1/* vi: set sw=4 ts=4: */
2/*
3 * Ask for a password
4 * I use a static buffer in this function.  Plan accordingly.
5 *
6 * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
7 *
8 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
9 */
10
11#include <termios.h>
12
13#include "libbb.h"
14
15/* do nothing signal handler */
16static void askpass_timeout(int ATTRIBUTE_UNUSED ignore)
17{
18}
19
20char *bb_askpass(int timeout, const char * prompt)
21{
22	/* Was static char[BIGNUM] */
23	enum { sizeof_passwd = 128 };
24	static char *passwd;
25
26	char *ret;
27	int i;
28	struct sigaction sa;
29	struct termios old, new;
30
31	if (!passwd)
32		passwd = xmalloc(sizeof_passwd);
33	memset(passwd, 0, sizeof_passwd);
34
35	tcgetattr(STDIN_FILENO, &old);
36	tcflush(STDIN_FILENO, TCIFLUSH);
37
38	fputs(prompt, stdout);
39	fflush(stdout);
40
41	tcgetattr(STDIN_FILENO, &new);
42	new.c_iflag &= ~(IUCLC|IXON|IXOFF|IXANY);
43	new.c_lflag &= ~(ECHO|ECHOE|ECHOK|ECHONL|TOSTOP);
44	tcsetattr(STDIN_FILENO, TCSANOW, &new);
45
46	if (timeout) {
47		sa.sa_flags = 0;
48		sa.sa_handler = askpass_timeout;
49		sigaction(SIGALRM, &sa, NULL);
50		alarm(timeout);
51	}
52
53	ret = NULL;
54	/* On timeout, read will hopefully be interrupted by SIGALRM,
55	 * and we return NULL */
56	if (read(STDIN_FILENO, passwd, sizeof_passwd-1) > 0) {
57		ret = passwd;
58		i = 0;
59		/* Last byte is guaranteed to be 0
60		   (read did not overwrite it) */
61		do {
62			if (passwd[i] == '\r' || passwd[i] == '\n')
63				passwd[i] = '\0';
64		} while (passwd[i++]);
65	}
66
67	if (timeout) {
68		alarm(0);
69	}
70
71	tcsetattr(STDIN_FILENO, TCSANOW, &old);
72	putchar('\n');
73	fflush(stdout);
74	return ret;
75}
76