Throughout, remove "include <errno.h>" from files which already include

cygerrno.h.
* include/cygwin/config.h (__DYNAMIC_REENT__): Define.
* include/cygwin/version.h: Bump API minor version.
* cygwin.din: Export __getreent
* cygerrno.h: Include errno.h.  Fix places where _impure_ptr is used directly
to store the errno value.
* debug.cc (__set_errno): Ditto.
* errno.cc: Remove _RRENT_ONLY define to get errno.cc compiled.
* signal.cc: Rename _reent_clib to _REENT throughout.
* thread.h (reent_clib): Remove prototype.
* thread.cc (reent_clib): Rename reent_clib to __getreent.  Return _impure_ptr
until MTinterface is initialized.
(reent_winsup): Fix a possible SEGV when _r == NULL.  Return NULL instead.
* MTinterface::fixup_after_fork: Switch reent back to _impure_ptr to keep
signal handling running when fork is called from a thread other than the
mainthread.

1 files changed, 29 insertions, 6 deletions

diff --git a/winsup/cygwin/thread.cc b/winsup/cygwin/thread.cc
index ac7d4b8c0..60e94e794 100644
--- a/winsup/cygwin/thread.cc
+++ b/winsup/cygwin/thread.cc
@@ -45,16 +45,21 @@ details. */
 
 extern int threadsafe;
 
-struct _reent *
-_reent_clib ()
+extern "C" struct _reent *
+__getreent ()
 {
   struct __reent_t *_r =
     (struct __reent_t *) MT_INTERFACE->reent_key.get ();
 
-#ifdef _CYG_THREAD_FAILSAFE
   if (_r == 0)
-    system_printf ("local thread storage not inited");
+    {
+#ifdef _CYG_THREAD_FAILSAFE
+      system_printf ("local thread storage not inited");
 #endif
+      /* Return _impure_ptr as long as MTinterface is not initialized */
+      return _impure_ptr;
+    }
+
   return _r->_clib;
 }
 
@@ -64,10 +69,14 @@ _reent_winsup ()
   struct __reent_t *_r =
     (struct __reent_t *) MT_INTERFACE->reent_key.get ();
 
-#ifdef _CYG_THREAD_FAILSAFE
   if (_r == 0)
-    system_printf ("local thread storage not inited");
+    {
+#ifdef _CYG_THREAD_FAILSAFE
+      system_printf ("local thread storage not inited");
 #endif
+      return NULL;
+    }
+
   return _r->_winsup;
 }
 
@@ -212,6 +221,20 @@ MTinterface::fixup_after_fork (void)
 {
   pthread_key::fixup_after_fork ();
 
+#ifndef __SIGNALS_ARE_MULTITHREADED__
+  /* As long as the signal handling not multithreaded
+     switch reents storage back to _impure_ptr for the mainthread
+     to support fork from threads other than the mainthread */
+  struct _reent *reent_old = __getreent ();
+
+  if (reent_old && _impure_ptr != reent_old)
+    *_impure_ptr = *reent_old;
+  reents._clib = _impure_ptr;
+  reents._winsup = &winsup_reent;
+  winsup_reent._process_logmask = LOG_UPTO (LOG_DEBUG);
+  reent_key.set (&reents);
+#endif
+
   threadcount = 1;
   pthread::init_mainthread ();