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

   1 /* Copyright (C) 1995,1997,1998,2000,2003,2004 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 attribute_compat_text_section
  75 __old_semctl (int semid, int semnum, int cmd, ...)
  76 {
  77   union semun arg;
  78   va_list ap;
  79
  80   va_start (ap, cmd);
  81
  82   /* Get the argument.  */
  83   arg = va_arg (ap, union semun);
  84
  85   va_end (ap);
  86
  87   return INLINE_SYSCALL (ipc, 5, IPCOP_semctl, semid, semnum, cmd,
  88                          CHECK_SEMCTL (&arg, semid, cmd));
  89 }
  90 compat_symbol (libc, __old_semctl, semctl, GLIBC_2_0);
  91 #endif
  92
  93 int
  94 __new_semctl (int semid, int semnum, int cmd, ...)
  95 {
  96   union semun arg;
  97   va_list ap;
  98
  99   va_start (ap, cmd);
 100
 101   /* Get the argument.  */
 102   arg = va_arg (ap, union semun);
 103
 104   va_end (ap);
 105
 106 #if __ASSUME_32BITUIDS > 0
 107   return INLINE_SYSCALL (ipc, 5, IPCOP_semctl, semid, semnum, cmd | __IPC_64,
 108                          CHECK_SEMCTL (&arg, semid, cmd | __IPC_64));
 109 #else
 110   switch (cmd) {
 111     case SEM_STAT:
 112     case IPC_STAT:
 113     case IPC_SET:
 114       break;
 115     default:
 116       return INLINE_SYSCALL (ipc, 5, IPCOP_semctl, semid, semnum, cmd,
 117                              CHECK_SEMCTL (&arg, semid, cmd));
 118   }
 119
 120   {
 121     int result;
 122     struct __old_semid_ds old;
 123     struct semid_ds *buf;
 124
 125 #ifdef __NR_getuid32
 126     if (__libc_missing_32bit_uids <= 0)
 127       {
 128         if (__libc_missing_32bit_uids < 0)
 129           {
 130             int save_errno = errno;
 131
 132             /* Test presence of new IPC by testing for getuid32 syscall.  */
 133             result = INLINE_SYSCALL (getuid32, 0);
 134             if (result == -1 && errno == ENOSYS)
 135               __libc_missing_32bit_uids = 1;
 136             else
 137               __libc_missing_32bit_uids = 0;
 138             __set_errno(save_errno);
 139           }
 140         if (__libc_missing_32bit_uids <= 0)
 141           {
 142             result = INLINE_SYSCALL (ipc, 5, IPCOP_semctl, semid, semnum, cmd | __IPC_64,
 143                                      CHECK_SEMCTL (&arg, semid, cmd | __IPC_64));
 144             return result;
 145           }
 146       }
 147 #endif
 148
 149     buf = arg.buf;
 150     arg.__old_buf = &old;
 151     if (cmd == IPC_SET)
 152       {
 153         old.sem_perm.uid = buf->sem_perm.uid;
 154         old.sem_perm.gid = buf->sem_perm.gid;
 155         old.sem_perm.mode = buf->sem_perm.mode;
 156         if (old.sem_perm.uid != buf->sem_perm.uid ||
 157             old.sem_perm.gid != buf->sem_perm.gid)
 158           {
 159             __set_errno (EINVAL);
 160             return -1;
 161           }
 162       }
 163     result = INLINE_SYSCALL (ipc, 5, IPCOP_semctl, semid, semnum, cmd,
 164                              CHECK_SEMCTL (&arg, semid, cmd));
 165     if (result != -1 && cmd != IPC_SET)
 166       {
 167         memset(buf, 0, sizeof(*buf));
 168         buf->sem_perm.__key = old.sem_perm.__key;
 169         buf->sem_perm.uid = old.sem_perm.uid;
 170         buf->sem_perm.gid = old.sem_perm.gid;
 171         buf->sem_perm.cuid = old.sem_perm.cuid;
 172         buf->sem_perm.cgid = old.sem_perm.cgid;
 173         buf->sem_perm.mode = old.sem_perm.mode;
 174         buf->sem_perm.__seq = old.sem_perm.__seq;
 175         buf->sem_otime = old.sem_otime;
 176         buf->sem_ctime = old.sem_ctime;
 177         buf->sem_nsems = old.sem_nsems;
 178       }
 179     return result;
 180   }
 181 #endif
 182 }
 183
 184 versioned_symbol (libc, __new_semctl, semctl, GLIBC_2_2);