ruby/lib/tmpdir.rb

# frozen_string_literal: true
#
# tmpdir - retrieve temporary directory path
#
# $Id$
#

require 'fileutils'
begin
  require 'etc.so'
rescue LoadError # rescue LoadError for miniruby
end

class Dir

  @@systmpdir ||= defined?(Etc.systmpdir) ? Etc.systmpdir : '/tmp'

  ##
  # Returns the operating system's temporary file path.

  def self.tmpdir
    if $SAFE > 0
      @@systmpdir.dup
    else
      tmp = nil
      [ENV['TMPDIR'], ENV['TMP'], ENV['TEMP'], @@systmpdir, '/tmp', '.'].each do |dir|
        next if !dir
        dir = File.expand_path(dir)
        if stat = File.stat(dir) and stat.directory? and stat.writable? and
            (!stat.world_writable? or stat.sticky?)
          tmp = dir
          break
        end rescue nil
      end
      raise ArgumentError, "could not find a temporary directory" unless tmp
      tmp
    end
  end

  # Dir.mktmpdir creates a temporary directory.
  #
  # The directory is created with 0700 permission.
  # Application should not change the permission to make the temporary directory accessible from other users.
  #
  # The prefix and suffix of the name of the directory is specified by
  # the optional first argument, <i>prefix_suffix</i>.
  # - If it is not specified or nil, "d" is used as the prefix and no suffix is used.
  # - If it is a string, it is used as the prefix and no suffix is used.
  # - If it is an array, first element is used as the prefix and second element is used as a suffix.
  #
  #  Dir.mktmpdir {|dir| dir is ".../d..." }
  #  Dir.mktmpdir("foo") {|dir| dir is ".../foo..." }
  #  Dir.mktmpdir(["foo", "bar"]) {|dir| dir is ".../foo...bar" }
  #
  # The directory is created under Dir.tmpdir or
  # the optional second argument <i>tmpdir</i> if non-nil value is given.
  #
  #  Dir.mktmpdir {|dir| dir is "#{Dir.tmpdir}/d..." }
  #  Dir.mktmpdir(nil, "/var/tmp") {|dir| dir is "/var/tmp/d..." }
  #
  # If a block is given,
  # it is yielded with the path of the directory.
  # The directory and its contents are removed
  # using FileUtils.remove_entry before Dir.mktmpdir returns.
  # The value of the block is returned.
  #
  #  Dir.mktmpdir {|dir|
  #    # use the directory...
  #    open("#{dir}/foo", "w") { ... }
  #  }
  #
  # If a block is not given,
  # The path of the directory is returned.
  # In this case, Dir.mktmpdir doesn't remove the directory.
  #
  #  dir = Dir.mktmpdir
  #  begin
  #    # use the directory...
  #    open("#{dir}/foo", "w") { ... }
  #  ensure
  #    # remove the directory.
  #    FileUtils.remove_entry dir
  #  end
  #
  def self.mktmpdir(prefix_suffix=nil, *rest)
    base = nil
    path = Tmpname.create(prefix_suffix || "d", *rest) {|path, _, _, d|
      base = d
      mkdir(path, 0700)
    }
    if block_given?
      begin
        yield path
      ensure
        unless base
          stat = File.stat(File.dirname(path))
          if stat.world_writable? and !stat.sticky?
            raise ArgumentError, "parent directory is world writable but not sticky"
          end
        end
        FileUtils.remove_entry path
      end
    else
      path
    end
  end

  module Tmpname # :nodoc:
    module_function

    def tmpdir
      Dir.tmpdir
    end

    UNUSABLE_CHARS = [File::SEPARATOR, File::ALT_SEPARATOR, File::PATH_SEPARATOR, ":"].uniq.join("").freeze

    def create(basename, tmpdir=nil, max_try: nil, **opts)
      if $SAFE > 0 and tmpdir.tainted?
        tmpdir = '/tmp'
      else
        origdir = tmpdir
        tmpdir ||= tmpdir()
      end
      n = nil
      prefix, suffix = basename
      prefix = (String.try_convert(prefix) or
                raise ArgumentError, "unexpected prefix: #{prefix.inspect}")
      prefix = prefix.delete(UNUSABLE_CHARS)
      suffix &&= (String.try_convert(suffix) or
                  raise ArgumentError, "unexpected suffix: #{suffix.inspect}")
      suffix &&= suffix.delete(UNUSABLE_CHARS)
      begin
        t = Time.now.strftime("%Y%m%d")
        path = "#{prefix}#{t}-#{$$}-#{rand(0x100000000).to_s(36)}"\
               "#{n ? %[-#{n}] : ''}#{suffix||''}"
        path = File.join(tmpdir, path)
        yield(path, n, opts, origdir)
      rescue Errno::EEXIST
        n ||= 0
        n += 1
        retry if !max_try or n < max_try
        raise "cannot generate temporary name using `#{basename}' under `#{tmpdir}'"
      end
      path
    end
  end
end