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>
47 pa_memtrap *next[2], *prev[2];
50 static pa_memtrap *memtraps[2] = { NULL, NULL };
51 static pa_aupdate *aupdate;
53 static void allocate_aupdate(void) {
55 aupdate = pa_aupdate_new();
59 pa_bool_t pa_memtrap_is_good(pa_memtrap *m) {
62 return !pa_atomic_load(&m->bad);
65 static void sigsafe_error(const char *s) {
66 write(STDERR_FILENO, s, strlen(s));
69 static void signal_handler(int sig, siginfo_t* si, void *data) {
74 j = pa_aupdate_read_begin(aupdate);
76 for (m = memtraps[j]; m; m = m->next[j])
77 if (si->si_addr >= m->start &&
78 (uint8_t*) si->si_addr < (uint8_t*) m->start + m->size)
84 pa_atomic_store(&m->bad, 1);
86 /* Remap anonymous memory into the bad segment */
87 if ((r = mmap(m->start, m->size, PROT_READ|PROT_WRITE, MAP_ANONYMOUS|MAP_FIXED|MAP_PRIVATE, -1, 0)) == MAP_FAILED) {
88 sigsafe_error("mmap() failed.\n");
92 pa_assert(r == m->start);
94 pa_aupdate_read_end(aupdate);
98 pa_aupdate_read_end(aupdate);
100 sigsafe_error("Failed to handle SIGBUS.\n");
104 static void memtrap_link(pa_memtrap *m, unsigned j) {
108 m->next[j] = memtraps[j];
112 static void memtrap_unlink(pa_memtrap *m, unsigned j) {
116 m->next[j]->prev[j] = m->prev[j];
119 m->prev[j]->next[j] = m->next[j];
121 memtraps[j] = m->next[j];
124 pa_memtrap* pa_memtrap_add(const void *start, size_t size) {
125 pa_memtrap *m = NULL;
131 start = PA_PAGE_ALIGN_PTR(start);
132 size = PA_PAGE_ALIGN(size);
134 m = pa_xnew(pa_memtrap, 1);
135 m->start = (void*) start;
137 pa_atomic_store(&m->bad, 0);
141 j = pa_aupdate_write_begin(aupdate);
143 j = pa_aupdate_write_swap(aupdate);
145 pa_aupdate_write_end(aupdate);
150 void pa_memtrap_remove(pa_memtrap *m) {
157 j = pa_aupdate_write_begin(aupdate);
158 memtrap_unlink(m, j);
159 j = pa_aupdate_write_swap(aupdate);
160 memtrap_unlink(m, j);
161 pa_aupdate_write_end(aupdate);
166 pa_memtrap *pa_memtrap_update(pa_memtrap *m, const void *start, size_t size) {
174 start = PA_PAGE_ALIGN_PTR(start);
175 size = PA_PAGE_ALIGN(size);
179 j = pa_aupdate_write_begin(aupdate);
181 if (m->start == start && m->size == size)
184 memtrap_unlink(m, j);
185 j = pa_aupdate_write_swap(aupdate);
187 m->start = (void*) start;
189 pa_atomic_store(&m->bad, 0);
191 j = pa_aupdate_write_swap(aupdate);
195 pa_aupdate_write_end(aupdate);
200 void pa_memtrap_install(void) {
205 memset(&sa, 0, sizeof(sa));
206 sa.sa_sigaction = signal_handler;
207 sa.sa_flags = SA_RESTART|SA_SIGINFO;
209 pa_assert_se(sigaction(SIGBUS, &sa, NULL) == 0);