root/trunk/lib-src/pop.c

/* pop.c: client routines for talking to a POP3-protocol post-office server
   Copyright (C) 1991, 1993, 1996, 1997, 1999, 2001, 2002, 2003, 2004,
                 2005, 2006, 2007, 2008  Free Software Foundation, Inc.
   Written by Jonathan Kamens, jik@security.ov.com.

This file is part of GNU Emacs.

GNU Emacs 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 3, or (at your option)
any later version.

GNU Emacs 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 GNU Emacs; see the file COPYING.  If not, write to
the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
Boston, MA 02110-1301, USA.  */

#ifdef HAVE_CONFIG_H
#define NO_SHORTNAMES   /* Tell config not to load remap.h */
#include <config.h>
#else
#define MAIL_USE_POP
#endif

#ifdef MAIL_USE_POP

#include <sys/types.h>
#ifdef WINDOWSNT
#include "ntlib.h"
#include <winsock.h>
#undef SOCKET_ERROR
#define RECV(s,buf,len,flags) recv(s,buf,len,flags)
#define SEND(s,buf,len,flags) send(s,buf,len,flags)
#define CLOSESOCKET(s) closesocket(s)
#else
#include <netinet/in.h>
#include <sys/socket.h>
#define RECV(s,buf,len,flags) read(s,buf,len)
#define SEND(s,buf,len,flags) write(s,buf,len)
#define CLOSESOCKET(s) close(s)
#endif
#include <pop.h>

#ifdef sun
#include <malloc.h>
#endif /* sun */

#ifdef HESIOD
#include <hesiod.h>
/*
 * It really shouldn't be necessary to put this declaration here, but
 * the version of hesiod.h that Athena has installed in release 7.2
 * doesn't declare this function; I don't know if the 7.3 version of
 * hesiod.h does.
 */
extern struct servent *hes_getservbyname (/* char *, char * */);
#endif

#include <pwd.h>
#include <netdb.h>
#include <errno.h>
#include <stdio.h>
#ifdef STDC_HEADERS
#include <string.h>
#define index strchr
#endif
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif

#ifdef KERBEROS
# ifdef HAVE_KRB5_H
#  include <krb5.h>
# endif
# ifdef HAVE_KRB_H
#  include <krb.h>
# else
#  ifdef HAVE_KERBEROSIV_KRB_H
#   include <kerberosIV/krb.h>
#  else
#   ifdef HAVE_KERBEROS_KRB_H
#    include <kerberos/krb.h>
#   endif
#  endif
# endif
# ifdef HAVE_COM_ERR_H
#  include <com_err.h>
# endif
#endif /* KERBEROS */

#ifdef KERBEROS
#ifndef KERBEROS5
extern int krb_sendauth (/* long, int, KTEXT, char *, char *, char *,
                            u_long, MSG_DAT *, CREDENTIALS *, Key_schedule,
                            struct sockaddr_in *, struct sockaddr_in *,
                            char * */);
extern char *krb_realmofhost (/* char * */);
#endif /* ! KERBEROS5 */
#endif /* KERBEROS */

#ifndef WINDOWSNT
#if !defined(HAVE_H_ERRNO) || !defined(HAVE_CONFIG_H)
extern int h_errno;
#endif
#endif

#ifndef __P
# ifdef __STDC__
#  define __P(a) a
# else
#  define __P(a) ()
# endif /* __STDC__ */
#endif /* ! __P */

static int socket_connection __P((char *, int));
static int pop_getline __P((popserver, char **));
static int sendline __P((popserver, char *));
static int fullwrite __P((int, char *, int));
static int getok __P((popserver));
#if 0
static int gettermination __P((popserver));
#endif
static void pop_trash __P((popserver));
static char *find_crlf __P((char *, int));

#define ERROR_MAX 160           /* a pretty arbitrary size, but needs
                                   to be bigger than the original
                                   value of 80 */
#define POP_PORT 110
#define KPOP_PORT 1109
#define POP_SERVICE "pop3"      /* we don't want the POP2 port! */
#ifdef KERBEROS
#define KPOP_SERVICE "kpop"     /* never used: look for 20060515 to see why */
#endif

char pop_error[ERROR_MAX];
int pop_debug = 0;

#ifndef min
#define min(a,b) (((a) < (b)) ? (a) : (b))
#endif

/*
 * Function: pop_open (char *host, char *username, char *password,
 *                     int flags)
 *
 * Purpose: Establishes a connection with a post-office server, and
 *      completes the authorization portion of the session.
 *
 * Arguments:
 *      host    The server host with which the connection should be
 *              established.  Optional.  If omitted, internal
 *              heuristics will be used to determine the server host,
 *              if possible.
 *      username
 *              The username of the mail-drop to access.  Optional.
 *              If omitted, internal heuristics will be used to
 *              determine the username, if possible.
 *      password
 *              The password to use for authorization.  If omitted,
 *              internal heuristics will be used to determine the
 *              password, if possible.
 *      flags   A bit mask containing flags controlling certain
 *              functions of the routine.  Valid flags are defined in
 *              the file pop.h
 *
 * Return value: Upon successful establishment of a connection, a
 *      non-null popserver will be returned.  Otherwise, null will be
 *      returned, and the string variable pop_error will contain an
 *      explanation of the error.
 */
popserver
pop_open (host, username, password, flags)
     char *host;
     char *username;
     char *password;
     int flags;
{
  int sock;
  popserver server;

  /* Determine the user name */
  if (! username)
    {
      username = getenv ("USER");
      if (! (username && *username))
        {
          username = getlogin ();
          if (! (username && *username))
            {
              struct passwd *passwd;
              passwd = getpwuid (getuid ());
              if (passwd && passwd->pw_name && *passwd->pw_name)
                {
                  username = passwd->pw_name;
                }
              else
                {
                  strcpy (pop_error, "Could not determine username");
                  return (0);
                }
            }
        }
    }

  /*
   *  Determine the mail host.
   */

  if (! host)
    {
      host = getenv ("MAILHOST");
    }

#ifdef HESIOD
  if ((! host) && (! (flags & POP_NO_HESIOD)))
    {
      struct hes_postoffice *office;
      office = hes_getmailhost (username);
      if (office && office->po_type && (! strcmp (office->po_type, "POP"))
          && office->po_name && *office->po_name && office->po_host
          && *office->po_host)
        {
          host = office->po_host;
          username = office->po_name;
        }
    }
#endif

#ifdef MAILHOST
  if (! host)
    {
      host = MAILHOST;
    }
#endif

  if (! host)
    {
      strcpy (pop_error, "Could not determine POP server");
      return (0);
    }

  /* Determine the password */
#ifdef KERBEROS
#define DONT_NEED_PASSWORD (! (flags & POP_NO_KERBEROS))
#else
#define DONT_NEED_PASSWORD 0
#endif

  if ((! password) && (! DONT_NEED_PASSWORD))
    {
      if (! (flags & POP_NO_GETPASS))
        {
          password = getpass ("Enter POP password:");
        }
      if (! password)
        {
          strcpy (pop_error, "Could not determine POP password");
          return (0);
        }
    }
  if (password)                 /* always true, detected 20060515 */
    flags |= POP_NO_KERBEROS;
  else
    password = username;        /* dead code, detected 20060515 */
  /** "kpop" service is  never used: look for 20060515 to see why **/

  sock = socket_connection (host, flags);
  if (sock == -1)
    return (0);

  server = (popserver) malloc (sizeof (struct _popserver));
  if (! server)
    {
      strcpy (pop_error, "Out of memory in pop_open");
      return (0);
    }
  server->buffer = (char *) malloc (GETLINE_MIN);
  if (! server->buffer)
    {
      strcpy (pop_error, "Out of memory in pop_open");
      free ((char *) server);
      return (0);
    }

  server->file = sock;
  server->data = 0;
  server->buffer_index = 0;
  server->buffer_size = GETLINE_MIN;
  server->in_multi = 0;
  server->trash_started = 0;

  if (getok (server))
    return (0);

  /*
   * I really shouldn't use the pop_error variable like this, but....
   */
  if (strlen (username) > ERROR_MAX - 6)
    {
      pop_close (server);
      strcpy (pop_error,
              "Username too long; recompile pop.c with larger ERROR_MAX");
      return (0);
    }
  sprintf (pop_error, "USER %s", username);

  if (sendline (server, pop_error) || getok (server))
    {
      return (0);
    }

  if (strlen (password) > ERROR_MAX - 6)
    {
      pop_close (server);
      strcpy (pop_error,
              "Password too long; recompile pop.c with larger ERROR_MAX");
      return (0);
    }
  sprintf (pop_error, "PASS %s", password);

  if (sendline (server, pop_error) || getok (server))
    {
      return (0);
    }

  return (server);
}

/*
 * Function: pop_stat
 *
 * Purpose: Issue the STAT command to the server and return (in the
 *      value parameters) the number of messages in the maildrop and
 *      the total size of the maildrop.
 *
 * Return value: 0 on success, or non-zero with an error in pop_error
 *      in failure.
 *
 * Side effects: On failure, may make further operations on the
 *      connection impossible.
 */
int
pop_stat (server, count, size)
     popserver server;
     int *count;
     int *size;
{
  char *fromserver;
  char *end_ptr;

  if (server->in_multi)
    {
      strcpy (pop_error, "In multi-line query in pop_stat");
      return (-1);
    }

  if (sendline (server, "STAT") || (pop_getline (server, &fromserver) < 0))
    return (-1);

  if (strncmp (fromserver, "+OK ", 4))
    {
      if (0 == strncmp (fromserver, "-ERR", 4))
        {
          strncpy (pop_error, fromserver, ERROR_MAX);
        }
      else
        {
          strcpy (pop_error,
                  "Unexpected response from POP server in pop_stat");
          pop_trash (server);
        }
      return (-1);
    }

  errno = 0;
  *count = strtol (&fromserver[4], &end_ptr, 10);
  /* Check validity of string-to-integer conversion. */
  if (fromserver + 4 == end_ptr || *end_ptr != ' ' || errno)
    {
      strcpy (pop_error, "Unexpected response from POP server in pop_stat");
      pop_trash (server);
      return (-1);
    }

  fromserver = end_ptr;

  errno = 0;
  *size = strtol (fromserver + 1, &end_ptr, 10);
  if (fromserver + 1 == end_ptr || errno)
    {
      strcpy (pop_error, "Unexpected response from POP server in pop_stat");
      pop_trash (server);
      return (-1);
    }

  return (0);
}

/*
 * Function: pop_list
 *
 * Purpose: Performs the POP "list" command and returns (in value
 *      parameters) two malloc'd zero-terminated arrays -- one of
 *      message IDs, and a parallel one of sizes.
 *
 * Arguments:
 *      server  The pop connection to talk to.
 *      message The number of the one message about which to get
 *              information, or 0 to get information about all
 *              messages.
 *
 * Return value: 0 on success, non-zero with error in pop_error on
 *      failure.
 *
 * Side effects: On failure, may make further operations on the
 *      connection impossible.
 */
int
pop_list (server, message, IDs, sizes)
     popserver server;
     int message;
     int **IDs;
     int **sizes;
{
  int how_many, i;
  char *fromserver;

  if (server->in_multi)
    {
      strcpy (pop_error, "In multi-line query in pop_list");
      return (-1);
    }

  if (message)
    how_many = 1;
  else
    {
      int count, size;
      if (pop_stat (server, &count, &size))
        return (-1);
      how_many = count;
    }

  *IDs = (int *) malloc ((how_many + 1) * sizeof (int));
  *sizes = (int *) malloc ((how_many + 1) * sizeof (int));
  if (! (*IDs && *sizes))
    {
      strcpy (pop_error, "Out of memory in pop_list");
      return (-1);
    }

  if (message)
    {
      sprintf (pop_error, "LIST %d", message);
      if (sendline (server, pop_error))
        {
          free ((char *) *IDs);
          free ((char *) *sizes);
          return (-1);
        }
      if (pop_getline (server, &fromserver) < 0)
        {
          free ((char *) *IDs);
          free ((char *) *sizes);
          return (-1);
        }
      if (strncmp (fromserver, "+OK ", 4))
        {
          if (! strncmp (fromserver, "-ERR", 4))
            strncpy (pop_error, fromserver, ERROR_MAX);
          else
            {
              strcpy (pop_error,
                      "Unexpected response from server in pop_list");
              pop_trash (server);
            }
          free ((char *) *IDs);
          free ((char *) *sizes);
          return (-1);
        }
      (*IDs)[0] = atoi (&fromserver[4]);
      fromserver = index (&fromserver[4], ' ');
      if (! fromserver)
        {
          strcpy (pop_error,
                  "Badly formatted response from server in pop_list");
          pop_trash (server);
          free ((char *) *IDs);
          free ((char *) *sizes);
          return (-1);
        }
      (*sizes)[0] = atoi (fromserver);
      (*IDs)[1] = (*sizes)[1] = 0;
      return (0);
    }
  else
    {
      if (pop_multi_first (server, "LIST", &fromserver))
        {
          free ((char *) *IDs);
          free ((char *) *sizes);
          return (-1);
        }
      for (i = 0; i < how_many; i++)
        {
          if (pop_multi_next (server, &fromserver) <= 0)
            {
              free ((char *) *IDs);
              free ((char *) *sizes);
              return (-1);
            }
          (*IDs)[i] = atoi (fromserver);
          fromserver = index (fromserver, ' ');
          if (! fromserver)
            {
              strcpy (pop_error,
                      "Badly formatted response from server in pop_list");
              free ((char *) *IDs);
              free ((char *) *sizes);
              pop_trash (server);
              return (-1);
            }
          (*sizes)[i] = atoi (fromserver);
        }
      if (pop_multi_next (server, &fromserver) < 0)
        {
          free ((char *) *IDs);
          free ((char *) *sizes);
          return (-1);
        }
      else if (fromserver)
        {
          strcpy (pop_error,
                  "Too many response lines from server in pop_list");
          free ((char *) *IDs);
          free ((char *) *sizes);
          return (-1);
        }
      (*IDs)[i] = (*sizes)[i] = 0;
      return (0);
    }
}

/*
 * Function: pop_retrieve
 *
 * Purpose: Retrieve a specified message from the maildrop.
 *
 * Arguments:
 *      server  The server to retrieve from.
 *      message The message number to retrieve.
 *      markfrom
 *              If true, then mark the string "From " at the beginning
 *              of lines with '>'.
 *      msg_buf Output parameter to which a buffer containing the
 *              message is assigned.
 *
 * Return value: The number of bytes in msg_buf, which may contain
 *      embedded nulls, not including its final null, or -1 on error
 *      with pop_error set.
 *
 * Side effects: May kill connection on error.
 */
int
pop_retrieve (server, message, markfrom, msg_buf)
     popserver server;
     int message;
     int markfrom;
     char **msg_buf;
{
  int *IDs, *sizes, bufsize, fromcount = 0, cp = 0;
  char *ptr, *fromserver;
  int ret;

  if (server->in_multi)
    {
      strcpy (pop_error, "In multi-line query in pop_retrieve");
      return (-1);
    }

  if (pop_list (server, message, &IDs, &sizes))
    return (-1);

  if (pop_retrieve_first (server, message, &fromserver))
    {
      return (-1);
    }

  /*
   * The "5" below is an arbitrary constant -- I assume that if
   * there are "From" lines in the text to be marked, there
   * probably won't be more than 5 of them.  If there are, I
   * allocate more space for them below.
   */
  bufsize = sizes[0] + (markfrom ? 5 : 0);
  ptr = (char *)malloc (bufsize);
  free ((char *) IDs);
  free ((char *) sizes);

  if (! ptr)
    {
      strcpy (pop_error, "Out of memory in pop_retrieve");
      pop_retrieve_flush (server);
      return (-1);
    }

  while ((ret = pop_retrieve_next (server, &fromserver)) >= 0)
    {
      if (! fromserver)
        {
          ptr[cp] = '\0';
          *msg_buf = ptr;
          return (cp);
        }
      if (markfrom && fromserver[0] == 'F' && fromserver[1] == 'r' &&
          fromserver[2] == 'o' && fromserver[3] == 'm' &&
          fromserver[4] == ' ')
        {
          if (++fromcount == 5)
            {
              bufsize += 5;
              ptr =