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ffd178c651
To provide a y2038 safe interface a new symbol __shmctl64 is added
and __shmctl is change to call it instead (it adds some extra buffer
copying for the 32 bit time_t implementation).
Two new structures are added:
1. kernel_shmid64_ds: used internally only on 32-bit architectures
to issue the syscall. A handful of architectures (hppa, i386,
mips, powerpc32, and sparc32) require specific implementations
due to their kernel ABI.
2. shmid_ds64: this is only for __TIMESIZE != 64 to use along with
the 64-bit shmctl. It is different than the kernel struct because
the exported 64-bit time_t might require different alignment
depending on the architecture ABI.
So the resulting implementation does:
1. For 64-bit architectures it assumes shmid_ds already contains
64-bit time_t fields and will result in just the __shmctl symbol
using the __shmctl64 code. The shmid_ds argument is passed as-is
to the syscall.
2. For 32-bit architectures with default 64-bit time_t (newer ABIs
such riscv32 or arc), it will also result in only one exported
symbol but with the required high/low time handling.
3. Finally for 32-bit architecture with both 32-bit and 64-bit time_t
support we follow the already set way to provide one symbol with
64-bit time_t support and implement the 32-bit time_t support
using of the 64-bit one.
The default 32-bit symbol will allocate and copy the shmid_ds
over multiple buffers, but this should be deprecated in favor
of the __shmctl64 anyway.
Checked on i686-linux-gnu and x86_64-linux-gnu. I also did some sniff
tests on powerpc, powerpc64, mips, mips64, armhf, sparcv9, and
sparc64.
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Tested-by: Alistair Francis <alistair.francis@wdc.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
245 lines
7.2 KiB
C
245 lines
7.2 KiB
C
/* Copyright (C) 1995-2020 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Ulrich Drepper <drepper@gnu.ai.mit.edu>, August 1995.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#include <sys/shm.h>
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#include <stdarg.h>
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#include <ipc_priv.h>
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#include <sysdep.h>
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#include <shlib-compat.h>
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#include <errno.h>
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#include <linux/posix_types.h> /* For __kernel_mode_t. */
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/* POSIX states ipc_perm mode should have type of mode_t. */
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_Static_assert (sizeof ((struct shmid_ds){0}.shm_perm.mode)
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== sizeof (mode_t),
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"sizeof (shmid_ds.shm_perm.mode) != sizeof (mode_t)");
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#if __IPC_TIME64 == 0
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typedef struct shmid_ds shmctl_arg_t;
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#else
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# include <struct_kernel_shmid64_ds.h>
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static void
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shmid64_to_kshmid64 (const struct __shmid64_ds *shmid64,
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struct kernel_shmid64_ds *kshmid)
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{
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kshmid->shm_perm = shmid64->shm_perm;
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kshmid->shm_segsz = shmid64->shm_segsz;
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kshmid->shm_atime = shmid64->shm_atime;
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kshmid->shm_atime_high = shmid64->shm_atime >> 32;
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kshmid->shm_dtime = shmid64->shm_dtime;
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kshmid->shm_dtime_high = shmid64->shm_dtime >> 32;
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kshmid->shm_ctime = shmid64->shm_ctime;
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kshmid->shm_ctime_high = shmid64->shm_ctime >> 32;
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kshmid->shm_cpid = shmid64->shm_cpid;
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kshmid->shm_lpid = shmid64->shm_lpid;
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kshmid->shm_nattch = shmid64->shm_nattch;
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}
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static void
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kshmid64_to_shmid64 (const struct kernel_shmid64_ds *kshmid,
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struct __shmid64_ds *shmid64)
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{
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shmid64->shm_perm = kshmid->shm_perm;
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shmid64->shm_segsz = kshmid->shm_segsz;
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shmid64->shm_atime = kshmid->shm_atime
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| ((__time64_t) kshmid->shm_atime_high << 32);
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shmid64->shm_dtime = kshmid->shm_dtime
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| ((__time64_t) kshmid->shm_dtime_high << 32);
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shmid64->shm_ctime = kshmid->shm_ctime
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| ((__time64_t) kshmid->shm_ctime_high << 32);
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shmid64->shm_cpid = kshmid->shm_cpid;
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shmid64->shm_lpid = kshmid->shm_lpid;
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shmid64->shm_nattch = kshmid->shm_nattch;
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}
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typedef struct kernel_shmid64_ds shmctl_arg_t;
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#endif
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static int
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shmctl_syscall (int shmid, int cmd, shmctl_arg_t *buf)
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{
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#ifdef __ASSUME_DIRECT_SYSVIPC_SYSCALLS
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return INLINE_SYSCALL_CALL (shmctl, shmid, cmd | __IPC_64, buf);
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#else
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return INLINE_SYSCALL_CALL (ipc, IPCOP_shmctl, shmid, cmd | __IPC_64, 0,
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buf);
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#endif
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}
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/* Provide operations to control over shared memory segments. */
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int
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__shmctl64 (int shmid, int cmd, struct __shmid64_ds *buf)
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{
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#if __IPC_TIME64
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struct kernel_shmid64_ds kshmid, *arg = NULL;
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if (buf != NULL)
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{
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shmid64_to_kshmid64 (buf, &kshmid);
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arg = &kshmid;
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}
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# ifdef __ASSUME_SYSVIPC_BROKEN_MODE_T
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if (cmd == IPC_SET)
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arg->shm_perm.mode *= 0x10000U;
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# endif
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#else
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shmctl_arg_t *arg = buf;
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#endif
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int ret = shmctl_syscall (shmid, cmd, arg);
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if (ret < 0)
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return ret;
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switch (cmd)
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{
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case IPC_INFO:
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case IPC_STAT:
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case SHM_STAT:
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case SHM_STAT_ANY:
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#ifdef __ASSUME_SYSVIPC_BROKEN_MODE_T
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arg->shm_perm.mode >>= 16;
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#else
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/* Old Linux kernel versions might not clear the mode padding. */
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if (sizeof ((struct shmid_ds){0}.shm_perm.mode)
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!= sizeof (__kernel_mode_t))
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arg->shm_perm.mode &= 0xFFFF;
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#endif
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#if __IPC_TIME64
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kshmid64_to_shmid64 (arg, buf);
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#endif
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}
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return ret;
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}
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#if __TIMESIZE != 64
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libc_hidden_def (__shmctl64)
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static void
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shmid_to_shmid64 (struct __shmid64_ds *shm64, const struct shmid_ds *shm)
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{
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shm64->shm_perm = shm->shm_perm;
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shm64->shm_segsz = shm->shm_segsz;
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shm64->shm_atime = shm->shm_atime
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| ((__time64_t) shm->__shm_atime_high << 32);
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shm64->shm_dtime = shm->shm_dtime
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| ((__time64_t) shm->__shm_dtime_high << 32);
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shm64->shm_ctime = shm->shm_ctime
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| ((__time64_t) shm->__shm_ctime_high << 32);
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shm64->shm_cpid = shm->shm_cpid;
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shm64->shm_lpid = shm->shm_lpid;
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shm64->shm_nattch = shm->shm_nattch;
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}
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static void
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shmid64_to_shmid (struct shmid_ds *shm, const struct __shmid64_ds *shm64)
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{
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shm->shm_perm = shm64->shm_perm;
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shm->shm_segsz = shm64->shm_segsz;
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shm->shm_atime = shm64->shm_atime;
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shm->__shm_atime_high = 0;
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shm->shm_dtime = shm64->shm_dtime;
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shm->__shm_dtime_high = 0;
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shm->shm_ctime = shm64->shm_ctime;
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shm->__shm_ctime_high = 0;
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shm->shm_cpid = shm64->shm_cpid;
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shm->shm_lpid = shm64->shm_lpid;
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shm->shm_nattch = shm64->shm_nattch;
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}
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int
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__shmctl (int shmid, int cmd, struct shmid_ds *buf)
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{
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struct __shmid64_ds shmid64, *buf64 = NULL;
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if (buf != NULL)
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{
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shmid_to_shmid64 (&shmid64, buf);
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buf64 = &shmid64;
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}
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int ret = __shmctl64 (shmid, cmd, buf64);
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if (ret < 0)
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return ret;
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switch (cmd)
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{
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case IPC_INFO:
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case IPC_STAT:
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case SHM_STAT:
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case SHM_STAT_ANY:
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shmid64_to_shmid (buf, buf64);
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}
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return ret;
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}
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#endif
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#ifndef DEFAULT_VERSION
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# ifndef __ASSUME_SYSVIPC_BROKEN_MODE_T
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# define DEFAULT_VERSION GLIBC_2_2
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# else
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# define DEFAULT_VERSION GLIBC_2_31
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# endif
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#endif
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versioned_symbol (libc, __shmctl, shmctl, DEFAULT_VERSION);
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#if defined __ASSUME_SYSVIPC_BROKEN_MODE_T \
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&& SHLIB_COMPAT (libc, GLIBC_2_2, GLIBC_2_31)
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int
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attribute_compat_text_section
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__shmctl_mode16 (int shmid, int cmd, struct shmid_ds *buf)
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{
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return shmctl_syscall (shmid, cmd, (shmctl_arg_t *) buf);
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}
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compat_symbol (libc, __shmctl_mode16, shmctl, GLIBC_2_2);
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#endif
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#if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_2)
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struct __old_shmid_ds
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{
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struct __old_ipc_perm shm_perm; /* operation permission struct */
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int shm_segsz; /* size of segment in bytes */
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__time_t shm_atime; /* time of last shmat() */
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__time_t shm_dtime; /* time of last shmdt() */
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__time_t shm_ctime; /* time of last change by shmctl() */
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__ipc_pid_t shm_cpid; /* pid of creator */
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__ipc_pid_t shm_lpid; /* pid of last shmop */
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unsigned short int shm_nattch; /* number of current attaches */
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unsigned short int __shm_npages; /* size of segment (pages) */
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unsigned long int *__shm_pages; /* array of ptrs to frames -> SHMMAX */
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struct vm_area_struct *__attaches; /* descriptors for attaches */
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};
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int
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attribute_compat_text_section
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__old_shmctl (int shmid, int cmd, struct __old_shmid_ds *buf)
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{
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#if defined __ASSUME_DIRECT_SYSVIPC_SYSCALLS \
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&& !defined __ASSUME_SYSVIPC_DEFAULT_IPC_64
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/* For architecture that have wire-up shmctl but also have __IPC_64 to a
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value different than default (0x0), it means the compat symbol used the
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__NR_ipc syscall. */
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return INLINE_SYSCALL_CALL (shmctl, shmid, cmd, buf);
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#else
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return INLINE_SYSCALL_CALL (ipc, IPCOP_shmctl, shmid, cmd, 0, buf);
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#endif
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}
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compat_symbol (libc, __old_shmctl, shmctl, GLIBC_2_0);
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#endif
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