--- loncom/lcpasswd	2000/10/27 23:32:24	1.4
+++ loncom/lcpasswd	2000/10/28 18:25:47	1.5
@@ -13,6 +13,10 @@ use strict;
 # both the /etc/passwd and the /etc/smbpasswd
 # files.
 
+# This script works under the same process control mechanism
+# as lcuseradd and lcpasswd, to make sure that only one of these
+# processes is running at any one time on the system.
+
 # Standard input usage
 # First line is USERNAME
 # Second line is CURRENT PASSWORD
@@ -23,9 +27,9 @@ use strict;
 # and this is only supported to allow perl-system calls.
 
 # Usage within code
-# Note: NEVER run as system("NAME OLDPWD NEWPWD")
+# Note: NEVER run as system("/home/httpd/perl/lcpasswd NAME OLDPWD NEWPWD")
 #
-# $exitcode=system("NAME","OLDPWD","NEWPWD")/256;
+# $exitcode=system("/home/httpd/perl/lcpasswd","NAME","OLDPWD","NEWPWD")/256;
 # print "uh-oh" if $exitcode;
 
 # These are the exit codes.
@@ -48,6 +52,7 @@ if (@ARGV) {
     $noprint=1;
 }
 
+# Read in /etc/passwd, and make sure this process is running from user=www
 open (IN, "</etc/passwd");
 my @lines=<IN>;
 close IN;
@@ -59,10 +64,17 @@ for my $l (@lines) {
 }
 if ($wwwid!=$<) {
     print("User ID mismatch.  This program must be run as user 'www'\n") unless $noprint;
+    unlink("/tmp/lock_lcpasswd");
     exit 1;
 }
 &disable_root_capability;
 
+# 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" unless $noprint;
+    exit 4;
+}
+
 # Gather input.  Should only be 3 values.
 my @input;
 if (@ARGV==3) {
@@ -70,21 +82,18 @@ if (@ARGV==3) {
 }
 elsif (@ARGV) {
     print("Error. This program needs 3 command-line arguments (username, old password, new password).\n") unless $noprint;
+    unlink("/tmp/lock_lcpasswd");
     exit 2;
 }
 else {
     @input=<>;
     if (@input!=3) {
 	print("Error. Three lines need to be entered into standard input.\n") unless $noprint;
+	unlink("/tmp/lock_lcpasswd");
 	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" unless $noprint;
-    exit 4;
-}
 
 my ($username,$oldpwd,$newpwd)=@input;
 
@@ -184,6 +193,15 @@ 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");