// Copyright (c) 2009 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "pam_client.h"
#include "base/logging.h"

namespace chromeos {

const char PamClient::kDisplayName[] = ":0.0";
const char PamClient::kLocalUser[] = "root";
const char PamClient::kLocalHost[] = "localhost";

int PamClient::PamConversationCallback(int num_msg,
                                       const struct pam_message** msg,
                                       struct pam_response** resp,
                                       void* credentials) {
  *resp = new struct pam_response[num_msg];
  PamClient::UserCredentials* user_credentials =
    static_cast<PamClient::UserCredentials*>(credentials);
  for (int i = 0; i < num_msg; i++) {
    resp[i]->resp = 0;
    resp[i]->resp_retcode = 0;
    switch (msg[i]->msg_style) {
      case PAM_PROMPT_ECHO_ON:
        resp[i]->resp = strdup(user_credentials->username.c_str());
        break;
      case PAM_PROMPT_ECHO_OFF:
        resp[i]->resp = strdup(user_credentials->password.c_str());
        break;
    }
  }
  return PAM_SUCCESS;
}

void PamClient::Init(const std::string& service_name) {
  last_pam_result_ = pam_start(service_name.c_str(), NULL,
                               &pam_conversation_callback_, &pam_handle_);
  if (last_pam_result_)
    LOG(ERROR) << "didn't start pam: "
               << pam_strerror(pam_handle_, last_pam_result_);

  // Set startup items
  last_pam_result_ = pam_set_item(pam_handle_, PAM_TTY, kDisplayName);
  last_pam_result_ = pam_set_item(pam_handle_, PAM_RHOST, kLocalHost);
  last_pam_result_ = pam_set_item(pam_handle_, PAM_RUSER, kLocalUser);
}

PamClient::PamClient()
    : pam_handle_(NULL), last_pam_result_(PAM_SUCCESS) {
  // Initialize pam with our service name, no default user name,
  // pam conversation handle and finally our pam handle
  pam_conversation_callback_.conv = PamConversationCallback;
  pam_conversation_callback_.appdata_ptr =
    static_cast<void*>(&user_credentials_);
}

PamClient::~PamClient() {
  last_pam_result_ = pam_end(pam_handle_, last_pam_result_);
}

bool PamClient::Authenticate(const std::string& username,
                             const std::string& password) {
  user_credentials_.username.assign(username);
  user_credentials_.password.assign(password);
  // TODO(sosa) - add better logging data by adding different cases
  last_pam_result_ = pam_authenticate(pam_handle_, 0);
  return last_pam_result_ == PAM_SUCCESS;
}

bool PamClient::StartSession() {
  // TODO(sosa) - add better logging data by adding different cases
  last_pam_result_ = pam_setcred(pam_handle_, PAM_ESTABLISH_CRED);
  if (last_pam_result_ == PAM_SUCCESS) {
    last_pam_result_ = pam_open_session(pam_handle_, 0);
  }
  return last_pam_result_ == PAM_SUCCESS;
}

bool PamClient::CloseSession() {
  // TODO(sosa) - add better logging data by adding different cases
  last_pam_result_ = pam_close_session(pam_handle_, 0);
  if (last_pam_result_)
    LOG(WARNING) << "didn't close session: "
                 << pam_strerror(pam_handle_, last_pam_result_);
  // Do this regardless of last result
  last_pam_result_ = pam_setcred(pam_handle_, PAM_DELETE_CRED);
  return last_pam_result_ == PAM_SUCCESS;
}

}  // namespace chromeos