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Edit File: sh.rotate

##
##  rotate -- Logfile rotation
##  Copyright (c) 2001-2008 Ralf S. Engelschall <rse@engelschall.com>
##
##  This file is part of shtool and free software; you can redistribute
##  it and/or modify it under the terms of the GNU General Public
##  License as published by the Free Software Foundation; either version
##  2 of the License, or (at your option) any later version.
##
##  This file is distributed in the hope that it will be useful,
##  but WITHOUT ANY WARRANTY; without even the implied warranty of
##  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
##  General Public License for more details.
##
##  You should have received a copy of the GNU General Public License
##  along with this program; if not, write to the Free Software
##  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
##  USA, or contact Ralf S. Engelschall <rse@engelschall.com>.
##

. ./sh.common

#   make sure we have at least one file to rotate
if [ ".$opt_n" = .0 ]; then
    echo "$msgprefix:Error: invalid argument \`$opt_n' to option -n." 1>&2
    shtool_exit 1
fi

#   canonicalize -s option argument
if [ ".$opt_s" != . ]; then
    if [ ".`expr $opt_s : '[0-9]*$'`" != .0 ]; then
        :
    elif [ ".`expr $opt_s : '[0-9]*[Kk]$'`" != .0 ]; then
        opt_s=`expr $opt_s : '$[0-9]*$[Kk]$'`
        opt_s=`expr $opt_s \* 1024`
    elif [ ".`expr $opt_s : '[0-9]*[Mm]$'`" != .0 ]; then
        opt_s=`expr $opt_s : '$[0-9]*$[Mm]$'`
        opt_s=`expr $opt_s \* 1048576` # 1024*1024
    elif [ ".`expr $opt_s : '[0-9]*[Gg]$'`" != .0 ]; then
        opt_s=`expr $opt_s : '$[0-9]*$[Gg]$'`
        opt_s=`expr $opt_s \* 1073741824` # 1024*1024*1024
    else
        echo "$msgprefix:Error: invalid argument \`$opt_s' to option -s." 1>&2
        shtool_exit 1
    fi
fi

#   option -d/-z consistency
if [ ".$opt_d" = .yes ] && [ ".$opt_z" = . ]; then
    echo "$msgprefix:Error: option -d requires option -z." 1>&2
    shtool_exit 1
fi

#   make sure target directory exists
if [ ".$opt_a" != . ]; then
    if [ ! -d $opt_a ]; then
        if [ ".$opt_f" = .no ]; then
            echo "$msgprefix:Error: archive directory \`$opt_a' does not exist." 1>&2
            shtool_exit 1
        fi
        mkdir $opt_a || shtool_exit $?
        chmod 755 $opt_a
    fi
    if [ ! -w $opt_a ]; then
        echo "$msgprefix:Error: archive directory \`$opt_a' not writable." 1>&2
        shtool_exit 1
    fi
fi

#   determine compression approach
if [ ".$opt_z" != . ]; then
    comp_lvl="$opt_z"
    comp_prg=""
    case $comp_lvl in
        *:* ) eval `echo $comp_lvl |\
                    sed -e 's%^$.*$:$.*$$%comp_prg="\1"; comp_lvl="\2"%'` ;;
    esac

#   compression level consistency
    case $comp_lvl in
        [0-9] )
            ;;
        * ) echo "$msgprefix:Error: invalid compression level \`$comp_lvl'" 1>&2
            shtool_exit 1
            ;;
    esac

#   determine a suitable compression tool
    if [ ".$comp_prg" = . ]; then
        #   check whether the test command supports the -x option
        if [ -x /bin/sh ] 2>/dev/null; then
            minusx="-x"
        else
            minusx="-r"
        fi
        #   search for tools in $PATH
        paths="`echo $PATH |\
                sed -e 's%/*:%:%g' -e 's%/*$%%' \
                    -e 's/^:/.:/' -e 's/::/:.:/g' -e 's/:$/:./' \
                    -e 's/:/ /g'`"
        for prg in bzip2 gzip compress; do
            for path in $paths; do
                if [ $minusx "$path/$prg" ] && [ ! -d "$path/$prg" ]; then
                    comp_prg="$prg"
                    break
                fi
            done
            if [ ".$comp_prg" != . ]; then
                break
            fi
        done
        if [ ".$comp_prg" = . ]; then
            echo "$msgprefix:Error: no suitable compression tool found in \$PATH" 1>&2
            shtool_exit 1
        fi
    fi

#   determine standard compression extension
    #   and make sure it is a known tool
    case $comp_prg in
        */bzip2    | bzip2    ) comp_ext="bz2" comp_lvl="-$comp_lvl" ;;
        */gzip     | gzip     ) comp_ext="gz"  comp_lvl="-$comp_lvl" ;;
        */compress | compress ) comp_ext="Z";  comp_lvl=""           ;;
        * ) echo "$msgprefix:Error: tool \`$comp_prg' is not a known compression tool" 1>&2
            shtool_exit 1
            ;;
    esac
    comp_suf=".$comp_ext"
fi

#   iterate over all given logfile arguments
for file in $*; do
    #   make sure the logfile exists
    if [ ! -f $file ]; then
        if [ ".$opt_f" = .yes ]; then
            continue
        fi
        echo "$msgprefix:Error: logfile \`$file' not found" 1>&2
        shtool_exit 1
    fi

#   determine log directory (where original logfile is placed)
    ldir="."
    case $file in
        */* ) eval `echo $file | sed -e 's%^$.*$/$[^/]*$$%ldir="\1"; file="\2";%'` ;;
    esac

#   determine archive directory (where rotated logfiles are placed)
    adir="$ldir"
    if [ ".$opt_a" != . ]; then
        case "$opt_a" in
            /* | ./* ) adir="$opt_a" ;;
            * ) adir="$ldir/$opt_a"  ;;
        esac
    fi

#   optionally take logfile size into account
    if [ ".$opt_s" != . ]; then
        #   determine size of logfile
        set -- `env -i /bin/ls -l "$ldir/$file" | sed -e "s;$ldir/$file;;" |\
                sed -e 's; -> .*$;;' -e 's;[ 	][ 	]*; ;g'`
        n=`expr $# - 3`
        eval "size=\`echo \${$n}\`"

#   skip logfile if size is still too small
        if [ $size -lt $opt_s ]; then
            if [ ".$opt_v" = .yes ]; then
                echo "$ldir/$file: still too small in size -- skipping"
            fi
            continue
        fi
    fi

#   verbosity
    if [ ".$opt_v" = .yes ]; then
        echo "rotating $ldir/$file"
    fi

#   execute prolog
    if [ ".$opt_P" != . ]; then
        if [ ".$opt_t" = .yes ]; then
            echo "$opt_P"
        fi
        eval $opt_P
        [ $? -ne 0 ] && shtool_exit $?
    fi

#   kick away out-rotated logfile
    n=`expr $opt_n - 1`
    n=`echo dummy | awk "{ printf(\"%0${opt_p}d\", n); }" n=$n`
    if [ -f "${adir}/${file}.${n}${comp_suf}" ]; then
        #   optionally migrate away the out-rotated logfile
        if [ ".$opt_M" != . ]; then
            if [ ".$opt_t" = .yes ]; then
                echo "$opt_M ${adir}/${file}.${n}${comp_suf}"
            fi
            eval "$opt_M ${adir}/${file}.${n}${comp_suf}"
            [ $? -ne 0 ] && shtool_exit $?
        fi
        #   finally get rid of the out-rotated logfile
        if [ ".$opt_t" = .yes ]; then
            echo "rm -f ${adir}/${file}.${n}${comp_suf}"
        fi
        rm -f ${adir}/${file}.${n}${comp_suf} || shtool_exit $?
    fi

#   rotate already archived logfiles
    while [ $n -gt 0 ]; do
        m=$n
        n=`expr $n - 1`
        n=`echo dummy | awk "{ printf(\"%0${opt_p}d\", n); }" n=$n`
        if [ $n -eq 0 ] && [ ".$opt_d" = .yes ]; then
            #   special case: first rotation file under delayed compression situation
            if [ ! -f "${adir}/${file}.${n}" ]; then
                continue
            fi

#   compress file (delayed)
            if [ ".$opt_b" = .yes ]; then
                if [ ".$opt_t" = .yes ]; then
                    echo "mv ${adir}/${file}.${n} ${adir}/${file}.${m}"
                fi
                mv ${adir}/${file}.${n} ${adir}/${file}.${m} || shtool_exit $?
                if [ ".$opt_t" = .yes ]; then
                    echo "(${comp_prg} ${comp_lvl} <${adir}/${file}.${m} >${adir}/${file}.${m}${comp_suf}; rm -f ${adir}/${file}.${m}) &"
                fi
                ( ${comp_prg} ${comp_lvl} \
                      <${adir}/${file}.${m} \
                      >${adir}/${file}.${m}${comp_suf} || shtool_exit $?
                  rm -f ${adir}/${file}.${m} || shtool_exit $?
                ) </dev/null >/dev/null 2>&1 &
            else
                if [ ".$opt_t" = .yes ]; then
                    echo "${comp_prg} ${comp_lvl} <${adir}/${file}.${n} >${adir}/${file}.${m}${comp_suf}"
                fi
                ${comp_prg} ${comp_lvl} \
                    <${adir}/${file}.${n} \
                    >${adir}/${file}.${m}${comp_suf} || shtool_exit $?
                if [ ".$opt_t" = .yes ]; then
                    echo "rm -f ${adir}/${file}.${n}"
                fi
                rm -f ${adir}/${file}.${n} || shtool_exit $?
            fi

#   fix file attributes
            if [ ".$opt_o" != . ]; then
                if [ ".$opt_t" = .yes ]; then
                    echo "chown $opt_o ${adir}/${file}.${m}${comp_suf}"
                fi
                chown $opt_o ${adir}/${file}.${m}${comp_suf} || shtool_exit $?
            fi
            if [ ".$opt_g" != . ]; then
                if [ ".$opt_t" = .yes ]; then
                    echo "chgrp $opt_g ${adir}/${file}.${m}${comp_suf}"
                fi
                chgrp $opt_g ${adir}/${file}.${m}${comp_suf} || shtool_exit $?
            fi
            if [ ".$opt_m" != . ]; then
                if [ ".$opt_t" = .yes ]; then
                    echo "chmod $opt_m ${adir}/${file}.${m}${comp_suf}"
                fi
                chmod $opt_m ${adir}/${file}.${m}${comp_suf} || shtool_exit $?
            fi
        else
            #   standard case: second and following rotation file
            if [ ! -f "${adir}/${file}.${n}${comp_suf}" ]; then
                continue
            fi
            if [ ".$opt_t" = .yes ]; then
                echo "mv ${adir}/${file}.${n}${comp_suf} ${adir}/${file}.${m}${comp_suf}"
            fi
            mv ${adir}/${file}.${n}${comp_suf} ${adir}/${file}.${m}${comp_suf} || shtool_exit $?
        fi
    done

#   move away current logfile
    if [ ".$opt_c" = .yes ]; then
        #   approach: copy[+truncate]
        if [ ".$opt_t" = .yes ]; then
            echo "cp -p ${ldir}/${file} ${adir}/${file}.${n}"
        fi
        cp -p ${ldir}/${file} ${adir}/${file}.${n} || shtool_exit $?
        if [ ".$opt_r" = .no ]; then
            if [ ".$opt_t" = .yes ]; then
                echo "cp /dev/null ${ldir}/${file}"
            fi
            cp /dev/null ${ldir}/${file} || shtool_exit $?
        fi
    else
        #   approach: move[+touch]
        if [ ".$opt_t" = .yes ]; then
            echo "mv ${ldir}/${file} ${adir}/${file}.${n}"
        fi
        mv ${ldir}/${file} ${adir}/${file}.${n} || shtool_exit $?
        if [ ".$opt_r" = .no ]; then
            if [ ".$opt_t" = .yes ]; then
                echo "touch ${ldir}/${file}"
            fi
            touch ${ldir}/${file} || shtool_exit $?
            #   fix file attributes
            if [ ".$opt_o" != . ]; then
                if [ ".$opt_t" = .yes ]; then
                    echo "chown $opt_o ${ldir}/${file}"
                fi
                chown $opt_o ${ldir}/${file} || shtool_exit $?
            fi
            if [ ".$opt_g" != . ]; then
                if [ ".$opt_t" = .yes ]; then
                    echo "chgrp $opt_g ${ldir}/${file}"
                fi
                chgrp $opt_g ${ldir}/${file} || shtool_exit $?
            fi
            if [ ".$opt_m" != . ]; then
                if [ ".$opt_t" = .yes ]; then
                    echo "chmod $opt_m ${ldir}/${file}"
                fi
                chmod $opt_m ${ldir}/${file} || shtool_exit $?
            fi
        fi
    fi

#   regular compression step
    if [ ".$opt_z" != . ] && [ ".$opt_d" = .no ]; then
        #   compress file
        if [ ".$opt_b" = .yes ]; then
            if [ ".$opt_t" = .yes ]; then
                echo "(${comp_prg} ${comp_lvl} <${adir}/${file}.${n} >${adir}/${file}.${n}${comp_suf}; rm -f ${adir}/${file}.${n}) &"
            fi
            ( ${comp_prg} ${comp_lvl} \
                  <${adir}/${file}.${n} \
                  >${adir}/${file}.${n}${comp_suf} || shtool_exit $?
              rm -f ${adir}/${file}.${n} || shtool_exit $?
            ) </dev/null >/dev/null 2>&1 &
        else
            if [ ".$opt_t" = .yes ]; then
                echo "${comp_prg} ${comp_lvl} <${adir}/${file}.${n} >${adir}/${file}.${n}${comp_suf}"
            fi
            ${comp_prg} ${comp_lvl} \
                <${adir}/${file}.${n} \
                >${adir}/${file}.${n}${comp_suf} || shtool_exit $?
            if [ ".$opt_t" = .yes ]; then
                echo "rm -f ${opt_a}${file}.${n}"
            fi
            rm -f ${adir}/${file}.${n} || shtool_exit $?
        fi

#   fix file attributes
        if [ ".$opt_o" != . ]; then
            if [ ".$opt_t" = .yes ]; then
                echo "chown $opt_o ${adir}/${file}.${n}${comp_suf}"
            fi
            chown $opt_o ${adir}/${file}.${n}${comp_suf} || shtool_exit $?
        fi
        if [ ".$opt_g" != . ]; then
            if [ ".$opt_t" = .yes ]; then
                echo "chgrp $opt_g ${adir}/${file}.${n}${comp_suf}"
            fi
            chgrp $opt_g ${adir}/${file}.${n}${comp_suf} || shtool_exit $?
        fi
        if [ ".$opt_m" != . ]; then
            if [ ".$opt_t" = .yes ]; then
                echo "chmod $opt_m ${adir}/${file}.${n}${comp_suf}"
            fi
            chmod $opt_m ${adir}/${file}.${n}${comp_suf} || shtool_exit $?
        fi
    fi

#   execute epilog
    if [ ".$opt_E" != . ]; then
        if [ ".$opt_t" = .yes ]; then
            echo "$opt_E"
        fi
        eval $opt_E
        [ $? -ne 0 ] && shtool_exit $?
    fi
done

shtool_exit 0

##
##  manual page
##

=pod

=head1 NAME

B<shtool-rotate> - B<GNU shtool> log file rotation

=head1 SYNOPSIS

=head1 DESCRIPTION

This command rotates a logfile I<file> by subsequently creating up to
I<count> (optionally compressed) archive files of it. Archive files are
named "I<file>.I<number>[I<compress-suffix]>" where I<number> is the
version number, 0 being the newest and "I<count>-1" the oldest.

A rotation step consists of the following steps

1. remove last archive file
2. shift archive file numbers
3. create archive file 0 from I<file>
4. truncate/recreate I<file>

=head1 OPTIONS

The following command line options are available.

=over 4

=item B<-v>, B<--verbose>

Display some processing information.

=item B<-t>, B<--trace>

Enable the output of the essential shell commands which are executed.

=item B<-f>, B<--force>

Force silent creation of archive directory if it does not exists. Also
skip missing intermediate logfiles in the rotation step. Default is to
exit with error in both cases. FIXME

=item B<-n>, B<--num-files> I<count>

Create I<count> archive files. Default is 10.

=item B<-s>, B<--size> I<size>

Only rotate if logfile exceeds I<size>. The argument I<size> can be
specified also with the trailing units C<K> (kilo), C<M> (mega) or C<G>
(giga). The "prolog" and "epilog" are only executed if rotation actually
takes place.

=item B<-c>, B<--copy>

Copy I<file> to archive then truncate original. The default is to move
I<file> to archive.

Unless an application reopens its logfile it will continue to write
to the same file. In the default move case the application will write
to the archive which it had previously opened as I<file>. In the copy
case the application will write to the original I<file>. The drawback
of the copy approach is that logfile entries are lost when they are
written to I<file> between the execution of the copy and the truncation
operation. The drawback of the move approach is that the application
needs to detect the move or must be triggered to reopen its log (i.e.
through epilog).

=item B<-r>, B<--remove>

Removes I<file> after rotation instead of providing a new empty file.

=item B<-a>, B<--archive-dir> I<dir>

Specify the archive directory. Default is to create archives in the same
directory as I<file> is located.

=item B<-z>, B<--compress> [I<tool>:]I<level>

Enables compression of archive files with compression level I<level> By
default, the tools bzip2(1), gzip(1) and compress(1) are searched for in
C<$PATH>, but one also can override this by prefixing the compression
level with one of the three particular tool names.

=item B<-b>, B<--background>

Enable background compression.

=item B<-d>, B<--delay>

Delays the compression of archive file number 0. This is useful if
``B<-c>'' is not used, because an application might continue to write to
archive file 0 through an already open file handle.

=item B<-p>, B<--pad> I<len>

Enables padding with leading zeros in the I<number> part of the filename
"I<file>.I<number>I<compress-suffix>". The default padding I<len> is 1.
This is interesting if more than 10 archive files are used, because it
leads to still sorted directory listings.

=item B<-m>, B<--mode> I<mode>

The file mode applied to the created files, see chmod(1). Setting mode to
C<-> skips this step and leaves the operating system default which is
usually based on umask(1). Some file modes require superuser privileges
to be set. Default is 0755.

=item B<-o>, B<--owner> I<owner>

The file owner name or id applied to the created files, see chown(1). This
option requires superuser privileges to execute. Default is to skip this
step and leave the operating system default which is usually based on
the executing uid or the parent setuid directory.

=item B<-g>, B<--group> I<group>

The file group name or id applied to the created files, see chgrp(1). This
option requires superuser privileges to execute to the fullest extend,
otherwise the choice of I<group> is limited on most operating systems.
Default is to skip this step and leave the operating system default
which is usually based on the executing gid or the parent setgid
directory.

=item B<-M>, B<--migrate> I<cmd>

Execute a "migration" command just before the archive file number
I<count>-1 is removed from the filesystem. The specified I<cmd> receives
the archive filename as command line argument.

=item B<-P>, B<--prolog> I<cmd>

Execute a "prolog" command before the rotation step. Useful in
conjunction with B<-s>.

=item B<-E>, B<--epilog> I<cmd>

Execute a "epilog" command after the rotation step. Useful in
conjunction with B<-s>.

=back

=head1 EXAMPLE

#   shell script
 shtool rotate -n10 -s1M -zbzip2:9 -d -r /var/log/ap.access.log
 shtool rotate -n5 -s128K -zbzip2:9 -d -r /var/log/ap.error.log
 apachectl graceful

=head1 HISTORY

The B<GNU shtool> B<rotate> command was originally written by Ralf S.
Engelschall E<lt>rse@engelschall.comE<gt> in 2001 for B<GNU shtool>.
Its development was prompted by the need to have a flexible
logfile rotation facility in the B<OpenPKG> project.

=head1 SEE ALSO

shtool(1), BSD newsyslog(8).

=cut