glibc/sysdeps/unix/sysv/linux/generic
Joseph Myers 5f45f96ad0 Unify umount function implementations (bug 16552).
Linux kernel architectures have various arrangements for umount
syscalls.  There is a syscall that takes flags, and an older one that
does not.  Newer architectures have only the one taking flags, under
the name umount2 (or under the name umount, in the ia64 case).  Older
architectures may have both, under the names umount2 and umount (or
under the names umount and oldumount, in the alpha case).  glibc then
has several similar implementations of the umount function (no flags)
in terms of either the __umount2 function, or the corresponding
syscall, or in terms of the old syscall under either of its names.

This patch simplifies the implementations in glibc by always using the
__umount2 function to implement the umount function on all systems
using the Linux kernel.  The linux/generic implementation is moved to
sysdeps/unix/sysv/linux (without any changes to code or comments) and
all the other variants are removed.  (This will have the effect of
causing the new syscall to be used in some cases that previously used
the old one, but as discussed for previous changes, such a change to
the underlying syscalls used is OK.)

There remain two variants of how the __umount2 function is
implemented, either in umount2.S, or, for ia64, in syscalls.list.

Tested with build-many-glibcs.py.

	[BZ #16552]
	* sysdeps/unix/sysv/linux/generic/umount.c: Move to ....
	* sysdeps/unix/sysv/linux/umount.c: ... here.
	* sysdeps/unix/sysv/linux/arm/umount.c: Remove file.
	* sysdeps/unix/sysv/linux/hppa/umount.c: Likewise.
	* sysdeps/unix/sysv/linux/ia64/umount.c: Likewise.
	* sysdeps/unix/sysv/linux/mips/mips64/umount.c: Likewise.
	* sysdeps/unix/sysv/linux/powerpc/powerpc64/umount.c: Likewise.
	* sysdeps/unix/sysv/linux/umount.S: Likewise.
	* sysdeps/unix/sysv/linux/x86_64/umount.c: Likewise.
2018-03-26 21:18:28 +00:00
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futimesat.c Add missing start-of-file descriptive comment. 2018-03-06 09:21:04 +01:00
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getdents.c
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Makefile Consolidate Linux epoll_wait syscall 2017-05-03 10:36:43 -03:00
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This hierarchy supports Linux systems using the new
asm-generic/unistd.h, which removes many familiar old syscalls.  For
example, to implement open(), newer Linux architectures require glibc
to invoke the __NR_openat syscall with AT_FDCWD.  This hierarchy
provides all those implementations.

It also provides support for 32-bit platforms using the 64-bit kernel
syscall APIs, as the 32-bit ones are no longer provided.  Note that
newer ILP32 environments (x32 or AArch64:ILP32, for example) are
converting to use more 64-bit types in kernel syscalls, so that aspect
of this support is in more flux as of this writing.