From: akr@...
Date: 2015-07-14T04:54:22+00:00
Subject: [ruby-core:69962] [Ruby trunk - Bug #11350] [Feedback] When Process.exec failed, redirections were still changed and not restored

Issue #11350 has been updated by Akira Tanaka.

Status changed from Open to Feedback

It is an example of the documented behavior described as follows.

```
 *  The modified attributes may be retained when <code>exec(2)</code> system
 *  call fails.
 *
 *  For example, hard resource limits are not restorable.
 *
 *  Consider to create a child process using ::spawn or Kernel#system if this
 *  is not acceptable.
```

It is possible to restore FDs if there are free FDs enough.
But It is a tired task.  

----------------------------------------
Bug #11350: When Process.exec failed, redirections were still changed and not restored
https://bugs.ruby-lang.org/issues/11350#change-53394

* Author: Naohisa Goto
* Status: Feedback
* Priority: Normal
* Assignee: Nobuyoshi Nakada
* ruby -v: 
* Backport: 2.0.0: UNKNOWN, 2.1: UNKNOWN, 2.2: UNKNOWN
----------------------------------------
When Process.exec failed, redirections of file descriptors were changed and not restored.

When redirecting fd 3 or 5, ASYNC BUG occurred as below.

~~~
$ ruby -e 'begin; Process.exec("/does_not_exist", "arg", { 3=>["/dev/null", "w"]}); rescue Errno::ENOENT => e; $stdout.print "stdout: ", e.inspect, "\n"; $stderr.print "stderr: ", e.inspect, "\n"; end'
[ASYNC BUG] consume_communication_pipe: read

EBADF

ruby 2.3.0dev (2015-07-13) [sparc64-solaris2.10]

[NOTE]
You may have encountered a bug in the Ruby interpreter or extension libraries.
Bug reports are welcome.
For details: http://www.ruby-lang.org/bugreport.html

stdout: #<Errno::ENOENT: No such file or directory - /does_not_exist>
stderr: #<Errno::ENOENT: No such file or directory - /does_not_exist>Abort
~~~

~~~
$ ruby -e 'begin; Process.exec("/does_not_exist", "arg", { 5=>["/dev/null", "w"]}); rescue Errno::ENOENT => e; $stdout.print "stdout: ", e.inspect, "\n"; $stderr.print "stderr: ", e.inspect, "\n"; end'
[ASYNC BUG] consume_communication_pipe: read

EBADF

ruby 2.3.0dev (2015-07-13) [sparc64-solaris2.10]

stdout: [NOTE]
You may have encountered a bug in the Ruby interpreter or extension libraries.
Bug reports are welcome.
For details: http://www.ruby-lang.org/bugreport.html

#<Errno::ENOENT: No such file or directory - /does_not_exist>
stderr: #<Errno::ENOENT: No such file or directory - /does_not_exist>Abort
~~~



When redirecting fd 1 or 2 to /dev/null, stdout or stderr is still redirected to /dev/null and the printed contents are not shown.

~~~
% ruby -e 'begin; Process.exec("/does_not_exist", "arg", { 1=>["/dev/null", "w"]}); rescue Errno::ENOENT => e; $stdout.print "stdout: ", e.inspect, "\n"; $stderr.print "stderr: ", e.inspect, "\n"; end'
stderr: #<Errno::ENOENT: No such file or directory - /does_not_exist>
~~~

~~~
% ruby -e 'begin; Process.exec("/does_not_exist", "arg", { 2=>["/dev/null", "w"]}); rescue Errno::ENOENT => e; $stdout.print "stdout: ", e.inspect, "\n"; $stderr.print "stderr: ", e.inspect, "\n"; end'
stdout: #<Errno::ENOENT: No such file or directory - /does_not_exist>
~~~

All of the above are observed both on x86_64 Linux and sparc Solaris.

Is this spec or bug?




-- 
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