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#ifndef _LINUX_SEM_H
#define _LINUX_SEM_H
#include <linux/ipc.h>
/* semop flags */
#define SEM_UNDO 0x1000 /* undo the operation on exit */
/* semctl Command Definitions. */
#define GETPID 11 /* get sempid */
#define GETVAL 12 /* get semval */
#define GETALL 13 /* get all semval's */
#define GETNCNT 14 /* get semncnt */
#define GETZCNT 15 /* get semzcnt */
#define SETVAL 16 /* set semval */
#define SETALL 17 /* set all semval's */
/* ipcs ctl cmds */
#define SEM_STAT 18
#define SEM_INFO 19
/* One semid data structure for each set of semaphores in the system. */
struct semid_ds {
struct ipc_perm sem_perm; /* permissions .. see ipc.h */
__kernel_time_t sem_otime; /* last semop time */
__kernel_time_t sem_ctime; /* last change time */
struct sem *sem_base; /* ptr to first semaphore in array */
struct sem_queue *sem_pending; /* pending operations to be processed */
struct sem_queue **sem_pending_last; /* last pending operation */
struct sem_undo *undo; /* undo requests on this array */
unsigned short sem_nsems; /* no. of semaphores in array */
};
/* semop system calls takes an array of these. */
struct sembuf {
unsigned short sem_num; /* semaphore index in array */
short sem_op; /* semaphore operation */
short sem_flg; /* operation flags */
};
/* arg for semctl system calls. */
union semun {
int val; /* value for SETVAL */
struct semid_ds *buf; /* buffer for IPC_STAT & IPC_SET */
unsigned short *array; /* array for GETALL & SETALL */
struct seminfo *__buf; /* buffer for IPC_INFO */
void *__pad;
};
struct seminfo {
int semmap;
int semmni;
int semmns;
int semmnu;
int semmsl;
int semopm;
int semume;
int semusz;
int semvmx;
int semaem;
};
#define SEMMNI 128 /* ? max # of semaphore identifiers */
#define SEMMSL 250 /* <= 512 max num of semaphores per id */
#define SEMMNS (SEMMNI*SEMMSL) /* ? max # of semaphores in system */
#define SEMOPM 32 /* ~ 100 max num of ops per semop call */
#define SEMVMX 32767 /* semaphore maximum value */
/* unused */
#define SEMUME SEMOPM /* max num of undo entries per process */
#define SEMMNU SEMMNS /* num of undo structures system wide */
#define SEMAEM (SEMVMX >> 1) /* adjust on exit max value */
#define SEMMAP SEMMNS /* # of entries in semaphore map */
#define SEMUSZ 20 /* sizeof struct sem_undo */
#ifdef __KERNEL__
/* One semaphore structure for each semaphore in the system. */
struct sem {
int semval; /* current value */
int sempid; /* pid of last operation */
};
/* One queue for each semaphore set in the system. */
struct sem_queue {
struct sem_queue * next; /* next entry in the queue */
struct sem_queue ** prev; /* previous entry in the queue, *(q->prev) == q */
struct wait_queue * sleeper; /* sleeping process */
struct sem_undo * undo; /* undo structure */
int pid; /* process id of requesting process */
int status; /* completion status of operation */
struct semid_ds * sma; /* semaphore array for operations */
struct sembuf * sops; /* array of pending operations */
int nsops; /* number of operations */
int alter; /* operation will alter semaphore */
};
/* Each task has a list of undo requests. They are executed automatically
* when the process exits.
*/
struct sem_undo {
struct sem_undo * proc_next; /* next entry on this process */
struct sem_undo * id_next; /* next entry on this semaphore set */
int semid; /* semaphore set identifier */
short * semadj; /* array of adjustments, one per semaphore */
};
asmlinkage int sys_semget (key_t key, int nsems, int semflg);
asmlinkage int sys_semop (int semid, struct sembuf *sops, unsigned nsops);
asmlinkage int sys_semctl (int semid, int semnum, int cmd, union semun arg);
#endif /* __KERNEL__ */
#endif /* _LINUX_SEM_H */
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