Linux终端下简单的登录程序 密码不回显

在Linux进行登录是输入密码不会被回显，所以我也写了个简单的登入程序，使得在输入密码时不再进行回显。

#include <stdio.h>#include <stdlib.h>#include <termios.h>#include <unistd.h>#include <errno.h>#include <string.h>#include <stdbool.h>#define   USER_NAME            "username"#define   USER_PASS            "userpass"#define   MAX                  20#define   ECHOFLAGS           (ECHO | ECHOE | ECHOK)int  set_disp_mode(int fd, int option) {    int  err;    struct termios  term;    if (tcgetattr(fd, &term) == -1) {        fprintf(stderr, "Can\'t get the attribution of the terminal!\n");        exit(1);    }    if (option) {        term.c_lflag |= ECHOFLAGS;    }    else {        term.c_lflag &= ~ECHOFLAGS;    }    err = tcsetattr(fd, TCSAFLUSH, &term);    if (err == -1 && err == EINTR) {        fprintf(stderr, "Can\'t set the attribution of the terminal!\n");        exit(1);    }    return  0;}int  get_passwd(char* passwd, int size) {    int  c;    int  n = 0;    fprintf(stderr, "Please input password:");    do {        c = getchar();        if (c != '\n' && c != '\r') {            passwd[n++] = c;        }    } while (c != '\n' && c != '\r' && n < (size-1));    passwd[n] = '\0';    return n;}bool check_login(const char* name, const char* passwd) {    int nlen = strlen(USER_NAME);    int plen = strlen(USER_PASS);    return  (strncmp(name, USER_NAME, nlen) == 0) &&            (strncmp(passwd, USER_PASS, plen) == 0);}int  main(void) {    char  name[MAX];    char  passwd[MAX];        LOGIN:    fprintf(stderr, "login user:");    fgets(name, MAX, stdin);    name[strlen(name)-1] = '\0';    set_disp_mode(STDIN_FILENO, 0);    get_passwd(passwd, MAX);    if (check_login(name, passwd)) {        fprintf(stderr, "\nHello %s, Welcome!\n", name);    }    else {         fprintf(stderr, "\n");         set_disp_mode(STDIN_FILENO, 1);         goto LOGIN;    }    set_disp_mode(STDIN_FILENO, 1);    return  0;}