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