sysdeps/unix/sysv/linux/msgctl.c

   1 /* Copyright (C) 1995-2020 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    <https://www.gnu.org/licenses/>.  */
  18
  19 #include <sys/msg.h>
  20 #include <ipc_priv.h>
  21 #include <sysdep.h>
  22 #include <shlib-compat.h>
  23 #include <errno.h>
  24
  25 #ifndef DEFAULT_VERSION
  26 # ifndef __ASSUME_SYSVIPC_BROKEN_MODE_T
  27 #  define DEFAULT_VERSION GLIBC_2_2
  28 # else
  29 #  define DEFAULT_VERSION GLIBC_2_31
  30 # endif
  31 #endif
  32
  33 static int
  34 msgctl_syscall (int msqid, int cmd, struct msqid_ds *buf)
  35 {
  36 #ifdef __ASSUME_DIRECT_SYSVIPC_SYSCALLS
  37   return INLINE_SYSCALL_CALL (msgctl, msqid, cmd | __IPC_64, buf);
  38 #else
  39   return INLINE_SYSCALL_CALL (ipc, IPCOP_msgctl, msqid, cmd | __IPC_64, 0,
  40                               buf);
  41 #endif
  42 }
  43
  44 int
  45 __new_msgctl (int msqid, int cmd, struct msqid_ds *buf)
  46 {
  47   /* POSIX states ipc_perm mode should have type of mode_t.  */
  48   _Static_assert (sizeof ((struct msqid_ds){0}.msg_perm.mode)
  49                   == sizeof (mode_t),
  50                   "sizeof (msqid_ds.msg_perm.mode) != sizeof (mode_t)");
  51
  52 #ifdef __ASSUME_SYSVIPC_BROKEN_MODE_T
  53   struct msqid_ds tmpds;
  54   if (cmd == IPC_SET)
  55     {
  56       tmpds = *buf;
  57       tmpds.msg_perm.mode *= 0x10000U;
  58       buf = &tmpds;
  59     }
  60 #endif
  61
  62   int ret = msgctl_syscall (msqid, cmd, buf);
  63
  64   if (ret >= 0)
  65     {
  66       switch (cmd)
  67         {
  68         case IPC_STAT:
  69         case MSG_STAT:
  70         case MSG_STAT_ANY:
  71 #ifdef __ASSUME_SYSVIPC_BROKEN_MODE_T
  72           buf->msg_perm.mode >>= 16;
  73 #else
  74           /* Old Linux kernel versions might not clear the mode padding.  */
  75           if (sizeof ((struct msqid_ds){0}.msg_perm.mode)
  76               != sizeof (__kernel_mode_t))
  77             buf->msg_perm.mode &= 0xFFFF;
  78 #endif
  79         }
  80     }
  81
  82   return ret;
  83 }
  84 versioned_symbol (libc, __new_msgctl, msgctl, DEFAULT_VERSION);
  85
  86 #if defined __ASSUME_SYSVIPC_BROKEN_MODE_T \
  87     && SHLIB_COMPAT (libc, GLIBC_2_2, GLIBC_2_31)
  88 int
  89 attribute_compat_text_section
  90 __msgctl_mode16 (int msqid, int cmd, struct msqid_ds *buf)
  91 {
  92   return msgctl_syscall (msqid, cmd, buf);
  93 }
  94 compat_symbol (libc, __msgctl_mode16, msgctl, GLIBC_2_2);
  95 #endif
  96
  97 #if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_2)
  98 struct __old_msqid_ds
  99 {
 100   struct __old_ipc_perm msg_perm;       /* structure describing operation permission */
 101   struct msg *__msg_first;              /* pointer to first message on queue */
 102   struct msg *__msg_last;               /* pointer to last message on queue */
 103   __time_t msg_stime;                   /* time of last msgsnd command */
 104   __time_t msg_rtime;                   /* time of last msgrcv command */
 105   __time_t msg_ctime;                   /* time of last change */
 106   struct wait_queue *__wwait;           /* ??? */
 107   struct wait_queue *__rwait;           /* ??? */
 108   unsigned short int __msg_cbytes;      /* current number of bytes on queue */
 109   unsigned short int msg_qnum;          /* number of messages currently on queue */
 110   unsigned short int msg_qbytes;        /* max number of bytes allowed on queue */
 111   __ipc_pid_t msg_lspid;                /* pid of last msgsnd() */
 112   __ipc_pid_t msg_lrpid;                /* pid of last msgrcv() */
 113 };
 114
 115 int
 116 attribute_compat_text_section
 117 __old_msgctl (int msqid, int cmd, struct __old_msqid_ds *buf)
 118 {
 119 #if defined __ASSUME_DIRECT_SYSVIPC_SYSCALLS \
 120     && !defined __ASSUME_SYSVIPC_DEFAULT_IPC_64
 121   /* For architecture that have wire-up msgctl but also have __IPC_64 to a
 122      value different than default (0x0) it means the compat symbol used the
 123      __NR_ipc syscall.  */
 124   return INLINE_SYSCALL_CALL (msgctl, msqid, cmd, buf);
 125 #else
 126   return INLINE_SYSCALL_CALL (ipc, IPCOP_msgctl, msqid, cmd, 0, buf);
 127 #endif
 128 }
 129 compat_symbol (libc, __old_msgctl, msgctl, GLIBC_2_0);
 130 #endif