多进程服务器

主程序：

#include "wrap.h"
#include <signal.h>
#include <sys/wait.h>
//多进程服务器

void communicate(int client_fd, char *IP)
{
    char buf[1024];
    while (1)
    {
        printf("发给%s：", IP);
        fflush(stdout);
        bzero(buf, 1024);
        Read(STDIN_FILENO, buf, 1024);
        Write(client_fd, buf, 1024);
        printf("从%s收：", IP);
        fflush(stdout);
        bzero(buf, 1024);
        int n = Read(client_fd, buf, 1024);
        printf("%d:%s\n",n, buf);
        if(0 == n)
            break;
    }
    
}

void free_process(int sig)
{
    printf("回收\n");
    while(1)
    {
        int ret = waitpid(-1, NULL, WNOHANG);
        if(ret <= 0)
            break;
        else
            printf("child id:%d\n", ret);
    }
}

int main() {
    //套接字
    int fd = Socket(AF_INET, SOCK_STREAM, 0);
    char buf[1024] = "";
    //bind
    struct sockaddr_in s_addr, c_addr;
    int len = sizeof(s_addr);
    s_addr.sin_family = AF_INET;
    s_addr.sin_port = htons(8000);
    inet_pton(AF_INET, "192.168.68.152", &s_addr.sin_addr.s_addr);
    Bind(fd, (struct sockaddr*)&s_addr, len);
    
    
    //阻塞SIG_CHLD,看84行
    sigset_t block_chld;
    sigemptyset(&block_chld);
    sigaddset(&block_chld, SIGCHLD);
    sigprocmask(SIG_BLOCK, &block_chld, NULL);
    Listen(fd, 128);

    while (1)
    {
        int client_fd = Accept(fd, (struct sockaddr*)&c_addr, &len);

        bzero(buf, 1024);
        printf("%s已连接\n", inet_ntop(AF_INET, &c_addr.sin_addr.s_addr, buf, 1024));

        //子进程
        if(0 == fork()) 
        {
            Close(fd);
            communicate(client_fd, buf);
            return 0;
        }
        // 父进程
        else  
        {
            Close(client_fd);

            struct sigaction act;
            act.sa_flags = 0;
            act.sa_handler = free_process;
            sigemptyset(&act.sa_mask);
            sigaction(SIGCLD, &act, NULL);
            //把阻塞的SIGCHLD放出来
            sigprocmask(SIG_UNBLOCK,&block_chld,NULL);
        }
    }
    
    return 0;
}

头文件：

#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <strings.h>

void perr_exit(const char *s)
{
	perror(s);
	exit(-1);
}

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

again:
	if ((n = accept(fd, sa, salenptr)) < 0) {
		if ((errno == ECONNABORTED) || (errno == EINTR))//如果是被信号中断和软件层次中断,不能退出
			goto again;
		else
			perr_exit("accept error");
	}
	return n;
}

int Bind(int fd, const struct sockaddr *sa, socklen_t salen)
{
    int n;

	if ((n = bind(fd, sa, salen)) < 0)
		perr_exit("bind error");

    return n;
}

int Connect(int fd, const struct sockaddr *sa, socklen_t salen)
{
    int n;

	if ((n = connect(fd, sa, salen)) < 0)
		perr_exit("connect error");

    return n;
}

int Listen(int fd, int backlog)
{
    int n;

	if ((n = listen(fd, backlog)) < 0)
		perr_exit("listen error");

    return n;
}

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

	if ((n = socket(family, type, protocol)) < 0)
		perr_exit("socket error");

	return n;
}

ssize_t Read(int fd, void *ptr, size_t nbytes)
{
	ssize_t n;

again:
	if ( (n = read(fd, ptr, nbytes)) == -1) {
		if (errno == EINTR)//如果是被信号中断,不应该退出
			goto again;
		else
			return -1;
	}
	return n;
}

ssize_t Write(int fd, const void *ptr, size_t nbytes)
{
	ssize_t n;

again:
	if ( (n = write(fd, ptr, nbytes)) == -1) {
		if (errno == EINTR)
			goto again;
		else
			return -1;
	}
	return n;
}

int Close(int fd)
{
    int n;
	if ((n = close(fd)) == -1)
		perr_exit("close error");

    return n;
}

/*参三: 应该读取固定的字节数数据*/
ssize_t Readn(int fd, void *vptr, size_t n)
{
	size_t  nleft;              //usigned int 剩余未读取的字节数
	ssize_t nread;              //int 实际读到的字节数
	char   *ptr;

	ptr = vptr;
	nleft = n;

	while (nleft > 0) {
		if ((nread = read(fd, ptr, nleft)) < 0) {
			if (errno == EINTR)
				nread = 0;
			else
				return -1;
		} else if (nread == 0)
			break;

		nleft -= nread;
		ptr += nread;
	}
	return n - nleft;
}
/*:固定的字节数数据*/
ssize_t Writen(int fd, const void *vptr, size_t n)
{
	size_t nleft;
	ssize_t nwritten;
	const char *ptr;

	ptr = vptr;
	nleft = n;
	while (nleft > 0) {
		if ( (nwritten = write(fd, ptr, nleft)) <= 0) {
			if (nwritten < 0 && errno == EINTR)
				nwritten = 0;
			else
				return -1;
		}

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

static ssize_t my_read(int fd, char *ptr)
{
	static int read_cnt;
	static char *read_ptr;
	static char read_buf[100];

	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, size_t maxlen)
{
	ssize_t n, rc;
	char    c, *ptr;

	ptr = vptr;
	for (n = 1; n < maxlen; n++) {
		if ( (rc = my_read(fd, &c)) == 1) {
			*ptr++ = c;
			if (c  == '\n')
				break;
		} else if (rc == 0) {
			*ptr = 0;
			return n - 1;
		} else
			return -1;
	}
	*ptr  = 0;

	return n;
}

int tcp4bind(short port,const char *IP)
{
    struct sockaddr_in serv_addr;
    int lfd = Socket(AF_INET,SOCK_STREAM,0);
    bzero(&serv_addr,sizeof(serv_addr));
    if(IP == NULL){
        //如果这样使用 0.0.0.0,任意ip将可以连接
        serv_addr.sin_addr.s_addr = INADDR_ANY;
    }else{
        if(inet_pton(AF_INET,IP,&serv_addr.sin_addr.s_addr) <= 0){
            perror(IP);//转换失败
            exit(1);
        }
    }
    serv_addr.sin_family = AF_INET;
    serv_addr.sin_port   = htons(port);
   // int opt = 1;
	//setsockopt(lfd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt));

    Bind(lfd,(struct sockaddr *)&serv_addr,sizeof(serv_addr));
    return lfd;
}