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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>
378 lines
9.5 KiB
C
378 lines
9.5 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/sem.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 <bits/types/struct_semid64_ds.h> /* For __semid64_ds. */
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#include <linux/posix_types.h> /* For __kernel_mode_t. */
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/* The struct used to issue the syscall. For architectures that assume
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64-bit time as default (!__ASSUME_TIME64_SYSCALLS) the syscall will
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split the resulting 64-bit sem_{o,c}time in two fields (sem_{o,c}time
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and __sem_{o,c}time_high). */
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union semun
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{
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int val; /* value for SETVAL */
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struct semid_ds *buf; /* buffer for IPC_STAT & IPC_SET */
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unsigned short int *array; /* array for GETALL & SETALL */
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struct seminfo *__buf; /* buffer for IPC_INFO */
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};
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#if __IPC_TIME64 == 0
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# define semun64 semun
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typedef union semun semctl_arg_t;
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#else
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# include <struct_kernel_semid64_ds.h>
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union ksemun64
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{
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int val;
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struct kernel_semid64_ds *buf;
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unsigned short int *array;
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struct seminfo *__buf;
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};
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# if __TIMESIZE == 64
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# define semun64 semun
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# else
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/* The struct used when __semctl64 is called. */
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union semun64
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{
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int val;
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struct __semid64_ds *buf;
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unsigned short int *array;
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struct seminfo *__buf;
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};
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# endif
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static void
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semid64_to_ksemid64 (const struct __semid64_ds *semid64,
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struct kernel_semid64_ds *ksemid)
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{
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ksemid->sem_perm = semid64->sem_perm;
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ksemid->sem_otime = semid64->sem_otime;
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ksemid->sem_otime_high = semid64->sem_otime >> 32;
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ksemid->sem_ctime = semid64->sem_ctime;
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ksemid->sem_ctime_high = semid64->sem_ctime >> 32;
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ksemid->sem_nsems = semid64->sem_nsems;
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}
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static void
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ksemid64_to_semid64 (const struct kernel_semid64_ds *ksemid,
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struct __semid64_ds *semid64)
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{
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semid64->sem_perm = ksemid->sem_perm;
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semid64->sem_otime = ksemid->sem_otime
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| ((__time64_t) ksemid->sem_otime_high << 32);
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semid64->sem_ctime = ksemid->sem_ctime
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| ((__time64_t) ksemid->sem_ctime_high << 32);
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semid64->sem_nsems = ksemid->sem_nsems;
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}
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static union ksemun64
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semun64_to_ksemun64 (int cmd, union semun64 semun64,
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struct kernel_semid64_ds *buf)
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{
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union ksemun64 r = { 0 };
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switch (cmd)
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{
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case SETVAL:
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r.val = semun64.val;
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break;
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case GETALL:
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case SETALL:
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r.array = semun64.array;
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break;
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case SEM_STAT:
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case IPC_STAT:
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case IPC_SET:
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r.buf = buf;
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semid64_to_ksemid64 (semun64.buf, r.buf);
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break;
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case IPC_INFO:
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case SEM_INFO:
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r.__buf = semun64.__buf;
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break;
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}
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return r;
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}
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typedef union ksemun64 semctl_arg_t;
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#endif
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static int
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semctl_syscall (int semid, int semnum, int cmd, semctl_arg_t arg)
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{
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#ifdef __ASSUME_DIRECT_SYSVIPC_SYSCALLS
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return INLINE_SYSCALL_CALL (semctl, semid, semnum, cmd | __IPC_64,
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arg.array);
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#else
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return INLINE_SYSCALL_CALL (ipc, IPCOP_semctl, semid, semnum, cmd | __IPC_64,
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SEMCTL_ARG_ADDRESS (arg));
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#endif
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}
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/* POSIX states ipc_perm mode should have type of mode_t. */
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_Static_assert (sizeof ((struct semid_ds){0}.sem_perm.mode)
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== sizeof (mode_t),
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"sizeof (msqid_ds.msg_perm.mode) != sizeof (mode_t)");
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int
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__semctl64 (int semid, int semnum, int cmd, ...)
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{
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union semun64 arg64 = { 0 };
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va_list ap;
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/* Get the argument only if required. */
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switch (cmd)
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{
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case SETVAL: /* arg.val */
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case GETALL: /* arg.array */
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case SETALL:
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case IPC_STAT: /* arg.buf */
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case IPC_SET:
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case SEM_STAT:
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case IPC_INFO: /* arg.__buf */
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case SEM_INFO:
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va_start (ap, cmd);
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arg64 = va_arg (ap, union semun64);
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va_end (ap);
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break;
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}
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#if __IPC_TIME64
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struct kernel_semid64_ds ksemid;
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union ksemun64 ksemun = semun64_to_ksemun64 (cmd, arg64, &ksemid);
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# ifdef __ASSUME_SYSVIPC_BROKEN_MODE_T
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if (cmd == IPC_SET)
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ksemid.sem_perm.mode *= 0x10000U;
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# endif
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union ksemun64 arg = ksemun;
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#else
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union semun arg = arg64;
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#endif
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int ret = semctl_syscall (semid, semnum, 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_STAT:
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case SEM_STAT:
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case SEM_STAT_ANY:
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#ifdef __ASSUME_SYSVIPC_BROKEN_MODE_T
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arg.buf->sem_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 semid_ds){0}.sem_perm.mode)
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!= sizeof (__kernel_mode_t))
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arg.buf->sem_perm.mode &= 0xFFFF;
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#endif
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#if __IPC_TIME64
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ksemid64_to_semid64 (arg.buf, arg64.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 (__semctl64)
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/* The 64-bit time_t semid_ds version might have a different layout and
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internal field alignment. */
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static void
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semid_to_semid64 (struct __semid64_ds *ds64, const struct semid_ds *ds)
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{
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ds64->sem_perm = ds->sem_perm;
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ds64->sem_otime = ds->sem_otime
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| ((__time64_t) ds->__sem_otime_high << 32);
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ds64->sem_ctime = ds->sem_ctime
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| ((__time64_t) ds->__sem_ctime_high << 32);
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ds64->sem_nsems = ds->sem_nsems;
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}
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static void
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semid64_to_semid (struct semid_ds *ds, const struct __semid64_ds *ds64)
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{
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ds->sem_perm = ds64->sem_perm;
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ds->sem_otime = ds64->sem_otime;
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ds->__sem_otime_high = 0;
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ds->sem_ctime = ds64->sem_ctime;
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ds->__sem_ctime_high = 0;
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ds->sem_nsems = ds64->sem_nsems;
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}
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static union semun64
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semun_to_semun64 (int cmd, union semun semun, struct __semid64_ds *semid64)
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{
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union semun64 r = { 0 };
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switch (cmd)
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{
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case SETVAL:
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r.val = semun.val;
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break;
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case GETALL:
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case SETALL:
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r.array = semun.array;
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break;
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case SEM_STAT:
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case IPC_STAT:
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case IPC_SET:
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r.buf = semid64;
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semid_to_semid64 (r.buf, semun.buf);
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break;
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case IPC_INFO:
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case SEM_INFO:
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r.__buf = semun.__buf;
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break;
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}
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return r;
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}
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int
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__semctl (int semid, int semnum, int cmd, ...)
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{
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union semun arg = { 0 };
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va_list ap;
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/* Get the argument only if required. */
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switch (cmd)
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{
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case SETVAL: /* arg.val */
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case GETALL: /* arg.array */
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case SETALL:
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case IPC_STAT: /* arg.buf */
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case IPC_SET:
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case SEM_STAT:
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case IPC_INFO: /* arg.__buf */
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case SEM_INFO:
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va_start (ap, cmd);
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arg = va_arg (ap, union semun);
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va_end (ap);
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break;
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}
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struct __semid64_ds semid64;
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union semun64 arg64 = semun_to_semun64 (cmd, arg, &semid64);
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int ret = __semctl64 (semid, semnum, cmd, arg64);
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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_STAT:
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case SEM_STAT:
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case SEM_STAT_ANY:
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semid64_to_semid (arg.buf, arg64.buf);
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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, __semctl, semctl, 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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__semctl_mode16 (int semid, int semnum, int cmd, ...)
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{
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semctl_arg_t arg = { 0 };
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va_list ap;
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/* Get the argument only if required. */
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switch (cmd)
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{
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case SETVAL: /* arg.val */
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case GETALL: /* arg.array */
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case SETALL:
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case IPC_STAT: /* arg.buf */
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case IPC_SET:
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case SEM_STAT:
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case IPC_INFO: /* arg.__buf */
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case SEM_INFO:
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va_start (ap, cmd);
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arg = va_arg (ap, semctl_arg_t);
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va_end (ap);
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break;
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}
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return semctl_syscall (semid, semnum, cmd, arg);
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}
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compat_symbol (libc, __semctl_mode16, semctl, 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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/* Since semctl use a variadic argument for semid_ds there is not need to
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define and tie the compatibility symbol to the old 'union semun'
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definition. */
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int
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attribute_compat_text_section
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__old_semctl (int semid, int semnum, int cmd, ...)
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{
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union semun arg = { 0 };
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va_list ap;
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/* Get the argument only if required. */
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switch (cmd)
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{
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case SETVAL: /* arg.val */
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case GETALL: /* arg.array */
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case SETALL:
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case IPC_STAT: /* arg.buf */
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case IPC_SET:
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case SEM_STAT:
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case IPC_INFO: /* arg.__buf */
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case SEM_INFO:
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va_start (ap, cmd);
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arg = va_arg (ap, union semun);
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va_end (ap);
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break;
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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 architectures that have wire-up semctl 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 (semctl, semid, semnum, cmd, arg.array);
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# else
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return INLINE_SYSCALL_CALL (ipc, IPCOP_semctl, semid, semnum, cmd,
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SEMCTL_ARG_ADDRESS (arg));
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# endif
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}
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compat_symbol (libc, __old_semctl, semctl, GLIBC_2_0);
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#endif
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