sysdeps/unix/sysv/linux/semctl.c

   1 /* Copyright (C) 1995-2016 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 *__sembase;                /* ptr to first semaphore in array */
  37   struct sem_queue *__sem_pending;      /* pending operations */
  38   struct sem_queue *__sem_pending_last; /* last pending operation */
  39   struct sem_undo *__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 /* Return identifier for array of NSEMS semaphores associated with
  54    KEY.  */
  55 #if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_2)
  56 int __old_semctl (int semid, int semnum, int cmd, ...);
  57 #endif
  58 int __new_semctl (int semid, int semnum, int cmd, ...);
  59
  60 #if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_2)
  61 int
  62 attribute_compat_text_section
  63 __old_semctl (int semid, int semnum, int cmd, ...)
  64 {
  65   union semun arg;
  66   va_list ap;
  67
  68   /* Get the argument only if required.  */
  69   arg.buf = NULL;
  70   switch (cmd)
  71     {
  72     case SETVAL:        /* arg.val */
  73     case GETALL:        /* arg.array */
  74     case SETALL:
  75     case IPC_STAT:      /* arg.buf */
  76     case IPC_SET:
  77     case SEM_STAT:
  78     case IPC_INFO:      /* arg.__buf */
  79     case SEM_INFO:
  80       va_start (ap, cmd);
  81       arg = va_arg (ap, union semun);
  82       va_end (ap);
  83       break;
  84     }
  85
  86   return INLINE_SYSCALL (ipc, 5, IPCOP_semctl, semid, semnum, cmd,
  87                          &arg);
  88 }
  89 compat_symbol (libc, __old_semctl, semctl, GLIBC_2_0);
  90 #endif
  91
  92 int
  93 __new_semctl (int semid, int semnum, int cmd, ...)
  94 {
  95   union semun arg;
  96   va_list ap;
  97
  98   /* Get the argument only if required.  */
  99   arg.buf = NULL;
 100   switch (cmd)
 101     {
 102     case SETVAL:        /* arg.val */
 103     case GETALL:        /* arg.array */
 104     case SETALL:
 105     case IPC_STAT:      /* arg.buf */
 106     case IPC_SET:
 107     case SEM_STAT:
 108     case IPC_INFO:      /* arg.__buf */
 109     case SEM_INFO:
 110       va_start (ap, cmd);
 111       arg = va_arg (ap, union semun);
 112       va_end (ap);
 113       break;
 114     }
 115
 116   return INLINE_SYSCALL (ipc, 5, IPCOP_semctl, semid, semnum, cmd | __IPC_64,
 117                          &arg);
 118 }
 119
 120 versioned_symbol (libc, __new_semctl, semctl, GLIBC_2_2);