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Code Issues Releases Wiki Activity

ircd::mods: Improve MAPI header layout; various cleanup.

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This commit is contained in:
Jason Volk 2018-10-25 13:03:07 -07:00
parent 30d938530a
commit d19edbda98
3 changed files with 131 additions and 73 deletions
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128
include/ircd/mods/mapi.h
View file

@ -15,66 +15,85 @@
namespace ircd::mapi
{
struct header;
struct metablock;
using magic_t = uint16_t;
using version_t = uint16_t;
using metadata = std::map<string_view, string_view, std::less<>>;
using init_function = std::function<void ()>;
using fini_function = std::function<void ()>;
using meta_data = std::map<string_view, string_view, std::less<>>;
using init_func = std::function<void ()>;
using fini_func = std::function<void ()>;
/// Used to communicate whether a module unload actually took place. dlclose() is allowed to return
/// success but the actual static destruction of the module's contents doesn't lie. (mods.cc)
extern bool static_destruction;
/// The name of the header variable in the module must match this string
const char *const header_symbol_name
{
"IRCD_MODULE"
};
constexpr const magic_t MAGIC
{
0x4D41
};
// Used to communicate whether a module unload actually took place. dlclose() is allowed to return
// success but the actual static destruction of the module's contents doesn't lie. (mods.cc)
extern bool static_destruction;
}
/// The magic number at the front of the header
constexpr const ircd::mapi::magic_t
IRCD_MAPI_MAGIC
{
0x4D41
};
/// The version number of this module's header.
constexpr const ircd::mapi::version_t
IRCD_MAPI_VERSION
{
4
};
struct ircd::mapi::header
{
magic_t magic; // The magic must match MAGIC
version_t version; // Version indicator
int64_t timestamp; // Module's compile epoch
init_function init; // Executed after dlopen()
fini_function fini; // Executed before dlclose()
metadata meta; // Various key-value metadata
mods::mod *self; // Module instance once loaded
const magic_t magic {IRCD_MAPI_MAGIC}; // The magic must match
const version_t version {IRCD_MAPI_VERSION}; // Version indicator
const int32_t _reserved_ {0}; // MBZ
const int64_t timestamp {RB_DATECODE}; // Module's compile epoch
std::unique_ptr<metablock> meta; // Non-standard-layout header data
mods::mod *self {nullptr}; // Point to mod instance once loaded
// get and set metadata
auto &operator[](const string_view &s) const;
auto &operator[](const string_view &s);
const string_view &operator[](const string_view &s) const;
string_view &operator[](const string_view &s);
// become self
operator const mods::mod &() const;
operator mods::mod &();
header(const string_view &desc = "<no description>",
init_function = {},
fini_function = {});
header(const string_view & = "<no description>",
init_func = {},
fini_func = {});
header(header &&) = delete;
header(const header &) = delete;
~header() noexcept;
};
inline
ircd::mapi::header::header(const string_view &desc,
init_function init,
fini_function fini)
:magic(MAGIC)
,version(4)
,timestamp(RB_DATECODE)
,init{std::move(init)}
,fini{std::move(fini)}
,meta
struct ircd::mapi::metablock
{
{ "description", desc }
init_func init; // Executed after dlopen()
fini_func fini; // Executed before dlclose()
meta_data meta; // Various key-value metadata
};
inline
ircd::mapi::header::header(const string_view &description,
init_func init,
fini_func fini)
:meta
{
new metablock
{
std::move(init), std::move(fini), meta_data
{
{ "description", description }
}
}
}
,self{nullptr}
{
}
@ -85,30 +104,15 @@ noexcept
static_destruction = true;
}
inline ircd::mapi::header::operator
mods::mod &()
{
assert(self);
return *self;
}
static_assert
(
std::is_standard_layout<ircd::mapi::header>(),
"The MAPI header must be standard layout so the magic and version numbers"
" can be parsed from the shared object file by external applications."
);
inline ircd::mapi::header::operator
const mods::mod &()
const
{
assert(self);
return *self;
}
inline auto &
ircd::mapi::header::operator[](const string_view &key)
{
return meta[key];
}
inline auto &
ircd::mapi::header::operator[](const string_view &key)
const
{
return meta.at(key);
}
static_assert
(
sizeof(ircd::mapi::header) == 2 + 2 + 4 + 8 + 8 + 8,
"The MAPI header size has changed on this platform."
);

71
ircd/mods.cc
View file

@ -116,19 +116,18 @@ try
"Unexpected null header"
};
if(header->magic != mapi::MAGIC)
if(header->magic != IRCD_MAPI_MAGIC)
throw error
{
"Bad magic [%04x] need: [%04x]", header->magic, mapi::MAGIC
"Bad magic [%04x] need: [%04x]", header->magic, IRCD_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();
(*this)["name"] = name();
(*this)["location"] = location();
if(!loading.empty())
{
@ -214,8 +213,10 @@ ircd::mods::mod::unload()
};
// Call the user's unloading function here.
if(header->fini)
header->fini();
assert(header);
assert(header->meta);
if(header->meta->fini)
header->meta->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
@ -256,6 +257,56 @@ ircd::mods::mod::unload()
return true;
}
ircd::string_view &
ircd::mods::mod::operator[](const string_view &key)
{
assert(header);
return header->operator[](key);
}
const ircd::string_view &
ircd::mods::mod::operator[](const string_view &key)
const
{
assert(header);
return header->operator[](key);
}
///////////////////////////////////////////////////////////////////////////////
//
// mods/mapi.h
//
ircd::mapi::header::operator
mods::mod &()
{
assert(self);
return *self;
}
ircd::mapi::header::operator
const mods::mod &()
const
{
assert(self);
return *self;
}
ircd::string_view &
ircd::mapi::header::operator[](const string_view &key)
{
assert(meta);
return meta->meta[key];
}
const ircd::string_view &
ircd::mapi::header::operator[](const string_view &key)
const
{
assert(meta);
return meta->meta.at(key);
}
///////////////////////////////////////////////////////////////////////////////
//
// mods/mods.h (misc util)
@ -594,8 +645,10 @@ try
// 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();
assert(ret->header);
assert(ret->header->meta);
if(ret->header->meta->init)
ret->header->meta->init();
log::info
{

5
ircd/mods.h
View file

@ -54,9 +54,10 @@ struct ircd::mods::mod
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); }
const string_view &operator[](const string_view &s) const;
string_view &operator[](const string_view &s);
// Convenience accessors
auto &name() const { return _name; }
auto &location() const { return _location; }
auto &version() const { return header->version; }