sysdeps/unix/sysv/linux/i386/shmctl.c

   1 /* Copyright (C) 1995, 1997, 1998, 2000 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, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #include <errno.h>
  21 #include <sys/shm.h>
  22 #include <ipc_priv.h>
  23
  24 #include <sysdep.h>
  25 #include <string.h>
  26 #include <sys/syscall.h>
  27 #include <bits/wordsize.h>
  28 #include <bp-checks.h>
  29
  30 #include "kernel-features.h"
  31 #include <shlib-compat.h>
  32
  33 struct __old_shmid_ds
  34 {
  35   struct __old_ipc_perm shm_perm;       /* operation permission struct */
  36   int shm_segsz;                        /* size of segment in bytes */
  37   __time_t shm_atime;                   /* time of last shmat() */
  38   __time_t shm_dtime;                   /* time of last shmdt() */
  39   __time_t shm_ctime;                   /* time of last change by shmctl() */
  40   __ipc_pid_t shm_cpid;                 /* pid of creator */
  41   __ipc_pid_t shm_lpid;                 /* pid of last shmop */
  42   unsigned short int shm_nattch;        /* number of current attaches */
  43   unsigned short int __shm_npages;      /* size of segment (pages) */
  44   unsigned long int *__unbounded __shm_pages; /* array of ptrs to frames -> SHMMAX */
  45   struct vm_area_struct *__unbounded __attaches; /* descriptors for attaches */
  46 };
  47
  48 struct __old_shminfo
  49 {
  50   int shmmax;
  51   int shmmin;
  52   int shmmni;
  53   int shmseg;
  54   int shmall;
  55 };
  56
  57 #ifdef __NR_getuid32
  58 # if __ASSUME_32BITUIDS == 0
  59 /* This variable is shared with all files that need to check for 32bit
  60    uids.  */
  61 extern int __libc_missing_32bit_uids;
  62 # endif
  63 #endif
  64
  65 /* Provide operations to control over shared memory segments.  */
  66 #if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_2)
  67 int __old_shmctl (int, int, struct __old_shmid_ds *);
  68 #endif
  69 int __new_shmctl (int, int, struct shmid_ds *);
  70
  71 #if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_2)
  72 int
  73 __old_shmctl (int shmid, int cmd, struct __old_shmid_ds *buf)
  74 {
  75   return INLINE_SYSCALL (ipc, 5, IPCOP_shmctl,
  76                          shmid, cmd, 0, CHECK_1 (buf));
  77 }
  78 compat_symbol (libc, __old_shmctl, shmctl, GLIBC_2_0);
  79 #endif
  80
  81 int
  82 __new_shmctl (int shmid, int cmd, struct shmid_ds *buf)
  83 {
  84 #if __ASSUME_32BITUIDS > 0
  85   return INLINE_SYSCALL (ipc, 5, IPCOP_shmctl,
  86                          shmid, cmd | __IPC_64, 0, CHECK_1 (buf));
  87 #else
  88   switch (cmd) {
  89     case SHM_STAT:
  90     case IPC_STAT:
  91     case IPC_SET:
  92 # if __WORDSIZE != 32
  93     case IPC_INFO:
  94 # endif
  95       break;
  96     default:
  97       return INLINE_SYSCALL (ipc, 5, IPCOP_shmctl,
  98                              shmid, cmd, 0, CHECK_1 (buf));
  99   }
 100
 101   {
 102     struct __old_shmid_ds old;
 103     int result;
 104
 105 # ifdef __NR_getuid32
 106     if (__libc_missing_32bit_uids <= 0)
 107       {
 108         if (__libc_missing_32bit_uids < 0)
 109           {
 110             int save_errno = errno;
 111
 112             /* Test presence of new IPC by testing for getuid32 syscall.  */
 113             result = INLINE_SYSCALL (getuid32, 0);
 114             if (result == -1 && errno == ENOSYS)
 115               __libc_missing_32bit_uids = 1;
 116             else
 117               __libc_missing_32bit_uids = 0;
 118             __set_errno(save_errno);
 119           }
 120         if (__libc_missing_32bit_uids <= 0)
 121           return INLINE_SYSCALL (ipc, 5, IPCOP_shmctl,
 122                                  shmid, cmd | __IPC_64, 0, CHECK_1 (buf));
 123       }
 124 # endif
 125
 126     if (cmd == IPC_SET)
 127       {
 128         old.shm_perm.uid = buf->shm_perm.uid;
 129         old.shm_perm.gid = buf->shm_perm.gid;
 130         old.shm_perm.mode = buf->shm_perm.mode;
 131         if (old.shm_perm.uid != buf->shm_perm.uid ||
 132             old.shm_perm.gid != buf->shm_perm.gid)
 133           {
 134             __set_errno (EINVAL);
 135             return -1;
 136           }
 137       }
 138     result = INLINE_SYSCALL (ipc, 5, IPCOP_shmctl,
 139                              shmid, cmd, 0, __ptrvalue (&old));
 140     if (result != -1 && (cmd == SHM_STAT || cmd == IPC_STAT))
 141       {
 142         memset(buf, 0, sizeof(*buf));
 143         buf->shm_perm.__key = old.shm_perm.__key;
 144         buf->shm_perm.uid = old.shm_perm.uid;
 145         buf->shm_perm.gid = old.shm_perm.gid;
 146         buf->shm_perm.cuid = old.shm_perm.cuid;
 147         buf->shm_perm.cgid = old.shm_perm.cgid;
 148         buf->shm_perm.mode = old.shm_perm.mode;
 149         buf->shm_perm.__seq = old.shm_perm.__seq;
 150         buf->shm_atime = old.shm_atime;
 151         buf->shm_dtime = old.shm_dtime;
 152         buf->shm_ctime = old.shm_ctime;
 153         buf->shm_segsz = old.shm_segsz;
 154         buf->shm_nattch = old.shm_nattch;
 155         buf->shm_cpid = old.shm_cpid;
 156         buf->shm_lpid = old.shm_lpid;
 157       }
 158 # if __WORDSIZE != 32
 159     else if (result != -1 && cmd == IPC_INFO)
 160       {
 161         struct __old_shminfo *oldi = (struct __old_shminfo *)&old;
 162         struct shminfo *i = (struct shminfo *)buf;
 163
 164         memset(i, 0, sizeof(*i));
 165         i->shmmax = oldi->shmmax;
 166         i->shmmin = oldi->shmmin;
 167         i->shmmni = oldi->shmmni;
 168         i->shmseg = oldi->shmseg;
 169         i->shmall = oldi->shmall;
 170       }
 171 # endif
 172     return result;
 173   }
 174 #endif
 175 }
 176
 177 versioned_symbol (libc, __new_shmctl, shmctl, GLIBC_2_2);