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 Library General Public License as
   7    published by the Free Software Foundation; either version 2 of the
   8    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    Library General Public License for more details.
  14
  15    You should have received a copy of the GNU Library General Public
  16    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  17    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  18    Boston, MA 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
  29 #include "kernel-features.h"
  30 #include <shlib-compat.h>
  31
  32 struct __old_shmid_ds
  33 {
  34   struct __old_ipc_perm shm_perm;       /* operation permission struct */
  35   int shm_segsz;                        /* size of segment in bytes */
  36   __time_t shm_atime;                   /* time of last shmat() */
  37   __time_t shm_dtime;                   /* time of last shmdt() */
  38   __time_t shm_ctime;                   /* time of last change by shmctl() */
  39   __ipc_pid_t shm_cpid;                 /* pid of creator */
  40   __ipc_pid_t shm_lpid;                 /* pid of last shmop */
  41   unsigned short int shm_nattch;        /* number of current attaches */
  42   unsigned short int __shm_npages;      /* size of segment (pages) */
  43   unsigned long int *__shm_pages;       /* array of ptrs to frames -> SHMMAX */
  44   struct vm_area_struct *__attaches;    /* descriptors for attaches */
  45 };
  46
  47 struct __old_shminfo
  48 {
  49   int shmmax;
  50   int shmmin;
  51   int shmmni;
  52   int shmseg;
  53   int shmall;
  54 };
  55
  56 #ifdef __NR_getuid32
  57 # if __ASSUME_32BITUIDS == 0
  58 /* This variable is shared with all files that need to check for 32bit
  59    uids.  */
  60 extern int __libc_missing_32bit_uids;
  61 # endif
  62 #endif
  63
  64 /* Provide operations to control over shared memory segments.  */
  65 #if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_2)
  66 int __old_shmctl (int, int, struct __old_shmid_ds *);
  67 #endif
  68 int __new_shmctl (int, int, struct shmid_ds *);
  69
  70 #if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_2)
  71 int
  72 __old_shmctl (int shmid, int cmd, struct __old_shmid_ds *buf)
  73 {
  74   return INLINE_SYSCALL (ipc, 5, IPCOP_shmctl, shmid, cmd, 0, buf);
  75 }
  76 compat_symbol (libc, __old_shmctl, shmctl, GLIBC_2_0);
  77 #endif
  78
  79 int
  80 __new_shmctl (int shmid, int cmd, struct shmid_ds *buf)
  81 {
  82 #if __ASSUME_32BITUIDS > 0
  83   return INLINE_SYSCALL (ipc, 5, IPCOP_shmctl, shmid, cmd | __IPC_64, 0, buf);
  84 #else
  85   switch (cmd) {
  86     case SHM_STAT:
  87     case IPC_STAT:
  88     case IPC_SET:
  89 # if __WORDSIZE != 32
  90     case IPC_INFO:
  91 # endif
  92       break;
  93     default:
  94       return INLINE_SYSCALL (ipc, 5, IPCOP_shmctl, shmid, cmd, 0, buf);
  95   }
  96
  97   {
  98     struct __old_shmid_ds old;
  99     int result;
 100
 101 # ifdef __NR_getuid32
 102     if (__libc_missing_32bit_uids <= 0)
 103       {
 104         if (__libc_missing_32bit_uids < 0)
 105           {
 106             int save_errno = errno;
 107
 108             /* Test presence of new IPC by testing for getuid32 syscall.  */
 109             result = INLINE_SYSCALL (getuid32, 0);
 110             if (result == -1 && errno == ENOSYS)
 111               __libc_missing_32bit_uids = 1;
 112             else
 113               __libc_missing_32bit_uids = 0;
 114             __set_errno(save_errno);
 115           }
 116         if (__libc_missing_32bit_uids <= 0)
 117           return INLINE_SYSCALL (ipc, 5, IPCOP_shmctl, shmid, cmd | __IPC_64,
 118                                  0, buf);
 119       }
 120 # endif
 121
 122     if (cmd == IPC_SET)
 123       {
 124         old.shm_perm.uid = buf->shm_perm.uid;
 125         old.shm_perm.gid = buf->shm_perm.gid;
 126         old.shm_perm.mode = buf->shm_perm.mode;
 127         if (old.shm_perm.uid != buf->shm_perm.uid ||
 128             old.shm_perm.gid != buf->shm_perm.gid)
 129           {
 130             __set_errno (EINVAL);
 131             return -1;
 132           }
 133       }
 134     result = INLINE_SYSCALL (ipc, 5, IPCOP_shmctl, shmid, cmd, 0, &old);
 135     if (result != -1 && (cmd == SHM_STAT || cmd == IPC_STAT))
 136       {
 137         memset(buf, 0, sizeof(*buf));
 138         buf->shm_perm.__key = old.shm_perm.__key;
 139         buf->shm_perm.uid = old.shm_perm.uid;
 140         buf->shm_perm.gid = old.shm_perm.gid;
 141         buf->shm_perm.cuid = old.shm_perm.cuid;
 142         buf->shm_perm.cgid = old.shm_perm.cgid;
 143         buf->shm_perm.mode = old.shm_perm.mode;
 144         buf->shm_perm.__seq = old.shm_perm.__seq;
 145         buf->shm_atime = old.shm_atime;
 146         buf->shm_dtime = old.shm_dtime;
 147         buf->shm_ctime = old.shm_ctime;
 148         buf->shm_segsz = old.shm_segsz;
 149         buf->shm_nattch = old.shm_nattch;
 150         buf->shm_cpid = old.shm_cpid;
 151         buf->shm_lpid = old.shm_lpid;
 152       }
 153 # if __WORDSIZE != 32
 154     else if (result != -1 && cmd == IPC_INFO)
 155       {
 156         struct __old_shminfo *oldi = (struct __old_shminfo *)&old;
 157         struct shminfo *i = (struct shminfo *)buf;
 158
 159         memset(i, 0, sizeof(*i));
 160         i->shmmax = oldi->shmmax;
 161         i->shmmin = oldi->shmmin;
 162         i->shmmni = oldi->shmmni;
 163         i->shmseg = oldi->shmseg;
 164         i->shmall = oldi->shmall;
 165       }
 166 # endif
 167     return result;
 168   }
 169 #endif
 170 }
 171
 172 versioned_symbol (libc, __new_shmctl, shmctl, GLIBC_2_2);