zed.8: modernise

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz>
Closes #12125

man/man8/zed.8.in

@@ -10,240 +10,247 @@
 .\" "OPENSOLARIS.LICENSE" or at <http://opensource.org/licenses/CDDL-1.0>.
 .\" You may not use this file except in compliance with the license.
 .\"
-.TH ZED 8 "Aug 24, 2020" OpenZFS
+.\" Developed at Lawrence Livermore National Laboratory (LLNL-CODE-403049)
-
+.\"
-.SH NAME
+.Dd May 26, 2021
-ZED \- ZFS Event Daemon
+.Dt ZED 8
-
+.Os
-.SH SYNOPSIS
+.
-.HP
+.Sh NAME
-.B zed
+.Nm ZED
-.\" [\fB\-c\fR \fIconfigfile\fR]
+.Nd ZFS Event Daemon
-[\fB\-d\fR \fIzedletdir\fR]
+.Sh SYNOPSIS
-[\fB\-f\fR]
+.Nm
-[\fB\-F\fR]
+.Op Fl fFhILMvVZ
-[\fB\-h\fR]
+.Op Fl d Ar zedletdir
-[\fB\-I\fR]
+.Op Fl p Ar pidfile
-[\fB\-L\fR]
+.Op Fl P Ar path
-[\fB\-M\fR]
+.Op Fl s Ar statefile
-[\fB\-p\fR \fIpidfile\fR]
+.Op Fl j Ar jobs
-[\fB\-P\fR \fIpath\fR]
+.
-[\fB\-s\fR \fIstatefile\fR]
+.Sh DESCRIPTION
-[\fB\-j\fR \fIjobs\fR]
+The
-[\fB\-v\fR]
+.Nm
-[\fB\-V\fR]
+(ZFS Event Daemon) monitors events generated by the ZFS kernel
-[\fB\-Z\fR]
+module.
-
+When a zevent (ZFS Event) is posted, the
-.SH DESCRIPTION
+.Nm
-.PP
+will run any ZEDLETs (ZFS Event Daemon Linkage for Executable Tasks)
-\fBZED\fR (ZFS Event Daemon) monitors events generated by the ZFS kernel
+that have been enabled for the corresponding zevent class.
-module.  When a zevent (ZFS Event) is posted, \fBZED\fR will run any ZEDLETs
+.
-(ZFS Event Daemon Linkage for Executable Tasks) that have been enabled for the
+.Sh OPTIONS
-corresponding zevent class.
+.Bl -tag -width "-h"
-
+.It Fl h
-.SH OPTIONS
-.TP
-.BI \-h
 Display a summary of the command-line options.
-.TP
+.It Fl L
-.BI \-L
 Display license information.
-.TP
+.It Fl V
-.BI \-V
 Display version information.
-.TP
+.It Fl v
-.BI \-v
 Be verbose.
-.TP
+.It Fl f
-.BI \-f
 Force the daemon to run if at all possible, disabling security checks and
-throwing caution to the wind.  Not recommended for use in production.
+throwing caution to the wind.
-.TP
+Not recommended for use in production.
-.BI \-F
+.It Fl F
-Run the daemon in the foreground.
+Don't daemonise: remain attached to the controlling terminal,
-.TP
+log to the standard I/O streams.
-.BI \-M
+.It Fl M
 Lock all current and future pages in the virtual memory address space.
 This may help the daemon remain responsive when the system is under heavy
 memory pressure.
-.TP
+.It Fl I
-.BI \-I
+Request that the daemon idle rather than exit when the kernel modules are not loaded.
-Request that the daemon idle rather than exit when the kernel modules are
+Processing of events will start, or resume, when the kernel modules are (re)loaded.
-not loaded. Processing of events will start, or resume, when the kernel
+Under Linux the kernel modules cannot be unloaded while the daemon is running.
-modules are (re)loaded. Under Linux the kernel modules cannot be unloaded
+.It Fl Z
-while the daemon is running.
-.TP
-.BI \-Z
 Zero the daemon's state, thereby allowing zevents still within the kernel
 to be reprocessed.
-.TP
+.It Fl d Ar zedletdir
-.BI \-d\  zedletdir
 Read the enabled ZEDLETs from the specified directory.
-.TP
+.It Fl p Ar pidfile
-.BI \-p\  pidfile
 Write the daemon's process ID to the specified file.
-.TP
+.It Fl P Ar path
-.BI \-P\  path
+Custom
-Custom $PATH for zedlets to use.  Normally zedlets run in a locked-down
+.Ev $PATH
-environment, with hardcoded paths to the ZFS commands ($ZFS, $ZPOOL, $ZED, ...),
+for zedlets to use.
-and a hardcoded $PATH.  This is done for security reasons.  However, the
+Normally zedlets run in a locked-down environment, with hardcoded paths to the ZFS commands
-ZFS test suite uses a custom PATH for its ZFS commands, and passes it to zed
+.Pq Ev $ZFS , $ZPOOL , $ZED , ... ,
-with -P.  In short, -P is only to be used by the ZFS test suite; never use
+and a hard-coded
+.Ev $PATH .
+This is done for security reasons.
+However, the ZFS test suite uses a custom PATH for its ZFS commands, and passes it to
+.Nm
+with
+.Fl P .
+In short,
+.Fl P
+is only to be used by the ZFS test suite; never use
 it in production!
-.TP
+.It Fl s Ar statefile
-.BI \-s\  statefile
 Write the daemon's state to the specified file.
-.TP
+.It Fl j Ar jobs
-.BI \-j\  jobs
+Allow at most
-Allow at most \fIjobs\fR ZEDLETs to run concurrently,
+.Ar jobs
+ZEDLETs to run concurrently,
 delaying execution of new ones until they finish.
-Defaults to 16.
+Defaults to
-.SH ZEVENTS
+.Sy 16 .
-.PP
+.El
-A zevent is comprised of a list of nvpairs (name/value pairs).  Each zevent
+.Sh ZEVENTS
-contains an EID (Event IDentifier) that uniquely identifies it throughout
+A zevent is comprised of a list of nvpairs (name/value pairs).
+Each zevent contains an EID (Event IDentifier) that uniquely identifies it throughout
 the lifetime of the loaded ZFS kernel module; this EID is a monotonically
 increasing integer that resets to 1 each time the kernel module is loaded.
 Each zevent also contains a class string that identifies the type of event.
 For brevity, a subclass string is defined that omits the leading components
-of the class string.  Additional nvpairs exist to provide event details.
+of the class string.
-.PP
+Additional nvpairs exist to provide event details.
+.Pp
 The kernel maintains a list of recent zevents that can be viewed (along with
-their associated lists of nvpairs) using the "\fBzpool events \-v\fR" command.
+their associated lists of nvpairs) using the
-
+.Nm zpool Cm events Fl v
-.SH CONFIGURATION
+command.
-.PP
+.
+.Sh CONFIGURATION
 ZEDLETs to be invoked in response to zevents are located in the
-\fIenabled-zedlets\fR directory.  These can be symlinked or copied from the
+.Em enabled-zedlets
-\fIinstalled-zedlets\fR directory; symlinks allow for automatic updates
+directory
+.Pq Ar zedletdir .
+These can be symlinked or copied from the
+.Em installed-zedlets
+directory; symlinks allow for automatic updates
 from the installed ZEDLETs, whereas copies preserve local modifications.
 As a security measure, since ownership change is a privileged operation,
-ZEDLETs must be owned by root.  They must have execute permissions for the user,
+ZEDLETs must be owned by root.
+They must have execute permissions for the user,
 but they must not have write permissions for group or other.
 Dotfiles are ignored.
-.PP
+.Pp
 ZEDLETs are named after the zevent class for which they should be invoked.
 In particular, a ZEDLET will be invoked for a given zevent if either its
 class or subclass string is a prefix of its filename (and is followed by
-a non-alphabetic character).  As a special case, the prefix "all" matches
+a non-alphabetic character).
-all zevents.  Multiple ZEDLETs may be invoked for a given zevent.
+As a special case, the prefix
-
+.Sy all
-.SH ZEDLETS
+matches all zevents.
-.PP
+Multiple ZEDLETs may be invoked for a given zevent.
+.
+.Sh ZEDLETS
 ZEDLETs are executables invoked by the ZED in response to a given zevent.
 They should be written under the presumption they can be invoked concurrently,
 and they should use appropriate locking to access any shared resources.
 Common variables used by ZEDLETs can be stored in the default rc file which
-is sourced by scripts; these variables should be prefixed with "ZED_".
+is sourced by scripts; these variables should be prefixed with
-.PP
+.Sy ZED_ .
+.Pp
 The zevent nvpairs are passed to ZEDLETs as environment variables.
 Each nvpair name is converted to an environment variable in the following
-manner: 1) it is prefixed with "ZEVENT_", 2) it is converted to uppercase,
+manner:
-and 3) each non-alphanumeric character is converted to an underscore.
+.Bl -enum
+.It
+it is prefixed with
+.Sy ZEVENT_ ,
+.It
+it is converted to uppercase, and
+.It
+each non-alphanumeric character is converted to an underscore.
+.El
+.Pp
 Some additional environment variables have been defined to present certain
-nvpair values in a more convenient form.  An incomplete list of zevent
+nvpair values in a more convenient form.
-environment variables is as follows:
+An incomplete list of zevent environment variables is as follows:
-.TP
+.Bl -tag -width "ZEVENT_TIME_STRING"
-.B
+.It Sy ZEVENT_EID
-ZEVENT_EID
 The Event IDentifier.
-.TP
+.It Sy ZEVENT_CLASS
-.B
-ZEVENT_CLASS
 The zevent class string.
-.TP
+.It Sy ZEVENT_SUBCLASS
-.B
-ZEVENT_SUBCLASS
 The zevent subclass string.
-.TP
+.It Sy ZEVENT_TIME
-.B
-ZEVENT_TIME
 The time at which the zevent was posted as
-"\fIseconds\fR\ \fInanoseconds\fR" since the Epoch.
+.Dq Em seconds nanoseconds
-.TP
+since the Epoch.
-.B
+.It Sy ZEVENT_TIME_SECS
-ZEVENT_TIME_SECS
+The
-The \fIseconds\fR component of ZEVENT_TIME.
+.Em seconds
-.TP
+component of
-.B
+.Sy ZEVENT_TIME .
-ZEVENT_TIME_NSECS
+.It Sy ZEVENT_TIME_NSECS
-The \fInanoseconds\fR component of ZEVENT_TIME.
+The
-.TP
+.Em nanoseconds
-.B
+component of
-ZEVENT_TIME_STRING
+.Sy ZEVENT_TIME .
-An almost-RFC3339-compliant string for ZEVENT_TIME.
+.It Sy ZEVENT_TIME_STRING
-.PP
+An almost-RFC3339-compliant string for
+.Sy ZEVENT_TIME .
+.El
+.Pp
 Additionally, the following ZED & ZFS variables are defined:
-.TP
+.Bl -tag -width "ZEVENT_TIME_STRING"
-.B
+.It Sy ZED_PID
-ZED_PID
 The daemon's process ID.
-.TP
+.It Sy ZED_ZEDLET_DIR
-.B
+The daemon's current
-ZED_ZEDLET_DIR
+.Em enabled-zedlets
-The daemon's current \fIenabled-zedlets\fR directory.
+directory.
-.TP
+.It Sy ZFS_ALIAS
-.B
+The alias
-ZFS_ALIAS
+.Pq Dq Em name Ns - Ns Em version Ns - Ns Em release
-The ZFS alias (\fIname-version-release\fR) string used to build the daemon.
+string of the ZFS distribution the daemon is part of.
-.TP
+.It Sy ZFS_VERSION
-.B
+The ZFS version the daemon is part of.
-ZFS_VERSION
+.It Sy ZFS_RELEASE
-The ZFS version used to build the daemon.
+The ZFS release the daemon is part of.
-.TP
+.El
-.B
+.Pp
-ZFS_RELEASE
+ZEDLETs may need to call other ZFS commands.
-The ZFS release used to build the daemon.
+The installation paths of the following executables are defined as environment variables:
-.PP
+.Sy ZDB ,
-ZEDLETs may need to call other ZFS commands.  The installation paths of
+.Sy ZED ,
-the following executables are defined: \fBZDB\fR, \fBZED\fR, \fBZFS\fR,
+.Sy ZFS ,
-\fBZINJECT\fR, and \fBZPOOL\fR.  These variables can be overridden in the
+.Sy ZINJECT ,
-rc file if needed.
+and
-
+.Sy ZPOOL .
-.SH FILES
+These variables may be overridden in the rc file.
-.TP
+.
-.I @sysconfdir@/zfs/zed.d
+.Sh FILES
+.Bl -tag -width "-c"
+.It Pa @sysconfdir@/zfs/zed.d
 The default directory for enabled ZEDLETs.
-.TP
+.It Pa @sysconfdir@/zfs/zed.d/zed.rc
-.I @sysconfdir@/zfs/zed.d/zed.rc
 The default rc file for common variables used by ZEDLETs.
-.TP
+.It Pa @zfsexecdir@/zed.d
-.I @zfsexecdir@/zed.d
 The default directory for installed ZEDLETs.
-.TP
+.It Pa @runstatedir@/zed.pid
-.I @runstatedir@/zed.pid
 The default file containing the daemon's process ID.
-.TP
+.It Pa @runstatedir@/zed.state
-.I @runstatedir@/zed.state
 The default file containing the daemon's state.
-
+.El
-.SH SIGNALS
+.
-.TP
+.Sh SIGNALS
-.B HUP
+.Bl -tag -width "-c"
+.It Sy SIGHUP
 Reconfigure the daemon and rescan the directory for enabled ZEDLETs.
-.TP
+.It Sy SIGTERM , SIGINT
-.B TERM
 Terminate the daemon.
-
+.El
-.SH NOTES
+.
-.PP
+.Sh SEE ALSO
-\fBZED\fR requires root privileges.
+.Xr zfs-events 5 ,
-.\" Do not taunt zed.
+.Xr zfs 8 ,
-
+.Xr zpool 8 ,
-.SH BUGS
+.Xr zpool-events 8
-.PP
+.
+.Sh NOTES
+The
+.Nm
+requires root privileges.
+.Pp
+Do not taunt the
+.Nm .
+.
+.Sh BUGS
 ZEDLETs are unable to return state/status information to the kernel.
-.PP
+.Pp
 Internationalization support via gettext has not been added.
-
-.SH LICENSE
-.PP
-\fBZED\fR (ZFS Event Daemon) is distributed under the terms of the
-Common Development and Distribution License Version 1.0 (CDDL\-1.0).
-.PP
-Developed at Lawrence Livermore National Laboratory (LLNL\-CODE\-403049).
-
-.SH SEE ALSO
-.BR zfs (8),
-.BR zpool (8)
-.BR zpool-events (8)