Cookie based login added

    - the cookie last 1 year and is set upon login
    - deleted when pressing "Disconnect" button
    - updated the config.mk and Makefile for COOKIES_DIR variable
    - camel-cased the subroutines. I like it that way, it stands out more
    compared to variables
    - reinserted some vars back into link-tmpl.cgi, it wasn't making sense
    to have them in gpigeon-template.cgi
    - no more 'Unknown' link asker in the links table: if the string is a valid
    email address, we link to the file in the table.

5 files changed, 230 insertions, 129 deletions

diff --git a/Makefile b/Makefile
index 5089417..0799e98 100644
--- a/Makefile
+++ b/Makefile
@@ -14,7 +14,7 @@ install:
 		ARGON2ID_HASH="`tail -1 genpass.txt`"; \
 	fi
 	sed -e 's|argon2id_hash_goes_here|$(ARGON2ID_HASH)|g' -i $(DESTDIR)$(WWWPREFIX)/cgi-bin/gpigeon.cgi
-	sed -e "s|cookies_dir_goes_here|${PREFIX}/cookies|g" -i $(DESTDIR)$(WWWPREFIX)/cgi-bin/gpigeon.cgi
+	sed -e "s|cookies_dir_goes_here|$(COOKIES_DIR)|g" -i $(DESTDIR)$(WWWPREFIX)/cgi-bin/gpigeon.cgi
 	sed -e "s|link_template_path_goes_here|$(LINK_TEMPLATE_PATH)|g" -i $(DESTDIR)$(WWWPREFIX)/cgi-bin/gpigeon.cgi
 	sed -e "s|msg_char_limit_goes_here|$(MSG_FORM_CHAR_LIMIT)|g" -i $(DESTDIR)$(LINK_TEMPLATE_PATH)
 	cp -f link-tmpl.cgi $(DESTDIR)$(LINK_TEMPLATE_PATH)
diff --git a/README.md b/README.md
index 485cf42..873b3d9 100644
--- a/README.md
+++ b/README.md
@@ -1,49 +1,58 @@
 GPIGEON
 ========
 
-Gpigeon generate links for a GPG user to be sent to a non technical person (or
-not a GPG user) so they can send you encrypted mail messages via a one-time
-web link.
+Gpigeon generate links for a non technical person or someone not familiar
+with GPG, so they can send you encrypted mails via a one-time
+web form.
 Feels of déjàvu ? I was inspired by https://hawkpost.co but wasn't really
 interested in the multi-user perspective and managing a database.
 
-Features
+Overview
 ========
 
-    * Single user: no database required.
+    * Single user.
     * One-time GPG form: after sending the encrypted message, the generated form
     self-destructs.
-    * A table of the links generated is visible when you connect so you can
-    keep track. You can also delete link individually or all at once.
+    * Cookie based login. If you block cookies, it will switch back to
+    hidden fields so you can still login, manage and create links.
+    * A table of the links generated is visible after connecting so you can
+    keep track of what has been created. You can also delete links
+    individually, or all at once.
+    * No javascript used for the moment.
 
 Dependencies
 ============
 
-You need perl and the following modules and my perl version is v5.32.0, YMMV:
+You will need perl and the following modules and my perl version is v5.32.0, YMMV:
 
-    * Net:SSLeay
-    * Digest::SHA 
-    * Email::Valid 
-    * String::Random 
     * HTML::Entities
-    * CGI (I'm planning on removing it, I use it just for the
-    convenient param function.) 
-    * CGI::Carp (primarly for debugging, comment the line in
-    gpigeon-template.cgi if you won't need it)
+    * CGI
+    * CGI::Carp
+    * CGI::Cookies
+    * Crypt::Argon2
+    * GPG
+    * Net:SSLeay
     * Net::SMTP
     * Net::SMTPS
-    * GPG
+    * Email::Valid 
+    * String::Random 
 
 Having a webserver with CGI support or a separate CGI engine is needed. I'm using
 nginx and fcgiwrap.
 A note on Net::SMTP and Net:SMTPS dependencies: if you have a mailserver well
-configured with OpenDKIM and the likes (so your chances to get your mail
-treated as spam is greatly reduced) you could replace these two deps with
-Mail::Sendmail then comment and uncomment some lines in <gpigeon-template.cgi>.
+configured with SPF and OpenDKIM (so your chances to get your mail
+treated as spam is greatly reduced) you should set the `HAS_MAILSERVER`
+variable to 1 in the config.mk file.
 
 
 Installation
 ============
 
-Look in the [gpigeon-template.cgi](https://git.les-miquelots.net/gpigeon/plain/gpigeon-template.cgi) source code you should figure things out quickly.
-Hint: look for variables values ending in 'goes_here'.
+Edit the config.mk file to customize the installation to your needs, and then
+execute:
+`sudo make`
+
+You should also look in the
+[gpigeon-template.cgi](https://git.les-miquelots.net/gpigeon/plain/gpigeon-template.cgi)
+and [link-tmpl.cgi](https://git.les-miquelots.net/gpigeon/plain/link-tmpl.cgi) source code, you should figure things out quickly.
+**Hint**: look for variables values ending in _goes_here_.
diff --git a/config.mk b/config.mk
index c722903..abb2299 100644
--- a/config.mk
+++ b/config.mk
@@ -2,6 +2,7 @@
 
 # paths
 PREFIX = /usr/share/webapps/gpigeon
+COOKIES_DIR = $(PREFIX)/cookies
 _GPG_HOMEDIR = $(PREFIX)/gnupg
 LINK_TEMPLATE_PATH = $(PREFIX)/link-tmpl.cgi
 WWWPREFIX = /var/www/gpigeon
diff --git a/gpigeon-template.cgi b/gpigeon-template.cgi
index 277ae0a..5470dfd 100755
--- a/gpigeon-template.cgi
+++ b/gpigeon-template.cgi
@@ -6,23 +6,79 @@ use Crypt::Argon2 qw(argon2id_verify);
 use Email::Valid;
 use String::Random;
 use CGI qw(param);
-#use CGI::Session;
+use CGI::Cookie;
 use CGI::Carp qw(fatalsToBrowser);
 
-sub notif_if_defined{
-    my $notif = shift;
-    if (defined $notif){
-        return $notif;
+sub ValidCookie {
+    my $client_login_cookie = shift;
+    my $dir = shift;
+    if (not defined $client_login_cookie){
+        return;
+    }
+    my $cookie_line = undef;
+    my $filename = $client_login_cookie->value;
+    if ($filename =~ /^([\w]+)$/){
+	    $filename = $1;
+    }
+    else{
+	    return;
+    }
+    my $login_cookiefile = "$dir/$filename.txt";
+    if (-e $login_cookiefile){ 
+        open my $in, '<', $login_cookiefile or die "can't read file: $!";
+        for(1){
+            my $cookie_line = readline $in;
+        }
+        close $in;
+        if (not defined $cookie_line){
+            return;
+        }
     }
     else{
-        return '<!-- undef -->';
+        return;
+    }
+
+    if ($client_login_cookie == $cookie_line){
+        return 1;
+    }
+    return;
+
+}
+
+sub LoginCookieGen {
+    my $id_cookie = shift;
+    my $dir = shift;
+    my $str_rand_obj = String::Random->new;
+    my $val = $str_rand_obj->randregex('\w{64}');
+    my $cookiefile = "$dir/$val.txt";
+    my $new_login_cookie = CGI::Cookie->new(
+        -name  => 'id',
+        -value => $val, 
+        -expires => '+1y',
+        '-max-age' => '+1y',
+        -domain => ".$ENV{'SERVER_NAME'}",
+        -path      => '/',
+        -secure   => 1,
+        -httponly => 1,
+        -samesite => 'Strict',
+    ) or die "Can't create cookie: $!";
+    if (not defined $id_cookie){
+       open my $out, '>', $cookiefile or die "Can't write to $cookiefile: $!";
+       print $out "$new_login_cookie";
+       close $out;
+       print "Set-Cookie: $new_login_cookie\n";
     }
 }
 
-sub untaint_cgi_filename {
+sub EscapeArobase {
+    my $escapedmailaddress = shift;
+    $escapedmailaddress =~ s/@/\\@/;
+    return $escapedmailaddress;
+}
+
+sub UntaintCGIFilename {
     my $filename = shift;
     if ($filename =~ /^([-\@\w.\/]+)$/) {
-        #data untainted
         $filename = $1;
     }
     else {
@@ -32,16 +88,27 @@ sub untaint_cgi_filename {
     return $filename;
 }
 
+sub NotifIfDefined{
+    my $notif = shift;
+    if (defined $notif){
+        return $notif;
+    }
+    else{
+        return '<!--undef notif-->';
+    }
+}
+
+my ($linkgen_notif, $link_asker, $mailisok_notif, $deletion_notif, 
+    $checkedornot, $hidden_pwfield, $id_cookie, 
+    $delete_id_cookie, $idval, $refresh_form) = undef;
+my @created_links = ();
 delete @ENV{qw(IFS PATH CDPATH BASH_ENV)};
 $ENV{'PATH'} = '/usr/bin';
-my $cgi_query_get = CGI->new;
-my @created_links = ();
-my ($linkgen_notif, $mailisok_notif, $deletion_notif) = undef;
-my $LINK_TEMPLATE_PATH='/usr/share/webapps/gpigeon/link-template.pl'; # this is the file where the SMTP and mail address values goes
-my $HOSTNAME = $ENV{'SERVER_NAME'};	
-my $msg_form_char_limit = 3000;
-my $PASSWD_HASH = q{password_hash_goes_here}; #argon2id hash format
-my $PASSWD = $cgi_query_get->param('password');
+my $hostname = $ENV{'SERVER_NAME'};	
+
+my $argon2id_hash       = q{argon2id_hash_goes_here}
+my $cookies_dir         = q{cookies_dir_goes_here};
+my $link_template_path  = q{link_template_path_goes_here};
 
 my %text_strings = (
     addr => 'Address', 
@@ -51,20 +118,20 @@ my %text_strings = (
     create_link_btn => 'Generate link', 
     delete_link_btn_text => 'Delete',
     delete_links_btn_text => 'Delete all links',
-    disconnect_btn_text => 'Disconnect',
+    logout_btn_text => 'Logout',
     here => 'here',
-    link_web_title => 'One time GPG messaging form',
     login => 'Login',
+    link_asker_field_label => q{Asker's mail :},
+    link_web_title => 'One time GPG messaging form',
     link_del_ok => 'Successful removal !',
     link_legend_textarea =>'Type your message below :',
     link_send_btn => 'Send',
-    link_generated_ok => 'Generated a link for',
+    link_ok_for => 'Generated a link for',
     link_del_failed => 'Deletion failed and here is why : ',
-    notif_login_failure => 'Cannot login. Check if your username and password match.'
     mailto_body => 'Your link is ',
     mailto_subject => 'Link to your one time GPG messaging form',
-    msg_too_long => 'Cannot send message : message length must be under ' .$msg_form_char_limit . ' characters.',
-    msg_empty => 'Cannot send message : message is empty. You can type up to ' . $msg_form_char_limit . ' characters.',
+    notif_login_failure => 'Cannot login. Check if your username and password match.'
+    passwd_label => 'Password :',
     refresh_btn_text => 'Refresh',
     type_msg_below => 'Type your message below',
     theader_link => 'Link', 
@@ -73,17 +140,62 @@ my %text_strings = (
     web_title => 'GPIGEON.CGI: generate one time GPG messaging links !', 
     web_greet_msg => 'Hi and welcome.', 
 );
+my $cgi_query_get = CGI->new;
+my $pw = $cgi_query_get->param('password');
+my $logout = $cgi_query_get->param('logout');
+my %cur_cookies = CGI::Cookie->fetch;
+$id_cookie = $cur_cookies{'id'};
+
+if (not defined $id_cookie){
+    $hidden_pwfield = qq{<input type="hidden" name="password" value="$pw">};
+    $refresh_form = qq{<form method="POST">
+                   $hidden_pwfield
+                   <input type="submit" value="$text_strings{refresh_btn_text}">
+                </form>};
+}
+else{
+    $refresh_form = qq{<form method="GET">
+                   <input type="submit" value="$text_strings{refresh_btn_text}">
+                </form>};
+    $idval = $id_cookie->value;
 
-if (argon2id_verify($PASSWD_HASH,$PASSWD)){
-    my $hidden_pwfield = qq{<input type="hidden" name="password" value="$PASSWD">};
+    if ($idval =~ /^([\w]+)$/){
+        $idval = $1;
+    }
+
+    if ($logout){
+        $delete_id_cookie = CGI::Cookie->new(
+            -name  => 'id',
+            -value => $idval, 
+            -expires => '-1d',
+            '-max-age' => '-1d',
+            -domain => ".$hostname",
+            -path      => '/',
+            -secure   => 1,
+            -httponly => 1,
+            -samesite => 'Strict',
+        );
+        my $f = "$cookies_dir/$idval.txt";
+        if (-e "$f"){
+            unlink "$f" or die "Can't delete file :$!";
+        }
+        print "Set-Cookie: $delete_id_cookie\n";
+    }
+}
+
+print "Cache-Control: no-store, must-revalidate\n";
+if (ValidCookie($id_cookie, $cookies_dir) or argon2id_verify($argon2id_hash,$pw)){
+    
+    LoginCookieGen($id_cookie, $cookies_dir);
+    
     if (defined $cgi_query_get->param('supprlien')){
         my $pending_deletion = $cgi_query_get->param('supprlien');
         my $linkfile_fn = "./l/$pending_deletion";
-        if (unlink untaint_cgi_filename($linkfile_fn)){ 
-            $deletion_notif=qq{<span style="color:green">$text_strings{link_del_ok}</span>};
+        if (unlink UntaintCGIFilename($linkfile_fn)){ 
+            $deletion_notif = qq{<span style="color:green">$text_strings{link_del_ok}</span>};
         }
         else {
-            $deletion_notif=qq{<span style="color:red">$text_strings{link_del_failed} $linkfile_fn : $!</span>};
+            $deletion_notif = qq{<span style="color:red">$text_strings{link_del_failed} $linkfile_fn : $!</span>};
         }
     }
 
@@ -91,56 +203,47 @@ if (argon2id_verify($PASSWD_HASH,$PASSWD)){
         opendir my $link_dir_handle, './l' or die "Can't open ./l: $!";
         while (readdir $link_dir_handle) {
             if ($_ ne '.' and $_ ne '..'){
-                my $linkfile_fn = "./l/$_";
-                unlink untaint_cgi_filename($linkfile_fn) or die "$!";
-                $deletion_notif=qq{<span style="color:green">$text_strings{link_del_ok}</span>};
+                unlink UntaintCGIFilename("./l/$_") or die "$!";
+                $deletion_notif = qq{<span style="color:green">$text_strings{link_del_ok}</span>};
             }
         }
         closedir $link_dir_handle;
     }
 
     if (defined $cgi_query_get->param('mail')){
-        my $link_asker = scalar $cgi_query_get->param('mail');
+        $link_asker = scalar $cgi_query_get->param('mail');
 
         if ( Email::Valid->address($link_asker) ){
             $mailisok_notif = qq{<span style="color:green">$text_strings{addr} $link_asker $text_strings{addr_ok}</span>};
-            my $escaped_link_asker = escape_arobase($link_asker);
+            my $escaped_link_asker = EscapeArobase($link_asker);
             my $str_rand_obj = String::Random->new;
-            my $random_fn = $str_rand_obj->randregex('\w{64}');
-            my $GENERATED_FORM_FILENAME = "$random_fn.cgi";
-            my $HREF_LINK   	 = "https://$HOSTNAME/cgi-bin/l/$GENERATED_FORM_FILENAME";
-            my $LINK_PATH 	 =  "./l/$GENERATED_FORM_FILENAME";
+            my $generated_form_filename = $str_rand_obj->randregex('\w{64}') . '.cgi';
+            my $href = "https://$hostname/cgi-bin/l/$generated_form_filename";
+            my $link_path 	 =  "./l/$generated_form_filename";
 
-            open my $in, '<', $LINK_TEMPLATE_PATH or die "Can't read link template file: $!";
-            open my $out, '>', $LINK_PATH or die "Can't write to link file: $!";
+            open my $in, '<', $link_template_path or die "Can't read link template file: $!";
+            open my $out, '>', $link_path or die "Can't write to link file: $!";
             while( <$in> ) {
                 s/{link_user}/{$link_asker}/g;
-                s/{link_filename}/{$GENERATED_FORM_FILENAME}/g;
-                s/{msg_too_long}/$text_strings{msg_too_long}/g;
-                s/{msg_empty}/$text_strings{msg_empty}/g;
-                s/{msg_form_char_limit}/$msg_form_char_limit/g;
                 s/{link_web_title}/$text_strings{link_web_title}/g;
                 s/{link_send_btn}/$text_strings{link_send_btn}/g;
                 s/{type_msg_below}/$text_strings{type_msg_below}/g;
                 print $out $_;
             }
             close $in or die;
-            chmod(0755,$LINK_PATH) or die;
+            chmod(0755,$link_path) or die;
             close $out or die;
-
-            $linkgen_notif = qq{<span style="color:green">$text_strings{link_generated_ok} $link_asker: </span><br><a href="$HREF_LINK">$HREF_LINK</a>};          
+            $linkgen_notif = qq{<span style="color:green">$text_strings{link_ok_for} $link_asker: </span><br><a href="$href">$href</a>};          
         }
         else{
             $mailisok_notif = qq{<span style="color:red">$text_strings{addr} $link_asker $text_strings{addr_nok}.</span>};
         }
     }
-   
 
     opendir my $link_dir_handle, './l' or die "Can't open ./l: $!";
     while (readdir $link_dir_handle) {
         if ($_ ne '.' and $_ ne '..'){
             my $linkfile_fn = $_;
-            my $link_asker = undef;
             if (open my $linkfile_handle , '<', "./l/$linkfile_fn"){
                 for (1..2){
                     $link_asker = readline $linkfile_handle;
@@ -149,23 +252,20 @@ if (argon2id_verify($PASSWD_HASH,$PASSWD)){
                 }
                 close $linkfile_handle;
                 
-                if (not defined $link_asker){
-                    $link_asker = $text_strings{unknown};
+                if (Email::Valid->address($link_asker){
+                    push @created_links,
+                    qq{<tr>
+                        <td><a href="/cgi-bin/l/$linkfile_fn">$text_strings{here}</a></td>
+                        <td><a href="mailto:$link_asker?subject=$text_strings{mailto_subject}&body=$text_strings{mailto_body} http://$hostname/cgi-bin/l/$linkfile_fn">$link_asker</a></td>
+                        <td>
+                            <form method="POST">
+                                $hidden_pwfield
+                                <input type="hidden" name="supprlien" value="$linkfile_fn">
+                                <input type="submit" value="$text_strings{delete_link_btn_text}">
+                            </form>
+                        </td>
+                    </tr>};
                 }
-                #create links table html
-                push @created_links,
-                qq{<tr>
-                    <td><a href="/cgi-bin/l/$linkfile_fn">ici</a></td>
-                    <td><a href="mailto:$link_asker?subject=$text_strings{mailto_subject}&body=$text_strings{mailto_body} http://$HOSTNAME/cgi-bin/l/$linkfile_fn">$link_asker</a></td>
-                    <td>
-                        <form method="POST">
-                            <input type="hidden" name="supprlien" value="$linkfile_fn">
-                            <input type="hidden" name="password" value="$PASSWD">
-                            <input type="submit" value="$text_strings{delete_link_btn_text}">
-                        </form>
-                    </td>
-                </tr>};
-
             }
             else {
                 close $linkfile_handle;
@@ -187,32 +287,29 @@ if (argon2id_verify($PASSWD_HASH,$PASSWD)){
             </head>
             <body>
                 <p>$text_strings{web_greet_msg}</p>
-                <form method="POST">
-                    <input type="hidden" name="password" value="0">
-                    <input type="submit" value="$text_strings{disconnect_btn_text}">
-                </form>
-                <form method="POST">
-                $hidden_pwfield
-                   <input type="submit" value="$text_strings{refresh_btn_text}">
+                <form method="GET">
+                    <input type="hidden" name="logout" value="1">
+                    <input type="submit" value="$text_strings{logout_btn_text}">
                 </form>
+                $refresh_form
                 <hr>
                 <br>
                 <form method="POST">
                     $hidden_pwfield
-                    Mail de la personne:<br>
+                    $text_strings{link_asker_field_label}<br>
                     <input tabindex="1" type="text" name="mail">
                     <input tabindex="2" type="submit" value="$text_strings{create_link_btn}">
                 </form>},
-                notif_if_defined($mailisok_notif),
+                NotifIfDefined($mailisok_notif),
                 '<br>',
-                notif_if_defined($linkgen_notif),
+                NotifIfDefined($linkgen_notif),
                 qq{<hr>
                 <form method="POST">
                     $hidden_pwfield
                     <input type="hidden" name="supprtout">
                      <input type="submit" value="$text_strings{delete_links_btn_text}">
                 </form>},
-                notif_if_defined($deletion_notif),
+                NotifIfDefined($deletion_notif),
                 qq{<table>
                     <tr>
                         <th>$text_strings{theader_link}</th>
@@ -224,8 +321,8 @@ if (argon2id_verify($PASSWD_HASH,$PASSWD)){
             </body>
         </html>};
 }
-else {
-    print 'Content-type: text/html',"\n\n",
+else{
+    print "Content-Type: text/html\n\n",
     qq{<!DOCTYPE html>
     <html>
         <head>
@@ -236,21 +333,14 @@ else {
         </head>
         <body>
             <form action="/cgi-bin/gpigeon.cgi" method="POST">
-            <h1 style="text-align:center">GPIGEON</h1>
-            Mot de passe : <input type="password" name="password"><br>
+            <h1>GPIGEON</h1>
+	    <label for="pwfield">&nbsp;$text_strings{passwd_label}:</label>
+            <input id="pwfield" type="password" name="password"><br>
             <input type="submit" value="$text_strings{login}">
             </form>
-
-            <p><a
+            <p>&nbsp;<a
             href="http://git.les-miquelots.net/gpigeon"
             title="gpigeon download link" alt="gpigeon download link">Source code here.</a> It is similar to <a href="https://hawkpost.co/">hawkpost.co</a>.</p>
-
-            <a href="https://xkcd.com/538"><img id="crypto_secu"
-            src="security.png" title="XKCD fait redescendre les nerds du
-            chiffrement sur terre (xkcd.com/538)" alt="BD de XKCD faisant redescendre les
-            nerds du chiffrement sur terre"></a>
-
         </body>
-
     </html>};
 }
diff --git a/link-tmpl.cgi b/link-tmpl.cgi
index 2c51268..b2fe3b3 100644
--- a/link-tmpl.cgi
+++ b/link-tmpl.cgi
@@ -1,7 +1,5 @@
 #! /usr/bin/perl -wT
 my $linkuser = q{link_user};
-my $linkfilename = q{link_filename};
-
 use warnings;
 use strict;
 use GPG;
@@ -10,30 +8,31 @@ use CGI qw(param);
 $ENV{'PATH'}="/usr/bin";
 delete @ENV{qw(IFS PATH CDPATH BASH_ENV)};
 
-sub escape_arobase {
+sub EscapeArobase {
     my $escapedmailaddress = shift;
     $escapedmailaddress =~ s/@/\\@/;
     return $escapedmailaddress;
 }
 
-my $HAS_MAILSERVER = 0;
-my $mymailaddr = q{your mail address goes here};
-my $mymail_gpgid = q{your gpg id in the 0xlong form goes here}; #0xlong keyid form
-my $mailsender = q{mail address sending encrypted text goes here. recommended to be different from $mymailaddr};
-my $mailsender_smtp = q{your SMTP mail domain name goes here};
-my $mailsender_port = q{your SMTP port goes here};
-my $mailsender_pw = q{password for $mailsender address goes here};
-my $GPG_HOMEDIR = '/usr/share/webapps/gpigeon/gnupg/';
+my $HAS_MAILSERVER = q{has_mailserver_goes_here};
+my $msg_form_char_limit = q{msg_char_limit_goes_here};
+my $mymailaddr = q{your_addr_goes_here};
+my $mymail_gpgid = q{gpgid_goes_here}; #0xlong keyid form
+my $mailsender = q{sender_addr_goes_here};
+my $mailsender_smtp = q{smtp_domain_goes_here};
+my $mailsender_port = q{smtp_port_goes_here};
+my $mailsender_pw = q{sender_pw_goes_here};
+my $GPG_HOMEDIR = q{gpg_homedir_goes_here};
 my $cgi_query_get = CGI->new;
 my $msg_form = $cgi_query_get->param('msg');
 my $length_msg_form = length $msg_form;
 my ($enc_msg, $error_processing_msg) = undef;
 
-if (defined $length_msg_form and $length_msg_form > {msg_form_char_limit}){
-    $error_processing_msg = q{<span style="color:red"><b>{msg_too_long}</b></span>};
+if (defined $length_msg_form and $length_msg_form > $msg_form_char_limit){
+    $error_processing_msg = qq{<span style="color:red"><b>Cannot send message : message length must be under $msg_form_char_limit characters.</b></span>};
 } 
 elsif (defined $length_msg_form and $length_msg_form eq 0 ){
-    $error_processing_msg = q{<span style="color:red"><b>{msg_empty}</b></span>};
+    $error_processing_msg = qq{<span style="color:red"><b>Cannot send message : message is empty. You can type up to $msg_form_char_limit characters.</b></span>};
 }
 else {
     if (defined $length_msg_form and $ENV{REQUEST_METHOD} eq 'POST'){
@@ -55,8 +54,8 @@ else {
            use Net::SMTP;
            use Net::SMTPS;
            my $smtp = Net::SMTPS->new($mailsender_smtp, Port => $mailsender_port, doSSL => 'ssl', Debug_SSL => 0); 
-           my $mymailaddr_escaped = escape_arobase{$mymailaddr};
-           my $mailsender_escaped = escape_arobase($mailsender);
+           my $mymailaddr_escaped = EscapeArobase{$mymailaddr};
+           my $mailsender_escaped = EscapeArobase($mailsender);
 
            $smtp->auth($mailsender, $mailsender_pw) or die;
            $smtp->mail($mailsender) or die "Net::SMTP module has broke: $!.";
@@ -72,8 +71,10 @@ else {
            else {
               die $smtp->message();
            }
-
-           unlink "../l/$linkfilename";
+           my $f = $0;
+           if ($f =~ /^([\w]+)$/){
+               unlink "$1";
+           }
            print "Location: /merci/index.html\n\n"; 
        }
    }
@@ -91,7 +92,7 @@ print qq{<!DOCTYPE html>
     <body>
         <p>{type_msg_below}:</p>
             <form method="POST">
-                <textarea wrap="off" cols="50" rows="30" name="msg"></textarea><br>
+                <textarea id="msg" wrap="off" cols="50" rows="30" name="msg"></textarea><br>
 };
 if (defined $error_processing_msg){
     printf $error_processing_msg;