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/* -*- coding: utf-8 -*- */
/*
* Passprompt - Read a password from the terminal and print it
*
* Copyright © 2007-2008 Teddy Hogeborn and Björn Påhlsson.
*
* This program is free software: you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation, either version 3 of the
* License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see
* <http://www.gnu.org/licenses/>.
*
* Contact the authors at <https://www.fukt.bsnet.se/~belorn/> and
* <https://www.fukt.bsnet.se/~teddy/>.
*/
#define _GNU_SOURCE /* getline() */
#define _FORTIFY_SOURCE 2
#include <termios.h> /* struct termios, tcsetattr(),
TCSAFLUSH, tcgetattr(), ECHO */
#include <unistd.h> /* struct termios, tcsetattr(),
STDIN_FILENO, TCSAFLUSH,
tcgetattr(), ECHO */
#include <signal.h> /* sig_atomic_t, raise(), struct
sigaction, sigemptyset(),
sigaction(), sigaddset(), SIGINT,
SIGQUIT, SIGHUP, SIGTERM */
#include <stddef.h> /* NULL, size_t */
#include <sys/types.h> /* ssize_t */
#include <stdlib.h> /* EXIT_SUCCESS, EXIT_FAILURE,
getopt_long */
#include <stdio.h> /* fprintf(), stderr, getline(),
stdin, feof(), perror(), fputc(),
stdout, getopt_long */
#include <errno.h> /* errno, EINVAL */
#include <iso646.h> /* or, not */
#include <stdbool.h> /* bool, false, true */
#include <string.h> /* strlen, rindex, strncmp, strcmp */
#include <getopt.h> /* getopt_long */
volatile bool quit_now = false;
bool debug = false;
void termination_handler(__attribute__((unused))int signum){
quit_now = true;
}
int main(int argc, char **argv){
ssize_t ret;
size_t n;
struct termios t_new, t_old;
char *buffer = NULL;
char *prefix = NULL;
int status = EXIT_SUCCESS;
struct sigaction old_action,
new_action = { .sa_handler = termination_handler,
.sa_flags = 0 };
while (true){
static struct option long_options[] = {
{"debug", no_argument, (int *)&debug, 1},
{"prefix", required_argument, 0, 'p'},
{0, 0, 0, 0} };
int option_index = 0;
ret = getopt_long (argc, argv, "p:", long_options, &option_index);
if (ret == -1){
break;
}
switch(ret){
case 0:
break;
case 'p':
prefix = optarg;
break;
default:
fprintf(stderr, "bad arguments\n");
exit(EXIT_FAILURE);
}
}
if (debug){
fprintf(stderr, "Starting %s\n", argv[0]);
}
if (debug){
fprintf(stderr, "Storing current terminal attributes\n");
}
if (tcgetattr(STDIN_FILENO, &t_old) != 0){
return EXIT_FAILURE;
}
sigemptyset(&new_action.sa_mask);
sigaddset(&new_action.sa_mask, SIGINT);
sigaddset(&new_action.sa_mask, SIGQUIT);
sigaddset(&new_action.sa_mask, SIGHUP);
sigaddset(&new_action.sa_mask, SIGTERM);
sigaction(SIGINT, NULL, &old_action);
if (old_action.sa_handler != SIG_IGN)
sigaction(SIGINT, &new_action, NULL);
sigaction(SIGQUIT, NULL, &old_action);
if (old_action.sa_handler != SIG_IGN)
sigaction(SIGQUIT, &new_action, NULL);
sigaction(SIGHUP, NULL, &old_action);
if (old_action.sa_handler != SIG_IGN)
sigaction(SIGHUP, &new_action, NULL);
sigaction(SIGTERM, NULL, &old_action);
if (old_action.sa_handler != SIG_IGN)
sigaction(SIGTERM, &new_action, NULL);
if (debug){
fprintf(stderr, "Removing echo flag from terminal attributes\n");
}
t_new = t_old;
t_new.c_lflag &= ~ECHO;
if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &t_new) != 0){
perror("tcsetattr-echo");
return EXIT_FAILURE;
}
if (debug){
fprintf(stderr, "Waiting for input from stdin \n");
}
while(true){
if (quit_now){
status = EXIT_FAILURE;
break;
}
if(prefix){
fprintf(stderr, "%s Password: ", prefix);
} else {
fprintf(stderr, "Password: ");
}
ret = getline(&buffer, &n, stdin);
if (ret > 0){
fprintf(stdout, "%s", buffer);
status = EXIT_SUCCESS;
break;
}
// ret == 0 makes no other sence than to retry to read from stdin
if (ret < 0){
if (errno != EINTR and not feof(stdin)){
perror("getline");
status = EXIT_FAILURE;
break;
}
}
fputc('\n', stderr);
}
if (debug){
fprintf(stderr, "Restoring terminal attributes\n");
}
if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &t_old) != 0){
perror("tcsetattr+echo");
}
if (debug){
fprintf(stderr, "%s is exiting\n", argv[0]);
}
return status;
}
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