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Bug #11269

ruby_init_setproctitle() should be called before require_libraries()

Added by apoikos (Apollon Oikonomopoulos) over 4 years ago. Updated over 4 years ago.

Status:
Assigned
Priority:
Normal
Target version:
-
ruby -v:
ruby 2.1.5p273
[ruby-core:69610]

Description

We have come across an issue where setproctitle fails to use the whole length of the process's initial environment. It turns out that this is because modules loaded using -r are processed before ruby_init_setproctitle(). This is easily reproducible using bundler, given the following test script under Linux:

File.open('/proc/self/cmdline') do |f|
  @argv_len = f.read.size
end

File.open('/proc/self/environ') do |f|
  @env_len = f.read.size
end

total = @argv_len + @env_len
$0 = 'a' * (total + 2) # should not overflow

File.open('/proc/self/environ') do |f|
  env = f.read
  puts env
  puts env.size
end

Calling the script directly, we see that setproctitle works correctly:

$ env -i A_VAR=some_value PATH=/bin:/usr/bin ruby test.rb 
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
36

In this case setproctitle correctly overwrites the whole environment space available. However, if we require bundler/setup (which is what bundle exec essentially does), the following happens:

$ env -i A_VAR=some_value PATH=/bin:/usr/bin ruby -rbundler/setup test.rb
aaaaaaaaaaaaaaaPATH=/bin:/usr/bin
36

This is because require 'bundler/setup' is processed before ruby_init_setproctitle() is called and attempts to manipulate PATH. While doing so, the new PATH string is allocated on the heap and the original pointer in environ replaced, thus breaking ruby_init_setproctitle()'s expectation to find a contiguous environment block.

Perhaps ruby_init_setproctitle() can be called before process_options(), so that it can process the environment block before a library gets a chance of modifying it.

History

Updated by kosaki (Motohiro KOSAKI) over 4 years ago

  • Status changed from Open to Assigned
  • Assignee set to kosaki (Motohiro KOSAKI)

I agree.
I'll take a look.

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