RFSharedMem Class Reference

Inheritance diagram for RFSharedMem:

Public Member Functions
	RFSharedMem (const char *name)
RfShm_Cell &	GetCell (int id)
void *	ptr (void)
int	shmid (void)
bool	IsCreated (void)
void	lock (void)
void	unlock (void)
bool	isLocked (void)

Static Public Member Functions
static std::string	getTmpFileName (std::string user, std::string name)
static bool	getIdFromTmpFileName (std::string filename, int &shmid, int &semid)

Private Attributes
bool	m_new {false}
	True if we created the ring buffer ourselves (and need to clean it).
key_t	m_shmkey
	SHM key, see shmget(2).
key_t	m_semkey
	Semaphore key.
int	m_shmid {-1}
	shared memory id
int	m_semid {-1}
	semaphore id
void *	m_shmadr {nullptr}

Detailed Description

Definition at line 51 of file RFSharedMem.h.

Constructor & Destructor Documentation

RFSharedMem()

RFSharedMem

(

const char *

name

)

Definition at line 16 of file RFSharedMem.cc.

                                         : SharedMem(name, sizeof(RfShm_Data))
{
  RfShm_Data* rfshm = (RfShm_Data*) ptr();
  if (SharedMem::IsCreated()) {
    bzero((char*)rfshm, sizeof(RfShm_Data));
    for (int i = 0; i < RFSHM_MAX_PROCESS; i++) {
      (rfshm->cell[i]).pid = 0;
      (rfshm->cell[i]).type = 0;
      (rfshm->cell[i]).command = -1;
    }
  }
}

~RFSharedMem()

~RFSharedMem

(

)

Definition at line 29 of file RFSharedMem.cc.

{
}

Member Function Documentation

GetCell()

RfShm_Cell & GetCell

(

int

id

)

Definition at line 33 of file RFSharedMem.cc.

{
  RfShm_Data* rfshm = (RfShm_Data*) ptr();
  return rfshm->cell[id];
}

getIdFromTmpFileName()

bool getIdFromTmpFileName ( std::string  filename, int &  shmid, int &  semid  )

staticinherited

Definition at line 177 of file SharedMem.cc.

{
  char shminfo[256];
  int fd = open(filename.c_str(), O_RDONLY);
  if (fd < 0) {
    printf("SharedMem: error to reopen tmp file %s\n", filename.c_str());
    return false;
  }
  shmid = -1;
  semid = -1;
  memset(shminfo, 0, sizeof(shminfo));
  int n = read(fd, shminfo, sizeof(shminfo));
  close(fd);
  sscanf(shminfo, "%d %d", &shmid, &semid);
  return (n >= 3 && shmid >= 0 && semid >= 0);
}

getTmpFileName()

std::string getTmpFileName ( std::string  user, std::string  name  )

staticinherited

Definition at line 172 of file SharedMem.cc.

{
  return string("/tmp/") + user + string("_SHM_") + name;
}

IsCreated()

bool IsCreated ( void  )

inherited

Definition at line 167 of file SharedMem.cc.

{
  return m_new;
}

isLocked()

bool isLocked ( void  )

inherited

Definition at line 228 of file SharedMem.cc.

{
  int ignored = 0;
  return (semctl(m_semid, 0, GETVAL, ignored) == 0); //0: locked, 1: unlocked
}

lock()

void lock ( void  )

inherited

Definition at line 194 of file SharedMem.cc.

{
  struct sembuf sb;
  sb.sem_num = 0;
  sb.sem_op = -1;
  sb.sem_flg = 0;
  while (semop(m_semid, &sb, 1) == -1) {
    if (errno == EINTR) {
      //interrupted by signal (e.g. window size changed), try again
      continue;
    } else {
      perror("lock:semop");
      exit(-1);
    }
  }
}

ptr()

void * ptr ( void  )

inherited

Definition at line 157 of file SharedMem.cc.

{
  return (void*) m_shmadr;
}

shmid()

int shmid ( void  )

inherited

Definition at line 162 of file SharedMem.cc.

{
  return m_shmid;
}

unlock()

void unlock ( void  )

inherited

Definition at line 211 of file SharedMem.cc.

{
  struct sembuf sb;
  sb.sem_num = 0;
  sb.sem_op = 1;
  sb.sem_flg = 0;
  while (semop(m_semid, &sb, 1) == -1) {
    if (errno == EINTR) {
      //interrupted by signal (e.g. window size changed), try again
      continue;
    } else {
      perror("unlock:semop");
      exit(-1);
    }
  }
}

Member Data Documentation

m_new

bool m_new {false}

privateinherited

True if we created the ring buffer ourselves (and need to clean it).

Definition at line 38 of file SharedMem.h.

m_semid

int m_semid {-1}

privateinherited

semaphore id

Definition at line 43 of file SharedMem.h.

m_semkey

key_t m_semkey

privateinherited

Semaphore key.

Definition at line 40 of file SharedMem.h.

m_shmadr

void* m_shmadr {nullptr}

privateinherited

Definition at line 44 of file SharedMem.h.

m_shmid

int m_shmid {-1}

privateinherited

shared memory id

Definition at line 42 of file SharedMem.h.

m_shmkey

key_t m_shmkey

privateinherited

SHM key, see shmget(2).

Definition at line 39 of file SharedMem.h.

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The documentation for this class was generated from the following files:

• daq/rfarm/manager/include/RFSharedMem.h
• daq/rfarm/manager/src/RFSharedMem.cc