example22.c

LinuxNetProgramming Linux网络编程基础实例

#include	<stdio.h>
#include	<unistd.h>
#include	<dirent.h>
#include	<limits.h>

#define		bufflen		1024
void server(), client();

typedef int pid_t;

int
main(int argc, char **grav)
{
	int	n, pipe1[2], pipe2[2];
	pid_t	childpid;
	
	if (pipe(pipe1) < 0)
		printf("pipe error\n");
	if (pipe(pipe2) < 0)
		printf("pipe error\n");

	if ( (childpid = fork()) < 0)
		exit(0);
	if (childpid > 0) {
		close(pipe1[0]);
		close(pipe2[1]);
		client(pipe2[0], pipe1[1]);
		waitpid(childpid, NULL, 0);
		exit(0);
	}
	else {
		close(pipe1[1]);
		close(pipe2[0]);
		server(pipe1[0], pipe2[1]);
		exit(0);
	}
}

void
server(int readfd, int writefd)
{
	ssize_t 	n;
	char		buff[bufflen], *ptr;
	struct dirent	*dirp;
	DIR		*dp;

	if ((n = read(readfd, buff, bufflen)) == 0)	/*read dirname form IPC channel*/
		exit(0);
	buff[n] = '\0';	/* null terminate */
	ptr = buff + n;
	if ((dp = opendir(buff)) == NULL)
		snprintf(ptr, sizeof(buff) - n, ": not find.\n");	/* tell client error */
	else {
		while ((dirp = readdir(dp)) != NULL) {
			if (strcmp(dirp->d_name, ".") == 0 || 
				strcmp(dirp->d_name, "..") == 0)		/* ignore . and .. directory */
				continue;
			strcpy(ptr, dirp->d_name);		/* copy the filename list to the pipe */
			n = strlen(dirp->d_name);
			ptr += n;
			*ptr = ' ';
			ptr++;
		}
		*ptr = '\0';			/* null terminate */
	}
	n = strlen(buff);
	if ((write(writefd, buff, n)) != n)
		exit(0);
	closedir(dp);
}


void
client(int readfd, int writefd)
{
	size_t	len;
	ssize_t	n;
	char	buff[bufflen];

	fgets(buff, bufflen, stdin);		/* read pathname from the standard input */
	len = strlen(buff);
		/* 删除路径名结尾处的回车符 */
if (buff[len-1] == '\n')
		len--;
	if ((write(writefd, buff, len)) != len)
		exit(0);
		/* 循环从管道中读，直到读到内容为止 */
	while ((n =read(readfd, buff, bufflen)) > 0)
		if ((write(STDOUT_FILENO, buff, n)) != n)
			exit(0);
	printf("\n");
}