sysdeps/unix/sysv/linux/i386/semctl.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 Library General Public License as
   7    published by the Free Software Foundation; either version 2 of the
   8    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    Library General Public License for more details.
  14
  15    You should have received a copy of the GNU Library General Public
  16    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  17    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  18    Boston, MA 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 };
  52
  53 #ifdef __NR_getuid32
  54 # if __ASSUME_32BITUIDS == 0
  55 /* This variable is shared with all files that need to check for 32bit
  56    uids.  */
  57 extern int __libc_missing_32bit_uids;
  58 # endif
  59 #endif
  60
  61 /* Return identifier for array of NSEMS semaphores associated with
  62    KEY.  */
  63 #if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_2)
  64 int __old_semctl (int semid, int semnum, int cmd, ...);
  65 #endif
  66 int __new_semctl (int semid, int semnum, int cmd, ...);
  67
  68 #if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_2)
  69 int
  70 __old_semctl (int semid, int semnum, int cmd, ...)
  71 {
  72   union semun arg;
  73   va_list ap;
  74
  75   va_start (ap, cmd);
  76
  77   /* Get the argument.  */
  78   arg = va_arg (ap, union semun);
  79
  80   va_end (ap);
  81
  82   return INLINE_SYSCALL (ipc, 5, IPCOP_semctl, semid, semnum, cmd, &arg);
  83 }
  84 compat_symbol (libc, __old_semctl, semctl, GLIBC_2_0);
  85 #endif
  86
  87 int
  88 __new_semctl (int semid, int semnum, int cmd, ...)
  89 {
  90   union semun arg;
  91   va_list ap;
  92
  93   va_start (ap, cmd);
  94
  95   /* Get the argument.  */
  96   arg = va_arg (ap, union semun);
  97
  98   va_end (ap);
  99
 100 #if __ASSUME_32BITUIDS > 0
 101   return INLINE_SYSCALL (ipc, 5, IPCOP_semctl, semid, semnum, cmd | __IPC_64, &arg);
 102 #else
 103   switch (cmd) {
 104     case SEM_STAT:
 105     case IPC_STAT:
 106     case IPC_SET:
 107       break;
 108     default:
 109       return INLINE_SYSCALL (ipc, 5, IPCOP_semctl, semid, semnum, cmd, &arg);
 110   }
 111
 112   {
 113     int result;
 114     struct __old_semid_ds old;
 115     struct semid_ds *buf;
 116
 117 #ifdef __NR_getuid32
 118     if (__libc_missing_32bit_uids <= 0)
 119       {
 120         if (__libc_missing_32bit_uids < 0)
 121           {
 122             int save_errno = errno;
 123
 124             /* Test presence of new IPC by testing for getuid32 syscall.  */
 125             result = INLINE_SYSCALL (getuid32, 0);
 126             if (result == -1 && errno == ENOSYS)
 127               __libc_missing_32bit_uids = 1;
 128             else
 129               __libc_missing_32bit_uids = 0;
 130             __set_errno(save_errno);
 131           }
 132         if (__libc_missing_32bit_uids <= 0)
 133           {
 134             result = INLINE_SYSCALL (ipc, 5, IPCOP_semctl, semid, semnum, cmd | __IPC_64, &arg);
 135             return result;
 136           }
 137       }
 138 #endif
 139
 140     buf = arg.buf;
 141     arg.buf = (struct semid_ds *)&old;
 142     if (cmd == IPC_SET)
 143       {
 144         old.sem_perm.uid = buf->sem_perm.uid;
 145         old.sem_perm.gid = buf->sem_perm.gid;
 146         old.sem_perm.mode = buf->sem_perm.mode;
 147         if (old.sem_perm.uid != buf->sem_perm.uid ||
 148             old.sem_perm.gid != buf->sem_perm.gid)
 149           {
 150             __set_errno (EINVAL);
 151             return -1;
 152           }
 153       }
 154     result = INLINE_SYSCALL (ipc, 5, IPCOP_semctl, semid, semnum, cmd, &arg);
 155     if (result != -1 && cmd != IPC_SET)
 156       {
 157         memset(buf, 0, sizeof(*buf));
 158         buf->sem_perm.__key = old.sem_perm.__key;
 159         buf->sem_perm.uid = old.sem_perm.uid;
 160         buf->sem_perm.gid = old.sem_perm.gid;
 161         buf->sem_perm.cuid = old.sem_perm.cuid;
 162         buf->sem_perm.cgid = old.sem_perm.cgid;
 163         buf->sem_perm.mode = old.sem_perm.mode;
 164         buf->sem_perm.__seq = old.sem_perm.__seq;
 165         buf->sem_otime = old.sem_otime;
 166         buf->sem_ctime = old.sem_ctime;
 167         buf->sem_nsems = old.sem_nsems;
 168       }
 169     return result;
 170   }
 171 #endif
 172 }
 173
 174 versioned_symbol (libc, __new_semctl, semctl, GLIBC_2_2);