Unhadled C++ exceptions cause abort

The following example demonstrates this

$ ruby -reventmachine -e 'at_exit { puts "bye" }; EventMachine.setuid_string "unknown"'
terminate called after throwing an instance of 'std::runtime_error'
  what():  setuid_string failed: No such file or directory
Aborted (core dumped)
$ echo $?
134

I understand that immediate abort is intended, but I believe rb_fatal should be used to wrap all unhandled C++ exceptions, as letting them pass across library boundaries is not considered a good practice.

Here are some examples:

vladimir@np940x5n:~$ irb
3.0.2 :001 > require 'ffi'
 => true 
3.0.2 :002 > module RbFFI
3.0.2 :003 >   extend FFI::Library
3.0.2 :004 >   ffi_lib FFI::CURRENT_PROCESS
3.0.2 :005 > end
 => [#<FFI::DynamicLibrary:0x000058dfabc49850 @name="[current process]">] 
3.0.2 :006 > require 'fiddle'
 => false 
3.0.2 :007 > rb_eException = Fiddle.dlwrap Exception # Just a hacky way to convert get VALUE representation of Ruby object 
 => 97717656452720 
3.0.2 :008 > RbFFI.attach_function :rb_define_class, [:string, :ulong], :ulong
 => #<FFI::Function address=0x00007bd66cc67d10> 
3.0.2 :009 > rb_eFatal = RbFFI.rb_define_class("fatal", rb_eException)
 => 97717656451440 
3.0.2 :010 > rb_eFatal = RbFFI.rb_define_class("fatal", rb_eException)
 => 97717656451440 
3.0.2 :011 > RbFFI.attach_function :rb_raise, [:ulong, :string, :varargs], :void
 => 
#<FFI::VariadicInvoker:0x000058dfacb21bc0
 @fixed=[#<FFI::Type::Builtin::ULONG size=8 alignment=8>, #<FFI::Type::Builtin::STRING size=8 alignment=8>],
 @type_map=nil> 
3.0.2 :012 > RbFFI.rb_raise rb_eFatal, "fatal"
/home/vladimir/.local/share/rtx/installs/ruby/3.0.2/lib/ruby/gems/3.0.0/gems/ffi-1.16.3/lib/ffi/variadic.rb:47:in `invoke': fatal (fatal)
	from /home/vladimir/.local/share/rtx/installs/ruby/3.0.2/lib/ruby/gems/3.0.0/gems/ffi-1.16.3/lib/ffi/variadic.rb:47:in `call'
	from /home/vladimir/.local/share/rtx/installs/ruby/3.0.2/lib/ruby/gems/3.0.0/gems/ffi-1.16.3/lib/ffi/variadic.rb:62:in `rb_raise'
	from (irb):12:in `<main>'
	from /home/vladimir/.local/share/rtx/installs/ruby/3.0.2/lib/ruby/gems/3.0.0/gems/irb-1.14.0/exe/irb:9:in `<top (required)>'
	from /home/vladimir/.local/share/mise/installs/ruby/3.0.2/bin/irb:25:in `load'
	from /home/vladimir/.local/share/mise/installs/ruby/3.0.2/bin/irb:25:in `<main>'
	from /home/vladimir/.local/share/mise/installs/ruby/3.0.2/bin/ruby_executable_hooks:22:in `eval'
	from /home/vladimir/.local/share/mise/installs/ruby/3.0.2/bin/ruby_executable_hooks:22:in `<main>'
3.0.2 :013 > RbFFI.rb_raise rb_eException, "fatal"
/home/vladimir/.local/share/rtx/installs/ruby/3.0.2/lib/ruby/gems/3.0.0/gems/ffi-1.16.3/lib/ffi/variadic.rb:47:in `invoke': fatal (Exception)
	from /home/vladimir/.local/share/rtx/installs/ruby/3.0.2/lib/ruby/gems/3.0.0/gems/ffi-1.16.3/lib/ffi/variadic.rb:47:in `call'
	from /home/vladimir/.local/share/rtx/installs/ruby/3.0.2/lib/ruby/gems/3.0.0/gems/ffi-1.16.3/lib/ffi/variadic.rb:62:in `rb_raise'
	from (irb):13:in `<main>'
	from /home/vladimir/.local/share/rtx/installs/ruby/3.0.2/lib/ruby/gems/3.0.0/gems/irb-1.14.0/exe/irb:9:in `<top (required)>'
	from /home/vladimir/.local/share/mise/installs/ruby/3.0.2/bin/irb:25:in `load'
	from /home/vladimir/.local/share/mise/installs/ruby/3.0.2/bin/irb:25:in `<main>'
	from /home/vladimir/.local/share/mise/installs/ruby/3.0.2/bin/ruby_executable_hooks:22:in `eval'
	from /home/vladimir/.local/share/mise/installs/ruby/3.0.2/bin/ruby_executable_hooks:22:in `<main>'
3.0.2 :014 > RbFFI.attach_function :rb_fatal, [:string, :varargs], :void
 => #<FFI::VariadicInvoker:0x000058dfab66d170 @fixed=[#<FFI::Type::Builtin::STRING size=8 alignment=8>], @type_map=nil> 
3.0.2 :015 > RbFFI.rb_fatal "faaaaaaaaaaaaaaaaatal"
/home/vladimir/.local/share/rtx/installs/ruby/3.0.2/lib/ruby/gems/3.0.0/gems/ffi-1.16.3/lib/ffi/variadic.rb:47:in `invoke': faaaaaaaaaaaaaaaaatal (fatal)
	from /home/vladimir/.local/share/rtx/installs/ruby/3.0.2/lib/ruby/gems/3.0.0/gems/ffi-1.16.3/lib/ffi/variadic.rb:47:in `call'
	from /home/vladimir/.local/share/rtx/installs/ruby/3.0.2/lib/ruby/gems/3.0.0/gems/ffi-1.16.3/lib/ffi/variadic.rb:62:in `rb_fatal'
	from (irb):15:in `<top (required)>'
	from /home/vladimir/.local/share/rtx/installs/ruby/3.0.2/lib/ruby/gems/3.0.0/gems/irb-1.14.0/lib/irb/workspace.rb:121:in `eval'
	from /home/vladimir/.local/share/rtx/installs/ruby/3.0.2/lib/ruby/gems/3.0.0/gems/irb-1.14.0/lib/irb/workspace.rb:121:in `evaluate'
	from /home/vladimir/.local/share/rtx/installs/ruby/3.0.2/lib/ruby/gems/3.0.0/gems/irb-1.14.0/lib/irb/context.rb:633:in `evaluate_expression'
	from /home/vladimir/.local/share/rtx/installs/ruby/3.0.2/lib/ruby/gems/3.0.0/gems/irb-1.14.0/lib/irb/context.rb:601:in `evaluate'
	from /home/vladimir/.local/share/rtx/installs/ruby/3.0.2/lib/ruby/gems/3.0.0/gems/irb-1.14.0/lib/irb.rb:1049:in `block (2 levels) in eval_input'
	from /home/vladimir/.local/share/rtx/installs/ruby/3.0.2/lib/ruby/gems/3.0.0/gems/irb-1.14.0/lib/irb.rb:1388:in `signal_status'
	from /home/vladimir/.local/share/rtx/installs/ruby/3.0.2/lib/ruby/gems/3.0.0/gems/irb-1.14.0/lib/irb.rb:1041:in `block in eval_input'
	from /home/vladimir/.local/share/rtx/installs/ruby/3.0.2/lib/ruby/gems/3.0.0/gems/irb-1.14.0/lib/irb.rb:1120:in `block in each_top_level_statement'
	from /home/vladimir/.local/share/rtx/installs/ruby/3.0.2/lib/ruby/gems/3.0.0/gems/irb-1.14.0/lib/irb.rb:1117:in `loop'
	from /home/vladimir/.local/share/rtx/installs/ruby/3.0.2/lib/ruby/gems/3.0.0/gems/irb-1.14.0/lib/irb.rb:1117:in `each_top_level_statement'
	from /home/vladimir/.local/share/rtx/installs/ruby/3.0.2/lib/ruby/gems/3.0.0/gems/irb-1.14.0/lib/irb.rb:1040:in `eval_input'
	from /home/vladimir/.local/share/rtx/installs/ruby/3.0.2/lib/ruby/gems/3.0.0/gems/irb-1.14.0/lib/irb.rb:1021:in `block in run'
	from /home/vladimir/.local/share/rtx/installs/ruby/3.0.2/lib/ruby/gems/3.0.0/gems/irb-1.14.0/lib/irb.rb:1020:in `catch'
	from /home/vladimir/.local/share/rtx/installs/ruby/3.0.2/lib/ruby/gems/3.0.0/gems/irb-1.14.0/lib/irb.rb:1020:in `run'
	from /home/vladimir/.local/share/rtx/installs/ruby/3.0.2/lib/ruby/gems/3.0.0/gems/irb-1.14.0/lib/irb.rb:904:in `start'
	from /home/vladimir/.local/share/rtx/installs/ruby/3.0.2/lib/ruby/gems/3.0.0/gems/irb-1.14.0/exe/irb:9:in `<top (required)>'
	from /home/vladimir/.local/share/mise/installs/ruby/3.0.2/bin/irb:25:in `load'
	from /home/vladimir/.local/share/mise/installs/ruby/3.0.2/bin/irb:25:in `<main>'
	from /home/vladimir/.local/share/mise/installs/ruby/3.0.2/bin/ruby_executable_hooks:22:in `eval'
	from /home/vladimir/.local/share/mise/installs/ruby/3.0.2/bin/ruby_executable_hooks:22:in `<main>'
vladimir@np940x5n:~$ irb
3.0.2 :001 > require 'ffi'
 => true 
3.0.2 :002 > module RbFFI
3.0.2 :003 >   extend FFI::Library
3.0.2 :004 >   ffi_lib FFI::CURRENT_PROCESS
3.0.2 :005 > end
 => [#<FFI::DynamicLibrary:0x000060ee91216340 @name="[current process]">] 
3.0.2 :006 > RbFFI.attach_function :rb_fatal, [:string, :varargs], :void
 => #<FFI::VariadicInvoker:0x000060ee911b43c0 @fixed=[#<FFI::Type::Builtin::STRING size=8 alignment=8>], @type_map=nil> 
3.0.2 :007 > at_exit { puts 'byebye' }
 => #<Proc:0x000060ee9124ed08 (irb):7> 
3.0.2 :008 > RbFFI.rb_fatal "faaaaaaaaaaaaaaaaatal"
byebye
/home/vladimir/.local/share/rtx/installs/ruby/3.0.2/lib/ruby/gems/3.0.0/gems/ffi-1.16.3/lib/ffi/variadic.rb:47:in `invoke': faaaaaaaaaaaaaaaaatal (fatal)
	from /home/vladimir/.local/share/rtx/installs/ruby/3.0.2/lib/ruby/gems/3.0.0/gems/ffi-1.16.3/lib/ffi/variadic.rb:47:in `call'
	from /home/vladimir/.local/share/rtx/installs/ruby/3.0.2/lib/ruby/gems/3.0.0/gems/ffi-1.16.3/lib/ffi/variadic.rb:62:in `rb_fatal'
	from (irb):8:in `<top (required)>'
	from /home/vladimir/.local/share/rtx/installs/ruby/3.0.2/lib/ruby/gems/3.0.0/gems/irb-1.14.0/lib/irb/workspace.rb:121:in `eval'
	from /home/vladimir/.local/share/rtx/installs/ruby/3.0.2/lib/ruby/gems/3.0.0/gems/irb-1.14.0/lib/irb/workspace.rb:121:in `evaluate'
	from /home/vladimir/.local/share/rtx/installs/ruby/3.0.2/lib/ruby/gems/3.0.0/gems/irb-1.14.0/lib/irb/context.rb:633:in `evaluate_expression'
	from /home/vladimir/.local/share/rtx/installs/ruby/3.0.2/lib/ruby/gems/3.0.0/gems/irb-1.14.0/lib/irb/context.rb:601:in `evaluate'
	from /home/vladimir/.local/share/rtx/installs/ruby/3.0.2/lib/ruby/gems/3.0.0/gems/irb-1.14.0/lib/irb.rb:1049:in `block (2 levels) in eval_input'
	from /home/vladimir/.local/share/rtx/installs/ruby/3.0.2/lib/ruby/gems/3.0.0/gems/irb-1.14.0/lib/irb.rb:1388:in `signal_status'
	from /home/vladimir/.local/share/rtx/installs/ruby/3.0.2/lib/ruby/gems/3.0.0/gems/irb-1.14.0/lib/irb.rb:1041:in `block in eval_input'
	from /home/vladimir/.local/share/rtx/installs/ruby/3.0.2/lib/ruby/gems/3.0.0/gems/irb-1.14.0/lib/irb.rb:1120:in `block in each_top_level_statement'
	from /home/vladimir/.local/share/rtx/installs/ruby/3.0.2/lib/ruby/gems/3.0.0/gems/irb-1.14.0/lib/irb.rb:1117:in `loop'
	from /home/vladimir/.local/share/rtx/installs/ruby/3.0.2/lib/ruby/gems/3.0.0/gems/irb-1.14.0/lib/irb.rb:1117:in `each_top_level_statement'
	from /home/vladimir/.local/share/rtx/installs/ruby/3.0.2/lib/ruby/gems/3.0.0/gems/irb-1.14.0/lib/irb.rb:1040:in `eval_input'
	from /home/vladimir/.local/share/rtx/installs/ruby/3.0.2/lib/ruby/gems/3.0.0/gems/irb-1.14.0/lib/irb.rb:1021:in `block in run'
	from /home/vladimir/.local/share/rtx/installs/ruby/3.0.2/lib/ruby/gems/3.0.0/gems/irb-1.14.0/lib/irb.rb:1020:in `catch'
	from /home/vladimir/.local/share/rtx/installs/ruby/3.0.2/lib/ruby/gems/3.0.0/gems/irb-1.14.0/lib/irb.rb:1020:in `run'
	from /home/vladimir/.local/share/rtx/installs/ruby/3.0.2/lib/ruby/gems/3.0.0/gems/irb-1.14.0/lib/irb.rb:904:in `start'
	from /home/vladimir/.local/share/rtx/installs/ruby/3.0.2/lib/ruby/gems/3.0.0/gems/irb-1.14.0/exe/irb:9:in `<top (required)>'
	from /home/vladimir/.local/share/mise/installs/ruby/3.0.2/bin/irb:25:in `load'
	from /home/vladimir/.local/share/mise/installs/ruby/3.0.2/bin/irb:25:in `<main>'
	from /home/vladimir/.local/share/mise/installs/ruby/3.0.2/bin/ruby_executable_hooks:22:in `eval'
	from /home/vladimir/.local/share/mise/installs/ruby/3.0.2/bin/ruby_executable_hooks:22:in `<main>'
vladimir@np940x5n:~$

As you can see, rb_fatal is not the same as just using rb_throw with rb_eFatal, it cannot be rescued, but it's not the same as throwing unhandled C++ exception, although abort() is called in the end, some sort of cleanup is performed (when possible), and at_exit was called.

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Unhadled C++ exceptions cause abort #994

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Sunbelt Computer Software

PL/B Language Development and Support

Unhadled C++ exceptions cause abort #994

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uvlad7 commented on Sep 1, 2024

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