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-rw-r--r--lib/util/term.c315
1 files changed, 315 insertions, 0 deletions
diff --git a/lib/util/term.c b/lib/util/term.c
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+/*
+ * SPDX-License-Identifier: ISC
+ *
+ * Copyright (c) 2011-2015, 2017-2020 Todd C. Miller <Todd.Miller@sudo.ws>
+ *
+ * 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.
+ */
+
+/*
+ * This is an open source non-commercial project. Dear PVS-Studio, please check it.
+ * PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
+ */
+
+#include <config.h>
+
+#include <sys/ioctl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <signal.h>
+#include <termios.h>
+#include <unistd.h>
+
+#include "sudo_compat.h"
+#include "sudo_debug.h"
+#include "sudo_util.h"
+
+/* TCSASOFT is a BSD extension that ignores control flags and speed. */
+#ifndef TCSASOFT
+# define TCSASOFT 0
+#endif
+
+/* Non-standard termios input flags */
+#ifndef IUCLC
+# define IUCLC 0
+#endif
+#ifndef IMAXBEL
+# define IMAXBEL 0
+#endif
+#ifndef IUTF8
+# define IUTF8 0
+#endif
+
+/* Non-standard termios output flags */
+#ifndef OLCUC
+# define OLCUC 0
+#endif
+#ifndef ONLCR
+# define ONLCR 0
+#endif
+#ifndef OCRNL
+# define OCRNL 0
+#endif
+#ifndef ONOCR
+# define ONOCR 0
+#endif
+#ifndef ONLRET
+# define ONLRET 0
+#endif
+
+/* Non-standard termios local flags */
+#ifndef XCASE
+# define XCASE 0
+#endif
+#ifndef IEXTEN
+# define IEXTEN 0
+#endif
+#ifndef ECHOCTL
+# define ECHOCTL 0
+#endif
+#ifndef ECHOKE
+# define ECHOKE 0
+#endif
+#ifndef PENDIN
+# define PENDIN 0
+#endif
+
+static struct termios oterm;
+static int changed;
+
+/* tgetpass() needs to know the erase and kill chars for cbreak mode. */
+sudo_dso_public int sudo_term_eof;
+sudo_dso_public int sudo_term_erase;
+sudo_dso_public int sudo_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)
+{
+ struct sigaction sa, osa;
+ int rc;
+ debug_decl(tcsetattr_nobg, SUDO_DEBUG_UTIL);
+
+ /*
+ * 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);
+
+ debug_return_int(rc);
+}
+
+/*
+ * Restore saved terminal settings if we are in the foreground process group.
+ * Returns true on success or false on failure.
+ */
+bool
+sudo_term_restore_v1(int fd, bool flush)
+{
+ debug_decl(sudo_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
+sudo_term_noecho_v1(int fd)
+{
+ struct termios term;
+ debug_decl(sudo_term_noecho, SUDO_DEBUG_UTIL);
+
+ 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, TCSASOFT|TCSADRAIN, &term) == 0) {
+ changed = 1;
+ debug_return_bool(true);
+ }
+ debug_return_bool(false);
+}
+
+/*
+ * Set terminal to raw mode with optional terminal signals.
+ * Returns true on success or false on failure.
+ */
+bool
+sudo_term_raw_v1(int fd, int isig)
+{
+ struct termios term;
+ debug_decl(sudo_term_raw, SUDO_DEBUG_UTIL);
+
+ if (!changed && tcgetattr(fd, &oterm) != 0)
+ debug_return_bool(false);
+ (void) memcpy(&term, &oterm, sizeof(term));
+ /* Set terminal to raw mode but optionally enable terminal signals. */
+ cfmakeraw(&term);
+ if (isig)
+ SET(term.c_lflag, ISIG);
+ if (tcsetattr_nobg(fd, TCSASOFT|TCSADRAIN, &term) == 0) {
+ changed = 1;
+ debug_return_bool(true);
+ }
+ debug_return_bool(false);
+}
+
+/*
+ * Set terminal to cbreak mode.
+ * Returns true on success or false on failure.
+ */
+bool
+sudo_term_cbreak_v1(int fd)
+{
+ struct termios term;
+ debug_decl(sudo_term_cbreak, SUDO_DEBUG_UTIL);
+
+ if (!changed && tcgetattr(fd, &oterm) != 0)
+ debug_return_bool(false);
+ (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, TCSASOFT|TCSADRAIN, &term) == 0) {
+ sudo_term_eof = term.c_cc[VEOF];
+ sudo_term_erase = term.c_cc[VERASE];
+ sudo_term_kill = term.c_cc[VKILL];
+ changed = 1;
+ debug_return_bool(true);
+ }
+ debug_return_bool(false);
+}
+
+/* Termios flags to copy between terminals. */
+#define INPUT_FLAGS (IGNPAR|PARMRK|INPCK|ISTRIP|INLCR|IGNCR|ICRNL|IUCLC|IXON|IXANY|IXOFF|IMAXBEL|IUTF8)
+#define OUTPUT_FLAGS (OPOST|OLCUC|ONLCR|OCRNL|ONOCR|ONLRET)
+#define CONTROL_FLAGS (CS7|CS8|PARENB|PARODD)
+#define LOCAL_FLAGS (ISIG|ICANON|XCASE|ECHO|ECHOE|ECHOK|ECHONL|NOFLSH|TOSTOP|IEXTEN|ECHOCTL|ECHOKE|PENDIN)
+
+/*
+ * Copy terminal settings from one descriptor to another.
+ * We cannot simply copy the struct termios as src and dst may be
+ * different terminal types (pseudo-tty vs. console or glass tty).
+ * Returns true on success or false on failure.
+ */
+bool
+sudo_term_copy_v1(int src, int dst)
+{
+ struct termios tt_src, tt_dst;
+ struct winsize wsize;
+ speed_t speed;
+ int i;
+ debug_decl(sudo_term_copy, SUDO_DEBUG_UTIL);
+
+ if (tcgetattr(src, &tt_src) != 0 || tcgetattr(dst, &tt_dst) != 0)
+ debug_return_bool(false);
+
+ /* Clear select input, output, control and local flags. */
+ CLR(tt_dst.c_iflag, INPUT_FLAGS);
+ CLR(tt_dst.c_oflag, OUTPUT_FLAGS);
+ CLR(tt_dst.c_cflag, CONTROL_FLAGS);
+ CLR(tt_dst.c_lflag, LOCAL_FLAGS);
+
+ /* Copy select input, output, control and local flags. */
+ SET(tt_dst.c_iflag, (tt_src.c_iflag & INPUT_FLAGS));
+ SET(tt_dst.c_oflag, (tt_src.c_oflag & OUTPUT_FLAGS));
+ SET(tt_dst.c_cflag, (tt_src.c_cflag & CONTROL_FLAGS));
+ SET(tt_dst.c_lflag, (tt_src.c_lflag & LOCAL_FLAGS));
+
+ /* Copy special chars from src verbatim. */
+ for (i = 0; i < NCCS; i++)
+ tt_dst.c_cc[i] = tt_src.c_cc[i];
+
+ /* Copy speed from src (zero output speed closes the connection). */
+ if ((speed = cfgetospeed(&tt_src)) == B0)
+ speed = B38400;
+ cfsetospeed(&tt_dst, speed);
+ speed = cfgetispeed(&tt_src);
+ cfsetispeed(&tt_dst, speed);
+
+ if (tcsetattr_nobg(dst, TCSASOFT|TCSAFLUSH, &tt_dst) == -1)
+ debug_return_bool(false);
+
+ if (ioctl(src, TIOCGWINSZ, &wsize) == 0)
+ (void)ioctl(dst, TIOCSWINSZ, &wsize);
+
+ debug_return_bool(true);
+}
+
+/*
+ * Returns true if fd refers to a tty in raw mode, else false.
+ */
+bool
+sudo_term_is_raw_v1(int fd)
+{
+ struct termios term;
+ debug_decl(sudo_term_is_raw, SUDO_DEBUG_UTIL);
+
+ if (tcgetattr(fd, &term) != 0)
+ debug_return_bool(false);
+
+ if (term.c_cc[VMIN] != 1 || term.c_cc[VTIME] != 0)
+ debug_return_bool(false);
+
+ if (ISSET(term.c_oflag, OPOST))
+ debug_return_bool(false);
+
+ if (ISSET(term.c_oflag, ECHO|ECHONL|ICANON))
+ debug_return_bool(false);
+
+ debug_return_bool(true);
+}
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