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Unix网络编程代码 第5章 TCP客户/服务器程序示例

2013年10月04日 ⁄ 综合 ⁄ 共 10817字 ⁄ 字号 小 中 大 ⁄ 评论关闭

第3章 套接字编程简介

3.4 字节排序函数

#include <stdio.h>
#include <stdlib.h>
#define CPU_VENDOR_OS "i686-pc-linux-gnu"
int main(int argc, char **argv)
{
	union {
		short  s;
		char   c[sizeof(short)];
	} un;

	un.s = 0x0102;
	printf("%s: ", CPU_VENDOR_OS);
	if (sizeof(short) == 2) {
		if (un.c[0] == 1 && un.c[1] == 2)
			printf("big-endian\n");
		else if (un.c[0] == 2 && un.c[1] == 1)
			printf("little-endian\n");
		else
			printf("unknown\n");
	} else
		printf("sizeof(short) = %d\n", sizeof(short));

	exit(0);
}

第5章 TCP客户/服务器程序示例

5.2 TCP回射服务器程序

#include	<strings.h>
#include	<sys/types.h>	/* basic system data types */
#include	<sys/socket.h>	/* basic socket definitions */
#include	<netinet/in.h>	/* sockaddr_in{} and other Internet defns */
#include	<stdarg.h>	/* ANSI C header file */
#include	<syslog.h>	/* for syslog() */
#include	<errno.h>
#include	<stdio.h>
#include	<string.h>
#include	<unistd.h>
#include	<stdlib.h>
int daemon_proc;		/* set nonzero by daemon_init() */
#define	SA	struct sockaddr
#define	MAXLINE		4096	/* max text line length */
#define	SERV_PORT		 9877	/* TCP and UDP */
#define	LISTENQ		1024	/* 2nd argument to listen() */
void err_doit(int errnoflag, int level, const char *fmt, va_list ap)
{
	int errno_save, n;
	char buf[MAXLINE + 1];

	errno_save = errno;	/* value caller might want printed */
#ifdef	HAVE_VSNPRINTF
	vsnprintf(buf, MAXLINE, fmt, ap);	/* safe */
#else
	vsprintf(buf, fmt, ap);	/* not safe */
#endif
	n = strlen(buf);
	if (errnoflag)
		snprintf(buf + n, MAXLINE - n, ": %s", strerror(errno_save));
	strcat(buf, "\n");

	if (daemon_proc) {
		syslog(level, "%s",buf);
	} else {
		fflush(stdout);	/* in case stdout and stderr are the same */
		fputs(buf, stderr);
		fflush(stderr);
	}
	return;
}

void err_sys(const char *fmt, ...)
{
	va_list ap;

	va_start(ap, fmt);
	err_doit(1, LOG_ERR, fmt, ap);
	va_end(ap);
	exit(1);
}

int Socket(int family, int type, int protocol)
{
	int n;

	if ((n = socket(family, type, protocol)) < 0)
		err_sys("socket error");
	return (n);
}

void Bind(int fd, const struct sockaddr *sa, socklen_t salen)
{
	if (bind(fd, sa, salen) < 0)
		err_sys("bind error");
}

void Listen(int fd, int backlog)
{
	char *ptr;

	/*4can override 2nd argument with environment variable */
	if ((ptr = getenv("LISTENQ")) != NULL)
		backlog = atoi(ptr);

	if (listen(fd, backlog) < 0)
		err_sys("listen error");
}

int Accept(int fd, struct sockaddr *sa, socklen_t * salenptr)
{
	int n;

 again:
	if ((n = accept(fd, sa, salenptr)) < 0) {
#ifdef	EPROTO
		if (errno == EPROTO || errno == ECONNABORTED)
#else
		if (errno == ECONNABORTED)
#endif
			goto again;
		else
			err_sys("accept error");
	}
	return (n);
}

pid_t Fork(void)
{
	pid_t pid;

	if ((pid = fork()) == -1)
		err_sys("fork error");
	return (pid);
}

void Close(int fd)
{
	if (close(fd) == -1)
		err_sys("close error");
}

ssize_t				/* Write "n" bytes to a descriptor. */
writen(int fd, const void *vptr, size_t n)
{
	size_t nleft;
	ssize_t nwritten;
	const char *ptr;

	ptr = (const char *)vptr;
	nleft = n;
	while (nleft > 0) {
		if ((nwritten = write(fd, ptr, nleft)) <= 0) {
			if (nwritten < 0 && errno == EINTR)
				nwritten = 0;	/* and call write() again */
			else
				return (-1);	/* error */
		}

		nleft -= nwritten;
		ptr += nwritten;
	}
	return (n);
}

void Writen(int fd, void *ptr, int nbytes)
{
	if (writen(fd, ptr, nbytes) != nbytes)
		err_sys("writen error");
}

void str_echo(int sockfd)
{
	ssize_t n;
	char buf[MAXLINE];

 again:
	while ((n = read(sockfd, buf, MAXLINE)) > 0)
		Writen(sockfd, buf, n);

	if (n < 0 && errno == EINTR)
		goto again;
	else if (n < 0)
		err_sys("str_echo: read error");
}

int main()
{
	int listenfd, connfd;
	pid_t childpid;
	socklen_t clilen;
	struct sockaddr_in cliaddr, servaddr;

	listenfd = Socket(AF_INET, SOCK_STREAM, 0);

	bzero(&servaddr, sizeof(servaddr));
	servaddr.sin_family = AF_INET;
	servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
	servaddr.sin_port = htons(SERV_PORT);

	Bind(listenfd, (SA *) & servaddr, sizeof(servaddr));

	Listen(listenfd, LISTENQ);

	for (;;) {
		clilen = sizeof(cliaddr);
		connfd = Accept(listenfd, (SA *) & cliaddr, &clilen);

		if ((childpid = Fork()) == 0) {	/* child process */
			Close(listenfd);	/* close listening socket */
			str_echo(connfd);	/* process the request */
			exit(0);
		}
		Close(connfd);	/* parent closes connected socket */
	}
}

5.4 TCP回射客户程序

#include	<netinet/in.h>	/* sockaddr_in{} and other Internet defns */
#include	<strings.h>
#include	<stdarg.h>	/* ANSI C header file */
#include	<syslog.h>	/* for syslog() */
#include	<errno.h>
#include	<string.h>
#include	<stdio.h>
#include	<stdlib.h>
#include	<arpa/inet.h>
#include	<unistd.h>
#define	MAXLINE		4096	/* max text line length */
#define	SERV_PORT		 9877	/* TCP and UDP */
int daemon_proc;		/* set nonzero by daemon_init() */
#define	SA	struct sockaddr
void err_doit(int errnoflag, int level, const char *fmt, va_list ap)
{
	int errno_save, n;
	char buf[MAXLINE + 1];

	errno_save = errno;	/* value caller might want printed */
#ifdef	HAVE_VSNPRINTF
	vsnprintf(buf, MAXLINE, fmt, ap);	/* safe */
#else
	vsprintf(buf, fmt, ap);	/* not safe */
#endif
	n = strlen(buf);
	if (errnoflag)
		snprintf(buf + n, MAXLINE - n, ": %s", strerror(errno_save));
	strcat(buf, "\n");

	if (daemon_proc) {
		syslog(level, "%s",buf);
	} else {
		fflush(stdout);	/* in case stdout and stderr are the same */
		fputs(buf, stderr);
		fflush(stderr);
	}
	return;
}

void err_quit(const char *fmt, ...)
{
	va_list ap;

	va_start(ap, fmt);
	err_doit(0, LOG_ERR, fmt, ap);
	va_end(ap);
	exit(1);
}

void err_sys(const char *fmt, ...)
{
	va_list ap;

	va_start(ap, fmt);
	err_doit(1, LOG_ERR, fmt, ap);
	va_end(ap);
	exit(1);
}

int Socket(int family, int type, int protocol)
{
	int n;

	if ((n = socket(family, type, protocol)) < 0)
		err_sys("socket error");
	return (n);
}

void Inet_pton(int family, const char *strptr, void *addrptr)
{
	int n;

	if ((n = inet_pton(family, strptr, addrptr)) < 0)
		err_sys("inet_pton error for %s", strptr);	/* errno set */
	else if (n == 0)
		err_quit("inet_pton error for %s", strptr);	/* errno not set */

	/* nothing to return */
}

void Connect(int fd, const struct sockaddr *sa, socklen_t salen)
{
	if (connect(fd, sa, salen) < 0)
		err_sys("connect error");
}

ssize_t writen(int fd, const void *vptr, size_t n)
{
	size_t nleft;
	ssize_t nwritten;
	const char *ptr;

	ptr = (const char *)vptr;
	nleft = n;
	while (nleft > 0) {
		if ((nwritten = write(fd, ptr, nleft)) <= 0) {
			if (nwritten < 0 && errno == EINTR)
				nwritten = 0;	/* and call write() again */
			else
				return (-1);	/* error */
		}

		nleft -= nwritten;
		ptr += nwritten;
	}
	return (n);
}

void Writen(int fd, void *ptr, int nbytes)
{
	if (writen(fd, ptr, nbytes) != nbytes)
		err_sys("writen error");
}

char *Fgets(char *ptr, int n, FILE * stream)
{
	char *rptr;

	if ((rptr = fgets(ptr, n, stream)) == NULL && ferror(stream))
		err_sys("fgets error");

	return (rptr);
}

void Fputs(const char *ptr, FILE * stream)
{
	if (fputs(ptr, stream) == EOF)
		err_sys("fputs error");
}

static int read_cnt;
static char *read_ptr;
static char read_buf[MAXLINE];
static ssize_t my_read(int fd, char *ptr)
{

	if (read_cnt <= 0) {
 again:
		if ((read_cnt = read(fd, read_buf, sizeof(read_buf))) < 0) {
			if (errno == EINTR)
				goto again;
			return (-1);
		} else if (read_cnt == 0)
			return (0);
		read_ptr = read_buf;
	}

	read_cnt--;
	*ptr = *read_ptr++;
	return (1);
}

ssize_t readline(int fd, void *vptr, int maxlen)
{
	ssize_t n, rc;
	char c, *ptr;

	ptr = (char *)vptr;
	for (n = 1; n < maxlen; n++) {
		if ((rc = my_read(fd, &c)) == 1) {
			*ptr++ = c;
			if (c == '\n')
				break;	/* newline is stored, like fgets() */
		} else if (rc == 0) {
			*ptr = 0;
			return (n - 1);	/* EOF, n - 1 bytes were read */
		} else
			return (-1);	/* error, errno set by read() */
	}

	*ptr = 0;		/* null terminate like fgets() */
	return (n);
}

ssize_t Readline(int fd, void *ptr, size_t maxlen)
{
	ssize_t n;

	if ((n = readline(fd, ptr, maxlen)) < 0)
		err_sys("readline error");
	return (n);
}

void str_cli(FILE * fp, int sockfd)
{
	char sendline[MAXLINE], recvline[MAXLINE];

	while (Fgets(sendline, MAXLINE, fp) != NULL) {

		Writen(sockfd, sendline, strlen(sendline));

		if (Readline(sockfd, recvline, MAXLINE) == 0)
			err_quit("str_cli: server terminated prematurely");

		Fputs(recvline, stdout);
	}
}

int main(int argc, char **argv)
{
	int sockfd;
	struct sockaddr_in servaddr;

	if (argc != 2)
		err_quit("usage: tcpcli <IPaddress>");

	sockfd = Socket(AF_INET, SOCK_STREAM, 0);

	bzero(&servaddr, sizeof(servaddr));
	servaddr.sin_family = AF_INET;
	servaddr.sin_port = htons(SERV_PORT);
	Inet_pton(AF_INET, argv[1], &servaddr.sin_addr);

	Connect(sockfd, (SA *) & servaddr, sizeof(servaddr));

	str_cli(stdin, sockfd);	/* do it all */

	exit(0);
}

5.10 wait和waitpid函数

//带上信号处理函数的server
#define _POSIX_SOURCE
#include	<strings.h>
#include	<signal.h>
#include	<sys/types.h>	/* basic system data types */
#include	<sys/socket.h>	/* basic socket definitions */
#include	<netinet/in.h>	/* sockaddr_in{} and other Internet defns */
#include	<stdarg.h>	/* ANSI C header file */
#include	<syslog.h>	/* for syslog() */
#include	<errno.h>
#include	<stdio.h>
#include	<string.h>
#include	<unistd.h>
#include	<stdlib.h>
#include	<sys/wait.h>
int daemon_proc;		/* set nonzero by daemon_init() */
#define	SA	struct sockaddr
#define	MAXLINE		4096	/* max text line length */
#define	SERV_PORT		 9877	/* TCP and UDP */
#define	LISTENQ		1024	/* 2nd argument to listen() */
typedef void Sigfunc(int);	/* for signal handlers */
void err_doit(int errnoflag, int level, const char *fmt, va_list ap)
{
	int errno_save, n;
	char buf[MAXLINE + 1];

	errno_save = errno;	/* value caller might want printed */
#ifdef	HAVE_VSNPRINTF
	vsnprintf(buf, MAXLINE, fmt, ap);	/* safe */
#else
	vsprintf(buf, fmt, ap);	/* not safe */
#endif
	n = strlen(buf);
	if (errnoflag)
		snprintf(buf + n, MAXLINE - n, ": %s", strerror(errno_save));
	strcat(buf, "\n");

	if (daemon_proc) {
		syslog(level, "%s", buf);
	} else {
		fflush(stdout);	/* in case stdout and stderr are the same */
		fputs(buf, stderr);
		fflush(stderr);
	}
	return;
}

void err_sys(const char *fmt, ...)
{
	va_list ap;

	va_start(ap, fmt);
	err_doit(1, LOG_ERR, fmt, ap);
	va_end(ap);
	exit(1);
}

int Socket(int family, int type, int protocol)
{
	int n;

	if ((n = socket(family, type, protocol)) < 0)
		err_sys("socket error");
	return (n);
}

void Bind(int fd, const struct sockaddr *sa, socklen_t salen)
{
	if (bind(fd, sa, salen) < 0)
		err_sys("bind error");
}

void Listen(int fd, int backlog)
{
	char *ptr;

	/*4can override 2nd argument with environment variable */
	if ((ptr = getenv("LISTENQ")) != NULL)
		backlog = atoi(ptr);

	if (listen(fd, backlog) < 0)
		err_sys("listen error");
}

pid_t Fork(void)
{
	pid_t pid;

	if ((pid = fork()) == -1)
		err_sys("fork error");
	return (pid);
}

void Close(int fd)
{
	if (close(fd) == -1)
		err_sys("close error");
}

ssize_t				/* Write "n" bytes to a descriptor. */
writen(int fd, const void *vptr, size_t n)
{
	size_t nleft;
	ssize_t nwritten;
	const char *ptr;

	ptr = (const char *)vptr;
	nleft = n;
	while (nleft > 0) {
		if ((nwritten = write(fd, ptr, nleft)) <= 0) {
			if (nwritten < 0 && errno == EINTR)
				nwritten = 0;	/* and call write() again */
			else
				return (-1);	/* error */
		}

		nleft -= nwritten;
		ptr += nwritten;
	}
	return (n);
}

void Writen(int fd, void *ptr, int nbytes)
{
	if (writen(fd, ptr, nbytes) != nbytes)
		err_sys("writen error");
}

void str_echo(int sockfd)
{
	ssize_t n;
	char buf[MAXLINE];

 again:
	while ((n = read(sockfd, buf, MAXLINE)) > 0)
		Writen(sockfd, buf, n);

	if (n < 0 && errno == EINTR)
		goto again;
	else if (n < 0)
		err_sys("str_echo: read error");
}

void sig_chld(int signo)
{
	pid_t pid;
	int stat;

	while ((pid = waitpid(-1, &stat, WNOHANG)) > 0)
		printf("child %d terminated\n", pid);
	return;
}

Sigfunc *signal(int signo, Sigfunc * func)
{
	struct sigaction act, oact;

	act.sa_handler = func;
	sigemptyset(&act.sa_mask);
	act.sa_flags = 0;
	if (signo == SIGALRM) {
#ifdef	SA_INTERRUPT
		act.sa_flags |= SA_INTERRUPT;	/* SunOS 4.x */
#endif
	} else {
#ifdef	SA_RESTART
		act.sa_flags |= SA_RESTART;	/* SVR4, 44BSD */
#endif
	}
	if (sigaction(signo, &act, &oact) < 0)
		return (SIG_ERR);
	return (oact.sa_handler);
}

Sigfunc *Signal(int signo, Sigfunc * func)
{				/* for our signal() function */
	Sigfunc *sigfunc;

	if ((sigfunc = signal(signo, func)) == SIG_ERR)
		err_sys("signal error");
	return (sigfunc);
}

int main()
{
	int listenfd, connfd;
	pid_t childpid;
	socklen_t clilen;
	struct sockaddr_in cliaddr, servaddr;

	listenfd = Socket(AF_INET, SOCK_STREAM, 0);

	bzero(&servaddr, sizeof(servaddr));
	servaddr.sin_family = AF_INET;
	servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
	servaddr.sin_port = htons(SERV_PORT);

	Bind(listenfd, (SA *) & servaddr, sizeof(servaddr));

	Listen(listenfd, LISTENQ);

	Signal(SIGCHLD, sig_chld);	/* must call waitpid() */

	for (;;) {
		clilen = sizeof(cliaddr);
		if ((connfd = accept(listenfd, (SA *) & cliaddr, &clilen)) < 0) {
			if (errno == EINTR)
				continue;	/* back to for() */
			else
				err_sys("accept error");
		}

		if ((childpid = Fork()) == 0) {	/* child process */
			Close(listenfd);	/* close listening socket */
			str_echo(connfd);	/* process the request */
			exit(0);
		}
		Close(connfd);	/* parent closes connected socket */
	}
}
















														

							

			

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