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

   1 /* Copyright (C) 1995,1997,1998,2000,2003,2006
   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
  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 #include <bp-checks.h>
  54 #include <bp-semctl.h>          /* definition of CHECK_SEMCTL needs union semum */
  55
  56 /* Return identifier for array of NSEMS semaphores associated with
  57    KEY.  */
  58 int __new_semctl (int semid, int semnum, int cmd, ...);
  59
  60 int
  61 __new_semctl (int semid, int semnum, int cmd, ...)
  62 {
  63   union semun arg;
  64   va_list ap;
  65
  66   va_start (ap, cmd);
  67
  68   /* Get the argument.  */
  69   arg = va_arg (ap, union semun);
  70
  71   va_end (ap);
  72
  73 #if __ASSUME_32BITUIDS > 0
  74   return INLINE_SYSCALL (semctl, 4, semid, semnum, cmd | __IPC_64,
  75                          CHECK_SEMCTL (&arg, semid, cmd | __IPC_64)->array);
  76 #else
  77   switch (cmd) {
  78     case SEM_STAT:
  79     case IPC_STAT:
  80     case IPC_SET:
  81       break;
  82     default:
  83       return INLINE_SYSCALL (semctl, 4, semid, semnum, cmd,
  84                              CHECK_SEMCTL (&arg, semid, cmd)->array);
  85   }
  86
  87   {
  88     int save_errno = errno, result;
  89     struct __old_semid_ds old;
  90     struct semid_ds *buf;
  91
  92     /* Unfortunately there is no way how to find out for sure whether
  93        we should use old or new semctl.  */
  94     result = INLINE_SYSCALL (semctl, 4, semid, semnum, cmd | __IPC_64,
  95                              CHECK_SEMCTL (&arg, semid, cmd | __IPC_64)->array);
  96     if (result != -1 || errno != EINVAL)
  97       return result;
  98
  99     __set_errno(save_errno);
 100     buf = arg.buf;
 101     arg.buf = (void *)&old;
 102     if (cmd == IPC_SET)
 103       {
 104         old.sem_perm.uid = buf->sem_perm.uid;
 105         old.sem_perm.gid = buf->sem_perm.gid;
 106         old.sem_perm.mode = buf->sem_perm.mode;
 107         if (old.sem_perm.uid != buf->sem_perm.uid ||
 108             old.sem_perm.gid != buf->sem_perm.gid)
 109           {
 110             __set_errno (EINVAL);
 111             return -1;
 112           }
 113       }
 114     result = INLINE_SYSCALL (semctl, 4, semid, semnum, cmd,
 115                              CHECK_SEMCTL (&arg, semid, cmd)->array);
 116     if (result != -1 && cmd != IPC_SET)
 117       {
 118         memset(buf, 0, sizeof(*buf));
 119         buf->sem_perm.__key = old.sem_perm.__key;
 120         buf->sem_perm.uid = old.sem_perm.uid;
 121         buf->sem_perm.gid = old.sem_perm.gid;
 122         buf->sem_perm.cuid = old.sem_perm.cuid;
 123         buf->sem_perm.cgid = old.sem_perm.cgid;
 124         buf->sem_perm.mode = old.sem_perm.mode;
 125         buf->sem_perm.__seq = old.sem_perm.__seq;
 126         buf->sem_otime = old.sem_otime;
 127         buf->sem_ctime = old.sem_ctime;
 128         buf->sem_nsems = old.sem_nsems;
 129       }
 130     return result;
 131   }
 132 #endif
 133 }
 134
 135 #include <shlib-compat.h>
 136 versioned_symbol (libc, __new_semctl, semctl, GLIBC_2_2);