mount.2: wfix

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

mount.2: MS_SILENT is ignored when changing propagation type

MS_SILENT can be specified when changing propagation type,
but is ignored, as far as I can see from reading the code.
(The flags are passed to do_change_type(), which, as well
as the propagation flags, allows MS_REC and MS_SILENT
(in flags_to_propagation_type()), but does noting with
MS_SILENT. (Linux 4.17 source)

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

mount.2: wfix

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

mount.2: Minor rewording

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

mount.2: Remove crufty sentence about MS_BIND + MS_REMOUNT

This sentence is left over from an earlier rewrite of the text,
and the relevant details are covered a few paragraphs later.

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

mount.2: srcfix

mount.2: srcfix: update FIXME

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

mount.2: tfix

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

mount.2: SEE ALSO: add ioctl_iflags(2)

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

mount.2: srcfix: add FIXME

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

mount.2: Mandatory locking also now requires CONFIG_MANDATORY_FILE_LOCKING

This is so since Linux 4.5. See the definition of may_mandlock()
in fs/namespace.c.

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

mount.2: ffix

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

mount.2: ffix

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

mount.2: wfix

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

rename.2: Add feature test macro for renameat2()

The glibc wrapper for renameat2() was added in glibc 2.28 and
requires _GNU_SOURCE.

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

proc.5: tfix

Remove duplicated word.

Signed-off-by: Jakub Wilk <jwilk@jwilk.net>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

strcpy.3: Use "destination" consistently (instead of "target" sometimes)

Reported-by: Frank Theile <ftheile@grundfos.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

proc.5: ffix

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

proc.5: Reword /proc/PID/fdinfo timerfd field descriptions as a hanging list

And a few other minor tweaks to the text.

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

proc.5: Add a few details on /rpoc/PID/fdinfo timerfd

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

proc.5: Minor tweaks to Lukas Wermeister's patch

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

proc.5: Document fdinfo format for timerfd

Extended information for timerfd file descriptors in
/proc/[pid]/fdinfo was added in commit af9c4957cf21 ("timerfd:
Implement show_fdinfo method", 2014-07-16), to support
checkpoint/restore for such file descriptors (see also the
TFD_IOC_SET_TICKS ioctl which is documented in timerfd_create.2).

Signed-off-by: Lucas Werkmeister <mail@lucaswerkmeister.de>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

user_namespaces.7: wfix

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

io_submit.2: Minor tweaks to Adam Manzanares' patch

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

io_submit.2: ffix

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

io_submit.2: Document IOCB_FLAG_IOPRIO

The newly added IOCB_FLAG_IOPRIO aio_flag introduces new behaviors
and return values.

The details of this new feature are posted here:
https://lkml.org/lkml/2018/5/22/809

Signed-off-by: Adam Manzanares <adam.manzanares@wdc.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

proc.5: srcfix: rewrap source lines

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

proc.5: Describe ambiguities in /proc/<pid>/maps

Pathname escaping is not done properly in /proc/<pid>/maps;
because of this, different pathnames may appear the same
(verified by experiment and reading the source code).

Further details from Elvira about the relevant location in
the kernel code:

    show_map_vma() from fs/proc/task_mmu.c uses seq_file_path()
    from fs/seq_file.c to print the dentry name, which in turn
    calls seq_path() from the same file.  seq_path() uses
    d_path() from fs/d_path.c to get the path name; this is
    where the " (deleted)" part comes from. This is followed by
    mangling the string with mangle_path() (fs/seq_file.c); this
    function only replaces those characters that were supplied
    in the "esc" argument and does not bother with escaping
    anything else ('\\', for example).  The value of this
    argument comes without modifications from the initial call
    of seq_file_path() by show_map_vma(), and that is "\n".

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

perf_event_open.2: Document the PERF_EVENT_IOC_QUERY_BPF ioctl

The PERF_EVENT_IOC_QUERY_BPF ioctl was introduced in Linux 4.16.

Signed-off-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

perf_event_open.2: wfix

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

perf_event_open.2: Document the PERF_EVENT_IOC_MODIFY_ATTRIBUTES ioctl

The PERF_EVENT_IOC_MODIFY_ATTRIBUTES ioctl was introduced in
Linux 4.17.  It currently only works on breakpoint events.

Signed-off-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

perf_event_open.2: Document the PERF_EVENT_IOC_PAUSE_OUTPUT ioctl

The PERF_EVENT_IOC_PAUSE_OUTPUT ioctl was introduced in Linux 4.7.

I've have this patch for a long time, I apologize for the delay
in getting it submitted.  I've made some minor changes to the
original patch proposed by Wang Nan.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Reviewed-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

perf_event_open.2: Clarify exclude_idle

It turns out no one is really sure what the perf_event_open.2
exclude_idle field is supposed to do, and a recent thread on the
linux-kernel list:
[RFC] perf/core: what is exclude_idle supposed to do
did not really clarify things.

I think the following adjustment to the page clarifies things
at least a little.

Signed-off-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

perf_event_open.2: Fix prctl behavior description

Some discussion on the linux-perf-users list has turned up that
the perf_event_open.2 description of how
PR_TASK_PERF_EVENTS_ENABLE / PR_TASK_PERF_EVENTS_DISABLE prctl()
works is misleading.

The descriptions were based on the tools/perf/design.txt document
which describes behavior that was removed in 082ff5a2767a06 (prior
to 2.6.31, the first release with perf_event_open support).

I have written some tests in my perf_event_tests testsuite that
verifies the behavior of prctl() in this case.

Signed-off-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

namespaces.7: tfix

Signed-off-by: Jakub Wilk <jwilk@jwilk.net>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

bpf.2: srcfix: fix typo in kernel version revied for JIT compiler source

Reported-by: Tobias Klauser <tklauser@distanz.ch>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

bpf.2: Minor tweaks to Tobias Klauser's patch

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

bpf.2: Update JIT support list for Linux 4.18

JIT support for x86-32 was during the Linux 4.18 release cycle.
Also correct the entry for MIPS (only MIPS64 is supported).

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

proc.5: tfix

Reported-by: Stan Schwertly <stan@schwertly.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

vmsplice.2: Minor tweaks to Andrei's patch

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

vmsplice.2: Note that vmsplice can splice pages from pipe to memory

The man page notes that vmsplice() can splice pages from memory
to a pipe, but it can work in the other direction as well.

Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrei Vagin <avagin@openvz.org>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

resolv.conf.5: Document no-reload (RES_NPRELOAD) option

Signed-off-by: Nikola Forró <nforro@redhat.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

namespaces.7: tfix

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

rename.2: renameat2() now has a glibc wrapper; remove mention of syscall(2)

The glibc wrapper was added in glibc 2.28

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

statx.2: statx() now has a glibc wrapper; remove mention of syscall(2)

The glibc wrapper was added in glibc 2.28

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

strcmp.3: tfix

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

strcmp.3: Clarify that strcmp() is not locale aware

Indicate that strcmp() does not take the locale into account.
Provide a link to strcoll().

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

memfd_create.2: Fix header for memfd_create()

sys/memfd.h doesn't exist. memfd_create() is declared in
sys/mman.h and some flags are available only in linux/memfd.h.

Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

string.3, strlen.3, strnlen.3: Use 'bytes' not 'characters'

This is inline with POSIX terminology. See also the earlier
commit a00b7454b8234ff73ac4a78e9059558596b1b788 (in 2012)
which fixed most of these cases.

Reported-by: Jakub Wilk <jwilk@jwilk.net>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

proc.5: Document /proc/[pid]/status Speculation_Store_Bypass field

Signed-off-by: Nikola Forró <nforro@redhat.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

proc.5: ffix

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

proc.5: Correct description of NStgid

The left-most pid namespace in a given procfs' `NStgid` does not
change based on the pid namespace of the reading process. Rather,
each procfs has an associated outer-most namespace, which gets
set when the procfs is mounted:

```
static struct dentry *proc_mount(struct file_system_type *fs_type,
int flags, const char *dev_name, void *data)
{
struct pid_namespace *ns;

if (flags & MS_KERNMOUNT) {
ns = data;
data = NULL;
} else {
ns = task_active_pid_ns(current);
}

return mount_ns(fs_type, flags, data, ns, ns->user_ns, proc_fill_super);
}
```

i.e. either the root namespace for kernel mounts or the namespace
of the mounting process. This ns then gets saved in the fs' super
block and is the basis for most operations. It is this ns that the
left-most value of `NStgid` is relative to, not the reading process.

Reported-by: Robert O'Callahan <robert@ocallahan.org>
Signed-off-by: Keno Fischer <keno@juliacomputing.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

pthread_attr_init.3: Use correct printf() specifier for "size_t" in example program

Reported-by: Göran Häggsjö <goran.haggsjo@icloud.com>
Reported-by: Jakub Wilk <jwilk@jwilk.net>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

sched_yield.2: tfix

Reported-by: Luka Macan <Luka.Macan@fer.hr>
Change "read-time" to "real-time".

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

capabilities.7: tfix

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

uselocale.3: tfix

LC_GLOBAL_HANDLE is not defined anywhere, the doc meant LC_GLOBAL_LOCALE
instead.

Reported-by: Solal Pirelli <solal.pirelli@gmail.com>
Signed-off-by: Antonio Ospite <ao2@ao2.it>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

utmp.5: ffix

Reported-by: Sam Varshavchik <mrsam@courier-mta.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

perf_event_open.2: ffix

Reported-by: Sam Varshavchik <mrsam@courier-mta.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

seccomp.2: ffix

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

posixoptions.7: ffix

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

getmntent.3: srcfix

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

bpf.2: ffix

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

smartpqi.4: ffix

Reported-by: Sam Varshavchik <mrsam@courier-mta.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

perf_event_open.2: tfix

Reported-by: Sam Varshavchik <mrsam@courier-mta.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

getutent.3: tfix

Reported-by: Sam Varshavchik <mrsam@courier-mta.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

getopt.3: ffix

Reported-by: Sam Varshavchik <mrsam@courier-mta.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

namespaces.7: Mention ioctl(2) in discussion of namespaces APIs

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

namespaces.7: List factors that may pin a namespace into existence

Various factors may pin a namespace into existence, even when it
has no member processes.

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

seccomp.2: SEE ALSO: add bpfc(1)

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

unshare.2: Same EINVAL errors as for clone(2) can also occur with unshare(2)

The EINVAL errors that can occur for clone(2) when it is called
with various CLONE_NEW* flags and the kernel was not configured
with support for the corresponding namespace can also occur for
unshare(2).  (As far as I can see, these errors don't occur for
either clone(2) or unshare(2) when it comes to CLONE_NEWNS and
CLONE_NEWCGROUP.)

Reported-by: Shawn Landden <shawn@git.icu>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

clone.2: ERRORS: EINVAL occurs with CLONE_NEWUSER if !CONFIG_USER_NS

Note that EINVAL can occur with CLONE_NEWUSER if the kernel was
not configured with CONFIG_USER_NS.

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

clone.2: tfix

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

unix.7: wfix: s/foreign process/peer process/

The more common parlance these days is, I think, "peer".

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

socket.7, unix.7: Move text describing SO_PEERCRED from socket(7) to unix(7)

This is, AFAIK, an option specific to UNIX domain sockets, so
place it in unix(7).

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

unix.7: Refer reader to socket(7) for information about SO_PEEK_OFF

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

socket.7: Refer reader to unix(7) for information on SO_PASSSEC

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

tcp.7, udp.7: Add a reference to socket(7) noting existence of further socket options

Some other socket options that are applicable for TCP and UDP sockets
are documented in socket(7), so help the reader by pointing them at
that page.

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

udp.7: srcfix: add FIXME

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

unix.7: tfix

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

unix.7: Document SCM_SECURITY ancillary data

And fix a wording error in the description of SO_PASSSEC.

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

unix.7: Document SO_PASSSEC

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

cmsg.3: ffix

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

select_tut.2: Diagnose inet_aton() errors with simple fprintf() (not perror())

When it fails, inet_aton() does not set errno, so using
perror() is not appropriate.

Reported-by: Antonio Chirizzi <antonio.chirizzi@gmail.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

proc.5: Explain how to determine top-most mount in /proc/PID/mountinfo

Explain how to determine the top-most mount at a particular
location by inspecting /proc/PID/mountinfo.

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

chroot.2: Mention /proc/[pid]/root

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

statx.2: Library support for statx() was added in glibc 2.28

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

rename.2: glibc 2.28 adds library support for renameat2()

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

cmsg.3: Remove unnecessary 'fdptr' intermediate variable in example code

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

unix.7: Ancillary data forms a barrier when receiving on a stream socket

Thanks to a tip from Keith Packard:
https://keithp.com/blogs/fd-passing/
(Also verified by experiment.)

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

unix.7: One must send at least one byte of real data with ancillary data

When sending ancillary data, at least one byte of real data should
also be sent.  This is strictly necessary for stream sockets
(verified by experiment). It is not required for datagram sockets
on Linux (verified by experiment), but portable applications
should do so.

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

unix.7: Clarify treatment of incoming ancillary data if 'msg_control' is NULL

If no buffer is supplied for incoming ancillary data, then
the data is lost.

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

unix.7: If the buffer to receive SCM_RIGHTS FDs is too small, FDs are closed

If the ancillary data buffer for receiving SCM_RIGHTS file
descriptors is too small, then the excess file descriptors are
automatically closed in the receiving process. Verified by
experiment.

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

unix.7: tfix

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

unix.7: ffix

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

send.2: tfix

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

recv.2: tfix

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

mount.2: Mention /proc/PID/mountinfo

Many people are unaware of the /proc/PID/mountinfo file. Provide
a helpful clue here.

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

mount_namespaces.7: SEE ALSO: add findmnt(8)

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

dlinfo.3: tfix

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

seccomp.2: wfix (to make it clearer at that seccomp affects threads)

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>