Issue #12666 has been updated by Yui NARUSE.


George Koehler wrote:
> For both BSD and Linux, I want to suggest
> 
> ~~~ ruby
> when /bsd|dragonfly|linux/
>   libc_so = "libc.so"
>   libm_so = "libm.so"
> ~~~

It breaks FreeBSD.

```
irb(main):001:0> require"fiddle"
=> true
irb(main):002:0> Fiddle.dlopen("libc.so")
Fiddle::DLError: /usr/lib/libc.so: invalid file format
        from /home/naruse/local/ruby/lib/ruby/2.4.0/fiddle.rb:47:in `initialize'
        from /home/naruse/local/ruby/lib/ruby/2.4.0/fiddle.rb:47:in `new'
        from /home/naruse/local/ruby/lib/ruby/2.4.0/fiddle.rb:47:in `dlopen'
        from (irb):2
        from /home/naruse/local/ruby/bin/irb:11:in `<main>'
irb(main):003:0> Fiddle.dlopen("/lib/libc.so.7")
=> #<Fiddle::Handle:0x000008031a0300>
```

Why you guys breaks other platforms without checking.

----------------------------------------
Bug #12666: Fatal error: glibc detected an invalid stdio handle
https://bugs.ruby-lang.org/issues/12666#change-61997

* Author: Vit Ondruch
* Status: Open
* Priority: Normal
* Assignee: 
* Target version: 
* ruby -v: ruby 2.3.1p112 (2016-04-26 revision 54768) [powerpc64-linux]
* Backport: 2.1: UNKNOWN, 2.2: UNKNOWN, 2.3: UNKNOWN
----------------------------------------
During build of Ruby for Fedora on PPC64, there is reported following error:

```
Fiddle::TestImport#test_io = Fatal error: glibc detected an invalid stdio handle
uncommon.mk:612: recipe for target 'yes-test-almost' failed
make: *** [yes-test-almost] Aborted (core dumped)
```

and this is the analysis of one of glibc maintainers:

```
libio vtable verification fails because there are two copies of libc.so.6 in the process:

	0x00003fffb79413a8 - 0x00003fffb7941f78 is __libc_IO_vtables in /lib64/power8/libc.so.6
	0x00003fffb74213c0 - 0x00003fffb7421f90 is __libc_IO_vtables in /lib64/libc.so.6

IO.pipe refers to a vtable from a the first copy, but the fprintf called via libffi comes from the second copy.

The root cause is the Fiddle module loading libc.so.6 with an absolute path:

#0  __dlopen (file=0x20728280 "/lib64/libc.so.6", mode=257) at dlopen.c:75
#1  0x00003fffb748782c in rb_fiddle_handle_initialize (argc=<optimized out>, argv=<optimized out>, self=544821280) at handle.c:179

This comes from test/fiddle/helper.rb:

when /x86_64-linux/
  libc_so = "/lib64/libc.so.6"
  libm_so = "/lib64/libm.so.6"
when /linux/
  libdir = '/lib'
  case [0].pack('L!').size
  when 4
    # 32-bit ruby
    libdir = '/lib32' if File.directory? '/lib32'
  when 8
    # 64-bit ruby
    libdir = '/lib64' if File.directory? '/lib64'
  end
  libc_so = File.join(libdir, "libc.so.6")
  libm_so = File.join(libdir, "libm.so.6")

So the good news is that it's just a path.  I expect the fix looks like this:

when /linux/
  libc_so = "libc.so.6"
  libm_so = "libm.so.6"

(This replaces tehe x86_64-linux branch, too.)
```

Please also note that:

```
libio vtable verification is a new security hardening feature in Fedora 25.
```

To workaround this error, I am going to apply following patch to Fedora:

```
From 346e147ba6480839b87046e9a9efab0bf6ed3660 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?V=C3=ADt=20Ondruch?= <vondruch / redhat.com>
Date: Wed, 10 Aug 2016 17:35:48 +0200
Subject: [PATCH] Rely on ldd to detect glibc.

This is just workaround, since we know we are quite sure this will be successful
on Red Hat platforms.

This workaround rhbz#1361037
---
 test/fiddle/helper.rb | 92 ---------------------------------------------------
 1 file changed, 92 deletions(-)

diff --git a/test/fiddle/helper.rb b/test/fiddle/helper.rb
index 1da3d93..65148a1 100644
--- a/test/fiddle/helper.rb
+++ b/test/fiddle/helper.rb
@@ -6,98 +6,6 @@
 
 libc_so = libm_so = nil
 
-case RUBY_PLATFORM
-when /cygwin/
-  libc_so = "cygwin1.dll"
-  libm_so = "cygwin1.dll"
-when /x86_64-linux/
-  libc_so = "/lib64/libc.so.6"
-  libm_so = "/lib64/libm.so.6"
-when /linux/
-  libdir = '/lib'
-  case [0].pack('L!').size
-  when 4
-    # 32-bit ruby
-    libdir = '/lib32' if File.directory? '/lib32'
-  when 8
-    # 64-bit ruby
-    libdir = '/lib64' if File.directory? '/lib64'
-  end
-  libc_so = File.join(libdir, "libc.so.6")
-  libm_so = File.join(libdir, "libm.so.6")
-when /mingw/, /mswin/
-  require "rbconfig"
-  crtname = RbConfig::CONFIG["RUBY_SO_NAME"][/msvc\w+/] || 'ucrtbase'
-  libc_so = libm_so = "#{crtname}.dll"
-when /darwin/
-  libc_so = "/usr/lib/libc.dylib"
-  libm_so = "/usr/lib/libm.dylib"
-when /kfreebsd/
-  libc_so = "/lib/libc.so.0.1"
-  libm_so = "/lib/libm.so.1"
-when /gnu/	#GNU/Hurd
-  libc_so = "/lib/libc.so.0.3"
-  libm_so = "/lib/libm.so.6"
-when /mirbsd/
-  libc_so = "/usr/lib/libc.so.41.10"
-  libm_so = "/usr/lib/libm.so.7.0"
-when /freebsd/
-  libc_so = "/lib/libc.so.7"
-  libm_so = "/lib/libm.so.5"
-when /bsd|dragonfly/
-  libc_so = "/usr/lib/libc.so"
-  libm_so = "/usr/lib/libm.so"
-when /solaris/
-  libdir = '/lib'
-  case [0].pack('L!').size
-  when 4
-    # 32-bit ruby
-    libdir = '/lib' if File.directory? '/lib'
-  when 8
-    # 64-bit ruby
-    libdir = '/lib/64' if File.directory? '/lib/64'
-  end
-  libc_so = File.join(libdir, "libc.so")
-  libm_so = File.join(libdir, "libm.so")
-when /aix/
-  pwd=Dir.pwd
-  libc_so = libm_so = "#{pwd}/libaixdltest.so"
-  unless File.exist? libc_so
-    cobjs=%w!strcpy.o!
-    mobjs=%w!floats.o sin.o!
-    funcs=%w!sin sinf strcpy strncpy!
-    expfile='dltest.exp'
-    require 'tmpdir'
-    Dir.mktmpdir do |dir|
-      begin
-        Dir.chdir dir
-        %x!/usr/bin/ar x /usr/lib/libc.a #{cobjs.join(' ')}!
-        %x!/usr/bin/ar x /usr/lib/libm.a #{mobjs.join(' ')}!
-        %x!echo "#{funcs.join("\n")}\n" > #{expfile}!
-        require 'rbconfig'
-        if RbConfig::CONFIG["GCC"] = 'yes'
-          lflag='-Wl,'
-        else
-          lflag=''
-        end
-        flags="#{lflag}-bE:#{expfile} #{lflag}-bnoentry -lm"
-        %x!#{RbConfig::CONFIG["LDSHARED"]} -o #{libc_so} #{(cobjs+mobjs).join(' ')} #{flags}!
-      ensure
-        Dir.chdir pwd
-      end
-    end
-  end
-else
-  libc_so = ARGV[0] if ARGV[0] && ARGV[0][0] == ?/
-  libm_so = ARGV[1] if ARGV[1] && ARGV[1][0] == ?/
-  if( !(libc_so && libm_so) )
-    $stderr.puts("libc and libm not found: #{$0} <libc> <libm>")
-  end
-end
-
-libc_so = nil if !libc_so || (libc_so[0] == ?/ && !File.file?(libc_so))
-libm_so = nil if !libm_so || (libm_so[0] == ?/ && !File.file?(libm_so))
-
 if !libc_so || !libm_so
   ruby = EnvUtil.rubybin
   ldd = `ldd #{ruby}`
-- 
2.9.2
```

i.e. I am going to disable the custom code for detecting glibc on various platfors and rely just on ldd. My question is what should be the proper fix? Shouldn't be the ldd way the default behavior for Linux?

This issue was originally reported at:

https://bugzilla.redhat.com/show_bug.cgi?id=1361037




---Files--------------------------------
fiddle-path.diff (1.37 KB)


-- 
https://bugs.ruby-lang.org/

Unsubscribe: <mailto:ruby-core-request / ruby-lang.org?subject=unsubscribe>
<http://lists.ruby-lang.org/cgi-bin/mailman/options/ruby-core>