Add readpassphrase.c in src/ext

This is taken verbatim from openssh 6.8p1, which appears to have
lightly tweaked it from the openbsd version.

LICENSE

@@ -249,7 +249,26 @@ As a special exception to the GNU General Public License, if you
 distribute this file as part of a program that contains a
 configuration script generated by Autoconf, you may include it under
 the same distribution terms that you use for the rest of that program.
+===============================================================================
+src/ext/readpassphrase.[ch] are distributed under this license:
+
+  Copyright (c) 2000-2002, 2007 Todd C. Miller <Todd.Miller@courtesan.com>
+
+  Permission to use, copy, modify, and distribute this software for any
+  purpose with or without fee is hereby granted, provided that the above
+  copyright notice and this permission notice appear in all copies.
+
+  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 
+  Sponsored in part by the Defense Advanced Research Projects
+  Agency (DARPA) and Air Force Research Laboratory, Air Force
+  Materiel Command, USAF, under agreement number F39502-99-1-0512.
 
 ===============================================================================
 If you got Tor as a static binary with OpenSSL included, then you should know:

src/ext/README

@@ -60,4 +60,7 @@ ed25519/ref10/*
     Daniel Bernsten's portable ref10 implementation of ed25519.
     Public domain.
 
+readpassphrase.[ch]
 
+    Portable readpassphrase implementation from OpenSSH portable, version
+    6.8p1.

src/ext/include.am

@@ -7,6 +7,7 @@ EXTHEADERS = \
   src/ext/ht.h		\
   src/ext/eventdns.h	\
   src/ext/tinytest.h	\
+  src/ext/readpassphrase.h \
   src/ext/strlcat.c	\
   src/ext/strlcpy.c	\
   src/ext/tinytest_macros.h \

src/ext/readpassphrase.c

+/*	$OpenBSD: readpassphrase.c,v 1.22 2010/01/13 10:20:54 dtucker Exp $	*/
+
+/*
+ * Copyright (c) 2000-2002, 2007 Todd C. Miller <Todd.Miller@courtesan.com>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ * Sponsored in part by the Defense Advanced Research Projects
+ * Agency (DARPA) and Air Force Research Laboratory, Air Force
+ * Materiel Command, USAF, under agreement number F39502-99-1-0512.
+ */
+
+/* OPENBSD ORIGINAL: lib/libc/gen/readpassphrase.c */
+
+#include "includes.h"
+
+#ifndef HAVE_READPASSPHRASE
+
+#include <termios.h>
+#include <signal.h>
+#include <ctype.h>
+#include <fcntl.h>
+#include <readpassphrase.h>
+#include <errno.h>
+#include <string.h>
+#include <unistd.h>
+
+#ifdef TCSASOFT
+# define _T_FLUSH	(TCSAFLUSH|TCSASOFT)
+#else
+# define _T_FLUSH	(TCSAFLUSH)
+#endif
+
+/* SunOS 4.x which lacks _POSIX_VDISABLE, but has VDISABLE */
+#if !defined(_POSIX_VDISABLE) && defined(VDISABLE)
+#  define _POSIX_VDISABLE       VDISABLE
+#endif
+
+#ifndef _NSIG
+# ifdef NSIG
+#  define _NSIG NSIG
+# else
+#  define _NSIG 128
+# endif
+#endif
+
+static volatile sig_atomic_t signo[_NSIG];
+
+static void handler(int);
+
+char *
+readpassphrase(const char *prompt, char *buf, size_t bufsiz, int flags)
+{
+	ssize_t nr;
+	int input, output, save_errno, i, need_restart;
+	char ch, *p, *end;
+	struct termios term, oterm;
+	struct sigaction sa, savealrm, saveint, savehup, savequit, saveterm;
+	struct sigaction savetstp, savettin, savettou, savepipe;
+
+	/* I suppose we could alloc on demand in this case (XXX). */
+	if (bufsiz == 0) {
+		errno = EINVAL;
+		return(NULL);
+	}
+
+restart:
+	for (i = 0; i < _NSIG; i++)
+		signo[i] = 0;
+	nr = -1;
+	save_errno = 0;
+	need_restart = 0;
+	/*
+	 * Read and write to /dev/tty if available.  If not, read from
+	 * stdin and write to stderr unless a tty is required.
+	 */
+	if ((flags & RPP_STDIN) ||
+	    (input = output = open(_PATH_TTY, O_RDWR)) == -1) {
+		if (flags & RPP_REQUIRE_TTY) {
+			errno = ENOTTY;
+			return(NULL);
+		}
+		input = STDIN_FILENO;
+		output = STDERR_FILENO;
+	}
+
+	/*
+	 * Catch signals that would otherwise cause the user to end
+	 * up with echo turned off in the shell.  Don't worry about
+	 * things like SIGXCPU and SIGVTALRM for now.
+	 */
+	sigemptyset(&sa.sa_mask);
+	sa.sa_flags = 0;		/* don't restart system calls */
+	sa.sa_handler = handler;
+	(void)sigaction(SIGALRM, &sa, &savealrm);
+	(void)sigaction(SIGHUP, &sa, &savehup);
+	(void)sigaction(SIGINT, &sa, &saveint);
+	(void)sigaction(SIGPIPE, &sa, &savepipe);
+	(void)sigaction(SIGQUIT, &sa, &savequit);
+	(void)sigaction(SIGTERM, &sa, &saveterm);
+	(void)sigaction(SIGTSTP, &sa, &savetstp);
+	(void)sigaction(SIGTTIN, &sa, &savettin);
+	(void)sigaction(SIGTTOU, &sa, &savettou);
+
+	/* Turn off echo if possible. */
+	if (input != STDIN_FILENO && tcgetattr(input, &oterm) == 0) {
+		memcpy(&term, &oterm, sizeof(term));
+		if (!(flags & RPP_ECHO_ON))
+			term.c_lflag &= ~(ECHO | ECHONL);
+#ifdef VSTATUS
+		if (term.c_cc[VSTATUS] != _POSIX_VDISABLE)
+			term.c_cc[VSTATUS] = _POSIX_VDISABLE;
+#endif
+		(void)tcsetattr(input, _T_FLUSH, &term);
+	} else {
+		memset(&term, 0, sizeof(term));
+		term.c_lflag |= ECHO;
+		memset(&oterm, 0, sizeof(oterm));
+		oterm.c_lflag |= ECHO;
+	}
+
+	/* No I/O if we are already backgrounded. */
+	if (signo[SIGTTOU] != 1 && signo[SIGTTIN] != 1) {
+		if (!(flags & RPP_STDIN))
+			(void)write(output, prompt, strlen(prompt));
+		end = buf + bufsiz - 1;
+		p = buf;
+		while ((nr = read(input, &ch, 1)) == 1 && ch != '\n' && ch != '\r') {
+			if (p < end) {
+				if ((flags & RPP_SEVENBIT))
+					ch &= 0x7f;
+				if (isalpha(ch)) {
+					if ((flags & RPP_FORCELOWER))
+						ch = (char)tolower(ch);
+					if ((flags & RPP_FORCEUPPER))
+						ch = (char)toupper(ch);
+				}
+				*p++ = ch;
+			}
+		}
+		*p = '\0';
+		save_errno = errno;
+		if (!(term.c_lflag & ECHO))
+			(void)write(output, "\n", 1);
+	}
+
+	/* Restore old terminal settings and signals. */
+	if (memcmp(&term, &oterm, sizeof(term)) != 0) {
+		while (tcsetattr(input, _T_FLUSH, &oterm) == -1 &&
+		    errno == EINTR)
+			continue;
+	}
+	(void)sigaction(SIGALRM, &savealrm, NULL);
+	(void)sigaction(SIGHUP, &savehup, NULL);
+	(void)sigaction(SIGINT, &saveint, NULL);
+	(void)sigaction(SIGQUIT, &savequit, NULL);
+	(void)sigaction(SIGPIPE, &savepipe, NULL);
+	(void)sigaction(SIGTERM, &saveterm, NULL);
+	(void)sigaction(SIGTSTP, &savetstp, NULL);
+	(void)sigaction(SIGTTIN, &savettin, NULL);
+	(void)sigaction(SIGTTOU, &savettou, NULL);
+	if (input != STDIN_FILENO)
+		(void)close(input);
+
+	/*
+	 * If we were interrupted by a signal, resend it to ourselves
+	 * now that we have restored the signal handlers.
+	 */
+	for (i = 0; i < _NSIG; i++) {
+		if (signo[i]) {
+			kill(getpid(), i);
+			switch (i) {
+			case SIGTSTP:
+			case SIGTTIN:
+			case SIGTTOU:
+				need_restart = 1;
+			}
+		}
+	}
+	if (need_restart)
+		goto restart;
+
+	if (save_errno)
+		errno = save_errno;
+	return(nr == -1 ? NULL : buf);
+}
+
+#if 0
+char *
+getpass(const char *prompt)
+{
+	static char buf[_PASSWORD_LEN + 1];
+
+	return(readpassphrase(prompt, buf, sizeof(buf), RPP_ECHO_OFF));
+}
+#endif
+
+static void handler(int s)
+{
+
+	signo[s] = 1;
+}
+#endif /* HAVE_READPASSPHRASE */

src/ext/readpassphrase.h

+/*	$OpenBSD: readpassphrase.h,v 1.5 2003/06/17 21:56:23 millert Exp $	*/
+
+/*
+ * Copyright (c) 2000, 2002 Todd C. Miller <Todd.Miller@courtesan.com>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ * Sponsored in part by the Defense Advanced Research Projects
+ * Agency (DARPA) and Air Force Research Laboratory, Air Force
+ * Materiel Command, USAF, under agreement number F39502-99-1-0512.
+ */
+
+/* OPENBSD ORIGINAL: include/readpassphrase.h */
+
+#ifndef _READPASSPHRASE_H_
+#define _READPASSPHRASE_H_
+
+#include "includes.h"
+
+#ifndef HAVE_READPASSPHRASE
+
+#define RPP_ECHO_OFF    0x00		/* Turn off echo (default). */
+#define RPP_ECHO_ON     0x01		/* Leave echo on. */
+#define RPP_REQUIRE_TTY 0x02		/* Fail if there is no tty. */
+#define RPP_FORCELOWER  0x04		/* Force input to lower case. */
+#define RPP_FORCEUPPER  0x08		/* Force input to upper case. */
+#define RPP_SEVENBIT    0x10		/* Strip the high bit from input. */
+#define RPP_STDIN       0x20		/* Read from stdin, not /dev/tty */
+
+char * readpassphrase(const char *, char *, size_t, int);
+
+#endif /* HAVE_READPASSPHRASE */
+
+#endif /* !_READPASSPHRASE_H_ */