--- loncom/Attic/lcuseradd	2000/10/29 22:38:21	1.4
+++ loncom/Attic/lcuseradd	2000/10/29 23:14:16	1.7
@@ -20,6 +20,19 @@ use strict;
 # Second line is PASSWORD
 # Third line is PASSWORD
 
+# Valid passwords must consist of the
+# ascii characters within the inclusive
+# range of 0x20 (32) to 0x7E (126).
+# These characters are:
+# SPACE and
+# !"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNO
+# PQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{|}~
+
+# Valid user names must consist of ascii
+# characters that are alphabetical characters
+# (A-Z,a-z), numeric (0-9), or the underscore
+# mark (_). (Essentially, the perl regex \w).
+
 # Command-line arguments [USERNAME] [PASSWORD] [PASSWORD]
 # Yes, but be very careful here (don't pass shell commands)
 # and this is only supported to allow perl-system calls.
@@ -65,7 +78,7 @@ unless (&try_to_lock("/tmp/lock_lcpasswd
 
 # Gather input.  Should be 3 values (user name, password 1, password 2).
 my @input;
-if (@ARGV==1) {
+if (@ARGV==3) {
     @input=@ARGV;
 }
 elsif (@ARGV) {
@@ -75,7 +88,7 @@ elsif (@ARGV) {
 }
 else {
     @input=<>;
-    if (@input!=1) {
+    if (@input!=3) {
 	print("Error. Three lines should be entered into standard input.\n") unless $noprint;
 	unlink('/tmp/lock_lcpasswd');
 	exit 3;
@@ -86,23 +99,104 @@ else {
 my ($username,$password1,$password2)=@input;
 $username=~/^(\w+)$/;
 my $safeusername=$1;
-$password1=~/^(\w+)$/;
-my $password1=$1;
-$password2=~/^(\w+)$/;
-my $safepassword2=$1;
+
+# Only add user if we can create a brand new home directory (/home/username).
+if (-e "/home/$safeusername") {
+    print "Error. User already exists.\n" unless $noprint;
+    unlink('/tmp/lock_lcpasswd');
+    exit 8;
+}
+
+# Only add user if the two password arguments match.
+if ($password1 ne $password2) {
+    print "Error. Password mismatch.\n" unless $noprint;
+    unlink('/tmp/lock_lcpasswd');
+    exit 7;
+}
 
 &enable_root_capability;
 
 # Add user entry to /etc/passwd and /etc/groups in such
 # a way that www is a member of the user-specific group
 
-# This command 'should' make the user be a member of just
-
-if (system('/usr/sbin/useradd','-c','LON-CAPA user','-G','www',$safeusername)) {
-    print "Error.  Something went wrong with the addition of user \"$safeusername\".\n";
+if (system('/usr/sbin/useradd','-c','LON-CAPA user',$safeusername)) {
+    print "Error.  Something went wrong with the addition of user \"$safeusername\".\n" unless $noprint;
     unlink('/tmp/lock_lcpasswd');
     exit 5;
 }
 
-# Set password with lcpasswd (which creates smbpasswd entry).
+# Make www a member of that user group.
+if (system('/usr/sbin/usermod','-G',$safeusername,'www')) {
+    print "Error. Could not make www a member of the group \"$safeusername\".\n" unless $noprint;
+    unlink('/tmp/lock_lcpasswd');
+    exit 6;
+}
+
+# Set password with lcpasswd-style algorithm (which creates smbpasswd entry).
+# I cannot place a direct shell call to lcpasswd since I have to allow
+# for crazy characters in the password, and the setuid environment of perl
+# requires me to make everything safe.
+
+
 
+
+# ----------------------------------------------------------- have setuid script run as root
+sub enable_root_capability {
+    if ($wwwid==$>) {
+	($<,$>)=($>,$<);
+	($(,$))=($),$();
+    }
+    else {
+	# root capability is already enabled
+    }
+    return $>;
+}
+
+# ----------------------------------------------------------- have setuid script run as www
+sub disable_root_capability {
+    if ($wwwid==$<) {
+	($<,$>)=($>,$<);
+	($(,$))=($),$();
+    }
+    else {
+	# root capability is already disabled
+    }
+}
+
+# ----------------------------------- make sure that another lcpasswd process isn't running
+sub try_to_lock {
+    my ($lockfile)=@_;
+    my $currentpid;
+    my $lastpid;
+    # Do not manipulate lock file as root
+    if ($>==0) {
+	return 0;
+    }
+    # Try to generate lock file.
+    # Wait 3 seconds.  If same process id is in
+    # lock file, then assume lock file is stale, and
+    # go ahead.  If process id's fluctuate, try
+    # for a maximum of 10 times.
+    for (0..10) {
+	if (-e $lockfile) {
+	    open(LOCK,"<$lockfile");
+	    $currentpid=<LOCK>;
+	    close LOCK;
+	    if ($currentpid==$lastpid) {
+		last;
+	    }
+	    sleep 3;
+	    $lastpid=$currentpid;
+	}
+	else {
+	    last;
+	}
+	if ($_==10) {
+	    return 0;
+	}
+    }
+    open(LOCK,">$lockfile");
+    print LOCK $$;
+    close LOCK;
+    return 1;
+}