2 This file is part of PulseAudio.
4 Copyright 2009 Lennart Poettering
6 PulseAudio is free software; you can redistribute it and/or modify
7 it under the terms of the GNU Lesser General Public License as
8 published by the Free Software Foundation; either version 2.1 of the
9 License, or (at your option) any later version.
11 PulseAudio is distributed in the hope that it will be useful, but
12 WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 General Public License for more details.
16 You should have received a copy of the GNU Lesser General Public
17 License along with PulseAudio; if not, write to the Free Software
18 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
29 /* This is deprecated on glibc but is still used by FreeBSD */
30 #if !defined(MAP_ANONYMOUS) && defined(MAP_ANON)
31 # define MAP_ANONYMOUS MAP_ANON
34 #include <pulse/xmalloc.h>
36 #include <pulsecore/core-util.h>
37 #include <pulsecore/aupdate.h>
38 #include <pulsecore/atomic.h>
39 #include <pulsecore/once.h>
40 #include <pulsecore/mutex.h>
48 pa_memtrap *next[2], *prev[2];
51 static pa_memtrap *memtraps[2] = { NULL, NULL };
52 static pa_aupdate *aupdate;
53 static pa_static_mutex mutex = PA_STATIC_MUTEX_INIT; /* only required to serialize access to the write side */
55 static void allocate_aupdate(void) {
57 aupdate = pa_aupdate_new();
61 pa_bool_t pa_memtrap_is_good(pa_memtrap *m) {
64 return !pa_atomic_load(&m->bad);
67 static void sigsafe_error(const char *s) {
68 (void) write(STDERR_FILENO, s, strlen(s));
71 static void signal_handler(int sig, siginfo_t* si, void *data) {
76 j = pa_aupdate_read_begin(aupdate);
78 for (m = memtraps[j]; m; m = m->next[j])
79 if (si->si_addr >= m->start &&
80 (uint8_t*) si->si_addr < (uint8_t*) m->start + m->size)
86 pa_atomic_store(&m->bad, 1);
88 /* Remap anonymous memory into the bad segment */
89 if ((r = mmap(m->start, m->size, PROT_READ|PROT_WRITE, MAP_ANONYMOUS|MAP_FIXED|MAP_PRIVATE, -1, 0)) == MAP_FAILED) {
90 sigsafe_error("mmap() failed.\n");
94 pa_assert(r == m->start);
96 pa_aupdate_read_end(aupdate);
100 pa_aupdate_read_end(aupdate);
102 sigsafe_error("Failed to handle SIGBUS.\n");
106 static void memtrap_link(pa_memtrap *m, unsigned j) {
110 m->next[j] = memtraps[j];
114 static void memtrap_unlink(pa_memtrap *m, unsigned j) {
118 m->next[j]->prev[j] = m->prev[j];
121 m->prev[j]->next[j] = m->next[j];
123 memtraps[j] = m->next[j];
126 pa_memtrap* pa_memtrap_add(const void *start, size_t size) {
127 pa_memtrap *m = NULL;
134 start = PA_PAGE_ALIGN_PTR(start);
135 size = PA_PAGE_ALIGN(size);
137 m = pa_xnew(pa_memtrap, 1);
138 m->start = (void*) start;
140 pa_atomic_store(&m->bad, 0);
144 mx = pa_static_mutex_get(&mutex, FALSE, TRUE);
147 j = pa_aupdate_write_begin(aupdate);
149 j = pa_aupdate_write_swap(aupdate);
151 pa_aupdate_write_end(aupdate);
158 void pa_memtrap_remove(pa_memtrap *m) {
166 mx = pa_static_mutex_get(&mutex, FALSE, TRUE);
169 j = pa_aupdate_write_begin(aupdate);
170 memtrap_unlink(m, j);
171 j = pa_aupdate_write_swap(aupdate);
172 memtrap_unlink(m, j);
173 pa_aupdate_write_end(aupdate);
180 pa_memtrap *pa_memtrap_update(pa_memtrap *m, const void *start, size_t size) {
189 start = PA_PAGE_ALIGN_PTR(start);
190 size = PA_PAGE_ALIGN(size);
194 mx = pa_static_mutex_get(&mutex, FALSE, TRUE);
197 j = pa_aupdate_write_begin(aupdate);
199 if (m->start == start && m->size == size)
202 memtrap_unlink(m, j);
203 j = pa_aupdate_write_swap(aupdate);
205 m->start = (void*) start;
207 pa_atomic_store(&m->bad, 0);
209 j = pa_aupdate_write_swap(aupdate);
213 pa_aupdate_write_end(aupdate);
220 void pa_memtrap_install(void) {
225 memset(&sa, 0, sizeof(sa));
226 sa.sa_sigaction = signal_handler;
227 sa.sa_flags = SA_RESTART|SA_SIGINFO;
229 pa_assert_se(sigaction(SIGBUS, &sa, NULL) == 0);