sysdeps/unix/sysv/linux/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 <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 __old_shmctl (int shmid, int cmd, struct __old_shmid_ds *buf)
  66 {
  67   return INLINE_SYSCALL (ipc, 5, IPCOP_shmctl, shmid,
  68                          cmd, 0, CHECK_1_NULL_OK (buf));
  69 }
  70 compat_symbol (libc, __old_shmctl, shmctl, GLIBC_2_0);
  71 #endif
  72
  73 int
  74 __new_shmctl (int shmid, int cmd, struct shmid_ds *buf)
  75 {
  76 #if __ASSUME_IPC64 > 0
  77   return INLINE_SYSCALL (ipc, 5, IPCOP_shmctl, shmid, cmd | __IPC_64, 0, CHECK_1 (buf));
  78 #else
  79   switch (cmd) {
  80     case SHM_STAT:
  81     case IPC_STAT:
  82     case IPC_SET:
  83 #if __WORDSIZE != 32
  84     case IPC_INFO:
  85 #endif
  86       break;
  87     default:
  88       return INLINE_SYSCALL (ipc, 5, IPCOP_shmctl, shmid, cmd, 0, CHECK_1 (buf));
  89   }
  90
  91   {
  92     int save_errno = errno, result;
  93     struct __old_shmid_ds old;
  94
  95     /* Unfortunately there is no way how to find out for sure whether
  96        we should use old or new shmctl.  */
  97     result = INLINE_SYSCALL (ipc, 5, IPCOP_shmctl, shmid, cmd | __IPC_64, 0, CHECK_1 (buf));
  98     if (result != -1 || errno != EINVAL)
  99       return result;
 100
 101     __set_errno(save_errno);
 102     if (cmd == IPC_SET)
 103       {
 104         old.shm_perm.uid = buf->shm_perm.uid;
 105         old.shm_perm.gid = buf->shm_perm.gid;
 106         old.shm_perm.mode = buf->shm_perm.mode;
 107         if (old.shm_perm.uid != buf->shm_perm.uid ||
 108             old.shm_perm.gid != buf->shm_perm.gid)
 109           {
 110             __set_errno (EINVAL);
 111             return -1;
 112           }
 113       }
 114     result = INLINE_SYSCALL (ipc, 5, IPCOP_shmctl, shmid, cmd, 0, __ptrvalue (&old));
 115     if (result != -1 && (cmd == SHM_STAT || cmd == IPC_STAT))
 116       {
 117         memset(buf, 0, sizeof(*buf));
 118         buf->shm_perm.__key = old.shm_perm.__key;
 119         buf->shm_perm.uid = old.shm_perm.uid;
 120         buf->shm_perm.gid = old.shm_perm.gid;
 121         buf->shm_perm.cuid = old.shm_perm.cuid;
 122         buf->shm_perm.cgid = old.shm_perm.cgid;
 123         buf->shm_perm.mode = old.shm_perm.mode;
 124         buf->shm_perm.__seq = old.shm_perm.__seq;
 125         buf->shm_atime = old.shm_atime;
 126         buf->shm_dtime = old.shm_dtime;
 127         buf->shm_ctime = old.shm_ctime;
 128         buf->shm_segsz = old.shm_segsz;
 129         buf->shm_nattch = old.shm_nattch;
 130         buf->shm_cpid = old.shm_cpid;
 131         buf->shm_lpid = old.shm_lpid;
 132       }
 133 #if __WORDSIZE != 32
 134     else if (result != -1 && cmd == IPC_INFO)
 135       {
 136         struct __old_shminfo *oldi = (struct __old_shminfo *)&old;
 137         struct shminfo *i = (struct shminfo *)buf;
 138
 139         memset(i, 0, sizeof(*i));
 140         i->shmmax = oldi->shmmax;
 141         i->shmmin = oldi->shmmin;
 142         i->shmmni = oldi->shmmni;
 143         i->shmseg = oldi->shmseg;
 144         i->shmall = oldi->shmall;
 145       }
 146 #endif
 147     return result;
 148   }
 149 #endif
 150 }
 151
 152 versioned_symbol (libc, __new_shmctl, shmctl, GLIBC_2_2);