Bug #9102: ObjectSpace.dump_all creates a FD without close-on-exec flag

• Status: Closed
• Assignee: -
• Target version: -
• ruby -v: ruby 2.1.0dev (2013-11-14 trunk 43675) [x86_64-linux]
• Backport: 1.9.3: UNKNOWN, 2.0.0: UNKNOWN

[akr (Akira Tanaka)]

I found test/objspace/test_objspace.rb creates a file descriptor without
O_CLOEXEC.

Ruby should create all file descriptors with close-on-exec since Ruby 2.0.0.
So, this behavior is a bug (on OS which supports O_CLOEXEC).

% strace -oz -f -e open ./ruby test/objspace/test_objspace.rb
Run options:

Running tests:

Finished tests in 3.411053s, 4.1043 tests/s, 18316.3380 assertions/s.
14 tests, 62478 assertions, 0 failures, 0 errors, 0 skips

ruby -v: ruby 2.1.0dev (2013-11-11 trunk 43646) [x86_64-linux]
% grep -v O_CLOEXEC z
9832 --- SIGCHLD (Child exited) @ 0 (0) ---
9836 --- SIGCHLD (Child exited) @ 0 (0) ---
9838 open("/tmp/rubyheapAk8lt8", O_RDWR|O_CREAT|O_EXCL, 0600) = 7
9840 --- SIGCHLD (Child exited) @ 0 (0) ---
9843 --- SIGCHLD (Child exited) @ 0 (0) ---
9847 --- SIGCHLD (Child exited) @ 0 (0) ---
% ./ruby -v
ruby 2.1.0dev (2013-11-11 trunk 43646) [x86_64-linux]

I think we cannot use mkstemp().

[akr (Akira Tanaka)]

• ruby -v changed from ruby 2.1.0dev (2013-11-11 trunk 43646) [x86_64-linux] to ruby 2.1.0dev (2013-11-14 trunk 43675) [x86_64-linux]

2013/11/11 akr (Akira Tanaka) [e-mail]:

Bug #9102: ObjectSpace.dump_all creates a FD without close-on-exec flag
https://bugs.ruby-lang.org/issues/9102

I think we cannot use mkstemp().

Another reason we should avoid mkstemp() is that it doesn't
respect TMPDIR environment variable.

It makes CI difficult to remove temporary files reliably.

It seems test/objspace/test_objspace.rb retains a temporary variable in /tmp.

% ./ruby test/objspace/test_objspace.rb
Run options:

Running tests:

Finished tests in 0.626708s, 22.3390 tests/s, 101369.4049
assertions/s.
14 tests, 63529 assertions, 0 failures, 0 errors, 0 skips

% ls /tmp/rubyheap*
/tmp/rubyheapIPCDjl

chkbuild (CI used by rubyci.org) sets TMPDIR to a unique directory
for each build to remove temporary files even if a test aborts.

But temporary files created by mkstemp() are not removable because
TMPDIR is not in effect.

Tanaka Akira

[nobu (Nobuyoshi Nakada)]

• Status changed from Open to Closed
• % Done changed from 0 to 100

This issue was solved with changeset r43679.
Akira, thank you for reporting this issue.
Your contribution to Ruby is greatly appreciated.
May Ruby be with you.

---

objspace_dump.c: refine output

• ext/objspace/objspace_dump.c (dump_output): allow IO object as
  output, and use Tempfile.create and return open file instead of
  mkstemp() and path name for :file output.
  [ruby-core:58266] [Bug #9102]
• test/objspace/test_objspace.rb (TestObjSpace#dump_my_heap_please):
  remove temporary output file.