merges r20990 from trunk into ruby_1_9_1.

* io.c (rb_io_initialize): check fd validity.  [ruby-dev:36646]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_9_1@21041 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 2 insertions, 0 deletions

diff --git a/io.c b/io.c
index cd5de69f10..d157f8d83d 100644
--- a/io.c
+++ b/io.c
@@ -5898,6 +5898,7 @@ rb_io_initialize(int argc, VALUE *argv, VALUE io)
     int fd, fmode, oflags = O_RDONLY;
     convconfig_t convconfig;
     VALUE opt;
+    struct stat st;
 
     rb_secure(4);
 
@@ -5906,6 +5907,7 @@ rb_io_initialize(int argc, VALUE *argv, VALUE io)
     rb_io_extract_modeenc(&vmode, 0, opt, &oflags, &fmode, &convconfig);
 
     fd = NUM2INT(fnum);
+    if (fstat(fd, &st) == -1) rb_sys_fail(0);
     UPDATE_MAXFD(fd);
     if (NIL_P(vmode)) {
 #if defined(HAVE_FCNTL) && defined(F_GETFL)