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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5 | A new file <filename>/etc/init.d/functions</filename> is created containing
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6 | the following:
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7 | </para>
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8 |
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9 | <para>
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10 | <screen>
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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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24 | WCOL=50
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25 | SET_COL="echo -en \\033[${COL}G"
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26 | SET_WCOL="echo -en \\033[${WCOL}G"
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27 | NORMAL="echo -en \\033[0;39m"
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28 | SUCCESS="echo -en \\033[1;32m"
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29 | WARNING="echo -en \\033[1;33m"
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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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42 | if [ $? = 0 ]
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43 | then
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44 | print_status success
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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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54 | # in the column defined by the COL variable.
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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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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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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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151 | # Empty $pid variable means it's not running, so we run "$@" (all
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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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155 |
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156 | "$@"
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157 | evaluate_retval
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158 | else
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159 | #
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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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162 | #
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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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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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216 | #
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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 $pid contains something from the previous for loop it means one or
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232 | # more PID's were found that belongs to the processes to be killed
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233 | #
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234 |
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235 | if [ -n "$pid" ]
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236 | then
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237 |
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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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242 |
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243 | if [ "$nolevel" = 1 ]
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244 | then
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245 | /bin/kill -TERM $pid
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246 |
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247 | #
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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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252 | #
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253 |
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254 | if /bin/ps h $pid >/dev/null 2>&1
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255 | then
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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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265 | fi
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266 | /bin/ps h $pid >/dev/null 2>&1
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267 | if [ $? = 0 ]
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268 | then
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269 | #
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270 | # If after the -KILL it still exists it can't be killed for some reason
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271 | # and we'll print [FAILED]
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272 | #
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273 |
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274 | print_status failure
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275 | else
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276 |
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277 | #
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278 | # It was killed, remove possible stale PID file in /var/run and
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279 | # print [ OK ]
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280 | #
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281 |
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282 | /bin/rm -f /var/run/$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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286 |
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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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291 |
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292 | /bin/kill $killlevel $pid
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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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298 | if [ $? = 0 ]
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299 | then
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300 |
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301 | #
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302 | # If ps' return value is 0 it means it ran ok which indicates that the
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303 | # PID still exists. This means the process wasn't killed properly with
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304 | # the signal provided. Print [FAILED]
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305 | #
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306 |
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307 | print_status failure
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308 | else
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309 |
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310 | #
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311 | # If the return value was 1 or higher it means the PID didn't exist
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312 | # anymore which means it was killed successfully. Remove possible stale
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313 | # PID file and print [ OK ]
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314 | #
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315 |
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316 | /bin/rm -f /var/run/$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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321 |
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322 | #
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323 | # The PID didn't exist so we can't attempt to kill it. Print [ ATTN ]
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324 | #
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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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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 [ $# = 0 ]
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348 | then
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349 | echo "Usage: reloadproc {program} [signal]"
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350 | exit 1
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351 | fi
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352 |
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353 | #
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354 | # Find the basename of the first parameter (the daemon's name without
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355 | # the path that was provided so /usr/sbin/syslogd becomes plain 'syslogd'
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356 | # after basename ran)
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357 | #
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358 |
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359 | base=$(/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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410 |
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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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419 |
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420 | #
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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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423 | #
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424 |
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425 | $SET_WCOL
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426 | echo -n "Not running"
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427 | print_status warning
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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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457 |
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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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462 |
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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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488 | </screen>
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489 | </para>
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490 |
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491 | </sect1>
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492 |
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