2 * Copyright 1999, 2000 John D. Polstra.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
15 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
16 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
17 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
18 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
19 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
20 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
21 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
23 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 * Default thread locking implementation for the dynamic linker. It
30 * is used until the client registers a different implementation with
31 * dllockinit(). The default implementation does mutual exclusion by
32 * blocking almost all signals. This is based on the observation that
33 * most userland thread packages use signals to support preemption.
43 typedef struct Struct_LockDflt {
50 lockdflt_acquire(void *lock)
52 LockDflt *l = (LockDflt *)lock;
53 sigprocmask(SIG_BLOCK, &l->lock_mask, &l->old_mask);
54 assert(l->depth == 0);
59 lockdflt_create(void *context)
65 sigfillset(&l->lock_mask);
66 sigdelset(&l->lock_mask, SIGTRAP);
67 sigdelset(&l->lock_mask, SIGABRT);
68 sigdelset(&l->lock_mask, SIGBUS);
69 sigdelset(&l->lock_mask, SIGSEGV);
70 sigdelset(&l->lock_mask, SIGKILL);
71 sigdelset(&l->lock_mask, SIGSTOP);
76 lockdflt_destroy(void *lock)
78 LockDflt *l = (LockDflt *)lock;
83 lockdflt_release(void *lock)
85 LockDflt *l = (LockDflt *)lock;
86 assert(l->depth == 1);
88 sigprocmask(SIG_SETMASK, &l->old_mask, NULL);