bpo-26732: fix too many fds in processes started with the "forkserver" method (#2813)

* bpo-26732: fix too many fds in processes started with the "forkserver" method

A child process would inherit as many fds as the number of still-running children.

* Add blurb and test comment

1 files changed, 1 insertions, 31 deletions

diff --git a/Lib/test/libregrtest/refleak.py b/Lib/test/libregrtest/refleak.py
index 8e93816..efe5210 100644
--- a/Lib/test/libregrtest/refleak.py
+++ b/Lib/test/libregrtest/refleak.py
@@ -7,36 +7,6 @@ from inspect import isabstract
 from test import support
 
 
-try:
-    MAXFD = os.sysconf("SC_OPEN_MAX")
-except Exception:
-    MAXFD = 256
-
-
-def fd_count():
-    """Count the number of open file descriptors"""
-    if sys.platform.startswith(('linux', 'freebsd')):
-        try:
-            names = os.listdir("/proc/self/fd")
-            return len(names)
-        except FileNotFoundError:
-            pass
-
-    count = 0
-    for fd in range(MAXFD):
-        try:
-            # Prefer dup() over fstat(). fstat() can require input/output
-            # whereas dup() doesn't.
-            fd2 = os.dup(fd)
-        except OSError as e:
-            if e.errno != errno.EBADF:
-                raise
-        else:
-            os.close(fd2)
-            count += 1
-    return count
-
-
 def dash_R(the_module, test, indirect_test, huntrleaks):
     """Run a test multiple times, looking for reference leaks.
 
@@ -174,7 +144,7 @@ def dash_R_cleanup(fs, ps, pic, zdc, abcs):
     func1 = sys.getallocatedblocks
     func2 = sys.gettotalrefcount
     gc.collect()
-    return func1(), func2(), fd_count()
+    return func1(), func2(), support.fd_count()
 
 
 def clear_caches():