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//////////////////////////////////////////////////////////////////////////////
//
// (C) Copyright Ion Gaztanaga 2005-2012. Distributed under the Boost
// Software License, Version 1.0. (See accompanying file
// LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//
// See http://www.boost.org/libs/interprocess for documentation.
//
//////////////////////////////////////////////////////////////////////////////
#ifndef BOOST_INTERPROCESS_POSIX_SEMAPHORE_WRAPPER_HPP
#define BOOST_INTERPROCESS_POSIX_SEMAPHORE_WRAPPER_HPP
#if defined(_MSC_VER)
# pragma once
#endif
#include <boost/interprocess/detail/posix_time_types_wrk.hpp>
#include <boost/interprocess/exceptions.hpp>
#include <boost/interprocess/creation_tags.hpp>
#include <boost/interprocess/detail/os_file_functions.hpp>
#include <boost/interprocess/detail/shared_dir_helpers.hpp>
#include <boost/interprocess/permissions.hpp>
#include <fcntl.h> //O_CREAT, O_*...
#include <unistd.h> //close
#include <string> //std::string
#include <semaphore.h> //sem_* family, SEM_VALUE_MAX
#include <sys/stat.h> //mode_t, S_IRWXG, S_IRWXO, S_IRWXU,
#include <boost/assert.hpp>
#ifdef SEM_FAILED
#define BOOST_INTERPROCESS_POSIX_SEM_FAILED (reinterpret_cast<sem_t*>(SEM_FAILED))
#else
#define BOOST_INTERPROCESS_POSIX_SEM_FAILED (reinterpret_cast<sem_t*>(-1))
#endif
#ifdef BOOST_INTERPROCESS_POSIX_TIMEOUTS
#include <boost/interprocess/sync/posix/ptime_to_timespec.hpp>
#else
#include <boost/interprocess/detail/os_thread_functions.hpp>
#include <boost/interprocess/sync/detail/locks.hpp>
#include <boost/interprocess/sync/detail/common_algorithms.hpp>
#endif
namespace boost {
namespace interprocess {
namespace ipcdetail {
inline bool semaphore_open
(sem_t *&handle, create_enum_t type, const char *origname,
unsigned int count = 0, const permissions &perm = permissions())
{
std::string name;
#ifndef BOOST_INTERPROCESS_FILESYSTEM_BASED_POSIX_SEMAPHORES
add_leading_slash(origname, name);
#else
create_shared_dir_cleaning_old_and_get_filepath(origname, name);
#endif
//Create new mapping
int oflag = 0;
switch(type){
case DoOpen:
{
//No addition
handle = ::sem_open(name.c_str(), oflag);
}
break;
case DoOpenOrCreate:
case DoCreate:
{
while(1){
oflag = (O_CREAT | O_EXCL);
handle = ::sem_open(name.c_str(), oflag, perm.get_permissions(), count);
if(handle != BOOST_INTERPROCESS_POSIX_SEM_FAILED){
//We can't change semaphore permissions!
//::fchmod(handle, perm.get_permissions());
break;
}
else if(errno == EEXIST && type == DoOpenOrCreate){
oflag = 0;
if( (handle = ::sem_open(name.c_str(), oflag)) != BOOST_INTERPROCESS_POSIX_SEM_FAILED
|| (errno != ENOENT) ){
break;
}
}
else{
break;
}
}
}
break;
default:
{
error_info err(other_error);
throw interprocess_exception(err);
}
}
//Check for error
if(handle == BOOST_INTERPROCESS_POSIX_SEM_FAILED){
throw interprocess_exception(error_info(errno));
}
return true;
}
inline void semaphore_close(sem_t *handle)
{
int ret = sem_close(handle);
if(ret != 0){
BOOST_ASSERT(0);
}
}
inline bool semaphore_unlink(const char *semname)
{
try{
std::string sem_str;
#ifndef BOOST_INTERPROCESS_FILESYSTEM_BASED_POSIX_SEMAPHORES
add_leading_slash(semname, sem_str);
#else
shared_filepath(semname, sem_str);
#endif
return 0 == sem_unlink(sem_str.c_str());
}
catch(...){
return false;
}
}
inline void semaphore_init(sem_t *handle, unsigned int initialCount)
{
int ret = sem_init(handle, 1, initialCount);
//According to SUSV3 version 2003 edition, the return value of a successful
//sem_init call is not defined, but -1 is returned on failure.
//In the future, a successful call might be required to return 0.
if(ret == -1){
error_info err = system_error_code();
throw interprocess_exception(err);
}
}
inline void semaphore_destroy(sem_t *handle)
{
int ret = sem_destroy(handle);
if(ret != 0){
BOOST_ASSERT(0);
}
}
inline void semaphore_post(sem_t *handle)
{
int ret = sem_post(handle);
if(ret != 0){
error_info err = system_error_code();
throw interprocess_exception(err);
}
}
inline void semaphore_wait(sem_t *handle)
{
int ret = sem_wait(handle);
if(ret != 0){
error_info err = system_error_code();
throw interprocess_exception(err);
}
}
inline bool semaphore_try_wait(sem_t *handle)
{
int res = sem_trywait(handle);
if(res == 0)
return true;
if(system_error_code() == EAGAIN){
return false;
}
error_info err = system_error_code();
throw interprocess_exception(err);
}
#ifndef BOOST_INTERPROCESS_POSIX_TIMEOUTS
struct semaphore_wrapper_try_wrapper
{
explicit semaphore_wrapper_try_wrapper(sem_t *handle)
: m_handle(handle)
{}
void wait()
{ semaphore_wait(m_handle); }
bool try_wait()
{ return semaphore_try_wait(m_handle); }
private:
sem_t *m_handle;
};
#endif
inline bool semaphore_timed_wait(sem_t *handle, const boost::posix_time::ptime &abs_time)
{
#ifdef BOOST_INTERPROCESS_POSIX_TIMEOUTS
//Posix does not support infinity absolute time so handle it here
if(abs_time == boost::posix_time::pos_infin){
semaphore_wait(handle);
return true;
}
timespec tspec = ptime_to_timespec(abs_time);
for (;;){
int res = sem_timedwait(handle, &tspec);
if(res == 0)
return true;
if (res > 0){
//buggy glibc, copy the returned error code to errno
errno = res;
}
if(system_error_code() == ETIMEDOUT){
return false;
}
error_info err = system_error_code();
throw interprocess_exception(err);
}
return false;
#else //#ifdef BOOST_INTERPROCESS_POSIX_TIMEOUTS
semaphore_wrapper_try_wrapper swtw(handle);
ipcdetail::lock_to_wait<semaphore_wrapper_try_wrapper> lw(swtw);
return ipcdetail::try_based_timed_lock(lw, abs_time);
#endif //#ifdef BOOST_INTERPROCESS_POSIX_TIMEOUTS
}
} //namespace ipcdetail {
} //namespace interprocess {
} //namespace boost {
#endif //#ifndef BOOST_INTERPROCESS_POSIX_SEMAPHORE_WRAPPER_HPP
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