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.
__ASSUME_COMPLETE_READV_WRITEV.
* sysdeps/unix/sysv/linux/readv.c: No need for userlevel fallback
with modern kernels.
* sysdeps/unix/sysv/linux/writev.c: Likewise.
* sysdeps/posix/readv.c: Since read is a cancellation point we have
to free a possible malloced buffer in case of cancellation.
* sysdeps/posix/writev.c: Likewise for write.
c2009-04-01 Ulrich Drepper <drepper@redhat.com>
