Since Linux kernel 3.12, tcp_syncookies can have the value 2,
which sends out cookies unconditionally.
Related kernel commits:
5ad37d5deee1ff7150a2d0602370101de158ad86
d8513df2598e5142f8a5c4724f28411936e1dfc7
Reported-by: Philip Rowlands <linux-kernel@dimebar.com>
Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Hannes Frederic Sowa <hannes@stressinduktion.org>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Quoting Heinrich:
The strnlen.3 manpage has the following sentence:
"In doing this, strnlen() looks only at the first maxlen
characters in the string pointed to by s and never beyond
s+maxlen."
This sentence is self-contradictory:
The last visited character implied by "first maxlen
characters" is s[maxlen-1].
Given that "beyond a" does not include "a", the last visited
character implied by "never beyond s+maxlen" is s[maxlen].
A consistent sentence would be
"In doing this, strnlen() looks only at the first maxlen
characters in the string pointed to by s and never beyond
s+maxlen-1."
I would prefer
"In doing this, strnlen() looks only at the first maxlen
characters in the string pointed to by s and never beyond
s[maxlen-1]"
Reported-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
The Linux kernel uses 'int' instead of 'long' for the return type.
As glibc provides no wrapper, use the same type the kernel uses.
......
$ grep -n wrapper man-pages/man2/subpage_prot.2
40:There is no glibc wrapper for this system call; see NOTES.
99:Glibc does not provide a wrapper for this system call; call it using
$ grep -rn SYSCALL_DEFINE.*subpage_prot linux/;
linux/arch/powerpc/mm/book3s64/subpage_prot.c:190:
SYSCALL_DEFINE3(subpage_prot, unsigned long, addr,
$ sed -n /SYSCALL.*subpage_prot/,/^}/p \
linux/arch/powerpc/mm/book3s64/subpage_prot.c \
|grep return;
return -ENOENT;
return -EINVAL;
return -EINVAL;
return 0;
return -EFAULT;
return -EFAULT;
return err;
$ sed -n /SYSCALL.*subpage_prot/,/^}/p \
linux/arch/powerpc/mm/book3s64/subpage_prot.c \
|grep '\<err\>';
int err;
err = -ENOMEM;
err = -ENOMEM;
err = 0;
return err;
Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
This paragraph is a little bit hidden at the end of DESCRIPTION;
make it a little more prominent.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Linux kernel commit aae8a97d3ec30788790d1720b71d76fd8eb44b73 (part
of kernel release v2.6.39) added a check to disallow creating a
hardlink to an unlinked file.
The manual page already describes the trick of using
AT_SYMLINK_FOLLOW as an alternative to AT_EMPTY_PATH, and for
AT_EMPTY_PATH the manual page already notes that it "will
generally not work if the file has a link count of zero". However,
the precise error (ENOENT) is not mentioned, and the error case
isn't mentioned in the ERRORS section at all.
This makes it easy to overlook the fact that the AT_SYMLINK_FOLLOW
trick on /proc/self/fd/NN won't work on deleted files, as
evidenced by the follow message (which turns up when googling
"linkat deleted ENOENT"):
https://groups.google.com/g/linux.kernel/c/zZO4lqqwp64
Signed-off-by: Mathias Rav <m@git.strova.dk>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
The Linux kernel uses 'pid_t' instead of 'long' for the return type.
As glibc provides no wrapper, use the same types the kernel uses.
$ sed -n 34,36p man-pages/man2/set_tid_address.2
.PP
.IR Note :
There is no glibc wrapper for this system call; see NOTES.
$ grep -rn 'SYSCALL_DEFINE.*set_tid_address' linux/
linux/kernel/fork.c:1632:
SYSCALL_DEFINE1(set_tid_address, int __user *, tidptr)
$ sed -n 1632,1638p linux/kernel/fork.c
SYSCALL_DEFINE1(set_tid_address, int __user *, tidptr)
{
current->clear_child_tid = tidptr;
return task_pid_vnr(current);
}
$ grep -rn 'task_pid_vnr(struct' linux/
linux/include/linux/sched.h:1374:
static inline pid_t task_pid_vnr(struct task_struct *tsk)
Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Learned from an email converasation with Mike Crowe, and
verified by experiment.
Reported-by: Mike Crowe <mac@mcrowe.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
As far as I can see, it is instead simply an alias for a
wrapper that calls _llseek(). Saying it's an alias for "llseek()"
seems confusing.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
We're talking of a mix of wrapper functions and system calls
in this page. lseek() is both a system and a wrapper function,
and this page is mostly describing the wrapper
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
{.IR var [x]} -> {.I var[x]}
There were around 15 entries of the former,
and around 360 of the latter.
Found using:
$ grep -rn '^\.I[ |R].* \[.*\]' |sort
Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Found using:
$ grep -rn '\\f., [^ ]*\\f. and' man?
I also updated the markup in that paragraph: \f -> .
Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
In the comment of the example program, the peer blocks on fwait()
rather than fpost().
Signed-off-by: Jing Peng <pj.hades@gmail.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Rather than mention these pages under the discussion of one
version of the standard, move that text to the end of the page,
where it is probably a little more obvious.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Michael Kerrisk