nptl/unwind.c

   1 /* Copyright (C) 2003 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Ulrich Drepper <drepper@redhat.com>
   4    and Richard Henderson <rth@redhat.com>, 2003.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, write to the Free
  18    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  19    02111-1307 USA.  */
  20
  21 #include <setjmp.h>
  22 #include <stdlib.h>
  23 #include "pthreadP.h"
  24
  25
  26 #ifdef HAVE_FORCED_UNWIND
  27
  28 static _Unwind_Reason_Code
  29 unwind_stop (int version, _Unwind_Action actions,
  30              _Unwind_Exception_Class exc_class,
  31              struct _Unwind_Exception *exc_obj,
  32              struct _Unwind_Context *context, void *stop_parameter)
  33 {
  34   struct pthread_unwind_buf *buf = stop_parameter;
  35
  36   /* Do longjmp if we're at "end of stack", aka "end of unwind data".
  37      We assume there are only C frame without unwind data in between
  38      here and the jmp_buf target.  Otherwise simply note that the CFA
  39      of a function is NOT within it's stack frame; it's the SP of the
  40      previous frame.  */
  41   if ((actions & _UA_END_OF_STACK)
  42       || ! _JMPBUF_UNWINDS  (buf->cancel_jmp_buf[0].jmp_buf,
  43                              _Unwind_GetCFA (context)))
  44     __libc_longjmp ((struct __jmp_buf_tag *) buf->cancel_jmp_buf, 1);
  45
  46   return _URC_NO_REASON;
  47 }
  48
  49
  50 static void
  51 unwind_cleanup (_Unwind_Reason_Code reason, struct _Unwind_Exception *exc)
  52 {
  53   /* Nothing to do.  */
  54 }
  55
  56 #endif  /* have forced unwind */
  57
  58
  59 void
  60 __cleanup_fct_attribute __attribute ((noreturn))
  61 __pthread_unwind (__pthread_unwind_buf_t *buf)
  62 {
  63   struct pthread_unwind_buf *ibuf = (struct pthread_unwind_buf *) buf;
  64   struct pthread *self = THREAD_SELF;
  65
  66   /* Handle the compatibility stuff first.  Execute all handlers
  67      registered with the old method.  We don't execute them in order,
  68      instead, they will run first.  */
  69   struct _pthread_cleanup_buffer *oldp = ibuf->priv.data.cleanup;
  70   struct _pthread_cleanup_buffer *curp = THREAD_GETMEM (self, cleanup);
  71
  72   if (curp != oldp)
  73     {
  74       do
  75         {
  76           /* Pointer to the next element.  */
  77           struct _pthread_cleanup_buffer *nextp = curp->__prev;
  78
  79           /* Call the handler.  */
  80           curp->__routine (curp->__arg);
  81
  82           /* To the next.  */
  83           curp = nextp;
  84         }
  85       while (curp != oldp);
  86
  87       /* Mark the current element as handled.  */
  88       THREAD_SETMEM (self, cleanup, curp);
  89     }
  90
  91 #ifdef HAVE_FORCED_UNWIND
  92   /* This is not a catchable exception, so don't provide any details about
  93      the exception type.  We do need to initialize the field though.  */
  94   THREAD_SETMEM (self, exc.exception_class, 0);
  95   THREAD_SETMEM (self, exc.exception_cleanup, unwind_cleanup);
  96
  97   _Unwind_ForcedUnwind (&self->exc, unwind_stop, ibuf);
  98 #else
  99   /* We simply jump to the registered setjmp buffer.  */
 100   __libc_longjmp ((struct __jmp_buf_tag *) ibuf->cancel_jmp_buf, 1);
 101 #endif
 102   /* NOTREACHED */
 103
 104   /* We better do not get here.  */
 105   abort ();
 106 }
 107
 108
 109 void
 110 __cleanup_fct_attribute __attribute ((noreturn))
 111 __pthread_unwind_next (__pthread_unwind_buf_t *buf)
 112 {
 113   struct pthread_unwind_buf *ibuf = (struct pthread_unwind_buf *) buf;
 114
 115   __pthread_unwind (ibuf->priv.data.prev);
 116 }