From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael Kerrisk (man-pages)" Subject: Re: [PATCH 1/1 v2] fanotify.7: BUGS, error handling in fanotify_read Date: Thu, 15 May 2014 05:32:11 +0200 Message-ID: <5374353B.7000601@gmail.com> References: <5373ADF9.4020505@bfs.de> <1400091016-17670-1-git-send-email-xypron.glpk@gmx.de> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1400091016-17670-1-git-send-email-xypron.glpk-Mmb7MZpHnFY@public.gmane.org> Sender: linux-man-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Heinrich Schuchardt Cc: mtk.manpages-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, linux-man-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Jan Kara , Eric Paris List-Id: linux-man@vger.kernel.org On 05/14/2014 08:10 PM, Heinrich Schuchardt wrote: > The patch in > http://www.spinics.net/lists/linux-man/msg05589.html > was not accepted. > > Michael Kerrisk suggested in a private mail to add a comment > in the BUGS section. Hi Heinrich, Thanks! I've applied this patch (and fixed a few typos) and added Reviewed-by: Jan Kara Cheers, Michael > Signed-off-by: Heinrich Schuchardt > --- > man7/fanotify.7 | 14 ++++++++++++-- > 1 file changed, 12 insertions(+), 2 deletions(-) > > diff --git a/man7/fanotify.7 b/man7/fanotify.7 > index 2a92908..c6cec7c 100644 > --- a/man7/fanotify.7 > +++ b/man7/fanotify.7 > @@ -164,7 +164,7 @@ so that multiple events can be retrieved by a single > The return value of > .BR read (2) > is the number of bytes placed in the buffer, > -or \-1 in case of an error. > +or \-1 in case of an error (but see BUGS). > > The fields of the > .I fanotify_event_metadata > @@ -468,7 +468,7 @@ The event queue can overflow. > In this case, events are lost. > .SH BUGS > As of Linux 3.15, > -the following bug exists: > +the following bugs exists: > .IP * 3 > .\" FIXME: A patch was proposed. > When an event is generated, > @@ -478,6 +478,16 @@ before passing a file descriptor for that file. > This poses a security risk, when the > .B CAP_SYS_ADMIN > capability is set for programs executed by unprivileged users. > +.IP * > +If a call to > +.BR read( 2 ) > +processes multiple events from the fanotify queue and an error occurs, the > +return value will be the cumulated length of the events successfully copied to > +the user space buffer before the error occured. > +The return value will not be \-1. > +.I errno > +will not be set. > +Thus, the user program has no way to detect the error. > .SH EXAMPLE > The following program demonstrates the usage of the fanotify API. > It marks the mount point passed as a command-line argument > -- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ Linux/UNIX System Programming Training: http://man7.org/training/ -- To unsubscribe from this list: send the line "unsubscribe linux-man" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html