1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21
22 /*
23 * Copyright 2008 Sun Microsystems, Inc. All rights reserved.
24 * Use is subject to license terms.
25 */
26
27 #pragma ident "%Z%%M% %I% %E% SMI"
28
29 #include "lint.h"
30 #include "thr_uberdata.h"
31 #include <dlfcn.h>
32
33 /*
34 * This is common code for sparc, sparcv9, and i386.
35 * The amd64 unwind code is vastly different from this.
36 * Look under the amd64-specific directory structure for details.
37 */
38
39 /*
40 * _ex_unwind() is provided by libC, but if libC is not loaded we
41 * need to call a local version of _ex_unwind() which does exactly
42 * the same thing except for calling C++ destructors.
43 */
44 extern void _ex_clnup_handler(void *, void (*)(void *));
45 extern void _ex_unwind_local(void);
46 #pragma unknown_control_flow(_ex_clnup_handler)
47 #pragma unknown_control_flow(_ex_unwind_local)
48
49 /*
50 * _t_cancel(fp):calls cleanup handlers if there are any in
51 * frame (fp), and calls _ex_unwind() to call
52 * destructors if libC has been linked.
53 *
54 * Control comes here from _thrp_unwind. Logically:
55 *
56 * _thrp_unwind: first arg = current fp;
57 * jump _t_cancel;
58 *
59 * We could have called _t_cancel(_getfp) from thr_exit()
60 * but _ex_unwind() also calls _t_cancel() and it does after
61 * poping out the two frames. If _ex_unwind() passes the current
62 * fp, then it will be invalid. For a caller of _thrp_unwind()
63 * it looks as if it is calling _t_cancel(fp).
64 *
65 * _t_cancel will eventually call _thrp_exit().
66 * It never returns from _t_cancel().
67 *
68 */
69 void
_t_cancel(void * fp)70 _t_cancel(void *fp)
71 {
72 ulwp_t *self = curthread;
73 __cleanup_t *head;
74 void (*fptr)(void (*func)(void *), void *arg);
75
76 /* Do this once per thread exit, not once per unwind frame */
77 if (self->ul_ex_unwind == NULL &&
78 (self->ul_ex_unwind = dlsym(RTLD_PROBE, "_ex_unwind")) == NULL)
79 self->ul_ex_unwind = (void *)-1;
80
81 if (self->ul_ex_unwind == (void *)-1)
82 fptr = NULL;
83 else
84 fptr = (void (*)())self->ul_ex_unwind;
85
86 if (fp == NULL) {
87 _thrp_exit();
88 thr_panic("_t_cancel(): _thrp_exit() returned");
89 }
90
91 if ((head = self->ul_clnup_hdr) != NULL && fp == head->fp) {
92 self->ul_clnup_hdr = head->next;
93 /* execute the cleanup handler */
94 _ex_clnup_handler(head->arg, head->func);
95 thr_panic("_t_cancel(): _ex_clnup_handler() returned");
96 }
97
98 if (fptr != NULL && self->ul_unwind) {
99 /* libC is loaded and thread is canceled, call libC version */
100 (*fptr)(_thrp_unwind, NULL);
101 thr_panic("_t_cancel(): _ex_unwind() returned");
102 } else if (head != NULL) {
103 /* libC not present, call local version */
104 _ex_unwind_local();
105 thr_panic("_t_cancel(): _ex_unwind_local() returned");
106 } else {
107 /* libC not present and no cleanup handlers, exit here */
108 _thrp_exit();
109 thr_panic("_t_cancel(): _thrp_exit() returned");
110 }
111 /* never returns here */
112 }
113