Bug #3341: Random#randにTimeのRangeを渡すとSEGVする

• Status: Closed
• Assignee: nobu (Nobuyoshi Nakada)
• Target version: 1.9.2
• ruby -v: ruby 1.9.3dev (2010-05-25 trunk 28010) [x86_64-linux]

[ryoqun (Ryo Onodera)]

=begin
下の様なコマンドでSEGVします。Time.nowである必要はなくて、とにかくTimeなら何でも落ちます。

$ ruby -e 'Random.new.rand(Time.now..Time.now)'
-e:1: [BUG] Segmentation fault
ruby 1.9.3dev (2010-05-25 trunk 28010) [x86_64-linux]

-- control frame ----------
c:0004 p:---- s:0010 b:0010 l:000009 d:000009 CFUNC :(null)
c:0003 p:0053 s:0006 b:0006 l:000978 d:001638 EVAL -e:1
c:0002 p:---- s:0004 b:0004 l:000003 d:000003 FINISH
c:0001 p:0000 s:0002 b:0002 l:000978 d:000978 TOP

-- Ruby level backtrace information ----------------------------------------
-e:1:in `'
Segmentation fault
=end

[znz (Kazuhiro NISHIYAMA)]

=begin
range.end - range.begin が Float なら落ちるようで
ruby-trunk -e ';x=Object.new; def x.-(o);1.1;end; Random.new.rand(x..x)'
でも落ちました。

random_rand で

• v = range_values(vmax, &beg, &excl) が Time.now-Time.now で Float になる
• (vがgenrand_real2(&rnd->mt)をかけたものになる)
• RFLOAT_VALUE(rb_check_to_float(beg)); で beg が Time なので RFLOAT_VALUE(nil) になって落ちる
  という流れのようなので、以下のパッチのように単純に beg + v にした方が
  Random.new.rand(Time.at(0)..Time.now)
  のような使い方も出来て良いのではないでしょうか?

diff --git a/random.c b/random.c
index b2abca7..17cdf49 100644
--- a/random.c
+++ b/random.c
@@ -1074,15 +1074,7 @@ random_rand(int argc, VALUE *argv, VALUE obj)
long x = FIX2LONG(beg) + FIX2LONG(v);
return LONG2NUM(x);
}

• switch (TYPE(v)) {

•  case T_BIGNUM:
  

• return rb_big_plus(v, beg);

•  case T_FLOAT:
  

• RFLOAT_VALUE(v) += RFLOAT_VALUE(rb_check_to_float(beg));
• return v;

•  default:
  

• return rb_funcall2(v, id_plus, 1, &beg);
• }

• return rb_funcall2(beg, id_plus, 1, &v);
  }

/*

=end

[mrkn (Kenta Murata)]

• Status changed from Open to Assigned
• Assignee set to nobu (Nobuyoshi Nakada)

=begin

=end

[nobu (Nobuyoshi Nakada)]

• Status changed from Assigned to Closed

=begin
This issue was solved with changeset r28018.
Ryo, thank you for reporting this issue.
Your contribution to Ruby is greatly appreciated.
May Ruby be with you.

=end

[nobu (Nobuyoshi Nakada)]

• Category set to core
• Target version set to 1.9.2

=begin

=end