From ff48681aaef919cd2c85e4572928e936397a615c Mon Sep 17 00:00:00 2001 From: Lennart Poettering Date: Fri, 18 Aug 2006 19:46:20 +0000 Subject: add abstracted shared memory API git-svn-id: file:///home/lennart/svn/public/pulseaudio/trunk@1265 fefdeb5f-60dc-0310-8127-8f9354f1896f --- src/pulsecore/shm.c | 224 ++++++++++++++++++++++++++++++++++++++++++++++++++++ src/pulsecore/shm.h | 42 ++++++++++ 2 files changed, 266 insertions(+) create mode 100644 src/pulsecore/shm.c create mode 100644 src/pulsecore/shm.h 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 +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include +#include + +#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 + +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 -- cgit