Bug #9928

Fiddle::TestHandle#test_NEXT fails on AIX due to unexported symbols of extension libraries

Added by ReiOdaira (Rei Odaira) almost 6 years ago. Updated 11 months ago.

Target version:
ruby -v:
ruby 2.2.0dev (2014-06-02 trunk 45270) [powerpc-aix7.1.0.0]


Fiddle::TestHandle#test_NEXT fails on AIX.

[ 4/21] Fiddle::TestHandle#test_NEXT = 0.00 s                         
  1) Error:
Fiddle::DLError: unknown symbol "Init_objspace"
    /ss/home/rayod/Dev/Contribution/ruby-trunk-blue1/test/fiddle/test_handle.rb:171:in `[]'
    /ss/home/rayod/Dev/Contribution/ruby-trunk-blue1/test/fiddle/test_handle.rb:171:in `rescue in test_NEXT'
    /ss/home/rayod/Dev/Contribution/ruby-trunk-blue1/test/fiddle/test_handle.rb:144:in `test_NEXT'

The reason for this is a little bit complicated. Fiddle::TestHandle#test_NEXT tests the behavior of RTLD_NEXT for dlsym(3). According to the manual, RTLD_NEXT of AIX should behave like that of BSD, so the following part in Fiddle::TestHandle#test_NEXT should succeed, but in fact it fails.

          # BSD
          require 'objspace'
          handle = Handle::NEXT
          refute_nil handle['Init_objspace']

The problem is that on AIX, Ruby's extension libraries do not export their symbols, because they are loaded not by dlopen(3)/dlsym(3) but by load(3). The build process on AIX only specifies Init_* functions as the entry points of the extension shared libraries. This means Init_objspace cannot be the search target of RTLD_NEXT, and the test above results in nil. (FYI, the symbols in the modules loaded by load(3) can be found by RTLD_NEXT if they are exported.)

One way to solve this is to somehow export the Init_objspace function. However, specifying -Wl,-bexpall does not export the entry points, so we need to specify -Wl,-bexpfull, which looks like overkill for just passing this test.

Fortunately, on AIX, test/fiddle/helper.rb creates and loads a dummy shared library,, which contains and exports strcpy and some other functions, so we can take advantage of it for testing RTLD_NEXT. That is, we can simply query strcpy to check whether or not RTLD_NEXT works correctly, as follows. The patch is attached.

          handle = Handle::NEXT
          refute_nil handle['strcpy']


test_NEXT_for_aix.patch (2.96 KB) test_NEXT_for_aix.patch ReiOdaira (Rei Odaira), 06/10/2014 08:00 PM

Related issues

Related to Ruby master - Bug #10384: Fiddle::DLError: unknown symbol "Init_objspace" during Fiddle::TestHandle#test_NEXT and Fiddle::TestHandle#test_static_sym on SolarisClosedActions

Also available in: Atom PDF