conky/src/read_tcpip.cc

/*
 *
 * Conky, a system monitor, based on torsmo
 *
 * Any original torsmo code is licensed under the BSD license
 *
 * All code written since the fork of torsmo is licensed under the GPL
 *
 * Please see COPYING for details
 *
 * Copyright (c) 2004, Hannu Saransaari and Lauri Hakkarainen
 * Copyright (c) 2005-2021 Brenden Matthews, Philip Kovacs, et. al.
 *	(see AUTHORS)
 * All rights reserved.
 *
 * 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 3 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, see <http://www.gnu.org/licenses/>.
 *
 */

#include <fcntl.h>
#include <netdb.h>
#include <netinet/in.h>
#include <sys/time.h>
#include <unistd.h>
#include <cerrno>
#include <cinttypes>
#include <cstdlib>
#include <string>
#include "conky.h"
#include "logging.h"
#include "text_object.h"

#ifndef SOCK_CLOEXEC
#define SOCK_CLOEXEC O_CLOEXEC
#endif /* SOCK_CLOEXEC */

struct read_tcpip_data {
  char *host;
  unsigned int port;
};

void parse_read_tcpip_arg(struct text_object *obj, const char *arg,
                          void *free_at_crash) {
  struct read_tcpip_data *rtd;

  rtd = static_cast<struct read_tcpip_data *>(
      malloc(sizeof(struct read_tcpip_data)));
  memset(rtd, 0, sizeof(struct read_tcpip_data));

  rtd->host = static_cast<char *>(malloc(text_buffer_size.get(*state)));
  sscanf(arg, "%s", rtd->host);
  sscanf(arg + strlen(rtd->host), "%u", &(rtd->port));
  if (rtd->port == 0) {
    rtd->port = strtol(rtd->host, nullptr, 10);
    strncpy(rtd->host, "localhost", 10);
  }
  if (rtd->port < 1 || rtd->port > 65535) {
    CRIT_ERR(obj, free_at_crash,
             "read_tcp and read_udp need a port from 1 to 65535 as argument");
  }

  obj->data.opaque = rtd;
}

void parse_tcp_ping_arg(struct text_object *obj, const char *arg,
                        void *free_at_crash) {
#define DEFAULT_TCP_PING_PORT 80
  struct sockaddr_in *addr;
  char *hostname;
  struct hostent *he;

  addr = static_cast<struct sockaddr_in *>(malloc(sizeof(struct sockaddr_in)));
  obj->data.opaque = addr;
  memset(addr, 0, sizeof(struct sockaddr_in));
  hostname = static_cast<char *>(malloc(strlen(arg) + 1));
  switch (sscanf(arg, "%s %" SCNu16, hostname, &(addr->sin_port))) {
    case 1:
      addr->sin_port = DEFAULT_TCP_PING_PORT;
      break;
    case 2:
      break;
    default:  // this point should never be reached
      free(hostname);
      CRIT_ERR(obj, free_at_crash, "tcp_ping: Reading arguments failed");
  }
  if ((he = gethostbyname(hostname)) == nullptr) {
    NORM_ERR("tcp_ping: Problem with resolving '%s', using 'localhost' instead",
             hostname);
    if ((he = gethostbyname("localhost")) == nullptr) {
      free(hostname);
      CRIT_ERR(obj, free_at_crash,
               "tcp_ping: Resolving 'localhost' also failed");
    }
  }
  if (he != nullptr) {
    free(hostname);
    addr->sin_port = htons(addr->sin_port);
    addr->sin_family = he->h_addrtype;
    memcpy(&(addr->sin_addr), he->h_addr, he->h_length);
  }
}

void print_tcp_ping(struct text_object *obj, char *p, unsigned int p_max_size) {
  struct timeval tv1 {
  }, tv2{}, timeout{};
  auto *addr = static_cast<struct sockaddr_in *>(obj->data.opaque);
  int addrlen = sizeof(struct sockaddr);
  int sock = socket(addr->sin_family, SOCK_STREAM | SOCK_CLOEXEC, IPPROTO_TCP);
  unsigned long long usecdiff;
  fd_set writefds;

  if (sock != -1) {
    fcntl(sock, F_SETFL, O_NONBLOCK | fcntl(sock, F_GETFL));

    FD_ZERO(&writefds);
    FD_SET(sock, &writefds);
#define TCP_PING_TIMEOUT 10
    timeout.tv_sec = TCP_PING_TIMEOUT;
    timeout.tv_usec = (TCP_PING_TIMEOUT - timeout.tv_sec) * 1000000;
    connect(sock, reinterpret_cast<struct sockaddr *>(addr),
            addrlen);  // this will "fail" because sock is non-blocking
    if (errno == EINPROGRESS) {  // but EINPROGRESS is only a "false fail"
      gettimeofday(&tv1, nullptr);
      if (select(sock + 1, nullptr, &writefds, nullptr, &timeout) != -1) {
        gettimeofday(&tv2, nullptr);
        usecdiff =
            ((tv2.tv_sec - tv1.tv_sec) * 1000000) + tv2.tv_usec - tv1.tv_usec;
        if (usecdiff <= TCP_PING_TIMEOUT * 1000000) {
          snprintf(p, p_max_size, "%llu", (usecdiff / 1000U));
        } else {
#define TCP_PING_FAILED "down"
          snprintf(p, p_max_size, "%s", TCP_PING_FAILED);
        }
      } else {
        NORM_ERR("tcp_ping: Couldn't wait on the 'pong'");
      }
    } else {
      NORM_ERR("tcp_ping: Couldn't start connection");
    }
    close(sock);
  } else {
    NORM_ERR("tcp_ping: Couldn't create socket");
  }
}

void print_read_tcpip(struct text_object *obj, char *p, int p_max_size,
                      int protocol) {
  int sock, received;
  fd_set readfds;
  struct timeval tv {};
  auto *rtd = static_cast<struct read_tcpip_data *>(obj->data.opaque);
  struct addrinfo hints {};
  struct addrinfo *airesult, *rp;
  char portbuf[8];

  if (rtd == nullptr) { return; }

  memset(&hints, 0, sizeof(struct addrinfo));
  hints.ai_family = AF_UNSPEC;
  hints.ai_socktype = protocol == IPPROTO_TCP ? SOCK_STREAM : SOCK_DGRAM;
  hints.ai_flags = 0;
  hints.ai_protocol = protocol;
  snprintf(portbuf, 8, "%u", rtd->port);
  if (getaddrinfo(rtd->host, portbuf, &hints, &airesult) != 0) {
    NORM_ERR("%s: Problem with resolving the hostname",
             protocol == IPPROTO_TCP ? "read_tcp" : "read_udp");
    return;
  }
  for (rp = airesult; rp != nullptr; rp = rp->ai_next) {
    sock = socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol);
    if (sock == -1) { continue; }
    if (connect(sock, rp->ai_addr, rp->ai_addrlen) != -1) { break; }
    close(sock);
    return;
  }
  freeaddrinfo(airesult);
  if (rp == nullptr) {
    if (protocol == IPPROTO_TCP) {
      NORM_ERR("read_tcp: Couldn't create a connection");
    } else {
      NORM_ERR("read_udp: Couldn't listen");  // other error because udp is
                                              // connectionless
    }
    return;
  }
  if (protocol == IPPROTO_UDP) {
    // when using udp send a zero-length packet to let the other end know of our
    // existence
    if (write(sock, nullptr, 0) < 0) {
      NORM_ERR("read_udp: Couldn't create a empty package");
    }
  }
  FD_ZERO(&readfds);
  FD_SET(sock, &readfds);
  tv.tv_sec = 1;
  tv.tv_usec = 0;
  if (select(sock + 1, &readfds, nullptr, nullptr, &tv) > 0) {
    received = recv(sock, p, p_max_size, 0);
    if (received != -1) {
      p[received] = 0;
    } else {
      p[0] = 0;
    }
  }
  close(sock);
}

void print_read_tcp(struct text_object *obj, char *p, unsigned int p_max_size) {
  print_read_tcpip(obj, p, p_max_size, IPPROTO_TCP);
}

void print_read_udp(struct text_object *obj, char *p, unsigned int p_max_size) {
  print_read_tcpip(obj, p, p_max_size, IPPROTO_UDP);
}

void free_read_tcpip(struct text_object *obj) {
  auto *rtd = static_cast<struct read_tcpip_data *>(obj->data.opaque);

  if (rtd == nullptr) { return; }

  free_and_zero(rtd->host);
  free_and_zero(obj->data.opaque);
}

void free_tcp_ping(struct text_object *obj) {
  auto *addr = static_cast<struct sockaddr_in *>(obj->data.opaque);

  if (addr == nullptr) { return; }

  free_and_zero(obj->data.opaque);
}