sysdeps/unix/sysv/linux/shmctl.c

   1 /* Copyright (C) 1995,1997,1998,2000,2003,2004,2006
   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, see
  18    <http://www.gnu.org/licenses/>.  */
  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 <shlib-compat.h>
  29 #include <bp-checks.h>
  30
  31 #include <kernel-features.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 /* Provide operations to control over shared memory segments.  */
  58 #if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_2)
  59 int __old_shmctl (int, int, struct __old_shmid_ds *);
  60 #endif
  61 int __new_shmctl (int, int, struct shmid_ds *);
  62
  63 #if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_2)
  64 int
  65 attribute_compat_text_section
  66 __old_shmctl (int shmid, int cmd, struct __old_shmid_ds *buf)
  67 {
  68   return INLINE_SYSCALL (ipc, 5, IPCOP_shmctl, shmid,
  69                          cmd, 0, CHECK_1_NULL_OK (buf));
  70 }
  71 compat_symbol (libc, __old_shmctl, shmctl, GLIBC_2_0);
  72 #endif
  73
  74 int
  75 __new_shmctl (int shmid, int cmd, struct shmid_ds *buf)
  76 {
  77 #if __ASSUME_IPC64 > 0
  78   return INLINE_SYSCALL (ipc, 5, IPCOP_shmctl, shmid, cmd | __IPC_64, 0,
  79                          CHECK_1 (buf));
  80 #else
  81   switch (cmd) {
  82     case SHM_STAT:
  83     case IPC_STAT:
  84     case IPC_SET:
  85 #if __WORDSIZE != 32
  86     case IPC_INFO:
  87 #endif
  88       break;
  89     default:
  90       return INLINE_SYSCALL (ipc, 5, IPCOP_shmctl, shmid, cmd, 0,
  91                              CHECK_1 (buf));
  92   }
  93
  94   {
  95     int save_errno = errno, result;
  96     union
  97       {
  98         struct __old_shmid_ds ds;
  99         struct __old_shminfo info;
 100       } old;
 101
 102     /* Unfortunately there is no way how to find out for sure whether
 103        we should use old or new shmctl.  */
 104     result = INLINE_SYSCALL (ipc, 5, IPCOP_shmctl, shmid, cmd | __IPC_64, 0,
 105                              CHECK_1 (buf));
 106     if (result != -1 || errno != EINVAL)
 107       return result;
 108
 109     __set_errno(save_errno);
 110     if (cmd == IPC_SET)
 111       {
 112         old.ds.shm_perm.uid = buf->shm_perm.uid;
 113         old.ds.shm_perm.gid = buf->shm_perm.gid;
 114         old.ds.shm_perm.mode = buf->shm_perm.mode;
 115         if (old.ds.shm_perm.uid != buf->shm_perm.uid ||
 116             old.ds.shm_perm.gid != buf->shm_perm.gid)
 117           {
 118             __set_errno (EINVAL);
 119             return -1;
 120           }
 121       }
 122     result = INLINE_SYSCALL (ipc, 5, IPCOP_shmctl, shmid, cmd, 0,
 123                              __ptrvalue (&old.ds));
 124     if (result != -1 && (cmd == SHM_STAT || cmd == IPC_STAT))
 125       {
 126         memset(buf, 0, sizeof(*buf));
 127         buf->shm_perm.__key = old.ds.shm_perm.__key;
 128         buf->shm_perm.uid = old.ds.shm_perm.uid;
 129         buf->shm_perm.gid = old.ds.shm_perm.gid;
 130         buf->shm_perm.cuid = old.ds.shm_perm.cuid;
 131         buf->shm_perm.cgid = old.ds.shm_perm.cgid;
 132         buf->shm_perm.mode = old.ds.shm_perm.mode;
 133         buf->shm_perm.__seq = old.ds.shm_perm.__seq;
 134         buf->shm_atime = old.ds.shm_atime;
 135         buf->shm_dtime = old.ds.shm_dtime;
 136         buf->shm_ctime = old.ds.shm_ctime;
 137         buf->shm_segsz = old.ds.shm_segsz;
 138         buf->shm_nattch = old.ds.shm_nattch;
 139         buf->shm_cpid = old.ds.shm_cpid;
 140         buf->shm_lpid = old.ds.shm_lpid;
 141       }
 142 #if __WORDSIZE != 32
 143     else if (result != -1 && cmd == IPC_INFO)
 144       {
 145         struct shminfo *i = (struct shminfo *)buf;
 146
 147         memset(i, 0, sizeof(*i));
 148         i->shmmax = old.info.shmmax;
 149         i->shmmin = old.info.shmmin;
 150         i->shmmni = old.info.shmmni;
 151         i->shmseg = old.info.shmseg;
 152         i->shmall = old.info.shmall;
 153       }
 154 #endif
 155     return result;
 156   }
 157 #endif
 158 }
 159
 160 versioned_symbol (libc, __new_shmctl, shmctl, GLIBC_2_2);