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