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Different than others 64-bit time_t syscalls, the SysIPC interface
does not provide a new set of syscall for y2038 safeness. Instead it
uses unused fields in semid_ds structure to return the high bits for
the timestamps.
To provide a y2038 safe interface a new symbol __semctl64 is added
and __semctl 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_semid64_ds: used internally only on 32-bit architectures
to issue the syscall. A handful of architectures (hppa, i386,
mips, powerpc32, sparc32) require specific implementations due
their kernel ABI.
2. semid_ds64: this is only for __TIMESIZE != 64 to use along with
the 64-bit semctl. 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 semid_ds already contains
64-bit time_t fields and will result in just the __semctl symbol
using the __semctl64 code. The semid_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 handling.
It might be possible to optimize it further to avoid the
kernel_semid64_ds to semun transformation if the exported ABI
for the architectures matches the expected kernel ABI, but the
implementation is already complex enough and don't think this
should be a hotspot in any case.
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 the 64-bit one.
The default 32-bit symbol will allocate and copy the semid_ds
over multiple buffers, but this should be deprecated in favor
of the __semctl64 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: Vineet Gupta <vgupta@synopsys.com>
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
67 lines
2.3 KiB
C
67 lines
2.3 KiB
C
/* Old SysV permission definition for Linux. Default version.
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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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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/ipc.h> /* For __key_t */
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#include <kernel-features.h>
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#ifdef __ASSUME_SYSVIPC_DEFAULT_IPC_64
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# define __IPC_64 0x0
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#else
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# define __IPC_64 0x100
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#endif
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#ifndef __OLD_IPC_ID_TYPE
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# define __OLD_IPC_ID_TYPE unsigned short int
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#endif
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#ifndef __OLD_IPC_MODE_TYPE
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# define __OLD_IPC_MODE_TYPE unsigned short int
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#endif
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struct __old_ipc_perm
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{
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__key_t __key; /* Key. */
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__OLD_IPC_ID_TYPE uid; /* Owner's user ID. */
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__OLD_IPC_ID_TYPE gid; /* Owner's group ID. */
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__OLD_IPC_ID_TYPE cuid; /* Creator's user ID. */
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__OLD_IPC_ID_TYPE cgid; /* Creator's group ID. */
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__OLD_IPC_MODE_TYPE mode; /* Read/write permission. */
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unsigned short int __seq; /* Sequence number. */
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};
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#define SEMCTL_ARG_ADDRESS(__arg) &__arg.array
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#define MSGRCV_ARGS(__msgp, __msgtyp) \
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((long int []){ (long int) __msgp, __msgtyp })
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/* This macro is required to handle the s390 variants, which passes the
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arguments in a different order than default. */
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#define SEMTIMEDOP_IPC_ARGS(__nsops, __sops, __timeout) \
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(__nsops), 0, (__sops), (__timeout)
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/* Linux SysV ipc does not provide new syscalls for 64-bit time support on
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32-bit architectures, but rather split the timestamp into high and low;
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storing the high value in previously unused fields. */
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#if (__WORDSIZE == 32 \
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&& (!defined __SYSCALL_WORDSIZE || __SYSCALL_WORDSIZE == 32))
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# define __IPC_TIME64 1
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#else
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# define __IPC_TIME64 0
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#endif
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#include <ipc_ops.h>
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