Chris@16: //////////////////////////////////////////////////////////////////////////////
Chris@16: //
Chris@16: // (C) Copyright Ion Gaztanaga 2005-2012. Distributed under the Boost
Chris@16: // Software License, Version 1.0. (See accompanying file
Chris@16: // LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
Chris@16: //
Chris@16: // See http://www.boost.org/libs/interprocess for documentation.
Chris@16: //
Chris@16: //////////////////////////////////////////////////////////////////////////////
Chris@16: 
Chris@16: #ifndef BOOST_INTERPROCESS_POSIX_SEMAPHORE_WRAPPER_HPP
Chris@16: #define BOOST_INTERPROCESS_POSIX_SEMAPHORE_WRAPPER_HPP
Chris@16: 
Chris@16: #include <boost/interprocess/detail/posix_time_types_wrk.hpp>
Chris@16: #include <boost/interprocess/exceptions.hpp>
Chris@16: #include <boost/interprocess/creation_tags.hpp>
Chris@16: #include <boost/interprocess/detail/os_file_functions.hpp>
Chris@16: #include <boost/interprocess/detail/tmp_dir_helpers.hpp>
Chris@16: #include <boost/interprocess/permissions.hpp>
Chris@16: 
Chris@16: #include <fcntl.h>      //O_CREAT, O_*...
Chris@16: #include <unistd.h>     //close
Chris@16: #include <string>       //std::string
Chris@16: #include <semaphore.h>  //sem_* family, SEM_VALUE_MAX
Chris@16: #include <sys/stat.h>   //mode_t, S_IRWXG, S_IRWXO, S_IRWXU,
Chris@16: #include <boost/assert.hpp>
Chris@16: 
Chris@16: #ifdef SEM_FAILED
Chris@16: #define BOOST_INTERPROCESS_POSIX_SEM_FAILED (reinterpret_cast<sem_t*>(SEM_FAILED))
Chris@16: #else
Chris@16: #define BOOST_INTERPROCESS_POSIX_SEM_FAILED (reinterpret_cast<sem_t*>(-1))
Chris@16: #endif
Chris@16: 
Chris@16: #ifdef BOOST_INTERPROCESS_POSIX_TIMEOUTS
Chris@16: #include <boost/interprocess/sync/posix/ptime_to_timespec.hpp>
Chris@16: #else
Chris@16: #include <boost/interprocess/detail/os_thread_functions.hpp>
Chris@16: #include <boost/interprocess/sync/spin/wait.hpp>
Chris@16: #endif
Chris@16: 
Chris@16: namespace boost {
Chris@16: namespace interprocess {
Chris@16: namespace ipcdetail {
Chris@16: 
Chris@16: inline bool semaphore_open
Chris@16:    (sem_t *&handle, create_enum_t type, const char *origname,
Chris@16:     unsigned int count = 0, const permissions &perm = permissions())
Chris@16: {
Chris@16:    std::string name;
Chris@16:    #ifndef BOOST_INTERPROCESS_FILESYSTEM_BASED_POSIX_SEMAPHORES
Chris@16:    add_leading_slash(origname, name);
Chris@16:    #else
Chris@16:    create_tmp_and_clean_old_and_get_filename(origname, name);
Chris@16:    #endif
Chris@16: 
Chris@16:    //Create new mapping
Chris@16:    int oflag = 0;
Chris@16:    switch(type){
Chris@16:       case DoOpen:
Chris@16:       {
Chris@16:          //No addition
Chris@16:          handle = ::sem_open(name.c_str(), oflag);
Chris@16:       }
Chris@16:       break;
Chris@16:       case DoOpenOrCreate:
Chris@16:       case DoCreate:
Chris@16:       {
Chris@16:          while(1){
Chris@16:             oflag = (O_CREAT | O_EXCL);
Chris@16:             handle = ::sem_open(name.c_str(), oflag, perm.get_permissions(), count);
Chris@16:             if(handle != BOOST_INTERPROCESS_POSIX_SEM_FAILED){
Chris@16:                //We can't change semaphore permissions!
Chris@16:                //::fchmod(handle, perm.get_permissions());
Chris@16:                break;
Chris@16:             }
Chris@16:             else if(errno == EEXIST && type == DoOpenOrCreate){
Chris@16:                oflag = 0;
Chris@16:                if( (handle = ::sem_open(name.c_str(), oflag)) != BOOST_INTERPROCESS_POSIX_SEM_FAILED
Chris@16:                    || (errno != ENOENT) ){
Chris@16:                   break;
Chris@16:                }
Chris@16:             }
Chris@16:             else{
Chris@16:                break;
Chris@16:             }
Chris@16:          }
Chris@16:       }
Chris@16:       break;
Chris@16:       default:
Chris@16:       {
Chris@16:          error_info err(other_error);
Chris@16:          throw interprocess_exception(err);
Chris@16:       }
Chris@16:    }
Chris@16: 
Chris@16:    //Check for error
Chris@16:    if(handle == BOOST_INTERPROCESS_POSIX_SEM_FAILED){
Chris@16:       throw interprocess_exception(error_info(errno));
Chris@16:    }
Chris@16: 
Chris@16:    return true;
Chris@16: }
Chris@16: 
Chris@16: inline void semaphore_close(sem_t *handle)
Chris@16: {
Chris@16:    int ret = sem_close(handle);
Chris@16:    if(ret != 0){
Chris@16:       BOOST_ASSERT(0);
Chris@16:    }
Chris@16: }
Chris@16: 
Chris@16: inline bool semaphore_unlink(const char *semname)
Chris@16: {
Chris@16:    try{
Chris@16:       std::string sem_str;
Chris@16:       #ifndef BOOST_INTERPROCESS_FILESYSTEM_BASED_POSIX_SEMAPHORES
Chris@16:       add_leading_slash(semname, sem_str);
Chris@16:       #else
Chris@16:       tmp_filename(semname, sem_str);
Chris@16:       #endif
Chris@16:       return 0 == sem_unlink(sem_str.c_str());
Chris@16:    }
Chris@16:    catch(...){
Chris@16:       return false;
Chris@16:    }
Chris@16: }
Chris@16: 
Chris@16: inline void semaphore_init(sem_t *handle, unsigned int initialCount)
Chris@16: {
Chris@16:    int ret = sem_init(handle, 1, initialCount);
Chris@16:    //According to SUSV3 version 2003 edition, the return value of a successful
Chris@16:    //sem_init call is not defined, but -1 is returned on failure.
Chris@16:    //In the future, a successful call might be required to return 0.
Chris@16:    if(ret == -1){
Chris@16:       throw interprocess_exception(system_error_code());
Chris@16:    }
Chris@16: }
Chris@16: 
Chris@16: inline void semaphore_destroy(sem_t *handle)
Chris@16: {
Chris@16:    int ret = sem_destroy(handle);
Chris@16:    if(ret != 0){
Chris@16:       BOOST_ASSERT(0);
Chris@16:    }
Chris@16: }
Chris@16: 
Chris@16: inline void semaphore_post(sem_t *handle)
Chris@16: {
Chris@16:    int ret = sem_post(handle);
Chris@16:    if(ret != 0){
Chris@16:       throw interprocess_exception(system_error_code());
Chris@16:    }
Chris@16: }
Chris@16: 
Chris@16: inline void semaphore_wait(sem_t *handle)
Chris@16: {
Chris@16:    int ret = sem_wait(handle);
Chris@16:    if(ret != 0){
Chris@16:       throw interprocess_exception(system_error_code());
Chris@16:    }
Chris@16: }
Chris@16: 
Chris@16: inline bool semaphore_try_wait(sem_t *handle)
Chris@16: {
Chris@16:    int res = sem_trywait(handle);
Chris@16:    if(res == 0)
Chris@16:       return true;
Chris@16:    if(system_error_code() == EAGAIN){
Chris@16:       return false;
Chris@16:    }
Chris@16:    throw interprocess_exception(system_error_code());
Chris@16:    return false;
Chris@16: }
Chris@16: 
Chris@16: inline bool semaphore_timed_wait(sem_t *handle, const boost::posix_time::ptime &abs_time)
Chris@16: {
Chris@16:    if(abs_time == boost::posix_time::pos_infin){
Chris@16:       semaphore_wait(handle);
Chris@16:       return true;
Chris@16:    }
Chris@16:    #ifdef BOOST_INTERPROCESS_POSIX_TIMEOUTS
Chris@16:    timespec tspec = ptime_to_timespec(abs_time);
Chris@16:    for (;;){
Chris@16:       int res = sem_timedwait(handle, &tspec);
Chris@16:       if(res == 0)
Chris@16:          return true;
Chris@16:       if (res > 0){
Chris@16:          //buggy glibc, copy the returned error code to errno
Chris@16:          errno = res;
Chris@16:       }
Chris@16:       if(system_error_code() == ETIMEDOUT){
Chris@16:          return false;
Chris@16:       }
Chris@16:       throw interprocess_exception(system_error_code());
Chris@16:    }
Chris@16:    return false;
Chris@16:    #else //#ifdef BOOST_INTERPROCESS_POSIX_TIMEOUTS
Chris@16:    boost::posix_time::ptime now;
Chris@16:    spin_wait swait;
Chris@16:    do{
Chris@16:       if(semaphore_try_wait(handle))
Chris@16:          return true;
Chris@16:       swait.yield();
Chris@16:    }while((now = microsec_clock::universal_time()) < abs_time);
Chris@16:    return false;
Chris@16:    #endif   //#ifdef BOOST_INTERPROCESS_POSIX_TIMEOUTS
Chris@16: }
Chris@16: 
Chris@16: }  //namespace ipcdetail {
Chris@16: }  //namespace interprocess {
Chris@16: }  //namespace boost {
Chris@16: 
Chris@16: #endif   //#ifndef BOOST_INTERPROCESS_POSIX_SEMAPHORE_WRAPPER_HPP