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 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 #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 *__unbounded __sembase;    /* ptr to first semaphore in array */
  38   struct sem_queue *__unbounded __sem_pending; /* pending operations */
  39   struct sem_queue *__unbounded __sem_pending_last; /* last pending operation */
  40   struct sem_undo *__unbounded __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 #if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_2)
  59 int __old_semctl (int semid, int semnum, int cmd, ...);
  60 #endif
  61 int __new_semctl (int semid, int semnum, int cmd, ...);
  62
  63 #if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_2)
  64 int
  65 __old_semctl (int semid, int semnum, int cmd, ...)
  66 {
  67   union semun arg;
  68   va_list ap;
  69
  70   va_start (ap, cmd);
  71
  72   /* Get the argument only if required.  */
  73   arg.buf = NULL;
  74   switch (cmd)
  75     {
  76     case SETVAL:        /* arg.val */
  77     case GETALL:        /* arg.array */
  78     case SETALL:
  79     case IPC_STAT:      /* arg.buf */
  80     case IPC_SET:
  81     case SEM_STAT:
  82     case IPC_INFO:      /* arg.__buf */
  83     case SEM_INFO:
  84       va_start (ap, cmd);
  85       arg = va_arg (ap, union semun);
  86       va_end (ap);
  87       break;
  88     }
  89
  90   va_end (ap);
  91
  92   return INLINE_SYSCALL (ipc, 5, IPCOP_semctl, semid, semnum, cmd,
  93                          CHECK_SEMCTL (&arg, semid, cmd));
  94 }
  95 compat_symbol (libc, __old_semctl, semctl, GLIBC_2_0);
  96 #endif
  97
  98 int
  99 __new_semctl (int semid, int semnum, int cmd, ...)
 100 {
 101   union semun arg;
 102   va_list ap;
 103
 104   va_start (ap, cmd);
 105
 106   /* Get the argument only if required.  */
 107   arg.buf = NULL;
 108   switch (cmd)
 109     {
 110     case SETVAL:        /* arg.val */
 111     case GETALL:        /* arg.array */
 112     case SETALL:
 113     case IPC_STAT:      /* arg.buf */
 114     case IPC_SET:
 115     case SEM_STAT:
 116     case IPC_INFO:      /* arg.__buf */
 117     case SEM_INFO:
 118       va_start (ap, cmd);
 119       arg = va_arg (ap, union semun);
 120       va_end (ap);
 121       break;
 122     }
 123
 124   va_end (ap);
 125
 126 #if __ASSUME_IPC64 > 0
 127   return INLINE_SYSCALL (ipc, 5, IPCOP_semctl, semid, semnum, cmd | __IPC_64,
 128                          CHECK_SEMCTL (&arg, semid, cmd | __IPC_64));
 129 #else
 130   switch (cmd)
 131     {
 132     case SEM_STAT:
 133     case IPC_STAT:
 134     case IPC_SET:
 135       break;
 136     default:
 137       return INLINE_SYSCALL (ipc, 5, IPCOP_semctl, semid, semnum, cmd,
 138                              CHECK_SEMCTL (&arg, semid, cmd));
 139     }
 140
 141   {
 142     int save_errno = errno, result;
 143     struct __old_semid_ds old;
 144     struct semid_ds *buf;
 145
 146     /* Unfortunately there is no way how to find out for sure whether
 147        we should use old or new semctl.  */
 148     result = INLINE_SYSCALL (ipc, 5, IPCOP_semctl, semid, semnum, cmd | __IPC_64,
 149                              CHECK_SEMCTL (&arg, semid, cmd | __IPC_64));
 150     if (result != -1 || errno != EINVAL)
 151       return result;
 152
 153     __set_errno(save_errno);
 154     buf = arg.buf;
 155     arg.buf = (struct semid_ds *)&old;
 156     if (cmd == IPC_SET)
 157       {
 158         old.sem_perm.uid = buf->sem_perm.uid;
 159         old.sem_perm.gid = buf->sem_perm.gid;
 160         old.sem_perm.mode = buf->sem_perm.mode;
 161         if (old.sem_perm.uid != buf->sem_perm.uid ||
 162             old.sem_perm.gid != buf->sem_perm.gid)
 163           {
 164             __set_errno (EINVAL);
 165             return -1;
 166           }
 167       }
 168     result = INLINE_SYSCALL (ipc, 5, IPCOP_semctl, semid, semnum, cmd,
 169                              CHECK_SEMCTL (&arg, semid, cmd));
 170     if (result != -1 && cmd != IPC_SET)
 171       {
 172         memset(buf, 0, sizeof(*buf));
 173         buf->sem_perm.__key = old.sem_perm.__key;
 174         buf->sem_perm.uid = old.sem_perm.uid;
 175         buf->sem_perm.gid = old.sem_perm.gid;
 176         buf->sem_perm.cuid = old.sem_perm.cuid;
 177         buf->sem_perm.cgid = old.sem_perm.cgid;
 178         buf->sem_perm.mode = old.sem_perm.mode;
 179         buf->sem_perm.__seq = old.sem_perm.__seq;
 180         buf->sem_otime = old.sem_otime;
 181         buf->sem_ctime = old.sem_ctime;
 182         buf->sem_nsems = old.sem_nsems;
 183       }
 184     return result;
 185   }
 186 #endif
 187 }
 188
 189 versioned_symbol (libc, __new_semctl, semctl, GLIBC_2_2);