sysdeps/unix/sysv/linux/semctl.c

   1 /* Copyright (C) 1995,1997,1998,2000,2003,2004,2006
   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 #include <shlib-compat.h>
  30
  31 #include <kernel-features.h>
  32
  33 struct __old_semid_ds
  34 {
  35   struct __old_ipc_perm sem_perm;       /* operation permission struct */
  36   __time_t sem_otime;                   /* last semop() time */
  37   __time_t sem_ctime;                   /* last time changed by semctl() */
  38   struct sem *__unbounded __sembase;    /* ptr to first semaphore in array */
  39   struct sem_queue *__unbounded __sem_pending; /* pending operations */
  40   struct sem_queue *__unbounded __sem_pending_last; /* last pending operation */
  41   struct sem_undo *__unbounded __undo;  /* ondo requests on this array */
  42   unsigned short int sem_nsems;         /* number of semaphores in set */
  43 };
  44
  45 /* Define a `union semun' suitable for Linux here.  */
  46 union semun
  47 {
  48   int val;                      /* value for SETVAL */
  49   struct semid_ds *buf;         /* buffer for IPC_STAT & IPC_SET */
  50   unsigned short int *array;    /* array for GETALL & SETALL */
  51   struct seminfo *__buf;        /* buffer for IPC_INFO */
  52   struct __old_semid_ds *__old_buf;
  53 };
  54
  55 #include <bp-checks.h>
  56 #include <bp-semctl.h>          /* definition of CHECK_SEMCTL needs union semum */
  57
  58 /* Return identifier for array of NSEMS semaphores associated with
  59    KEY.  */
  60 #if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_2)
  61 int __old_semctl (int semid, int semnum, int cmd, ...);
  62 #endif
  63 int __new_semctl (int semid, int semnum, int cmd, ...);
  64
  65 #if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_2)
  66 int
  67 attribute_compat_text_section
  68 __old_semctl (int semid, int semnum, int cmd, ...)
  69 {
  70   union semun arg;
  71   va_list ap;
  72
  73   va_start (ap, cmd);
  74
  75   /* Get the argument only if required.  */
  76   arg.buf = NULL;
  77   switch (cmd)
  78     {
  79     case SETVAL:        /* arg.val */
  80     case GETALL:        /* arg.array */
  81     case SETALL:
  82     case IPC_STAT:      /* arg.buf */
  83     case IPC_SET:
  84     case SEM_STAT:
  85     case IPC_INFO:      /* arg.__buf */
  86     case SEM_INFO:
  87       va_start (ap, cmd);
  88       arg = va_arg (ap, union semun);
  89       va_end (ap);
  90       break;
  91     }
  92
  93   va_end (ap);
  94
  95   return INLINE_SYSCALL (ipc, 5, IPCOP_semctl, semid, semnum, cmd,
  96                          CHECK_SEMCTL (&arg, semid, cmd));
  97 }
  98 compat_symbol (libc, __old_semctl, semctl, GLIBC_2_0);
  99 #endif
 100
 101 int
 102 __new_semctl (int semid, int semnum, int cmd, ...)
 103 {
 104   union semun arg;
 105   va_list ap;
 106
 107   va_start (ap, cmd);
 108
 109   /* Get the argument only if required.  */
 110   arg.buf = NULL;
 111   switch (cmd)
 112     {
 113     case SETVAL:        /* arg.val */
 114     case GETALL:        /* arg.array */
 115     case SETALL:
 116     case IPC_STAT:      /* arg.buf */
 117     case IPC_SET:
 118     case SEM_STAT:
 119     case IPC_INFO:      /* arg.__buf */
 120     case SEM_INFO:
 121       va_start (ap, cmd);
 122       arg = va_arg (ap, union semun);
 123       va_end (ap);
 124       break;
 125     }
 126
 127   va_end (ap);
 128
 129 #if __ASSUME_IPC64 > 0
 130   return INLINE_SYSCALL (ipc, 5, IPCOP_semctl, semid, semnum, cmd | __IPC_64,
 131                          CHECK_SEMCTL (&arg, semid, cmd | __IPC_64));
 132 #else
 133   switch (cmd)
 134     {
 135     case SEM_STAT:
 136     case IPC_STAT:
 137     case IPC_SET:
 138       break;
 139     default:
 140       return INLINE_SYSCALL (ipc, 5, IPCOP_semctl, semid, semnum, cmd,
 141                              CHECK_SEMCTL (&arg, semid, cmd));
 142     }
 143
 144   {
 145     int save_errno = errno, result;
 146     struct __old_semid_ds old;
 147     struct semid_ds *buf;
 148
 149     /* Unfortunately there is no way how to find out for sure whether
 150        we should use old or new semctl.  */
 151     result = INLINE_SYSCALL (ipc, 5, IPCOP_semctl, semid, semnum, cmd | __IPC_64,
 152                              CHECK_SEMCTL (&arg, semid, cmd | __IPC_64));
 153     if (result != -1 || errno != EINVAL)
 154       return result;
 155
 156     __set_errno(save_errno);
 157     buf = arg.buf;
 158     arg.__old_buf = &old;
 159     if (cmd == IPC_SET)
 160       {
 161         old.sem_perm.uid = buf->sem_perm.uid;
 162         old.sem_perm.gid = buf->sem_perm.gid;
 163         old.sem_perm.mode = buf->sem_perm.mode;
 164         if (old.sem_perm.uid != buf->sem_perm.uid ||
 165             old.sem_perm.gid != buf->sem_perm.gid)
 166           {
 167             __set_errno (EINVAL);
 168             return -1;
 169           }
 170       }
 171     result = INLINE_SYSCALL (ipc, 5, IPCOP_semctl, semid, semnum, cmd,
 172                              CHECK_SEMCTL (&arg, semid, cmd));
 173     if (result != -1 && cmd != IPC_SET)
 174       {
 175         memset(buf, 0, sizeof(*buf));
 176         buf->sem_perm.__key = old.sem_perm.__key;
 177         buf->sem_perm.uid = old.sem_perm.uid;
 178         buf->sem_perm.gid = old.sem_perm.gid;
 179         buf->sem_perm.cuid = old.sem_perm.cuid;
 180         buf->sem_perm.cgid = old.sem_perm.cgid;
 181         buf->sem_perm.mode = old.sem_perm.mode;
 182         buf->sem_perm.__seq = old.sem_perm.__seq;
 183         buf->sem_otime = old.sem_otime;
 184         buf->sem_ctime = old.sem_ctime;
 185         buf->sem_nsems = old.sem_nsems;
 186       }
 187     return result;
 188   }
 189 #endif
 190 }
 191
 192 versioned_symbol (libc, __new_semctl, semctl, GLIBC_2_2);