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dba950e317
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>
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| .. | ||
| auxv.h | ||
| bitypes.h | ||
| cdefs.h | ||
| dir.h | ||
| epoll.h | ||
| errno.h | ||
| fcntl.h | ||
| file.h | ||
| gmon_out.h | ||
| gmon.h | ||
| ioctl.h | ||
| ipc.h | ||
| mman.h | ||
| msg.h | ||
| param.h | ||
| poll.h | ||
| prctl.h | ||
| profil.h | ||
| queue.h | ||
| random.h | ||
| resource.h | ||
| select.h | ||
| sem.h | ||
| sendfile.h | ||
| shm.h | ||
| signal.h | ||
| single_threaded.h | ||
| socket.h | ||
| stat.h | ||
| statfs.h | ||
| statvfs.h | ||
| sysinfo.h | ||
| syslog.h | ||
| sysmacros.h | ||
| termios.h | ||
| time.h | ||
| timeb.h | ||
| times.h | ||
| ttychars.h | ||
| types.h | ||
| uio.h | ||
| un.h | ||
| unistd.h | ||
| utsname.h | ||
| vfs.h | ||
| vlimit.h | ||
| vtimes.h | ||
| wait.h | ||
| xattr.h | ||