#include <stdio.h>
#include <termios.h>

static struct termios stored_settings;
static void set_keypress(void)
{
    struct termios new_settings;

        //存储旧的模式
    tcgetattr(0,&stored_settings);
    
    new_settings = stored_settings;

    /* Disable canonical mode, and set buffer size to 1 byte */
    new_settings.c_lflag &= (~ICANON);    // 不使用标准模式，即取消行缓冲
    new_settings.c_cc[VTIME] = 0;
    new_settings.c_cc[VMIN] = 1;
    new_settings.c_lflag &= ~ECHO;
    
    tcsetattr(0, TCSANOW, &new_settings);
    return;
}
static void reset_keypress(void)
{
    tcsetattr(0,TCSANOW,&stored_settings); // 恢复旧模式
    return;
}

/** readpasswd */
void readpasswd( char* buffer, int size)
{
    char c;
    int cnt = 0;        
    set_keypress();
    while ((c = getchar()) != ‘\n‘) {
        putchar(‘*‘);
        buffer[cnt++] = c;
        if (cnt >= size-1)
            break;
    }
    reset_keypress();
    buffer[cnt] = 0;    
}

int main(int argc, char* argv[])
{
    char buffer[100];
    readpasswd(buffer, 100);
    printf("input password:%s\n", buffer);    
}

输入密码串回显*号