1 /* vi: set sw=4 ts=4: */
2 /*
3 * Ask for a password
4 *
5 * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
6 *
7 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
8 */
9 #include "libbb.h"
10
11 /* do nothing signal handler */
askpass_timeout(int UNUSED_PARAM ignore)12 static void askpass_timeout(int UNUSED_PARAM ignore)
13 {
14 }
15
bb_ask_noecho(int fd,int timeout,const char * prompt)16 char* FAST_FUNC bb_ask_noecho(int fd, int timeout, const char *prompt)
17 {
18 #define MAX_LINE 0xfff
19 char *ret;
20 int i;
21 struct sigaction sa, oldsa;
22 struct termios tio, oldtio;
23
24 tcflush(fd, TCIFLUSH);
25 /* Was buggy: was printing prompt *before* flushing input,
26 * which was upsetting "expect" based scripts of some users.
27 */
28 fputs_stdout(prompt);
29 fflush_all();
30
31 tcgetattr(fd, &oldtio);
32 tio = oldtio;
33 /* Switch off echo. ECHOxyz meaning:
34 * ECHO echo input chars
35 * ECHOE echo BS-SP-BS on erase character
36 * ECHOK echo kill char specially, not as ^c (ECHOKE controls how exactly)
37 * ECHOKE erase all input via BS-SP-BS on kill char (else go to next line)
38 * ECHOCTL Echo ctrl chars as ^c (else echo verbatim:
39 * e.g. up arrow emits "ESC-something" and thus moves cursor up!)
40 * ECHONL Echo NL even if ECHO is not set
41 * ECHOPRT On erase, echo erased chars
42 * [qwe<BS><BS><BS> input looks like "qwe\ewq/" on screen]
43 */
44 tio.c_lflag &= ~(ECHO|ECHOE|ECHOK|ECHONL);
45 tcsetattr(fd, TCSANOW, &tio);
46
47 memset(&sa, 0, sizeof(sa));
48 /* sa.sa_flags = 0; - no SA_RESTART! */
49 /* SIGINT and SIGALRM will interrupt reads below */
50 sa.sa_handler = askpass_timeout;
51 sigaction(SIGINT, &sa, &oldsa);
52 if (timeout) {
53 sigaction_set(SIGALRM, &sa);
54 alarm(timeout);
55 }
56
57 ret = NULL;
58 i = 0;
59 while (1) {
60 int r;
61
62 /* User input is uber-slow, no need to optimize reallocs.
63 * Grow it on every char.
64 */
65 ret = xrealloc(ret, i + 2);
66 r = read(fd, &ret[i], 1);
67
68 if ((i == 0 && r == 0) /* EOF (^D) with no password */
69 || r < 0 /* read is interrupted by timeout or ^C */
70 ) {
71 ret[i] = '\0'; /* paranoia */
72 nuke_str(ret); /* paranoia */
73 free(ret);
74 ret = NULL;
75 break;
76 }
77
78 if (r == 0 /* EOF */
79 || ret[i] == '\r' || ret[i] == '\n' /* EOL */
80 || ++i == MAX_LINE /* line limit */
81 ) {
82 ret[i] = '\0';
83 break;
84 }
85 }
86
87 if (timeout) {
88 alarm(0);
89 }
90 sigaction_set(SIGINT, &oldsa);
91 tcsetattr(fd, TCSANOW, &oldtio);
92 bb_putchar('\n');
93 fflush_all();
94 return ret;
95 }
bb_ask_noecho_stdin(const char * prompt)96 char* FAST_FUNC bb_ask_noecho_stdin(const char *prompt)
97 {
98 return bb_ask_noecho(STDIN_FILENO, 0, prompt);
99 }
100