glibc/sysdeps/unix/sysv/linux/include/sys/shm.h

#ifndef _SYS_SHM_H
#include <sysvipc/sys/shm.h>

#ifndef _ISOMAC

# if __TIMESIZE == 64
#  define __shmctl64 __shmctl
# else
extern int __shmctl64 (int shmid, int cmd, struct __shmid64_ds *buf);
libc_hidden_proto (__shmctl64);
# endif

#endif /* _ISOMAC  */

#endif /* _SYS_SHM_H  */
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			`#ifndef _SYS_SHM_H`
			`#include <sysvipc/sys/shm.h>`

			`#ifndef _ISOMAC`

			`# if __TIMESIZE == 64`
			`# define __shmctl64 __shmctl`
			`# else`
			`extern int __shmctl64 (int shmid, int cmd, struct __shmid64_ds *buf);`
			`libc_hidden_proto (__shmctl64);`
			`# endif`

			`#endif /* _ISOMAC */`

			`#endif /* _SYS_SHM_H */`