/* Copyright (c) 2002-2018 Pigeonhole authors, see the included COPYING file

 */

#include "lib.h"

#include "istream.h"

#include "istream-seekable.h"

#include "str.h"

#include "str-sanitize.h"

#include "strescape.h"

#include "safe-mkstemp.h"

#include "path-util.h"

#include "message-address.h"

#include "mbox-from.h"

#include "raw-storage.h"

#include "mail-storage-service.h"

#include "mail-namespace.h"

#include "master-service.h"

#include "master-service-settings.h"

#include "settings-parser.h"

#include "mail-raw.h"

#include <stdio.h>

#include <unistd.h>

#include <fcntl.h>

#include <pwd.h>

/*

 * Configuration

 */

#define DEFAULT_ENVELOPE_SENDER "MAILER-DAEMON"

/* After buffer grows larger than this, create a temporary file to /tmp

   where to read the mail. */

#define MAIL_MAX_MEMORY_BUFFER (1024*128)

static const char *wanted_headers[] = {

  "From", "Message-ID", "Subject", "Return-Path",

  NULL

};

/*

 * Global data

 */

struct mail_raw_user {

  struct mail_namespace *ns;

  struct mail_user *mail_user;

};

/*

 * Raw mail implementation

 */

static int seekable_fd_callback(const char **path_r, void *context)

{

  struct mail_user *ruser = (struct mail_user *)context;

  string_t *path;

  int fd;

  path = t_str_new(128);

  mail_user_set_get_temp_prefix(path, ruser->set);

  fd = safe_mkstemp(path, 0600, (uid_t)-1, (gid_t)-1);

  if (fd == -1) {

    i_error("safe_mkstemp(%s) failed: %m", str_c(path));

    return -1;

  }

  /* we just want the fd, unlink it */

  if (i_unlink(str_c(path)) < 0) {

    /* shouldn't happen.. */

    i_close_fd(&fd);

    return -1;

  }

  *path_r = str_c(path);

  return fd;

}

static struct istream *

mail_raw_create_stream(struct mail_user *ruser, int fd, time_t *mtime_r,

           const char **sender)

{

  struct istream *input, *input2, *input_list[2];

  const unsigned char *data;

  size_t i, size;

  int ret, tz;

  char *env_sender = NULL;

  *mtime_r = (time_t)-1;

  fd_set_nonblock(fd, FALSE);

  input = i_stream_create_fd(fd, 4096);

  input->blocking = TRUE;

  /* If input begins with a From-line, drop it */

  ret = i_stream_read_bytes(input, &data, &size, 5);

  if (ret > 0 && memcmp(data, "From ", 5) == 0) {

    /* Skip until the first LF */

    i_stream_skip(input, 5);

    while (i_stream_read_more(input, &data, &size) > 0) {

      for (i = 0; i < size; i++) {

        if (data[i] == '\n')

          break;

      }

      if (i != size) {

        (void)mbox_from_parse(data, i, mtime_r,

                  &tz, &env_sender);

        i_stream_skip(input, i + 1);

        break;

      }

      i_stream_skip(input, size);

    }

  }

  if (env_sender != NULL && sender != NULL)

    *sender = t_strdup(env_sender);

  i_free(env_sender);

  if (input->v_offset == 0) {

    input2 = input;

    i_stream_ref(input2);

  } else {

    input2 = i_stream_create_limit(input, (uoff_t)-1);

  }

  i_stream_unref(&input);

  input_list[0] = input2; input_list[1] = NULL;

  input = i_stream_create_seekable(input_list, MAIL_MAX_MEMORY_BUFFER,

           seekable_fd_callback, ruser);

  i_stream_unref(&input2);

  return input;

}

/*

 * Init/Deinit

 */

struct mail_user *mail_raw_user_create(struct mail_user *mail_user)

{

  struct mail_storage_service_ctx *storage_service =

    mail_storage_service_user_get_service_ctx(

      mail_user->service_user);

  struct settings_instance *set_instance =

    mail_storage_service_user_get_settings_instance(mail_user->service_user);

  return raw_storage_create_from_set(storage_service, set_instance);

}

/*

 * Open raw mail data

 */

static struct mail_raw *

mail_raw_create(struct mail_user *ruser, struct istream *input,

    const char *mailfile, const char *sender, time_t mtime)

{

  struct mail_raw *mailr;

  struct mailbox_header_lookup_ctx *headers_ctx;

  const char *envelope_sender, *error;

  int ret;

  if (mailfile != NULL && *mailfile != '/') {

    if (t_abspath(mailfile, &mailfile, &error) < 0)

      i_fatal("t_abspath(%s) failed: %s", mailfile, error);

  }

  mailr = i_new(struct mail_raw, 1);

  envelope_sender = sender != NULL ? sender : DEFAULT_ENVELOPE_SENDER;

  if (mailfile == NULL) {

    ret = raw_mailbox_alloc_stream(ruser, input, mtime,

                 envelope_sender, &mailr->box);

  } else {

    ret = raw_mailbox_alloc_path(ruser, mailfile, (time_t)-1,

               envelope_sender, &mailr->box);

  }

  if (ret < 0) {

    if (mailfile == NULL) {

      i_fatal("Can't open delivery mail as raw: %s",

        mailbox_get_last_internal_error(

          mailr->box, NULL));

    } else {

      i_fatal("Can't open delivery mail as raw (file=%s): %s",

        mailfile,

        mailbox_get_last_internal_error(

          mailr->box, NULL));

    }

  }

  mailr->trans = mailbox_transaction_begin(mailr->box, 0, __func__);

  headers_ctx = mailbox_header_lookup_init(mailr->box, wanted_headers);

  mailr->mail = mail_alloc(mailr->trans, 0, headers_ctx);

  mailbox_header_lookup_unref(&headers_ctx);

  mail_set_seq(mailr->mail, 1);

  return mailr;

}

struct mail_raw *

mail_raw_open_stream(struct mail_user *ruser, struct istream *input)

{

  struct mail_raw *mailr;

  i_assert(input->seekable);

  i_stream_set_name(input, "data");

  mailr = mail_raw_create(ruser, input, NULL, NULL, (time_t)-1);

  return mailr;

}

struct mail_raw *

mail_raw_open_data(struct mail_user *ruser, string_t *mail_data)

{

  struct mail_raw *mailr;

  struct istream *input;

  input = i_stream_create_copy_from_data(str_data(mail_data),

                 str_len(mail_data));

  mailr = mail_raw_open_stream(ruser, input);

  i_stream_unref(&input);

  return mailr;

}

struct mail_raw *mail_raw_open_file(struct mail_user *ruser, const char *path)

{

  struct mail_raw *mailr;

  struct istream *input = NULL;

  time_t mtime = (time_t)-1;

  const char *sender = NULL;

  if (path == NULL || strcmp(path, "-") == 0) {

    path = NULL;

    input = mail_raw_create_stream(ruser, 0, &mtime, &sender);

  }

  mailr = mail_raw_create(ruser, input, path, sender, mtime);

  i_stream_unref(&input);

  return mailr;

}

void mail_raw_close(struct mail_raw **mailr)

{

  mail_free(&(*mailr)->mail);

  mailbox_transaction_rollback(&(*mailr)->trans);

  mailbox_free(&(*mailr)->box);

  i_free(*mailr);

  *mailr = NULL;

}