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/*
* Copyright (c) 2011-2014 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.
*/
#include <config.h>
#include <sys/types.h>
#include <stdio.h>
#ifdef STDC_HEADERS
# include <stdlib.h>
# include <stddef.h>
#else
# ifdef HAVE_STDLIB_H
# include <stdlib.h>
# endif
#endif /* STDC_HEADERS */
#ifdef HAVE_STRING_H
# if defined(HAVE_MEMORY_H) && !defined(STDC_HEADERS)
# include <memory.h>
# endif
# include <string.h>
#endif /* HAVE_STRING_H */
#ifdef HAVE_STRINGS_H
# include <strings.h>
#endif /* HAVE_STRINGS_H */
#include <errno.h>
#include <signal.h>
#include <termios.h>
#include <unistd.h>
#include "missing.h"
#include "sudo_debug.h"
#include "sudo_util.h"
#ifndef TCSASOFT
# define TCSASOFT 0
#endif
#ifndef ECHONL
# define ECHONL 0
#endif
#ifndef IEXTEN
# define IEXTEN 0
#endif
#ifndef IUCLC
# define IUCLC 0
#endif
#ifndef _POSIX_VDISABLE
# ifdef VDISABLE
# define _POSIX_VDISABLE VDISABLE
# else
# define _POSIX_VDISABLE 0
# endif
#endif
static struct termios term, oterm;
static int changed;
/* tgetpass() needs to know the erase and kill chars for cbreak mode. */
int term_erase;
int term_kill;
static volatile sig_atomic_t got_sigttou;
/*
* SIGTTOU signal handler for term_restore that just sets a flag.
*/
static void sigttou(int signo)
{
got_sigttou = 1;
}
/*
* Like tcsetattr() but restarts on EINTR _except_ for SIGTTOU.
* Returns 0 on success or -1 on failure, setting errno.
* Sets got_sigttou on failure if interrupted by SIGTTOU.
*/
static int
tcsetattr_nobg(int fd, int flags, struct termios *tp)
{
sigaction_t sa, osa;
int rc;
/*
* If we receive SIGTTOU from tcsetattr() it means we are
* not in the foreground process group.
* This should be less racy than using tcgetpgrp().
*/
memset(&sa, 0, sizeof(sa));
sigemptyset(&sa.sa_mask);
sa.sa_handler = sigttou;
got_sigttou = 0;
sigaction(SIGTTOU, &sa, &osa);
do {
rc = tcsetattr(fd, flags, tp);
} while (rc != 0 && errno == EINTR && !got_sigttou);
sigaction(SIGTTOU, &osa, NULL);
return rc;
}
/*
* Restore saved terminal settings if we are in the foreground process group.
* Returns true on success or false on failure.
*/
bool
term_restore(int fd, bool flush)
{
debug_decl(term_restore, SUDO_DEBUG_UTIL)
if (changed) {
const int flags = flush ? (TCSASOFT|TCSAFLUSH) : (TCSASOFT|TCSADRAIN);
if (tcsetattr_nobg(fd, flags, &oterm) != 0)
debug_return_bool(false);
changed = 0;
}
debug_return_bool(true);
}
/*
* Disable terminal echo.
* Returns true on success or false on failure.
*/
bool
term_noecho(int fd)
{
debug_decl(term_noecho, SUDO_DEBUG_UTIL)
again:
if (!changed && tcgetattr(fd, &oterm) != 0)
debug_return_bool(false);
(void) memcpy(&term, &oterm, sizeof(term));
CLR(term.c_lflag, ECHO|ECHONL);
#ifdef VSTATUS
term.c_cc[VSTATUS] = _POSIX_VDISABLE;
#endif
if (tcsetattr_nobg(fd, TCSADRAIN|TCSASOFT, &term) == 0) {
changed = 1;
debug_return_bool(true);
}
if (got_sigttou) {
/* We were in the background, so oterm is probably bogus. */
kill(getpid(), SIGTTOU);
goto again;
}
debug_return_bool(false);
}
/*
* Set terminal to raw mode.
* Returns true on success or false on failure.
*/
bool
term_raw(int fd, int isig)
{
struct termios term;
debug_decl(term_raw, SUDO_DEBUG_UTIL)
again:
if (!changed && tcgetattr(fd, &oterm) != 0)
return 0;
(void) memcpy(&term, &oterm, sizeof(term));
/* Set terminal to raw mode */
term.c_cc[VMIN] = 1;
term.c_cc[VTIME] = 0;
CLR(term.c_iflag, ICRNL | IGNCR | INLCR | IUCLC | IXON);
CLR(term.c_oflag, OPOST);
CLR(term.c_lflag, ECHO | ICANON | ISIG | IEXTEN);
if (isig)
SET(term.c_lflag, ISIG);
if (tcsetattr_nobg(fd, TCSADRAIN|TCSASOFT, &term) == 0) {
changed = 1;
debug_return_bool(true);
}
if (got_sigttou) {
/* We were in the background, so oterm is probably bogus. */
kill(getpid(), SIGTTOU);
goto again;
}
debug_return_bool(false);
}
/*
* Set terminal to cbreak mode.
* Returns true on success or false on failure.
*/
bool
term_cbreak(int fd)
{
debug_decl(term_cbreak, SUDO_DEBUG_UTIL)
again:
if (!changed && tcgetattr(fd, &oterm) != 0)
return 0;
(void) memcpy(&term, &oterm, sizeof(term));
/* Set terminal to half-cooked mode */
term.c_cc[VMIN] = 1;
term.c_cc[VTIME] = 0;
/* cppcheck-suppress redundantAssignment */
CLR(term.c_lflag, ECHO | ECHONL | ICANON | IEXTEN);
/* cppcheck-suppress redundantAssignment */
SET(term.c_lflag, ISIG);
#ifdef VSTATUS
term.c_cc[VSTATUS] = _POSIX_VDISABLE;
#endif
if (tcsetattr_nobg(fd, TCSADRAIN|TCSASOFT, &term) == 0) {
term_erase = term.c_cc[VERASE];
term_kill = term.c_cc[VKILL];
changed = 1;
debug_return_bool(true);
}
if (got_sigttou) {
/* We were in the background, so oterm is probably bogus. */
kill(getpid(), SIGTTOU);
goto again;
}
debug_return_bool(false);
}
/*
* Copy terminal settings from one descriptor to another.
* Returns true on success or false on failure.
*/
bool
term_copy(int src, int dst)
{
struct termios tt;
debug_decl(term_copy, SUDO_DEBUG_UTIL)
again:
if (tcgetattr(src, &tt) != 0)
debug_return_bool(false);
if (tcsetattr_nobg(dst, TCSANOW|TCSASOFT, &tt) == 0)
debug_return_bool(true);
if (got_sigttou) {
/* We were in the background, so oterm is probably bogus. */
kill(getpid(), SIGTTOU);
goto again;
}
debug_return_bool(false);
}
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