[6370fa6] | 1 | <sect1 id="ch07-functions">
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| 2 | <title>Creating the functions script</title>
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| 3 |
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| 4 | <para>
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[53b5ccf] | 5 | A new file <filename>/etc/init.d/functions</filename> is created containing
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[6370fa6] | 6 | the following:
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| 7 | </para>
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| 8 |
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[3229c6b] | 9 | <para>
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| 10 | <screen>
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[6370fa6] | 11 | <userinput>cat > functions << "EOF"</userinput>
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| 12 | #!/bin/sh
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| 13 | # Begin /etc/init.d/functions
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| 14 |
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| 15 | #
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| 16 | # Set a few variables that influence the text that's printed on the
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| 17 | # screen. The SET_COL variable starts the text in column number 70 (as
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| 18 | # defined by the COL variable). NORMAL prints text in normal mode.
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| 19 | # SUCCESS prints text in a green colour and FAILURE prints text in a red
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| 20 | # colour
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| 21 | #
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| 22 |
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| 23 | COL=70
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[f45bf82] | 24 | WCOL=50
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[6370fa6] | 25 | SET_COL="echo -en \\033[${COL}G"
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[f45bf82] | 26 | SET_WCOL="echo -en \\033[${WCOL}G"
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[6370fa6] | 27 | NORMAL="echo -en \\033[0;39m"
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| 28 | SUCCESS="echo -en \\033[1;32m"
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[f45bf82] | 29 | WARNING="echo -en \\033[1;33m"
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[6370fa6] | 30 | FAILURE="echo -en \\033[1;31m"
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| 31 |
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| 32 | #
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| 33 | # The evaluate_retval function evaluates the return value of the process
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| 34 | # that was run just before this function was called. If the return value
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| 35 | # was 0, indicating success, the print_status function is called with
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| 36 | # the 'success' parameter. Otherwise the print_status function is called
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| 37 | # with the failure parameter.
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| 38 | #
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| 39 |
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| 40 | evaluate_retval()
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| 41 | {
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[d10f4b4] | 42 | if [ $? = 0 ]
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[6370fa6] | 43 | then
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[d10f4b4] | 44 | print_status success
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[6370fa6] | 45 | else
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| 46 | print_status failure
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| 47 | fi
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| 48 | }
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| 49 |
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| 50 | #
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| 51 | # The print_status prints [ OK ] or [FAILED] to the screen. OK appears
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| 52 | # in the colour defined by the SUCCESS variable and FAILED appears in
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| 53 | # the colour defined by the FAILURE variable. Both are printed starting
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[4d994af4] | 54 | # in the column defined by the COL variable.
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[6370fa6] | 55 | #
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| 56 |
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| 57 | print_status()
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| 58 | {
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| 59 |
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| 60 | #
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| 61 | # If no parameters are given to the print_status function, print usage
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| 62 | # information.
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| 63 | #
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| 64 |
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| 65 | if [ $# = 0 ]
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| 66 | then
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| 67 | echo "Usage: print_status {success|failure}"
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| 68 | return 1
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| 69 | fi
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| 70 |
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| 71 | case "$1" in
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| 72 | success)
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| 73 | $SET_COL
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| 74 | echo -n "[ "
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| 75 | $SUCCESS
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| 76 | echo -n "OK"
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| 77 | $NORMAL
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| 78 | echo " ]"
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| 79 | ;;
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[f45bf82] | 80 | warning)
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| 81 | $SET_COL
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| 82 | echo -n "[ "
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| 83 | $WARNING
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| 84 | echo -n "ATTN"
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| 85 | $NORMAL
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| 86 | echo " ]"
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| 87 | ;;
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[6370fa6] | 88 | failure)
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| 89 | $SET_COL
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| 90 | echo -n "["
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| 91 | $FAILURE
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| 92 | echo -n "FAILED"
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| 93 | $NORMAL
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| 94 | echo "]"
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| 95 | ;;
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| 96 | esac
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| 97 |
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| 98 | }
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| 99 |
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| 100 | #
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| 101 | # The loadproc function starts a process (often a daemon) with
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| 102 | # proper error checking
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| 103 | #
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| 104 |
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| 105 | loadproc()
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| 106 | {
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| 107 |
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| 108 | #
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| 109 | # If no parameters are given to the print_status function, print usage
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| 110 | # information.
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| 111 | #
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| 112 |
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| 113 | if [ $# = 0 ]
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| 114 | then
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| 115 | echo "Usage: loadproc {program}"
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| 116 | exit 1
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| 117 | fi
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| 118 | #
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| 119 | # Find the basename of the first parameter (the daemon's name without
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| 120 | # the path
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| 121 | # that was provided so /usr/sbin/syslogd becomes plain 'syslogd' after
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| 122 | # basename ran)
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| 123 | #
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| 124 |
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| 125 | base=$(/usr/bin/basename $1)
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| 126 | #
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| 127 | # the pidlist variable will contains the output of the pidof command.
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| 128 | # pidof will try to find the PID's that belong to a certain string;
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| 129 | # $base in this case
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| 130 | #
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| 131 |
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| 132 | pidlist=$(/bin/pidof -o $$ -o $PPID -o %PPID -x $base)
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| 133 |
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| 134 | pid=""
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| 135 |
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| 136 | for apid in $pidlist
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| 137 | do
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| 138 | if [ -d /proc/$apid ]
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| 139 | then
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| 140 | pid="$pid $apid"
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| 141 | fi
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| 142 | done
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| 143 | #
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| 144 | # If the $pid variable contains anything (from the previous for loop) it
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| 145 | # means the daemon is already running
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| 146 | #
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| 147 |
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| 148 | if [ ! -n "$pid" ]
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| 149 | then
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| 150 | #
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[a2f729c2] | 151 | # Empty $pid variable means it's not running, so we run "$@" (all
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[6370fa6] | 152 | # parameters giving to this function from the script) and then check the
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| 153 | # return value
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| 154 | #
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[f45bf82] | 155 |
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[a2f729c2] | 156 | "$@"
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[6370fa6] | 157 | evaluate_retval
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| 158 | else
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| 159 | #
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[f45bf82] | 160 | # The variable $pid was not empty, meaning it was already running. We'll
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| 161 | # print [ ATTN ] now
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[6370fa6] | 162 | #
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[f45bf82] | 163 |
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| 164 | $SET_WCOL
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| 165 | echo -n "Already running"
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| 166 | print_status warning
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[6370fa6] | 167 | fi
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| 168 |
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| 169 | }
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| 170 |
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| 171 | #
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| 172 | # The killproc function kills a process with proper error checking
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| 173 | #
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| 174 |
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| 175 | killproc()
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| 176 | {
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| 177 |
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| 178 | #
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| 179 | # If no parameters are given to the print_status function, print usage
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| 180 | # information.
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| 181 | #
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| 182 |
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| 183 | if [ $# = 0 ]
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| 184 | then
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| 185 | echo "Usage: killproc {program} [signal]"
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| 186 | exit 1
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| 187 | fi
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| 188 |
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| 189 | #
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| 190 | # Find the basename of the first parameter (the daemon's name without
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| 191 | # the path
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| 192 | # that was provided so /usr/sbin/syslogd becomes plain 'syslogd' after
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| 193 | # basename ran)
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| 194 | #
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| 195 |
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| 196 | base=$(/usr/bin/basename $1)
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| 197 |
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| 198 | #
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| 199 | # Check if we gave a signal to kill the process with (like -HUP, -TERM,
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| 200 | # -KILL, etc) to this function (the second parameter). If no second
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| 201 | # parameter was provided set the nolevel variable. Else set the
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| 202 | # killlevel variable to the value of $2 (the second parameter)
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| 203 | #
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| 204 |
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| 205 | if [ "$2" != "" ]
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| 206 | then
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| 207 | killlevel=-$2
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| 208 | else
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| 209 | nolevel=1
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| 210 | fi
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| 211 |
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| 212 | #
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| 213 | # the pidlist variable will contains the output of the pidof command.
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| 214 | # pidof will try to find the PID's that belong to a certain string;
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| 215 | # $base in this case
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[3d3b466] | 216 | #
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[6370fa6] | 217 |
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| 218 | pidlist=$(/bin/pidof -o $$ -o $PPID -o %PPID -x $base)
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| 219 |
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| 220 | pid=""
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| 221 |
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| 222 | for apid in $pidlist
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| 223 | do
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| 224 | if [ -d /proc/$apid ]
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| 225 | then
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| 226 | pid="$pid $apid"
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| 227 | fi
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| 228 | done
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| 229 |
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| 230 | #
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| 231 | # If $pid contains something from the previous for loop it means one or
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| 232 | # more PID's were found that belongs to the processes to be killed
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| 233 | #
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[f45bf82] | 234 |
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[6370fa6] | 235 | if [ -n "$pid" ]
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| 236 | then
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[f45bf82] | 237 |
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[6370fa6] | 238 | #
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| 239 | # If no kill level was specified we'll try -TERM first and then sleep
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| 240 | # for 2 seconds to allow the kill to be completed
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| 241 | #
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[f45bf82] | 242 |
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[6370fa6] | 243 | if [ "$nolevel" = 1 ]
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| 244 | then
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| 245 | /bin/kill -TERM $pid
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[f45bf82] | 246 |
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[6370fa6] | 247 | #
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[4f3aa1c] | 248 | # If after -TERM the PID still exists we'll wait 2 seconds before
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| 249 | # trying to kill it with -KILL. If the PID still exist after that, wait
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| 250 | # two more seconds. If the PIDs still exist by then it's safe to assume
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| 251 | # that we cannot kill these PIDs.
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[6370fa6] | 252 | #
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[4f3aa1c] | 253 |
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| 254 | if /bin/ps h $pid >/dev/null 2>&1
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[6370fa6] | 255 | then
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[4f3aa1c] | 256 | /usr/bin/sleep 2
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| 257 | if /bin/ps h $pid > /dev/null 2>&1
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| 258 | then
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| 259 | /bin/kill -KILL $pid
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| 260 | if /bin/ps h $pid > /dev/null 2>&1
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| 261 | then
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| 262 | /usr/bin/sleep 2
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| 263 | fi
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| 264 | fi
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[6370fa6] | 265 | fi
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[4f3aa1c] | 266 | /bin/ps h $pid >/dev/null 2>&1
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[6370fa6] | 267 | if [ $? = 0 ]
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| 268 | then
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| 269 | #
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| 270 | # If after the -KILL it still exists it can't be killed for some reason
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| 271 | # and we'll print [FAILED]
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| 272 | #
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[f45bf82] | 273 |
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[6370fa6] | 274 | print_status failure
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| 275 | else
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[f45bf82] | 276 |
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[6370fa6] | 277 | #
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| 278 | # It was killed, remove possible stale PID file in /var/run and
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| 279 | # print [ OK ]
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| 280 | #
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[f45bf82] | 281 |
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[6370fa6] | 282 | /bin/rm -f /var/run/$base.pid
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| 283 | print_status success
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| 284 | fi
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| 285 | else
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[f45bf82] | 286 |
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[6370fa6] | 287 | #
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| 288 | # A kill level was provided. Kill with the provided kill level and wait
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| 289 | # for 2 seconds to allow the kill to be completed
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| 290 | #
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[f45bf82] | 291 |
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[6370fa6] | 292 | /bin/kill $killlevel $pid
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[4f3aa1c] | 293 | if /bin/ps h $pid > /dev/null 2>&1
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| 294 | then
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| 295 | /usr/bin/sleep 2
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| 296 | fi
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| 297 | /bin/ps h $pid >/dev/null 2>&1
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[6370fa6] | 298 | if [ $? = 0 ]
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| 299 | then
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[f45bf82] | 300 |
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[6370fa6] | 301 | #
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| 302 | # If ps' return value is 0 it means it ran ok which indicates that the
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| 303 | # PID still exists. This means the process wasn't killed properly with
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| 304 | # the signal provided. Print [FAILED]
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| 305 | #
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[f45bf82] | 306 |
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[6370fa6] | 307 | print_status failure
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| 308 | else
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[f45bf82] | 309 |
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[6370fa6] | 310 | #
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| 311 | # If the return value was 1 or higher it means the PID didn't exist
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| 312 | # anymore which means it was killed successfully. Remove possible stale
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| 313 | # PID file and print [ OK ]
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| 314 | #
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[f45bf82] | 315 |
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[6370fa6] | 316 | /bin/rm -f /var/run/$base.pid
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| 317 | print_status success
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| 318 | fi
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| 319 | fi
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| 320 | else
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[f45bf82] | 321 |
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[6370fa6] | 322 | #
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[f45bf82] | 323 | # The PID didn't exist so we can't attempt to kill it. Print [ ATTN ]
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[6370fa6] | 324 | #
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[f45bf82] | 325 |
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| 326 | $SET_WCOL
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| 327 | echo -n "Not running"
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| 328 | print_status warning
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[6370fa6] | 329 | fi
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| 330 | }
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| 331 |
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| 332 | #
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| 333 | # The reloadproc functions sends a signal to a daemon telling it to
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| 334 | # reload it's configuration file. This is almost identical to the
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| 335 | # killproc function with the exception that it won't try to kill it with
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| 336 | # a -KILL signal (aka -9)
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| 337 | #
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| 338 |
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| 339 | reloadproc()
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| 340 | {
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| 341 |
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| 342 | #
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| 343 | # If no parameters are given to the print_status function, print usage
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| 344 | # information.
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| 345 | #
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| 346 |
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| 347 | if [ $# = 0 ]
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| 348 | then
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| 349 | echo "Usage: reloadproc {program} [signal]"
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| 350 | exit 1
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| 351 | fi
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| 352 |
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| 353 | #
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| 354 | # Find the basename of the first parameter (the daemon's name without
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[3d3b466] | 355 | # the path that was provided so /usr/sbin/syslogd becomes plain 'syslogd'
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| 356 | # after basename ran)
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[6370fa6] | 357 | #
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| 358 |
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| 359 | base=$(/usr/bin/basename $1)
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| 360 |
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| 361 | #
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| 362 | # Check if we gave a signal to send to the process (like -HUP)
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| 363 | # to this function (the second parameter). If no second
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| 364 | # parameter was provided set the nolevel variable. Else set the
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| 365 | # killlevel variable to the value of $2 (the second parameter)
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| 366 | #
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| 367 |
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| 368 | if [ -n "$2" ]
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| 369 | then
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| 370 | killlevel=-$2
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| 371 | else
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| 372 | nolevel=1
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| 373 | fi
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| 374 |
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| 375 | #
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| 376 | # the pidlist variable will contains the output of the pidof command.
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| 377 | # pidof will try to find the PID's that belong to a certain string;
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| 378 | # $base in this case
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| 379 | #
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| 380 |
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| 381 | pidlist=$(/bin/pidof -o $$ -o $PPID -o %PPID -x $base)
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| 382 |
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| 383 | pid=""
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| 384 |
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| 385 | for apid in $pidlist
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| 386 | do
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| 387 | if [ -d /proc/$apid ]
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| 388 | then
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| 389 | pid="$pid $apid"
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| 390 | fi
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| 391 | done
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| 392 |
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| 393 | #
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| 394 | # If $pid contains something from the previous for loop it means one or
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| 395 | # more PID's were found that belongs to the processes to be reloaded
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| 396 | #
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| 397 |
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| 398 | if [ -n "$pid" ]
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| 399 | then
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| 400 |
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| 401 | #
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| 402 | # If nolevel was set we will use the default reload signal SIGHUP.
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| 403 | #
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| 404 |
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| 405 | if [ "$nolevel" = 1 ]
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| 406 | then
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| 407 | /bin/kill -SIGHUP $pid
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| 408 | evaluate_retval
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| 409 | else
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[f45bf82] | 410 |
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[6370fa6] | 411 | #
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| 412 | # Else we will use the provided signal
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| 413 | #
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| 414 |
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| 415 | /bin/kill $killlevel $pid
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| 416 | evaluate_retval
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| 417 | fi
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| 418 | else
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[f45bf82] | 419 |
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[6370fa6] | 420 | #
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[f45bf82] | 421 | # If $pid is empty no PID's have been found that belong to the process.
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| 422 | # Print [ ATTN ]
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[6370fa6] | 423 | #
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| 424 |
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[f45bf82] | 425 | $SET_WCOL
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| 426 | echo -n "Not running"
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| 427 | print_status warning
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[6370fa6] | 428 | fi
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| 429 | }
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| 430 |
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| 431 | #
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| 432 | # The statusproc function will try to find out if a process is running
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| 433 | # or not
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| 434 | #
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| 435 |
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| 436 | statusproc()
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| 437 | {
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| 438 |
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| 439 | #
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| 440 | # If no parameters are given to the print_status function, print usage
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| 441 | # information.
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| 442 | #
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| 443 |
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| 444 | if [ $# = 0 ]
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| 445 | then
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| 446 | echo "Usage: status {program}"
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| 447 | return 1
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| 448 | fi
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| 449 |
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| 450 | #
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| 451 | # $pid will contain a list of PID's that belong to a process
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| 452 | #
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| 453 |
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| 454 | pid=$(/bin/pidof -o $$ -o $PPID -o %PPID -x $1)
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| 455 | if [ -n "$pid" ]
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| 456 | then
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[f45bf82] | 457 |
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[6370fa6] | 458 | #
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| 459 | # If $pid contains something, the process is running, print the contents
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| 460 | # of the $pid variable
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| 461 | #
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[f45bf82] | 462 |
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[6370fa6] | 463 | echo "$1 running with Process ID $pid"
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| 464 | return 0
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| 465 | fi
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| 466 |
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| 467 | #
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| 468 | # If $pid doesn't contain it check if a PID file exists and inform the
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| 469 | # user about this stale file.
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| 470 | #
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| 471 |
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| 472 | if [ -f /var/run/$1.pid ]
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| 473 | then
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| 474 | pid=$(/usr/bin/head -1 /var/run/$1.pid)
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| 475 | if [ -n "$pid" ]
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| 476 | then
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| 477 | echo "$1 not running but /var/run/$1.pid exists"
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| 478 | return 1
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| 479 | fi
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| 480 | else
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| 481 | echo "$1 is not running"
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| 482 | fi
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| 483 |
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| 484 | }
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| 485 |
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| 486 | # End /etc/init.d/functions
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| 487 | <userinput>EOF</userinput>
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[3229c6b] | 488 | </screen>
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| 489 | </para>
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[6370fa6] | 490 |
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| 491 | </sect1>
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| 492 |
|
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