diff options
Diffstat (limited to '')
| -rw-r--r-- | lib/util/term.c | 491 |
1 files changed, 491 insertions, 0 deletions
diff --git a/lib/util/term.c b/lib/util/term.c new file mode 100644 index 0000000..a74e9d0 --- /dev/null +++ b/lib/util/term.c @@ -0,0 +1,491 @@ +/* + * SPDX-License-Identifier: ISC + * + * Copyright (c) 2011-2015, 2017-2023 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 <sys/stat.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 + +/* 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) + +static struct termios orig_term; +static struct termios cur_term; +static bool 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 tcsetattr_nobg() 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 == -1 && 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) +{ + const int flags = flush ? (TCSASOFT|TCSAFLUSH) : (TCSASOFT|TCSADRAIN); + struct termios term = { 0 }; + bool ret = false; + debug_decl(sudo_term_restore, SUDO_DEBUG_UTIL); + + if (!changed) + debug_return_bool(true); + + sudo_lock_file(fd, SUDO_LOCK); + + /* Avoid changing term settings if changed out from under us. */ + if (tcgetattr(fd, &term) == -1) { + sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_ERRNO, + "%s: tcgetattr(%d)", __func__, fd); + goto unlock; + } + if ((term.c_iflag & INPUT_FLAGS) != (cur_term.c_iflag & INPUT_FLAGS)) { + sudo_debug_printf(SUDO_DEBUG_INFO, "%s: not restoring terminal, " + "c_iflag changed; 0x%x, expected 0x%x", __func__, + (unsigned int)term.c_iflag, (unsigned int)cur_term.c_iflag); + /* Not an error. */ + ret = true; + goto unlock; + } + if ((term.c_oflag & OUTPUT_FLAGS) != (cur_term.c_oflag & OUTPUT_FLAGS)) { + sudo_debug_printf(SUDO_DEBUG_INFO, "%s: not restoring terminal, " + "c_oflag changed; 0x%x, expected 0x%x", __func__, + (unsigned int)term.c_oflag, (unsigned int)cur_term.c_oflag); + /* Not an error. */ + ret = true; + goto unlock; + } +#if !TCSASOFT + /* Only systems without TCSASOFT make changes to c_cflag. */ + if ((term.c_cflag & CONTROL_FLAGS) != (cur_term.c_cflag & CONTROL_FLAGS)) { + sudo_debug_printf(SUDO_DEBUG_INFO, "%s: not restoring terminal, " + "c_cflag changed; 0x%x, expected 0x%x", __func__, + (unsigned int)term.c_cflag, (unsigned int)cur_term.c_cflag); + /* Not an error. */ + ret = true; + goto unlock; + } +#endif + if ((term.c_lflag & LOCAL_FLAGS) != (cur_term.c_lflag & LOCAL_FLAGS)) { + sudo_debug_printf(SUDO_DEBUG_INFO, "%s: not restoring terminal, " + "c_lflag changed; 0x%x, expected 0x%x", __func__, + (unsigned int)term.c_lflag, (unsigned int)cur_term.c_lflag); + /* Not an error. */ + ret = true; + goto unlock; + } + if (memcmp(term.c_cc, cur_term.c_cc, sizeof(term.c_cc)) != 0) { + sudo_debug_printf(SUDO_DEBUG_INFO, + "%s: not restoring terminal, c_cc[] changed", __func__); + /* Not an error. */ + ret = true; + goto unlock; + } + + if (tcsetattr_nobg(fd, flags, &orig_term) == -1) { + sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_ERRNO, + "%s: tcsetattr(%d)", __func__, fd); + goto unlock; + } + cur_term = orig_term; + changed = false; + ret = true; + +unlock: + sudo_lock_file(fd, SUDO_UNLOCK); + + debug_return_bool(ret); +} + +/* + * Disable terminal echo. + * Returns true on success or false on failure. + */ +bool +sudo_term_noecho_v1(int fd) +{ + struct termios term = { 0 }; + bool ret = false; + debug_decl(sudo_term_noecho, SUDO_DEBUG_UTIL); + + sudo_lock_file(fd, SUDO_LOCK); + if (!changed && tcgetattr(fd, &orig_term) == -1) { + sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_ERRNO, + "%s: tcgetattr(%d)", __func__, fd); + goto unlock; + } + + term = orig_term; + CLR(term.c_lflag, ECHO|ECHONL); +#ifdef VSTATUS + term.c_cc[VSTATUS] = _POSIX_VDISABLE; +#endif + if (tcsetattr_nobg(fd, TCSASOFT|TCSADRAIN, &term) == -1) { + sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_ERRNO, + "%s: tcsetattr(%d)", __func__, fd); + goto unlock; + } + cur_term = term; + changed = true; + ret = true; + +unlock: + sudo_lock_file(fd, SUDO_UNLOCK); + debug_return_bool(ret); +} + +/* + * Returns true if term is in raw mode, else false. + */ +static bool +sudo_term_is_raw_int(struct termios *term) +{ + debug_decl(sudo_term_is_raw_int, SUDO_DEBUG_UTIL); + + 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); +} + +/* + * Returns true if fd refers to a tty in raw mode, else false. + */ +bool +sudo_term_is_raw_v1(int fd) +{ + struct termios term = { 0 }; + debug_decl(sudo_term_is_raw, SUDO_DEBUG_UTIL); + + if (!sudo_isatty(fd, NULL)) + debug_return_bool(false); + + sudo_lock_file(fd, SUDO_LOCK); + if (tcgetattr(fd, &term) == -1) { + sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_ERRNO, + "%s: tcgetattr(%d)", __func__, fd); + sudo_lock_file(fd, SUDO_UNLOCK); + debug_return_bool(false); + } + sudo_lock_file(fd, SUDO_UNLOCK); + + debug_return_bool(sudo_term_is_raw_int(&term)); +} + +/* + * Set terminal to raw mode as modified by flags. + * Returns true on success or false on failure. + */ +bool +sudo_term_raw_v1(int fd, unsigned int flags) +{ + struct termios term = { 0 }; + bool ret = false; + tcflag_t oflag; + debug_decl(sudo_term_raw, SUDO_DEBUG_UTIL); + + sudo_lock_file(fd, SUDO_LOCK); + if (!changed && tcgetattr(fd, &orig_term) == -1) { + sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_ERRNO, + "%s: tcgetattr(%d)", __func__, fd); + goto unlock; + } + + if (sudo_term_is_raw_int(&term)) { + sudo_debug_printf(SUDO_DEBUG_INFO, "%s: fd %d already in raw mode", + __func__, fd); + ret = true; + goto unlock; + } + + /* + * Set terminal to raw mode but optionally enable terminal signals + * and/or preserve output flags. + */ + term = orig_term; + oflag = term.c_oflag; + cfmakeraw(&term); + if (ISSET(flags, SUDO_TERM_ISIG)) + SET(term.c_lflag, ISIG); + if (ISSET(flags, SUDO_TERM_OFLAG)) + term.c_oflag = oflag; + if (tcsetattr_nobg(fd, TCSASOFT|TCSADRAIN, &term) == -1) { + sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_ERRNO, + "%s: tcsetattr(%d)", __func__, fd); + goto unlock; + } + cur_term = term; + changed = true; + ret = true; + +unlock: + sudo_lock_file(fd, SUDO_UNLOCK); + debug_return_bool(ret); +} + +/* + * Set terminal to cbreak mode. + * Returns true on success or false on failure. + */ +bool +sudo_term_cbreak_v1(int fd) +{ + struct termios term = { 0 }; + bool ret = false; + debug_decl(sudo_term_cbreak, SUDO_DEBUG_UTIL); + + sudo_lock_file(fd, SUDO_LOCK); + if (!changed && tcgetattr(fd, &orig_term) == -1) { + sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_ERRNO, + "%s: tcgetattr(%d)", __func__, fd); + goto unlock; + } + + /* Set terminal to half-cooked mode */ + term = orig_term; + 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) == -1) { + sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_ERRNO, + "%s: tcsetattr(%d)", __func__, fd); + goto unlock; + } + sudo_term_eof = term.c_cc[VEOF]; + sudo_term_erase = term.c_cc[VERASE]; + sudo_term_kill = term.c_cc[VKILL]; + cur_term = term; + changed = true; + ret = true; + +unlock: + sudo_lock_file(fd, SUDO_UNLOCK); + debug_return_bool(ret); +} + +/* + * 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; + unsigned int i; + bool ret = false; + debug_decl(sudo_term_copy, SUDO_DEBUG_UTIL); + + sudo_lock_file(src, SUDO_LOCK); + sudo_lock_file(dst, SUDO_LOCK); + if (tcgetattr(src, &tt_src) == -1 || tcgetattr(dst, &tt_dst) == -1) { + sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_ERRNO, + "%s: tcgetattr", __func__); + goto unlock; + } + + /* 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) { + sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_ERRNO, + "%s: tcsetattr(%d)", __func__, dst); + goto unlock; + } + ret = true; + + if (ioctl(src, TIOCGWINSZ, &wsize) == 0) + (void)ioctl(dst, IOCTL_REQ_CAST TIOCSWINSZ, &wsize); + +unlock: + sudo_lock_file(dst, SUDO_UNLOCK); + sudo_lock_file(src, SUDO_UNLOCK); + debug_return_bool(ret); +} + +/* + * Like isatty(3) but stats the fd and stores the result in sb. + * Only calls isatty(3) if fd is a character special device. + * Returns true if a tty, else returns false and sets errno. + */ +bool +sudo_isatty_v1(int fd, struct stat *sbp) +{ + bool ret = false; + struct stat sb; + debug_decl(sudo_isatty, SUDO_DEBUG_EXEC); + + if (sbp == NULL) + sbp = &sb; + + if (fstat(fd, sbp) == 0) { + if (!S_ISCHR(sbp->st_mode)) { + errno = ENOTTY; + } else { + ret = isatty(fd) == 1; + } + } else if (sbp != &sb) { + /* Always initialize sbp. */ + memset(sbp, 0, sizeof(*sbp)); + } + debug_return_bool(ret); +} |