"Fossies" - the Fresh Open Source Software Archive

Member "bonnie++-1.04/semaphore.cpp" (1 Jan 2001, 2290 Bytes) of package /linux/privat/bonnie++_1.04.tgz:

    1 #include "port.h"
    2 #include "semaphore.h"
    3 #include <unistd.h>
    4 #include <stdlib.h>
    5 
    6 Semaphore::Semaphore(int semKey, int numSems, int val)
    7  : m_semid(0)
    8  , m_semflg(IPC_CREAT | 0666)
    9  , m_semopen(false)
   10  , m_semKey(semKey)
   11  , m_numSems(numSems)
   12 {
   13   m_arg.val = (0);
   14   if(val)
   15   {
   16     if(create(val))
   17       exit(1);
   18   }
   19 }
   20 
   21 int Semaphore::clear_sem()
   22 {
   23   int semid;
   24   // have num-sems set to 1 so that we remove regardless of how many
   25   // semaphores were present.
   26   if((semid = semget(m_semKey, 1, 0666)) == -1)
   27   {
   28     perror("Can't get semaphore ID");
   29     return 1;
   30   }
   31   if(semctl(semid, 0, IPC_RMID, m_arg) == -1)
   32   {
   33     perror("Can't get remove semaphore");
   34     return 1;
   35   }
   36   printf("Semaphore removed.\n");
   37   return 0;
   38 }
   39 
   40 int Semaphore::create(int count)
   41 {
   42   if((m_semid = semget(m_semKey, m_numSems, m_semflg)) == -1)
   43   {
   44     perror("Can't get semaphore");
   45     return 1;
   46   }
   47   m_arg.val = count;
   48   int i;
   49   for(i = 0; i < m_numSems; ++i)
   50   {
   51     if(semctl(m_semid, i, SETVAL, m_arg) == -1)
   52     {
   53       perror("Can't set semaphore value");
   54       return 1;
   55     }
   56   }
   57   m_semopen = true;
   58   return 0;
   59 }
   60 
   61 int Semaphore::get_semid()
   62 {
   63   int semflg = 0666;
   64   if ((m_semid = semget(m_semKey, m_numSems, semflg)) == -1)
   65   {
   66     perror("Can't get semaphore ID");
   67     return 1;
   68   }
   69   m_semopen = true;
   70   return 0;
   71 }
   72 
   73 int Semaphore::decrement_and_wait(int nr_sem)
   74 {
   75   if(!m_semopen)
   76     return 0;
   77   struct sembuf sops;
   78   sops.sem_num = nr_sem;
   79   sops.sem_op = -1;
   80   sops.sem_flg = IPC_NOWAIT;
   81   if(semop(m_semid, &sops, 1) == -1)
   82   {
   83     perror("semop: semop failed.\n");
   84     return 1;
   85   }
   86   sops.sem_num = nr_sem;
   87   sops.sem_op = 0;
   88   sops.sem_flg = SEM_UNDO;
   89   if(semop(m_semid, &sops, 1) == -1)
   90   {
   91     perror("semop: semop failed.\n");
   92     return 1;
   93   }
   94   return 0;
   95 }
   96 
   97 int Semaphore::get_mutex()
   98 {
   99   if(!m_semopen)
  100     return 0;
  101   struct sembuf sops;
  102   sops.sem_num = 0;
  103   sops.sem_op = -1;
  104   sops.sem_flg = SEM_UNDO;
  105   if(semop(m_semid, &sops, 1) == -1)
  106   {
  107     perror("semop: semop failed.\n");
  108     return 1;
  109   }
  110   return 0;
  111 }
  112 
  113 int Semaphore::put_mutex()
  114 {
  115   if(!m_semopen)
  116     return 0;
  117   struct sembuf sops;
  118   sops.sem_num = 0;
  119   sops.sem_op = 1;
  120   sops.sem_flg = IPC_NOWAIT;
  121   if(semop(m_semid, &sops, 1) == -1)
  122   {
  123     perror("semop: semop failed.\n");
  124     return 1;
  125   }
  126   return 0;
  127 }