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authorLennart Poettering <lennart@poettering.net>2006-08-18 19:46:20 +0000
committerLennart Poettering <lennart@poettering.net>2006-08-18 19:46:20 +0000
commitff48681aaef919cd2c85e4572928e936397a615c (patch)
tree9832398465d684268b5a01f3d2f4256be90633c7 /src/pulsecore
parent20d0823e35e62165cc4bf277020814521117a632 (diff)
add abstracted shared memory API
git-svn-id: file:///home/lennart/svn/public/pulseaudio/trunk@1265 fefdeb5f-60dc-0310-8127-8f9354f1896f
Diffstat (limited to 'src/pulsecore')
-rw-r--r--src/pulsecore/shm.c224
-rw-r--r--src/pulsecore/shm.h42
2 files changed, 266 insertions, 0 deletions
diff --git a/src/pulsecore/shm.c b/src/pulsecore/shm.c
new file mode 100644
index 00000000..ad9dc46a
--- /dev/null
+++ b/src/pulsecore/shm.c
@@ -0,0 +1,224 @@
+/* $Id$ */
+
+/***
+ This file is part of PulseAudio.
+
+ 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
+ Lesser 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 <assert.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/mman.h>
+#include <stdio.h>
+#include <errno.h>
+#include <string.h>
+#include <sys/stat.h>
+
+#include <pulsecore/core-error.h>
+#include <pulsecore/log.h>
+#include <pulsecore/random.h>
+
+#include "shm.h"
+
+#if defined(__linux__) && !defined(MADV_REMOVE)
+#define MADV_REMOVE 9
+#endif
+
+#define MAX_SHM_SIZE (1024*1024*20)
+
+static char *segment_name(char *fn, size_t l, unsigned id) {
+ snprintf(fn, l, "/pulse-shm-%u", id);
+ return fn;
+}
+
+int pa_shm_create_rw(pa_shm *m, size_t size, int shared, mode_t mode) {
+ char fn[32];
+ int fd = -1;
+
+ assert(m);
+ assert(size > 0);
+ assert(size < MAX_SHM_SIZE);
+ assert(mode >= 0600);
+
+ if (!shared) {
+ m->id = 0;
+ m->size = size;
+
+#ifdef MAP_ANONYMOUS
+ if ((m->ptr = mmap(NULL, m->size, PROT_READ|PROT_WRITE, MAP_ANONYMOUS, fd, 0)) == MAP_FAILED) {
+ pa_log(__FILE__": mmap() failed: %s", pa_cstrerror(errno));
+ goto fail;
+ }
+#else
+ m->ptr = pa_xmalloc(m->size);
+#endif
+
+ m->do_unlink = 0;
+
+ } else {
+ pa_random(&m->id, sizeof(m->id));
+ segment_name(fn, sizeof(fn), m->id);
+
+ if ((fd = shm_open(fn, O_RDWR|O_CREAT|O_EXCL, mode & 0444)) < 0) {
+ pa_log(__FILE__": shm_open() failed: %s", pa_cstrerror(errno));
+ goto fail;
+ }
+
+ if (ftruncate(fd, m->size = size) < 0) {
+ pa_log(__FILE__": ftruncate() failed: %s", pa_cstrerror(errno));
+ goto fail;
+ }
+
+ if ((m->ptr = mmap(NULL, m->size, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0)) == MAP_FAILED) {
+ pa_log(__FILE__": mmap() failed: %s", pa_cstrerror(errno));
+ goto fail;
+ }
+
+ close(fd);
+ m->do_unlink = 1;
+ }
+
+ m->shared = shared;
+
+ return 0;
+
+fail:
+
+ if (fd >= 0) {
+ shm_unlink(fn);
+ close(fd);
+ }
+
+ return -1;
+}
+
+void pa_shm_free(pa_shm *m) {
+ char fn[32];
+
+ assert(m);
+ assert(m->ptr && m->ptr != MAP_FAILED);
+ assert(m->size > 0);
+
+#ifndef MAP_ANONYMOUS
+ if (!m->shared)
+ pa_xfree(m->ptr);
+ else
+#endif
+
+ if (munmap(m->ptr, m->size) < 0)
+ pa_log(__FILE__": munmap() failed: %s", pa_cstrerror(errno));
+
+ if (m->do_unlink) {
+ segment_name(fn, sizeof(fn), m->id);
+
+ if (shm_unlink(fn) < 0)
+ pa_log(__FILE__":shm_unlink(%s) failed: %s", fn, pa_cstrerror(errno));
+ }
+
+ memset(m, 0, sizeof(*m));
+}
+
+void pa_shm_punch(pa_shm *m, size_t offset, size_t size) {
+ void *ptr;
+
+ assert(m);
+ assert(m->ptr && m->ptr != MAP_FAILED);
+ assert(m->size > 0);
+ assert(m->do_unlink);
+ assert(offset < m->size);
+ assert(offset+size < m->size);
+
+ /* You're welcome to implement this as NOOP on systems that don't
+ * support it */
+
+ ptr = (uint8_t*) m->ptr + offset;
+
+#ifdef __linux__
+{
+ /* On Linux ptr must be page aligned */
+ long psz = sysconf(_SC_PAGESIZE);
+ unsigned o;
+
+ o = ((unsigned long) ptr) - ((((unsigned long) ptr)/psz) * psz);
+
+ if (o > 0) {
+ ptr = (uint8_t*) ptr + (psz - o);
+ size -= psz - o;
+ }
+}
+#endif
+
+#ifdef MADV_REMOVE
+ if (madvise(ptr, size, MADV_REMOVE) >= 0)
+ return;
+#endif
+
+#ifdef MADV_FREE
+ if (madvise(ptr, size, MADV_FREE) >= 0)
+ return;
+#endif
+
+#ifdef MADV_DONTNEED
+ madvise(ptr, size, MADV_DONTNEED);
+#endif
+}
+
+int pa_shm_attach_ro(pa_shm *m, unsigned id) {
+ char fn[32];
+ int fd = -1;
+ struct stat st;
+
+ assert(m);
+
+ segment_name(fn, sizeof(fn), m->id = id);
+
+ if ((fd = shm_open(fn, O_RDONLY, 0)) < 0) {
+ pa_log(__FILE__": shm_open() failed: %s", pa_cstrerror(errno));
+ goto fail;
+ }
+
+ if (fstat(fd, &st) < 0) {
+ pa_log(__FILE__": fstat() failed: %s", pa_cstrerror(errno));
+ goto fail;
+ }
+
+ if (st.st_size <= 0 || st.st_size > MAX_SHM_SIZE) {
+ pa_log(__FILE__": Invalid shared memory segment size");
+ goto fail;
+ }
+
+ m->size = st.st_size;
+
+ if ((m->ptr = mmap(NULL, m->size, PROT_READ, MAP_SHARED, fd, 0)) == MAP_FAILED) {
+ pa_log(__FILE__": mmap() failed: %s", pa_cstrerror(errno));
+ goto fail;
+ }
+
+ m->do_unlink = 0;
+ m->shared = 1;
+
+ close(fd);
+
+ return 0;
+
+fail:
+ if (fd >= 0)
+ close(fd);
+
+ return -1;
+}
diff --git a/src/pulsecore/shm.h b/src/pulsecore/shm.h
new file mode 100644
index 00000000..ea72403a
--- /dev/null
+++ b/src/pulsecore/shm.h
@@ -0,0 +1,42 @@
+#ifndef foopulseshmhfoo
+#define foopulseshmhfoo
+
+/* $Id$ */
+
+/***
+ This file is part of PulseAudio.
+
+ 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
+ Lesser 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>
+
+typedef struct pa_shm {
+ unsigned id;
+ void *ptr;
+ size_t size;
+ int do_unlink;
+ int shared;
+} pa_shm;
+
+int pa_shm_create_rw(pa_shm *m, size_t size, int shared, mode_t mode);
+int pa_shm_attach_ro(pa_shm *m, unsigned id);
+
+void pa_shm_punch(pa_shm *m, size_t offset, size_t size);
+
+void pa_shm_free(pa_shm *m);
+
+#endif