--- /dev/null
+/***
+ This file is part of PulseAudio.
+
+ Copyright 2009 Lennart Poettering
+
+ PulseAudio is free software; you can redistribute it and/or modify
+ it under the terms of the GNU Lesser General Public License as
+ published by the Free Software Foundation; either version 2.1 of the
+ License, or (at your option) any later version.
+
+ PulseAudio is distributed in the hope that it will be useful, but
+ WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with PulseAudio; if not, write to the Free Software
+ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
+ USA.
+***/
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <signal.h>
+#include <sys/mman.h>
+
+#include <pulse/xmalloc.h>
+
+#include <pulsecore/semaphore.h>
+#include <pulsecore/macro.h>
+#include <pulsecore/mutex.h>
+#include <pulsecore/core-util.h>
+
+#include "memtrap.h"
+
+struct pa_memtrap {
+ void *start;
+ size_t size;
+ pa_atomic_t bad;
+ pa_memtrap *next[2], *prev[2];
+};
+
+static pa_memtrap *memtraps[2] = { NULL, NULL };
+static pa_atomic_t read_lock = PA_ATOMIC_INIT(0);
+static pa_static_semaphore semaphore = PA_STATIC_SEMAPHORE_INIT;
+static pa_static_mutex write_lock = PA_STATIC_MUTEX_INIT;
+
+#define MSB (1U << (sizeof(unsigned)*8U-1))
+#define WHICH(n) (!!((n) & MSB))
+#define COUNTER(n) ((n) & ~MSB)
+
+pa_bool_t pa_memtrap_is_good(pa_memtrap *m) {
+ pa_assert(m);
+
+ return !pa_atomic_load(&m->bad);
+}
+
+static void sigsafe_error(const char *s) {
+ write(STDERR_FILENO, s, strlen(s));
+}
+
+static void signal_handler(int sig, siginfo_t* si, void *data) {
+ unsigned n, j;
+ pa_memtrap *m;
+ void *r;
+
+ /* Increase the lock counter */
+ n = (unsigned) pa_atomic_inc(&read_lock);
+
+ /* The uppermost bit tells us which list to look at */
+ j = WHICH(n);
+
+ /* When n is 0 we have about 2^31 threads running that
+ * all got a sigbus at the same time, oh my! */
+ pa_assert(COUNTER(n)+1 > 0);
+
+ for (m = memtraps[j]; m; m = m->next[j])
+ if (si->si_addr >= m->start &&
+ (uint8_t*) si->si_addr < (uint8_t*) m->start + m->size)
+ break;
+
+ if (!m)
+ goto fail;
+
+ pa_atomic_store(&m->bad, 1);
+
+ /* Remap anonymous memory into the bad segment */
+ if ((r = mmap(m->start, m->size, PROT_READ|PROT_WRITE, MAP_ANONYMOUS|MAP_FIXED|MAP_PRIVATE, -1, 0)) == MAP_FAILED) {
+ sigsafe_error("mmap() failed.\n");
+ goto fail;
+ }
+
+ pa_assert(r == m->start);
+
+ pa_atomic_dec(&read_lock);
+
+ /* Post the semaphore */
+ pa_semaphore_post(pa_static_semaphore_get(&semaphore, 0));
+
+ return;
+
+fail:
+ pa_atomic_dec(&read_lock);
+ abort();
+}
+
+static void memtrap_swap(unsigned n) {
+
+ for (;;) {
+
+ /* If the read counter is > 0 wait; if it is 0 try to swap the lists */
+ if (COUNTER(n) > 0)
+ pa_semaphore_wait(pa_static_semaphore_get(&semaphore, 0));
+ else if (pa_atomic_cmpxchg(&read_lock, (int) n, (int) (n ^ MSB)))
+ break;
+
+ n = (unsigned) pa_atomic_load(&read_lock);
+ }
+}
+
+static void memtrap_link(pa_memtrap *m, unsigned j) {
+ pa_assert(m);
+
+ m->prev[j] = NULL;
+ m->next[j] = memtraps[j];
+ memtraps[j] = m;
+}
+
+static void memtrap_unlink(pa_memtrap *m, int j) {
+ pa_assert(m);
+
+ if (m->next[j])
+ m->next[j]->prev[j] = m->prev[j];
+
+ if (m->prev[j])
+ m->prev[j]->next[j] = m->next[j];
+ else
+ memtraps[j] = m->next[j];
+}
+
+pa_memtrap* pa_memtrap_add(const void *start, size_t size) {
+ pa_memtrap *m = NULL;
+ pa_mutex *lock;
+ unsigned n, j;
+
+ pa_assert(start);
+ pa_assert(size > 0);
+ pa_assert(PA_PAGE_ALIGN_PTR(start) == start);
+ pa_assert(PA_PAGE_ALIGN(size) == size);
+
+ lock = pa_static_mutex_get(&write_lock, FALSE, FALSE);
+ pa_mutex_lock(lock);
+
+ if (!memtraps[0]) {
+ struct sigaction sa;
+
+ /* Before we install the signal handler, make sure the
+ * semaphore is valid so that the initialization of the
+ * semaphore doesn't have to happen from the signal handler */
+ pa_static_semaphore_get(&semaphore, 0);
+
+ memset(&sa, 0, sizeof(sa));
+ sa.sa_sigaction = signal_handler;
+ sa.sa_flags = SA_RESTART|SA_SIGINFO;
+
+ pa_assert_se(sigaction(SIGBUS, &sa, NULL) == 0);
+ }
+
+ n = (unsigned) pa_atomic_load(&read_lock);
+ j = WHICH(n);
+
+ m = pa_xnew(pa_memtrap, 1);
+ m->start = (void*) start;
+ m->size = size;
+ pa_atomic_store(&m->bad, 0);
+
+ memtrap_link(m, !j);
+ memtrap_swap(n);
+ memtrap_link(m, j);
+
+ pa_mutex_unlock(lock);
+
+ return m;
+}
+
+void pa_memtrap_remove(pa_memtrap *m) {
+ unsigned n, j;
+ pa_mutex *lock;
+
+ pa_assert(m);
+
+ lock = pa_static_mutex_get(&write_lock, FALSE, FALSE);
+ pa_mutex_lock(lock);
+
+ n = (unsigned) pa_atomic_load(&read_lock);
+ j = WHICH(n);
+
+ memtrap_unlink(m, !j);
+ memtrap_swap(n);
+ memtrap_unlink(m, j);
+
+ pa_xfree(m);
+
+ if (!memtraps[0]) {
+ struct sigaction sa;
+
+ memset(&sa, 0, sizeof(sa));
+ sa.sa_handler = SIG_DFL;
+ pa_assert_se(sigaction(SIGBUS, &sa, NULL) == 0);
+ }
+
+ pa_mutex_unlock(lock);
+}
+
+pa_memtrap *pa_memtrap_update(pa_memtrap *m, const void *start, size_t size) {
+ unsigned n, j;
+ pa_mutex *lock;
+
+ pa_assert(m);
+
+ pa_assert(start);
+ pa_assert(size > 0);
+ pa_assert(PA_PAGE_ALIGN_PTR(start) == start);
+ pa_assert(PA_PAGE_ALIGN(size) == size);
+
+ lock = pa_static_mutex_get(&write_lock, FALSE, FALSE);
+ pa_mutex_lock(lock);
+
+ if (m->start == start && m->size == size)
+ goto unlock;
+
+ n = (unsigned) pa_atomic_load(&read_lock);
+ j = WHICH(n);
+
+ memtrap_unlink(m, !j);
+ memtrap_swap(n);
+ memtrap_unlink(m, j);
+
+ m->start = (void*) start;
+ m->size = size;
+ pa_atomic_store(&m->bad, 0);
+
+ n = (unsigned) pa_atomic_load(&read_lock);
+ j = WHICH(n);
+
+ memtrap_link(m, !j);
+ memtrap_swap(n);
+ memtrap_link(m, j);
+
+unlock:
+ pa_mutex_unlock(lock);
+
+ return m;
+}
--- /dev/null
+#ifndef foopulsecorememtraphfoo
+#define foopulsecorememtraphfoo
+
+/***
+ This file is part of PulseAudio.
+
+ Copyright 2009 Lennart Poettering
+
+ PulseAudio is free software; you can redistribute it and/or modify
+ it under the terms of the GNU Lesser General Public License as
+ published by the Free Software Foundation; either version 2.1 of the
+ License, or (at your option) any later version.
+
+ PulseAudio is distributed in the hope that it will be useful, but
+ WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with PulseAudio; if not, write to the Free Software
+ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
+ USA.
+***/
+
+#include <sys/types.h>
+
+#include <pulsecore/macro.h>
+
+typedef struct pa_memtrap pa_memtrap;
+
+pa_memtrap* pa_memtrap_add(const void *start, size_t size);
+pa_memtrap *pa_memtrap_update(pa_memtrap *m, const void *start, size_t size);
+
+void pa_memtrap_remove(pa_memtrap *m);
+
+pa_bool_t pa_memtrap_is_good(pa_memtrap *m);
+
+#endif
--- /dev/null
+/***
+ This file is part of PulseAudio.
+
+ Copyright 2009 Lennart Poettering
+
+ PulseAudio is free software; you can redistribute it and/or modify
+ it under the terms of the GNU Lesser General Public License as
+ published by the Free Software Foundation; either version 2.1 of the
+ License, or (at your option) any later version.
+
+ PulseAudio is distributed in the hope that it will be useful, but
+ WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with PulseAudio; if not, write to the Free Software
+ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
+ USA.
+***/
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <fcntl.h>
+#include <sys/mman.h>
+
+#include <pulsecore/memtrap.h>
+#include <pulsecore/core-util.h>
+
+int main(int argc, char *argv[]) {
+ void *p;
+ int fd;
+ pa_memtrap *m;
+
+ pa_log_set_level(PA_LOG_DEBUG);
+
+ /* Create the memory map */
+ pa_assert_se((fd = open("sigbus-test-map", O_RDWR|O_TRUNC|O_CREAT, 0660)) >= 0);
+ pa_assert_se(unlink("sigbus-test-map") == 0);
+ pa_assert_se(ftruncate(fd, PA_PAGE_SIZE) >= 0);
+ pa_assert_se((p = mmap(NULL, PA_PAGE_SIZE, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0)) != MAP_FAILED);
+
+ /* Register memory map */
+ m = pa_memtrap_add(p, PA_PAGE_SIZE);
+
+ /* Use memory map */
+ pa_snprintf(p, PA_PAGE_SIZE, "This is a test that should work fine.");
+
+ /* Verify memory map */
+ pa_log("Let's see if this worked: %s", (char*) p);
+ pa_log("And memtrap says it is good: %s", pa_yes_no(pa_memtrap_is_good(m)));
+
+ /* Invalidate mapping */
+ pa_assert_se(ftruncate(fd, 0) >= 0);
+
+ /* Use memory map */
+ pa_snprintf(p, PA_PAGE_SIZE, "This is a test that should fail but get caught.");
+
+ /* Verify memory map */
+ pa_log("Let's see if this worked: %s", (char*) p);
+ pa_log("And memtrap says it is good: %s", pa_yes_no(pa_memtrap_is_good(m)));
+
+ pa_memtrap_remove(m);
+ munmap(p, PA_PAGE_SIZE);
+
+ return 0;
+}
projects / profile / ivi / pulseaudio-panda.git / commitdiff