glibc/sysdeps/unix/sysv/linux/struct_kernel_shmid64_ds.h

/* Analogous to kernel struct shmid64_ds used on shmctl.  */
struct kernel_shmid64_ds
{
  struct ipc_perm shm_perm;
  size_t shm_segsz;
  unsigned long int shm_atime;
  unsigned long int shm_atime_high;
  unsigned long int shm_dtime;
  unsigned long int shm_dtime_high;
  unsigned long int shm_ctime;
  unsigned long int shm_ctime_high;
  __pid_t shm_cpid;
  __pid_t shm_lpid;
  unsigned long int shm_nattch;
  unsigned long int __unused1;
  unsigned long int __unused2;
};
sysv: linux: Add 64-bit time_t variant for shmctl 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> 2020-06-30 17:08:22 +00:00			`/* Analogous to kernel struct shmid64_ds used on shmctl. */`
			`struct kernel_shmid64_ds`
			`{`
			`struct ipc_perm shm_perm;`
			`size_t shm_segsz;`
			`unsigned long int shm_atime;`
			`unsigned long int shm_atime_high;`
			`unsigned long int shm_dtime;`
			`unsigned long int shm_dtime_high;`
			`unsigned long int shm_ctime;`
			`unsigned long int shm_ctime_high;`
			`__pid_t shm_cpid;`
			`__pid_t shm_lpid;`
			`unsigned long int shm_nattch;`
			`unsigned long int __unused1;`
			`unsigned long int __unused2;`
			`};`