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

   1 /* Copyright (C) 1995, 1997, 1998, 2000, 2003 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 <stdarg.h>
  22 #include <sys/sem.h>
  23 #include <ipc_priv.h>
  24
  25 #include <sysdep.h>
  26 #include <string.h>
  27 #include <sys/syscall.h>
  28
  29 #include "kernel-features.h"
  30 #include <shlib-compat.h>
  31
  32 struct __old_semid_ds
  33 {
  34   struct __old_ipc_perm sem_perm;       /* operation permission struct */
  35   __time_t sem_otime;                   /* last semop() time */
  36   __time_t sem_ctime;                   /* last time changed by semctl() */
  37   struct sem *__sembase;                /* ptr to first semaphore in array */
  38   struct sem_queue *__sem_pending;      /* pending operations */
  39   struct sem_queue *__sem_pending_last; /* last pending operation */
  40   struct sem_undo *__undo;              /* ondo requests on this array */
  41   unsigned short int sem_nsems;         /* number of semaphores in set */
  42 };
  43
  44 /* Define a `union semun' suitable for Linux here.  */
  45 union semun
  46 {
  47   int val;                      /* value for SETVAL */
  48   struct semid_ds *buf;         /* buffer for IPC_STAT & IPC_SET */
  49   unsigned short int *array;    /* array for GETALL & SETALL */
  50   struct seminfo *__buf;        /* buffer for IPC_INFO */
  51   struct __old_semid_ds *__old_buf;
  52 };
  53
  54 #include <bp-checks.h>
  55 #include <bp-semctl.h>          /* definition of CHECK_SEMCTL needs union semum */
  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 /* Return identifier for array of NSEMS semaphores associated with
  66    KEY.  */
  67 #if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_2)
  68 int __old_semctl (int semid, int semnum, int cmd, ...);
  69 #endif
  70 int __new_semctl (int semid, int semnum, int cmd, ...);
  71
  72 #if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_2)
  73 int
  74 __old_semctl (int semid, int semnum, int cmd, ...)
  75 {
  76   union semun arg;
  77   va_list ap;
  78
  79   va_start (ap, cmd);
  80
  81   /* Get the argument.  */
  82   arg = va_arg (ap, union semun);
  83
  84   va_end (ap);
  85
  86   return INLINE_SYSCALL (ipc, 5, IPCOP_semctl, semid, semnum, cmd,
  87                          CHECK_SEMCTL (&arg, semid, cmd));
  88 }
  89 compat_symbol (libc, __old_semctl, semctl, GLIBC_2_0);
  90 #endif
  91
  92 int
  93 __new_semctl (int semid, int semnum, int cmd, ...)
  94 {
  95   union semun arg;
  96   va_list ap;
  97
  98   va_start (ap, cmd);
  99
 100   /* Get the argument.  */
 101   arg = va_arg (ap, union semun);
 102
 103   va_end (ap);
 104
 105 #if __ASSUME_32BITUIDS > 0
 106   return INLINE_SYSCALL (ipc, 5, IPCOP_semctl, semid, semnum, cmd | __IPC_64,
 107                          CHECK_SEMCTL (&arg, semid, cmd | __IPC_64));
 108 #else
 109   switch (cmd) {
 110     case SEM_STAT:
 111     case IPC_STAT:
 112     case IPC_SET:
 113       break;
 114     default:
 115       return INLINE_SYSCALL (ipc, 5, IPCOP_semctl, semid, semnum, cmd,
 116                              CHECK_SEMCTL (&arg, semid, cmd));
 117   }
 118
 119   {
 120     int result;
 121     struct __old_semid_ds old;
 122     struct semid_ds *buf;
 123
 124 #ifdef __NR_getuid32
 125     if (__libc_missing_32bit_uids <= 0)
 126       {
 127         if (__libc_missing_32bit_uids < 0)
 128           {
 129             int save_errno = errno;
 130
 131             /* Test presence of new IPC by testing for getuid32 syscall.  */
 132             result = INLINE_SYSCALL (getuid32, 0);
 133             if (result == -1 && errno == ENOSYS)
 134               __libc_missing_32bit_uids = 1;
 135             else
 136               __libc_missing_32bit_uids = 0;
 137             __set_errno(save_errno);
 138           }
 139         if (__libc_missing_32bit_uids <= 0)
 140           {
 141             result = INLINE_SYSCALL (ipc, 5, IPCOP_semctl, semid, semnum, cmd | __IPC_64,
 142                                      CHECK_SEMCTL (&arg, semid, cmd | __IPC_64));
 143             return result;
 144           }
 145       }
 146 #endif
 147
 148     buf = arg.buf;
 149     arg.__old_buf = &old;
 150     if (cmd == IPC_SET)
 151       {
 152         old.sem_perm.uid = buf->sem_perm.uid;
 153         old.sem_perm.gid = buf->sem_perm.gid;
 154         old.sem_perm.mode = buf->sem_perm.mode;
 155         if (old.sem_perm.uid != buf->sem_perm.uid ||
 156             old.sem_perm.gid != buf->sem_perm.gid)
 157           {
 158             __set_errno (EINVAL);
 159             return -1;
 160           }
 161       }
 162     result = INLINE_SYSCALL (ipc, 5, IPCOP_semctl, semid, semnum, cmd,
 163                              CHECK_SEMCTL (&arg, semid, cmd));
 164     if (result != -1 && cmd != IPC_SET)
 165       {
 166         memset(buf, 0, sizeof(*buf));
 167         buf->sem_perm.__key = old.sem_perm.__key;
 168         buf->sem_perm.uid = old.sem_perm.uid;
 169         buf->sem_perm.gid = old.sem_perm.gid;
 170         buf->sem_perm.cuid = old.sem_perm.cuid;
 171         buf->sem_perm.cgid = old.sem_perm.cgid;
 172         buf->sem_perm.mode = old.sem_perm.mode;
 173         buf->sem_perm.__seq = old.sem_perm.__seq;
 174         buf->sem_otime = old.sem_otime;
 175         buf->sem_ctime = old.sem_ctime;
 176         buf->sem_nsems = old.sem_nsems;
 177       }
 178     return result;
 179   }
 180 #endif
 181 }
 182
 183 versioned_symbol (libc, __new_semctl, semctl, GLIBC_2_2);