ipc/util.c

   1 /*
   2  * linux/ipc/util.c
   3  * Copyright (C) 1992 Krishna Balasubramanian
   4  *
   5  * Sep 1997 - Call suser() last after "normal" permission checks so we
   6  *            get BSD style process accounting right.
   7  *            Occurs in several places in the IPC code.
   8  *            Chris Evans, <chris@ferret.lmh.ox.ac.uk>
   9  */
  10
  11 #include <linux/config.h>
  12 #include <linux/errno.h>
  13 #include <linux/sched.h>
  14 #include <linux/mm.h>
  15 #include <linux/sem.h>
  16 #include <linux/msg.h>
  17 #include <linux/shm.h>
  18 #include <linux/stat.h>
  19 #include <linux/init.h>
  20
  21 #include <asm/uaccess.h>
  22
  23 #if defined(CONFIG_SYSVIPC)
  24
  25 extern void sem_init (void), msg_init (void), shm_init (void);
  26
  27 void __init ipc_init (void)
  28 {
  29         sem_init();
  30         msg_init();
  31         shm_init();
  32         return;
  33 }
  34
  35 /*
  36  * Check user, group, other permissions for access
  37  * to ipc resources. return 0 if allowed
  38  */
  39 int ipcperms (struct ipc_perm *ipcp, short flag)
  40 {       /* flag will most probably be 0 or S_...UGO from <linux/stat.h> */
  41         int requested_mode, granted_mode;
  42
  43         requested_mode = (flag >> 6) | (flag >> 3) | flag;
  44         granted_mode = ipcp->mode;
  45         if (current->euid == ipcp->cuid || current->euid == ipcp->uid)
  46                 granted_mode >>= 6;
  47         else if (in_group_p(ipcp->cgid) || in_group_p(ipcp->gid))
  48                 granted_mode >>= 3;
  49         /* is there some bit set in requested_mode but not in granted_mode? */
  50         if ((requested_mode & ~granted_mode & 0007) &&
  51             !capable(CAP_IPC_OWNER))
  52                 return -1;
  53
  54         return 0;
  55 }
  56
  57 #else
  58 /*
  59  * Dummy functions when SYSV IPC isn't configured
  60  */
  61
  62 void sem_exit (void)
  63 {
  64     return;
  65 }
  66
  67 int shm_swap (int prio, int gfp_mask)
  68 {
  69     return 0;
  70 }
  71
  72 asmlinkage int sys_semget (key_t key, int nsems, int semflg)
  73 {
  74         return -ENOSYS;
  75 }
  76
  77 asmlinkage int sys_semop (int semid, struct sembuf *sops, unsigned nsops)
  78 {
  79         return -ENOSYS;
  80 }
  81
  82 asmlinkage int sys_semctl (int semid, int semnum, int cmd, union semun arg)
  83 {
  84         return -ENOSYS;
  85 }
  86
  87 asmlinkage int sys_msgget (key_t key, int msgflg)
  88 {
  89         return -ENOSYS;
  90 }
  91
  92 asmlinkage int sys_msgsnd (int msqid, struct msgbuf *msgp, size_t msgsz, int msgflg)
  93 {
  94         return -ENOSYS;
  95 }
  96
  97 asmlinkage int sys_msgrcv (int msqid, struct msgbuf *msgp, size_t msgsz, long msgtyp,
  98                        int msgflg)
  99 {
 100         return -ENOSYS;
 101 }
 102
 103 asmlinkage int sys_msgctl (int msqid, int cmd, struct msqid_ds *buf)
 104 {
 105         return -ENOSYS;
 106 }
 107
 108 asmlinkage int sys_shmget (key_t key, int size, int flag)
 109 {
 110         return -ENOSYS;
 111 }
 112
 113 asmlinkage int sys_shmat (int shmid, char *shmaddr, int shmflg, ulong *addr)
 114 {
 115         return -ENOSYS;
 116 }
 117
 118 asmlinkage int sys_shmdt (char *shmaddr)
 119 {
 120         return -ENOSYS;
 121 }
 122
 123 asmlinkage int sys_shmctl (int shmid, int cmd, struct shmid_ds *buf)
 124 {
 125         return -ENOSYS;
 126 }
 127
 128 #endif /* CONFIG_SYSVIPC */