2 * Copyright 1999 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
32 * by blocking the SIGVTALRM, SIGPROF, and SIGALRM signals. This is
33 * based on the observation that most userland thread packages use one
34 * of these signals to support preemption.
44 typedef struct Struct_LockDflt {
51 lockdflt_acquire(void *lock)
53 LockDflt *l = (LockDflt *)lock;
56 sigprocmask(SIG_BLOCK, &l->lock_mask, &old_mask);
58 l->old_mask = old_mask;
63 lockdflt_create(void *context)
69 sigemptyset(&l->lock_mask);
70 sigaddset(&l->lock_mask, SIGVTALRM);
71 sigaddset(&l->lock_mask, SIGPROF);
72 sigaddset(&l->lock_mask, SIGALRM);
77 lockdflt_destroy(void *lock)
79 LockDflt *l = (LockDflt *)lock;
84 lockdflt_release(void *lock)
86 LockDflt *l = (LockDflt *)lock;
88 assert(l->depth >= 0);
90 sigprocmask(SIG_SETMASK, &l->old_mask, NULL);
96 dllockinit(NULL, lockdflt_create, lockdflt_acquire, lockdflt_acquire,
97 lockdflt_release, lockdflt_destroy, NULL);