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