sysdeps/unix/sysv/linux/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 #include <shlib-compat.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
  54 /* Return identifier for array of NSEMS semaphores associated with
  55    KEY.  */
  56 #if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_2)
  57 int __old_semctl (int semid, int semnum, int cmd, ...);
  58 #endif
  59 int __new_semctl (int semid, int semnum, int cmd, ...);
  60
  61 #if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_2)
  62 int
  63 __old_semctl (int semid, int semnum, int cmd, ...)
  64 {
  65   union semun arg;
  66   va_list ap;
  67
  68   va_start (ap, cmd);
  69
  70   /* Get the argument.  */
  71   arg = va_arg (ap, union semun);
  72
  73   va_end (ap);
  74
  75   return INLINE_SYSCALL (ipc, 5, IPCOP_semctl, semid, semnum, cmd, &arg);
  76 }
  77 compat_symbol (libc, __old_semctl, semctl, GLIBC_2_0);
  78 #endif
  79
  80 int
  81 __new_semctl (int semid, int semnum, int cmd, ...)
  82 {
  83   union semun arg;
  84   va_list ap;
  85
  86   va_start (ap, cmd);
  87
  88   /* Get the argument.  */
  89   arg = va_arg (ap, union semun);
  90
  91   va_end (ap);
  92
  93 #if __ASSUME_32BITUIDS > 0
  94   return INLINE_SYSCALL (ipc, 5, IPCOP_semctl, semid, semnum, cmd | __IPC_64, &arg);
  95 #else
  96   switch (cmd) {
  97     case SEM_STAT:
  98     case IPC_STAT:
  99     case IPC_SET:
 100       break;
 101     default:
 102       return INLINE_SYSCALL (ipc, 5, IPCOP_semctl, semid, semnum, cmd, &arg);
 103   }
 104
 105   {
 106     int save_errno = errno, result;
 107     struct __old_semid_ds old;
 108     struct semid_ds *buf;
 109
 110     /* Unfortunately there is no way how to find out for sure whether
 111        we should use old or new semctl.  */
 112     result = INLINE_SYSCALL (ipc, 5, IPCOP_semctl, semid, semnum, cmd | __IPC_64, &arg);
 113     if (result != -1 || errno != EINVAL)
 114       return result;
 115
 116     __set_errno(save_errno);
 117     buf = arg.buf;
 118     arg.buf = (struct semid_ds *)&old;
 119     if (cmd == IPC_SET)
 120       {
 121         old.sem_perm.uid = buf->sem_perm.uid;
 122         old.sem_perm.gid = buf->sem_perm.gid;
 123         old.sem_perm.mode = buf->sem_perm.mode;
 124         if (old.sem_perm.uid != buf->sem_perm.uid ||
 125             old.sem_perm.gid != buf->sem_perm.gid)
 126           {
 127             __set_errno (EINVAL);
 128             return -1;
 129           }
 130       }
 131     result = INLINE_SYSCALL (ipc, 5, IPCOP_semctl, semid, semnum, cmd, &arg);
 132     if (result != -1 && cmd != IPC_SET)
 133       {
 134         memset(buf, 0, sizeof(*buf));
 135         buf->sem_perm.__key = old.sem_perm.__key;
 136         buf->sem_perm.uid = old.sem_perm.uid;
 137         buf->sem_perm.gid = old.sem_perm.gid;
 138         buf->sem_perm.cuid = old.sem_perm.cuid;
 139         buf->sem_perm.cgid = old.sem_perm.cgid;
 140         buf->sem_perm.mode = old.sem_perm.mode;
 141         buf->sem_perm.__seq = old.sem_perm.__seq;
 142         buf->sem_otime = old.sem_otime;
 143         buf->sem_ctime = old.sem_ctime;
 144         buf->sem_nsems = old.sem_nsems;
 145       }
 146     return result;
 147   }
 148 #endif
 149 }
 150
 151 versioned_symbol (libc, __new_semctl, semctl, GLIBC_2_2);