Rewritten. cvs/libc-960103

5 files changed, 78 insertions, 57 deletions

diff --git a/hurd/hurdsig.c b/hurd/hurdsig.c
index cecc415574..290dba825e 100644
--- a/hurd/hurdsig.c
+++ b/hurd/hurdsig.c
@@ -1,4 +1,4 @@
-/* Copyright (C) 1991, 1992, 1993, 1994, 1995 Free Software Foundation, Inc.
+/* Copyright (C) 1991, 92, 93, 94, 95, 96 Free Software Foundation, Inc.
 This file is part of the GNU C Library.
 
 The GNU C Library is free software; you can redistribute it and/or
@@ -74,10 +74,11 @@ _hurd_thread_sigstate (thread_t thread)
       ss->thread = thread;
       __spin_lock_init (&ss->lock);
 
-      /* Initialze default state.  */
+      /* Initialize default state.  */
       __sigemptyset (&ss->blocked);
       __sigemptyset (&ss->pending);
       memset (&ss->sigaltstack, 0, sizeof (ss->sigaltstack));
+      ss->preempters = NULL;
       ss->suspended = 0;
       ss->intr_port = MACH_PORT_NULL;
       ss->context = NULL;
@@ -231,6 +232,7 @@ interrupted_reply_port_location (struct machine_thread_all_state *thread_state,
   return portloc;
 }
 
+#include <hurd/sigpreempt.h>
 #include "intr-msg.h"
 
 /* SS->thread is suspended.
@@ -404,9 +406,8 @@ abort_all_rpcs (int signo, struct machine_thread_all_state *state, int live)
       }
 }
 
-
-struct hurd_signal_preempt *_hurd_signal_preempt[NSIG];
-struct mutex _hurd_signal_preempt_lock;
+struct hurd_signal_preempter *_hurdsig_preempters;
+sigset_t _hurdsig_preempted_set;
 
 /* Mask of stop signals.  */
 #define STOPSIGS (sigmask (SIGTTIN) | sigmask (SIGTTOU) | \
@@ -423,9 +424,8 @@ _hurd_internal_post_signal (struct hurd_sigstate *ss,
   error_t err;
   struct machine_thread_all_state thread_state;
   enum { stop, ignore, core, term, handle } act;
+  struct hurd_signal_preempter *pe;
   sighandler_t handler;
-  struct hurd_signal_preempt *pe;
-  sighandler_t (*preempt) (thread_t, int, long int, int) = NULL;
   sigset_t pending;
   int ss_suspended;
 
@@ -521,35 +521,37 @@ _hurd_internal_post_signal (struct hurd_sigstate *ss,
 
   thread_state.set = 0;		/* We know nothing.  */
 
-  /* Check for a preempted signal.  Preempted signals
-     can arrive during critical sections.  */
-  __mutex_lock (&_hurd_signal_preempt_lock);
-  for (pe = _hurd_signal_preempt[signo]; pe != NULL; pe = pe->next)
-    if (pe->handler && sigcode >= pe->first && sigcode <= pe->last)
-      {
-	preempt = pe->handler;
-	break;
-      }
-  __mutex_unlock (&_hurd_signal_preempt_lock);
+  __spin_lock (&ss->lock);
+
+  /* Check for a preempted signal.  Preempted signals can arrive during
+     critical sections.  */
 
-  handler = SIG_DFL;
-  if (preempt)
-    /* Let the preempting handler examine the thread.
-       If it returns SIG_DFL, we run the normal handler;
-       otherwise we use the handler it returns.  */
-    handler = (*preempt) (ss->thread, signo, sigcode, sigerror);
+  handler = SIG_ERR;
+  for (pe = ss->preempters; pe && handler == SIG_ERR; pe = pe->next)
+    if (HURD_PREEMPT_SIGNAL_P (pe, signo, sigcode))
+      handler = (*pe->preempter) (pe, ss, &signo, &sigcode, &sigerror);
+
+  if (handler == SIG_ERR && (__sigmask (signo) & _hurdsig_preempted_set))
+    {
+      __mutex_lock (&_hurd_siglock);
+      for (pe = _hurdsig_preempters; pe && handler == SIG_ERR; pe = pe->next)
+	if (HURD_PREEMPT_SIGNAL_P (pe, signo, sigcode))
+	  handler = (*pe->preempter) (pe, ss, &signo, &sigcode, &sigerror);
+      __mutex_unlock (&_hurd_siglock);
+    }
 
   ss_suspended = 0;
 
-  if (handler != SIG_DFL)
+  if (handler == SIG_IGN)
+    /* Ignore the signal altogether.  */
+    act = ignore;
+  if (handler != SIG_ERR)
     /* Run the preemption-provided handler.  */
     act = handle;
   else
     {
       /* No preemption.  Do normal handling.  */
 
-      __spin_lock (&ss->lock);
-
       if (!untraced && (_hurd_exec_flags & EXEC_TRACED))
 	{
 	  /* We are being traced.  Stop to tell the debugger of the signal.  */
diff --git a/sysdeps/generic/strsep.c b/sysdeps/generic/strsep.c
index bb4d68bd6e..b57a22f649 100644
--- a/sysdeps/generic/strsep.c
+++ b/sysdeps/generic/strsep.c
@@ -1,4 +1,4 @@
-/* Copyright (C) 1992, 1993 Free Software Foundation, Inc.
+/* Copyright (C) 1992, 1993, 1996 Free Software Foundation, Inc.
 This file is part of the GNU C Library.
 
 The GNU C Library is free software; you can redistribute it and/or
@@ -16,24 +16,28 @@ License along with the GNU C Library; see the file COPYING.LIB.  If
 not, write to the Free Software Foundation, Inc., 675 Mass Ave,
 Cambridge, MA 02139, USA.  */
 
-#include <ansidecl.h>
 #include <string.h>
 
 char *
-DEFUN(strsep, (stringp, delim),
-      char **stringp AND CONST char *delim)
+strsep (char **stringp, const char *delim)
 {
   char *begin, *end;
 
-  begin = *stringp + strspn (*stringp, delim);
-  end = *stringp + strcspn (*stringp, delim);
-
-  if (end == *stringp)
+  begin = *stringp;
+  if (! begin || *begin == '\0')
     return NULL;
 
-  if (*end != '\0')
-    *end++ = '\0';
-  *stringp = end;
+  /* Find the end of the token.  */
+  end = strpbrk (begin, delim);
+  if (end)
+    {
+      /* Terminate the token and advance *STRINGP past the delimiters.  */
+      *end++ = '\0';
+      *stringp = end + strspn (end, delim);
+    }
+  else
+    /* No more delimiters; this is the last token.  */
+    *stringp = NULL;
 
   return begin;
 }
diff --git a/sysdeps/mach/hurd/fork.c b/sysdeps/mach/hurd/fork.c
index 25279645ee..6fadb3d97d 100644
--- a/sysdeps/mach/hurd/fork.c
+++ b/sysdeps/mach/hurd/fork.c
@@ -1,4 +1,4 @@
-/* Copyright (C) 1994, 1995 Free Software Foundation, Inc.
+/* Copyright (C) 1994, 1995, 1996 Free Software Foundation, Inc.
 This file is part of the GNU C Library.
 
 The GNU C Library is free software; you can redistribute it and/or
@@ -121,7 +121,6 @@ __fork (void)
 	__spin_lock (&_hurd_ports[i].lock);
       ports_locked = 1;
 
-      *(volatile task_t *) &__mach_task_self_; /* XXX work around kernel bug */
 
       /* Stop all other threads while copying the address space,
 	 so nothing changes.  */
@@ -130,6 +129,25 @@ __fork (void)
         {
           stopped = 1;
 
+#define XXX_KERNEL_PAGE_FAULT_BUG /* XXX work around page fault bug in mk */
+
+#ifdef XXX_KERNEL_PAGE_FAULT_BUG
+	  /* Gag me with a pitchfork.
+	     The bug scenario is this:
+
+	     - The page containing __mach_task_self_ is paged out.
+	     - The signal thread was faulting on that page when we
+	       suspended it via proc_dostop.  It holds some lock, or set
+	       some busy bit, or somesuch.
+	     - Now this thread faults on that same page.
+	     - GRATUIOUS DEADLOCK
+
+	     We can break the deadlock by aborting the thread that faulted
+	     first, which if the bug happened was the signal thread because
+	     it is the only other thread and we just suspended it.
+	     */
+	  __thread_abort (_hurd_msgport_thread);
+#endif
 	  /* Create the child task.  It will inherit a copy of our memory.  */
 	  err = __task_create (__mach_task_self (), 1, &newtask);
         }
diff --git a/sysdeps/mach/hurd/jmp-unwind.c b/sysdeps/mach/hurd/jmp-unwind.c
index 822501f8e5..20ca5f8aa6 100644
--- a/sysdeps/mach/hurd/jmp-unwind.c
+++ b/sysdeps/mach/hurd/jmp-unwind.c
@@ -1,5 +1,5 @@
 /* _longjmp_unwind -- Clean up stack frames unwound by longjmp.  Hurd version.
-Copyright (C) 1995 Free Software Foundation, Inc.
+Copyright (C) 1995, 1996 Free Software Foundation, Inc.
 This file is part of the GNU C Library.
 
 The GNU C Library is free software; you can redistribute it and/or
@@ -18,8 +18,9 @@ not, write to the Free Software Foundation, Inc., 675 Mass Ave,
 Cambridge, MA 02139, USA.  */
 
 #include <setjmp.h>
-#include <hurd/signal.h>
 #include <hurd/userlink.h>
+#include <hurd/signal.h>
+#include <hurd/sigpreempt.h>
 #include <assert.h>
 
 
@@ -36,7 +37,6 @@ _longjmp_unwind (jmp_buf env, int val)
 {
   struct hurd_sigstate *ss = _hurd_self_sigstate ();
   struct hurd_userlink *link;
-  struct hurd_signal_preempter **p;
 
   /* All access to SS->active_resources must take place inside a critical
      section where signal handlers cannot run.  */
diff --git a/sysdeps/mach/hurd/setgid.c b/sysdeps/mach/hurd/setgid.c
index b2d9313307..ca493a4f7b 100644
--- a/sysdeps/mach/hurd/setgid.c
+++ b/sysdeps/mach/hurd/setgid.c
@@ -1,4 +1,4 @@
-/* Copyright (C) 1991, 1992, 1993, 1994, 1995 Free Software Foundation, Inc.
+/* Copyright (C) 1991, 92, 93, 94, 95, 96 Free Software Foundation, Inc.
 This file is part of the GNU C Library.
 
 The GNU C Library is free software; you can redistribute it and/or
@@ -46,21 +46,26 @@ DEFUN(__setgid, (gid), gid_t gid)
       gid_t *newgen, *newaux, auxbuf[2];
       size_t ngen, naux;
 
-      newaux = _hurd_id.aux.gids;
-      naux = _hurd_id.aux.ngids;
       if (_hurd_id.gen.ngids == 0)
 	{
 	  /* No effective gids now.  The new set will be just GID.  */
 	  newgen = &gid;
 	  ngen = 1;
 	}
-      else if (_hurd_id.gen.gids[0] == 0)
+      else
 	{
-	  /* We are root; set the effective, real, and saved to GID.  */
 	  _hurd_id.gen.gids[0] = gid;
 	  _hurd_id.valid = 0;
 	  newgen = _hurd_id.gen.gids;
 	  ngen = _hurd_id.gen.ngids;
+	}
+
+      newaux = _hurd_id.aux.gids;
+      naux = _hurd_id.aux.ngids;
+      if (_hurd_id.gen.nuids > 0 && _hurd_id.gen.uids[0] == 0)
+	{
+	  /* We are root; set the real and saved IDs too.  */
+	  _hurd_id.valid = 0;
 	  if (_hurd_id.aux.ngids < 2)
 	    {
 	      newaux = auxbuf;
@@ -68,20 +73,12 @@ DEFUN(__setgid, (gid), gid_t gid)
 	    }
 	  newaux[0] = newaux[1] = gid;
 	}
-      else
-	{
-	  /* We are not root; just change the effective GID.  */
-	  _hurd_id.gen.gids[0] = gid;
-	  _hurd_id.valid = 0;
-	  newgen = _hurd_id.gen.gids;
-	  ngen = _hurd_id.gen.ngids;
-	}
 
       err = __USEPORT (AUTH, __auth_makeauth
 		       (port, NULL, MACH_MSG_TYPE_COPY_SEND, 0,
+			_hurd_id.gen.uids, _hurd_id.gen.nuids,
+			_hurd_id.aux.uids, _hurd_id.aux.nuids,
 			newgen, ngen, newaux, naux,
-			_hurd_id.gen.gids, _hurd_id.gen.ngids,
-			_hurd_id.aux.gids, _hurd_id.aux.ngids,
 			&newauth));
     }
   __mutex_unlock (&_hurd_id.lock);