#
# Copyright (C) 2008-2010 Wayne Meissner
#
# This file is part of ruby-ffi.
#
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
#
# * Redistributions of source code must retain the above copyright notice, this
# list of conditions and the following disclaimer.
# * Redistributions in binary form must reproduce the above copyright notice
# this list of conditions and the following disclaimer in the documentation
# and/or other materials provided with the distribution.
# * Neither the name of the Ruby FFI project nor the names of its contributors
# may be used to endorse or promote products derived from this software
# without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
# DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
# SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
# CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
# OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.#
module FFI
CURRENT_PROCESS = USE_THIS_PROCESS_AS_LIBRARY = Object.new
# @param [#to_s] lib library name
# @return [String] library name formatted for current platform
# Transform a generic library name to a platform library name
# @example
# # Linux
# FFI.map_library_name 'c' # -> "libc.so.6"
# FFI.map_library_name 'jpeg' # -> "libjpeg.so"
# # Windows
# FFI.map_library_name 'c' # -> "msvcrt.dll"
# FFI.map_library_name 'jpeg' # -> "jpeg.dll"
def self.map_library_name(lib)
# Mangle the library name to reflect the native library naming conventions
lib = lib.to_s unless lib.kind_of?(String)
lib = Library::LIBC if lib == 'c'
if lib && File.basename(lib) == lib
lib = Platform::LIBPREFIX + lib unless lib =~ /^#{Platform::LIBPREFIX}/
r = Platform::IS_GNU ? "\\.so($|\\.[1234567890]+)" : "\\.#{Platform::LIBSUFFIX}$"
lib += ".#{Platform::LIBSUFFIX}" unless lib =~ /#{r}/
end
lib
end
# Exception raised when a function is not found in libraries
class NotFoundError < LoadError
def initialize(function, *libraries)
super("Function '#{function}' not found in [#{libraries[0].nil? ? 'current process' : libraries.join(", ")}]")
end
end
# This module is the base to use native functions.
#
# A basic usage may be:
# require 'ffi'
#
# module Hello
# extend FFI::Library
# ffi_lib FFI::Library::LIBC
# attach_function 'puts', [ :string ], :int
# end
#
# Hello.puts("Hello, World")
#
#
module Library
CURRENT_PROCESS = FFI::CURRENT_PROCESS
LIBC = FFI::Platform::LIBC
# @param mod extended object
# @return [nil]
# @raise {RuntimeError} if +mod+ is not a Module
# Test if extended object is a Module. If not, raise RuntimeError.
def self.extended(mod)
raise RuntimeError.new("must only be extended by module") unless mod.kind_of?(Module)
end
# @param [Array] names names of libraries to load
# @return [Array<DynamicLibrary>]
# @raise {LoadError} if a library cannot be opened
# Load native libraries.
def ffi_lib(*names)
raise LoadError.new("library names list must not be empty") if names.empty?
lib_flags = defined?(@ffi_lib_flags) ? @ffi_lib_flags : FFI::DynamicLibrary::RTLD_LAZY | FFI::DynamicLibrary::RTLD_LOCAL
ffi_libs = names.map do |name|
if name == FFI::CURRENT_PROCESS
FFI::DynamicLibrary.open(nil, FFI::DynamicLibrary::RTLD_LAZY | FFI::DynamicLibrary::RTLD_LOCAL)
else
libnames = (name.is_a?(::Array) ? name : [ name ]).map { |n| [ n, FFI.map_library_name(n) ].uniq }.flatten.compact
lib = nil
errors = {}
libnames.each do |libname|
begin
orig = libname
lib = FFI::DynamicLibrary.open(libname, lib_flags)
break if lib
rescue Exception => ex
ldscript = false
if ex.message =~ /(([^ \t()])+\.so([^ \t:()])*):([ \t])*(invalid ELF header|file too short|invalid file format)/
if File.read($1) =~ /(?:GROUP|INPUT) *\( *([^ \)]+)/
libname = $1
ldscript = true
end
end
# TODO better library lookup logic
unless libname.to_s.start_with?("/")
path = ['/usr/lib/','/usr/local/lib/'].find do |pth|
File.exist?(pth + libname)
end
if path
libname = path + libname
retry
end
end
if ldscript
retry
else
libr = (orig == libname ? orig : "#{orig} #{libname}")
errors[libr] = ex
end
end
end
if lib.nil?
raise LoadError.new(errors.values.join(".\n"))
end
# return the found lib
lib
end
end
@ffi_libs = ffi_libs
end
# Set the calling convention for {#attach_function} and {#callback}
#
# @see http://en.wikipedia.org/wiki/Stdcall#stdcall
# @note +:stdcall+ is typically used for attaching Windows API functions
#
# @param [Symbol] convention one of +:default+, +:stdcall+
# @return [Symbol] the new calling convention
def ffi_convention(convention = nil)
@ffi_convention ||= :default
@ffi_convention = convention if convention
@ffi_convention
end
# @see #ffi_lib
# @return [Array<FFI::DynamicLibrary>] array of currently loaded FFI libraries
# @raise [LoadError] if no libraries have been loaded (using {#ffi_lib})
# Get FFI libraries loaded using {#ffi_lib}.
def ffi_libraries
raise LoadError.new("no library specified") if !defined?(@ffi_libs) || @ffi_libs.empty?
@ffi_libs
end
# Flags used in {#ffi_lib}.
#
# This map allows you to supply symbols to {#ffi_lib_flags} instead of
# the actual constants.
FlagsMap = {
:global => DynamicLibrary::RTLD_GLOBAL,
:local => DynamicLibrary::RTLD_LOCAL,
:lazy => DynamicLibrary::RTLD_LAZY,
:now => DynamicLibrary::RTLD_NOW
}
# Sets library flags for {#ffi_lib}.
#
# @example
# ffi_lib_flags(:lazy, :local) # => 5
#
# @param [Symbol, …] flags (see {FlagsMap})
# @return [Fixnum] the new value
def ffi_lib_flags(*flags)
@ffi_lib_flags = flags.inject(0) { |result, f| result | FlagsMap[f] }
end
##
# @overload attach_function(func, args, returns, options = {})
# @example attach function without an explicit name
# module Foo
# extend FFI::Library
# ffi_lib FFI::Library::LIBC
# attach_function :malloc, [:size_t], :pointer
# end
# # now callable via Foo.malloc
# @overload attach_function(name, func, args, returns, options = {})
# @example attach function with an explicit name
# module Bar
# extend FFI::Library
# ffi_lib FFI::Library::LIBC
# attach_function :c_malloc, :malloc, [:size_t], :pointer
# end
# # now callable via Bar.c_malloc
#
# Attach C function +func+ to this module.
#
#
# @param [#to_s] name name of ruby method to attach as
# @param [#to_s] func name of C function to attach
# @param [Array<Symbol>] args an array of types
# @param [Symbol] returns type of return value
# @option options [Boolean] :blocking (@blocking) set to true if the C function is a blocking call
# @option options [Symbol] :convention (:default) calling convention (see {#ffi_convention})
# @option options [FFI::Enums] :enums
# @option options [Hash] :type_map
#
# @return [FFI::VariadicInvoker]
#
# @raise [FFI::NotFoundError] if +func+ cannot be found in the attached libraries (see {#ffi_lib})
def attach_function(name, func, args, returns = nil, options = nil)
mname, a2, a3, a4, a5 = name, func, args, returns, options
cname, arg_types, ret_type, opts = (a4 && (a2.is_a?(String) || a2.is_a?(Symbol))) ? [ a2, a3, a4, a5 ] : [ mname.to_s, a2, a3, a4 ]
# Convert :foo to the native type
arg_types = arg_types.map { |e| find_type(e) }
options = {
:convention => ffi_convention,
:type_map => defined?(@ffi_typedefs) ? @ffi_typedefs : nil,
:blocking => defined?(@blocking) && @blocking,
:enums => defined?(@ffi_enums) ? @ffi_enums : nil,
}
@blocking = false
options.merge!(opts) if opts && opts.is_a?(Hash)
# Try to locate the function in any of the libraries
invokers = []
ffi_libraries.each do |lib|
if invokers.empty?
begin
function = nil
function_names(cname, arg_types).find do |fname|
function = lib.find_function(fname)
end
raise LoadError unless function
invokers << if arg_types.length > 0 && arg_types[arg_types.length - 1] == FFI::NativeType::VARARGS
VariadicInvoker.new(function, arg_types, find_type(ret_type), options)
else
Function.new(find_type(ret_type), arg_types, function, options)
end
rescue LoadError
end
end
end
invoker = invokers.compact.shift
raise FFI::NotFoundError.new(cname.to_s, ffi_libraries.map { |lib| lib.name }) unless invoker
invoker.attach(self, mname.to_s)
invoker
end
# @param [#to_s] name function name
# @param [Array] arg_types function's argument types
# @return [Array<String>]
# This function returns a list of possible names to lookup.
# @note Function names on windows may be decorated if they are using stdcall. See
# * http://en.wikipedia.org/wiki/Name_mangling#C_name_decoration_in_Microsoft_Windows
# * http://msdn.microsoft.com/en-us/library/zxk0tw93%28v=VS.100%29.aspx
# * http://en.wikibooks.org/wiki/X86_Disassembly/Calling_Conventions#STDCALL
# Note that decorated names can be overridden via def files. Also note that the
# windows api, although using, doesn't have decorated names.
def function_names(name, arg_types)
result = [name.to_s]
if ffi_convention == :stdcall
# Get the size of each parameter
size = arg_types.inject(0) do |mem, arg|
size = arg.size
# The size must be a multiple of 4
size += (4 - size) % 4
mem + size
end
result << "_#{name.to_s}@#{size}" # win32
result << "#{name.to_s}@#{size}" # win64
end
result
end
# @overload attach_variable(mname, cname, type)
# @param [#to_s] mname name of ruby method to attach as
# @param [#to_s] cname name of C variable to attach
# @param [DataConverter, Struct, Symbol, Type] type C variable's type
# @example
# module Bar
# extend FFI::Library
# ffi_lib 'my_lib'
# attach_variable :c_myvar, :myvar, :long
# end
# # now callable via Bar.c_myvar
# @overload attach_variable(cname, type)
# @param [#to_s] mname name of ruby method to attach as
# @param [DataConverter, Struct, Symbol, Type] type C variable's type
# @example
# module Bar
# extend FFI::Library
# ffi_lib 'my_lib'
# attach_variable :myvar, :long
# end
# # now callable via Bar.myvar
# @return [DynamicLibrary::Symbol]
# @raise {FFI::NotFoundError} if +cname+ cannot be found in libraries
#
# Attach C variable +cname+ to this module.
def attach_variable(mname, a1, a2 = nil)
cname, type = a2 ? [ a1, a2 ] : [ mname.to_s, a1 ]
address = nil
ffi_libraries.each do |lib|
begin
address = lib.find_variable(cname.to_s)
break unless address.nil?
rescue LoadError
end
end
raise FFI::NotFoundError.new(cname, ffi_libraries) if address.nil? || address.null?
if type.is_a?(Class) && type < FFI::Struct
# If it is a global struct, just attach directly to the pointer
s = type.new(address)
self.module_eval <<-code, __FILE__, __LINE__
@@ffi_gvar_#{mname} = s
def self.#{mname}
@@ffi_gvar_#{mname}
end
code
else
sc = Class.new(FFI::Struct)
sc.layout :gvar, find_type(type)
s = sc.new(address)
#
# Attach to this module as mname/mname=
#
self.module_eval <<-code, __FILE__, __LINE__
@@ffi_gvar_#{mname} = s
def self.#{mname}
@@ffi_gvar_#{mname}[:gvar]
end
def self.#{mname}=(value)
@@ffi_gvar_#{mname}[:gvar] = value
end
code
end
address
end
# @overload callback(name, params, ret)
# @param name callback name to add to type map
# @param [Array] params array of parameters' types
# @param [DataConverter, Struct, Symbol, Type] ret callback return type
# @overload callback(params, ret)
# @param [Array] params array of parameters' types
# @param [DataConverter, Struct, Symbol, Type] ret callback return type
# @return [FFI::CallbackInfo]
def callback(*args)
raise ArgumentError, "wrong number of arguments" if args.length < 2 || args.length > 3
name, params, ret = if args.length == 3
args
else
[ nil, args[0], args[1] ]
end
native_params = params.map { |e| find_type(e) }
raise ArgumentError, "callbacks cannot have variadic parameters" if native_params.include?(FFI::Type::VARARGS)
options = Hash.new
options[:convention] = ffi_convention
options[:enums] = @ffi_enums if defined?(@ffi_enums)
cb = FFI::CallbackInfo.new(find_type(ret), native_params, options)
# Add to the symbol -> type map (unless there was no name)
unless name.nil?
typedef cb, name
end
cb
end
# Register or get an already registered type definition.
#
# To register a new type definition, +old+ should be a {FFI::Type}. +add+
# is in this case the type definition.
#
# If +old+ is a {DataConverter}, a {Type::Mapped} is returned.
#
# If +old+ is +:enum+
# * and +add+ is an +Array+, a call to {#enum} is made with +add+ as single parameter;
# * in others cases, +info+ is used to create a named enum.
#
# If +old+ is a key for type map, #typedef get +old+ type definition.
#
# @param [DataConverter, Symbol, Type] old
# @param [Symbol] add
# @param [Symbol] info
# @return [FFI::Enum, FFI::Type]
def typedef(old, add, info=nil)
@ffi_typedefs = Hash.new unless defined?(@ffi_typedefs)
@ffi_typedefs[add] = if old.kind_of?(FFI::Type)
old
elsif @ffi_typedefs.has_key?(old)
@ffi_typedefs[old]
elsif old.is_a?(DataConverter)
FFI::Type::Mapped.new(old)
elsif old == :enum
if add.kind_of?(Array)
self.enum(add)
else
self.enum(info, add)
end
else
FFI.find_type(old)
end
end
# @overload enum(name, values)
# Create a named enum.
# @example
# enum :foo, [:zero, :one, :two] # named enum
# @param [Symbol] name name for new enum
# @param [Array] values values for enum
# @overload enum(*args)
# Create an unnamed enum.
# @example
# enum :zero, :one, :two # unnamed enum
# @param args values for enum
# @overload enum(values)
# Create an unnamed enum.
# @example
# enum [:zero, :one, :two] # unnamed enum, equivalent to above example
# @param [Array] values values for enum
# @overload enum(native_type, name, values)
# Create a named enum and specify the native type.
# @example
# enum FFI::Type::UINT64, :foo, [:zero, :one, :two] # named enum
# @param [FFI::Type] native_type native type for new enum
# @param [Symbol] name name for new enum
# @param [Array] values values for enum
# @overload enum(native_type, *args)
# Create an unnamed enum and specify the native type.
# @example
# enum FFI::Type::UINT64, :zero, :one, :two # unnamed enum
# @param [FFI::Type] native_type native type for new enum
# @param args values for enum
# @overload enum(native_type, values)
# Create an unnamed enum and specify the native type.
# @example
# enum Type::UINT64, [:zero, :one, :two] # unnamed enum, equivalent to above example
# @param [FFI::Type] native_type native type for new enum
# @param [Array] values values for enum
# @return [FFI::Enum]
# Create a new {FFI::Enum}.
def enum(*args)
native_type = args.first.kind_of?(FFI::Type) ? args.shift : nil
name, values = if args[0].kind_of?(Symbol) && args[1].kind_of?(Array)
[ args[0], args[1] ]
elsif args[0].kind_of?(Array)
[ nil, args[0] ]
else
[ nil, args ]
end
@ffi_enums = FFI::Enums.new unless defined?(@ffi_enums)
@ffi_enums << (e = native_type ? FFI::Enum.new(native_type, values, name) : FFI::Enum.new(values, name))
# If called as enum :foo, [ :zero, :one, :two ], add a typedef alias
typedef(e, name) if name
e
end
# @param name
# @return [FFI::Enum]
# Find an enum by name.
def enum_type(name)
@ffi_enums.find(name) if defined?(@ffi_enums)
end
# @param symbol
# @return [FFI::Enum]
# Find an enum by a symbol it contains.
def enum_value(symbol)
@ffi_enums.__map_symbol(symbol)
end
# @param [DataConverter, Type, Struct, Symbol] t type to find
# @return [Type]
# Find a type definition.
def find_type(t)
if t.kind_of?(Type)
t
elsif defined?(@ffi_typedefs) && @ffi_typedefs.has_key?(t)
@ffi_typedefs[t]
elsif t.is_a?(Class) && t < Struct
Type::POINTER
elsif t.is_a?(DataConverter)
# Add a typedef so next time the converter is used, it hits the cache
typedef Type::Mapped.new(t), t
end || FFI.find_type(t)
end
end
end