none/tests/sem.c

   1 #define _GNU_SOURCE
   2
   3 #include <config.h>
   4 #include <errno.h>
   5 #include <stdio.h>
   6 #include <stdlib.h>
   7 #include <sys/types.h>
   8 #include <sys/ipc.h>
   9 #include <sys/sem.h>
  10 #include <time.h>
  11 #include <unistd.h>
  12
  13 void semctl_test (int trace, const char *fname)
  14 {
  15   key_t key;
  16   int semid;
  17   int nr_of_readers;
  18   int ret;
  19
  20   union semun {
  21      int              val;    /* Value for SETVAL */
  22      struct semid_ds *buf;    /* Buffer for IPC_STAT, IPC_SET */
  23      unsigned short  *array;  /* Array for GETALL, SETALL */
  24      struct seminfo  *__buf;  /* Buffer for IPC_INFO
  25                                  (Linux-specific) */
  26   } u;
  27
  28   struct semid_ds ds;
  29
  30   key = ftok (fname, 1);
  31   if (key == -1)
  32     perror ("ftok");
  33   nr_of_readers = 4;
  34
  35   semid = semget (key, 2 * nr_of_readers, IPC_CREAT + 0660);
  36   if (semid == -1) {
  37     perror ("semget");
  38   }
  39   if (trace)
  40      printf("semid %d\n", semid);
  41
  42   u.buf = &ds;
  43   ret = semctl (semid, 0, IPC_STAT, u);
  44   if (ret == -1)
  45      perror("semctl IPC_STAT");
  46   if (trace)
  47      printf("semid %d sem_nsems %d\n", semid, (int) ds.sem_nsems);
  48
  49   {
  50     unsigned short semarray[2 * nr_of_readers];
  51     for (int count = 0; count < nr_of_readers; count++) {
  52         semarray[2 * count] = 0;
  53         semarray[2 * count + 1] = 1000;
  54       }
  55     ret = semctl (semid, 0, SETALL, semarray);
  56     if (ret == -1)
  57       perror ("semctl SETALL");
  58   }
  59
  60   ret = semctl (semid, 0, IPC_RMID);
  61   if (ret == -1)
  62     perror ("semctl IPC_RMID");
  63 }
  64
  65 int main(int argc, char **argv)
  66 {
  67    int semid;
  68    struct sembuf sop;
  69 #ifdef HAVE_SEMTIMEDOP
  70    struct timespec ts;
  71 #endif
  72
  73    if ((semid = semget(IPC_PRIVATE, 1, 0600)) < 0)
  74    {
  75       perror("semget");
  76       exit(1);
  77    }
  78
  79    sop.sem_num = 0;
  80    sop.sem_op = 1;
  81    sop.sem_flg = 0;
  82
  83    if (semop(semid, &sop, 1) < 0)
  84    {
  85       perror("semop");
  86       semctl(semid, 0, IPC_RMID);
  87       exit(1);
  88    }
  89
  90    if (semctl(semid, 0, GETVAL) != 1)
  91    {
  92       perror("semctl GETVAL");
  93       semctl(semid, 0, IPC_RMID);
  94       exit(1);
  95    }
  96
  97    if (semctl(semid, 0, GETPID) != getpid())
  98    {
  99       perror("semctl GETPID");
 100       semctl(semid, 0, IPC_RMID);
 101       exit(1);
 102    }
 103
 104    /* The next call to semtimedop causes the program to hang on
 105       ppc32-linux (Yellow Dog 4.0).  I don't know why.  Hence the
 106       extended ifdef. */
 107 #if defined(HAVE_SEMTIMEDOP) && !defined(__powerpc__)
 108    sop.sem_num = 0;
 109    sop.sem_op = 0;
 110    sop.sem_flg = 0;
 111
 112    ts.tv_sec = 0;
 113    ts.tv_nsec = 1000000;
 114
 115    if (semtimedop(semid, &sop, 1, &ts) < 0 && errno != EAGAIN)
 116    {
 117       perror("semtimedop");
 118       semctl(semid, 0, IPC_RMID);
 119       exit(1);
 120    }
 121 #endif
 122
 123    sop.sem_num = 0;
 124    sop.sem_op = -1;
 125    sop.sem_flg = 0;
 126
 127    if (semop(semid, &sop, 1) < 0)
 128    {
 129       perror("semop");
 130       semctl(semid, 0, IPC_RMID);
 131       exit(1);
 132    }
 133
 134 #ifdef HAVE_SEMTIMEDOP
 135    sop.sem_num = 0;
 136    sop.sem_op = 0;
 137    sop.sem_flg = 0;
 138
 139    ts.tv_sec = 0;
 140    ts.tv_nsec = 1000;
 141
 142    if (semtimedop(semid, &sop, 1, &ts) < 0)
 143    {
 144       perror("semtimedop");
 145       semctl(semid, 0, IPC_RMID);
 146       exit(1);
 147    }
 148 #endif
 149
 150    if (semctl(semid, 0, IPC_RMID) < 0)
 151    {
 152       perror("semctl(IPC_RMID)");
 153       exit(1);
 154    }
 155
 156    semctl_test(argc > 1, argv[0]);
 157    exit(0);
 158 }