1/* Copyright (C) 2003-2020 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, see
18 <https://www.gnu.org/licenses/>. */
19
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>
27
28#ifdef _STACK_GROWS_DOWN
29# define FRAME_LEFT(frame, other, adj) \
30 ((uintptr_t) frame - adj >= (uintptr_t) other - adj)
31#elif _STACK_GROWS_UP
32# define FRAME_LEFT(frame, other, adj) \
33 ((uintptr_t) frame - adj <= (uintptr_t) other - adj)
34#else
35# error "Define either _STACK_GROWS_DOWN or _STACK_GROWS_UP"
36#endif
37
38static _Unwind_Reason_Code
39unwind_stop (int version, _Unwind_Action actions,
40 _Unwind_Exception_Class exc_class,
41 struct _Unwind_Exception *exc_obj,
42 struct _Unwind_Context *context, void *stop_parameter)
43{
44 struct pthread_unwind_buf *buf = stop_parameter;
45 struct pthread *self = THREAD_SELF;
46 struct _pthread_cleanup_buffer *curp = THREAD_GETMEM (self, cleanup);
47 int do_longjump = 0;
48
49 /* Adjust all pointers used in comparisons, so that top of thread's
50 stack is at the top of address space. Without that, things break
51 if stack is allocated above the main stack. */
52 uintptr_t adj = (uintptr_t) self->stackblock + self->stackblock_size;
53
54 /* Do longjmp if we're at "end of stack", aka "end of unwind data".
55 We assume there are only C frame without unwind data in between
56 here and the jmp_buf target. Otherwise simply note that the CFA
57 of a function is NOT within it's stack frame; it's the SP of the
58 previous frame. */
59 if ((actions & _UA_END_OF_STACK)
60 || ! _JMPBUF_CFA_UNWINDS_ADJ (buf->cancel_jmp_buf[0].jmp_buf, context,
61 adj))
62 do_longjump = 1;
63
64 if (__glibc_unlikely (curp != NULL))
65 {
66 /* Handle the compatibility stuff. Execute all handlers
67 registered with the old method which would be unwound by this
68 step. */
69 struct _pthread_cleanup_buffer *oldp = buf->priv.data.cleanup;
70 void *cfa = (void *) (_Unwind_Ptr) _Unwind_GetCFA (context);
71
72 if (curp != oldp && (do_longjump || FRAME_LEFT (cfa, curp, adj)))
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 && (do_longjump || FRAME_LEFT (cfa, curp, adj)));
87
88 /* Mark the current element as handled. */
89 THREAD_SETMEM (self, cleanup, curp);
90 }
91 }
92
93 if (do_longjump)
94 __libc_unwind_longjmp ((struct __jmp_buf_tag *) buf->cancel_jmp_buf, 1);
95
96 return _URC_NO_REASON;
97}
98
99
100static void
101unwind_cleanup (_Unwind_Reason_Code reason, struct _Unwind_Exception *exc)
102{
103 /* When we get here a C++ catch block didn't rethrow the object. We
104 cannot handle this case and therefore abort. */
105 __libc_fatal ("FATAL: exception not rethrown\n");
106}
107
108
109void
110__cleanup_fct_attribute __attribute ((noreturn))
111__pthread_unwind (__pthread_unwind_buf_t *buf)
112{
113 struct pthread_unwind_buf *ibuf = (struct pthread_unwind_buf *) buf;
114 struct pthread *self = THREAD_SELF;
115
116 /* This is not a catchable exception, so don't provide any details about
117 the exception type. We do need to initialize the field though. */
118 THREAD_SETMEM (self, exc.exception_class, 0);
119 THREAD_SETMEM (self, exc.exception_cleanup, &unwind_cleanup);
120
121 _Unwind_ForcedUnwind (&self->exc, unwind_stop, ibuf);
122 /* NOTREACHED */
123
124 /* We better do not get here. */
125 abort ();
126}
127hidden_def (__pthread_unwind)
128
129
130void
131__cleanup_fct_attribute __attribute ((noreturn))
132__pthread_unwind_next (__pthread_unwind_buf_t *buf)
133{
134 struct pthread_unwind_buf *ibuf = (struct pthread_unwind_buf *) buf;
135
136 __pthread_unwind ((__pthread_unwind_buf_t *) ibuf->priv.data.prev);
137}
138hidden_def (__pthread_unwind_next)
139