ipc/syscall.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * sys_ipc() is the old de-multiplexer for the SysV IPC calls.
   4  *
   5  * This is really horribly ugly, and new architectures should just wire up
   6  * the individual syscalls instead.
   7  */
   8 #include <linux/unistd.h>
   9 #include <linux/syscalls.h>
  10
  11 #ifdef __ARCH_WANT_SYS_IPC
  12 #include <linux/errno.h>
  13 #include <linux/ipc.h>
  14 #include <linux/shm.h>
  15 #include <linux/uaccess.h>
  16
  17 SYSCALL_DEFINE6(ipc, unsigned int, call, int, first, unsigned long, second,
  18                 unsigned long, third, void __user *, ptr, long, fifth)
  19 {
  20         int version, ret;
  21
  22         version = call >> 16; /* hack for backward compatibility */
  23         call &= 0xffff;
  24
  25         switch (call) {
  26         case SEMOP:
  27                 return sys_semtimedop(first, (struct sembuf __user *)ptr,
  28                                       second, NULL);
  29         case SEMTIMEDOP:
  30                 return sys_semtimedop(first, (struct sembuf __user *)ptr,
  31                                       second,
  32                                       (const struct timespec __user *)fifth);
  33
  34         case SEMGET:
  35                 return sys_semget(first, second, third);
  36         case SEMCTL: {
  37                 unsigned long arg;
  38                 if (!ptr)
  39                         return -EINVAL;
  40                 if (get_user(arg, (unsigned long __user *) ptr))
  41                         return -EFAULT;
  42                 return sys_semctl(first, second, third, arg);
  43         }
  44
  45         case MSGSND:
  46                 return sys_msgsnd(first, (struct msgbuf __user *) ptr,
  47                                   second, third);
  48         case MSGRCV:
  49                 switch (version) {
  50                 case 0: {
  51                         struct ipc_kludge tmp;
  52                         if (!ptr)
  53                                 return -EINVAL;
  54
  55                         if (copy_from_user(&tmp,
  56                                            (struct ipc_kludge __user *) ptr,
  57                                            sizeof(tmp)))
  58                                 return -EFAULT;
  59                         return sys_msgrcv(first, tmp.msgp, second,
  60                                            tmp.msgtyp, third);
  61                 }
  62                 default:
  63                         return sys_msgrcv(first,
  64                                            (struct msgbuf __user *) ptr,
  65                                            second, fifth, third);
  66                 }
  67         case MSGGET:
  68                 return sys_msgget((key_t) first, second);
  69         case MSGCTL:
  70                 return sys_msgctl(first, second, (struct msqid_ds __user *)ptr);
  71
  72         case SHMAT:
  73                 switch (version) {
  74                 default: {
  75                         unsigned long raddr;
  76                         ret = do_shmat(first, (char __user *)ptr,
  77                                        second, &raddr, SHMLBA);
  78                         if (ret)
  79                                 return ret;
  80                         return put_user(raddr, (unsigned long __user *) third);
  81                 }
  82                 case 1:
  83                         /*
  84                          * This was the entry point for kernel-originating calls
  85                          * from iBCS2 in 2.2 days.
  86                          */
  87                         return -EINVAL;
  88                 }
  89         case SHMDT:
  90                 return sys_shmdt((char __user *)ptr);
  91         case SHMGET:
  92                 return sys_shmget(first, second, third);
  93         case SHMCTL:
  94                 return sys_shmctl(first, second,
  95                                    (struct shmid_ds __user *) ptr);
  96         default:
  97                 return -ENOSYS;
  98         }
  99 }
 100 #endif
 101
 102 #ifdef CONFIG_COMPAT
 103 #include <linux/compat.h>
 104
 105 #ifndef COMPAT_SHMLBA
 106 #define COMPAT_SHMLBA   SHMLBA
 107 #endif
 108
 109 struct compat_ipc_kludge {
 110         compat_uptr_t msgp;
 111         compat_long_t msgtyp;
 112 };
 113
 114 #ifdef CONFIG_ARCH_WANT_OLD_COMPAT_IPC
 115 COMPAT_SYSCALL_DEFINE6(ipc, u32, call, int, first, int, second,
 116         u32, third, compat_uptr_t, ptr, u32, fifth)
 117 {
 118         int version;
 119         u32 pad;
 120
 121         version = call >> 16; /* hack for backward compatibility */
 122         call &= 0xffff;
 123
 124         switch (call) {
 125         case SEMOP:
 126                 /* struct sembuf is the same on 32 and 64bit :)) */
 127                 return sys_semtimedop(first, compat_ptr(ptr), second, NULL);
 128         case SEMTIMEDOP:
 129                 return compat_sys_semtimedop(first, compat_ptr(ptr), second,
 130                                                 compat_ptr(fifth));
 131         case SEMGET:
 132                 return sys_semget(first, second, third);
 133         case SEMCTL:
 134                 if (!ptr)
 135                         return -EINVAL;
 136                 if (get_user(pad, (u32 __user *) compat_ptr(ptr)))
 137                         return -EFAULT;
 138                 return compat_sys_semctl(first, second, third, pad);
 139
 140         case MSGSND:
 141                 return compat_sys_msgsnd(first, ptr, second, third);
 142
 143         case MSGRCV: {
 144                 void __user *uptr = compat_ptr(ptr);
 145
 146                 if (first < 0 || second < 0)
 147                         return -EINVAL;
 148
 149                 if (!version) {
 150                         struct compat_ipc_kludge ipck;
 151                         if (!uptr)
 152                                 return -EINVAL;
 153                         if (copy_from_user(&ipck, uptr, sizeof(ipck)))
 154                                 return -EFAULT;
 155                         return compat_sys_msgrcv(first, ipck.msgp, second,
 156                                                  ipck.msgtyp, third);
 157                 }
 158                 return compat_sys_msgrcv(first, ptr, second, fifth, third);
 159         }
 160         case MSGGET:
 161                 return sys_msgget(first, second);
 162         case MSGCTL:
 163                 return compat_sys_msgctl(first, second, compat_ptr(ptr));
 164
 165         case SHMAT: {
 166                 int err;
 167                 unsigned long raddr;
 168
 169                 if (version == 1)
 170                         return -EINVAL;
 171                 err = do_shmat(first, compat_ptr(ptr), second, &raddr,
 172                                COMPAT_SHMLBA);
 173                 if (err < 0)
 174                         return err;
 175                 return put_user(raddr, (compat_ulong_t __user *)compat_ptr(third));
 176         }
 177         case SHMDT:
 178                 return sys_shmdt(compat_ptr(ptr));
 179         case SHMGET:
 180                 return sys_shmget(first, (unsigned)second, third);
 181         case SHMCTL:
 182                 return compat_sys_shmctl(first, second, compat_ptr(ptr));
 183         }
 184
 185         return -ENOSYS;
 186 }
 187 #endif
 188 #endif