Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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linux
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 */
24struct 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. */
39struct 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. */
46union 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
54struct 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
82struct task_struct;
83
84/* One semaphore structure for each semaphore in the system. */
85struct sem {
86 int semval; /* current value */
87 int sempid; /* pid of last operation */
88};
89
90/* One sem_array data structure for each set of semaphores in the system. */
91struct sem_array {
92 struct kern_ipc_perm sem_perm; /* permissions .. see ipc.h */
93 int sem_id;
94 time_t sem_otime; /* last semop time */
95 time_t sem_ctime; /* last change time */
96 struct sem *sem_base; /* ptr to first semaphore in array */
97 struct sem_queue *sem_pending; /* pending operations to be processed */
98 struct sem_queue **sem_pending_last; /* last pending operation */
99 struct sem_undo *undo; /* undo requests on this array */
100 unsigned long sem_nsems; /* no. of semaphores in array */
101};
102
103/* One queue for each sleeping process in the system. */
104struct sem_queue {
105 struct sem_queue * next; /* next entry in the queue */
106 struct sem_queue ** prev; /* previous entry in the queue, *(q->prev) == q */
107 struct task_struct* sleeper; /* this process */
108 struct sem_undo * undo; /* undo structure */
109 int pid; /* process id of requesting process */
110 int status; /* completion status of operation */
111 struct sem_array * sma; /* semaphore array for operations */
112 int id; /* internal sem id */
113 struct sembuf * sops; /* array of pending operations */
114 int nsops; /* number of operations */
115 int alter; /* does the operation alter the array? */
116};
117
118/* Each task has a list of undo requests. They are executed automatically
119 * when the process exits.
120 */
121struct sem_undo {
122 struct sem_undo * proc_next; /* next entry on this process */
123 struct sem_undo * id_next; /* next entry on this semaphore set */
124 int semid; /* semaphore set identifier */
125 short * semadj; /* array of adjustments, one per semaphore */
126};
127
128/* sem_undo_list controls shared access to the list of sem_undo structures
129 * that may be shared among all a CLONE_SYSVSEM task group.
130 */
131struct sem_undo_list {
132 atomic_t refcnt;
133 spinlock_t lock;
134 struct sem_undo *proc_list;
135};
136
137struct sysv_sem {
138 struct sem_undo_list *undo_list;
139};
140
141#ifdef CONFIG_SYSVIPC
142
143extern int copy_semundo(unsigned long clone_flags, struct task_struct *tsk);
144extern void exit_sem(struct task_struct *tsk);
145
146#else
147static inline int copy_semundo(unsigned long clone_flags, struct task_struct *tsk)
148{
149 return 0;
150}
151
152static inline void exit_sem(struct task_struct *tsk)
153{
154 return;
155}
156#endif
157
158#endif /* __KERNEL__ */
159
160#endif /* _LINUX_SEM_H */