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Add vlogger(8)
vlogger(8) is a alternative to logger(1), by default it sends messages from stdin to syslog. The main reason to replace logger(1) is, that logger only connects once to the syslog socket in default mode and puts all messages into the void if syslog is not running at the time. logger(1) has a new `--socket-errors=on` mode which would work, but some void uses don't use syslog at all and in this case the log service would constantly restart. As a bonus vlogger(8) looks for /etc/vlogger and if its executable it just executes it and is replaced by it. This can be used to avoid syslog and just write all logs to files with svlogd(8) as example, without having to edit all log services.
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‎.gitignore‎

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halt
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pause
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vlogger

‎Makefile‎

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@@ -4,6 +4,7 @@ SCRIPTS= 1 2 3 ctrlaltdel
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all:
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$(CC) $(CFLAGS) halt.c -o halt $(LDFLAGS)
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$(CC) $(CFLAGS) pause.c -o pause $(LDFLAGS)
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$(CC) $(CFLAGS) vlogger.c -o vlogger $(LDFLAGS)
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install:
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install -d ${DESTDIR}/${PREFIX}/sbin
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install -m644 shutdown.8 ${DESTDIR}/${PREFIX}/share/man/man8
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install -m644 halt.8 ${DESTDIR}/${PREFIX}/share/man/man8
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install -m644 modules-load.8 ${DESTDIR}/${PREFIX}/share/man/man8
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install -m644 vlogger.8 ${DESTDIR}/${PREFIX}/share/man/man8
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ln -sf halt.8 ${DESTDIR}/${PREFIX}/share/man/man8/poweroff.8
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ln -sf halt.8 ${DESTDIR}/${PREFIX}/share/man/man8/reboot.8
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install -d ${DESTDIR}/etc/sv

‎vlogger.8‎

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.Dd March 1, 2017
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.Dt VLOGGER 8
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.Os Linux
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.Sh NAME
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.Nm vlogger
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.Nd log messages to syslog or an arbitrary executable
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.Sh SYNOPSIS
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.Nm vlogger
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.Op Fl p Ar priority
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.Op Fl t Ar tag
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.Sh DESCRIPTION
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By default,
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.Nm
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reads lines from
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.Dv stdin
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and sends them to syslog.
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If the file
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.Pa /etc/vlogger
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exists and is executable it is executed with
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.Ar tag
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as only argument and replaces
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.Nm .
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.Pp
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If
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.Nm
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is executed as a log service for runit or another daemontools like
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supervision suite it uses the service name as default
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.Ar tag .
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As example if
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.Nm
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is linked to
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.Dv /var/service/foo/log/run
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it uses
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.Dv foo
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as default
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.Ar tag .
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.Bl -tag -width indent
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.It Fl p Ar priority
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The.
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.Ar priority
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can be
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.Pa facility.level
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or just
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.Pa facility .
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See
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.Sx FACILITIES ,
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.Sx LEVELS
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or
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.Xr syslog 3 .
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The default is
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.Pa daemon.info .
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.It Fl t Ar tag
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Defines the
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.Xr openlog 3
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.Pa ident
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which is used as prefix for each log message or passed as first argument to
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.Pa /etc/vlogger .
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.El
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.Sh FACILITIES
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.Bl -tag -width 11n -compact
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.It auth
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.It authpriv
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.It cron
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.It daemon
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.It ftp
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.It kern
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can not be used from userspace replaced with
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.Pa daemon .
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.It lpr
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.It mail
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.It news
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.It syslog
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.It user
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.It uucp
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.It local[0-7]
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.It security
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deprecated synonym for
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.Pa auth.
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.El
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.Sh LEVELS
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.Bl -tag -width 11n -compact
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.It emerg
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.It alert
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.It crit
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.It err
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.It warning
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.It notice
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.It info
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.It debug
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.It panic
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deprecated synonym for
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.Pa emerg .
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.It error
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deprecated synonym for
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.Ar err .
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.It warn
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deprecated synonym for
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.Pa warning .
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.El
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.Sh FILES
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.Bl -tag -width indent
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.It /etc/vlogger
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An optional executable file that is used to to handle the messages.
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It is executed with
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.Ar tag
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as first argument and replaces the
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.Nm
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process.
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.El
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.Sh EXIT STATUS
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.Ex -std
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.Sh EXAMPLES
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.Pa /etc/vlogger :
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.Bd -literal -offset indent
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#!/bin/sh
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exec svlogd /var/log/$1
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.Ed
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.Sh SEE ALSO
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.Xr logger 1 ,
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.Xr syslog 3 ,
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.Xr svlogd 8
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.Sh HISTORY
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This program is a replacement for the
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.Nm logger
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utility provided by
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.Nm util-linux .
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.Sh AUTHOR
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.An Duncan Overbruck Aq Mt mail@duncano.de
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.Sh LICENSE
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.Nm
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is in the public domain.
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.Pp
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To the extent possible under law,
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the creator of this work
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has waived all copyright and related or
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neighboring rights to this work.
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.Pp
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.Lk http://creativecommons.org/publicdomain/zero/1.0/

‎vlogger.c‎

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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <syslog.h>
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#include <unistd.h>
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typedef struct _code {
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const char *const c_name;
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int c_val;
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} CODE;
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CODE prioritynames[] = {
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{ "alert", LOG_ALERT },
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{ "crit", LOG_CRIT },
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{ "debug", LOG_DEBUG },
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{ "emerg", LOG_EMERG },
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{ "err", LOG_ERR },
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{ "error", LOG_ERR },
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{ "info", LOG_INFO },
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{ "notice", LOG_NOTICE },
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{ "panic", LOG_EMERG },
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{ "warn", LOG_WARNING },
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{ "warning", LOG_WARNING },
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{ 0, -1 }
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};
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CODE facilitynames[] = {
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{ "auth", LOG_AUTH },
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{ "authpriv", LOG_AUTHPRIV },
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{ "cron", LOG_CRON },
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{ "daemon", LOG_DAEMON },
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{ "ftp", LOG_FTP },
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{ "kern", LOG_KERN },
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{ "lpr", LOG_LPR },
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{ "mail", LOG_MAIL },
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{ "news", LOG_NEWS },
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{ "security", LOG_AUTH },
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{ "syslog", LOG_SYSLOG },
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{ "user", LOG_USER },
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{ "uucp", LOG_UUCP },
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{ "local0", LOG_LOCAL0 },
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{ "local1", LOG_LOCAL1 },
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{ "local2", LOG_LOCAL2 },
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{ "local3", LOG_LOCAL3 },
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{ "local4", LOG_LOCAL4 },
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{ "local5", LOG_LOCAL5 },
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{ "local6", LOG_LOCAL6 },
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{ "local7", LOG_LOCAL7 },
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{ 0, -1 }
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};
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static char *tag;
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static void
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strpriority(char *s, int *facility, int *level)
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{
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char *p;
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CODE *cp;
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if ((p = strchr(s, '.'))) {
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*p++ = 0;
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for (cp = prioritynames; cp->c_name; cp++) {
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if (strcmp(cp->c_name, p) == 0)
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*level = cp->c_val;
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}
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}
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if (*s)
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for (cp = facilitynames; cp->c_name; cp++) {
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if (strcmp(cp->c_name, s) == 0)
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*facility = cp->c_val;
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}
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}
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int
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main(int argc, char *argv[])
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{
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char c, *p;
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int facility = LOG_DAEMON;
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int level = LOG_INFO;
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if (((p = strrchr(*argv, '/')) && !strncmp(p+1, "run", 3)) &&
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(*p = 0, (p = strrchr(*argv, '/')) && !strncmp(p+1, "log", 3)) &&
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(*p = 0, (p = strrchr(*argv, '/'))) != 0) {
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tag = strdup(p+1);
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}
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while ((c = getopt(argc, argv, "p:t:")) != -1)
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switch (c) {
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case 'p': strpriority(optarg, &facility, &level); break;
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case 't': tag = optarg; break;
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default:
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fprintf(stderr, "usage: vlogger [-p priority] [-t tag]\n");
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exit(1);
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}
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if (access("/etc/vlogger", X_OK) != -1)
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execl("/etc/vlogger", "/etc/vlogger", tag, (char *)0);
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openlog(tag, 0, facility);
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char *line;
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size_t linelen = 0;
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ssize_t rd;
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while ((rd = getline(&line, &linelen, stdin)) != -1) {
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if (line[rd-1] == '\n')
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line[rd-1] = 0;
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syslog(level|facility, "%s", line);
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}
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return 1;
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}

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