sysdeps/unix/sysv/linux/semctl.c

   1 /* Copyright (C) 1995-2012 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, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <errno.h>
  20 #include <stdarg.h>
  21 #include <sys/sem.h>
  22 #include <ipc_priv.h>
  23
  24 #include <sysdep.h>
  25 #include <string.h>
  26 #include <sys/syscall.h>
  27 #include <shlib-compat.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 *__unbounded __sembase;    /* ptr to first semaphore in array */
  37   struct sem_queue *__unbounded __sem_pending; /* pending operations */
  38   struct sem_queue *__unbounded __sem_pending_last; /* last pending operation */
  39   struct sem_undo *__unbounded __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   struct __old_semid_ds *__old_buf;
  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 attribute_compat_text_section
  66 __old_semctl (int semid, int semnum, int cmd, ...)
  67 {
  68   union semun arg;
  69   va_list ap;
  70
  71   va_start (ap, cmd);
  72
  73   /* Get the argument only if required.  */
  74   arg.buf = NULL;
  75   switch (cmd)
  76     {
  77     case SETVAL:        /* arg.val */
  78     case GETALL:        /* arg.array */
  79     case SETALL:
  80     case IPC_STAT:      /* arg.buf */
  81     case IPC_SET:
  82     case SEM_STAT:
  83     case IPC_INFO:      /* arg.__buf */
  84     case SEM_INFO:
  85       va_start (ap, cmd);
  86       arg = va_arg (ap, union semun);
  87       va_end (ap);
  88       break;
  89     }
  90
  91   va_end (ap);
  92
  93   return INLINE_SYSCALL (ipc, 5, IPCOP_semctl, semid, semnum, cmd,
  94                          CHECK_SEMCTL (&arg, semid, cmd));
  95 }
  96 compat_symbol (libc, __old_semctl, semctl, GLIBC_2_0);
  97 #endif
  98
  99 int
 100 __new_semctl (int semid, int semnum, int cmd, ...)
 101 {
 102   union semun arg;
 103   va_list ap;
 104
 105   va_start (ap, cmd);
 106
 107   /* Get the argument only if required.  */
 108   arg.buf = NULL;
 109   switch (cmd)
 110     {
 111     case SETVAL:        /* arg.val */
 112     case GETALL:        /* arg.array */
 113     case SETALL:
 114     case IPC_STAT:      /* arg.buf */
 115     case IPC_SET:
 116     case SEM_STAT:
 117     case IPC_INFO:      /* arg.__buf */
 118     case SEM_INFO:
 119       va_start (ap, cmd);
 120       arg = va_arg (ap, union semun);
 121       va_end (ap);
 122       break;
 123     }
 124
 125   va_end (ap);
 126
 127 #if __ASSUME_IPC64 > 0
 128   return INLINE_SYSCALL (ipc, 5, IPCOP_semctl, semid, semnum, cmd | __IPC_64,
 129                          CHECK_SEMCTL (&arg, semid, cmd | __IPC_64));
 130 #else
 131   switch (cmd)
 132     {
 133     case SEM_STAT:
 134     case IPC_STAT:
 135     case IPC_SET:
 136       break;
 137     default:
 138       return INLINE_SYSCALL (ipc, 5, IPCOP_semctl, semid, semnum, cmd,
 139                              CHECK_SEMCTL (&arg, semid, cmd));
 140     }
 141
 142   {
 143     int save_errno = errno, result;
 144     struct __old_semid_ds old;
 145     struct semid_ds *buf;
 146
 147     /* Unfortunately there is no way how to find out for sure whether
 148        we should use old or new semctl.  */
 149     result = INLINE_SYSCALL (ipc, 5, IPCOP_semctl, semid, semnum, cmd | __IPC_64,
 150                              CHECK_SEMCTL (&arg, semid, cmd | __IPC_64));
 151     if (result != -1 || errno != EINVAL)
 152       return result;
 153
 154     __set_errno(save_errno);
 155     buf = arg.buf;
 156     arg.__old_buf = &old;
 157     if (cmd == IPC_SET)
 158       {
 159         old.sem_perm.uid = buf->sem_perm.uid;
 160         old.sem_perm.gid = buf->sem_perm.gid;
 161         old.sem_perm.mode = buf->sem_perm.mode;
 162         if (old.sem_perm.uid != buf->sem_perm.uid ||
 163             old.sem_perm.gid != buf->sem_perm.gid)
 164           {
 165             __set_errno (EINVAL);
 166             return -1;
 167           }
 168       }
 169     result = INLINE_SYSCALL (ipc, 5, IPCOP_semctl, semid, semnum, cmd,
 170                              CHECK_SEMCTL (&arg, semid, cmd));
 171     if (result != -1 && cmd != IPC_SET)
 172       {
 173         memset(buf, 0, sizeof(*buf));
 174         buf->sem_perm.__key = old.sem_perm.__key;
 175         buf->sem_perm.uid = old.sem_perm.uid;
 176         buf->sem_perm.gid = old.sem_perm.gid;
 177         buf->sem_perm.cuid = old.sem_perm.cuid;
 178         buf->sem_perm.cgid = old.sem_perm.cgid;
 179         buf->sem_perm.mode = old.sem_perm.mode;
 180         buf->sem_perm.__seq = old.sem_perm.__seq;
 181         buf->sem_otime = old.sem_otime;
 182         buf->sem_ctime = old.sem_ctime;
 183         buf->sem_nsems = old.sem_nsems;
 184       }
 185     return result;
 186   }
 187 #endif
 188 }
 189
 190 versioned_symbol (libc, __new_semctl, semctl, GLIBC_2_2);