template<>
const uint8_t *
ircd::mods::module::ptr<const uint8_t>(const std::string &name)
const
{
const auto &mod(**this);
return &mod.handle.get<const uint8_t>(name);
}
bool
ircd::mods::module::has(const std::string &name)
const
{
if(unlikely(!*this))
return false;
const auto &mod(**this);
return mod.handle.has(name);
}
///////////////////////////////////////////////////////////////////////////////
//
// misc
//
namespace ircd {
namespace mods {
} // namespace mods
} // namespace ircd
bool
ircd::mods::loaded(const std::string &name)
{
return mod::loaded.count(postfixed(name));
}
bool
ircd::mods::available(const std::string &name)
{
using filesystem::path;
std::vector<std::string> why;
return !search(name, why).empty();
}
std::string
ircd::mods::search(const std::string &name)
{
std::vector<std::string> why;
return search(name, why);
}
std::vector<std::string>
ircd::mods::find_symbol(const std::string &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 std::string &name,
const std::string &symbol)
{
const auto fullpath(search(name));
if(fullpath.empty())
return false;
const auto syms(symbols(fullpath));
return std::find(begin(syms), end(syms), symbol) != end(syms);
}
filesystem::path
ircd::mods::fullpath(const std::string &name)
{
std::vector<std::string> why;
const filesystem::path path(search(name, why));
if(path.empty())
{
for(const auto &str : why)
log.error("candidate for module '%s' failed: %s",
name.c_str(),
str.c_str());
throw error("No valid module by name `%s'", name.c_str());
}
return path;
}
std::string
ircd::mods::search(const std::string &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())? 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 {};
}
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(relative(it->path(), dir).string());
}
catch(const filesystem::filesystem_error &e)
{
log.warning("Module path [%s]: %s",
dir.c_str(),
e.what());
continue;
}
return ret;
}
bool
ircd::mods::is_module(const std::string &fullpath)
{
return is_module(filesystem::path(fullpath));
}
bool
ircd::mods::is_module(const std::string &fullpath,
std::nothrow_t)
{
return is_module(filesystem::path(fullpath), std::nothrow);
}
bool
ircd::mods::is_module(const std::string &fullpath,
std::string &why)
{
return is_module(filesystem::path(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)
{
if(!exists(path))
throw filesystem_error("`%s' does not exist",
path.string().c_str());
if(!is_regular_file(path))
throw filesystem_error("`%s' is not a file",
path.string().c_str());
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().c_str(),
header_name);
return true;
}
std::vector<std::string>
ircd::mods::sections(const std::string &fullpath)
{
return sections(filesystem::path(fullpath));
}
std::vector<std::string>
ircd::mods::symbols(const std::string &fullpath)
{
return symbols(filesystem::path(fullpath));
}
std::vector<std::string>
ircd::mods::symbols(const std::string &fullpath,
const std::string &section)
{
return symbols(filesystem::path(fullpath), section);
}
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();
});
}
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 std::string &section)
{
return info<std::vector<std::string>>(path, [&section]
(boost::dll::library_info &info)
{
return info.symbols(section);
});
}
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().c_str());
if(!is_regular_file(path))
throw filesystem_error("`%s' is not a file",
path.string().c_str());
boost::dll::library_info info(path);
return closure(info);
}
///////////////////////////////////////////////////////////////////////////////
//
// paths
//
namespace ircd {
namespace mods {
const filesystem::path modroot
{
ircd::path::get(ircd::path::MODULES)
};
struct paths paths;
} // namespace mods
} // namespace ircd
ircd::mods::paths::paths()
:std::vector<std::string>
{{
modroot.string()
}}
{
}
bool
ircd::mods::paths::add(const std::string &dir)
{
using filesystem::path;
const path path(prefix_if_relative(dir));
if(!exists(path))
throw filesystem_error("path `%s' (%s) does not exist",
dir.c_str(),
path.string().c_str());
if(!is_directory(path))
throw filesystem_error("path `%s' (%s) is not a directory",
dir.c_str(),
path.string().c_str());
if(added(dir))
return false;
emplace(begin(), dir);
return true;
}
bool
ircd::mods::paths::add(const std::string &dir,
std::nothrow_t)
try
{
return add(dir);
}
catch(const std::exception &e)
{
log.error("Failed to add path: %s", e.what());
return false;
}
bool
ircd::mods::paths::del(const std::string &dir)
{
std::remove(begin(), end(), prefix_if_relative(dir).string());
return true;
}
bool
ircd::mods::paths::added(const std::string &dir)
const
{
return std::find(begin(), end(), dir) != end();
}
std::string
ircd::mods::postfixed(const std::string &name)
{
return postfixed(filesystem::path(name)).string();
}
filesystem::path
ircd::mods::postfixed(const filesystem::path &path)
{
static const auto suffix(boost::dll::shared_library::suffix());
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;
}
///////////////////////////////////////////////////////////////////////////////
//
// mod (internal)
//
namespace ircd {
namespace mods {
std::map<std::string, mod *> mod::loaded;
} // namespace mods
} // namespace ircd
ircd::mods::mod::mod(const filesystem::path &path,
const load_mode::type &type)
try
:handle
{
path, type
}
,header
{
&handle.get<mapi::header>(mapi::header_symbol_name)
}
{
log.debug("Loaded static segment of '%s' @ `%s'",
name().c_str(),
path.string().c_str());
if(unlikely(!header))
throw error("Unexpected null header");
if(header->magic != mapi::MAGIC)
throw error("Bad magic [%04x] need: [%04x]",
header->magic,
mapi::MAGIC);
// Set some basic metadata
auto &meta(header->meta);
meta["name"] = name();
meta["location"] = location();
// If init throws an exception from here the loading process will back out.
if(header->init)
header->init();
// Without init exception, the module is now considered loaded.
loaded.emplace(name(), this);
log.info("Loaded module %s v%u \"%s\"",
name().c_str(),
header->version,
description().size()? description().c_str() : "<no description>");
}
catch(const boost::system::system_error &e)
{
throw error("%s", e.what());
}
// 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
{
const auto name(this->name());
log.debug("Attempting unload module '%s' @ `%s'",
name.c_str(),
location().c_str());
const size_t erased(loaded.erase(name));
assert(erased == 1);
if(header->fini)
header->fini();
log.debug("Attempting static unload for '%s' @ `%s'",
name.c_str(),
location().c_str());
mapi::static_destruction = false;
handle.unload();
assert(!handle.is_loaded());
if(!mapi::static_destruction)
{
log.error("Module \"%s\" is stuck and failing to unload.", name.c_str());
log.warning("Module \"%s\" may result in undefined behavior if not fixed.", name.c_str());
} else {
log.info("Unloaded '%s'", name.c_str());
}
}
catch(const std::exception &e)
{
log::critical("Module @%p unload: %s",
(const void *)this,
e.what());
if(!ircd::debugmode)
return;
}
template<class T>
T *
ircd::mods::mod::ptr(const std::string &name)
{
return &handle.get<T>(name);
}
template<class T>
const T *
ircd::mods::mod::ptr(const std::string &name)
const
{
return &handle.get<T>(name);
}
template<class T>
T &
ircd::mods::mod::get(const std::string &name)
{
handle.get<T>(name);
}
template<class T>
const T &
ircd::mods::mod::get(const std::string &name)
const
{
handle.get<T>(name);
}
bool
ircd::mods::mod::has(const std::string &name)
const
{
return handle.has(name);
}