root/ipc/util.c

/* */

DEFINITIONS

1. ipc_init
2. ipcperms
3. sys_ipc
4. sys_ipc
5. shm_fork
6. sem_exit
7. shm_exit
8. shm_swap
9. shm_no_page

   1 /*
   2  * linux/ipc/util.c
   3  * Copyright (C) 1992 Krishna Balasubramanian
   4  */
   5 
   6 #include <linux/config.h>
   7 #include <linux/errno.h>
   8 #include <asm/segment.h>
   9 #include <linux/sched.h>
  10 #include <linux/sem.h>
  11 #include <linux/msg.h>
  12 #include <linux/shm.h>
  13 #include <linux/stat.h>
  14 
  15 void ipc_init (void);
  16 asmlinkage int sys_ipc (uint call, int first, int second, int third, void *ptr); 
  17 
  18 #ifdef CONFIG_SYSVIPC
  19 
  20 int ipcperms (struct ipc_perm *ipcp, short flag);
  21 extern void sem_init (void), msg_init (void), shm_init (void);
  22 extern int sys_semget (key_t key, int nsems, int semflg);
  23 extern int sys_semop (int semid, struct sembuf *sops, unsigned nsops);
  24 extern int sys_semctl (int semid, int semnum, int cmd, void *arg);
  25 extern int sys_msgget (key_t key, int msgflg);
  26 extern int sys_msgsnd (int msqid, struct msgbuf *msgp, int msgsz, int msgflg);
  27 extern int sys_msgrcv (int msqid, struct msgbuf *msgp, int msgsz, long msgtyp,
  28                        int msgflg);
  29 extern int sys_msgctl (int msqid, int cmd, struct msqid_ds *buf);
  30 extern int sys_shmctl (int shmid, int cmd, struct shmid_ds *buf);
  31 extern int sys_shmget (key_t key, int size, int flag);
  32 extern int sys_shmat (int shmid, char *shmaddr, int shmflg, ulong *addr);
  33 extern int sys_shmdt (char *shmaddr);
  34 
  35 void ipc_init (void)
     /*  */
  36 {
  37         sem_init();
  38         msg_init();
  39         shm_init();
  40         return;
  41 }
  42 
  43 /* 
  44  * Check user, group, other permissions for access
  45  * to ipc resources. return 0 if allowed
  46  */
  47 int ipcperms (struct ipc_perm *ipcp, short flag)
     /*  */
  48 {
  49         int i; mode_t perm; uid_t euid; int egid;
  50         
  51         if (suser())
  52                 return 0;
  53 
  54         perm = S_IRWXO; euid = current->euid;
  55 
  56         if (euid == ipcp->cuid || euid == ipcp->uid) 
  57                 perm = S_IRWXU;
  58         else {
  59                 for (i = 0; (egid = current->groups[i]) != NOGROUP; i++)
  60                         if ((egid == ipcp->cgid) || (egid == ipcp->gid)) { 
  61                                 perm = S_IRWXG; 
  62                                 break;
  63                         }
  64         }
  65         if (!(flag & perm) || flag & perm & ~ipcp->mode)
  66                 return -1;
  67         return 0;
  68 }
  69 
  70 asmlinkage int sys_ipc (uint call, int first, int second, int third, void *ptr) 
     /*  */
  71 {
  72         
  73         if (call <= SEMCTL)
  74                 switch (call) {
  75                 case SEMOP:
  76                         return sys_semop (first, (struct sembuf *)ptr, second);
  77                 case SEMGET:
  78                         return sys_semget (first, second, third);
  79                 case SEMCTL:
  80                         return sys_semctl (first, second, third, ptr);
  81                 default:
  82                         return -EINVAL;
  83                 }
  84         if (call <= MSGCTL) 
  85                 switch (call) {
  86                 case MSGSND:
  87                         return sys_msgsnd (first, (struct msgbuf *) ptr, 
  88                                            second, third);
  89                 case MSGRCV: {
  90                         struct ipc_kludge tmp; 
  91                         if (!ptr)
  92                                 return -EINVAL;
  93                         memcpy_fromfs (&tmp,(struct ipc_kludge *) ptr, 
  94                                        sizeof (tmp));
  95                         return sys_msgrcv (first, tmp.msgp, second, tmp.msgtyp,
  96                                                 third);
  97                         }
  98                 case MSGGET:
  99                         return sys_msgget ((key_t) first, second);
 100                 case MSGCTL:
 101                         return sys_msgctl (first, second, 
 102                                                 (struct msqid_ds *) ptr);
 103                 default:
 104                         return -EINVAL;
 105                 }
 106         if (call <= SHMCTL) 
 107                 switch (call) {
 108                 case SHMAT: /* returning shmaddr > 2G will screw up */
 109                         return sys_shmat (first, (char *) ptr, second, 
 110                                                         (ulong *) third);
 111                 case SHMDT: 
 112                         return sys_shmdt ((char *)ptr);
 113                 case SHMGET:
 114                         return sys_shmget (first, second, third);
 115                 case SHMCTL:
 116                         return sys_shmctl (first, second, 
 117                                                 (struct shmid_ds *) ptr);
 118                 default:
 119                         return -EINVAL;
 120                 }
 121         return -EINVAL;
 122 }
 123 
 124 #else /* not CONFIG_SYSVIPC */
 125 
 126 asmlinkage int sys_ipc (uint call, int first, int second, int third, void *ptr) 
     /*  */
 127 {
 128     return -ENOSYS;
 129 }
 130 
 131 int shm_fork (struct task_struct *p1, struct task_struct *p2)
     /*  */
 132 {
 133     return 0;
 134 }
 135 
 136 void sem_exit (void)
     /*  */
 137 {
 138     return;
 139 }
 140 
 141 void shm_exit (void)
     /*  */
 142 {
 143     return;
 144 }
 145 
 146 int shm_swap (int prio)
     /*  */
 147 {
 148     return 0;
 149 }
 150 
 151 void shm_no_page (unsigned long *ptent)
     /*  */
 152 {
 153     return;
 154 }
 155 
 156 #endif /* CONFIG_SYSVIPC */

/* */