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, see <http://www.gnu.org/licenses/>.
26 #ifdef HAVE_SYS_MMAN_H
30 /* This is deprecated on glibc but is still used by FreeBSD */
31 #if !defined(MAP_ANONYMOUS) && defined(MAP_ANON)
32 # define MAP_ANONYMOUS MAP_ANON
35 #include <pulse/xmalloc.h>
37 #include <pulsecore/core-util.h>
38 #include <pulsecore/aupdate.h>
39 #include <pulsecore/atomic.h>
40 #include <pulsecore/once.h>
41 #include <pulsecore/mutex.h>
49 pa_memtrap *next[2], *prev[2];
52 static pa_memtrap *memtraps[2] = { NULL, NULL };
53 static pa_aupdate *aupdate;
54 static pa_static_mutex mutex = PA_STATIC_MUTEX_INIT; /* only required to serialize access to the write side */
56 static void allocate_aupdate(void) {
58 aupdate = pa_aupdate_new();
62 bool pa_memtrap_is_good(pa_memtrap *m) {
65 return !pa_atomic_load(&m->bad);
69 static void sigsafe_error(const char *s) {
70 size_t ret PA_GCC_UNUSED;
71 ret = write(STDERR_FILENO, s, strlen(s));
74 static void signal_handler(int sig, siginfo_t* si, void *data) {
79 j = pa_aupdate_read_begin(aupdate);
81 for (m = memtraps[j]; m; m = m->next[j])
82 if (si->si_addr >= m->start &&
83 (uint8_t*) si->si_addr < (uint8_t*) m->start + m->size)
89 pa_atomic_store(&m->bad, 1);
91 /* Remap anonymous memory into the bad segment */
92 if ((r = mmap(m->start, m->size, PROT_READ|PROT_WRITE, MAP_ANONYMOUS|MAP_FIXED|MAP_PRIVATE, -1, 0)) == MAP_FAILED) {
93 sigsafe_error("mmap() failed.\n");
97 pa_assert(r == m->start);
99 pa_aupdate_read_end(aupdate);
103 pa_aupdate_read_end(aupdate);
105 sigsafe_error("Failed to handle SIGBUS.\n");
110 static void memtrap_link(pa_memtrap *m, unsigned j) {
115 if ((m->next[j] = memtraps[j]))
116 m->next[j]->prev[j] = m;
121 static void memtrap_unlink(pa_memtrap *m, unsigned j) {
125 m->next[j]->prev[j] = m->prev[j];
128 m->prev[j]->next[j] = m->next[j];
130 memtraps[j] = m->next[j];
133 pa_memtrap* pa_memtrap_add(const void *start, size_t size) {
134 pa_memtrap *m = NULL;
141 start = PA_PAGE_ALIGN_PTR(start);
142 size = PA_PAGE_ALIGN(size);
144 m = pa_xnew(pa_memtrap, 1);
145 m->start = (void*) start;
147 pa_atomic_store(&m->bad, 0);
151 mx = pa_static_mutex_get(&mutex, false, true);
154 j = pa_aupdate_write_begin(aupdate);
156 j = pa_aupdate_write_swap(aupdate);
158 pa_aupdate_write_end(aupdate);
165 void pa_memtrap_remove(pa_memtrap *m) {
173 mx = pa_static_mutex_get(&mutex, false, true);
176 j = pa_aupdate_write_begin(aupdate);
177 memtrap_unlink(m, j);
178 j = pa_aupdate_write_swap(aupdate);
179 memtrap_unlink(m, j);
180 pa_aupdate_write_end(aupdate);
187 pa_memtrap *pa_memtrap_update(pa_memtrap *m, const void *start, size_t size) {
196 start = PA_PAGE_ALIGN_PTR(start);
197 size = PA_PAGE_ALIGN(size);
201 mx = pa_static_mutex_get(&mutex, false, true);
204 j = pa_aupdate_write_begin(aupdate);
206 if (m->start == start && m->size == size)
209 memtrap_unlink(m, j);
210 pa_aupdate_write_swap(aupdate);
212 m->start = (void*) start;
214 pa_atomic_store(&m->bad, 0);
216 pa_assert_se(pa_aupdate_write_swap(aupdate) == j);
220 pa_aupdate_write_end(aupdate);
227 void pa_memtrap_install(void) {
228 #ifdef HAVE_SIGACTION
233 memset(&sa, 0, sizeof(sa));
234 sa.sa_sigaction = signal_handler;
235 sa.sa_flags = SA_RESTART|SA_SIGINFO;
237 pa_assert_se(sigaction(SIGBUS, &sa, NULL) == 0);
238 #ifdef __FreeBSD_kernel__
239 pa_assert_se(sigaction(SIGSEGV, &sa, NULL) == 0);