busybox/libbb/bb_askpass.c

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/* vi: set sw=4 ts=4: */
/*
* Ask for a password
* I use a static buffer in this function. Plan accordingly.
*
* Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
*
* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
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*/
#include <termios.h>
#include "libbb.h"
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/* do nothing signal handler */
static void askpass_timeout(int ATTRIBUTE_UNUSED ignore)
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{
}
char *bb_askpass(int timeout, const char *prompt)
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{
/* Was static char[BIGNUM] */
enum { sizeof_passwd = 128 };
static char *passwd;
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char *ret;
int i;
struct sigaction sa, oldsa;
struct termios tio, oldtio;
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if (!passwd)
passwd = xmalloc(sizeof_passwd);
memset(passwd, 0, sizeof_passwd);
tcgetattr(STDIN_FILENO, &oldtio);
tcflush(STDIN_FILENO, TCIFLUSH);
tio = oldtio;
tio.c_iflag &= ~(IUCLC|IXON|IXOFF|IXANY);
tio.c_lflag &= ~(ECHO|ECHOE|ECHOK|ECHONL|TOSTOP);
tcsetattr(STDIN_FILENO, TCSANOW, &tio);
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memset(&sa, 0, sizeof(sa));
/* sa.sa_flags = 0; - no SA_RESTART! */
/* SIGINT and SIGALRM will interrupt read below */
sa.sa_handler = askpass_timeout;
sigaction(SIGINT, &sa, &oldsa);
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if (timeout) {
sigaction(SIGALRM, &sa, NULL);
alarm(timeout);
}
fputs(prompt, stdout);
fflush(stdout);
ret = NULL;
/* On timeout or Ctrl-C, read will hopefully be interrupted,
* and we return NULL */
if (read(STDIN_FILENO, passwd, sizeof_passwd - 1) > 0) {
ret = passwd;
i = 0;
/* Last byte is guaranteed to be 0
(read did not overwrite it) */
do {
if (passwd[i] == '\r' || passwd[i] == '\n')
passwd[i] = '\0';
} while (passwd[i++]);
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}
if (timeout) {
alarm(0);
}
sigaction(SIGINT, &oldsa, NULL);
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tcsetattr(STDIN_FILENO, TCSANOW, &oldtio);
bb_putchar('\n');
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fflush(stdout);
return ret;
}