include/linux/sem.h

   1 #ifndef _LINUX_SEM_H
   2 #define _LINUX_SEM_H
   3
   4 #include <linux/ipc.h>
   5 #include <asm/atomic.h>
   6
   7 /* semop flags */
   8 #define SEM_UNDO        0x1000  /* undo the operation on exit */
   9
  10 /* semctl Command Definitions. */
  11 #define GETPID  11       /* get sempid */
  12 #define GETVAL  12       /* get semval */
  13 #define GETALL  13       /* get all semval's */
  14 #define GETNCNT 14       /* get semncnt */
  15 #define GETZCNT 15       /* get semzcnt */
  16 #define SETVAL  16       /* set semval */
  17 #define SETALL  17       /* set all semval's */
  18
  19 /* ipcs ctl cmds */
  20 #define SEM_STAT 18
  21 #define SEM_INFO 19
  22
  23 /* Obsolete, used only for backwards compatibility and libc5 compiles */
  24 struct semid_ds {
  25         struct ipc_perm sem_perm;               /* permissions .. see ipc.h */
  26         __kernel_time_t sem_otime;              /* last semop time */
  27         __kernel_time_t sem_ctime;              /* last change time */
  28         struct sem      *sem_base;              /* ptr to first semaphore in array */
  29         struct sem_queue *sem_pending;          /* pending operations to be processed */
  30         struct sem_queue **sem_pending_last;    /* last pending operation */
  31         struct sem_undo *undo;                  /* undo requests on this array */
  32         unsigned short  sem_nsems;              /* no. of semaphores in array */
  33 };
  34
  35 /* Include the definition of semid64_ds */
  36 #include <asm/sembuf.h>
  37
  38 /* semop system calls takes an array of these. */
  39 struct sembuf {
  40         unsigned short  sem_num;        /* semaphore index in array */
  41         short           sem_op;         /* semaphore operation */
  42         short           sem_flg;        /* operation flags */
  43 };
  44
  45 /* arg for semctl system calls. */
  46 union semun {
  47         int val;                        /* value for SETVAL */
  48         struct semid_ds __user *buf;    /* buffer for IPC_STAT & IPC_SET */
  49         unsigned short __user *array;   /* array for GETALL & SETALL */
  50         struct seminfo __user *__buf;   /* buffer for IPC_INFO */
  51         void __user *__pad;
  52 };
  53
  54 struct  seminfo {
  55         int semmap;
  56         int semmni;
  57         int semmns;
  58         int semmnu;
  59         int semmsl;
  60         int semopm;
  61         int semume;
  62         int semusz;
  63         int semvmx;
  64         int semaem;
  65 };
  66
  67 #define SEMMNI  128             /* <= IPCMNI  max # of semaphore identifiers */
  68 #define SEMMSL  250             /* <= 8 000 max num of semaphores per id */
  69 #define SEMMNS  (SEMMNI*SEMMSL) /* <= INT_MAX max # of semaphores in system */
  70 #define SEMOPM  32              /* <= 1 000 max num of ops per semop call */
  71 #define SEMVMX  32767           /* <= 32767 semaphore maximum value */
  72 #define SEMAEM  SEMVMX          /* adjust on exit max value */
  73
  74 /* unused */
  75 #define SEMUME  SEMOPM          /* max num of undo entries per process */
  76 #define SEMMNU  SEMMNS          /* num of undo structures system wide */
  77 #define SEMMAP  SEMMNS          /* # of entries in semaphore map */
  78 #define SEMUSZ  20              /* sizeof struct sem_undo */
  79
  80 #ifdef __KERNEL__
  81
  82 /* One semaphore structure for each semaphore in the system. */
  83 struct sem {
  84         int     semval;         /* current value */
  85         int     sempid;         /* pid of last operation */
  86 };
  87
  88 /* One sem_array data structure for each set of semaphores in the system. */
  89 struct sem_array {
  90         struct kern_ipc_perm    sem_perm;       /* permissions .. see ipc.h */
  91         time_t                  sem_otime;      /* last semop time */
  92         time_t                  sem_ctime;      /* last change time */
  93         struct sem              *sem_base;      /* ptr to first semaphore in array */
  94         struct sem_queue        *sem_pending;   /* pending operations to be processed */
  95         struct sem_queue        **sem_pending_last; /* last pending operation */
  96         struct sem_undo         *undo;          /* undo requests on this array */
  97         unsigned long           sem_nsems;      /* no. of semaphores in array */
  98 };
  99
 100 /* One queue for each sleeping process in the system. */
 101 struct sem_queue {
 102         struct sem_queue *      next;    /* next entry in the queue */
 103         struct sem_queue **     prev;    /* previous entry in the queue, *(q->prev) == q */
 104         struct task_struct*     sleeper; /* this process */
 105         struct sem_undo *       undo;    /* undo structure */
 106         int                     pid;     /* process id of requesting process */
 107         int                     status;  /* completion status of operation */
 108         struct sem_array *      sma;     /* semaphore array for operations */
 109         int                     id;      /* internal sem id */
 110         struct sembuf *         sops;    /* array of pending operations */
 111         int                     nsops;   /* number of operations */
 112         int                     alter;   /* does the operation alter the array? */
 113 };
 114
 115 /* Each task has a list of undo requests. They are executed automatically
 116  * when the process exits.
 117  */
 118 struct sem_undo {
 119         struct sem_undo *       proc_next;      /* next entry on this process */
 120         struct sem_undo *       id_next;        /* next entry on this semaphore set */
 121         int                     semid;          /* semaphore set identifier */
 122         short *                 semadj;         /* array of adjustments, one per semaphore */
 123 };
 124
 125 /* sem_undo_list controls shared access to the list of sem_undo structures
 126  * that may be shared among all a CLONE_SYSVSEM task group.
 127  */
 128 struct sem_undo_list {
 129         atomic_t        refcnt;
 130         spinlock_t      lock;
 131         struct sem_undo *proc_list;
 132 };
 133
 134 struct sysv_sem {
 135         struct sem_undo_list *undo_list;
 136 };
 137
 138 #ifdef CONFIG_SYSVIPC
 139
 140 extern int copy_semundo(unsigned long clone_flags, struct task_struct *tsk);
 141 extern void exit_sem(struct task_struct *tsk);
 142
 143 #else
 144 static inline int copy_semundo(unsigned long clone_flags, struct task_struct *tsk)
 145 {
 146         return 0;
 147 }
 148
 149 static inline void exit_sem(struct task_struct *tsk)
 150 {
 151         return;
 152 }
 153 #endif
 154
 155 #endif /* __KERNEL__ */
 156
 157 #endif /* _LINUX_SEM_H */