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, see
  18    <http://www.gnu.org/licenses/>.  */
  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   struct __old_semid_ds *__old_buf;
  52 };
  53
  54 #include <bp-checks.h>
  55 #include <bp-semctl.h>          /* definition of CHECK_SEMCTL needs union semum */
  56
  57 /* Return identifier for array of NSEMS semaphores associated with
  58    KEY.  */
  59 #if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_2)
  60 int __old_semctl (int semid, int semnum, int cmd, ...);
  61 #endif
  62 int __new_semctl (int semid, int semnum, int cmd, ...);
  63
  64 #if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_2)
  65 int
  66 attribute_compat_text_section
  67 __old_semctl (int semid, int semnum, int cmd, ...)
  68 {
  69   union semun arg;
  70   va_list ap;
  71
  72   va_start (ap, cmd);
  73
  74   /* Get the argument only if required.  */
  75   arg.buf = NULL;
  76   switch (cmd)
  77     {
  78     case SETVAL:        /* arg.val */
  79     case GETALL:        /* arg.array */
  80     case SETALL:
  81     case IPC_STAT:      /* arg.buf */
  82     case IPC_SET:
  83     case SEM_STAT:
  84     case IPC_INFO:      /* arg.__buf */
  85     case SEM_INFO:
  86       va_start (ap, cmd);
  87       arg = va_arg (ap, union semun);
  88       va_end (ap);
  89       break;
  90     }
  91
  92   va_end (ap);
  93
  94   return INLINE_SYSCALL (ipc, 5, IPCOP_semctl, semid, semnum, cmd,
  95                          CHECK_SEMCTL (&arg, semid, cmd));
  96 }
  97 compat_symbol (libc, __old_semctl, semctl, GLIBC_2_0);
  98 #endif
  99
 100 int
 101 __new_semctl (int semid, int semnum, int cmd, ...)
 102 {
 103   union semun arg;
 104   va_list ap;
 105
 106   va_start (ap, cmd);
 107
 108   /* Get the argument only if required.  */
 109   arg.buf = NULL;
 110   switch (cmd)
 111     {
 112     case SETVAL:        /* arg.val */
 113     case GETALL:        /* arg.array */
 114     case SETALL:
 115     case IPC_STAT:      /* arg.buf */
 116     case IPC_SET:
 117     case SEM_STAT:
 118     case IPC_INFO:      /* arg.__buf */
 119     case SEM_INFO:
 120       va_start (ap, cmd);
 121       arg = va_arg (ap, union semun);
 122       va_end (ap);
 123       break;
 124     }
 125
 126   va_end (ap);
 127
 128 #if __ASSUME_IPC64 > 0
 129   return INLINE_SYSCALL (ipc, 5, IPCOP_semctl, semid, semnum, cmd | __IPC_64,
 130                          CHECK_SEMCTL (&arg, semid, cmd | __IPC_64));
 131 #else
 132   switch (cmd)
 133     {
 134     case SEM_STAT:
 135     case IPC_STAT:
 136     case IPC_SET:
 137       break;
 138     default:
 139       return INLINE_SYSCALL (ipc, 5, IPCOP_semctl, semid, semnum, cmd,
 140                              CHECK_SEMCTL (&arg, semid, cmd));
 141     }
 142
 143   {
 144     int save_errno = errno, result;
 145     struct __old_semid_ds old;
 146     struct semid_ds *buf;
 147
 148     /* Unfortunately there is no way how to find out for sure whether
 149        we should use old or new semctl.  */
 150     result = INLINE_SYSCALL (ipc, 5, IPCOP_semctl, semid, semnum, cmd | __IPC_64,
 151                              CHECK_SEMCTL (&arg, semid, cmd | __IPC_64));
 152     if (result != -1 || errno != EINVAL)
 153       return result;
 154
 155     __set_errno(save_errno);
 156     buf = arg.buf;
 157     arg.__old_buf = &old;
 158     if (cmd == IPC_SET)
 159       {
 160         old.sem_perm.uid = buf->sem_perm.uid;
 161         old.sem_perm.gid = buf->sem_perm.gid;
 162         old.sem_perm.mode = buf->sem_perm.mode;
 163         if (old.sem_perm.uid != buf->sem_perm.uid ||
 164             old.sem_perm.gid != buf->sem_perm.gid)
 165           {
 166             __set_errno (EINVAL);
 167             return -1;
 168           }
 169       }
 170     result = INLINE_SYSCALL (ipc, 5, IPCOP_semctl, semid, semnum, cmd,
 171                              CHECK_SEMCTL (&arg, semid, cmd));
 172     if (result != -1 && cmd != IPC_SET)
 173       {
 174         memset(buf, 0, sizeof(*buf));
 175         buf->sem_perm.__key = old.sem_perm.__key;
 176         buf->sem_perm.uid = old.sem_perm.uid;
 177         buf->sem_perm.gid = old.sem_perm.gid;
 178         buf->sem_perm.cuid = old.sem_perm.cuid;
 179         buf->sem_perm.cgid = old.sem_perm.cgid;
 180         buf->sem_perm.mode = old.sem_perm.mode;
 181         buf->sem_perm.__seq = old.sem_perm.__seq;
 182         buf->sem_otime = old.sem_otime;
 183         buf->sem_ctime = old.sem_ctime;
 184         buf->sem_nsems = old.sem_nsems;
 185       }
 186     return result;
 187   }
 188 #endif
 189 }
 190
 191 versioned_symbol (libc, __new_semctl, semctl, GLIBC_2_2);