include/linux/sem.h

16904 #ifndef _LINUX_SEM_H
16905 #define _LINUX_SEM_H
16906 
16907 #include <linux/ipc.h>
16908 
16909 /* semop flags */
16910 #define SEM_UNDO 0x1000  /* undo the operation on exit */
16911 
16912 /* semctl Command Definitions. */
16913 #define GETPID  11       /* get sempid */
16914 #define GETVAL  12       /* get semval */
16915 #define GETALL  13       /* get all semval's */
16916 #define GETNCNT 14       /* get semncnt */
16917 #define GETZCNT 15       /* get semzcnt */
16918 #define SETVAL  16       /* set semval */
16919 #define SETALL  17       /* set all semval's */
16920 
16921 /* ipcs ctl cmds */
16922 #define SEM_STAT 18
16923 #define SEM_INFO 19
16924 
16925 /* One semid data structure for each set of semaphores in
16926    the system. */
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16927 struct semid_ds {
16928   struct ipc_perm sem_perm;  /* permissions; see ipc.h */
16929   __kernel_time_t sem_otime; /* last semop time */
16930   __kernel_time_t sem_ctime; /* last change time */
16931   struct sem      *sem_base; /* ptr to 1st sem in arr */
16932   struct sem_queue *sem_pending; /* op to be processed */
16933   struct sem_queue **sem_pending_last; /* last op */
16934   struct sem_undo *undo;     /* undo reqs on this arr */
16935   unsigned short  sem_nsems; /* # sems in array */
16936 };
16937 
16938 /* semop system calls takes an array of these. */
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16939 struct sembuf {
16940   unsigned short  sem_num;      /* sem index in array */
16941   short           sem_op;       /* semaphore operation */
16942   short           sem_flg;      /* operation flags */
16943 };
16944 
16945 /* arg for semctl system calls. */
16946 union semun {
16947   int val;                /* value for SETVAL */
16948   struct semid_ds *buf;   /* buf for IPC_STAT&IPC_SET */
16949   unsigned short *array;  /* array for GETALL & SETALL */
16950   struct seminfo *__buf;  /* buffer for IPC_INFO */
16951   void *__pad;
16952 };
16953 
16954 struct  seminfo {
16955   int semmap;
16956   int semmni;
16957   int semmns;
16958   int semmnu;
16959   int semmsl;
16960   int semopm;
16961   int semume;
16962   int semusz;
16963   int semvmx;
16964   int semaem;
16965 };
16966 
16967 #define SEMMNI  128   /* ?  max # of sem identifiers */
16968 #define SEMMSL  32    /* <= 512 max semaphores per id */
16969 #define SEMMNS  (SEMMNI*SEMMSL) /* ? max sems in system*/
16970 #define SEMOPM  32    /* ~ 100 max ops per semop call */
16971 #define SEMVMX  32767 /* semaphore maximum value */
16972 
16973 /* unused */
16974 #define SEMUME  SEMOPM /* max undo entries per process */
16975 #define SEMMNU  SEMMNS /* # undo structures sys-wide */
16976 #define SEMAEM  (SEMVMX >> 1) /* adjust on exit max val*/
16977 #define SEMMAP  SEMMNS /* # of entries in sem map */
16978 #define SEMUSZ  20     /* sizeof struct sem_undo */
16979 
16980 #ifdef __KERNEL__
16981 
16982 /* One sem structure for each sem in the system. */
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16983 struct sem {
16984   int     semval;         /* current value */
16985   int     sempid;         /* pid of last operation */
16986 };
16987 
16988 /* One queue for each semaphore set in the system. */
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16989 struct sem_queue {
16990   /* next entry in the queue */
16991   struct sem_queue *      next;
16992   /* previous entry in the queue, *(q->prev) == q */
16993   struct sem_queue **     prev;
16994   /* sleeping process */
16995   struct wait_queue *     sleeper;
16996   /* undo structure */
16997   struct sem_undo *       undo;
16998   /* process id of requesting process */
16999   int                     pid;
17000   /* completion status of operation */
17001   int                     status;
17002   /* semaphore array for operations */
17003   struct semid_ds *       sma;
17004   /* array of pending operations */
17005   struct sembuf *         sops;
17006   /* number of operations */
17007   int                     nsops;
17008   /* operation will alter semaphore */
17009   int                     alter;
17010 };
17011 
17012 /* Each task has a list of undo requests. They are
17013  * executed automatically when the process exits.  */
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17014 struct sem_undo {
17015   /* next entry on this process */
17016   struct sem_undo *       proc_next;
17017   /* next entry on this semaphore set */
17018   struct sem_undo *       id_next;
17019   /* semaphore set identifier */
17020   int                     semid;
17021   /* array of adjustments, one per semaphore */
17022   short *                 semadj;
17023 };
17024 
17025 asmlinkage int sys_semget (key_t key, int nsems,
17026                            int semflg);
17027 asmlinkage int sys_semop (int semid, struct sembuf *sops,
17028                           unsigned nsops);
17029 asmlinkage int sys_semctl (int semid, int semnum,
17030                            int cmd, union semun arg);
17031 
17032 #endif /* __KERNEL__ */
17033 
17034 #endif /* _LINUX_SEM_H */