sysdeps/unix/sysv/linux/semctl.c

   1 /* Copyright (C) 1995-2018 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 <sys/sem.h>
  20 #include <stdarg.h>
  21 #include <ipc_priv.h>
  22 #include <sysdep.h>
  23 #include <shlib-compat.h>
  24 #include <errno.h>
  25
  26 /* Define a `union semun' suitable for Linux here.  */
  27 union semun
  28 {
  29   int val;                      /* value for SETVAL */
  30   struct semid_ds *buf;         /* buffer for IPC_STAT & IPC_SET */
  31   unsigned short int *array;    /* array for GETALL & SETALL */
  32   struct seminfo *__buf;        /* buffer for IPC_INFO */
  33 };
  34
  35 #ifndef DEFAULT_VERSION
  36 # define DEFAULT_VERSION GLIBC_2_2
  37 #endif
  38
  39 int
  40 __new_semctl (int semid, int semnum, int cmd, ...)
  41 {
  42   union semun arg = { 0 };
  43   va_list ap;
  44
  45   /* Get the argument only if required.  */
  46   switch (cmd)
  47     {
  48     case SETVAL:        /* arg.val */
  49     case GETALL:        /* arg.array */
  50     case SETALL:
  51     case IPC_STAT:      /* arg.buf */
  52     case IPC_SET:
  53     case SEM_STAT:
  54     case IPC_INFO:      /* arg.__buf */
  55     case SEM_INFO:
  56       va_start (ap, cmd);
  57       arg = va_arg (ap, union semun);
  58       va_end (ap);
  59       break;
  60     }
  61
  62 #ifdef __ASSUME_DIRECT_SYSVIPC_SYSCALLS
  63   return INLINE_SYSCALL_CALL (semctl, semid, semnum, cmd | __IPC_64,
  64                               arg.array);
  65 #else
  66   return INLINE_SYSCALL_CALL (ipc, IPCOP_semctl, semid, semnum, cmd | __IPC_64,
  67                               SEMCTL_ARG_ADDRESS (arg));
  68 #endif
  69 }
  70 versioned_symbol (libc, __new_semctl, semctl, DEFAULT_VERSION);
  71
  72
  73 #if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_2)
  74 /* Since semctl use a variadic argument for semid_ds there is not need to
  75    define and tie the compatibility symbol to the old 'union semun'
  76    definition.  */
  77 int
  78 attribute_compat_text_section
  79 __old_semctl (int semid, int semnum, int cmd, ...)
  80 {
  81   union semun arg = { 0 };
  82   va_list ap;
  83
  84   /* Get the argument only if required.  */
  85   switch (cmd)
  86     {
  87     case SETVAL:        /* arg.val */
  88     case GETALL:        /* arg.array */
  89     case SETALL:
  90     case IPC_STAT:      /* arg.buf */
  91     case IPC_SET:
  92     case SEM_STAT:
  93     case IPC_INFO:      /* arg.__buf */
  94     case SEM_INFO:
  95       va_start (ap, cmd);
  96       arg = va_arg (ap, union semun);
  97       va_end (ap);
  98       break;
  99     }
 100
 101 # ifdef __ASSUME_DIRECT_SYSVIPC_SYSCALLS
 102   return INLINE_SYSCALL_CALL (semctl, semid, semnum, cmd, arg.array);
 103 # else
 104   return INLINE_SYSCALL_CALL (ipc, IPCOP_semctl, semid, semnum, cmd,
 105                               SEMCTL_ARG_ADDRESS (arg));
 106 # endif
 107 }
 108 compat_symbol (libc, __old_semctl, semctl, GLIBC_2_0);
 109 #endif