/*************************************************
*     Exim - an Internet mail transport agent    *
*************************************************/

/* Copyright (c) Tom Kistner <tom@duncanthrax.net> 2003-???? */
/* License: GPL */

/* Code for setting up a MBOX style spool file inside a /scan/<msgid>
sub directory of exim's spool directory. */

#include "exim.h"
#ifdef WITH_CONTENT_SCAN

/* externals, we must reset them on unspooling */
#ifdef WITH_OLD_DEMIME
extern int demime_ok;
extern struct file_extension *file_extensions;
#endif

extern int malware_ok;
extern int spam_ok;

int spool_mbox_ok = 0;
uschar spooled_message_id[17];

/* returns a pointer to the FILE, and puts the size in bytes into mbox_file_size
 * normally, source_file_override is NULL */

FILE *spool_mbox(unsigned long *mbox_file_size, uschar *source_file_override) {
  uschar message_subdir[2];
  uschar buffer[16384];
  uschar *temp_string;
  uschar *mbox_path;
  FILE *mbox_file = NULL;
  FILE *data_file = NULL;
  FILE *yield = NULL;
  header_line *my_headerlist;
  struct stat statbuf;
  int i, j;
  void *reset_point = store_get(0);

  mbox_path = string_sprintf("%s/scan/%s/%s.eml", spool_directory, message_id,
    message_id);

  /* Skip creation if already spooled out as mbox file */
  if (!spool_mbox_ok) {
    /* create temp directory inside scan dir, directory_make works recursively */
    temp_string = string_sprintf("scan/%s", message_id);
    if (!directory_make(spool_directory, temp_string, 0750, FALSE)) {
      log_write(0, LOG_MAIN|LOG_PANIC, "%s", string_open_failed(errno,
        "scan directory %s/scan/%s", spool_directory, temp_string));
      goto OUT;
    };

    /* open [message_id].eml file for writing */
    mbox_file = modefopen(mbox_path, "wb", SPOOL_MODE);
    if (mbox_file == NULL) {
      log_write(0, LOG_MAIN|LOG_PANIC, "%s", string_open_failed(errno,
        "scan file %s", mbox_path));
      goto OUT;
    };

    /* Generate mailbox headers. The $received_for variable is (up to at least
    Exim 4.64) never set here, because it is only set when expanding the
    contents of the Received: header line. However, the code below will use it
    if it should become available in future. */

    temp_string = expand_string(
      US"From ${if def:return_path{$return_path}{MAILER-DAEMON}} ${tod_bsdinbox}\n"
      "${if def:sender_address{X-Envelope-From: <${sender_address}>\n}}"
      "${if def:recipients{X-Envelope-To: ${recipients}\n}}");

    if (temp_string != NULL) {
      i = fwrite(temp_string, Ustrlen(temp_string), 1, mbox_file);
      if (i != 1) {
        log_write(0, LOG_MAIN|LOG_PANIC, "Error/short write while writing \
            mailbox headers to %s", mbox_path);
        goto OUT;
      };
    };

    /* write all header lines to mbox file */
    my_headerlist = header_list;
    for (my_headerlist = header_list; my_headerlist != NULL;
      my_headerlist = my_headerlist->next)
    {
      /* skip deleted headers */
      if (my_headerlist->type == '*') continue;

      i = fwrite(my_headerlist->text, my_headerlist->slen, 1, mbox_file);
      if (i != 1) {
        log_write(0, LOG_MAIN|LOG_PANIC, "Error/short write while writing \
            message headers to %s", mbox_path);
        goto OUT;
      };
    };

    /* End headers */
    if (fwrite("\n", 1, 1, mbox_file) != 1) {
      log_write(0, LOG_MAIN|LOG_PANIC, "Error/short write while writing \
        message headers to %s", mbox_path);
      goto OUT;
    }

    /* copy body file */
    if (source_file_override == NULL) {
      message_subdir[1] = '\0';
      for (i = 0; i < 2; i++) {
        message_subdir[0] = (split_spool_directory == (i == 0))? message_id[5] : 0;
        temp_string = string_sprintf("%s/input/%s/%s-D", spool_directory,
          message_subdir, message_id);
        data_file = Ufopen(temp_string, "rb");
        if (data_file != NULL) break;
      };
    } else {
      data_file = Ufopen(source_file_override, "rb");
    };

    if (data_file == NULL) {
      log_write(0, LOG_MAIN|LOG_PANIC, "Could not open datafile for message %s",
        message_id);
      goto OUT;
    };

    /* The code used to use this line, but it doesn't work in Cygwin.
     *
     *  (void)fread(data_buffer, 1, 18, data_file);
     *
     * What's happening is that spool_mbox used to use an fread to jump over the
     * file header. That fails under Cygwin because the header is locked, but
     * doing an fseek succeeds. We have to output the leading newline
     * explicitly, because the one in the file is parted of the locked area.
     */

    if (!source_file_override)
      (void)fseek(data_file, SPOOL_DATA_START_OFFSET, SEEK_SET);

    do {
      j = fread(buffer, 1, sizeof(buffer), data_file);

      if (j > 0) {
        i = fwrite(buffer, j, 1, mbox_file);
        if (i != 1) {
          log_write(0, LOG_MAIN|LOG_PANIC, "Error/short write while writing \
              message body to %s", mbox_path);
          goto OUT;
        };
      };
    } while (j > 0);

    (void)fclose(mbox_file);
    mbox_file = NULL;

    Ustrcpy(spooled_message_id, message_id);
    spool_mbox_ok = 1;
  };

  /* get the size of the mbox message and open [message_id].eml file for reading*/
  if (Ustat(mbox_path, &statbuf) != 0 ||
      (yield = Ufopen(mbox_path,"rb")) == NULL) {
    log_write(0, LOG_MAIN|LOG_PANIC, "%s", string_open_failed(errno,
      "scan file %s", mbox_path));
    goto OUT;
  };

  *mbox_file_size = statbuf.st_size;

  OUT:
  if (data_file) (void)fclose(data_file);
  if (mbox_file) (void)fclose(mbox_file);
  store_reset(reset_point);
  return yield;
}

/* remove mbox spool file, demimed files and temp directory */
void unspool_mbox(void) {

  /* reset all exiscan state variables */
  #ifdef WITH_OLD_DEMIME
  demime_ok = 0;
  demime_errorlevel = 0;
  demime_reason = NULL;
  file_extensions = NULL;
  #endif

  spam_ok = 0;
  malware_ok = 0;

  if (spool_mbox_ok && !no_mbox_unspool) {
    uschar *mbox_path;
    uschar *file_path;
    int n;
    struct dirent *entry;
    DIR *tempdir;

    mbox_path = string_sprintf("%s/scan/%s", spool_directory, spooled_message_id);

    tempdir = opendir(CS mbox_path);
    if (!tempdir) {
      debug_printf("Unable to opendir(%s): %s\n", mbox_path, strerror(errno));
      /* Just in case we still can: */
      rmdir(CS mbox_path);
      return;
    }
    /* loop thru dir & delete entries */
    while((entry = readdir(tempdir)) != NULL) {
      uschar *name = US entry->d_name;
      if (Ustrcmp(name, US".") == 0 || Ustrcmp(name, US"..") == 0) continue;

      file_path = string_sprintf("%s/%s", mbox_path, name);
      debug_printf("unspool_mbox(): unlinking '%s'\n", file_path);
      n = unlink(CS file_path);
    };

    closedir(tempdir);

    /* remove directory */
    rmdir(CS mbox_path);
    store_reset(mbox_path);
  };
  spool_mbox_ok = 0;
}

#endif
