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

   1 /* Copyright (C) 1995,1997,1998,2000,2004,2006 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 attribute_compat_text_section
  74 __old_shmctl (int shmid, int cmd, struct __old_shmid_ds *buf)
  75 {
  76   return INLINE_SYSCALL (ipc, 5, IPCOP_shmctl,
  77                          shmid, cmd, 0, CHECK_1 (buf));
  78 }
  79 compat_symbol (libc, __old_shmctl, shmctl, GLIBC_2_0);
  80 #endif
  81
  82 int
  83 __new_shmctl (int shmid, int cmd, struct shmid_ds *buf)
  84 {
  85 #if __ASSUME_32BITUIDS > 0
  86   return INLINE_SYSCALL (ipc, 5, IPCOP_shmctl,
  87                          shmid, cmd | __IPC_64, 0, CHECK_1 (buf));
  88 #else
  89   switch (cmd) {
  90     case SHM_STAT:
  91     case IPC_STAT:
  92     case IPC_SET:
  93 # if __WORDSIZE != 32
  94     case IPC_INFO:
  95 # endif
  96       break;
  97     default:
  98       return INLINE_SYSCALL (ipc, 5, IPCOP_shmctl,
  99                              shmid, cmd, 0, CHECK_1 (buf));
 100   }
 101
 102   {
 103     struct __old_shmid_ds old;
 104     int result;
 105
 106 # ifdef __NR_getuid32
 107     if (__libc_missing_32bit_uids <= 0)
 108       {
 109         if (__libc_missing_32bit_uids < 0)
 110           {
 111             int save_errno = errno;
 112
 113             /* Test presence of new IPC by testing for getuid32 syscall.  */
 114             result = INLINE_SYSCALL (getuid32, 0);
 115             if (result == -1 && errno == ENOSYS)
 116               __libc_missing_32bit_uids = 1;
 117             else
 118               __libc_missing_32bit_uids = 0;
 119             __set_errno(save_errno);
 120           }
 121         if (__libc_missing_32bit_uids <= 0)
 122           return INLINE_SYSCALL (ipc, 5, IPCOP_shmctl,
 123                                  shmid, cmd | __IPC_64, 0, CHECK_1 (buf));
 124       }
 125 # endif
 126
 127     if (cmd == IPC_SET)
 128       {
 129         old.shm_perm.uid = buf->shm_perm.uid;
 130         old.shm_perm.gid = buf->shm_perm.gid;
 131         old.shm_perm.mode = buf->shm_perm.mode;
 132         if (old.shm_perm.uid != buf->shm_perm.uid ||
 133             old.shm_perm.gid != buf->shm_perm.gid)
 134           {
 135             __set_errno (EINVAL);
 136             return -1;
 137           }
 138       }
 139     result = INLINE_SYSCALL (ipc, 5, IPCOP_shmctl,
 140                              shmid, cmd, 0, __ptrvalue (&old));
 141     if (result != -1 && (cmd == SHM_STAT || cmd == IPC_STAT))
 142       {
 143         memset(buf, 0, sizeof(*buf));
 144         buf->shm_perm.__key = old.shm_perm.__key;
 145         buf->shm_perm.uid = old.shm_perm.uid;
 146         buf->shm_perm.gid = old.shm_perm.gid;
 147         buf->shm_perm.cuid = old.shm_perm.cuid;
 148         buf->shm_perm.cgid = old.shm_perm.cgid;
 149         buf->shm_perm.mode = old.shm_perm.mode;
 150         buf->shm_perm.__seq = old.shm_perm.__seq;
 151         buf->shm_atime = old.shm_atime;
 152         buf->shm_dtime = old.shm_dtime;
 153         buf->shm_ctime = old.shm_ctime;
 154         buf->shm_segsz = old.shm_segsz;
 155         buf->shm_nattch = old.shm_nattch;
 156         buf->shm_cpid = old.shm_cpid;
 157         buf->shm_lpid = old.shm_lpid;
 158       }
 159 # if __WORDSIZE != 32
 160     else if (result != -1 && cmd == IPC_INFO)
 161       {
 162         struct __old_shminfo *oldi = (struct __old_shminfo *)&old;
 163         struct shminfo *i = (struct shminfo *)buf;
 164
 165         memset(i, 0, sizeof(*i));
 166         i->shmmax = oldi->shmmax;
 167         i->shmmin = oldi->shmmin;
 168         i->shmmni = oldi->shmmni;
 169         i->shmseg = oldi->shmseg;
 170         i->shmall = oldi->shmall;
 171       }
 172 # endif
 173     return result;
 174   }
 175 #endif
 176 }
 177
 178 versioned_symbol (libc, __new_shmctl, shmctl, GLIBC_2_2);