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 /* Obsolete, used only for backwards compatibility and libc5 compiles */
  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 /* Include the definition of semid64_ds */
  35 #include <asm/sembuf.h>
  36
  37 /* semop system calls takes an array of these. */
  38 struct sembuf {
  39         unsigned short  sem_num;        /* semaphore index in array */
  40         short           sem_op;         /* semaphore operation */
  41         short           sem_flg;        /* operation flags */
  42 };
  43
  44 /* arg for semctl system calls. */
  45 union semun {
  46         int val;                        /* value for SETVAL */
  47         struct semid_ds *buf;           /* buffer for IPC_STAT & IPC_SET */
  48         unsigned short *array;          /* array for GETALL & SETALL */
  49         struct seminfo *__buf;          /* buffer for IPC_INFO */
  50         void *__pad;
  51 };
  52
  53 struct  seminfo {
  54         int semmap;
  55         int semmni;
  56         int semmns;
  57         int semmnu;
  58         int semmsl;
  59         int semopm;
  60         int semume;
  61         int semusz;
  62         int semvmx;
  63         int semaem;
  64 };
  65
  66 #define SEMMNI  128             /* <= IPCMNI  max # of semaphore identifiers */
  67 #define SEMMSL  250             /* <= 8 000 max num of semaphores per id */
  68 #define SEMMNS  (SEMMNI*SEMMSL) /* <= INT_MAX max # of semaphores in system */
  69 #define SEMOPM  32              /* <= 1 000 max num of ops per semop call */
  70 #define SEMVMX  32767           /* <= 32767 semaphore maximum value */
  71
  72 /* unused */
  73 #define SEMUME  SEMOPM          /* max num of undo entries per process */
  74 #define SEMMNU  SEMMNS          /* num of undo structures system wide */
  75 #define SEMAEM  (SEMVMX >> 1)   /* adjust on exit max value */
  76 #define SEMMAP  SEMMNS          /* # of entries in semaphore map */
  77 #define SEMUSZ  20              /* sizeof struct sem_undo */
  78
  79 #ifdef __KERNEL__
  80
  81 /* One semaphore structure for each semaphore in the system. */
  82 struct sem {
  83         int     semval;         /* current value */
  84         int     sempid;         /* pid of last operation */
  85 };
  86
  87 /* One sem_array data structure for each set of semaphores in the system. */
  88 struct sem_array {
  89         struct kern_ipc_perm    sem_perm;       /* permissions .. see ipc.h */
  90         time_t                  sem_otime;      /* last semop time */
  91         time_t                  sem_ctime;      /* last change time */
  92         struct sem              *sem_base;      /* ptr to first semaphore in array */
  93         struct sem_queue        *sem_pending;   /* pending operations to be processed */
  94         struct sem_queue        **sem_pending_last; /* last pending operation */
  95         struct sem_undo         *undo;          /* undo requests on this array */
  96         unsigned long           sem_nsems;      /* no. of semaphores in array */
  97 };
  98
  99 /* One queue for each sleeping process in the system. */
 100 struct sem_queue {
 101         struct sem_queue *      next;    /* next entry in the queue */
 102         struct sem_queue **     prev;    /* previous entry in the queue, *(q->prev) == q */
 103         struct task_struct*     sleeper; /* this process */
 104         struct sem_undo *       undo;    /* undo structure */
 105         int                     pid;     /* process id of requesting process */
 106         int                     status;  /* completion status of operation */
 107         struct sem_array *      sma;     /* semaphore array for operations */
 108         int                     id;      /* internal sem id */
 109         struct sembuf *         sops;    /* array of pending operations */
 110         int                     nsops;   /* number of operations */
 111         int                     alter;   /* operation will alter semaphore */
 112 };
 113
 114 /* Each task has a list of undo requests. They are executed automatically
 115  * when the process exits.
 116  */
 117 struct sem_undo {
 118         struct sem_undo *       proc_next;      /* next entry on this process */
 119         struct sem_undo *       id_next;        /* next entry on this semaphore set */
 120         int                     semid;          /* semaphore set identifier */
 121         short *                 semadj;         /* array of adjustments, one per semaphore */
 122 };
 123
 124 asmlinkage long sys_semget (key_t key, int nsems, int semflg);
 125 asmlinkage long sys_semop (int semid, struct sembuf *sops, unsigned nsops);
 126 asmlinkage long sys_semctl (int semid, int semnum, int cmd, union semun arg);
 127
 128 #endif /* __KERNEL__ */
 129
 130 #endif /* _LINUX_SEM_H */