--- loncom/lcpasswd	2000/10/27 22:13:40	1.3
+++ loncom/lcpasswd	2000/10/27 23:32:24	1.4
@@ -8,17 +8,46 @@
 use strict;
 
 # This script is a setuid script that should
-# be run by user 'www'.
+# be run by user 'www'.  This script allows
+# for synchronous entry of passwords into
+# both the /etc/passwd and the /etc/smbpasswd
+# files.
 
 # Standard input usage
 # First line is USERNAME
 # Second line is CURRENT PASSWORD
 # Third line is NEW PASSWORD
 
+# Command-line arguments
+# Yes, but be very careful here (don't pass shell commands)
+# and this is only supported to allow perl-system calls.
+
+# Usage within code
+# Note: NEVER run as system("NAME OLDPWD NEWPWD")
+#
+# $exitcode=system("NAME","OLDPWD","NEWPWD")/256;
+# print "uh-oh" if $exitcode;
+
+# These are the exit codes.
+# ( (0,"ok"),
+#   (1,"User ID mismatch.  This program must be run as user 'www'),
+#   (2,"Error. This program does not accept command-line arguments."),
+#   (3,"Error. Three lines need to be entered into standard input.\n"),
+#   (4,"Error. Too many other simultaneous password change requests being made.\n"),
+#   (5,"Error. User $username does not exist.\n"),
+#   (6,"Error. Invalid entry of current password.\n"),
+#   (7,"Error.  Root was not successfully enabled.\n") )
+
 # Security
 $ENV{'PATH'}="/bin:/usr/bin"; # Nullify path information except for what smbpasswd needs
 $ENV{'BASH_ENV'}=""; # Nullify shell environment information.
 
+# Do not print error messages if there are command-line arguments
+my $noprint=0;
+if (@ARGV) {
+    $noprint=1;
+}
+
 open (IN, "</etc/passwd");
 my @lines=<IN>;
 close IN;
@@ -29,29 +58,35 @@ for my $l (@lines) {
     if ($F[0] eq 'www') {$wwwid=$F[2];}
 }
 if ($wwwid!=$<) {
-    print("User ID mismatch.  This program must be run as user 'www'\n");
-    exit 0;
+    print("User ID mismatch.  This program must be run as user 'www'\n") unless $noprint;
+    exit 1;
 }
 &disable_root_capability;
-if (@ARGV) {
-    print("Error. This program does not accept command-line arguments.\n");
-    exit 0;
-}
 
-# Gather input from standard input.  Should only be 3 lines.
-my @input=<>;
-if (@input!=3) {
-    print("Error. Three lines need to be entered into standard input.\n");
-    exit 0;
+# Gather input.  Should only be 3 values.
+my @input;
+if (@ARGV==3) {
+    @input=@ARGV;
+}
+elsif (@ARGV) {
+    print("Error. This program needs 3 command-line arguments (username, old password, new password).\n") unless $noprint;
+    exit 2;
+}
+else {
+    @input=<>;
+    if (@input!=3) {
+	print("Error. Three lines need to be entered into standard input.\n") unless $noprint;
+	exit 3;
+    }
+    map {chop} @input;
 }
-
 # Handle case of another lcpasswd process
 unless (&try_to_lock("/tmp/lock_lcpasswd")) {
-    print "Error. Too many other simultaneous password change requests being made.\n";
-    exit 0;
+    print "Error. Too many other simultaneous password change requests being made.\n" unless $noprint;
+    exit 4;
 }
 
-my ($username,$oldpwd,$newpwd)=map {chop; $_} @input;
+my ($username,$oldpwd,$newpwd)=@input;
 
 # Grab the line corresponding to username
 my ($userid,$useroldcryptpwd);
@@ -63,14 +98,16 @@ for my $l (@lines) {
 
 # Verify existence of user
 if (!defined($userid)) {
-    print "Error. User $username does not exist.\n";
-    exit 0;
+    print "Error. User $username does not exist.\n" unless $noprint;
+    unlink("/tmp/lock_lcpasswd");
+    exit 5;
 }
 
 # Verify password entry
 if (crypt($oldpwd,$useroldcryptpwd) ne $useroldcryptpwd) {
-    print "Error. Invalid entry of current password.\n";
-    exit 0;
+    print "Error. Invalid entry of current password.\n" unless $noprint;
+    unlink("/tmp/lock_lcpasswd");
+    exit 6;
 }
 
 # Construct new password entry (random salt)
@@ -79,8 +116,9 @@ $U[1]=$newcryptpwd;
 my $userline=join(":",@U);
 my $rootid=&enable_root_capability;
 if ($rootid!=0) {
-    print "Error.  Root was not successfully enabled.\n";
-    exit 0;
+    print "Error.  Root was not successfully enabled.\n" unless $noprint;
+    unlink("/tmp/lock_lcpasswd");
+    exit 7;
 }
 open PASSWORDFILE, ">/etc/passwd" or die("Cannot open /etc/passwd!");
 for my $l (@lines) {
@@ -116,7 +154,9 @@ close OUT;
 $<=$wwwid; # unfool the program
 &disable_root_capability;
 unlink("/tmp/lock_lcpasswd");
+exit 0;
 
+# ----------------------------------------------------------- have setuid script run as root
 sub enable_root_capability {
     if ($wwwid==$>) {
 	($<,$>)=($>,$<);
@@ -128,6 +168,7 @@ sub enable_root_capability {
     return $>;
 }
 
+# ----------------------------------------------------------- have setuid script run as www
 sub disable_root_capability {
     if ($wwwid==$<) {
 	($<,$>)=($>,$<);
@@ -138,6 +179,7 @@ sub disable_root_capability {
     }
 }
 
+# ----------------------------------- make sure that another lcpasswd process isn't running
 sub try_to_lock {
     my ($lockfile)=@_;
     my $currentpid;