/*
 * nghttp2 - HTTP/2 C Library
 *
 * Copyright (c) 2012 Tatsuhiro Tsujikawa
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
#include "shrpx_config.h"

#include <pwd.h>
#include <netdb.h>
#include <syslog.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>

#include <cstring>
#include <cerrno>
#include <limits>
#include <fstream>

#include <nghttp2/nghttp2.h>

#include "http-parser/http_parser.h"

#include "shrpx_log.h"
#include "shrpx_ssl.h"
#include "shrpx_http.h"
#include "http2.h"
#include "util.h"

using namespace nghttp2;

namespace shrpx {

const char SHRPX_OPT_PRIVATE_KEY_FILE[] = "private-key-file";
const char SHRPX_OPT_PRIVATE_KEY_PASSWD_FILE[] = "private-key-passwd-file";
const char SHRPX_OPT_CERTIFICATE_FILE[] = "certificate-file";
const char SHRPX_OPT_DH_PARAM_FILE[] = "dh-param-file";
const char SHRPX_OPT_SUBCERT[] = "subcert";

const char SHRPX_OPT_BACKEND[] = "backend";
const char SHRPX_OPT_FRONTEND[] = "frontend";
const char SHRPX_OPT_WORKERS[] = "workers";
const char SHRPX_OPT_HTTP2_MAX_CONCURRENT_STREAMS[] =
    "http2-max-concurrent-streams";
const char SHRPX_OPT_LOG_LEVEL[] = "log-level";
const char SHRPX_OPT_DAEMON[] = "daemon";
const char SHRPX_OPT_HTTP2_PROXY[] = "http2-proxy";
const char SHRPX_OPT_HTTP2_BRIDGE[] = "http2-bridge";
const char SHRPX_OPT_CLIENT_PROXY[] = "client-proxy";
const char SHRPX_OPT_ADD_X_FORWARDED_FOR[] = "add-x-forwarded-for";
const char SHRPX_OPT_STRIP_INCOMING_X_FORWARDED_FOR[] =
    "strip-incoming-x-forwarded-for";
const char SHRPX_OPT_NO_VIA[] = "no-via";
const char SHRPX_OPT_FRONTEND_HTTP2_READ_TIMEOUT[] =
    "frontend-http2-read-timeout";
const char SHRPX_OPT_FRONTEND_READ_TIMEOUT[] = "frontend-read-timeout";
const char SHRPX_OPT_FRONTEND_WRITE_TIMEOUT[] = "frontend-write-timeout";
const char SHRPX_OPT_BACKEND_READ_TIMEOUT[] = "backend-read-timeout";
const char SHRPX_OPT_BACKEND_WRITE_TIMEOUT[] = "backend-write-timeout";
const char SHRPX_OPT_STREAM_READ_TIMEOUT[] = "stream-read-timeout";
const char SHRPX_OPT_STREAM_WRITE_TIMEOUT[] = "stream-write-timeout";
const char SHRPX_OPT_ACCESSLOG_FILE[] = "accesslog-file";
const char SHRPX_OPT_ACCESSLOG_SYSLOG[] = "accesslog-syslog";
const char SHRPX_OPT_ACCESSLOG_FORMAT[] = "accesslog-format";
const char SHRPX_OPT_ERRORLOG_FILE[] = "errorlog-file";
const char SHRPX_OPT_ERRORLOG_SYSLOG[] = "errorlog-syslog";
const char SHRPX_OPT_BACKEND_KEEP_ALIVE_TIMEOUT[] =
    "backend-keep-alive-timeout";
const char SHRPX_OPT_FRONTEND_HTTP2_WINDOW_BITS[] =
    "frontend-http2-window-bits";
const char SHRPX_OPT_BACKEND_HTTP2_WINDOW_BITS[] = "backend-http2-window-bits";
const char SHRPX_OPT_FRONTEND_HTTP2_CONNECTION_WINDOW_BITS[] =
    "frontend-http2-connection-window-bits";
const char SHRPX_OPT_BACKEND_HTTP2_CONNECTION_WINDOW_BITS[] =
    "backend-http2-connection-window-bits";
const char SHRPX_OPT_FRONTEND_NO_TLS[] = "frontend-no-tls";
const char SHRPX_OPT_BACKEND_NO_TLS[] = "backend-no-tls";
const char SHRPX_OPT_BACKEND_TLS_SNI_FIELD[] = "backend-tls-sni-field";
const char SHRPX_OPT_PID_FILE[] = "pid-file";
const char SHRPX_OPT_USER[] = "user";
const char SHRPX_OPT_SYSLOG_FACILITY[] = "syslog-facility";
const char SHRPX_OPT_BACKLOG[] = "backlog";
const char SHRPX_OPT_CIPHERS[] = "ciphers";
const char SHRPX_OPT_CLIENT[] = "client";
const char SHRPX_OPT_INSECURE[] = "insecure";
const char SHRPX_OPT_CACERT[] = "cacert";
const char SHRPX_OPT_BACKEND_IPV4[] = "backend-ipv4";
const char SHRPX_OPT_BACKEND_IPV6[] = "backend-ipv6";
const char SHRPX_OPT_BACKEND_HTTP_PROXY_URI[] = "backend-http-proxy-uri";
const char SHRPX_OPT_READ_RATE[] = "read-rate";
const char SHRPX_OPT_READ_BURST[] = "read-burst";
const char SHRPX_OPT_WRITE_RATE[] = "write-rate";
const char SHRPX_OPT_WRITE_BURST[] = "write-burst";
const char SHRPX_OPT_WORKER_READ_RATE[] = "worker-read-rate";
const char SHRPX_OPT_WORKER_READ_BURST[] = "worker-read-burst";
const char SHRPX_OPT_WORKER_WRITE_RATE[] = "worker-write-rate";
const char SHRPX_OPT_WORKER_WRITE_BURST[] = "worker-write-burst";
const char SHRPX_OPT_NPN_LIST[] = "npn-list";
const char SHRPX_OPT_TLS_PROTO_LIST[] = "tls-proto-list";
const char SHRPX_OPT_VERIFY_CLIENT[] = "verify-client";
const char SHRPX_OPT_VERIFY_CLIENT_CACERT[] = "verify-client-cacert";
const char SHRPX_OPT_CLIENT_PRIVATE_KEY_FILE[] = "client-private-key-file";
const char SHRPX_OPT_CLIENT_CERT_FILE[] = "client-cert-file";
const char SHRPX_OPT_FRONTEND_HTTP2_DUMP_REQUEST_HEADER[] =
    "frontend-http2-dump-request-header";
const char SHRPX_OPT_FRONTEND_HTTP2_DUMP_RESPONSE_HEADER[] =
    "frontend-http2-dump-response-header";
const char SHRPX_OPT_HTTP2_NO_COOKIE_CRUMBLING[] = "http2-no-cookie-crumbling";
const char SHRPX_OPT_FRONTEND_FRAME_DEBUG[] = "frontend-frame-debug";
const char SHRPX_OPT_PADDING[] = "padding";
const char SHRPX_OPT_ALTSVC[] = "altsvc";
const char SHRPX_OPT_ADD_RESPONSE_HEADER[] = "add-response-header";
const char SHRPX_OPT_WORKER_FRONTEND_CONNECTIONS[] =
    "worker-frontend-connections";
const char SHRPX_OPT_NO_LOCATION_REWRITE[] = "no-location-rewrite";
const char SHRPX_OPT_BACKEND_HTTP1_CONNECTIONS_PER_HOST[] =
    "backend-http1-connections-per-host";
const char SHRPX_OPT_BACKEND_HTTP1_CONNECTIONS_PER_FRONTEND[] =
    "backend-http1-connections-per-frontend";
const char SHRPX_OPT_LISTENER_DISABLE_TIMEOUT[] = "listener-disable-timeout";
const char SHRPX_OPT_TLS_TICKET_KEY_FILE[] = "tls-ticket-key-file";
const char SHRPX_OPT_RLIMIT_NOFILE[] = "rlimit-nofile";
const char SHRPX_OPT_TLS_CTX_PER_WORKER[] = "tls-ctx-per-worker";
const char SHRPX_OPT_BACKEND_REQUEST_BUFFER[] = "backend-request-buffer";
const char SHRPX_OPT_BACKEND_RESPONSE_BUFFER[] = "backend-response-buffer";

namespace {
Config *config = nullptr;
} // namespace

const Config *get_config() { return config; }

Config *mod_config() { return config; }

void create_config() { config = new Config(); }

TicketKeys::~TicketKeys() {
  /* Erase keys from memory */
  for (auto &key : keys) {
    memset(&key, 0, sizeof(key));
  }
}

namespace {
int split_host_port(char *host, size_t hostlen, uint16_t *port_ptr,
                    const char *hostport) {
  // host and port in |hostport| is separated by single ','.
  const char *p = strchr(hostport, ',');
  if (!p) {
    LOG(ERROR) << "Invalid host, port: " << hostport;
    return -1;
  }
  size_t len = p - hostport;
  if (hostlen < len + 1) {
    LOG(ERROR) << "Hostname too long: " << hostport;
    return -1;
  }
  memcpy(host, hostport, len);
  host[len] = '\0';

  errno = 0;
  unsigned long d = strtoul(p + 1, nullptr, 10);
  if (errno == 0 && 1 <= d && d <= std::numeric_limits<uint16_t>::max()) {
    *port_ptr = d;
    return 0;
  } else {
    LOG(ERROR) << "Port is invalid: " << p + 1;
    return -1;
  }
}
} // namespace

namespace {
bool is_secure(const char *filename) {
  struct stat buf;
  int rv = stat(filename, &buf);
  if (rv == 0) {
    if ((buf.st_mode & S_IRWXU) && !(buf.st_mode & S_IRWXG) &&
        !(buf.st_mode & S_IRWXO)) {
      return true;
    }
  }

  return false;
}
} // namespace

std::unique_ptr<TicketKeys>
read_tls_ticket_key_file(const std::vector<std::string> &files) {
  auto ticket_keys = util::make_unique<TicketKeys>();
  auto &keys = ticket_keys->keys;
  keys.resize(files.size());
  size_t i = 0;
  for (auto &file : files) {
    std::ifstream f(file.c_str());
    if (!f) {
      LOG(ERROR) << "tls-ticket-key-file: could not open file " << file;
      return nullptr;
    }
    char buf[48];
    f.read(buf, sizeof(buf));
    if (f.gcount() != sizeof(buf)) {
      LOG(ERROR) << "tls-ticket-key-file: want to read 48 bytes but read "
                 << f.gcount() << " bytes from " << file;
      return nullptr;
    }

    auto &key = keys[i++];
    auto p = buf;
    memcpy(key.name, p, sizeof(key.name));
    p += sizeof(key.name);
    memcpy(key.aes_key, p, sizeof(key.aes_key));
    p += sizeof(key.aes_key);
    memcpy(key.hmac_key, p, sizeof(key.hmac_key));

    if (LOG_ENABLED(INFO)) {
      LOG(INFO) << "session ticket key: " << util::format_hex(key.name,
                                                              sizeof(key.name));
    }
  }
  return ticket_keys;
}

FILE *open_file_for_write(const char *filename) {
#if defined O_CLOEXEC
  auto fd = open(filename, O_WRONLY | O_CLOEXEC | O_CREAT | O_TRUNC,
                 S_IRUSR | S_IWUSR);
#else
  auto fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, S_IRUSR | S_IWUSR);

  // We get race condition if execve is called at the same time.
  if (fd != -1) {
    util::make_socket_closeonexec(fd);
  }
#endif
  if (fd == -1) {
    LOG(ERROR) << "Failed to open " << filename
               << " for writing. Cause: " << strerror(errno);
    return nullptr;
  }
  auto f = fdopen(fd, "wb");
  if (f == nullptr) {
    LOG(ERROR) << "Failed to open " << filename
               << " for writing. Cause: " << strerror(errno);
    return nullptr;
  }

  return f;
}

std::string read_passwd_from_file(const char *filename) {
  std::string line;

  if (!is_secure(filename)) {
    LOG(ERROR) << "Private key passwd file " << filename
               << " has insecure mode.";
    return line;
  }

  std::ifstream in(filename, std::ios::binary);
  if (!in) {
    LOG(ERROR) << "Could not open key passwd file " << filename;
    return line;
  }

  std::getline(in, line);
  return line;
}

std::unique_ptr<char[]> strcopy(const char *val) {
  return strcopy(val, strlen(val));
}

std::unique_ptr<char[]> strcopy(const char *val, size_t len) {
  auto res = util::make_unique<char[]>(len + 1);
  memcpy(res.get(), val, len);
  res[len] = '\0';
  return res;
}

std::unique_ptr<char[]> strcopy(const std::string &val) {
  return strcopy(val.c_str(), val.size());
}

std::vector<char *> parse_config_str_list(const char *s) {
  size_t len = 1;
  for (const char *first = s, *p = nullptr; (p = strchr(first, ','));
       ++len, first = p + 1)
    ;
  auto list = std::vector<char *>(len);
  auto first = strdup(s);
  len = 0;
  for (;;) {
    auto p = strchr(first, ',');
    if (p == nullptr) {
      break;
    }
    list[len++] = first;
    *p = '\0';
    first = p + 1;
  }
  list[len++] = first;

  return list;
}

void clear_config_str_list(std::vector<char *> &list) {
  if (list.empty()) {
    return;
  }

  free(list[0]);
  list.clear();
}

std::pair<std::string, std::string> parse_header(const char *optarg) {
  // We skip possible ":" at the start of optarg.
  const auto *colon = strchr(optarg + 1, ':');

  // name = ":" is not allowed
  if (colon == nullptr || (optarg[0] == ':' && colon == optarg + 1)) {
    return {"", ""};
  }

  auto value = colon + 1;
  for (; *value == '\t' || *value == ' '; ++value)
    ;

  return {std::string(optarg, colon), std::string(value, strlen(value))};
}

template <typename T>
int parse_uint(T *dest, const char *opt, const char *optarg) {
  char *end = nullptr;

  errno = 0;

  auto val = strtol(optarg, &end, 10);

  if (!optarg[0] || errno != 0 || *end || val < 0) {
    LOG(ERROR) << opt << ": bad value.  Specify an integer >= 0.";
    return -1;
  }

  *dest = val;

  return 0;
}

namespace {
template <typename T>
int parse_uint_with_unit(T *dest, const char *opt, const char *optarg) {
  auto n = util::parse_uint_with_unit(optarg);
  if (n == -1) {
    LOG(ERROR) << opt << ": bad value: '" << optarg << "'";
    return -1;
  }

  *dest = n;

  return 0;
}
} // namespace

template <typename T>
int parse_int(T *dest, const char *opt, const char *optarg) {
  char *end = nullptr;

  errno = 0;

  auto val = strtol(optarg, &end, 10);

  if (!optarg[0] || errno != 0 || *end) {
    LOG(ERROR) << opt << ": bad value.  Specify an integer.";
    return -1;
  }

  *dest = val;

  return 0;
}

namespace {
LogFragment make_log_fragment(LogFragmentType type,
                              std::unique_ptr<char[]> value = nullptr) {
  return LogFragment{type, std::move(value)};
}
} // namespace

namespace {
bool var_token(char c) {
  return util::isAlpha(c) || util::isDigit(c) || c == '_';
}
} // namespace

std::vector<LogFragment> parse_log_format(const char *optarg) {
  auto literal_start = optarg;
  auto p = optarg;
  auto eop = p + strlen(optarg);

  auto res = std::vector<LogFragment>();

  for (; p != eop;) {
    if (*p != '$') {
      ++p;
      continue;
    }

    auto var_start = p;

    ++p;

    for (; p != eop && var_token(*p); ++p)
      ;

    auto varlen = p - var_start;

    auto type = SHRPX_LOGF_NONE;
    const char *value = nullptr;
    size_t valuelen = 0;

    if (util::strieq("$remote_addr", var_start, varlen)) {
      type = SHRPX_LOGF_REMOTE_ADDR;
    } else if (util::strieq("$time_local", var_start, varlen)) {
      type = SHRPX_LOGF_TIME_LOCAL;
    } else if (util::strieq("$time_iso8601", var_start, varlen)) {
      type = SHRPX_LOGF_TIME_ISO8601;
    } else if (util::strieq("$request", var_start, varlen)) {
      type = SHRPX_LOGF_REQUEST;
    } else if (util::strieq("$status", var_start, varlen)) {
      type = SHRPX_LOGF_STATUS;
    } else if (util::strieq("$body_bytes_sent", var_start, varlen)) {
      type = SHRPX_LOGF_BODY_BYTES_SENT;
    } else if (util::istartsWith(var_start, varlen, "$http_")) {
      type = SHRPX_LOGF_HTTP;
      value = var_start + sizeof("$http_") - 1;
      valuelen = varlen - (sizeof("$http_") - 1);
    } else if (util::strieq("$remote_port", var_start, varlen)) {
      type = SHRPX_LOGF_REMOTE_PORT;
    } else if (util::strieq("$server_port", var_start, varlen)) {
      type = SHRPX_LOGF_SERVER_PORT;
    } else if (util::strieq("$request_time", var_start, varlen)) {
      type = SHRPX_LOGF_REQUEST_TIME;
    } else if (util::strieq("$pid", var_start, varlen)) {
      type = SHRPX_LOGF_PID;
    } else if (util::strieq("$alpn", var_start, varlen)) {
      type = SHRPX_LOGF_ALPN;
    } else {
      LOG(WARN) << "Unrecognized log format variable: "
                << std::string(var_start, varlen);
      continue;
    }

    if (literal_start < var_start) {
      res.push_back(
          make_log_fragment(SHRPX_LOGF_LITERAL,
                            strcopy(literal_start, var_start - literal_start)));
    }

    if (value == nullptr) {
      res.push_back(make_log_fragment(type));
    } else {
      res.push_back(make_log_fragment(type, strcopy(value, valuelen)));
      auto &v = res.back().value;
      for (size_t i = 0; v[i]; ++i) {
        if (v[i] == '_') {
          v[i] = '-';
        }
      }
    }

    literal_start = var_start + varlen;
  }

  if (literal_start != eop) {
    res.push_back(make_log_fragment(
        SHRPX_LOGF_LITERAL, strcopy(literal_start, eop - literal_start)));
  }

  return res;
}

namespace {
int parse_timeval(ev_tstamp *dest, const char *opt, const char *optarg) {
  time_t sec;

  if (parse_uint(&sec, opt, optarg) != 0) {
    return -1;
  }

  *dest = sec;

  return 0;
}
} // namespace

int parse_config(const char *opt, const char *optarg) {
  char host[NI_MAXHOST];
  uint16_t port;
  if (util::strieq(opt, SHRPX_OPT_BACKEND)) {
    if (split_host_port(host, sizeof(host), &port, optarg) == -1) {
      return -1;
    }

    DownstreamAddr addr;
    addr.host = strcopy(host);
    addr.port = port;

    mod_config()->downstream_addrs.push_back(std::move(addr));

    return 0;
  }

  if (util::strieq(opt, SHRPX_OPT_FRONTEND)) {
    if (split_host_port(host, sizeof(host), &port, optarg) == -1) {
      return -1;
    }

    mod_config()->host = strcopy(host);
    mod_config()->port = port;

    return 0;
  }

  if (util::strieq(opt, SHRPX_OPT_WORKERS)) {
    return parse_uint(&mod_config()->num_worker, opt, optarg);
  }

  if (util::strieq(opt, SHRPX_OPT_HTTP2_MAX_CONCURRENT_STREAMS)) {
    return parse_uint(&mod_config()->http2_max_concurrent_streams, opt, optarg);
  }

  if (util::strieq(opt, SHRPX_OPT_LOG_LEVEL)) {
    if (Log::set_severity_level_by_name(optarg) == -1) {
      LOG(ERROR) << opt << ": Invalid severity level: " << optarg;
      return -1;
    }

    return 0;
  }

  if (util::strieq(opt, SHRPX_OPT_DAEMON)) {
    mod_config()->daemon = util::strieq(optarg, "yes");

    return 0;
  }

  if (util::strieq(opt, SHRPX_OPT_HTTP2_PROXY)) {
    mod_config()->http2_proxy = util::strieq(optarg, "yes");

    return 0;
  }

  if (util::strieq(opt, SHRPX_OPT_HTTP2_BRIDGE)) {
    mod_config()->http2_bridge = util::strieq(optarg, "yes");

    return 0;
  }

  if (util::strieq(opt, SHRPX_OPT_CLIENT_PROXY)) {
    mod_config()->client_proxy = util::strieq(optarg, "yes");

    return 0;
  }

  if (util::strieq(opt, SHRPX_OPT_ADD_X_FORWARDED_FOR)) {
    mod_config()->add_x_forwarded_for = util::strieq(optarg, "yes");

    return 0;
  }

  if (util::strieq(opt, SHRPX_OPT_STRIP_INCOMING_X_FORWARDED_FOR)) {
    mod_config()->strip_incoming_x_forwarded_for = util::strieq(optarg, "yes");

    return 0;
  }

  if (util::strieq(opt, SHRPX_OPT_NO_VIA)) {
    mod_config()->no_via = util::strieq(optarg, "yes");

    return 0;
  }

  if (util::strieq(opt, SHRPX_OPT_FRONTEND_HTTP2_READ_TIMEOUT)) {
    return parse_timeval(&mod_config()->http2_upstream_read_timeout, opt,
                         optarg);
  }

  if (util::strieq(opt, SHRPX_OPT_FRONTEND_READ_TIMEOUT)) {
    return parse_timeval(&mod_config()->upstream_read_timeout, opt, optarg);
  }

  if (util::strieq(opt, SHRPX_OPT_FRONTEND_WRITE_TIMEOUT)) {
    return parse_timeval(&mod_config()->upstream_write_timeout, opt, optarg);
  }

  if (util::strieq(opt, SHRPX_OPT_BACKEND_READ_TIMEOUT)) {
    return parse_timeval(&mod_config()->downstream_read_timeout, opt, optarg);
  }

  if (util::strieq(opt, SHRPX_OPT_BACKEND_WRITE_TIMEOUT)) {
    return parse_timeval(&mod_config()->downstream_write_timeout, opt, optarg);
  }

  if (util::strieq(opt, SHRPX_OPT_STREAM_READ_TIMEOUT)) {
    return parse_timeval(&mod_config()->stream_read_timeout, opt, optarg);
  }

  if (util::strieq(opt, SHRPX_OPT_STREAM_WRITE_TIMEOUT)) {
    return parse_timeval(&mod_config()->stream_write_timeout, opt, optarg);
  }

  if (util::strieq(opt, SHRPX_OPT_ACCESSLOG_FILE)) {
    mod_config()->accesslog_file = strcopy(optarg);

    return 0;
  }

  if (util::strieq(opt, SHRPX_OPT_ACCESSLOG_SYSLOG)) {
    mod_config()->accesslog_syslog = util::strieq(optarg, "yes");

    return 0;
  }

  if (util::strieq(opt, SHRPX_OPT_ACCESSLOG_FORMAT)) {
    mod_config()->accesslog_format = parse_log_format(optarg);

    return 0;
  }

  if (util::strieq(opt, SHRPX_OPT_ERRORLOG_FILE)) {
    mod_config()->errorlog_file = strcopy(optarg);

    return 0;
  }

  if (util::strieq(opt, SHRPX_OPT_ERRORLOG_SYSLOG)) {
    mod_config()->errorlog_syslog = util::strieq(optarg, "yes");

    return 0;
  }

  if (util::strieq(opt, SHRPX_OPT_BACKEND_KEEP_ALIVE_TIMEOUT)) {
    return parse_timeval(&mod_config()->downstream_idle_read_timeout, opt,
                         optarg);
  }

  if (util::strieq(opt, SHRPX_OPT_FRONTEND_HTTP2_WINDOW_BITS) ||
      util::strieq(opt, SHRPX_OPT_BACKEND_HTTP2_WINDOW_BITS)) {

    size_t *resp;

    if (util::strieq(opt, SHRPX_OPT_FRONTEND_HTTP2_WINDOW_BITS)) {
      resp = &mod_config()->http2_upstream_window_bits;
    } else {
      resp = &mod_config()->http2_downstream_window_bits;
    }

    errno = 0;

    int n;

    if (parse_uint(&n, opt, optarg) != 0) {
      return -1;
    }

    if (n >= 31) {
      LOG(ERROR) << opt
                 << ": specify the integer in the range [0, 30], inclusive";
      return -1;
    }

    *resp = n;

    return 0;
  }

  if (util::strieq(opt, SHRPX_OPT_FRONTEND_HTTP2_CONNECTION_WINDOW_BITS) ||
      util::strieq(opt, SHRPX_OPT_BACKEND_HTTP2_CONNECTION_WINDOW_BITS)) {

    size_t *resp;

    if (util::strieq(opt, SHRPX_OPT_FRONTEND_HTTP2_CONNECTION_WINDOW_BITS)) {
      resp = &mod_config()->http2_upstream_connection_window_bits;
    } else {
      resp = &mod_config()->http2_downstream_connection_window_bits;
    }

    errno = 0;

    int n;

    if (parse_uint(&n, opt, optarg) != 0) {
      return -1;
    }

    if (n < 16 || n >= 31) {
      LOG(ERROR) << opt
                 << ": specify the integer in the range [16, 30], inclusive";
      return -1;
    }

    *resp = n;

    return 0;
  }

  if (util::strieq(opt, SHRPX_OPT_FRONTEND_NO_TLS)) {
    mod_config()->upstream_no_tls = util::strieq(optarg, "yes");

    return 0;
  }

  if (util::strieq(opt, SHRPX_OPT_BACKEND_NO_TLS)) {
    mod_config()->downstream_no_tls = util::strieq(optarg, "yes");

    return 0;
  }

  if (util::strieq(opt, SHRPX_OPT_BACKEND_TLS_SNI_FIELD)) {
    mod_config()->backend_tls_sni_name = strcopy(optarg);

    return 0;
  }

  if (util::strieq(opt, SHRPX_OPT_PID_FILE)) {
    mod_config()->pid_file = strcopy(optarg);

    return 0;
  }

  if (util::strieq(opt, SHRPX_OPT_USER)) {
    auto pwd = getpwnam(optarg);
    if (!pwd) {
      LOG(ERROR) << opt << ": failed to get uid from " << optarg << ": "
                 << strerror(errno);
      return -1;
    }
    mod_config()->uid = pwd->pw_uid;
    mod_config()->gid = pwd->pw_gid;

    return 0;
  }

  if (util::strieq(opt, SHRPX_OPT_PRIVATE_KEY_FILE)) {
    mod_config()->private_key_file = strcopy(optarg);

    return 0;
  }

  if (util::strieq(opt, SHRPX_OPT_PRIVATE_KEY_PASSWD_FILE)) {
    auto passwd = read_passwd_from_file(optarg);
    if (passwd.empty()) {
      LOG(ERROR) << opt << ": Couldn't read key file's passwd from " << optarg;
      return -1;
    }
    mod_config()->private_key_passwd = strcopy(passwd);

    return 0;
  }

  if (util::strieq(opt, SHRPX_OPT_CERTIFICATE_FILE)) {
    mod_config()->cert_file = strcopy(optarg);

    return 0;
  }

  if (util::strieq(opt, SHRPX_OPT_DH_PARAM_FILE)) {
    mod_config()->dh_param_file = strcopy(optarg);

    return 0;
  }

  if (util::strieq(opt, SHRPX_OPT_SUBCERT)) {
    // Private Key file and certificate file separated by ':'.
    const char *sp = strchr(optarg, ':');
    if (sp) {
      std::string keyfile(optarg, sp);
      // TODO Do we need private key for subcert?
      mod_config()->subcerts.emplace_back(keyfile, sp + 1);
    }

    return 0;
  }

  if (util::strieq(opt, SHRPX_OPT_SYSLOG_FACILITY)) {
    int facility = int_syslog_facility(optarg);
    if (facility == -1) {
      LOG(ERROR) << opt << ": Unknown syslog facility: " << optarg;
      return -1;
    }
    mod_config()->syslog_facility = facility;

    return 0;
  }

  if (util::strieq(opt, SHRPX_OPT_BACKLOG)) {
    int n;
    if (parse_int(&n, opt, optarg) != 0) {
      return -1;
    }

    if (n < -1) {
      LOG(ERROR) << opt << ": " << optarg << " is not allowed";

      return -1;
    }

    mod_config()->backlog = n;

    return 0;
  }

  if (util::strieq(opt, SHRPX_OPT_CIPHERS)) {
    mod_config()->ciphers = strcopy(optarg);

    return 0;
  }

  if (util::strieq(opt, SHRPX_OPT_CLIENT)) {
    mod_config()->client = util::strieq(optarg, "yes");

    return 0;
  }

  if (util::strieq(opt, SHRPX_OPT_INSECURE)) {
    mod_config()->insecure = util::strieq(optarg, "yes");

    return 0;
  }

  if (util::strieq(opt, SHRPX_OPT_CACERT)) {
    mod_config()->cacert = strcopy(optarg);

    return 0;
  }

  if (util::strieq(opt, SHRPX_OPT_BACKEND_IPV4)) {
    mod_config()->backend_ipv4 = util::strieq(optarg, "yes");

    return 0;
  }

  if (util::strieq(opt, SHRPX_OPT_BACKEND_IPV6)) {
    mod_config()->backend_ipv6 = util::strieq(optarg, "yes");

    return 0;
  }

  if (util::strieq(opt, SHRPX_OPT_BACKEND_HTTP_PROXY_URI)) {
    // parse URI and get hostname, port and optionally userinfo.
    http_parser_url u;
    memset(&u, 0, sizeof(u));
    int rv = http_parser_parse_url(optarg, strlen(optarg), 0, &u);
    if (rv == 0) {
      std::string val;
      if (u.field_set & UF_USERINFO) {
        http2::copy_url_component(val, &u, UF_USERINFO, optarg);
        // Surprisingly, u.field_set & UF_USERINFO is nonzero even if
        // userinfo component is empty string.
        if (!val.empty()) {
          val = util::percentDecode(val.begin(), val.end());
          mod_config()->downstream_http_proxy_userinfo = strcopy(val);
        }
      }
      if (u.field_set & UF_HOST) {
        http2::copy_url_component(val, &u, UF_HOST, optarg);
        mod_config()->downstream_http_proxy_host = strcopy(val);
      } else {
        LOG(ERROR) << opt << ": no hostname specified";
        return -1;
      }
      if (u.field_set & UF_PORT) {
        mod_config()->downstream_http_proxy_port = u.port;
      } else {
        LOG(ERROR) << opt << ": no port specified";
        return -1;
      }
    } else {
      LOG(ERROR) << opt << ": parse error";
      return -1;
    }

    return 0;
  }

  if (util::strieq(opt, SHRPX_OPT_READ_RATE)) {
    return parse_uint_with_unit(&mod_config()->read_rate, opt, optarg);
  }

  if (util::strieq(opt, SHRPX_OPT_READ_BURST)) {
    return parse_uint_with_unit(&mod_config()->read_burst, opt, optarg);
  }

  if (util::strieq(opt, SHRPX_OPT_WRITE_RATE)) {
    return parse_uint_with_unit(&mod_config()->write_rate, opt, optarg);
  }

  if (util::strieq(opt, SHRPX_OPT_WRITE_BURST)) {
    return parse_uint_with_unit(&mod_config()->write_burst, opt, optarg);
  }

  if (util::strieq(opt, SHRPX_OPT_WORKER_READ_RATE)) {
    LOG(WARN) << opt << ": not implemented yet";
    return parse_uint_with_unit(&mod_config()->worker_read_rate, opt, optarg);
  }

  if (util::strieq(opt, SHRPX_OPT_WORKER_READ_BURST)) {
    LOG(WARN) << opt << ": not implemented yet";
    return parse_uint_with_unit(&mod_config()->worker_read_burst, opt, optarg);
  }

  if (util::strieq(opt, SHRPX_OPT_WORKER_WRITE_RATE)) {
    LOG(WARN) << opt << ": not implemented yet";
    return parse_uint_with_unit(&mod_config()->worker_write_rate, opt, optarg);
  }

  if (util::strieq(opt, SHRPX_OPT_WORKER_WRITE_BURST)) {
    LOG(WARN) << opt << ": not implemented yet";
    return parse_uint_with_unit(&mod_config()->worker_write_burst, opt, optarg);
  }

  if (util::strieq(opt, SHRPX_OPT_NPN_LIST)) {
    clear_config_str_list(mod_config()->npn_list);

    mod_config()->npn_list = parse_config_str_list(optarg);

    return 0;
  }

  if (util::strieq(opt, SHRPX_OPT_TLS_PROTO_LIST)) {
    clear_config_str_list(mod_config()->tls_proto_list);

    mod_config()->tls_proto_list = parse_config_str_list(optarg);

    return 0;
  }

  if (util::strieq(opt, SHRPX_OPT_VERIFY_CLIENT)) {
    mod_config()->verify_client = util::strieq(optarg, "yes");

    return 0;
  }

  if (util::strieq(opt, SHRPX_OPT_VERIFY_CLIENT_CACERT)) {
    mod_config()->verify_client_cacert = strcopy(optarg);

    return 0;
  }

  if (util::strieq(opt, SHRPX_OPT_CLIENT_PRIVATE_KEY_FILE)) {
    mod_config()->client_private_key_file = strcopy(optarg);

    return 0;
  }

  if (util::strieq(opt, SHRPX_OPT_CLIENT_CERT_FILE)) {
    mod_config()->client_cert_file = strcopy(optarg);

    return 0;
  }

  if (util::strieq(opt, SHRPX_OPT_FRONTEND_HTTP2_DUMP_REQUEST_HEADER)) {
    mod_config()->http2_upstream_dump_request_header_file = strcopy(optarg);

    return 0;
  }

  if (util::strieq(opt, SHRPX_OPT_FRONTEND_HTTP2_DUMP_RESPONSE_HEADER)) {
    mod_config()->http2_upstream_dump_response_header_file = strcopy(optarg);

    return 0;
  }

  if (util::strieq(opt, SHRPX_OPT_HTTP2_NO_COOKIE_CRUMBLING)) {
    mod_config()->http2_no_cookie_crumbling = util::strieq(optarg, "yes");

    return 0;
  }

  if (util::strieq(opt, SHRPX_OPT_FRONTEND_FRAME_DEBUG)) {
    mod_config()->upstream_frame_debug = util::strieq(optarg, "yes");

    return 0;
  }

  if (util::strieq(opt, SHRPX_OPT_PADDING)) {
    return parse_uint(&mod_config()->padding, opt, optarg);
  }

  if (util::strieq(opt, SHRPX_OPT_ALTSVC)) {
    auto tokens = parse_config_str_list(optarg);

    if (tokens.size() < 2) {
      // Requires at least protocol_id and port
      LOG(ERROR) << opt << ": too few parameters: " << optarg;
      return -1;
    }

    if (tokens.size() > 4) {
      // We only need protocol_id, port, host and origin
      LOG(ERROR) << opt << ": too many parameters: " << optarg;
      return -1;
    }

    int port;

    if (parse_uint(&port, opt, tokens[1]) != 0) {
      return -1;
    }

    if (port < 1 ||
        port > static_cast<int>(std::numeric_limits<uint16_t>::max())) {
      LOG(ERROR) << opt << ": port is invalid: " << tokens[1];
      return -1;
    }

    AltSvc altsvc;

    altsvc.port = port;

    altsvc.protocol_id = tokens[0];
    altsvc.protocol_id_len = strlen(altsvc.protocol_id);

    if (tokens.size() > 2) {
      altsvc.host = tokens[2];
      altsvc.host_len = strlen(altsvc.host);

      if (tokens.size() > 3) {
        altsvc.origin = tokens[3];
        altsvc.origin_len = strlen(altsvc.origin);
      }
    }

    mod_config()->altsvcs.push_back(std::move(altsvc));

    return 0;
  }

  if (util::strieq(opt, SHRPX_OPT_ADD_RESPONSE_HEADER)) {
    auto p = parse_header(optarg);
    if (p.first.empty()) {
      LOG(ERROR) << opt << ": header field name is empty: " << optarg;
      return -1;
    }
    mod_config()->add_response_headers.push_back(std::move(p));

    return 0;
  }

  if (util::strieq(opt, SHRPX_OPT_WORKER_FRONTEND_CONNECTIONS)) {
    return parse_uint(&mod_config()->worker_frontend_connections, opt, optarg);
  }

  if (util::strieq(opt, SHRPX_OPT_NO_LOCATION_REWRITE)) {
    mod_config()->no_location_rewrite = util::strieq(optarg, "yes");

    return 0;
  }

  if (util::strieq(opt, SHRPX_OPT_BACKEND_HTTP1_CONNECTIONS_PER_HOST)) {
    int n;

    if (parse_uint(&n, opt, optarg) != 0) {
      return -1;
    }

    if (n == 0) {
      LOG(ERROR) << opt << ": specify an integer strictly more than 0";

      return -1;
    }

    mod_config()->downstream_connections_per_host = n;

    return 0;
  }

  if (util::strieq(opt, SHRPX_OPT_BACKEND_HTTP1_CONNECTIONS_PER_FRONTEND)) {
    return parse_uint(&mod_config()->downstream_connections_per_frontend, opt,
                      optarg);
  }

  if (util::strieq(opt, SHRPX_OPT_LISTENER_DISABLE_TIMEOUT)) {
    return parse_timeval(&mod_config()->listener_disable_timeout, opt, optarg);
  }

  if (util::strieq(opt, SHRPX_OPT_TLS_TICKET_KEY_FILE)) {
    mod_config()->tls_ticket_key_files.push_back(optarg);
    return 0;
  }

  if (util::strieq(opt, SHRPX_OPT_RLIMIT_NOFILE)) {
    int n;

    if (parse_uint(&n, opt, optarg) != 0) {
      return -1;
    }

    if (n < 0) {
      LOG(ERROR) << opt << ": specify the integer more than or equal to 0";

      return -1;
    }

    mod_config()->rlimit_nofile = n;

    return 0;
  }

  if (util::strieq(opt, SHRPX_OPT_BACKEND_REQUEST_BUFFER) ||
      util::strieq(opt, SHRPX_OPT_BACKEND_RESPONSE_BUFFER)) {
    size_t n;
    if (parse_uint_with_unit(&n, opt, optarg) != 0) {
      return -1;
    }

    if (n == 0) {
      LOG(ERROR) << opt << ": specify an integer strictly more than 0";

      return -1;
    }

    if (util::strieq(opt, SHRPX_OPT_BACKEND_REQUEST_BUFFER)) {
      mod_config()->downstream_request_buffer_size = n;
    } else {
      mod_config()->downstream_response_buffer_size = n;
    }

    return 0;
  }

  if (util::strieq(opt, SHRPX_OPT_TLS_CTX_PER_WORKER)) {
    mod_config()->tls_ctx_per_worker = util::strieq(optarg, "yes");

    return 0;
  }

  if (util::strieq(opt, "conf")) {
    LOG(WARN) << "conf: ignored";

    return 0;
  }

  LOG(ERROR) << "Unknown option: " << opt;

  return -1;
}

int load_config(const char *filename) {
  std::ifstream in(filename, std::ios::binary);
  if (!in) {
    LOG(ERROR) << "Could not open config file " << filename;
    return -1;
  }
  std::string line;
  int linenum = 0;
  while (std::getline(in, line)) {
    ++linenum;
    if (line.empty() || line[0] == '#') {
      continue;
    }
    size_t i;
    size_t size = line.size();
    for (i = 0; i < size && line[i] != '='; ++i)
      ;
    if (i == size) {
      LOG(ERROR) << "Bad configuration format at line " << linenum;
      return -1;
    }
    line[i] = '\0';
    auto s = line.c_str();
    if (parse_config(s, s + i + 1) == -1) {
      return -1;
    }
  }
  return 0;
}

const char *str_syslog_facility(int facility) {
  switch (facility) {
  case (LOG_AUTH):
    return "auth";
  case (LOG_AUTHPRIV):
    return "authpriv";
  case (LOG_CRON):
    return "cron";
  case (LOG_DAEMON):
    return "daemon";
  case (LOG_FTP):
    return "ftp";
  case (LOG_KERN):
    return "kern";
  case (LOG_LOCAL0):
    return "local0";
  case (LOG_LOCAL1):
    return "local1";
  case (LOG_LOCAL2):
    return "local2";
  case (LOG_LOCAL3):
    return "local3";
  case (LOG_LOCAL4):
    return "local4";
  case (LOG_LOCAL5):
    return "local5";
  case (LOG_LOCAL6):
    return "local6";
  case (LOG_LOCAL7):
    return "local7";
  case (LOG_LPR):
    return "lpr";
  case (LOG_MAIL):
    return "mail";
  case (LOG_SYSLOG):
    return "syslog";
  case (LOG_USER):
    return "user";
  case (LOG_UUCP):
    return "uucp";
  default:
    return "(unknown)";
  }
}

int int_syslog_facility(const char *strfacility) {
  if (util::strieq(strfacility, "auth")) {
    return LOG_AUTH;
  }

  if (util::strieq(strfacility, "authpriv")) {
    return LOG_AUTHPRIV;
  }

  if (util::strieq(strfacility, "cron")) {
    return LOG_CRON;
  }

  if (util::strieq(strfacility, "daemon")) {
    return LOG_DAEMON;
  }

  if (util::strieq(strfacility, "ftp")) {
    return LOG_FTP;
  }

  if (util::strieq(strfacility, "kern")) {
    return LOG_KERN;
  }

  if (util::strieq(strfacility, "local0")) {
    return LOG_LOCAL0;
  }

  if (util::strieq(strfacility, "local1")) {
    return LOG_LOCAL1;
  }

  if (util::strieq(strfacility, "local2")) {
    return LOG_LOCAL2;
  }

  if (util::strieq(strfacility, "local3")) {
    return LOG_LOCAL3;
  }

  if (util::strieq(strfacility, "local4")) {
    return LOG_LOCAL4;
  }

  if (util::strieq(strfacility, "local5")) {
    return LOG_LOCAL5;
  }

  if (util::strieq(strfacility, "local6")) {
    return LOG_LOCAL6;
  }

  if (util::strieq(strfacility, "local7")) {
    return LOG_LOCAL7;
  }

  if (util::strieq(strfacility, "lpr")) {
    return LOG_LPR;
  }

  if (util::strieq(strfacility, "mail")) {
    return LOG_MAIL;
  }

  if (util::strieq(strfacility, "news")) {
    return LOG_NEWS;
  }

  if (util::strieq(strfacility, "syslog")) {
    return LOG_SYSLOG;
  }

  if (util::strieq(strfacility, "user")) {
    return LOG_USER;
  }

  if (util::strieq(strfacility, "uucp")) {
    return LOG_UUCP;
  }

  return -1;
}

} // namespace shrpx