/*** This file is part of systemd. Copyright 2010 Lennart Poettering systemd is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. systemd is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with systemd; If not, see <http://www.gnu.org/licenses/>. ***/ #include <sys/ioctl.h> #include <sys/types.h> #include <sys/stat.h> #include <termios.h> #include <unistd.h> #include <fcntl.h> #include <signal.h> #include <time.h> #include <assert.h> #include <poll.h> #include <linux/vt.h> #include <linux/tiocl.h> #include <linux/kd.h> #include "terminal-util.h" #include "time-util.h" #include "process-util.h" #include "util.h" #include "fileio.h" #include "path-util.h" static volatile unsigned cached_columns = 0; static volatile unsigned cached_lines = 0; int chvt(int vt) { _cleanup_close_ int fd; fd = open_terminal("/dev/tty0", O_RDWR|O_NOCTTY|O_CLOEXEC); 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) { struct termios old_termios, new_termios; char c, line[LINE_MAX]; assert(f); assert(ret); if (tcgetattr(fileno(f), &old_termios) >= 0) { 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) { size_t k; if (t != USEC_INFINITY) { if (fd_wait_for_event(fileno(f), POLLIN, t) <= 0) { tcsetattr(fileno(f), TCSADRAIN, &old_termios); return -ETIMEDOUT; } } k = fread(&c, 1, 1, f); tcsetattr(fileno(f), TCSADRAIN, &old_termios); if (k <= 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; } errno = 0; if (!fgets(line, sizeof(line), f)) return errno ? -errno : -EIO; truncate_nl(line); if (strlen(line) != 1) return -EBADMSG; if (need_nl) *need_nl = false; *ret = line[0]; return 0; } int ask_char(char *ret, const char *replies, const char *text, ...) { int r; assert(ret); assert(replies); assert(text); for (;;) { va_list ap; char c; bool need_nl = true; if (on_tty()) fputs(ANSI_HIGHLIGHT_ON, stdout); va_start(ap, text); vprintf(text, ap); va_end(ap); if (on_tty()) fputs(ANSI_HIGHLIGHT_OFF, stdout); fflush(stdout); r = read_one_char(stdin, &c, USEC_INFINITY, &need_nl); if (r < 0) { 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, ...) { assert(ret); assert(text); for (;;) { char line[LINE_MAX]; va_list ap; if (on_tty()) fputs(ANSI_HIGHLIGHT_ON, stdout); va_start(ap, text); vprintf(text, ap); va_end(ap); if (on_tty()) fputs(ANSI_HIGHLIGHT_OFF, stdout); fflush(stdout); errno = 0; if (!fgets(line, sizeof(line), stdin)) return errno ? -errno : -EIO; if (!endswith(line, "\n")) putchar('\n'); else { char *s; if (isempty(line)) continue; truncate_nl(line); s = strdup(line); if (!s) return -ENOMEM; *ret = s; 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 */ ioctl(fd, TIOCNXCL); /* Switch to text mode */ if (switch_to_text) ioctl(fd, KDSETMODE, KD_TEXT); /* Enable console unicode mode */ ioctl(fd, KDSKBMODE, K_UNICODE); 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 */ tcflush(fd, TCIOFLUSH); return r; } int reset_terminal(const char *name) { _cleanup_close_ int fd = -1; fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC); if (fd < 0) return fd; return reset_terminal_fd(fd, true); } int open_terminal(const char *name, int mode) { int fd, r; unsigned c = 0; /* * 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 */ assert(!(mode & O_CREAT)); 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++; } r = isatty(fd); if (r < 0) { safe_close(fd); return -errno; } if (!r) { safe_close(fd); return -ENOTTY; } return fd; } int acquire_terminal( const char *name, bool fail, bool force, bool ignore_tiocstty_eperm, usec_t timeout) { int fd = -1, notify = -1, r = 0, wd = -1; usec_t ts = 0; assert(name); /* 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 not configure any service * on the same tty as an untrusted user this should not be a * problem. (Which he probably should not do anyway.) */ if (timeout != USEC_INFINITY) ts = now(CLOCK_MONOTONIC); if (!fail && !force) { notify = inotify_init1(IN_CLOEXEC | (timeout != USEC_INFINITY ? IN_NONBLOCK : 0)); if (notify < 0) { r = -errno; goto fail; } wd = inotify_add_watch(notify, name, IN_CLOSE); if (wd < 0) { r = -errno; goto fail; } } 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) goto fail; } /* 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 */ if (ioctl(fd, TIOCSCTTY, force) < 0) r = -errno; assert_se(sigaction(SIGHUP, &sa_old, NULL) == 0); /* Sometimes it makes sense to ignore TIOCSCTTY * returning EPERM, i.e. when very likely we already * are have this controlling terminal. */ if (r < 0 && r == -EPERM && ignore_tiocstty_eperm) r = 0; if (r < 0 && (force || fail || r != -EPERM)) { goto fail; } if (r >= 0) break; assert(!fail); assert(!force); assert(notify >= 0); for (;;) { union inotify_event_buffer buffer; struct inotify_event *e; ssize_t l; if (timeout != USEC_INFINITY) { usec_t n; n = now(CLOCK_MONOTONIC); if (ts + timeout < n) { r = -ETIMEDOUT; goto fail; } r = fd_wait_for_event(fd, POLLIN, ts + timeout - n); if (r < 0) goto fail; if (r == 0) { r = -ETIMEDOUT; goto fail; } } l = read(notify, &buffer, sizeof(buffer)); if (l < 0) { if (errno == EINTR || errno == EAGAIN) continue; r = -errno; goto fail; } FOREACH_INOTIFY_EVENT(e, buffer, l) { if (e->wd != wd || !(e->mask & IN_CLOSE)) { r = -EIO; goto fail; } } 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); } safe_close(notify); r = reset_terminal_fd(fd, true); if (r < 0) log_warning_errno(r, "Failed to reset terminal: %m"); return fd; fail: safe_close(fd); safe_close(notify); return r; } 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 = 0; fd = open("/dev/tty", O_RDWR|O_NOCTTY|O_NDELAY|O_CLOEXEC); 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); if (ioctl(fd, TIOCNOTTY) < 0) r = -errno; 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); if (fd < 0) return fd; return terminal_vhangup_fd(fd); } int vt_disallocate(const char *name) { int fd, r; unsigned u; /* 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) */ if (!startswith(name, "/dev/")) 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); safe_close(fd); return 0; } if (!startswith(name, "/dev/tty")) return -EINVAL; r = safe_atou(name+8, &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); if (fd < 0) return fd; r = ioctl(fd, VT_DISALLOCATE, u); 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); safe_close(fd); return 0; } void warn_melody(void) { _cleanup_close_ int fd = -1; fd = open("/dev/console", O_WRONLY|O_CLOEXEC|O_NOCTTY); if (fd < 0) return; /* Yeah, this is synchronous. Kinda sucks. But well... */ ioctl(fd, KIOCSOUND, (int)(1193180/440)); usleep(125*USEC_PER_MSEC); ioctl(fd, KIOCSOUND, (int)(1193180/220)); usleep(125*USEC_PER_MSEC); ioctl(fd, KIOCSOUND, (int)(1193180/220)); usleep(125*USEC_PER_MSEC); ioctl(fd, KIOCSOUND, 0); } int make_console_stdio(void) { int fd, r; /* Make /dev/console the controlling terminal and stdin/stdout/stderr */ fd = acquire_terminal("/dev/console", false, true, true, USEC_INFINITY); if (fd < 0) return log_error_errno(fd, "Failed to acquire terminal: %m"); r = make_stdio(fd); if (r < 0) return log_error_errno(r, "Failed to duplicate terminal fd: %m"); return 0; } int status_vprintf(const char *status, bool ellipse, bool ephemeral, const char *format, va_list ap) { static const char status_indent[] = " "; /* "[" STATUS "] " */ _cleanup_free_ char *s = NULL; _cleanup_close_ int fd = -1; struct iovec iovec[6] = {}; int n = 0; static bool prev_ephemeral; assert(format); /* This is independent of logging, as status messages are * optional and go exclusively to the console. */ if (vasprintf(&s, format, ap) < 0) return log_oom(); fd = open_terminal("/dev/console", O_WRONLY|O_NOCTTY|O_CLOEXEC); if (fd < 0) return fd; if (ellipse) { char *e; size_t emax, sl; int c; c = fd_columns(fd); if (c <= 0) c = 80; sl = status ? sizeof(status_indent)-1 : 0; emax = c - sl - 1; if (emax < 3) emax = 3; e = ellipsize(s, emax, 50); if (e) { free(s); s = e; } } if (prev_ephemeral) IOVEC_SET_STRING(iovec[n++], "\r" ANSI_ERASE_TO_END_OF_LINE); prev_ephemeral = ephemeral; if (status) { if (!isempty(status)) { IOVEC_SET_STRING(iovec[n++], "["); IOVEC_SET_STRING(iovec[n++], status); IOVEC_SET_STRING(iovec[n++], "] "); } else IOVEC_SET_STRING(iovec[n++], status_indent); } IOVEC_SET_STRING(iovec[n++], s); if (!ephemeral) IOVEC_SET_STRING(iovec[n++], "\n"); if (writev(fd, iovec, n) < 0) return -errno; return 0; } int status_printf(const char *status, bool ellipse, bool ephemeral, const char *format, ...) { va_list ap; int r; assert(format); va_start(ap, format); r = status_vprintf(status, ellipse, ephemeral, format, ap); va_end(ap); return r; } bool tty_is_vc(const char *tty) { assert(tty); return vtnr_from_tty(tty) >= 0; } bool tty_is_console(const char *tty) { assert(tty); if (startswith(tty, "/dev/")) tty += 5; return streq(tty, "console"); } int vtnr_from_tty(const char *tty) { int i, r; assert(tty); if (startswith(tty, "/dev/")) tty += 5; 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; } char *resolve_dev_console(char **active) { char *tty; /* 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 NULL; if (read_one_line_file("/sys/class/tty/console/active", active) < 0) return NULL; /* 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")) { char *tmp; /* Get the active VC (e.g. tty1) */ if (read_one_line_file("/sys/class/tty/tty0/active", &tmp) >= 0) { free(*active); tty = *active = tmp; } } return tty; } bool tty_is_vc_resolve(const char *tty) { _cleanup_free_ char *active = NULL; assert(tty); if (startswith(tty, "/dev/")) tty += 5; if (streq(tty, "console")) { tty = resolve_dev_console(&active); if (!tty) return false; } return tty_is_vc(tty); } const char *default_term_for_tty(const char *tty) { assert(tty); return tty_is_vc_resolve(tty) ? "TERM=linux" : "TERM=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 (_likely_(cached_columns > 0)) return cached_columns; c = 0; e = getenv("COLUMNS"); if (e) (void) safe_atoi(e, &c); if (c <= 0) 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 (_likely_(cached_lines > 0)) return cached_lines; l = 0; e = getenv("LINES"); if (e) (void) safe_atoi(e, &l); if (l <= 0) 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; } bool on_tty(void) { static int cached_on_tty = -1; if (_unlikely_(cached_on_tty < 0)) cached_on_tty = isatty(STDOUT_FILENO) > 0; return cached_on_tty; } int make_stdio(int fd) { int r, s, t; assert(fd >= 0); r = dup2(fd, STDIN_FILENO); s = dup2(fd, STDOUT_FILENO); t = dup2(fd, STDERR_FILENO); if (fd >= 3) safe_close(fd); if (r < 0 || s < 0 || t < 0) return -errno; /* Explicitly unset O_CLOEXEC, since if fd was < 3, then * dup2() was a NOP and the bit hence possibly set. */ fd_cloexec(STDIN_FILENO, false); fd_cloexec(STDOUT_FILENO, false); fd_cloexec(STDERR_FILENO, false); return 0; } int make_null_stdio(void) { int null_fd; null_fd = open("/dev/null", O_RDWR|O_NOCTTY); if (null_fd < 0) return -errno; return make_stdio(null_fd); } 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) { const char *p; char *c; p = startswith(path, "/dev/"); c = strdup(p ?: 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 *_devnr, char **r) { char fn[sizeof("/dev/char/")-1 + 2*DECIMAL_STR_MAX(unsigned) + 1 + 1], *b = NULL; _cleanup_free_ char *s = NULL; const char *p; dev_t devnr; int k; assert(r); k = get_ctty_devnr(pid, &devnr); if (k < 0) return k; sprintf(fn, "/dev/char/%u:%u", major(devnr), minor(devnr)); k = readlink_malloc(fn, &s); if (k < 0) { if (k != -ENOENT) return k; /* This is an ugly hack */ if (major(devnr) == 136) { if (asprintf(&b, "pts/%u", minor(devnr)) < 0) return -ENOMEM; } else { /* Probably something like the ptys which have no * symlink in /dev/char. Let's return something * vaguely useful. */ b = strdup(fn + 5); if (!b) return -ENOMEM; } } else { if (startswith(s, "/dev/")) p = s + 5; else if (startswith(s, "../")) p = s + 3; else p = s; b = strdup(p); if (!b) return -ENOMEM; } *r = b; if (_devnr) *_devnr = devnr; return 0; }