fileinout.c

linux平台下的网络通讯程序

#include <stdio.h>
#include <fcntl.h>
#include <string.h>
#include <errno.h>
#include <sys/stat.h>

#define MAX_BUF_SIZE 1024
#define MIN_BUF_SIZE 256

void exit();
typedef struct
{
    char name[MIN_BUF_SIZE];
    char pwd[MIN_BUF_SIZE];
}USRINFO;
int writeinfo(char *fp,const USRINFO *sp)
{
    int fd,bytes_write;
    if((fd=open(fp,O_WRONLY|O_APPEND,S_IRUSR|S_IWUSR))==-1)
    {
	fprintf(stderr,"Open %s Error:%s\n",fp,strerror(errno));
	exit(1);
    }
    bytes_write=write(fd,sp,sizeof(USRINFO));
    close(fd);
    return bytes_write;
}
int readinfo(int fd,USRINFO *sp)
{
    int bytes_read;
    bytes_read=read(fd,sp,sizeof(USRINFO));
    //printf("read ok,name = %s,pwd =%s, size = %d\n",sp->name,sp->pwd,bytes_read);
    return bytes_read;
}
int checkusr(char *fp,const USRINFO *sp)
{
    int fd,bytes_read;
    USRINFO buf;
    if((fd=open(fp,O_RDONLY,S_IRUSR|S_IWUSR))==-1)
    {
	fprintf(stderr,"Open %s Error:%s\n",fp,strerror(errno));
	exit(1);
    }
    while(bytes_read=readinfo(fd,&buf))
    {
	if((bytes_read==-1)&&(errno!=EINTR))break;
	else if(bytes_read>0)
	{
	    if(strcmp(sp->name,buf.name)==0)
	    {
		if(strcmp(sp->pwd,buf.pwd)==0)
		    return 1;
		else
		    return 0;
	    }
	    bzero(&buf,sizeof(USRINFO));
	}
    }
    close(fd);
    return 0;
}
/*
int main(void)
{
    USRINFO buf;
    //printf("name = %s,pwd = %s ,size= %d \n",wenger.name,wenger.pwd,sizeof(USRINFO));
    int fd,i;
    int bytes_read,bytes_write;
    char file1[255]="database";
    /*
    for(i=0;i<3;i++)
    {
	printf("n = :");
	gets(buf.name);
	printf("w = :");
	gets(buf.pwd);
	writeinfo(file1,&buf);
    }
    
    if((fd=open(file1,O_RDONLY,S_IRUSR|S_IWUSR))==-1)
    {
	fprintf(stderr,"Open %s Error:%s\n",file1,strerror(errno));
	exit(1);
    }
    while(bytes_read=readinfo(fd,&buf))
    {
	if((bytes_read==-1)&&(errno!=EINTR))break;
	else if(bytes_read>0)
	{
	    printf("name = %s,pwd = %s \n",buf.name,buf.pwd);
	    bzero(&buf,sizeof(USRINFO));
	}
    }
    close(fd);
    printf("UID = :");
    gets(buf.name);
    printf("PWD = :");
    gets(buf.pwd);
    int a;
    if((a=checkusr(file1,&buf))==1)
	printf("login\n");
    else
	printf("unvalid usr\n");
    return 0;
}
*/