sysdeps/unix/sysv/linux/shmctl.c

   1 /* Copyright (C) 1995-2015 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Ulrich Drepper <drepper@gnu.ai.mit.edu>, August 1995.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <errno.h>
  20 #include <sys/shm.h>
  21 #include <ipc_priv.h>
  22
  23 #include <sysdep.h>
  24 #include <string.h>
  25 #include <sys/syscall.h>
  26 #include <bits/wordsize.h>
  27 #include <shlib-compat.h>
  28
  29 #include <kernel-features.h>
  30
  31 struct __old_shmid_ds
  32 {
  33   struct __old_ipc_perm shm_perm;       /* operation permission struct */
  34   int shm_segsz;                        /* size of segment in bytes */
  35   __time_t shm_atime;                   /* time of last shmat() */
  36   __time_t shm_dtime;                   /* time of last shmdt() */
  37   __time_t shm_ctime;                   /* time of last change by shmctl() */
  38   __ipc_pid_t shm_cpid;                 /* pid of creator */
  39   __ipc_pid_t shm_lpid;                 /* pid of last shmop */
  40   unsigned short int shm_nattch;        /* number of current attaches */
  41   unsigned short int __shm_npages;      /* size of segment (pages) */
  42   unsigned long int *__shm_pages;       /* array of ptrs to frames -> SHMMAX */
  43   struct vm_area_struct *__attaches;    /* descriptors for attaches */
  44 };
  45
  46 struct __old_shminfo
  47 {
  48   int shmmax;
  49   int shmmin;
  50   int shmmni;
  51   int shmseg;
  52   int shmall;
  53 };
  54
  55 /* Provide operations to control over shared memory segments.  */
  56 #if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_2)
  57 int __old_shmctl (int, int, struct __old_shmid_ds *);
  58 #endif
  59 int __new_shmctl (int, int, struct shmid_ds *);
  60
  61 #if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_2)
  62 int
  63 attribute_compat_text_section
  64 __old_shmctl (int shmid, int cmd, struct __old_shmid_ds *buf)
  65 {
  66   return INLINE_SYSCALL (ipc, 5, IPCOP_shmctl, shmid, cmd, 0, buf);
  67 }
  68 compat_symbol (libc, __old_shmctl, shmctl, GLIBC_2_0);
  69 #endif
  70
  71 int
  72 __new_shmctl (int shmid, int cmd, struct shmid_ds *buf)
  73 {
  74 #if __ASSUME_IPC64 > 0
  75   return INLINE_SYSCALL (ipc, 5, IPCOP_shmctl, shmid, cmd | __IPC_64, 0,
  76                          buf);
  77 #else
  78   switch (cmd) {
  79     case SHM_STAT:
  80     case IPC_STAT:
  81     case IPC_SET:
  82 #if __WORDSIZE != 32
  83     case IPC_INFO:
  84 #endif
  85       break;
  86     default:
  87       return INLINE_SYSCALL (ipc, 5, IPCOP_shmctl, shmid, cmd, 0, buf);
  88   }
  89
  90   {
  91     int save_errno = errno, result;
  92     union
  93       {
  94         struct __old_shmid_ds ds;
  95         struct __old_shminfo info;
  96       } old;
  97
  98     /* Unfortunately there is no way how to find out for sure whether
  99        we should use old or new shmctl.  */
 100     result = INLINE_SYSCALL (ipc, 5, IPCOP_shmctl, shmid, cmd | __IPC_64, 0,
 101                              buf);
 102     if (result != -1 || errno != EINVAL)
 103       return result;
 104
 105     __set_errno(save_errno);
 106     if (cmd == IPC_SET)
 107       {
 108         old.ds.shm_perm.uid = buf->shm_perm.uid;
 109         old.ds.shm_perm.gid = buf->shm_perm.gid;
 110         old.ds.shm_perm.mode = buf->shm_perm.mode;
 111         if (old.ds.shm_perm.uid != buf->shm_perm.uid ||
 112             old.ds.shm_perm.gid != buf->shm_perm.gid)
 113           {
 114             __set_errno (EINVAL);
 115             return -1;
 116           }
 117       }
 118     result = INLINE_SYSCALL (ipc, 5, IPCOP_shmctl, shmid, cmd, 0, &old.ds);
 119     if (result != -1 && (cmd == SHM_STAT || cmd == IPC_STAT))
 120       {
 121         memset(buf, 0, sizeof(*buf));
 122         buf->shm_perm.__key = old.ds.shm_perm.__key;
 123         buf->shm_perm.uid = old.ds.shm_perm.uid;
 124         buf->shm_perm.gid = old.ds.shm_perm.gid;
 125         buf->shm_perm.cuid = old.ds.shm_perm.cuid;
 126         buf->shm_perm.cgid = old.ds.shm_perm.cgid;
 127         buf->shm_perm.mode = old.ds.shm_perm.mode;
 128         buf->shm_perm.__seq = old.ds.shm_perm.__seq;
 129         buf->shm_atime = old.ds.shm_atime;
 130         buf->shm_dtime = old.ds.shm_dtime;
 131         buf->shm_ctime = old.ds.shm_ctime;
 132         buf->shm_segsz = old.ds.shm_segsz;
 133         buf->shm_nattch = old.ds.shm_nattch;
 134         buf->shm_cpid = old.ds.shm_cpid;
 135         buf->shm_lpid = old.ds.shm_lpid;
 136       }
 137 #if __WORDSIZE != 32
 138     else if (result != -1 && cmd == IPC_INFO)
 139       {
 140         struct shminfo *i = (struct shminfo *)buf;
 141
 142         memset(i, 0, sizeof(*i));
 143         i->shmmax = old.info.shmmax;
 144         i->shmmin = old.info.shmmin;
 145         i->shmmni = old.info.shmmni;
 146         i->shmseg = old.info.shmseg;
 147         i->shmall = old.info.shmall;
 148       }
 149 #endif
 150     return result;
 151   }
 152 #endif
 153 }
 154
 155 versioned_symbol (libc, __new_shmctl, shmctl, GLIBC_2_2);