lib/libc_r/uthread/uthread_jmp.c

   1 /*
   2  * Copyright (C) 2000 Jason Evans <jasone@freebsd.org>.
   3  * All rights reserved.
   4  * Copyright (C) 2000 Daniel M. Eischen <eischen@vigrid.com>.
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice(s), this list of conditions and the following disclaimer as
  12  *    the first lines of this file unmodified other than the possible
  13  *    addition of one or more copyright notices.
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice(s), this list of conditions and the following disclaimer in
  16  *    the documentation and/or other materials provided with the
  17  *    distribution.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY
  20  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE
  23  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
  26  * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
  27  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
  28  * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
  29  * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  30  *
  31  * $FreeBSD: src/lib/libc_r/uthread/uthread_jmp.c,v 1.2.2.4 2002/10/22 14:44:03 fjoe Exp $
  32  * $DragonFly: src/lib/libc_r/uthread/uthread_jmp.c,v 1.3 2007/04/29 01:10:33 dillon Exp $
  33  */
  34
  35 #include <sys/user.h>   /* MUST BE FIRST */
  36 #include <unistd.h>
  37 #include <setjmp.h>
  38 #include <sys/param.h>
  39 #include <machine/reg.h>
  40 #include <pthread.h>
  41 #include "pthread_private.h"
  42
  43 /* Prototypes: */
  44 static inline int       check_stack(pthread_t thread, void *stackp);
  45
  46 void
  47 siglongjmp(sigjmp_buf env, int savemask)
  48 {
  49         struct pthread  *curthread = _get_curthread();
  50
  51         if (check_stack(curthread, (void *) GET_STACK_SJB(env)))
  52                 PANIC("siglongjmp()ing between thread contexts is undefined by "
  53                     "POSIX 1003.1");
  54
  55         /*
  56          * The stack pointer is somewhere within the threads stack.
  57          * Jump to the users context.
  58          */
  59         __siglongjmp(env, savemask);
  60 }
  61
  62 void
  63 longjmp(jmp_buf env, int val)
  64 {
  65         struct pthread  *curthread = _get_curthread();
  66
  67         if (check_stack(curthread, (void *) GET_STACK_JB(env)))
  68                 PANIC("longjmp()ing between thread contexts is undefined by "
  69                     "POSIX 1003.1");
  70
  71         /*
  72          * The stack pointer is somewhere within the threads stack.
  73          * Jump to the users context.
  74          */
  75         __longjmp(env, val);
  76 }
  77
  78 void
  79 _longjmp(jmp_buf env, int val)
  80 {
  81         struct pthread  *curthread = _get_curthread();
  82
  83         if (check_stack(curthread, (void *) GET_STACK_JB(env)))
  84                 PANIC("_longjmp()ing between thread contexts is undefined by "
  85                     "POSIX 1003.1");
  86
  87         /*
  88          * The stack pointer is somewhere within the threads stack.
  89          * Jump to the users context.
  90          */
  91         ___longjmp(env, val);
  92 }
  93
  94 /* Returns 0 if stack check is OK, non-zero otherwise. */
  95 static inline int
  96 check_stack(pthread_t thread, void *stackp)
  97 {
  98         void    *stack_begin, *stack_end;
  99
 100         /* Get the bounds of the current threads stack. */
 101         PTHREAD_ASSERT(thread->stack != NULL,
 102             "Thread stack pointer is null");
 103         stack_begin = thread->stack;
 104         stack_end = stack_begin + thread->attr.stacksize_attr;
 105
 106         /*
 107          * Make sure we aren't jumping to a different stack.  Make sure
 108          * jmp_stackp is between stack_begin and stack end, to correctly detect
 109          * this condition regardless of whether the stack grows up or down.
 110          */
 111         if (((stackp < stack_begin) && (stackp < stack_end)) ||
 112             ((stackp > stack_begin) && (stackp > stack_end)))
 113                 return (1);
 114         else
 115                 return (0);
 116 }