#!/usr/bin/perl # The CALENDAR Program - answer3.pl # This includes a library module written by Steven Brenner # that allows the use of a nice function called "ReadParse" # that is now part of the CGI Perl Module. uses CGI qw(:cgi-lib :standard); # The function returns a hash of the input from a "CGI form". The # hash keys are the variable names identified in that original form. # The hash values contain the information submitted by the user. &ReadParse(%in); # The following will make a listing of JPEG images in a parallel # directory. The function "srand" will set a seed for a pseudorandom # number generator that will be used later. The web page will # display a random graphic from that directory. srand; # Initialize random number seed $i = 0; while (<../images/*.jpg >) # Loop through all files in other directory { $pictures[$i++] = $_; # Make an array of JPEG image names } $image = $pictures[int(rand($i))]; # Select random file name from set # The next routine attempts to solve a serious security problem # in this program. If the user enters the year, followed by a # semi-colon, another UNIX command can be put on the same line. # After the server finishes running "cal", it will run that other # command also. Potentially evil things could happen! The next # "if" clause scans through the user's input, and if there is a # pattern match for a semi-colon, an alternative page is printed. if ( $in{"year"} =~ ";") {print <

Hello, $in{"name"}! No Calendar today...

ERR } # If the input is "OK", then the "else" clause is executed. This # will run the UNIX command "cal" for the specific month, as well # as the full year, and will display the web page. else{ # The next few lines concatenates month and year into a single string # and use "cal" to generate both monthly and yearly calendars. $date = $in{"month"}." ".$in{"year"}; @calendar = `cal $date`; @year = `cal $in{"year"}`; # From this point forward, the standard HTML code is printed. print<

Hello, $in{"name"}! Here's your monthly calendar...

@calendar

The Full Year $in{"year"}

@year

EOF }