sysdeps/unix/sysv/linux/shmctl.c

   1 /* Copyright (C) 1995, 1997, 1998, 2000, 2003, 2004
   2    Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Ulrich Drepper <drepper@gnu.ai.mit.edu>, August 1995.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, write to the Free
  18    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  19    02111-1307 USA.  */
  20
  21 #include <errno.h>
  22 #include <sys/shm.h>
  23 #include <ipc_priv.h>
  24
  25 #include <sysdep.h>
  26 #include <string.h>
  27 #include <sys/syscall.h>
  28 #include <bits/wordsize.h>
  29 #include <shlib-compat.h>
  30 #include <bp-checks.h>
  31
  32 #include "kernel-features.h"
  33
  34 struct __old_shmid_ds
  35 {
  36   struct __old_ipc_perm shm_perm;       /* operation permission struct */
  37   int shm_segsz;                        /* size of segment in bytes */
  38   __time_t shm_atime;                   /* time of last shmat() */
  39   __time_t shm_dtime;                   /* time of last shmdt() */
  40   __time_t shm_ctime;                   /* time of last change by shmctl() */
  41   __ipc_pid_t shm_cpid;                 /* pid of creator */
  42   __ipc_pid_t shm_lpid;                 /* pid of last shmop */
  43   unsigned short int shm_nattch;        /* number of current attaches */
  44   unsigned short int __shm_npages;      /* size of segment (pages) */
  45   unsigned long int *__unbounded __shm_pages; /* array of ptrs to frames -> SHMMAX */
  46   struct vm_area_struct *__unbounded __attaches; /* descriptors for attaches */
  47 };
  48
  49 struct __old_shminfo
  50 {
  51   int shmmax;
  52   int shmmin;
  53   int shmmni;
  54   int shmseg;
  55   int shmall;
  56 };
  57
  58 /* Provide operations to control over shared memory segments.  */
  59 #if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_2)
  60 int __old_shmctl (int, int, struct __old_shmid_ds *);
  61 #endif
  62 int __new_shmctl (int, int, struct shmid_ds *);
  63
  64 #if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_2)
  65 int
  66 attribute_compat_text_section
  67 __old_shmctl (int shmid, int cmd, struct __old_shmid_ds *buf)
  68 {
  69   return INLINE_SYSCALL (ipc, 5, IPCOP_shmctl, shmid,
  70                          cmd, 0, CHECK_1_NULL_OK (buf));
  71 }
  72 compat_symbol (libc, __old_shmctl, shmctl, GLIBC_2_0);
  73 #endif
  74
  75 int
  76 __new_shmctl (int shmid, int cmd, struct shmid_ds *buf)
  77 {
  78 #if __ASSUME_IPC64 > 0
  79   return INLINE_SYSCALL (ipc, 5, IPCOP_shmctl, shmid, cmd | __IPC_64, 0,
  80                          CHECK_1 (buf));
  81 #else
  82   switch (cmd) {
  83     case SHM_STAT:
  84     case IPC_STAT:
  85     case IPC_SET:
  86 #if __WORDSIZE != 32
  87     case IPC_INFO:
  88 #endif
  89       break;
  90     default:
  91       return INLINE_SYSCALL (ipc, 5, IPCOP_shmctl, shmid, cmd, 0,
  92                              CHECK_1 (buf));
  93   }
  94
  95   {
  96     int save_errno = errno, result;
  97     union
  98       {
  99         struct __old_shmid_ds ds;
 100         struct __old_shminfo info;
 101       } old;
 102
 103     /* Unfortunately there is no way how to find out for sure whether
 104        we should use old or new shmctl.  */
 105     result = INLINE_SYSCALL (ipc, 5, IPCOP_shmctl, shmid, cmd | __IPC_64, 0,
 106                              CHECK_1 (buf));
 107     if (result != -1 || errno != EINVAL)
 108       return result;
 109
 110     __set_errno(save_errno);
 111     if (cmd == IPC_SET)
 112       {
 113         old.ds.shm_perm.uid = buf->shm_perm.uid;
 114         old.ds.shm_perm.gid = buf->shm_perm.gid;
 115         old.ds.shm_perm.mode = buf->shm_perm.mode;
 116         if (old.ds.shm_perm.uid != buf->shm_perm.uid ||
 117             old.ds.shm_perm.gid != buf->shm_perm.gid)
 118           {
 119             __set_errno (EINVAL);
 120             return -1;
 121           }
 122       }
 123     result = INLINE_SYSCALL (ipc, 5, IPCOP_shmctl, shmid, cmd, 0,
 124                              __ptrvalue (&old.ds));
 125     if (result != -1 && (cmd == SHM_STAT || cmd == IPC_STAT))
 126       {
 127         memset(buf, 0, sizeof(*buf));
 128         buf->shm_perm.__key = old.ds.shm_perm.__key;
 129         buf->shm_perm.uid = old.ds.shm_perm.uid;
 130         buf->shm_perm.gid = old.ds.shm_perm.gid;
 131         buf->shm_perm.cuid = old.ds.shm_perm.cuid;
 132         buf->shm_perm.cgid = old.ds.shm_perm.cgid;
 133         buf->shm_perm.mode = old.ds.shm_perm.mode;
 134         buf->shm_perm.__seq = old.ds.shm_perm.__seq;
 135         buf->shm_atime = old.ds.shm_atime;
 136         buf->shm_dtime = old.ds.shm_dtime;
 137         buf->shm_ctime = old.ds.shm_ctime;
 138         buf->shm_segsz = old.ds.shm_segsz;
 139         buf->shm_nattch = old.ds.shm_nattch;
 140         buf->shm_cpid = old.ds.shm_cpid;
 141         buf->shm_lpid = old.ds.shm_lpid;
 142       }
 143 #if __WORDSIZE != 32
 144     else if (result != -1 && cmd == IPC_INFO)
 145       {
 146         struct shminfo *i = (struct shminfo *)buf;
 147
 148         memset(i, 0, sizeof(*i));
 149         i->shmmax = old.info.shmmax;
 150         i->shmmin = old.info.shmmin;
 151         i->shmmni = old.info.shmmni;
 152         i->shmseg = old.info.shmseg;
 153         i->shmall = old.info.shmall;
 154       }
 155 #endif
 156     return result;
 157   }
 158 #endif
 159 }
 160
 161 versioned_symbol (libc, __new_shmctl, shmctl, GLIBC_2_2);