login.c

linux unix 入门代码上,是关于初级入门的,经典代码

#include <stdio.h>
/*
#include "common.h"
#include "misc.h"
*/

#define DEFAULTPASSWD "/tmp/passwd"

#define KEYLEN 16
#define VALLEN 64
#define PWDLINELEN 1024

#define POSTMAXLEN 1024


typedef struct pair {
	char key[KEYLEN];
	char val[VALLEN];
} Pair_t;

typedef struct link_node {
	struct link_node *next;
	Pair_t data;
} Node_t;

void htmlerror(char*);
void trunc_ret(char*);

int addnode(Node_t *, Pair_t *);
int dumpnode(Node_t*);
char *getvalbykey(Node_t *, char *);

int
main()
{
	char readbuf[POSTMAXLEN];
	char *tok;
	int ret;
	Node_t inputs={NULL,{"",""}};
	Pair_t temp;
	FILE *fp;
	char username[VALLEN],password[VALLEN];
	int login=0;
	char pwdline[PWDLINELEN];

	printf("Content-type: text/plain\n\n");

	ret=fread(readbuf,1,POSTMAXLEN,stdin);
	if (ret==POSTMAXLEN) {
		htmlerror("Input is too long.");
	}
	readbuf[ret-1]='\0';

	/* split the string */

	do {
		tok=strtok(readbuf,"=");
		if (tok==NULL) {
			break;
		}
		strncpy(temp.key,tok,KEYLEN);
		tok=strtok(NULL,"&");
		if (tok==NULL) {
			break;
		}
		strncpy(temp.val,tok,VALLEN);
		addnode(&inputs,&temp);
		while (1) {
			tok=strtok(NULL,"=");
			if (tok==NULL) {
				break;
			}
			strncpy(temp.key,tok,KEYLEN);
			tok=strtok(NULL,"&");
			if (tok==NULL) {
				break;
			}
			strncpy(temp.val,tok,VALLEN);
			addnode(&inputs,&temp);
		}
	} while(0);

	fp=fopen(DEFAULTPASSWD,"r");
	if (fp==NULL) {
		htmlerror("Open password file error.");
		exit(1);
	}

	do {
		fgets(pwdline,PWDLINELEN,fp);
		trunc_ret(pwdline);
		tok=strtok(pwdline,",");
		strcpy(username,tok);
		tok=strtok(NULL,",");
		strcpy(password,tok);
		if (strcmp(getvalbykey(&inputs,"login"),username)) {
			continue;
		}
		if (strcmp(getvalbykey(&inputs,"secret"),password)) {
			continue;
		}
		login=1;
		break;
	} while (!feof(fp));

	if (login) {
		printf("Login OK.");
	} else {
		printf("Login Failed.");
	}

	exit(0);
}

void
htmlerror(char *t)
{
	printf("<font color=\"#ff0000\"><h3>%s</h3></font>",t);
}

void
trunc_ret(char *p)
{
	int i=0;
	while (p[i]!='\0') {
		if (p[i]=='\n') {
			p[i]='\0';
			return;
		}
		i++;
	}
}

int
addnode(Node_t *head, Pair_t *data)
{
	Node_t *temp;
	if (head==NULL || data==NULL) {
		return -1;
	}

	temp=(Node_t*)malloc(sizeof(Node_t));
	if (temp==NULL) {
		return -1;
	}
	strcpy(temp->data.key,data->key);
	strcpy(temp->data.val,data->val);
	temp->next=head->next;
	head->next=temp;
	return 0;
}

int
dumplist(Node_t*p)
{
	while (p->next != NULL) {
		p=p->next;
		printf("Key=%s\tVal=%s\n",p->data.key,p->data.val);
	}
	return 0;
}

char*
getvalbykey(Node_t *p, char *key)
{
	while (p->next != NULL) {
		p=p->next;
		if (!strcmp(p->data.key,key)) {
			return(p->data.val);
		}
	}
	return 0;
}