* io.c (io_fread, io_getpartial, rb_io_sysread): set buffer size

  after check if readable, which can cause thread switch.
  [ruby-dev:45297][Bug #6099]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@34846 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

3 files changed, 44 insertions, 0 deletions

diff --git a/ChangeLog b/ChangeLog
index a5c5e8bf8d..832e53d2d9 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Tue Feb 28 18:33:30 2012  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* io.c (io_fread, io_getpartial, rb_io_sysread): set buffer size
+	  after check if readable, which can cause thread switch.
+	  [ruby-dev:45297][Bug #6099]
+
 Tue Feb 28 17:16:01 2012  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* lib/time.rb (Time#xmlschema): use strftime specifiers instead of
diff --git a/io.c b/io.c
index f6375cd8db..15b714560e 100644
--- a/io.c
+++ b/io.c
@@ -1872,11 +1872,14 @@ io_bufread(char *ptr, long len, rb_io_t *fptr)
     return len - n;
 }
 
+static void io_setstrbuf(VALUE *str, long len);
+
 static long
 io_fread(VALUE str, long offset, long size, rb_io_t *fptr)
 {
     long len;
 
+    io_setstrbuf(&str, offset + size);
     rb_str_locktmp(str);
     len = io_bufread(RSTRING_PTR(str) + offset, size, fptr);
     rb_str_unlocktmp(str);
@@ -2208,6 +2211,7 @@ io_getpartial(int argc, VALUE *argv, VALUE io, int nonblock)
         if (nonblock) {
             rb_io_set_nonblock(fptr);
         }
+	io_setstrbuf(&str, len);
 	rb_str_locktmp(str);
 	n = rb_read_internal(fptr->fd, RSTRING_PTR(str), len);
 	rb_str_unlocktmp(str);
@@ -4269,6 +4273,7 @@ rb_io_sysread(int argc, VALUE *argv, VALUE io)
     rb_thread_wait_fd(fptr->fd);
     rb_io_check_closed(fptr);
 
+    io_setstrbuf(&str, ilen);
     rb_str_locktmp(str);
     n = rb_read_internal(fptr->fd, RSTRING_PTR(str), ilen);
     rb_str_unlocktmp(str);
diff --git a/test/ruby/test_io.rb b/test/ruby/test_io.rb
index ebddf14d5e..11f8097479 100644
--- a/test/ruby/test_io.rb
+++ b/test/ruby/test_io.rb
@@ -2240,4 +2240,37 @@ End
     assert_equal(1, $stdout.fileno)
     assert_equal(2, $stderr.fileno)
   end
+
+  def test_sysread_locktmp
+    bug6099 = '[ruby-dev:45297]'
+    buf = " " * 100
+    data = "a" * 100
+    with_pipe do |r,w|
+      th = Thread.new {r.sysread(100, buf)}
+      Thread.pass until th.stop?
+      buf.replace("")
+      assert_empty(buf)
+      w.write(data)
+      Thread.pass while th.alive?
+      th.join
+    end
+    assert_equal(data, buf)
+  end
+
+  def test_readpartial_locktmp
+    bug6099 = '[ruby-dev:45297]'
+    buf = " " * 100
+    data = "a" * 100
+    with_pipe do |r,w|
+      r.fcntl(Fcntl::F_SETFL, Fcntl::O_NONBLOCK)
+      th = Thread.new {r.readpartial(100, buf)}
+      Thread.pass until th.stop?
+      buf.replace("")
+      assert_empty(buf)
+      w.write(data)
+      Thread.pass while th.alive?
+      th.join
+    end
+    assert_equal(data, buf)
+  end
 end