/* SPDX-License-Identifier: LGPL-2.1+ */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "alloc-util.h" #include "copy.h" #include "def.h" #include "env-util.h" #include "fd-util.h" #include "fileio.h" #include "fs-util.h" #include "io-util.h" #include "log.h" #include "macro.h" #include "parse-util.h" #include "path-util.h" #include "proc-cmdline.h" #include "process-util.h" #include "socket-util.h" #include "stat-util.h" #include "string-util.h" #include "strv.h" #include "terminal-util.h" #include "time-util.h" #include "util.h" static volatile unsigned cached_columns = 0; static volatile unsigned cached_lines = 0; static volatile int cached_on_tty = -1; static volatile int cached_colors_enabled = -1; static volatile int cached_underline_enabled = -1; int chvt(int vt) { _cleanup_close_ int fd; /* Switch to the specified vt number. If the VT is specified <= 0 switch to the VT the kernel log messages go, * if that's configured. */ fd = open_terminal("/dev/tty0", O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK); if (fd < 0) return -errno; if (vt <= 0) { int tiocl[2] = { TIOCL_GETKMSGREDIRECT, 0 }; if (ioctl(fd, TIOCLINUX, tiocl) < 0) return -errno; vt = tiocl[0] <= 0 ? 1 : tiocl[0]; } if (ioctl(fd, VT_ACTIVATE, vt) < 0) return -errno; return 0; } int read_one_char(FILE *f, char *ret, usec_t t, bool *need_nl) { _cleanup_free_ char *line = NULL; struct termios old_termios; int r; assert(f); assert(ret); /* If this is a terminal, then switch canonical mode off, so that we can read a single character */ if (tcgetattr(fileno(f), &old_termios) >= 0) { struct termios new_termios = old_termios; new_termios.c_lflag &= ~ICANON; new_termios.c_cc[VMIN] = 1; new_termios.c_cc[VTIME] = 0; if (tcsetattr(fileno(f), TCSADRAIN, &new_termios) >= 0) { char c; if (t != USEC_INFINITY) { if (fd_wait_for_event(fileno(f), POLLIN, t) <= 0) { (void) tcsetattr(fileno(f), TCSADRAIN, &old_termios); return -ETIMEDOUT; } } r = safe_fgetc(f, &c); (void) tcsetattr(fileno(f), TCSADRAIN, &old_termios); if (r < 0) return r; if (r == 0) return -EIO; if (need_nl) *need_nl = c != '\n'; *ret = c; return 0; } } if (t != USEC_INFINITY) { if (fd_wait_for_event(fileno(f), POLLIN, t) <= 0) return -ETIMEDOUT; } /* If this is not a terminal, then read a full line instead */ r = read_line(f, 16, &line); /* longer than necessary, to eat up UTF-8 chars/vt100 key sequences */ if (r < 0) return r; if (r == 0) return -EIO; if (strlen(line) != 1) return -EBADMSG; if (need_nl) *need_nl = false; *ret = line[0]; return 0; } #define DEFAULT_ASK_REFRESH_USEC (2*USEC_PER_SEC) int ask_char(char *ret, const char *replies, const char *fmt, ...) { int r; assert(ret); assert(replies); assert(fmt); for (;;) { va_list ap; char c; bool need_nl = true; if (colors_enabled()) fputs(ANSI_HIGHLIGHT, stdout); putchar('\r'); va_start(ap, fmt); vprintf(fmt, ap); va_end(ap); if (colors_enabled()) fputs(ANSI_NORMAL, stdout); fflush(stdout); r = read_one_char(stdin, &c, DEFAULT_ASK_REFRESH_USEC, &need_nl); if (r < 0) { if (r == -ETIMEDOUT) continue; if (r == -EBADMSG) { puts("Bad input, please try again."); continue; } putchar('\n'); return r; } if (need_nl) putchar('\n'); if (strchr(replies, c)) { *ret = c; return 0; } puts("Read unexpected character, please try again."); } } int ask_string(char **ret, const char *text, ...) { int r; assert(ret); assert(text); for (;;) { _cleanup_free_ char *line = NULL; va_list ap; if (colors_enabled()) fputs(ANSI_HIGHLIGHT, stdout); va_start(ap, text); vprintf(text, ap); va_end(ap); if (colors_enabled()) fputs(ANSI_NORMAL, stdout); fflush(stdout); r = read_line(stdin, LONG_LINE_MAX, &line); if (r < 0) return r; if (r == 0) return -EIO; if (!isempty(line)) { *ret = TAKE_PTR(line); return 0; } } } int reset_terminal_fd(int fd, bool switch_to_text) { struct termios termios; int r = 0; /* Set terminal to some sane defaults */ assert(fd >= 0); /* We leave locked terminal attributes untouched, so that * Plymouth may set whatever it wants to set, and we don't * interfere with that. */ /* Disable exclusive mode, just in case */ (void) ioctl(fd, TIOCNXCL); /* Switch to text mode */ if (switch_to_text) (void) ioctl(fd, KDSETMODE, KD_TEXT); /* Set default keyboard mode */ (void) vt_reset_keyboard(fd); if (tcgetattr(fd, &termios) < 0) { r = -errno; goto finish; } /* We only reset the stuff that matters to the software. How * hardware is set up we don't touch assuming that somebody * else will do that for us */ termios.c_iflag &= ~(IGNBRK | BRKINT | ISTRIP | INLCR | IGNCR | IUCLC); termios.c_iflag |= ICRNL | IMAXBEL | IUTF8; termios.c_oflag |= ONLCR; termios.c_cflag |= CREAD; termios.c_lflag = ISIG | ICANON | IEXTEN | ECHO | ECHOE | ECHOK | ECHOCTL | ECHOPRT | ECHOKE; termios.c_cc[VINTR] = 03; /* ^C */ termios.c_cc[VQUIT] = 034; /* ^\ */ termios.c_cc[VERASE] = 0177; termios.c_cc[VKILL] = 025; /* ^X */ termios.c_cc[VEOF] = 04; /* ^D */ termios.c_cc[VSTART] = 021; /* ^Q */ termios.c_cc[VSTOP] = 023; /* ^S */ termios.c_cc[VSUSP] = 032; /* ^Z */ termios.c_cc[VLNEXT] = 026; /* ^V */ termios.c_cc[VWERASE] = 027; /* ^W */ termios.c_cc[VREPRINT] = 022; /* ^R */ termios.c_cc[VEOL] = 0; termios.c_cc[VEOL2] = 0; termios.c_cc[VTIME] = 0; termios.c_cc[VMIN] = 1; if (tcsetattr(fd, TCSANOW, &termios) < 0) r = -errno; finish: /* Just in case, flush all crap out */ (void) tcflush(fd, TCIOFLUSH); return r; } int reset_terminal(const char *name) { _cleanup_close_ int fd = -1; /* We open the terminal with O_NONBLOCK here, to ensure we * don't block on carrier if this is a terminal with carrier * configured. */ fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK); if (fd < 0) return fd; return reset_terminal_fd(fd, true); } int open_terminal(const char *name, int mode) { unsigned c = 0; int fd; /* * If a TTY is in the process of being closed opening it might * cause EIO. This is horribly awful, but unlikely to be * changed in the kernel. Hence we work around this problem by * retrying a couple of times. * * https://bugs.launchpad.net/ubuntu/+source/linux/+bug/554172/comments/245 */ if (mode & O_CREAT) return -EINVAL; for (;;) { fd = open(name, mode, 0); if (fd >= 0) break; if (errno != EIO) return -errno; /* Max 1s in total */ if (c >= 20) return -errno; usleep(50 * USEC_PER_MSEC); c++; } if (isatty(fd) <= 0) { safe_close(fd); return -ENOTTY; } return fd; } int acquire_terminal( const char *name, AcquireTerminalFlags flags, usec_t timeout) { _cleanup_close_ int notify = -1, fd = -1; usec_t ts = USEC_INFINITY; int r, wd = -1; assert(name); assert(IN_SET(flags & ~ACQUIRE_TERMINAL_PERMISSIVE, ACQUIRE_TERMINAL_TRY, ACQUIRE_TERMINAL_FORCE, ACQUIRE_TERMINAL_WAIT)); /* We use inotify to be notified when the tty is closed. We create the watch before checking if we can actually * acquire it, so that we don't lose any event. * * Note: strictly speaking this actually watches for the device being closed, it does *not* really watch * whether a tty loses its controlling process. However, unless some rogue process uses TIOCNOTTY on /dev/tty * *after* closing its tty otherwise this will not become a problem. As long as the administrator makes sure to * not configure any service on the same tty as an untrusted user this should not be a problem. (Which they * probably should not do anyway.) */ if ((flags & ~ACQUIRE_TERMINAL_PERMISSIVE) == ACQUIRE_TERMINAL_WAIT) { notify = inotify_init1(IN_CLOEXEC | (timeout != USEC_INFINITY ? IN_NONBLOCK : 0)); if (notify < 0) return -errno; wd = inotify_add_watch(notify, name, IN_CLOSE); if (wd < 0) return -errno; if (timeout != USEC_INFINITY) ts = now(CLOCK_MONOTONIC); } for (;;) { struct sigaction sa_old, sa_new = { .sa_handler = SIG_IGN, .sa_flags = SA_RESTART, }; if (notify >= 0) { r = flush_fd(notify); if (r < 0) return r; } /* We pass here O_NOCTTY only so that we can check the return value TIOCSCTTY and have a reliable way * to figure out if we successfully became the controlling process of the tty */ fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC); if (fd < 0) return fd; /* Temporarily ignore SIGHUP, so that we don't get SIGHUP'ed if we already own the tty. */ assert_se(sigaction(SIGHUP, &sa_new, &sa_old) == 0); /* First, try to get the tty */ r = ioctl(fd, TIOCSCTTY, (flags & ~ACQUIRE_TERMINAL_PERMISSIVE) == ACQUIRE_TERMINAL_FORCE) < 0 ? -errno : 0; /* Reset signal handler to old value */ assert_se(sigaction(SIGHUP, &sa_old, NULL) == 0); /* Success? Exit the loop now! */ if (r >= 0) break; /* Any failure besides -EPERM? Fail, regardless of the mode. */ if (r != -EPERM) return r; if (flags & ACQUIRE_TERMINAL_PERMISSIVE) /* If we are in permissive mode, then EPERM is fine, turn this * into a success. Note that EPERM is also returned if we * already are the owner of the TTY. */ break; if (flags != ACQUIRE_TERMINAL_WAIT) /* If we are in TRY or FORCE mode, then propagate EPERM as EPERM */ return r; assert(notify >= 0); assert(wd >= 0); for (;;) { union inotify_event_buffer buffer; struct inotify_event *e; ssize_t l; if (timeout != USEC_INFINITY) { usec_t n; assert(ts != USEC_INFINITY); n = now(CLOCK_MONOTONIC); if (ts + timeout < n) return -ETIMEDOUT; r = fd_wait_for_event(notify, POLLIN, ts + timeout - n); if (r < 0) return r; if (r == 0) return -ETIMEDOUT; } l = read(notify, &buffer, sizeof(buffer)); if (l < 0) { if (IN_SET(errno, EINTR, EAGAIN)) continue; return -errno; } FOREACH_INOTIFY_EVENT(e, buffer, l) { if (e->mask & IN_Q_OVERFLOW) /* If we hit an inotify queue overflow, simply check if the terminal is up for grabs now. */ break; if (e->wd != wd || !(e->mask & IN_CLOSE)) /* Safety checks */ return -EIO; } break; } /* We close the tty fd here since if the old session ended our handle will be dead. It's important that * we do this after sleeping, so that we don't enter an endless loop. */ fd = safe_close(fd); } return TAKE_FD(fd); } int release_terminal(void) { static const struct sigaction sa_new = { .sa_handler = SIG_IGN, .sa_flags = SA_RESTART, }; _cleanup_close_ int fd = -1; struct sigaction sa_old; int r; fd = open("/dev/tty", O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK); if (fd < 0) return -errno; /* Temporarily ignore SIGHUP, so that we don't get SIGHUP'ed * by our own TIOCNOTTY */ assert_se(sigaction(SIGHUP, &sa_new, &sa_old) == 0); r = ioctl(fd, TIOCNOTTY) < 0 ? -errno : 0; assert_se(sigaction(SIGHUP, &sa_old, NULL) == 0); return r; } int terminal_vhangup_fd(int fd) { assert(fd >= 0); if (ioctl(fd, TIOCVHANGUP) < 0) return -errno; return 0; } int terminal_vhangup(const char *name) { _cleanup_close_ int fd; fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK); if (fd < 0) return fd; return terminal_vhangup_fd(fd); } int vt_disallocate(const char *name) { _cleanup_close_ int fd = -1; const char *e, *n; unsigned u; int r; /* Deallocate the VT if possible. If not possible * (i.e. because it is the active one), at least clear it * entirely (including the scrollback buffer) */ e = path_startswith(name, "/dev/"); if (!e) return -EINVAL; if (!tty_is_vc(name)) { /* So this is not a VT. I guess we cannot deallocate * it then. But let's at least clear the screen */ fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC); if (fd < 0) return fd; loop_write(fd, "\033[r" /* clear scrolling region */ "\033[H" /* move home */ "\033[2J", /* clear screen */ 10, false); return 0; } n = startswith(e, "tty"); if (!n) return -EINVAL; r = safe_atou(n, &u); if (r < 0) return r; if (u <= 0) return -EINVAL; /* Try to deallocate */ fd = open_terminal("/dev/tty0", O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK); if (fd < 0) return fd; r = ioctl(fd, VT_DISALLOCATE, u); fd = safe_close(fd); if (r >= 0) return 0; if (errno != EBUSY) return -errno; /* Couldn't deallocate, so let's clear it fully with * scrollback */ fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC); if (fd < 0) return fd; loop_write(fd, "\033[r" /* clear scrolling region */ "\033[H" /* move home */ "\033[3J", /* clear screen including scrollback, requires Linux 2.6.40 */ 10, false); return 0; } int make_console_stdio(void) { int fd, r; /* Make /dev/console the controlling terminal and stdin/stdout/stderr */ fd = acquire_terminal("/dev/console", ACQUIRE_TERMINAL_FORCE|ACQUIRE_TERMINAL_PERMISSIVE, USEC_INFINITY); if (fd < 0) return log_error_errno(fd, "Failed to acquire terminal: %m"); r = reset_terminal_fd(fd, true); if (r < 0) log_warning_errno(r, "Failed to reset terminal, ignoring: %m"); r = rearrange_stdio(fd, fd, fd); /* This invalidates 'fd' both on success and on failure. */ if (r < 0) return log_error_errno(r, "Failed to make terminal stdin/stdout/stderr: %m"); reset_terminal_feature_caches(); return 0; } bool tty_is_vc(const char *tty) { assert(tty); return vtnr_from_tty(tty) >= 0; } bool tty_is_console(const char *tty) { assert(tty); return streq(skip_dev_prefix(tty), "console"); } int vtnr_from_tty(const char *tty) { int i, r; assert(tty); tty = skip_dev_prefix(tty); if (!startswith(tty, "tty") ) return -EINVAL; if (tty[3] < '0' || tty[3] > '9') return -EINVAL; r = safe_atoi(tty+3, &i); if (r < 0) return r; if (i < 0 || i > 63) return -EINVAL; return i; } int resolve_dev_console(char **ret) { _cleanup_free_ char *active = NULL; char *tty; int r; assert(ret); /* Resolve where /dev/console is pointing to, if /sys is actually ours (i.e. not read-only-mounted which is a * sign for container setups) */ if (path_is_read_only_fs("/sys") > 0) return -ENOMEDIUM; r = read_one_line_file("/sys/class/tty/console/active", &active); if (r < 0) return r; /* If multiple log outputs are configured the last one is what /dev/console points to */ tty = strrchr(active, ' '); if (tty) tty++; else tty = active; if (streq(tty, "tty0")) { active = mfree(active); /* Get the active VC (e.g. tty1) */ r = read_one_line_file("/sys/class/tty/tty0/active", &active); if (r < 0) return r; tty = active; } if (tty == active) *ret = TAKE_PTR(active); else { char *tmp; tmp = strdup(tty); if (!tmp) return -ENOMEM; *ret = tmp; } return 0; } int get_kernel_consoles(char ***ret) { _cleanup_strv_free_ char **l = NULL; _cleanup_free_ char *line = NULL; const char *p; int r; assert(ret); /* If /sys is mounted read-only this means we are running in some kind of container environment. In that * case /sys would reflect the host system, not us, hence ignore the data we can read from it. */ if (path_is_read_only_fs("/sys") > 0) goto fallback; r = read_one_line_file("/sys/class/tty/console/active", &line); if (r < 0) return r; p = line; for (;;) { _cleanup_free_ char *tty = NULL; char *path; r = extract_first_word(&p, &tty, NULL, 0); if (r < 0) return r; if (r == 0) break; if (streq(tty, "tty0")) { tty = mfree(tty); r = read_one_line_file("/sys/class/tty/tty0/active", &tty); if (r < 0) return r; } path = strappend("/dev/", tty); if (!path) return -ENOMEM; if (access(path, F_OK) < 0) { log_debug_errno(errno, "Console device %s is not accessible, skipping: %m", path); free(path); continue; } r = strv_consume(&l, path); if (r < 0) return r; } if (strv_isempty(l)) { log_debug("No devices found for system console"); goto fallback; } *ret = TAKE_PTR(l); return 0; fallback: r = strv_extend(&l, "/dev/console"); if (r < 0) return r; *ret = TAKE_PTR(l); return 0; } bool tty_is_vc_resolve(const char *tty) { _cleanup_free_ char *resolved = NULL; assert(tty); tty = skip_dev_prefix(tty); if (streq(tty, "console")) { if (resolve_dev_console(&resolved) < 0) return false; tty = resolved; } return tty_is_vc(tty); } const char *default_term_for_tty(const char *tty) { return tty && tty_is_vc_resolve(tty) ? "linux" : "vt220"; } int fd_columns(int fd) { struct winsize ws = {}; if (ioctl(fd, TIOCGWINSZ, &ws) < 0) return -errno; if (ws.ws_col <= 0) return -EIO; return ws.ws_col; } unsigned columns(void) { const char *e; int c; if (cached_columns > 0) return cached_columns; c = 0; e = getenv("COLUMNS"); if (e) (void) safe_atoi(e, &c); if (c <= 0 || c > USHRT_MAX) { c = fd_columns(STDOUT_FILENO); if (c <= 0) c = 80; } cached_columns = c; return cached_columns; } int fd_lines(int fd) { struct winsize ws = {}; if (ioctl(fd, TIOCGWINSZ, &ws) < 0) return -errno; if (ws.ws_row <= 0) return -EIO; return ws.ws_row; } unsigned lines(void) { const char *e; int l; if (cached_lines > 0) return cached_lines; l = 0; e = getenv("LINES"); if (e) (void) safe_atoi(e, &l); if (l <= 0 || l > USHRT_MAX) { l = fd_lines(STDOUT_FILENO); if (l <= 0) l = 24; } cached_lines = l; return cached_lines; } /* intended to be used as a SIGWINCH sighandler */ void columns_lines_cache_reset(int signum) { cached_columns = 0; cached_lines = 0; } void reset_terminal_feature_caches(void) { cached_columns = 0; cached_lines = 0; cached_colors_enabled = -1; cached_underline_enabled = -1; cached_on_tty = -1; } bool on_tty(void) { /* We check both stdout and stderr, so that situations where pipes on the shell are used are reliably * recognized, regardless if only the output or the errors are piped to some place. Since on_tty() is generally * used to default to a safer, non-interactive, non-color mode of operation it's probably good to be defensive * here, and check for both. Note that we don't check for STDIN_FILENO, because it should fine to use fancy * terminal functionality when outputting stuff, even if the input is piped to us. */ if (cached_on_tty < 0) cached_on_tty = isatty(STDOUT_FILENO) > 0 && isatty(STDERR_FILENO) > 0; return cached_on_tty; } int getttyname_malloc(int fd, char **ret) { size_t l = 100; int r; assert(fd >= 0); assert(ret); for (;;) { char path[l]; r = ttyname_r(fd, path, sizeof(path)); if (r == 0) { char *c; c = strdup(skip_dev_prefix(path)); if (!c) return -ENOMEM; *ret = c; return 0; } if (r != ERANGE) return -r; l *= 2; } return 0; } int getttyname_harder(int fd, char **r) { int k; char *s = NULL; k = getttyname_malloc(fd, &s); if (k < 0) return k; if (streq(s, "tty")) { free(s); return get_ctty(0, NULL, r); } *r = s; return 0; } int get_ctty_devnr(pid_t pid, dev_t *d) { int r; _cleanup_free_ char *line = NULL; const char *p; unsigned long ttynr; assert(pid >= 0); p = procfs_file_alloca(pid, "stat"); r = read_one_line_file(p, &line); if (r < 0) return r; p = strrchr(line, ')'); if (!p) return -EIO; p++; if (sscanf(p, " " "%*c " /* state */ "%*d " /* ppid */ "%*d " /* pgrp */ "%*d " /* session */ "%lu ", /* ttynr */ &ttynr) != 1) return -EIO; if (major(ttynr) == 0 && minor(ttynr) == 0) return -ENXIO; if (d) *d = (dev_t) ttynr; return 0; } int get_ctty(pid_t pid, dev_t *ret_devnr, char **ret) { _cleanup_free_ char *fn = NULL, *b = NULL; dev_t devnr; int r; r = get_ctty_devnr(pid, &devnr); if (r < 0) return r; r = device_path_make_canonical(S_IFCHR, devnr, &fn); if (r < 0) { if (r != -ENOENT) /* No symlink for this in /dev/char/? */ return r; if (major(devnr) == 136) { /* This is an ugly hack: PTY devices are not listed in /dev/char/, as they don't follow the * Linux device model. This means we have no nice way to match them up against their actual * device node. Let's hence do the check by the fixed, assigned major number. Normally we try * to avoid such fixed major/minor matches, but there appears to nother nice way to handle * this. */ if (asprintf(&b, "pts/%u", minor(devnr)) < 0) return -ENOMEM; } else { /* Probably something similar to the ptys which have no symlink in /dev/char/. Let's return * something vaguely useful. */ r = device_path_make_major_minor(S_IFCHR, devnr, &fn); if (r < 0) return r; } } if (!b) { const char *w; w = path_startswith(fn, "/dev/"); if (w) { b = strdup(w); if (!b) return -ENOMEM; } else b = TAKE_PTR(fn); } if (ret) *ret = TAKE_PTR(b); if (ret_devnr) *ret_devnr = devnr; return 0; } int ptsname_malloc(int fd, char **ret) { size_t l = 100; assert(fd >= 0); assert(ret); for (;;) { char *c; c = new(char, l); if (!c) return -ENOMEM; if (ptsname_r(fd, c, l) == 0) { *ret = c; return 0; } if (errno != ERANGE) { free(c); return -errno; } free(c); l *= 2; } } int ptsname_namespace(int pty, char **ret) { int no = -1, r; /* Like ptsname(), but doesn't assume that the path is * accessible in the local namespace. */ r = ioctl(pty, TIOCGPTN, &no); if (r < 0) return -errno; if (no < 0) return -EIO; if (asprintf(ret, "/dev/pts/%i", no) < 0) return -ENOMEM; return 0; } int openpt_in_namespace(pid_t pid, int flags) { _cleanup_close_ int pidnsfd = -1, mntnsfd = -1, usernsfd = -1, rootfd = -1; _cleanup_close_pair_ int pair[2] = { -1, -1 }; pid_t child; int r; assert(pid > 0); r = namespace_open(pid, &pidnsfd, &mntnsfd, NULL, &usernsfd, &rootfd); if (r < 0) return r; if (socketpair(AF_UNIX, SOCK_DGRAM, 0, pair) < 0) return -errno; r = namespace_fork("(sd-openptns)", "(sd-openpt)", NULL, 0, FORK_RESET_SIGNALS|FORK_DEATHSIG, pidnsfd, mntnsfd, -1, usernsfd, rootfd, &child); if (r < 0) return r; if (r == 0) { int master; pair[0] = safe_close(pair[0]); master = posix_openpt(flags|O_NOCTTY|O_CLOEXEC); if (master < 0) _exit(EXIT_FAILURE); if (unlockpt(master) < 0) _exit(EXIT_FAILURE); if (send_one_fd(pair[1], master, 0) < 0) _exit(EXIT_FAILURE); _exit(EXIT_SUCCESS); } pair[1] = safe_close(pair[1]); r = wait_for_terminate_and_check("(sd-openptns)", child, 0); if (r < 0) return r; if (r != EXIT_SUCCESS) return -EIO; return receive_one_fd(pair[0], 0); } int open_terminal_in_namespace(pid_t pid, const char *name, int mode) { _cleanup_close_ int pidnsfd = -1, mntnsfd = -1, usernsfd = -1, rootfd = -1; _cleanup_close_pair_ int pair[2] = { -1, -1 }; pid_t child; int r; r = namespace_open(pid, &pidnsfd, &mntnsfd, NULL, &usernsfd, &rootfd); if (r < 0) return r; if (socketpair(AF_UNIX, SOCK_DGRAM, 0, pair) < 0) return -errno; r = namespace_fork("(sd-terminalns)", "(sd-terminal)", NULL, 0, FORK_RESET_SIGNALS|FORK_DEATHSIG, pidnsfd, mntnsfd, -1, usernsfd, rootfd, &child); if (r < 0) return r; if (r == 0) { int master; pair[0] = safe_close(pair[0]); master = open_terminal(name, mode|O_NOCTTY|O_CLOEXEC); if (master < 0) _exit(EXIT_FAILURE); if (send_one_fd(pair[1], master, 0) < 0) _exit(EXIT_FAILURE); _exit(EXIT_SUCCESS); } pair[1] = safe_close(pair[1]); r = wait_for_terminate_and_check("(sd-terminalns)", child, 0); if (r < 0) return r; if (r != EXIT_SUCCESS) return -EIO; return receive_one_fd(pair[0], 0); } static bool getenv_terminal_is_dumb(void) { const char *e; e = getenv("TERM"); if (!e) return true; return streq(e, "dumb"); } bool terminal_is_dumb(void) { if (!on_tty()) return true; return getenv_terminal_is_dumb(); } bool colors_enabled(void) { /* Returns true if colors are considered supported on our stdout. For that we check $SYSTEMD_COLORS first * (which is the explicit way to turn colors on/off). If that didn't work we turn colors off unless we are on a * TTY. And if we are on a TTY we turn it off if $TERM is set to "dumb". There's one special tweak though: if * we are PID 1 then we do not check whether we are connected to a TTY, because we don't keep /dev/console open * continously due to fear of SAK, and hence things are a bit weird. */ if (cached_colors_enabled < 0) { int val; val = getenv_bool("SYSTEMD_COLORS"); if (val >= 0) cached_colors_enabled = val; else if (getpid_cached() == 1) /* PID1 outputs to the console without holding it open all the time */ cached_colors_enabled = !getenv_terminal_is_dumb(); else cached_colors_enabled = !terminal_is_dumb(); } return cached_colors_enabled; } bool dev_console_colors_enabled(void) { _cleanup_free_ char *s = NULL; int b; /* Returns true if we assume that color is supported on /dev/console. * * For that we first check if we explicitly got told to use colors or not, by checking $SYSTEMD_COLORS. If that * isn't set we check whether PID 1 has $TERM set, and if not, whether TERM is set on the kernel command * line. If we find $TERM set we assume color if it's not set to "dumb", similarly to how regular * colors_enabled() operates. */ b = getenv_bool("SYSTEMD_COLORS"); if (b >= 0) return b; if (getenv_for_pid(1, "TERM", &s) <= 0) (void) proc_cmdline_get_key("TERM", 0, &s); return !streq_ptr(s, "dumb"); } bool underline_enabled(void) { if (cached_underline_enabled < 0) { /* The Linux console doesn't support underlining, turn it off, but only there. */ if (colors_enabled()) cached_underline_enabled = !streq_ptr(getenv("TERM"), "linux"); else cached_underline_enabled = false; } return cached_underline_enabled; } int vt_default_utf8(void) { _cleanup_free_ char *b = NULL; int r; /* Read the default VT UTF8 setting from the kernel */ r = read_one_line_file("/sys/module/vt/parameters/default_utf8", &b); if (r < 0) return r; return parse_boolean(b); } int vt_reset_keyboard(int fd) { int kb; /* If we can't read the default, then default to unicode. It's 2017 after all. */ kb = vt_default_utf8() != 0 ? K_UNICODE : K_XLATE; if (ioctl(fd, KDSKBMODE, kb) < 0) return -errno; return 0; } int vt_restore(int fd) { static const struct vt_mode mode = { .mode = VT_AUTO, }; int r, q = 0; r = ioctl(fd, KDSETMODE, KD_TEXT); if (r < 0) q = log_debug_errno(errno, "Failed to set VT in text mode, ignoring: %m"); r = vt_reset_keyboard(fd); if (r < 0) { log_debug_errno(r, "Failed to reset keyboard mode, ignoring: %m"); if (q >= 0) q = r; } r = ioctl(fd, VT_SETMODE, &mode); if (r < 0) { log_debug_errno(errno, "Failed to set VT_AUTO mode, ignoring: %m"); if (q >= 0) q = -errno; } r = fchown(fd, 0, (gid_t) -1); if (r < 0) { log_debug_errno(errno, "Failed to chown VT, ignoring: %m"); if (q >= 0) q = -errno; } return q; } int vt_release(int fd, bool restore) { assert(fd >= 0); /* This function releases the VT by acknowledging the VT-switch signal * sent by the kernel and optionally reset the VT in text and auto * VT-switching modes. */ if (ioctl(fd, VT_RELDISP, 1) < 0) return -errno; if (restore) return vt_restore(fd); return 0; }