1999-11-18 Roland McGrath <roland@baalperazim.frob.com>

        * hurd/hurdsig.c (_hurdsig_init): If __hurd_threadvar_stack_mask is
        nonzero, use cthread_fork to create the signal thread.
        * hurd/msgportdemux.c (_hurd_msgport_receive): Initialize
        _hurd_msgport_thread here (to self).
        * sysdeps/mach/hurd/fork.c (__fork): When __hurd_sigthread_stack_end
        is zero, instead compute child signal thread's starting SP from parent
        signal thread's current SP and the threadvar_stack variables.
        * hurd/Versions (GLIBC_2.1.3): Add cthread_fork, cthread_detach.
        These are now referenced weakly by _hurdsig_init.

        * hurd/report-wait.c (_S_msg_report_wait): Fix typo:
        &_hurd_itimer_thread not &_hurd_msgport_thread.

1999-10-01  Roland McGrath  <roland@baalperazim.frob.com>

        * hurd/hurdfchdir.c (_hurd_change_directory_port_from_fd): Rewrite
        without HURD_DPORT_USE to clean up warnings.
        * hurd/dtable.c (get_dtable_port): Likewise.

        * hurd/hurdioctl.c (rectty_dtable): Renamed to install_ctty.
        (install_ctty): Do the changing of the cttyid port cell here, inside
        the critical section while we holding the dtable lock.
        (_hurd_setcttyid, tiocsctty, tiocnotty): Use that instead of changing
        the port cell and calling rectty_dtable.
        (_hurd_locked_install_cttyid): New function, split out of install_ctty.
        (install_ctty): Use it inside a critical section, with the lock held.
        * sysdeps/mach/hurd/setsid.c (__setsid): Use
        _hurd_locked_install_cttyid to effect the cttyid and dtable changes
        after proc_setsid, having held the dtable lock throughout.
        * hurd/dtable.c (ctty_new_pgrp): With the dtable lock held, check the
        cttyid port for null and bail out early if so.  The dtable lock
        serializes us after any cttyid change and its associated dtable update.

2 files changed, 42 insertions, 21 deletions

diff --git a/sysdeps/mach/hurd/fork.c b/sysdeps/mach/hurd/fork.c
index 3981ed2..b28f5cb 100644
--- a/sysdeps/mach/hurd/fork.c
+++ b/sysdeps/mach/hurd/fork.c
@@ -480,9 +480,27 @@ __fork (void)
 				    (natural_t *) &state, &statecount))
 	LOSE;
 #if STACK_GROWTH_UP
-      state.SP = __hurd_sigthread_stack_base;
+#define THREADVAR_SPACE (__hurd_threadvar_max \
+			 * sizeof *__hurd_sightread_variables)
+      if (__hurd_sigthread_stack_base == 0)
+	{
+	  state.SP &= __hurd_threadvar_stack_mask;
+	  state.SP += __hurd_threadvar_stack_offset + THREADVAR_SPACE;
+	}
+      else
+	state.SP = __hurd_sigthread_stack_base;
 #else
-      state.SP = __hurd_sigthread_stack_end;
+      if (__hurd_sigthread_stack_end == 0)
+	{
+	  /* The signal thread has a normal stack assigned by cthreads.
+	     The threadvar_stack variables conveniently tell us how
+	     to get to the highest address in the stack, just below
+	     the per-thread variables.  */
+	  state.SP &= __hurd_threadvar_stack_mask;
+	  state.SP += __hurd_threadvar_stack_offset;
+	}
+      else
+	state.SP = __hurd_sigthread_stack_end;
 #endif
       MACHINE_THREAD_STATE_SET_PC (&state,
 				   (unsigned long int) _hurd_msgport_receive);
diff --git a/sysdeps/mach/hurd/setsid.c b/sysdeps/mach/hurd/setsid.c
index 6653b81..a1e84b0 100644
--- a/sysdeps/mach/hurd/setsid.c
+++ b/sysdeps/mach/hurd/setsid.c
@@ -38,29 +38,32 @@ __setsid (void)
 
   /* Tell the proc server we want to start a new session.  */
   err = __USEPORT (PROC, __proc_setsid (port));
-  if (!err)
-    /* Punt our current ctty.  We hold the dtable lock from before the
-       proc_setsid call through clearing the cttyid port so that we can be
-       sure that it's been cleared by the time the signal thread attempts
-       to re-ctty the dtable in response to the pgrp change notification.  */
-    _hurd_port_set (&_hurd_ports[INIT_PORT_CTTYID], MACH_PORT_NULL);
+  if (err)
+    __mutex_unlock (&_hurd_dtable_lock);
+  else
+    {
+      /* Punt our current ctty, and update the dtable accordingly.  We hold
+	 the dtable lock from before the proc_setsid call through clearing
+	 the cttyid port and processing the dtable, so that we can be sure
+	 that it's all done by the time the signal thread processes the
+	 pgrp change notification.  */
+      _hurd_locked_install_cttyid (MACH_PORT_NULL);
 
-  __mutex_unlock (&_hurd_dtable_lock);
-
-  if (!err)
-    /* Synchronize with the signal thread to make sure we have
-       received and processed proc_newids before returning to the user.
-       This both updates _hurd_pgrp, and
-    */
-    while (_hurd_pids_changed_stamp == stamp)
-      {
+      /* Synchronize with the signal thread to make sure we have received
+	 and processed proc_newids before returning to the user.
+	 This is necessary to ensure that _hurd_pgrp (and thus the value
+	 returned by `getpgrp ()' in other threads) has been updated before
+	 we return.  */
+      while (_hurd_pids_changed_stamp == stamp)
+	{
 #ifdef noteven
-	/* XXX we have no need for a mutex, but cthreads demands one.  */
-	__condition_wait (&_hurd_pids_changed_sync, NULL);
+	  /* XXX we have no need for a mutex, but cthreads demands one.  */
+	  __condition_wait (&_hurd_pids_changed_sync, NULL);
 #else
-	__swtch_pri (0);
+	  __swtch_pri (0);
 #endif
-      }
+	}
+    }
 
   HURD_CRITICAL_END;