amahi/platform

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lib/system_utils.rb

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# Amahi Home Server
# Copyright (C) 2007-2013 Amahi
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License v3
# (29 June 2007), as published in the COPYING file.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# file COPYING for more details.
#
# You should have received a copy of the GNU General Public
# License along with this program; if not, write to the Amahi
# team at http://www.amahi.org/ under "Contact Us."


class SystemUtils
    def self.uptime
        self.run "uptime"
    end

    def self.run (cmd)
        pipe = IO.popen(cmd)
        ret = pipe.read
        pipe.close
        ret
    end

    def self.run_script(script, name, environment = {})
        require 'tempfile'
        include Process

        # number of linear backoff steps to wait. 22 ~= 160s
        steps = 25
        # duration of the base step for the sleep checks
        base_duration = 0.5
        f = Tempfile.new "run_script"
        File.chmod(0700, f.path)
        f.write(script)
        f.close
        ret = 0
        pid = fork
        unless pid
            # child
            environment.each_pair { |k,v| ENV[k] =v }
            if script[0..1] =~ /^#!/
                exec("#{f.path} #{name} 2>&1")
            else
                exec("bash #{f.path} #{name} 2>&1")
            end
        else
            # parent
            i = 1
            status = nil
            done = false
            until done
                sleep(base_duration * i)
                i+=1
                (x, status) = Process.waitpid2(pid, Process::WNOHANG)
                done = status.nil? ? (i > steps) : true
            end
            # if status is still nil, we have to kill the process
            unless status
                Process.kill("KILL", pid)
                raise "run_script had to KILL this script. it was taking too long. sorry."
            else
                ret = status.exitstatus
            end
        end
    end

    def self.unpack(url, fname)
        if (url =~ /\.zip$/)
            system("unzip -q #{fname}")
        elsif (url =~ /\.(tar.gz|tgz)$/)
            system("tar -xzf #{fname}")
        elsif (url =~ /\.(tar.bz2)$/)
            system("tar -xjf #{fname}")
        else
            raise "File #{url} is not supported for unpacking please report it to the Amahi community!"
        end
    end

end