include/linux/sem.h

   1 #ifndef _LINUX_SEM_H
   2 #define _LINUX_SEM_H
   3
   4 #include <linux/ipc.h>
   5
   6 /* semop flags */
   7 #define SEM_UNDO        0x1000  /* undo the operation on exit */
   8
   9 /* semctl Command Definitions. */
  10 #define GETPID  11       /* get sempid */
  11 #define GETVAL  12       /* get semval */
  12 #define GETALL  13       /* get all semval's */
  13 #define GETNCNT 14       /* get semncnt */
  14 #define GETZCNT 15       /* get semzcnt */
  15 #define SETVAL  16       /* set semval */
  16 #define SETALL  17       /* set all semval's */
  17
  18 /* ipcs ctl cmds */
  19 #define SEM_STAT 18
  20 #define SEM_INFO 19
  21
  22 /* One semid data structure for each set of semaphores in the system. */
  23 struct semid_ds {
  24         struct ipc_perm sem_perm;               /* permissions .. see ipc.h */
  25         __kernel_time_t sem_otime;              /* last semop time */
  26         __kernel_time_t sem_ctime;              /* last change time */
  27         struct sem      *sem_base;              /* ptr to first semaphore in array */
  28         struct sem_queue *sem_pending;          /* pending operations to be processed */
  29         struct sem_queue **sem_pending_last;    /* last pending operation */
  30         struct sem_undo *undo;                  /* undo requests on this array */
  31         unsigned short  sem_nsems;              /* no. of semaphores in array */
  32 };
  33
  34 /* semop system calls takes an array of these. */
  35 struct sembuf {
  36         unsigned short  sem_num;        /* semaphore index in array */
  37         short           sem_op;         /* semaphore operation */
  38         short           sem_flg;        /* operation flags */
  39 };
  40
  41 /* arg for semctl system calls. */
  42 union semun {
  43         int val;                        /* value for SETVAL */
  44         struct semid_ds *buf;           /* buffer for IPC_STAT & IPC_SET */
  45         unsigned short *array;          /* array for GETALL & SETALL */
  46         struct seminfo *__buf;          /* buffer for IPC_INFO */
  47         void *__pad;
  48 };
  49
  50 struct  seminfo {
  51         int semmap;
  52         int semmni;
  53         int semmns;
  54         int semmnu;
  55         int semmsl;
  56         int semopm;
  57         int semume;
  58         int semusz;
  59         int semvmx;
  60         int semaem;
  61 };
  62
  63 #define SEMMNI  128             /* ?  max # of semaphore identifiers */
  64 #define SEMMSL  32              /* <= 512 max num of semaphores per id */
  65 #define SEMMNS  (SEMMNI*SEMMSL) /* ? max # of semaphores in system */
  66 #define SEMOPM  32              /* ~ 100 max num of ops per semop call */
  67 #define SEMVMX  32767           /* semaphore maximum value */
  68
  69 /* unused */
  70 #define SEMUME  SEMOPM          /* max num of undo entries per process */
  71 #define SEMMNU  SEMMNS          /* num of undo structures system wide */
  72 #define SEMAEM  (SEMVMX >> 1)   /* adjust on exit max value */
  73 #define SEMMAP  SEMMNS          /* # of entries in semaphore map */
  74 #define SEMUSZ  20              /* sizeof struct sem_undo */
  75
  76 #ifdef __KERNEL__
  77
  78 /* One semaphore structure for each semaphore in the system. */
  79 struct sem {
  80         int     semval;         /* current value */
  81         int     sempid;         /* pid of last operation */
  82 };
  83
  84 /* One queue for each semaphore set in the system. */
  85 struct sem_queue {
  86         struct sem_queue *      next;    /* next entry in the queue */
  87         struct sem_queue **     prev;    /* previous entry in the queue, *(q->prev) == q */
  88         struct wait_queue *     sleeper; /* sleeping process */
  89         struct sem_undo *       undo;    /* undo structure */
  90         int                     pid;     /* process id of requesting process */
  91         int                     status;  /* completion status of operation */
  92         struct semid_ds *       sma;     /* semaphore array for operations */
  93         struct sembuf *         sops;    /* array of pending operations */
  94         int                     nsops;   /* number of operations */
  95 };
  96
  97 /* Each task has a list of undo requests. They are executed automatically
  98  * when the process exits.
  99  */
 100 struct sem_undo {
 101         struct sem_undo *       proc_next;      /* next entry on this process */
 102         struct sem_undo *       id_next;        /* next entry on this semaphore set */
 103         int                     semid;          /* semaphore set identifier */
 104         short *                 semadj;         /* array of adjustments, one per semaphore */
 105 };
 106
 107 asmlinkage int sys_semget (key_t key, int nsems, int semflg);
 108 asmlinkage int sys_semop (int semid, struct sembuf *sops, unsigned nsops);
 109 asmlinkage int sys_semctl (int semid, int semnum, int cmd, union semun arg);
 110
 111 #endif /* __KERNEL__ */
 112
 113 #endif /* _LINUX_SEM_H */