sysdeps/unix/sysv/linux/i386/semctl.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, 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 <stdarg.h>
  23 #include <sys/sem.h>
  24 #include <ipc_priv.h>
  25
  26 #include <sysdep.h>
  27 #include <string.h>
  28 #include <sys/syscall.h>
  29
  30 #include <kernel-features.h>
  31 #include <shlib-compat.h>
  32
  33 struct __old_semid_ds
  34 {
  35   struct __old_ipc_perm sem_perm;       /* operation permission struct */
  36   __time_t sem_otime;                   /* last semop() time */
  37   __time_t sem_ctime;                   /* last time changed by semctl() */
  38   struct sem *__sembase;                /* ptr to first semaphore in array */
  39   struct sem_queue *__sem_pending;      /* pending operations */
  40   struct sem_queue *__sem_pending_last; /* last pending operation */
  41   struct sem_undo *__undo;              /* ondo requests on this array */
  42   unsigned short int sem_nsems;         /* number of semaphores in set */
  43 };
  44
  45 /* Define a `union semun' suitable for Linux here.  */
  46 union semun
  47 {
  48   int val;                      /* value for SETVAL */
  49   struct semid_ds *buf;         /* buffer for IPC_STAT & IPC_SET */
  50   unsigned short int *array;    /* array for GETALL & SETALL */
  51   struct seminfo *__buf;        /* buffer for IPC_INFO */
  52   struct __old_semid_ds *__old_buf;
  53 };
  54
  55 #include <bp-checks.h>
  56 #include <bp-semctl.h>          /* definition of CHECK_SEMCTL needs union semum */
  57
  58 #ifdef __NR_getuid32
  59 # if __ASSUME_32BITUIDS == 0
  60 /* This variable is shared with all files that need to check for 32bit
  61    uids.  */
  62 extern int __libc_missing_32bit_uids;
  63 # endif
  64 #endif
  65
  66 /* Return identifier for array of NSEMS semaphores associated with
  67    KEY.  */
  68 #if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_2)
  69 int __old_semctl (int semid, int semnum, int cmd, ...);
  70 #endif
  71 int __new_semctl (int semid, int semnum, int cmd, ...);
  72
  73 #if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_2)
  74 int
  75 attribute_compat_text_section
  76 __old_semctl (int semid, int semnum, int cmd, ...)
  77 {
  78   union semun arg;
  79   va_list ap;
  80
  81   va_start (ap, cmd);
  82
  83   /* Get the argument.  */
  84   arg = va_arg (ap, union semun);
  85
  86   va_end (ap);
  87
  88   return INLINE_SYSCALL (ipc, 5, IPCOP_semctl, semid, semnum, cmd,
  89                          CHECK_SEMCTL (&arg, semid, cmd));
  90 }
  91 compat_symbol (libc, __old_semctl, semctl, GLIBC_2_0);
  92 #endif
  93
  94 int
  95 __new_semctl (int semid, int semnum, int cmd, ...)
  96 {
  97   union semun arg;
  98   va_list ap;
  99
 100   va_start (ap, cmd);
 101
 102   /* Get the argument.  */
 103   arg = va_arg (ap, union semun);
 104
 105   va_end (ap);
 106
 107 #if __ASSUME_32BITUIDS > 0
 108   return INLINE_SYSCALL (ipc, 5, IPCOP_semctl, semid, semnum, cmd | __IPC_64,
 109                          CHECK_SEMCTL (&arg, semid, cmd | __IPC_64));
 110 #else
 111   switch (cmd) {
 112     case SEM_STAT:
 113     case IPC_STAT:
 114     case IPC_SET:
 115       break;
 116     default:
 117       return INLINE_SYSCALL (ipc, 5, IPCOP_semctl, semid, semnum, cmd,
 118                              CHECK_SEMCTL (&arg, semid, cmd));
 119   }
 120
 121   {
 122     int result;
 123     struct __old_semid_ds old;
 124     struct semid_ds *buf;
 125
 126 #ifdef __NR_getuid32
 127     if (__libc_missing_32bit_uids <= 0)
 128       {
 129         if (__libc_missing_32bit_uids < 0)
 130           {
 131             int save_errno = errno;
 132
 133             /* Test presence of new IPC by testing for getuid32 syscall.  */
 134             result = INLINE_SYSCALL (getuid32, 0);
 135             if (result == -1 && errno == ENOSYS)
 136               __libc_missing_32bit_uids = 1;
 137             else
 138               __libc_missing_32bit_uids = 0;
 139             __set_errno(save_errno);
 140           }
 141         if (__libc_missing_32bit_uids <= 0)
 142           {
 143             result = INLINE_SYSCALL (ipc, 5, IPCOP_semctl, semid, semnum, cmd | __IPC_64,
 144                                      CHECK_SEMCTL (&arg, semid, cmd | __IPC_64));
 145             return result;
 146           }
 147       }
 148 #endif
 149
 150     buf = arg.buf;
 151     arg.__old_buf = &old;
 152     if (cmd == IPC_SET)
 153       {
 154         old.sem_perm.uid = buf->sem_perm.uid;
 155         old.sem_perm.gid = buf->sem_perm.gid;
 156         old.sem_perm.mode = buf->sem_perm.mode;
 157         if (old.sem_perm.uid != buf->sem_perm.uid ||
 158             old.sem_perm.gid != buf->sem_perm.gid)
 159           {
 160             __set_errno (EINVAL);
 161             return -1;
 162           }
 163       }
 164     result = INLINE_SYSCALL (ipc, 5, IPCOP_semctl, semid, semnum, cmd,
 165                              CHECK_SEMCTL (&arg, semid, cmd));
 166     if (result != -1 && cmd != IPC_SET)
 167       {
 168         memset(buf, 0, sizeof(*buf));
 169         buf->sem_perm.__key = old.sem_perm.__key;
 170         buf->sem_perm.uid = old.sem_perm.uid;
 171         buf->sem_perm.gid = old.sem_perm.gid;
 172         buf->sem_perm.cuid = old.sem_perm.cuid;
 173         buf->sem_perm.cgid = old.sem_perm.cgid;
 174         buf->sem_perm.mode = old.sem_perm.mode;
 175         buf->sem_perm.__seq = old.sem_perm.__seq;
 176         buf->sem_otime = old.sem_otime;
 177         buf->sem_ctime = old.sem_ctime;
 178         buf->sem_nsems = old.sem_nsems;
 179       }
 180     return result;
 181   }
 182 #endif
 183 }
 184
 185 versioned_symbol (libc, __new_semctl, semctl, GLIBC_2_2);