In <https://sourceware.org/ml/libc-alpha/2013-12/msg00008.html>,
Aurelien noted issues with the definition of __ASSUME_ACCEPT4, which I
discussed in more detail in
<https://sourceware.org/ml/libc-alpha/2013-12/msg00014.html>; these
are now bug 16609.
As previously noted, __ASSUME_ACCEPT4 is used in two ways:
* In OS-independent code, to mean "accept4 can be assumed to work
rather than fail with ENOSYS". It doesn't matter whether it's
implemented with socketcall or a separate syscall.
* In Linux-specific code, to mean "the socketcall multiplex syscall
can be assumed to handle the accept4 operation. When used in
Linux-specific code, it *never* refers to anything relating to the
accept4 syscall, only to the socketcall multiplexer.
This patch splits the macro into separate __ASSUME_ACCEPT4_SOCKETCALL,
__ASSUME_ACCEPT4_SYSCALL and __ASSUME_ACCEPT4 to clarify the different
cases involved. A macro __ASSUME_SOCKETCALL is added for convenience
in writing logic relating to all socketcall architectures. In
addition, to address the issue of architectures where socketcall
support for accept4 was added before a separate syscall was added (and
so the separate syscall should not be used unless known to be present
or fallback to socketcall is available), a fourth macro
__ASSUME_ACCEPT4_SYSCALL_WITH_SOCKETCALL is added to indicate that the
syscall became available at the same time as socketcall support. This
is then used in the relevant places in a conditional determining
whether to undefine __NR_accept4 (the simple approach to avoiding the
syscall's presence causing problems; I didn't try to implement runtime
fallback from the syscall to socketcall).
Architecture-specific note: alpha defined __ASSUME_ACCEPT4 for 2.6.33
and later, but actually the syscall was added for alpha in 3.2, so
this patch uses the correct condition for __ASSUME_ACCEPT4_SYSCALL
there.
Tested x86_64, including that disassembly of the installed shared
libraries is unchanged by this patch.
[BZ #16609]
* sysdeps/unix/sysv/linux/kernel-features.h [__i386__ ||
__powerpc__ || __s390__ || __sh__ || __sparc__]
(__ASSUME_SOCKETCALL): Define.
[__LINUX_KERNEL_VERSION && __ASSUME_SOCKETCALL]
(__ASSUME_ACCEPT4_SOCKETCALL): Likewise.
[(__LINUX_KERNEL_VERSION >= 0x02061c && (__x86_64__ || __sparc__))
|| (__LINUX_KERNEL_VERSION >= 0x020625 && (__powerpc__ ||
__sh__))] (__ASSUME_ACCEPT4_SYSCALL): Likewise.
[__sparc__] (__ASSUME_ACCEPT4_SYSCALL_WITH_SOCKETCALL): Likewise.
[__ASSUME_ACCEPT4_SOCKETCALL || __ASSUME_ACCEPT4_SYSCALL]
(__ASSUME_ACCEPT4): Define instead of using previous
[__LINUX_KERNEL_VERSION >= 0x02061c && (__i386__ || __x86_64__ ||
__powerpc__ || __sparc__ || __s390__)] condition.
* sysdeps/unix/sysv/linux/aarch64/kernel-features.h
(__ASSUME_ACCEPT4): Change to __ASSUME_ACCEPT4_SYSCALL.
* sysdeps/unix/sysv/linux/accept4.c [__ASSUME_SOCKETCALL &&
!__ASSUME_ACCEPT4_SYSCALL_WITH_SOCKETCALL &&
!__ASSUME_ACCEPT4_SYSCALL] (__NR_accept4): Undefine.
[!__ASSUME_ACCEPT4]: Change condition to
[!__ASSUME_ACCEPT4_SOCKETCALL].
* sysdeps/unix/sysv/linux/alpha/kernel-features.h
(__ASSUME_ACCEPT4): Change to __ASSUME_ACCEPT4_SYSCALL. Correct
condition to [__LINUX_KERNEL_VERSION >= 0x030200].
* sysdeps/unix/sysv/linux/arm/kernel-features.h
[__LINUX_KERNEL_VERSION >= 0x020624] (__ASSUME_ACCEPT4): Change to
__ASSUME_ACCEPT4_SYSCALL.
* sysdeps/unix/sysv/linux/i386/accept4.S [__ASSUME_ACCEPT4]:
Change conditions to [__ASSUME_ACCEPT4_SOCKETCALL].
* sysdeps/unix/sysv/linux/ia64/kernel-features.h
[__LINUX_KERNEL_VERSION >= 0x030300] (__ASSUME_ACCEPT4): Change to
__ASSUME_ACCEPT4_SYSCALL.
* sysdeps/unix/sysv/linux/internal_accept4.S [__ASSUME_SOCKETCALL
&& !__ASSUME_ACCEPT4_SYSCALL_WITH_SOCKETCALL &&
!__ASSUME_ACCEPT4_SYSCALL] (__NR_accept4): Undefine.
[__ASSUME_ACCEPT4]: Change condition to
[__ASSUME_ACCEPT4_SOCKETCALL].
* sysdeps/unix/sysv/linux/m68k/kernel-features.h
(__ASSUME_SOCKETCALL): Define.
[__LINUX_KERNEL_VERSION >= 0x02061c] (__ASSUME_ACCEPT4): Remove.
* sysdeps/unix/sysv/linux/microblaze/kernel-features.h
(__ASSUME_SOCKETCALL): Define.
(__ASSUME_ACCEPT4): Remove.
[__LINUX_KERNEL_VERSION >= 0x020621] (__ASSUME_ACCEPT4_SYSCALL):
Define.
* sysdeps/unix/sysv/linux/mips/kernel-features.h
[__LINUX_KERNEL_VERSION >= 0x02061f] (__ASSUME_ACCEPT4_SYSCALL):
Likewise.
* sysdeps/unix/sysv/linux/tile/kernel-features.h
(__ASSUME_ACCEPT4): Change to __ASSUME_ACCEPT4_SYSCALL.
* sysdeps/unix/sysv/linux/hppa/kernel-features.h
[__LINUX_KERNEL_VERSION >= 0x020622] (__ASSUME_ACCEPT4_SYSCALL):
Define.
Support for /proc/self/task/$tid/comm as added in Linux 2.6.33,
therefore since the test tst-setgetname relies on this functionality
to operate we must skip the test in kernels < 2.6.33. We wrap the
checks with __ASSUME_PROC_PID_TASK_COMM such that in the future when
we move arch_minimum_kernel to 2.6.33 we can remove this code.
Fix BZ #15305.
On kernel versions earlier than 2.6.29, the Linux kernel exported a
sysctl called restrict_chown for xfs, which could be used to allow
chown to users other than the owner. 2.6.29 removed this support,
causing the open_not_cancel_2 to fail and thus modify errno. The fix
is to save and restore errno so that the caller sees it as unmodified.
Additionally, since the code to check the sysctl is not useful on
newer kernels, we add an ifdef so that in future the code block gets
rmeoved completely.
* sysdeps/unix/sysv/linux/kernel-features.h
(__ASSUME_CLONE_THREAD_FLAGS): Set on sparc when 2.5.64 and later.
(__ASSUME_TGKILL): Set on sparc when 2.6.1 and later, simplify
expression.
(__ASSUME_FADVISE64_64_SYSCALL): Set on sparc when 2.6.1 and
later.
fopen should set the FD_CLOEXEC flag if requested evenif the kernel does
not support an aotmic operation.
freopen should reuse the file descriptor for the stream. This is
especially important for calls to change the standard streams (stin,
stdout, stderr).
The syscall conventions on some Linux archs prevented F_GETOWN from working
correctly in some situations. This can be rectified when using the new
F_GETOWN_EX command.
* misc/Versions: Export preadv, preadv64, pwritev, pwritev64 for
GLIBC_2.10.
* misc/sys/uio.h: Declare preadv, preadv64, pwritev, pwritev64.
* sysdeps/unix/sysv/linux/kernel-features.h: Add entries for preadv
and pwritev.
* misc/preadv.c: New file.
* misc/preadv64.c: New file.
* misc/pwritev.c: New file.
* misc/pwritev64.c: New file.
* sysdeps/posx/preadv.c: New file.
* sysdeps/posx/preadv64.c: New file.
* sysdeps/posx/pwritev.c: New file.
* sysdeps/posx/pwritev64.c: New file.
* sysdeps/unix/sysv/linux/preadv.c: New file.
* sysdeps/unix/sysv/linux/preadv64.c: New file.
* sysdeps/unix/sysv/linux/pwritev.c: New file.
* sysdeps/unix/sysv/linux/pwritev64.c: New file.
* sysdeps/unix/sysv/linux/wordsize-64/preadv64.c: New file.
* sysdeps/unix/sysv/linux/wordsize-64/pwritev64.c: New file.