When calling msgrcv() with the MSG_COPY flag, it will report
EINVAL error even we if have disabled CONFIG_CHECKPOINT_RESTORE.
ENOSYS will be reported only if we also specify the IPC_NOWAIT
flag.
[mtk: edited commit message]
Notes from mtk:
The relevant kernel code is this:
[[
#ifdef CONFIG_CHECKPOINT_RESTORE
...
#else
static inline struct msg_msg *prepare_copy(void __user *buf, size_t bufsz)
{
return ERR_PTR(-ENOSYS);
}
...
static long do_msgrcv(int msqid, void __user *buf, size_t bufsz, long
msgtyp, int msgflg,
long (*msg_handler)(void __user *, struct msg_msg *, size_t))
{
...
if (msgflg & MSG_COPY) {
if ((msgflg & MSG_EXCEPT) || !(msgflg & IPC_NOWAIT))
return -EINVAL;
copy = prepare_copy(buf, min_t(size_t, bufsz, ns->msg_ctlmax));
...
}
]]
We'll only hit the ENOSYS error if:
(1) MSG_COPY was specified;
(2) IPC_NOWAIT was not specified; and
(3) CONFIG_CHECKPOINT_RESTORE was not enabled.
Signed-off-by: Yang Xu <xuyang2018.jy@cn.fujitsu.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
The type `struct msgbuf *` is implicitly casted to `const void *`.
Not only that, but the explicit cast to `void *` was slightly
misleading.
Explicitly casting can silence warnings when mistakes are made, so it's
better to remove those casts when possible.
Signed-off-by: Alejandro Colomar <colomar.6.4.3@gmail.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Rather than:
sometype x;
for (x = ....; ...)
use
for (sometype x = ...; ...)
This brings the declaration and use closer together (thus aiding
readability) and also clearly indicates the scope of the loop
counter variable.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Use ``sizeof`` consistently through all the examples in the following
way:
- Use the name of the variable instead of its type as argument for
``sizeof``.
Rationale:
https://www.kernel.org/doc/html/v5.8/process/coding-style.html#allocating-memory
Signed-off-by: Alejandro Colomar <colomar.6.4.3@gmail.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Use ``sizeof`` consistently through all the examples in the following
way:
- Use the name of the variable instead of its type as argument for
``sizeof``.
Rationale:
https://www.kernel.org/doc/html/v5.8/process/coding-style.html#allocating-memory
Signed-off-by: Alejandro Colomar <colomar.6.4.3@gmail.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Use ``sizeof`` consistently through all the examples in the following
way:
- Use the name of the variable instead of its type as argument for
``sizeof``.
Rationale:
https://www.kernel.org/doc/html/v5.8/process/coding-style.html#allocating-memory
Signed-off-by: Alejandro Colomar <colomar.6.4.3@gmail.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Use ``sizeof`` consistently through all the examples in the following
way:
- Use the name of the variable instead of its type as argument for
``sizeof``.
Rationale:
https://www.kernel.org/doc/html/v5.8/process/coding-style.html#allocating-memory
Signed-off-by: Alejandro Colomar <colomar.6.4.3@gmail.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Use ``sizeof`` consistently through all the examples in the following
way:
- Use the name of the variable instead of its type as argument for
``sizeof``.
Rationale:
https://www.kernel.org/doc/html/v5.8/process/coding-style.html#allocating-memory
Signed-off-by: Alejandro Colomar <colomar.6.4.3@gmail.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Use ``sizeof`` consistently through all the examples in the following
way:
- Use the name of the variable instead of its type as argument for
``sizeof``.
Rationale:
https://www.kernel.org/doc/html/v5.8/process/coding-style.html#allocating-memory
Signed-off-by: Alejandro Colomar <colomar.6.4.3@gmail.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Use ``sizeof`` consistently through all the examples in the following
way:
- Use the name of the variable instead of its type as argument for
``sizeof``.
Rationale:
https://www.kernel.org/doc/html/v5.8/process/coding-style.html#allocating-memory
Signed-off-by: Alejandro Colomar <colomar.6.4.3@gmail.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Document fanotify_init(2) flag FAN_REPORT_NAME and the format of
the event info type FAN_EVENT_INFO_TYPE_DFID_NAME.
The fanotify_fid.c example is extended to also report the name of
the created file or subdirectory.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Matthew Bobrowski <mbobrowski@mbobrowski.org>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Document fanotify_init(2) flag FAN_REPORT_DIR_FID and event info
type FAN_EVENT_INFO_TYPE_DFID.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Matthew Bobrowski <mbobrowski@mbobrowski.org>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
With fanotify_init(2) flag FAN_REPORT_FID, the group identifies
filesystem objects by file handles in a single event info record
of type FAN_EVENT_INFO_TYPE_FID.
We intend to add support for new fanotify_init(2) flags for which
the group identifies filesystem objects by file handles and add
more event info record types.
To that end, start by changing the language of the man page to
refer to a "group that identifies filesystem objects by file
handles" instead of referring to the FAN_REPORT_FID flag and
document the extended event format structure in a more generic
manner that allows more than a single event info record and not
only a record of type FAN_EVENT_INFO_TYPE_FID.
Clarify that the object identified by the file handle refers to
the directory in directory entry modification events.
Remove a note about directory entry modification events and
monitoring a mount point that I found to be too confusing and out
of context.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Matthew Bobrowski <mbobrowski@mbobrowski.org>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Use 'struct timespec', not 'struct timeval', and adjust
the variable name accordingly.
Reported-by: Tony May <tony.may@mediakind.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Killing a thread with SECCOMP_RET_KILL_THREAD is very likely
to leave the rest of the process in a broken state.
Wording pretty much taken from Rick Felker's suggestion.
Reported-by: Rich Felker <dalias@libc.org>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
A naked tilde ("~") renders poorly in PDF. Instead use "\(ti",
which renders better in a PDF, and produces the same glyph
when rendering on a terminal.
Reported-by: Geoff Clare <gwc@opengroup.org>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Historically, a comment of the following form at the top of a
manual page was used to indicate too man(1) that the use of tbl(1)
was required in order to process tables:
'\" t
However, at least as far back as 2001 (according to Branden),
man-db's man(1) automatically uses tbl(1) as needed, rendering
this comment unnecessary. And indeed many existing pages in
man-pages that have tables don't have this comment at the top of
the file. So, drop the comment from those files where it is
present.
[mtk: completely rewrote commit message]
Reported-by: G. Branden Robinson <g.branden.robinson@gmail.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Add some paragraph breaks to the discussion of 'mode' to make
the details a bit easier to read.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
The \" comment produces blank lines. Use the .\" that the vast
majority of the codebase uses instead.
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Close the PID file descriptor in the example program, to hint to
the reader that like every other kind of file descriptor, a PID FD
should be closed.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Michael Kerrisk