From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Kara Subject: Re: [PATCH 1/1 v2] fanotify.7: BUGS, error handling in fanotify_read Date: Wed, 14 May 2014 22:54:04 +0200 Message-ID: <20140514205404.GA18511@quack.suse.cz> References: <5373ADF9.4020505@bfs.de> <1400091016-17670-1-git-send-email-xypron.glpk@gmx.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-man-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: "Michael Kerrisk (man-pages)" Cc: Heinrich Schuchardt , linux-man , Jan Kara , Eric Paris List-Id: linux-man@vger.kernel.org Hello, On Wed 14-05-14 20:52:12, Michael Kerrisk (man-pages) wrote: > Do you have any comments/additions for this man-pages patch? No, it looks good to me. Honza > On Wed, May 14, 2014 at 8:10 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. > > > > 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 > > -- > > 2.0.0.rc0 > > > > > > -- > Michael Kerrisk > Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ > Linux/UNIX System Programming Training: http://man7.org/training/ -- Jan Kara SUSE Labs, CR -- 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