unix下取得加密的用户密码

在ubuntu中写一个比较密码的程序:

#define _XOPEN_SOURCE
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <shadow.h>
#include <pwd.h>

int main(int argc,char **argv)
{
	if(argc!=2){
		printf("usage : %s user_namen",argv[0]);
		exit(-1);
	}
	
	struct passwd *pwd = getpwnam(argv[1]);
	printf("%s pwd is %sn",argv[1],pwd->pw_passwd);
	
	struct spwd *spwd = getspnam(argv[1]);
	printf("%s pwd is %sn",argv[1],spwd->sp_pwdp);
	
	char *pwd_in = getpass("passwd:");
	char *epwd = crypt(pwd_in,spwd->sp_pwdp);
	printf("%s epwd is %sn",argv[1],epwd);
	
	return 0;
}