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[glibc.git] / nptl / unwind.c
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1 /* Copyright (C) 2003-2015 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.
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.
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.
16 You should have received a copy of the GNU Lesser General Public
17 License along with the GNU C Library; if not, see
18 <http://www.gnu.org/licenses/>. */
20 #include <setjmp.h>
21 #include <stdio.h>
22 #include <stdlib.h>
23 #include <string.h>
24 #include <unistd.h>
25 #include "pthreadP.h"
26 #include <jmpbuf-unwind.h>
28 #ifdef HAVE_FORCED_UNWIND
30 #ifdef _STACK_GROWS_DOWN
31 # define FRAME_LEFT(frame, other, adj) \
32 ((uintptr_t) frame - adj >= (uintptr_t) other - adj)
33 #elif _STACK_GROWS_UP
34 # define FRAME_LEFT(frame, other, adj) \
35 ((uintptr_t) frame - adj <= (uintptr_t) other - adj)
36 #else
37 # error "Define either _STACK_GROWS_DOWN or _STACK_GROWS_UP"
38 #endif
40 static _Unwind_Reason_Code
41 unwind_stop (int version, _Unwind_Action actions,
42 _Unwind_Exception_Class exc_class,
43 struct _Unwind_Exception *exc_obj,
44 struct _Unwind_Context *context, void *stop_parameter)
46 struct pthread_unwind_buf *buf = stop_parameter;
47 struct pthread *self = THREAD_SELF;
48 struct _pthread_cleanup_buffer *curp = THREAD_GETMEM (self, cleanup);
49 int do_longjump = 0;
51 /* Adjust all pointers used in comparisons, so that top of thread's
52 stack is at the top of address space. Without that, things break
53 if stack is allocated above the main stack. */
54 uintptr_t adj = (uintptr_t) self->stackblock + self->stackblock_size;
56 /* Do longjmp if we're at "end of stack", aka "end of unwind data".
57 We assume there are only C frame without unwind data in between
58 here and the jmp_buf target. Otherwise simply note that the CFA
59 of a function is NOT within it's stack frame; it's the SP of the
60 previous frame. */
61 if ((actions & _UA_END_OF_STACK)
62 || ! _JMPBUF_CFA_UNWINDS_ADJ (buf->cancel_jmp_buf[0].jmp_buf, context,
63 adj))
64 do_longjump = 1;
66 if (__glibc_unlikely (curp != NULL))
68 /* Handle the compatibility stuff. Execute all handlers
69 registered with the old method which would be unwound by this
70 step. */
71 struct _pthread_cleanup_buffer *oldp = buf->priv.data.cleanup;
72 void *cfa = (void *) (_Unwind_Ptr) _Unwind_GetCFA (context);
74 if (curp != oldp && (do_longjump || FRAME_LEFT (cfa, curp, adj)))
78 /* Pointer to the next element. */
79 struct _pthread_cleanup_buffer *nextp = curp->__prev;
81 /* Call the handler. */
82 curp->__routine (curp->__arg);
84 /* To the next. */
85 curp = nextp;
87 while (curp != oldp
88 && (do_longjump || FRAME_LEFT (cfa, curp, adj)));
90 /* Mark the current element as handled. */
91 THREAD_SETMEM (self, cleanup, curp);
95 if (do_longjump)
96 __libc_unwind_longjmp ((struct __jmp_buf_tag *) buf->cancel_jmp_buf, 1);
98 return _URC_NO_REASON;
102 static void
103 unwind_cleanup (_Unwind_Reason_Code reason, struct _Unwind_Exception *exc)
105 /* When we get here a C++ catch block didn't rethrow the object. We
106 cannot handle this case and therefore abort. */
107 __libc_fatal ("FATAL: exception not rethrown\n");
110 #endif /* have forced unwind */
113 void
114 __cleanup_fct_attribute __attribute ((noreturn))
115 __pthread_unwind (__pthread_unwind_buf_t *buf)
117 struct pthread_unwind_buf *ibuf = (struct pthread_unwind_buf *) buf;
118 struct pthread *self = THREAD_SELF;
120 #ifdef HAVE_FORCED_UNWIND
121 /* This is not a catchable exception, so don't provide any details about
122 the exception type. We do need to initialize the field though. */
123 THREAD_SETMEM (self, exc.exception_class, 0);
124 THREAD_SETMEM (self, exc.exception_cleanup, &unwind_cleanup);
126 _Unwind_ForcedUnwind (&self->exc, unwind_stop, ibuf);
127 #else
128 /* Handle the compatibility stuff first. Execute all handlers
129 registered with the old method. We don't execute them in order,
130 instead, they will run first. */
131 struct _pthread_cleanup_buffer *oldp = ibuf->priv.data.cleanup;
132 struct _pthread_cleanup_buffer *curp = THREAD_GETMEM (self, cleanup);
134 if (curp != oldp)
138 /* Pointer to the next element. */
139 struct _pthread_cleanup_buffer *nextp = curp->__prev;
141 /* Call the handler. */
142 curp->__routine (curp->__arg);
144 /* To the next. */
145 curp = nextp;
147 while (curp != oldp);
149 /* Mark the current element as handled. */
150 THREAD_SETMEM (self, cleanup, curp);
153 /* We simply jump to the registered setjmp buffer. */
154 __libc_unwind_longjmp ((struct __jmp_buf_tag *) ibuf->cancel_jmp_buf, 1);
155 #endif
156 /* NOTREACHED */
158 /* We better do not get here. */
159 abort ();
161 hidden_def (__pthread_unwind)
164 void
165 __cleanup_fct_attribute __attribute ((noreturn))
166 __pthread_unwind_next (__pthread_unwind_buf_t *buf)
168 struct pthread_unwind_buf *ibuf = (struct pthread_unwind_buf *) buf;
170 __pthread_unwind ((__pthread_unwind_buf_t *) ibuf->priv.data.prev);
172 hidden_def (__pthread_unwind_next)