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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>
19 lines
738 B
C
19 lines
738 B
C
/* Analogous to kernel struct shmid64_ds used on shmctl. */
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struct kernel_shmid64_ds
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{
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struct ipc_perm shm_perm; /* operation permission struct */
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unsigned long int shm_atime_high;
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unsigned long int shm_atime; /* time of last shmat() */
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unsigned long int shm_dtime_high;
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unsigned long int shm_dtime; /* time of last shmdt() */
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unsigned long int shm_ctime_high;
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unsigned long int shm_ctime; /* time of last change by shmctl() */
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unsigned long int __pad;
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size_t shm_segsz; /* size of segment in bytes */
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__pid_t shm_cpid; /* pid of creator */
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__pid_t shm_lpid; /* pid of last shmop */
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shmatt_t shm_nattch; /* number of current attaches */
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unsigned long int __unused1;
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unsigned long int __unused2;
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};
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