--- loncom/lcpasswd	2000/10/27 23:32:24	1.4
+++ loncom/lcpasswd	2000/10/29 22:38:21	1.7
@@ -3,7 +3,8 @@
 # lcpasswd
 #
 # Scott Harrison
-# October 27, 2000
+# SH: October 27, 2000
+# SH: October 28, 2000
 
 use strict;
 
@@ -13,6 +14,10 @@ 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
@@ -23,24 +28,25 @@ 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.
 # ( (0,"ok"),
-#   (1,"User ID mismatch.  This program must be run as user 'www'),
+#   (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") )
+#   (3,"Error. Three lines need to be entered into standard input."),
+#   (4,"Error. Too many other simultaneous password change requests being made."),
+#   (5,"Error. User $username does not exist."),
+#   (6,"Error. Invalid entry of current password."),
+#   (7,"Error.  Root was not successfully enabled."),
+#   (8,"Error.  Cannot open /etc/passwd.") )
 
 # Security
-$ENV{'PATH'}="/bin:/usr/bin"; # Nullify path information except for what smbpasswd needs
-$ENV{'BASH_ENV'}=""; # Nullify shell environment information.
+$ENV{'PATH'}='/bin:/usr/bin'; # Nullify path information except for what smbpasswd needs
+$ENV{'BASH_ENV'}=''; # Nullify shell environment information.
 
 # Do not print error messages if there are command-line arguments
 my $noprint=0;
@@ -48,7 +54,8 @@ if (@ARGV) {
     $noprint=1;
 }
 
-open (IN, "</etc/passwd");
+# Read in /etc/passwd, and make sure this process is running from user=www
+open (IN, '</etc/passwd');
 my @lines=<IN>;
 close IN;
 my $wwwid;
@@ -63,6 +70,12 @@ if ($wwwid!=$<) {
 }
 &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 +83,18 @@ 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;
 
@@ -99,28 +109,28 @@ for my $l (@lines) {
 # Verify existence of user
 if (!defined($userid)) {
     print "Error. User $username does not exist.\n" unless $noprint;
-    unlink("/tmp/lock_lcpasswd");
+    unlink('/tmp/lock_lcpasswd');
     exit 5;
 }
 
 # Verify password entry
 if (crypt($oldpwd,$useroldcryptpwd) ne $useroldcryptpwd) {
     print "Error. Invalid entry of current password.\n" unless $noprint;
-    unlink("/tmp/lock_lcpasswd");
+    unlink('/tmp/lock_lcpasswd');
     exit 6;
 }
 
 # Construct new password entry (random salt)
 my $newcryptpwd=crypt($newpwd,(join '', ('.', '/', 0..9, 'A'..'Z', 'a'..'z')[rand 64, rand 64]));
 $U[1]=$newcryptpwd;
-my $userline=join(":",@U);
+my $userline=join(':',@U);
 my $rootid=&enable_root_capability;
 if ($rootid!=0) {
     print "Error.  Root was not successfully enabled.\n" unless $noprint;
-    unlink("/tmp/lock_lcpasswd");
+    unlink('/tmp/lock_lcpasswd');
     exit 7;
 }
-open PASSWORDFILE, ">/etc/passwd" or die("Cannot open /etc/passwd!");
+open PASSWORDFILE, '>/etc/passwd' or (print("Error.  Cannot open /etc/passwd.\n") && unlink('/tmp/lock_lcpasswd') && exit(8));
 for my $l (@lines) {
     @F=split(/\:/,$l);
     if ($F[0] eq $username) {print PASSWORDFILE "$userline\n";}
@@ -130,11 +140,11 @@ close PASSWORDFILE;
 $username=~/^(\w+)$/;
 my $safeusername=$1;
 ($>,$<)=(0,0); # fool smbpasswd here to think this is not a setuid environment
-unless (-e "/etc/smbpasswd") {
-    open (OUT,">/etc/smbpasswd"); close OUT;
+unless (-e '/etc/smbpasswd') {
+    open (OUT,'>/etc/smbpasswd'); close OUT;
 }
 my $smbexist=0;
-open (IN, "</etc/smbpasswd");
+open (IN, '</etc/smbpasswd');
 my @lines=<IN>;
 close IN;
 for my $l (@lines) {
@@ -143,8 +153,8 @@ for my $l (@lines) {
     if ($F[0] eq $username) {$smbexist=1;}
 }
 unless ($smbexist) {
-    open(OUT,">>/etc/smbpasswd");
-    print OUT join(":",($safeusername,$userid,'XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX:XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX','','/home/'.$safeusername,'/bin/bash')) . "\n";
+    open(OUT,'>>/etc/smbpasswd');
+    print OUT join(':',($safeusername,$userid,'XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX:XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX','','/home/'.$safeusername,'/bin/bash')) . "\n";
     close OUT;
 }
 open(OUT,"|/usr/bin/smbpasswd -s $safeusername>/dev/null");
@@ -153,7 +163,7 @@ print OUT $newpwd; print OUT "\n";
 close OUT;
 $<=$wwwid; # unfool the program
 &disable_root_capability;
-unlink("/tmp/lock_lcpasswd");
+unlink('/tmp/lock_lcpasswd');
 exit 0;
 
 # ----------------------------------------------------------- have setuid script run as root
@@ -184,6 +194,15 @@ 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");