New version 1.2.3.

[misc] / qmail-checkspam.c

/* -*-c-*-
 *
 * $Id: qmail-checkspam.c,v 1.2 2004/04/08 01:36:26 mdw Exp $
 *
 * Filter messages for spam
 *
 * (c) 2003 Mark Wooding
 */

/*----- Licensing notice --------------------------------------------------*
 *
 * 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

/*----- Header files ------------------------------------------------------*/

#include <ctype.h>
#include <errno.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <sys/types.h>
#include <sys/unistd.h>

#include <libspamc.h>

/*----- Main code ---------------------------------------------------------*/

static const char *strenv(const char *e, const char *d)
{
  const char *p = getenv(e);
  if (!p) return (d);
  return (p);
}

static double dblenv(const char *e, double d)
{
  const char *p = getenv(e);
  char *q;
  int err = errno;
  double f;
  if (!p) return (d);
  errno = 0;
  f = strtod(p, &q);
  if (errno) return (d);
  errno = err;
  return (f);
}

static int intenv(const char *e, int d)
{
  const char *p = getenv(e);
  char *q;
  int err = errno;
  long l;
  if (!p) return (d);
  errno = 0;
  l = strtol(p, &q, 0);
  if (errno) return (d);
  errno = err;
  if (l < 0 || l > INT_MAX) return (d);
  return ((int)l);
}

int shovel(int from, int to)
{
  char buf[4096];
  ssize_t n;
  char *p;
  size_t r;

  for (;;) {
    n = read(from, buf, sizeof(buf));
    if (n < 0 && errno != EINTR && errno != EAGAIN)
      return (-1);
    else if (!n)
      return (0);
    p = buf;
    r = n;
    while (r) {
      n = write(to, p, n);
      if (n <= 0 && errno != EINTR && errno != EAGAIN)
	return (-1);
      r -= n;
      p += n;
    }
  }
}

int main(int argc, char *argv[])
{
  struct sockaddr sa;
  struct message m;
  int fd_m[2], fd_e[2];
  pid_t kid;
  const char *qmq;
  int rc;

  m.max_len = intenv("QMAIL_CHECKSPAM_MAXLEN", 2 * 1024 * 1024);
  m.timeout = intenv("QMAIL_CHECKSPAM_TIMEOUT", 300);
  rc = message_read(0, 0, &m);
  if (rc != 0 && rc != EX_TOOBIG)
    return (54);
  if (!rc) {
    if (lookup_host(strenv("QMAIL_CHECKSPAM_SPAMDHOST", "localhost"),
		    intenv("QMAIL_CHECKSPAM_SPAMDPORT", 783),
		    &sa))
      return (56);
    if (message_filter(&sa, "spamd", 0, &m))
      return (74);
    if (m.score >= dblenv("QMAIL_CHECKSPAM_THRESH", m.threshold))
      return (31);
  }
  if (pipe(fd_m) || pipe(fd_e))
    return (56);
  if ((kid = fork()) < 0)
    return (56);
  if (!kid) {
    close(fd_m[0]);
    close(fd_e[0]);
    if (message_write(fd_m[1], &m) < 0)
      _exit(127);
    if (rc == EX_TOOBIG && shovel(0, fd_m[1]))
      _exit(127);
    close(fd_m[1]);
    if (shovel(1, fd_e[1]))
      _exit(127);
    close(fd_e[1]);
    _exit(0);
  }

  dup2(fd_m[0], 0);
  dup2(fd_e[0], 1);
  close(fd_m[0]);
  close(fd_e[0]);
  close(fd_m[1]);
  close(fd_e[1]);
  qmq = strenv("QMAIL_CHECKSPAM_QUEUE", "/var/qmail/bin/qmail-queue");
  execlp(qmq, qmq, (char *)0);
  fprintf(stderr, "failed to exec: %s\n", strerror(errno));
  return (56);
}

/*----- That's all, folks -------------------------------------------------*/