1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
|
/*
* linux/ipc/util.c
* Copyright (C) 1992 Krishna Balasubramanian
*/
#include <linux/config.h>
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/sem.h>
#include <linux/msg.h>
#include <linux/shm.h>
#include <linux/stat.h>
#include <linux/init.h>
#include <asm/uaccess.h>
#if defined(CONFIG_SYSVIPC) || defined(CONFIG_KERNELD)
extern void sem_init (void), msg_init (void), shm_init (void);
__initfunc(void ipc_init (void))
{
sem_init();
msg_init();
shm_init();
return;
}
/*
* Check user, group, other permissions for access
* to ipc resources. return 0 if allowed
*/
int ipcperms (struct ipc_perm *ipcp, short flag)
{ /* flag will most probably be 0 or S_...UGO from <linux/stat.h> */
int requested_mode, granted_mode;
if (suser())
return 0;
requested_mode = (flag >> 6) | (flag >> 3) | flag;
granted_mode = ipcp->mode;
if (current->euid == ipcp->cuid || current->euid == ipcp->uid)
granted_mode >>= 6;
else if (in_group_p(ipcp->cgid) || in_group_p(ipcp->gid))
granted_mode >>= 3;
/* is there some bit set in requested_mode but not in granted_mode? */
if (requested_mode & ~granted_mode & 0007)
return -1;
return 0;
}
#else
/*
* Dummy functions when SYSV IPC isn't configured
*/
void sem_exit (void)
{
return;
}
int shm_swap (int prio, unsigned long limit)
{
return 0;
}
asmlinkage int sys_semget (key_t key, int nsems, int semflg)
{
return -ENOSYS;
}
asmlinkage int sys_semop (int semid, struct sembuf *sops, unsigned nsops)
{
return -ENOSYS;
}
asmlinkage int sys_semctl (int semid, int semnum, int cmd, union semun arg)
{
return -ENOSYS;
}
asmlinkage int sys_msgget (key_t key, int msgflg)
{
return -ENOSYS;
}
asmlinkage int sys_msgsnd (int msqid, struct msgbuf *msgp, size_t msgsz, int msgflg)
{
return -ENOSYS;
}
asmlinkage int sys_msgrcv (int msqid, struct msgbuf *msgp, size_t msgsz, long msgtyp,
int msgflg)
{
return -ENOSYS;
}
asmlinkage int sys_msgctl (int msqid, int cmd, struct msqid_ds *buf)
{
return -ENOSYS;
}
asmlinkage int sys_shmget (key_t key, int size, int flag)
{
return -ENOSYS;
}
asmlinkage int sys_shmat (int shmid, char *shmaddr, int shmflg, ulong *addr)
{
return -ENOSYS;
}
asmlinkage int sys_shmdt (char *shmaddr)
{
return -ENOSYS;
}
asmlinkage int sys_shmctl (int shmid, int cmd, struct shmid_ds *buf)
{
return -ENOSYS;
}
void kerneld_exit(void)
{
}
#endif /* CONFIG_SYSVIPC */
|
