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/* -*- c++ -*- */
/*
* Copyright 2003,2011,2013 Free Software Foundation, Inc.
*
* This file is part of GNU Radio
*
* SPDX-License-Identifier: GPL-3.0-or-later
*
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "vmcircbuf_mmap_shm_open.h"
#include <assert.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdexcept>
#ifdef HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif
#ifdef HAVE_SYS_MMAN_H
#include <sys/mman.h>
#endif
#include "pagesize.h"
#include <gnuradio/sys_paths.h>
#include <errno.h>
#include <stdio.h>
#include <boost/format.hpp>
namespace gr {
vmcircbuf_mmap_shm_open::vmcircbuf_mmap_shm_open(int size) : gr::vmcircbuf(size)
{
#if !defined(HAVE_MMAP) || !defined(HAVE_SHM_OPEN)
std::stringstream error_msg;
error_msg << "mmap or shm_open is not available";
GR_LOG_ERROR(d_logger, error_msg.str());
throw std::runtime_error("gr::vmcircbuf_mmap_shm_open");
#else
gr::thread::scoped_lock guard(s_vm_mutex);
static int s_seg_counter = 0;
if (size <= 0 || (size % gr::pagesize()) != 0) {
GR_LOG_ERROR(d_logger, "invalid size =" + std::to_string(size));
throw std::runtime_error("gr::vmcircbuf_mmap_shm_open");
}
int shm_fd = -1;
std::string seg_name;
static bool portable_format = true;
// open a new named shared memory segment
while (1) {
if (portable_format) {
// This is the POSIX recommended "portable format".
// Of course the "portable format" doesn't work on some systems...
seg_name = str(boost::format("/gnuradio-%d-%d") % getpid() % s_seg_counter);
} else {
// Where the "portable format" doesn't work, we try building
// a full filesystem pathname pointing into a suitable temporary directory.
seg_name = str(boost::format("%s/gnuradio-%d-%d") % gr::tmp_path() %
getpid() % s_seg_counter);
}
shm_fd = shm_open(seg_name.c_str(), O_RDWR | O_CREAT | O_EXCL, 0600);
if (shm_fd == -1 && errno == EACCES && portable_format) {
portable_format = false;
continue; // try again using "non-portable format"
}
s_seg_counter++;
if (shm_fd == -1) {
if (errno ==
EEXIST) // Named segment already exists (shouldn't happen). Try again
continue;
static std::string msg =
str(boost::format("shm_open [%s] failed") % seg_name);
GR_LOG_ERROR(d_logger, msg.c_str());
throw std::runtime_error("gr::vmcircbuf_mmap_shm_open");
}
break;
}
// We've got a new shared memory segment fd open.
// Now set it's length to 2x what we really want and mmap it in.
if (ftruncate(shm_fd, (off_t)2 * size) == -1) {
close(shm_fd); // cleanup
GR_LOG_ERROR(d_logger, "ftruncate failed");
throw std::runtime_error("gr::vmcircbuf_mmap_shm_open");
}
void* first_copy =
mmap(0, 2 * size, PROT_READ | PROT_WRITE, MAP_SHARED, shm_fd, (off_t)0);
if (first_copy == MAP_FAILED) {
close(shm_fd); // cleanup
GR_LOG_ERROR(d_logger, "mmap (1) failed");
throw std::runtime_error("gr::vmcircbuf_mmap_shm_open");
}
// unmap the 2nd half
if (munmap((char*)first_copy + size, size) == -1) {
close(shm_fd); // cleanup
GR_LOG_ERROR(d_logger, "munmap (1) failed");
throw std::runtime_error("gr::vmcircbuf_mmap_shm_open");
}
// map the first half into the now available hole where the
// second half used to be.
void* second_copy = mmap((char*)first_copy + size,
size,
PROT_READ | PROT_WRITE,
MAP_SHARED,
shm_fd,
(off_t)0);
if (second_copy == MAP_FAILED) {
close(shm_fd); // cleanup
GR_LOG_ERROR(d_logger, "mmap (2) failed");
throw std::runtime_error("gr::vmcircbuf_mmap_shm_open");
}
#if 0 // OS/X doesn't allow you to resize the segment
// cut the shared memory segment down to size
if(ftruncate(shm_fd, (off_t)size) == -1) {
close(shm_fd); // cleanup
perror("gr::vmcircbuf_mmap_shm_open: ftruncate (2)");
throw std::runtime_error("gr::vmcircbuf_mmap_shm_open");
}
#endif
close(shm_fd); // fd no longer needed. The mapping is retained.
if (shm_unlink(seg_name.c_str()) == -1) { // unlink the seg_name.
GR_LOG_ERROR(d_logger, "shm_unlink failed");
throw std::runtime_error("gr::vmcircbuf_mmap_shm_open");
}
// Now remember the important stuff
d_base = (char*)first_copy;
d_size = size;
#endif
}
vmcircbuf_mmap_shm_open::~vmcircbuf_mmap_shm_open()
{
#if defined(HAVE_MMAP)
gr::thread::scoped_lock guard(s_vm_mutex);
if (munmap(d_base, 2 * d_size) == -1) {
GR_LOG_ERROR(d_logger, "munmap (2) failed");
}
#endif
}
// ----------------------------------------------------------------
// The factory interface
// ----------------------------------------------------------------
gr::vmcircbuf_factory* vmcircbuf_mmap_shm_open_factory::s_the_factory = 0;
gr::vmcircbuf_factory* vmcircbuf_mmap_shm_open_factory::singleton()
{
if (s_the_factory)
return s_the_factory;
s_the_factory = new gr::vmcircbuf_mmap_shm_open_factory();
return s_the_factory;
}
int vmcircbuf_mmap_shm_open_factory::granularity() { return gr::pagesize(); }
gr::vmcircbuf* vmcircbuf_mmap_shm_open_factory::make(int size)
{
try {
return new vmcircbuf_mmap_shm_open(size);
} catch (...) {
return 0;
}
}
} /* namespace gr */
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