glibc/misc/getpass.c

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/* Copyright (C) 1992, 1993, 1994, 1995 Free Software Foundation, Inc.
1995-02-18 01:27:10 +00:00
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
The GNU C Library 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If
not, write to the Free Software Foundation, Inc., 675 Mass Ave,
Cambridge, MA 02139, USA. */
#include <stdio.h>
#include <termios.h>
#include <unistd.h>
/* It is desireable to use this bit on systems that have it.
The only bit of terminal state we want to twiddle is echoing, which is
done in software; there is no need to change the state of the terminal
hardware. */
#ifndef TCSASOFT
#define TCSASOFT 0
#endif
char *
getpass (prompt)
const char *prompt;
{
FILE *in, *out;
struct termios t;
int echo_off;
static char *buf = NULL;
static size_t bufsize = 0;
ssize_t nread;
/* Try to write to and read from the terminal if we can.
If we can't open the terminal, use stderr and stdin. */
in = fopen ("/dev/tty", "w+");
if (in == NULL)
{
in = stdin;
out = stderr;
}
else
out = in;
/* Turn echoing off if it is on now. */
if (tcgetattr (fileno (in), &t) == 0)
{
if (t.c_lflag & ECHO)
{
t.c_lflag &= ~ECHO;
echo_off = tcsetattr (fileno (in), TCSAFLUSH|TCSASOFT, &t) == 0;
t.c_lflag |= ECHO;
}
else
echo_off = 0;
}
else
echo_off = 0;
/* Write the prompt. */
fputs (prompt, out);
fflush (out);
/* Read the password. */
nread = __getline (&buf, &bufsize, in);
if (buf != NULL)
if (nread < 0)
buf[0] = '\0';
else if (buf[nread - 1] == '\n')
{
/* Remove the newline. */
buf[nread - 1] = '\0';
if (echo_off)
/* Write the newline that was not echoed. */
putc ('\n', out);
}
1995-02-18 01:27:10 +00:00
/* Restore echoing. */
if (echo_off)
(void) tcsetattr (fileno (in), TCSAFLUSH|TCSASOFT, &t);
if (in != stdin)
/* We opened the terminal; now close it. */
fclose (in);
return buf;
}