sysdeps/unix/sysv/linux/alpha/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
  31 struct __old_semid_ds
  32 {
  33   struct __old_ipc_perm sem_perm;       /* operation permission struct */
  34   __time_t sem_otime;                   /* last semop() time */
  35   __time_t sem_ctime;                   /* last time changed by semctl() */
  36   struct sem *__sembase;                /* ptr to first semaphore in array */
  37   struct sem_queue *__sem_pending;      /* pending operations */
  38   struct sem_queue *__sem_pending_last; /* last pending operation */
  39   struct sem_undo *__undo;              /* ondo requests on this array */
  40   unsigned short int sem_nsems;         /* number of semaphores in set */
  41 };
  42
  43 /* Define a `union semun' suitable for Linux here.  */
  44 union semun
  45 {
  46   int val;                      /* value for SETVAL */
  47   struct semid_ds *buf;         /* buffer for IPC_STAT & IPC_SET */
  48   unsigned short int *array;    /* array for GETALL & SETALL */
  49   struct seminfo *__buf;        /* buffer for IPC_INFO */
  50 };
  51
  52 #include <bp-checks.h>
  53 #include <bp-semctl.h>          /* definition of CHECK_SEMCTL needs union semum */
  54
  55 /* Return identifier for array of NSEMS semaphores associated with
  56    KEY.  */
  57 int __new_semctl (int semid, int semnum, int cmd, ...);
  58
  59 int
  60 __new_semctl (int semid, int semnum, int cmd, ...)
  61 {
  62   union semun arg;
  63   va_list ap;
  64
  65   va_start (ap, cmd);
  66
  67   /* Get the argument.  */
  68   arg = va_arg (ap, union semun);
  69
  70   va_end (ap);
  71
  72 #if __ASSUME_32BITUIDS > 0
  73   return INLINE_SYSCALL (semctl, 4, semid, semnum, cmd | __IPC_64,
  74                          CHECK_SEMCTL (&arg, semid, cmd | __IPC_64)->array);
  75 #else
  76   switch (cmd) {
  77     case SEM_STAT:
  78     case IPC_STAT:
  79     case IPC_SET:
  80       break;
  81     default:
  82       return INLINE_SYSCALL (semctl, 4, semid, semnum, cmd,
  83                              CHECK_SEMCTL (&arg, semid, cmd)->array);
  84   }
  85
  86   {
  87     int save_errno = errno, result;
  88     struct __old_semid_ds old;
  89     struct semid_ds *buf;
  90
  91     /* Unfortunately there is no way how to find out for sure whether
  92        we should use old or new semctl.  */
  93     result = INLINE_SYSCALL (semctl, 4, semid, semnum, cmd | __IPC_64,
  94                              CHECK_SEMCTL (&arg, semid, cmd | __IPC_64)->array);
  95     if (result != -1 || errno != EINVAL)
  96       return result;
  97
  98     __set_errno(save_errno);
  99     buf = arg.buf;
 100     arg.buf = (void *)&old;
 101     if (cmd == IPC_SET)
 102       {
 103         old.sem_perm.uid = buf->sem_perm.uid;
 104         old.sem_perm.gid = buf->sem_perm.gid;
 105         old.sem_perm.mode = buf->sem_perm.mode;
 106         if (old.sem_perm.uid != buf->sem_perm.uid ||
 107             old.sem_perm.gid != buf->sem_perm.gid)
 108           {
 109             __set_errno (EINVAL);
 110             return -1;
 111           }
 112       }
 113     result = INLINE_SYSCALL (semctl, 4, semid, semnum, cmd,
 114                              CHECK_SEMCTL (&arg, semid, cmd)->array);
 115     if (result != -1 && cmd != IPC_SET)
 116       {
 117         memset(buf, 0, sizeof(*buf));
 118         buf->sem_perm.__key = old.sem_perm.__key;
 119         buf->sem_perm.uid = old.sem_perm.uid;
 120         buf->sem_perm.gid = old.sem_perm.gid;
 121         buf->sem_perm.cuid = old.sem_perm.cuid;
 122         buf->sem_perm.cgid = old.sem_perm.cgid;
 123         buf->sem_perm.mode = old.sem_perm.mode;
 124         buf->sem_perm.__seq = old.sem_perm.__seq;
 125         buf->sem_otime = old.sem_otime;
 126         buf->sem_ctime = old.sem_ctime;
 127         buf->sem_nsems = old.sem_nsems;
 128       }
 129     return result;
 130   }
 131 #endif
 132 }
 133
 134 #include <shlib-compat.h>
 135 versioned_symbol (libc, __new_semctl, semctl, GLIBC_2_2);