Qthread socket debugging

blocking_action.c

#include <stdio.h>  //printf
#include <string.h> //strcpy
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
#include <netdb.h>
#include <fcntl.h>
#include <stdlib.h>
#include <errno.h>
#include <qthread/io.h>

typedef struct sockaddr_storage sys_sockaddr_storage_t;

int main(int argc, char *argv[])
{
  int socket_desc;
  int iport = 8000;

  //Create socket
  const int val_sock = AF_INET;
  socket_desc = socket(val_sock, SOCK_STREAM|SOCK_NONBLOCK, 0);
  if (socket_desc == -1)
  {
    printf("Could not create socket");
  }

  int flags = fcntl(socket_desc, F_GETFL, 0);
  fcntl(socket_desc, F_SETFL, flags | O_NONBLOCK);

  // fill in address
  sys_sockaddr_storage_t x;
  memset(&x, 0, sizeof(x));
  if(val_sock == AF_INET){
    struct sockaddr_in *x1 = (struct sockaddr_in *)&x;
    x1->sin_family = AF_INET;
    x1->sin_port = htons(iport);
    x1->sin_addr.s_addr = htonl(INADDR_LOOPBACK);
  }
  else {
    struct sockaddr_in6 *x1 = (struct sockaddr_in6 *)&x;
    x1->sin6_family = AF_INET6;
    x1->sin6_port = htons(iport);
    x1->sin6_addr = in6addr_loopback;
  }

  // extract out data
  char address[NI_MAXHOST], port[NI_MAXSERV];
  int err = getnameinfo((struct sockaddr*)&x, sizeof(sys_sockaddr_storage_t), address, sizeof(address), port, sizeof(port), NI_NUMERICHOST | NI_NUMERICSERV);
  puts(address);
  puts(port);

  int n;

  qt_begin_blocking_action();
  if ((n = connect(socket_desc, (struct sockaddr *)&x, sizeof(x))) < 0)
  {
    if(errno != EINPROGRESS){
      puts(strerror(errno));
      exit(0);
    }
  }
  qt_end_blocking_action();

  puts("connect tried");

  if(n == 0){
    printf("connect success");
    exit(0);
  }

  fd_set rset, wset;
  FD_ZERO(&wset);
  FD_ZERO(&rset);
  FD_SET(socket_desc, &rset);
  FD_SET(socket_desc, &wset);
  struct timeval tval;
  tval.tv_sec = 10;
  tval.tv_usec = 0;


  qt_begin_blocking_action();
  if((n = select(socket_desc + 1, NULL, &wset, NULL, &tval)) == 0){
    puts(strerror(ETIMEDOUT));
    exit(0);
  }
  qt_end_blocking_action();
  puts("select tried");


  if(n < 0){
    puts(strerror(errno));
    exit(0);
  }
  puts("select error checked");


  if(FD_ISSET(socket_desc,&rset) || FD_ISSET(socket_desc, &wset)) {
    socklen_t len;
    if(getpeername(socket_desc, (struct sockaddr *)&x, &len) < 0){
      puts("peername fail");
      puts(strerror(errno));
      exit(0);
      if(errno == ENOTCONN){
        int err_t;
        socklen_t len = sizeof(err_t);
        if(getsockopt(socket_desc, SOL_SOCKET, SO_ERROR, &err_t, &len) < 0) {
          puts("getsockopt fail");
          close(socket_desc);
          puts(strerror(errno));
          exit(0);
        }
        if(err_t){
          close(socket_desc);
          puts(strerror(err_t));
          exit(0);
        }
      }
    }
  }
  else {
    close(socket_desc);
    puts("Select error: socketFd not set");
    exit(0);
  }
  puts("rset wset pass");


  printf("connect success");
}

connect.c

#include <stdio.h>  //printf
#include <string.h> //strcpy
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
#include <netdb.h>
#include <fcntl.h>
#include <stdlib.h>
#include <errno.h>

typedef struct sockaddr_storage sys_sockaddr_storage_t;

int main(int argc, char *argv[])
{
  int socket_desc;
  int iport = 8000;

  //Create socket
  const int val_sock = AF_INET;
  socket_desc = socket(val_sock, SOCK_STREAM|SOCK_NONBLOCK, 0);
  if (socket_desc == -1)
  {
    printf("Could not create socket");
  }

  int flags = fcntl(socket_desc, F_GETFL, 0);
  fcntl(socket_desc, F_SETFL, flags | O_NONBLOCK);

  // fill in address
  sys_sockaddr_storage_t x;
  memset(&x, 0, sizeof(x));
  if(val_sock == AF_INET){
    struct sockaddr_in *x1 = (struct sockaddr_in *)&x;
    x1->sin_family = AF_INET;
    x1->sin_port = htons(iport);
    x1->sin_addr.s_addr = htonl(INADDR_LOOPBACK);
  }
  else {
    struct sockaddr_in6 *x1 = (struct sockaddr_in6 *)&x;
    x1->sin6_family = AF_INET6;
    x1->sin6_port = htons(iport);
    x1->sin6_addr = in6addr_loopback;
  }

  // extract out data
  char address[NI_MAXHOST], port[NI_MAXSERV];
  int err = getnameinfo((struct sockaddr*)&x, sizeof(sys_sockaddr_storage_t), address, sizeof(address), port, sizeof(port), NI_NUMERICHOST | NI_NUMERICSERV);
  puts(address);
  puts(port);

  int n;

  if ((n = connect(socket_desc, (struct sockaddr *)&x, sizeof(x))) < 0)
  {
    if(errno != EINPROGRESS){
      puts(strerror(errno));
      exit(0);
    }
  }

  puts("connect tried");

  if(n == 0){
    printf("connect success");
    exit(0);
  }

  fd_set rset, wset;
  FD_ZERO(&wset);
  FD_ZERO(&rset);
  FD_SET(socket_desc, &rset);
  FD_SET(socket_desc, &wset);
  struct timeval tval;
  tval.tv_sec = 10;
  tval.tv_usec = 0;


  if((n = select(socket_desc + 1, NULL, &wset, NULL, &tval)) == 0){
    puts(strerror(ETIMEDOUT));
    exit(0);
  }
  puts("select tried");


  if(n < 0){
    puts(strerror(errno));
    exit(0);
  }
  puts("select error checked");


  if(FD_ISSET(socket_desc,&rset) || FD_ISSET(socket_desc, &wset)) {
    socklen_t len;
    if(getpeername(socket_desc, (struct sockaddr *)&x, &len) < 0){
      puts("peername fail");
      puts(strerror(errno));
      exit(0);
      if(errno == ENOTCONN){
        int err_t;
        socklen_t len = sizeof(err_t);
        if(getsockopt(socket_desc, SOL_SOCKET, SO_ERROR, &err_t, &len) < 0) {
          puts("getsockopt fail");
          close(socket_desc);
          puts(strerror(errno));
          exit(0);
        }
        if(err_t){
          close(socket_desc);
          puts(strerror(err_t));
          exit(0);
        }
      }
    }
  }
  else {
    close(socket_desc);
    puts("Select error: socketFd not set");
    exit(0);
  }
  puts("rset wset pass");


  printf("connect success");
}

qtconnect.c

#include <stdio.h>  //printf
#include <string.h> //strcpy
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
#include <netdb.h>
#include <fcntl.h>
#include <stdlib.h>
#include <errno.h>
#include <qthread/io.h>
#include <qthread/qt_syscalls.h>
#include <qthread.h>

typedef struct sockaddr_storage sys_sockaddr_storage_t;

int main(int argc, char *argv[])
{
  int socket_desc;
  int iport = 8000;

  //Create socket
  const int val_sock = AF_INET;
  socket_desc = socket(val_sock, SOCK_STREAM|SOCK_NONBLOCK, 0);
  if (socket_desc == -1)
  {
    printf("Could not create socket");
  }

  int flags = fcntl(socket_desc, F_GETFL, 0);
  fcntl(socket_desc, F_SETFL, flags | O_NONBLOCK);

  // fill in address
  sys_sockaddr_storage_t x;
  memset(&x, 0, sizeof(x));
  if(val_sock == AF_INET){
    struct sockaddr_in *x1 = (struct sockaddr_in *)&x;
    x1->sin_family = AF_INET;
    x1->sin_port = htons(iport);
    x1->sin_addr.s_addr = htonl(INADDR_LOOPBACK);
  }
  else {
    struct sockaddr_in6 *x1 = (struct sockaddr_in6 *)&x;
    x1->sin6_family = AF_INET6;
    x1->sin6_port = htons(iport);
    x1->sin6_addr = in6addr_loopback;
  }

  // extract out data
  char address[NI_MAXHOST], port[NI_MAXSERV];
  int err = getnameinfo((struct sockaddr*)&x, sizeof(sys_sockaddr_storage_t), address, sizeof(address), port, sizeof(port), NI_NUMERICHOST | NI_NUMERICSERV);
  puts(address);
  puts(port);

  int n;

  if ((n = qt_connect(socket_desc, (struct sockaddr *)&x, sizeof(x))) < 0)
  {
    if(errno != EINPROGRESS){
      puts(strerror(errno));
      exit(0);
    }
  }

  puts("connect tried");

  if(n == 0){
    printf("connect success");
    exit(0);
  }

  fd_set rset, wset;
  FD_ZERO(&wset);
  FD_ZERO(&rset);
  FD_SET(socket_desc, &rset);
  FD_SET(socket_desc, &wset);
  struct timeval tval;
  tval.tv_sec = 10;
  tval.tv_usec = 0;


  if((n = qt_select(socket_desc + 1, NULL, &wset, NULL, &tval)) == 0){
    puts(strerror(ETIMEDOUT));
    exit(0);
  }
  puts("select tried");


  if(n < 0){
    puts(strerror(errno));
    exit(0);
  }
  puts("select error checked");


  if(FD_ISSET(socket_desc,&rset) || FD_ISSET(socket_desc, &wset)) {
    socklen_t len;
    if(getpeername(socket_desc, (struct sockaddr *)&x, &len) < 0){
      puts("peername fail");
      puts(strerror(errno));
      exit(0);
      if(errno == ENOTCONN){
        int err_t;
        socklen_t len = sizeof(err_t);
        if(getsockopt(socket_desc, SOL_SOCKET, SO_ERROR, &err_t, &len) < 0) {
          puts("getsockopt fail");
          close(socket_desc);
          puts(strerror(errno));
          exit(0);
        }
        if(err_t){
          close(socket_desc);
          puts(strerror(err_t));
          exit(0);
        }
      }
    }
  }
  else {
    close(socket_desc);
    puts("Select error: socketFd not set");
    exit(0);
  }
  puts("rset wset pass");


  printf("connect success");
}

blocking_action.c and connect.c are the working ones whereas qtconnect.c throws a segfault if either of qt_connect or qt_select is being called in the file.

running Valgrind shows the error is at line 33 which is working perfectly in the other two files.

for compiling the source file using qthreads:

LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/local/lib
export LD_LIBRARY_PATH
gcc -lqthread -lpthread -g -o qtconnect qtconnect.c

import select
import socket
from time import sleep

HEADER_LENGTH = 10

IP = "127.0.0.1"
PORT = 8000

#ipv4 and tcp
server_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
#reconnect to same server
server_socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
server_socket.bind((IP, PORT))
#queue length
server_socket.listen()
sockets_list = [server_socket]

clients = {}

print(f'Listening for connections on {IP}:{PORT}...')

while True:
    read_sockets, _, exception_sockets = select.select(
        sockets_list, [], sockets_list)
    if server_socket in read_sockets:
      client_socket, client_address = server_socket.accept()
      print('Accepted new connection from {}:{}'.format(*client_address))
      client_socket.send("greb".encode())
      sleep(4)
    break

Sample server code