WinSock2+FILE I/Oを利用したネットワークサーバのサンプル

README.md

what is this?

WinSock2+FILE I/Oを利用したネットワークサーバのサンプル

参考にしたページの一部

• http://www.ne.jp/asahi/hishidama/home/tech/lang/socket.html
• http://d.hatena.ne.jp/winebarrel/20080315/p2
• http://mattn.kaoriya.net/software/windows/20071001121756.htm

echo-server.c

#include "server.h"
#include <stdio.h>
#include <string.h>
#include <ctype.h>

#define RCVBUFSIZE 16

char *upcase(char *s) {
  for (char *p=s; *p; ++p)
    *p = toupper(*p);
  return s;
}

char *chomp(char *s) {
  char *eol = strpbrk(s, "\n");
  if (eol) *eol = '\0';
  return s;
}

void execute_echo(FILE *r, FILE *w) {
  char line[RCVBUFSIZE+1] = {0};
  while (fgets(line, sizeof(line), r) != NULL) {
    //fprintf(w, "%s", upcase(line));
    size_t len = strlen(line);
    size_t n = fwrite(upcase(line), 1, len, w);
    if (n < len) {
      debug("write %"PRIdSIZE" byte, but expect %"PRIdSIZE" byte: '%s\\n'\n", n, len, chomp(line));
    }
  }
}

int main() {
  start_server("1234", execute_echo);
  return 0;
}

http-server.c

/**
 * http-server.c
 *
 * Usage:
 *
 * [server]$ make http-server
 * [server]$ ./http-server 4711
 * [client]$ curl -v localhost 4711
 */

#include "server.h"

#include <stdio.h>
#include <string.h>

#define RCVBUFSIZE 255

void usage(char *progname)
{
  fprintf(stderr, "Usage: %s PORT\n", progname);
}

void execute_http_request(FILE *r, FILE *w)
{
  char buf[RCVBUFSIZE + 1] = {0};

  // read headers (ignored)
  while (fgets(buf, RCVBUFSIZE + 1, r) != NULL) {
    if (strcmp(buf, "\r\n") == 0 || strcmp(buf, "\n") == 0) break;
    debug("recv: [%s]\r\n", buf);
  }

  char contents[] = "Hello, world!";

  fprintf(w, "HTTP/1.0 200 OK\r\n");
  fprintf(w, "Server: simple httpd 0.1\r\n");
  fprintf(w, "Content-Type: text/plain\r\n");
  fprintf(w, "Content-Length: %"PRIdSIZE"\r\n", strlen(contents));
  fprintf(w, "\r\n");
  fprintf(w, "%s", contents);

  return;
}

int main(int argc, char *argv[])
{
  if (argc < 2) {
    usage(argv[0]);
    return 1;
  }

  char *service = argv[1];

  start_server(service, execute_http_request);

  return 0;
}

Makefile

ifeq ($(OS),Windows_NT)
CC = gcc
endif

TARGET := http-server echo-server
CFLAGS := -std=gnu99 -Wall -Werror -g3 -O0 \
	$(if $(findstring MINGW,$(MSYSTEM)),-Wno-pedantic-ms-format)
LDLIBS := $(if $(findstring MINGW,$(MSYSTEM)),-lws2_32)

default: $(TARGET)

http-server: http-server.o server.o
echo-server: echo-server.o server.o

clean:
	$(RM) *.o $(TARGET)

server.c

// server.c

#include "server.h"

#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#ifdef _WIN32
#define WIN32_LEAN_AND_MEAN
#include <winsock2.h>
#include <ws2tcpip.h>
#include <mswsock.h>
#include <io.h>                 // _open_osfhandle
typedef int socklen_t;
#else  // unix
#include <sys/socket.h>
#include <sys/types.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <unistd.h>
typedef int SOCKET;
#define closesocket close
#define SOCKET_ERROR (-1)
#define INVALID_SOCKET ((SOCKET)(~0))
#endif

#define MAX_BACKLOG 5

void socket_startup()
{
#ifdef _WIN32
  WSADATA wsaData;
  if (WSAStartup(MAKEWORD(2, 2), &wsaData) != 0) {
    WSACleanup();
    exit(EXIT_FAILURE);
  }

  int opt = SO_SYNCHRONOUS_NONALERT;
  setsockopt(INVALID_SOCKET, SOL_SOCKET, SO_OPENTYPE, (char *)&opt, sizeof(opt));
#endif
}

void socket_cleanup()
{
#ifdef _WIN32
  WSACleanup();
#endif
}

static char *sockaddr_info(const struct sockaddr *sa)
{
  static char buf[NI_MAXHOST + NI_MAXSERV + 2] = {0}; // "HOST:PORT\0"
  char hostname[NI_MAXHOST] = {0};
  char servname[NI_MAXSERV] = {0};
  size_t addrlen;
  int rc;

  if (sa->sa_family == AF_INET)
    addrlen = sizeof(struct sockaddr_in);
  else // AF_INET6
    addrlen = sizeof(struct sockaddr_in6);

  rc = getnameinfo(sa, addrlen,
                   hostname, sizeof(hostname),
                   servname, sizeof(servname),
                   NI_NUMERICHOST | NI_NUMERICSERV);
  if (rc != 0) {
    debug("getnameinfo: %s\n", gai_strerror(rc));
    return NULL;
  }

  snprintf(buf, sizeof(buf), "%s:%s", hostname, servname);

  return buf;
}

int tcp_listen(const char *nodename, const char *service)
{
  struct addrinfo hints;
  struct addrinfo *ans = NULL;
  int sockfd, err;

  memset(&hints, 0, sizeof(hints));
  hints.ai_family = AF_UNSPEC;  /* Allow IPv4 or IPv6 */
  hints.ai_flags = AI_PASSIVE;
  hints.ai_socktype = SOCK_STREAM;

  err = getaddrinfo(nodename, service, &hints, &ans);
  if (err != 0) {
    debug("getaddrinfo: %s\n", gai_strerror(err));
    return -1;
  }

/* #ifdef _WIN32
 *   sockfd = WSASocket(ans->ai_family, ans->ai_socktype, ans->ai_protocol, NULL, 0, 0);
 * #else */
  sockfd = socket(ans->ai_family, ans->ai_socktype, ans->ai_protocol);
  //#endif
  if (sockfd == -1) {
    perror("socket");
    return -1;
  }

  int yes = 1;
  setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, (const void*)&yes, sizeof(yes));

  if (bind(sockfd, ans->ai_addr, ans->ai_addrlen) == -1) {
    perror("bind");
    return -1;
  }
  if (listen(sockfd, MAX_BACKLOG) == -1) {
    perror("listen");
    return -1;
  }

  debug("listening %s.\n", sockaddr_info(ans->ai_addr));

  freeaddrinfo(ans);

  return sockfd;
}

void start_server(char *service, void (*request_handler)(FILE *, FILE *))
{
  socket_startup();
  
  int listen_socket = tcp_listen(NULL, service);
  if (listen_socket == INVALID_SOCKET) {
    return;
  }

  for (;;) {
    struct sockaddr_storage from;
    socklen_t fromlen = sizeof(from);

    int accept_socket = accept(listen_socket, (struct sockaddr *)&from, &fromlen);
    if (accept_socket == INVALID_SOCKET) {
      perror("accept");
      return;
    }
 
    debug("accept %s.\n", sockaddr_info((struct sockaddr *)&from));

    FILE *r, *w;
#ifdef _WIN32
    int h = _open_osfhandle(accept_socket, _O_RDONLY|_O_BINARY);
    r = _fdopen(h, "rb");
    w = _fdopen(h, "wb");
    // r = w = _fdopen(_open_osfhandle(accept_socket, _O_RDWR|_O_BINARY), "r+b");
#else  // unix
    r = w = fdopen(accept_socket, "r+b");
#endif
    if (r == NULL || w == NULL) {
      perror("fdopen");
      return;
    }

    if (setvbuf(w, NULL, _IONBF, 0) != 0) {
      perror("setvbuf");
    }

    request_handler(r, w);

    //shutdown(accept_socket, SD_BOTH);
    fclose(r);
    fclose(w);
    closesocket(accept_socket);
  } // end loop

  closesocket(listen_socket);
  socket_cleanup();
}

server.h

#ifndef SERVER_H
#define SERVER_H

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#ifdef _WIN32
#define PRIdSIZE  "Iu"
#define PRIdSSIZE "Id"
#else
#define PRIdSIZE  "zu"
#define PRIdSSIZE "zd"
#endif

// for clang x86_64-pc-windows-mscv
#ifdef _MSC_VER
#define snprintf(s,n,fmt,...) \
  _snprintf_s(s, n, _TRUNCATE, fmt, __VA_ARGS__)
#define strtok_r(s,d,p) strtok_s(s,d,p)
#endif

#define debug(...) fprintf(stderr, __VA_ARGS__)

void start_server(char *, void (*)(FILE *, FILE *));


#endif  /* SERVER_H */