Initial import

8 files changed, 830 insertions, 0 deletions

diff --git a/AUTHORS b/AUTHORS
new file mode 100644
index 0000000..f6b4ec8
--- /dev/null
+++ b/AUTHORS
@@ -0,0 +1,37 @@
+Nate Nielsen <nielsen@memberwebs.com> used vm-pop3d code and gutted it to
+create nullpop.
+
+---------------------------------------------------------------------------
+
+Jeremy C. Reed <reed@reedmedia.net> is the maintainer of virtualmail-pop3d.
+(vm-pop3d is a fork of the gnu-pop3d project.) Previously, he developed
+ten patches for gnu-pop3d which were widely used, but never integrated.
+
+=== The following is the original AUTHORS file for gnu-pop3d 0.9.8 ===
+
+Jakob 'sparky' Kaivo <jkaivo@nodomainname.net> is the original and primary
+author of GNU POP, as well as the maintainer.
+
+Sean 'Shaleh' Perry <shaleh@debian.org> has been invaluable in helping to test
+code and make improvements, including the addition of the CAPA command, the
+idea of using the message struct rather than several different arrays, and
+several memory use issues. He has also helped keep things up to snuff with
+RFCs, and contributed the Debian package stuff and man page. He also looks
+over code before release to make sure I didn't miss anything <g> and lots of
+other work.
+
+Oscar Wahlberg <oscar.wahlberg@connecta.se> contributed APOP and some other
+improvements.
+
+Edgard Castro <castro@usmatrix.net> contributed a much better gnu-pop3d.spec
+file (for RedHat RPM) than the original, as well as a new gnu-pop3d.init script
+and PAM support.
+
+Mike Klinkert <michael@cs.vu.nl> contributed the code for opening alternatvie
+mailboxes (such as might be created by procmail).
+
+Daniel Bergstrom <noa@melody.se> contributed some improvements for PAM support
+and autoconf.
+
+R. Soderberg <occupant@coldflame.net> contributed various autoconf fixes and
+improvements.
diff --git a/CHANGES b/CHANGES
new file mode 100644
index 0000000..ce80146
--- /dev/null
+++ b/CHANGES
@@ -0,0 +1 @@
+0.1 Initial release
diff --git a/COPYING b/COPYING
new file mode 100644
index 0000000..a43ea21
--- /dev/null
+++ b/COPYING
@@ -0,0 +1,339 @@
+		    GNU GENERAL PUBLIC LICENSE
+		       Version 2, June 1991
+
+ Copyright (C) 1989, 1991 Free Software Foundation, Inc.
+                          675 Mass Ave, Cambridge, MA 02139, USA
+ Everyone is permitted to copy and distribute verbatim copies
+ of this license document, but changing it is not allowed.
+
+			    Preamble
+
+  The licenses for most software are designed to take away your
+freedom to share and change it.  By contrast, the GNU General Public
+License is intended to guarantee your freedom to share and change free
+software--to make sure the software is free for all its users.  This
+General Public License applies to most of the Free Software
+Foundation's software and to any other program whose authors commit to
+using it.  (Some other Free Software Foundation software is covered by
+the GNU Library General Public License instead.)  You can apply it to
+your programs, too.
+
+  When we speak of free software, we are referring to freedom, not
+price.  Our General Public Licenses are designed to make sure that you
+have the freedom to distribute copies of free software (and charge for
+this service if you wish), that you receive source code or can get it
+if you want it, that you can change the software or use pieces of it
+in new free programs; and that you know you can do these things.
+
+  To protect your rights, we need to make restrictions that forbid
+anyone to deny you these rights or to ask you to surrender the rights.
+These restrictions translate to certain responsibilities for you if you
+distribute copies of the software, or if you modify it.
+
+  For example, if you distribute copies of such a program, whether
+gratis or for a fee, you must give the recipients all the rights that
+you have.  You must make sure that they, too, receive or can get the
+source code.  And you must show them these terms so they know their
+rights.
+
+  We protect your rights with two steps: (1) copyright the software, and
+(2) offer you this license which gives you legal permission to copy,
+distribute and/or modify the software.
+
+  Also, for each author's protection and ours, we want to make certain
+that everyone understands that there is no warranty for this free
+software.  If the software is modified by someone else and passed on, we
+want its recipients to know that what they have is not the original, so
+that any problems introduced by others will not reflect on the original
+authors' reputations.
+
+  Finally, any free program is threatened constantly by software
+patents.  We wish to avoid the danger that redistributors of a free
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+program proprietary.  To prevent this, we have made it clear that any
+patent must be licensed for everyone's free use or not licensed at all.
+
+  The precise terms and conditions for copying, distribution and
+modification follow.
+
+		    GNU GENERAL PUBLIC LICENSE
+   TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
+
+  0. This License applies to any program or other work which contains
+a notice placed by the copyright holder saying it may be distributed
+under the terms of this General Public License.  The "Program", below,
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+means either the Program or any derivative work under copyright law:
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+either verbatim or with modifications and/or translated into another
+language.  (Hereinafter, translation is included without limitation in
+the term "modification".)  Each licensee is addressed as "you".
+
+Activities other than copying, distribution and modification are not
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+running the Program is not restricted, and the output from the Program
+is covered only if its contents constitute a work based on the
+Program (independent of having been made by running the Program).
+Whether that is true depends on what the Program does.
+
+  1. You may copy and distribute verbatim copies of the Program's
+source code as you receive it, in any medium, provided that you
+conspicuously and appropriately publish on each copy an appropriate
+copyright notice and disclaimer of warranty; keep intact all the
+notices that refer to this License and to the absence of any warranty;
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+along with the Program.
+
+You may charge a fee for the physical act of transferring a copy, and
+you may at your option offer warranty protection in exchange for a fee.
+
+  2. You may modify your copy or copies of the Program or any portion
+of it, thus forming a work based on the Program, and copy and
+distribute such modifications or work under the terms of Section 1
+above, provided that you also meet all of these conditions:
+
+    a) You must cause the modified files to carry prominent notices
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+
+    b) You must cause any work that you distribute or publish, that in
+    whole or in part contains or is derived from the Program or any
+    part thereof, to be licensed as a whole at no charge to all third
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+
+    c) If the modified program normally reads commands interactively
+    when run, you must cause it, when started running for such
+    interactive use in the most ordinary way, to print or display an
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+    notice that there is no warranty (or else, saying that you provide
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+
+These requirements apply to the modified work as a whole.  If
+identifiable sections of that work are not derived from the Program,
+and can be reasonably considered independent and separate works in
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+In addition, mere aggregation of another work not based on the Program
+with the Program (or with a work based on the Program) on a volume of
+a storage or distribution medium does not bring the other work under
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+
+  3. You may copy and distribute the Program (or a work based on it,
+under Section 2) in object code or executable form under the terms of
+Sections 1 and 2 above provided that you also do one of the following:
+
+    a) Accompany it with the complete corresponding machine-readable
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+The source code for a work means the preferred form of the work for
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+If distribution of executable or object code is made by offering
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+distribution of the source code, even though third parties are not
+compelled to copy the source along with the object code.
+
+  4. You may not copy, modify, sublicense, or distribute the Program
+except as expressly provided under this License.  Any attempt
+otherwise to copy, modify, sublicense or distribute the Program is
+void, and will automatically terminate your rights under this License.
+However, parties who have received copies, or rights, from you under
+this License will not have their licenses terminated so long as such
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+
+  5. You are not required to accept this License, since you have not
+signed it.  However, nothing else grants you permission to modify or
+distribute the Program or its derivative works.  These actions are
+prohibited by law if you do not accept this License.  Therefore, by
+modifying or distributing the Program (or any work based on the
+Program), you indicate your acceptance of this License to do so, and
+all its terms and conditions for copying, distributing or modifying
+the Program or works based on it.
+
+  6. Each time you redistribute the Program (or any work based on the
+Program), the recipient automatically receives a license from the
+original licensor to copy, distribute or modify the Program subject to
+these terms and conditions.  You may not impose any further
+restrictions on the recipients' exercise of the rights granted herein.
+You are not responsible for enforcing compliance by third parties to
+this License.
+
+  7. If, as a consequence of a court judgment or allegation of patent
+infringement or for any other reason (not limited to patent issues),
+conditions are imposed on you (whether by court order, agreement or
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+excuse you from the conditions of this License.  If you cannot
+distribute so as to satisfy simultaneously your obligations under this
+License and any other pertinent obligations, then as a consequence you
+may not distribute the Program at all.  For example, if a patent
+license would not permit royalty-free redistribution of the Program by
+all those who receive copies directly or indirectly through you, then
+the only way you could satisfy both it and this License would be to
+refrain entirely from distribution of the Program.
+
+If any portion of this section is held invalid or unenforceable under
+any particular circumstance, the balance of the section is intended to
+apply and the section as a whole is intended to apply in other
+circumstances.
+
+It is not the purpose of this section to induce you to infringe any
+patents or other property right claims or to contest validity of any
+such claims; this section has the sole purpose of protecting the
+integrity of the free software distribution system, which is
+implemented by public license practices.  Many people have made
+generous contributions to the wide range of software distributed
+through that system in reliance on consistent application of that
+system; it is up to the author/donor to decide if he or she is willing
+to distribute software through any other system and a licensee cannot
+impose that choice.
+
+This section is intended to make thoroughly clear what is believed to
+be a consequence of the rest of this License.
+
+  8. If the distribution and/or use of the Program is restricted in
+certain countries either by patents or by copyrighted interfaces, the
+original copyright holder who places the Program under this License
+may add an explicit geographical distribution limitation excluding
+those countries, so that distribution is permitted only in or among
+countries not thus excluded.  In such case, this License incorporates
+the limitation as if written in the body of this License.
+
+  9. The Free Software Foundation may publish revised and/or new versions
+of the General Public License from time to time.  Such new versions will
+be similar in spirit to the present version, but may differ in detail to
+address new problems or concerns.
+
+Each version is given a distinguishing version number.  If the Program
+specifies a version number of this License which applies to it and "any
+later version", you have the option of following the terms and conditions
+either of that version or of any later version published by the Free
+Software Foundation.  If the Program does not specify a version number of
+this License, you may choose any version ever published by the Free Software
+Foundation.
+
+  10. If you wish to incorporate parts of the Program into other free
+programs whose distribution conditions are different, write to the author
+to ask for permission.  For software which is copyrighted by the Free
+Software Foundation, write to the Free Software Foundation; we sometimes
+make exceptions for this.  Our decision will be guided by the two goals
+of preserving the free status of all derivatives of our free software and
+of promoting the sharing and reuse of software generally.
+
+			    NO WARRANTY
+
+  11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY
+FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW.  EXCEPT WHEN
+OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES
+PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED
+OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.  THE ENTIRE RISK AS
+TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU.  SHOULD THE
+PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING,
+REPAIR OR CORRECTION.
+
+  12. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
+WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR
+REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES,
+INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING
+OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED
+TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY
+YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER
+PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGES.
+
+		     END OF TERMS AND CONDITIONS
+
+	Appendix: How to Apply These Terms to Your New Programs
+
+  If you develop a new program, and you want it to be of the greatest
+possible use to the public, the best way to achieve this is to make it
+free software which everyone can redistribute and change under these terms.
+
+  To do so, attach the following notices to the program.  It is safest
+to attach them to the start of each source file to most effectively
+convey the exclusion of warranty; and each file should have at least
+the "copyright" line and a pointer to where the full notice is found.
+
+    <one line to give the program's name and a brief idea of what it does.>
+    Copyright (C) 19yy  <name of author>
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program; if not, write to the Free Software
+    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+Also add information on how to contact you by electronic and paper mail.
+
+If the program is interactive, make it output a short notice like this
+when it starts in an interactive mode:
+
+    Gnomovision version 69, Copyright (C) 19yy name of author
+    Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
+    This is free software, and you are welcome to redistribute it
+    under certain conditions; type `show c' for details.
+
+The hypothetical commands `show w' and `show c' should show the appropriate
+parts of the General Public License.  Of course, the commands you use may
+be called something other than `show w' and `show c'; they could even be
+mouse-clicks or menu items--whatever suits your program.
+
+You should also get your employer (if you work as a programmer) or your
+school, if any, to sign a "copyright disclaimer" for the program, if
+necessary.  Here is a sample; alter the names:
+
+  Yoyodyne, Inc., hereby disclaims all copyright interest in the program
+  `Gnomovision' (which makes passes at compilers) written by James Hacker.
+
+  <signature of Ty Coon>, 1 April 1989
+  Ty Coon, President of Vice
+
+This General Public License does not permit incorporating your program into
+proprietary programs.  If your program is a subroutine library, you may
+consider it more useful to permit linking proprietary applications with the
+library.  If this is what you want to do, use the GNU Library General
+Public License instead of this License.
diff --git a/INSTALL b/INSTALL
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/INSTALL
diff --git a/Makefile.am b/Makefile.am
new file mode 100644
index 0000000..3ab7a5f
--- /dev/null
+++ b/Makefile.am
@@ -0,0 +1,4 @@
+
+libexec_PROGRAMS = nullpop
+
+nullpop_SOURCES = nullpop.c
diff --git a/README b/README
new file mode 100644
index 0000000..00f6fdd
--- /dev/null
+++ b/README
@@ -0,0 +1 @@
+NULLPOP readme
diff --git a/configure.in b/configure.in
new file mode 100644
index 0000000..40e6806
--- /dev/null
+++ b/configure.in
@@ -0,0 +1,39 @@
+
+
+dnl Process this file with autoconf to produce a configure script.
+AC_INIT(nullpop, 0.1, nielsen@memberwebs.com)
+AM_INIT_AUTOMAKE(nullpop, 0.1)
+
+dnl Process this file with autoconf to produce a configure script.
+AC_INIT(nullpop.c)
+
+dnl Checks for programs.
+AC_PROG_CC
+AC_PROG_INSTALL
+AC_PROG_LN_S
+
+dnl Checks for header files.
+AC_HEADER_STDC
+AC_HEADER_SYS_WAIT
+AC_CHECK_HEADERS(fcntl.h limits.h paths.h sys/file.h sys/time.h syslog.h unistd.h)
+
+dnl Checks for typedefs, structures, and compiler characteristics.
+AC_C_CONST
+AC_TYPE_SIZE_T
+AC_HEADER_TIME
+AC_TYPE_UID_T
+
+dnl Checks for library functions.
+AC_FUNC_ALLOCA
+AC_TYPE_SIGNAL
+AC_CHECK_FUNCS(gethostname select socket strdup strerror strstr)
+
+AC_ARG_ENABLE(debug,
+[  --enable-debug      enable debugging messages and logging.],
+[
+AC_MSG_RESULT(debugging enabled)
+AC_DEFINE(DEBUG)
+],)
+
+AC_CONFIG_HEADER(config.h)
+AC_OUTPUT(Makefile)
diff --git a/nullpop.c b/nullpop.c
new file mode 100644
index 0000000..3be7da5
--- /dev/null
+++ b/nullpop.c
@@ -0,0 +1,409 @@
+/* nullpop: A NOOP POP3 Server. Based on:
+
+   virtualmail-pop3d - a POP3 server with virtual domains support
+   This code is licensed under the GPL; it has several authors.
+   vm-pop3d is based on:
+   GNU POP3 - a small, fast, and efficient POP3 daemon
+   Copyright (C) 1999 Jakob 'sparky' Kaivo <jkaivo@nodomainname.net>
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2, or (at your option)
+   any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */
+
+
+#define _GNU_SOURCE
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <signal.h>
+#include <sys/file.h>
+#include <sys/types.h>
+#include <sys/time.h>
+#include <sys/stat.h>
+#include <sys/wait.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <netdb.h>
+#include <pwd.h>
+#include <grp.h>
+#include <syslog.h>
+#include <ctype.h>
+
+/* A command that doesn't exist */
+#define BAD_COMMAND	"Invalid command"
+
+/* Incorrect number of arguments passed to a command */
+#define BAD_ARGS	"Invalid arguments"
+
+/* An action on a message that doesn't exist */
+#define NO_MESG		"No such message"
+
+/* A command that is known but not implemented */
+#define NOT_IMPL	"Not implemented"
+
+/* The command argument was > 40 characters */
+#define TOO_LONG	"Argument too long"
+
+/* Longest legal POP command */
+#define POP_MAXCMDLEN	255
+
+
+
+/* Maximum length of a hostname (is this defined somewhere else?) */
+#ifndef MAXHOSTNAMELEN
+#define MAXHOSTNAMELEN        64
+#endif
+
+#define OK		0
+#define ERR_BAD_ARGS	2
+#define ERR_NO_MESG	4
+#define ERR_NOT_IMPL	5
+#define ERR_BAD_CMD	6
+#define ERR_TOO_LONG	8
+#define ERR_NO_MEM	9
+#define ERR_DEAD_SOCK	10
+#define ERR_SIGNAL	11
+#define ERR_FILE        12
+#define ERR_NO_OFILE    13
+#define ERR_TIMEOUT	14
+
+unsigned int timeout;
+int ifile;
+FILE *ofile;
+
+/* Prints out usage information and exits the program */
+void
+pop3_usage(char *argv0)
+{
+  printf("Usage: %s [OPTIONS]\n", argv0);
+  printf("Runs the nullpop POP3 daemon.\n\n");
+  printf("  -t      sets idle timeout to TIMEOUT seconds\n");
+  exit(2);
+}
+
+/* This is called if it needs to quit without going to the UPDATE stage.
+   This is used for conditions such as out of memory, a broken socket, or
+   being killed on a signal */
+int
+pop3_abquit(int reason)
+{
+  switch (reason) {
+  case ERR_NO_MEM:
+    if (NULL != ofile)
+      fprintf(ofile, "-ERR Out of memory, quitting\r\n");
+    syslog(LOG_ERR, "Out of memory");
+    break;
+  case ERR_DEAD_SOCK:
+    if (NULL != ofile)  /* should this even print to socket? */
+      fprintf(ofile, "-ERR Socket closed, quitting\r\n");
+    syslog(LOG_ERR, "Socket closed");
+    break;
+  case ERR_SIGNAL:
+    if (NULL != ofile)
+      fprintf(ofile, "-ERR Quitting on signal\r\n");
+    break;
+  case ERR_TIMEOUT:
+    if (NULL != ofile)
+      fprintf(ofile, "-ERR Session timed out\r\n");
+    else
+      syslog(LOG_INFO, "Session timed out for no user");
+    break;
+  case ERR_NO_OFILE:
+    syslog(LOG_ERR, "Quitting - couldn't open stream");
+    break;
+  default:
+    if (NULL != ofile)
+      fprintf(ofile, "-ERR Quitting (reason unknown)\r\n");
+    syslog(LOG_ERR, "Unknown quit");
+    break;
+  }
+  fflush(ofile);
+  exit(1);
+}
+
+/* Default signal handler to call the pop3_abquit() function */
+void
+pop3_signal(int signal)
+{
+  syslog(LOG_ERR, "Quitting on signal: %d", signal);
+  pop3_abquit(ERR_SIGNAL);
+}
+
+
+/* Gets a line of input from the client */
+char *
+pop3_readline(int fd)
+{
+  fd_set rfds;
+  struct timeval tv;
+  char buf[1024], *ret = NULL;
+  int available;
+
+  FD_ZERO(&rfds);
+  FD_SET(fd, &rfds);
+  tv.tv_sec = timeout;
+  tv.tv_usec = 0;
+  memset(buf, '\0', 1024);
+
+  while (strchr(buf, '\n') == NULL) {
+    if (timeout > 0) {
+      available = select(fd + 1, &rfds, NULL, NULL, &tv);
+      if (!available)
+	pop3_abquit(ERR_TIMEOUT);
+    }
+    if (read(fd, buf, 1024) < 1)
+      pop3_abquit(ERR_DEAD_SOCK);
+
+    if (ret == NULL) {
+      ret = malloc((strlen(buf) + 1) * sizeof(char));
+      strcpy(ret, buf);
+    } else {
+      ret = realloc(ret, (strlen(ret) + strlen(buf) + 1) * sizeof(char));
+      strcat(ret, buf);
+    }
+  }
+  return ret;
+}
+
+/* Takes a string as input and returns either the remainder of the string
+   after the first space, or a zero length string if no space */
+char *
+pop3_args(const char *cmd)
+{
+  int space = -1, i = 0, len;
+  char *buf;
+
+  len = strlen(cmd) + 1;
+  buf = malloc(len * sizeof(char));
+  if (buf == NULL)
+    pop3_abquit(ERR_NO_MEM);
+
+  while (space < 0 && i < len) {
+    if (cmd[i] == ' ')
+      space = i + 1;
+    else if (cmd[i] == '\0' || cmd[i] == '\r' || cmd[i] == '\n')
+      len = i;
+    i++;
+  }
+
+  if (space < 0)
+    buf[0] = '\0';
+  else {
+    for (i = space; i < len; i++)
+      if (cmd[i] == '\0' || cmd[i] == '\r' || cmd[i] == '\n')
+	buf[i - space] = '\0';
+      else
+	buf[i - space] = cmd[i];
+  }
+
+  return buf;
+}
+
+/* This takes a string and returns the string up to the first space or end of
+   the string, whichever occurs first */
+char *
+pop3_cmd(const char *cmd)
+{
+  char *buf;
+  int i = 0, len;
+
+  len = strlen(cmd) + 1;
+  buf = malloc(len * sizeof(char));
+  if (buf == NULL)
+    pop3_abquit(ERR_NO_MEM);
+
+  for (i = 0; i < len; i++) {
+    if (cmd[i] == ' ' || cmd[i] == '\0' || cmd[i] == '\r' || cmd[i] == '\n')
+      len = i;
+    else
+      buf[i] = cmd[i];
+  }
+  buf[i - 1] = '\0';
+  return buf;
+}
+
+/* The main part of the daemon. This function reads input from the client and
+   executes the proper functions. Also handles the bulk of error reporting. */
+int
+pop3_mainloop(int infile, int outfile)
+{
+  int status = OK;
+  char *buf, *arg, *cmd;
+  struct sockaddr_in name;
+  int namelen = sizeof(name);
+  char *temp_domain;
+
+  ifile = infile;
+  ofile = fdopen(outfile, "w+");
+  if (ofile == NULL)
+    pop3_abquit(ERR_NO_OFILE);
+
+  if (getpeername(infile,
+        (struct sockaddr *) & name, (socklen_t *) & namelen) == 0) {
+    if ((temp_domain = (char *) inet_ntoa(name.sin_addr)))
+      syslog(LOG_INFO,"Connect from %s", temp_domain);
+    else
+      syslog(LOG_INFO, "Connection opened");
+  }
+  else
+    syslog(LOG_INFO, "Incoming connection opened");
+
+  fflush(ofile);
+  fprintf(ofile, "+OK POP3 \r\n");
+
+  for (;;) {
+    fflush(ofile);
+    status = OK;
+    buf = pop3_readline(ifile);
+    cmd = pop3_cmd(buf);
+    arg = pop3_args(buf);
+
+    if (strlen(arg) > POP_MAXCMDLEN || strlen(cmd) > POP_MAXCMDLEN)
+      status = ERR_TOO_LONG;
+    else if (strlen(cmd) > 4)
+      status = ERR_BAD_CMD;
+    else if (strncasecmp(cmd, "USER", 4) == 0) {
+      fprintf(ofile, "+OK\r\n");
+      status = OK;
+    } else if (strncasecmp(cmd, "PASS", 4) == 0) {
+      fprintf(ofile, "+OK\r\n");
+      status = OK;
+    } else if (strncasecmp(cmd, "QUIT", 4) == 0) {
+      fprintf(ofile, "+OK\r\n");
+      fflush(ofile);
+      break;
+    } else if (strncasecmp(cmd, "AUTH", 4) == 0) {
+      status = ERR_NOT_IMPL;
+    } else if (strncasecmp(cmd, "STAT", 4) == 0) {
+      fprintf(ofile, "+OK %d %d\r\n", 0, 0);
+      status = OK;
+    } else if (strncasecmp(cmd, "LIST", 4) == 0) {
+      if (strchr(arg, ' ') != NULL) {
+        status = ERR_BAD_ARGS;
+      } else if (strlen(arg) == 0) {
+        fprintf(ofile, "+OK\r\n");
+        fprintf(ofile, ".\r\n");
+        status = OK;
+      } else {
+        status = ERR_NO_MESG;
+      }
+    } else if (strncasecmp(cmd, "RETR", 4) == 0) {
+      if ((strlen(arg) == 0) || (strchr(arg, ' ') != NULL))
+        status = ERR_BAD_ARGS;
+      else
+        status = ERR_NO_MESG;
+    } else if (strncasecmp(cmd, "DELE", 4) == 0) {
+      if ((strlen(arg) == 0) || (strchr(arg, ' ') != NULL))
+        status = ERR_BAD_ARGS;
+      else
+        status = ERR_NO_MESG;
+    } else if (strncasecmp(cmd, "NOOP", 4) == 0) {
+      if (strlen(arg) != 0)
+        status = ERR_BAD_ARGS;
+      else {
+        fprintf(ofile, "+OK\r\n");
+        status = OK;
+      }
+    } else if (strncasecmp(cmd, "RSET", 4) == 0) {
+      if (strlen(arg) != 0)
+        status = ERR_BAD_ARGS;
+      else {
+        fprintf(ofile, "+OK\r\n");
+        status = OK;
+      }
+    } else if ((strncasecmp(cmd, "TOP", 3) == 0) && (strlen(cmd) == 3)) {
+      status = ERR_NO_MESG;
+    } else if (strncasecmp(cmd, "UIDL", 4) == 0) {
+      if (strchr(arg, ' ') != NULL)
+        status = ERR_BAD_ARGS;
+      else
+        status = ERR_NO_MESG;
+    } else if (strncasecmp(cmd, "CAPA", 4) == 0) {
+      if (strlen(arg) != 0)
+        status = ERR_BAD_ARGS;
+      else {
+        fprintf(ofile, "+OK Capability list follows\r\n");
+        fprintf(ofile, "TOP\r\n");
+        fprintf(ofile, "USER\r\n");
+        fprintf(ofile, "RESP-CODES\r\n");
+        fprintf(ofile, "UIDL\r\n");
+        fprintf(ofile, ".\r\n");
+        status = OK;
+      }
+    } else {
+      status = ERR_BAD_CMD;
+    }
+
+    if (status == OK)
+      fflush(ofile);
+    else if (status == ERR_BAD_ARGS)
+      fprintf(ofile, "-ERR " BAD_ARGS "\r\n");
+    else if (status == ERR_NO_MESG)
+      fprintf(ofile, "-ERR " NO_MESG "\r\n");
+    else if (status == ERR_NOT_IMPL)
+      fprintf(ofile, "-ERR " NOT_IMPL "\r\n");
+    else if (status == ERR_BAD_CMD)
+      fprintf(ofile, "-ERR " BAD_COMMAND "\r\n");
+    else if (status == ERR_TOO_LONG)
+      fprintf(ofile, "-ERR " TOO_LONG "\r\n");
+
+    free(buf);
+    free(cmd);
+    free(arg);
+  }
+
+  fflush(ofile);
+  return OK;
+}
+
+int
+main(int argc, char **argv)
+{
+  int c = 0;
+  timeout = 0;			/* Timeout turned off */
+
+  /* Set the signal handlers */
+  signal(SIGINT, pop3_signal);
+  signal(SIGQUIT, pop3_signal);
+  signal(SIGTERM, pop3_signal);
+
+/* Don't die when a process goes away unexpectedly.
+   Ignore write on a pipe with no reader.  */
+  signal(SIGPIPE, SIG_IGN);
+
+  while ((c = getopt(argc, argv, "t:") && c)) {
+    switch (c) {
+    case 't':
+      timeout = atoi(optarg);
+      break;
+    default:
+      pop3_usage(argv[0]);
+      break;
+    }
+  }
+
+  /* Set up for syslog */
+  openlog("nullpop", LOG_PID, LOG_MAIL);
+
+  pop3_mainloop(fileno(stdin), fileno(stdout));
+
+  /* Close the syslog connection and exit */
+  closelog();
+  return OK;
+}