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systemd/src/basic/terminal-util.c
Daan De Meyer f57705d67d terminal-util: Enable line wrapping in reset_terminal_fd() 
The qemu seabios firmware disables serial console line wrapping. Let's
make sure we re-enable it again when we reset a terminal to some sane
defaults.

To avoid potentially blocking on writing to the terminal, we put it
in nonblocking mode and add a timeout of 50ms.
2024-04-22 15:28:26 +02:00

1797 lines
56 KiB
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/* SPDX-License-Identifier: LGPL-2.1-or-later */
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <linux/kd.h>
#include <linux/tiocl.h>
#include <linux/vt.h>
#include <poll.h>
#include <signal.h>
#include <stdarg.h>
#include <stddef.h>
#include <stdlib.h>
#include <sys/inotify.h>
#include <sys/ioctl.h>
#include <sys/sysmacros.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/utsname.h>
#include <termios.h>
#include <unistd.h>
#include "alloc-util.h"
#include "constants.h"
#include "devnum-util.h"
#include "env-util.h"
#include "fd-util.h"
#include "fileio.h"
#include "fs-util.h"
#include "hexdecoct.h"
#include "inotify-util.h"
#include "io-util.h"
#include "log.h"
#include "macro.h"
#include "namespace-util.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 "stdio-util.h"
#include "string-util.h"
#include "strv.h"
#include "terminal-util.h"
#include "time-util.h"
#include "user-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_on_dev_null = -1;
static volatile int cached_color_mode = _COLOR_INVALID;
static volatile int cached_underline_enabled = -1;
bool isatty_safe(int fd) {
assert(fd >= 0);
if (isatty(fd))
return true;
/* Be resilient if we're working on stdio, since they're set up by parent process. */
assert(errno != EBADF || IN_SET(fd, STDIN_FILENO, STDOUT_FILENO, STDERR_FILENO));
return false;
}
int chvt(int vt) {
_cleanup_close_ int fd = -EBADF;
/* 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];
}
return RET_NERRNO(ioctl(fd, VT_ACTIVATE, vt));
}
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, fd;
assert(f);
assert(ret);
/* If this is a terminal, then switch canonical mode off, so that we can read a single
* character. (Note that fmemopen() streams do not have an fd associated with them, let's handle that
* nicely.) */
fd = fileno(f);
if (fd >= 0 && tcgetattr(fd, &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(fd, TCSADRAIN, &new_termios) >= 0) {
char c;
if (t != USEC_INFINITY) {
if (fd_wait_for_event(fd, POLLIN, t) <= 0) {
(void) tcsetattr(fd, TCSADRAIN, &old_termios);
return -ETIMEDOUT;
}
}
r = safe_fgetc(f, &c);
(void) tcsetattr(fd, 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 && fd > 0) {
/* Let's wait the specified amount of time for input. When we have no fd we skip this, under
* the assumption that this is an fmemopen() stream or so where waiting doesn't make sense
* anyway, as the data is either already in the stream or cannot possible be placed there
* while we access the stream */
if (fd_wait_for_event(fd, 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;
fputs(ansi_highlight(), stdout);
putchar('\r');
va_start(ap, fmt);
vprintf(fmt, ap);
va_end(ap);
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, ...) {
_cleanup_free_ char *line = NULL;
va_list ap;
int r;
assert(ret);
assert(text);
fputs(ansi_highlight(), stdout);
va_start(ap, text);
vprintf(text, ap);
va_end(ap);
fputs(ansi_normal(), stdout);
fflush(stdout);
r = read_line(stdin, LONG_LINE_MAX, &line);
if (r < 0)
return r;
if (r == 0)
return -EIO;
*ret = TAKE_PTR(line);
return 0;
}
int reset_terminal_fd(int fd, bool switch_to_text) {
struct termios termios;
int r;
/* Set terminal to some sane defaults */
assert(fd >= 0);
if (!isatty_safe(fd))
return log_debug_errno(errno, "Asked to reset a terminal that actually isn't a terminal: %m");
/* 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 */
if (ioctl(fd, TIOCNXCL) < 0)
log_debug_errno(errno, "TIOCNXCL ioctl failed on TTY, ignoring: %m");
/* Switch to text mode */
if (switch_to_text)
if (ioctl(fd, KDSETMODE, KD_TEXT) < 0)
log_debug_errno(errno, "KDSETMODE ioctl for switching to text mode failed on TTY, ignoring: %m");
/* Set default keyboard mode */
r = vt_reset_keyboard(fd);
if (r < 0)
log_debug_errno(r, "Failed to reset VT keyboard, ignoring: %m");
if (tcgetattr(fd, &termios) < 0) {
r = log_debug_errno(errno, "Failed to get terminal parameters: %m");
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 | OPOST;
termios.c_cflag |= CREAD;
termios.c_lflag = ISIG | ICANON | IEXTEN | ECHO | ECHOE | ECHOK | ECHOCTL | 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;
r = RET_NERRNO(tcsetattr(fd, TCSANOW, &termios));
if (r < 0) {
log_debug_errno(r, "Failed to set terminal parameters: %m");
goto finish;
}
if (!terminal_is_dumb()) {
r = fd_nonblock(fd, true);
if (r < 0) {
log_debug_errno(r, "Failed to set terminal to non-blocking mode: %m");
goto finish;
}
/* Enable line wrapping. */
(void) loop_write_full(fd, "\033[?7h", SIZE_MAX, 50 * USEC_PER_MSEC);
if (r > 0) {
r = fd_nonblock(fd, false);
if (r < 0) {
log_debug_errno(r, "Failed to set terminal back to blocking mode: %m");
goto finish;
}
}
}
finish:
/* Just in case, flush all crap out */
(void) tcflush(fd, TCIOFLUSH);
return r;
}
int reset_terminal(const char *name) {
_cleanup_close_ int fd = -EBADF;
/* 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) {
_cleanup_close_ int fd = -EBADF;
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
*/
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;
(void) usleep_safe(50 * USEC_PER_MSEC);
c++;
}
if (!isatty_safe(fd))
return negative_errno();
return TAKE_FD(fd);
}
int acquire_terminal(
const char *name,
AcquireTerminalFlags flags,
usec_t timeout) {
_cleanup_close_ int notify = -EBADF, fd = -EBADF;
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 = RET_NERRNO(ioctl(fd, TIOCSCTTY, (flags & ~ACQUIRE_TERMINAL_PERMISSIVE) == ACQUIRE_TERMINAL_FORCE));
/* 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;
ssize_t l;
if (timeout != USEC_INFINITY) {
usec_t n;
assert(ts != USEC_INFINITY);
n = usec_sub_unsigned(now(CLOCK_MONOTONIC), ts);
if (n >= timeout)
return -ETIMEDOUT;
r = fd_wait_for_event(notify, POLLIN, usec_sub_unsigned(timeout, n));
if (r < 0)
return r;
if (r == 0)
return -ETIMEDOUT;
}
l = read(notify, &buffer, sizeof(buffer));
if (l < 0) {
if (ERRNO_IS_TRANSIENT(errno))
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 = -EBADF;
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 = RET_NERRNO(ioctl(fd, TIOCNOTTY));
assert_se(sigaction(SIGHUP, &sa_old, NULL) == 0);
return r;
}
int terminal_vhangup_fd(int fd) {
assert(fd >= 0);
return RET_NERRNO(ioctl(fd, TIOCVHANGUP));
}
int terminal_vhangup(const char *name) {
_cleanup_close_ int fd = -EBADF;
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) {
const char *e;
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)) {
_cleanup_close_ int fd = -EBADF;
unsigned u;
const char *n;
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);
if (r >= 0)
return 0;
if (errno != EBUSY)
return -errno;
}
/* So this is not a VT (in which case we cannot deallocate it),
* or we failed to deallocate. Let's at least clear the screen. */
_cleanup_close_ int fd2 = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC);
if (fd2 < 0)
return fd2;
(void) loop_write(fd2,
"\033[r" /* clear scrolling region */
"\033[H" /* move home */
"\033[3J", /* clear screen including scrollback, requires Linux 2.6.40 */
10);
return 0;
}
int make_console_stdio(void) {
int fd, r;
/* Make /dev/console the controlling terminal and stdin/stdout/stderr, if we can. If we can't use
* /dev/null instead. This is particularly useful if /dev/console is turned off, e.g. if console=null
* is specified on the kernel command line. */
fd = acquire_terminal("/dev/console", ACQUIRE_TERMINAL_FORCE|ACQUIRE_TERMINAL_PERMISSIVE, USEC_INFINITY);
if (fd < 0) {
log_warning_errno(fd, "Failed to acquire terminal, using /dev/null stdin/stdout/stderr instead: %m");
r = make_null_stdio();
if (r < 0)
return log_error_errno(r, "Failed to make /dev/null stdin/stdout/stderr: %m");
} else {
unsigned rows, cols;
r = reset_terminal_fd(fd, /* switch_to_text= */ true);
if (r < 0)
log_warning_errno(r, "Failed to reset terminal, ignoring: %m");
r = proc_cmdline_tty_size("/dev/console", &rows, &cols);
if (r < 0)
log_warning_errno(r, "Failed to get terminal size, ignoring: %m");
else {
r = terminal_set_size_fd(fd, NULL, rows, cols);
if (r < 0)
log_warning_errno(r, "Failed to set terminal size, 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 (!ascii_isdigit(tty[3]))
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)
return strdup_to(ret, tty);
*ret = TAKE_PTR(active);
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, *path = NULL;
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 = path_join("/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);
continue;
}
r = strv_consume(&l, TAKE_PTR(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 (fd < 0)
return -EBADF;
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 (fd < 0)
return -EBADF;
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;
}
int terminal_set_size_fd(int fd, const char *ident, unsigned rows, unsigned cols) {
struct winsize ws;
if (rows == UINT_MAX && cols == UINT_MAX)
return 0;
if (ioctl(fd, TIOCGWINSZ, &ws) < 0)
return log_debug_errno(errno,
"TIOCGWINSZ ioctl for getting %s size failed, not setting terminal size: %m",
ident ?: "TTY");
if (rows == UINT_MAX)
rows = ws.ws_row;
else if (rows > USHRT_MAX)
rows = USHRT_MAX;
if (cols == UINT_MAX)
cols = ws.ws_col;
else if (cols > USHRT_MAX)
cols = USHRT_MAX;
if (rows == ws.ws_row && cols == ws.ws_col)
return 0;
ws.ws_row = rows;
ws.ws_col = cols;
if (ioctl(fd, TIOCSWINSZ, &ws) < 0)
return log_debug_errno(errno, "TIOCSWINSZ ioctl for setting %s size failed: %m", ident ?: "TTY");
return 0;
}
int proc_cmdline_tty_size(const char *tty, unsigned *ret_rows, unsigned *ret_cols) {
_cleanup_free_ char *rowskey = NULL, *rowsvalue = NULL, *colskey = NULL, *colsvalue = NULL;
unsigned rows = UINT_MAX, cols = UINT_MAX;
int r;
assert(tty);
if (!ret_rows && !ret_cols)
return 0;
tty = skip_dev_prefix(tty);
if (!in_charset(tty, ALPHANUMERICAL))
return log_debug_errno(SYNTHETIC_ERRNO(EINVAL), "%s contains non-alphanumeric characters", tty);
rowskey = strjoin("systemd.tty.rows.", tty);
if (!rowskey)
return -ENOMEM;
colskey = strjoin("systemd.tty.columns.", tty);
if (!colskey)
return -ENOMEM;
r = proc_cmdline_get_key_many(/* flags = */ 0,
rowskey, &rowsvalue,
colskey, &colsvalue);
if (r < 0)
return log_debug_errno(r, "Failed to read TTY size of %s from kernel cmdline: %m", tty);
if (rowsvalue) {
r = safe_atou(rowsvalue, &rows);
if (r < 0)
return log_debug_errno(r, "Failed to parse %s=%s: %m", rowskey, rowsvalue);
}
if (colsvalue) {
r = safe_atou(colsvalue, &cols);
if (r < 0)
return log_debug_errno(r, "Failed to parse %s=%s: %m", colskey, colsvalue);
}
if (ret_rows)
*ret_rows = rows;
if (ret_cols)
*ret_cols = cols;
return 0;
}
/* 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_color_mode = _COLOR_INVALID;
cached_underline_enabled = -1;
cached_on_tty = -1;
cached_on_dev_null = -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) {
char path[PATH_MAX]; /* PATH_MAX is counted *with* the trailing NUL byte */
int r;
assert(fd >= 0);
assert(ret);
r = ttyname_r(fd, path, sizeof path); /* positive error */
assert(r >= 0);
if (r == ERANGE)
return -ENAMETOOLONG;
if (r > 0)
return -r;
return strdup_to(ret, skip_dev_prefix(path));
}
int getttyname_harder(int fd, char **ret) {
_cleanup_free_ char *s = NULL;
int r;
r = getttyname_malloc(fd, &s);
if (r < 0)
return r;
if (streq(s, "tty"))
return get_ctty(0, NULL, ret);
*ret = TAKE_PTR(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 (devnum_is_zero(ttynr))
return -ENXIO;
if (d)
*d = (dev_t) ttynr;
return 0;
}
int get_ctty(pid_t pid, dev_t *ret_devnr, char **ret) {
char pty[STRLEN("/dev/pts/") + DECIMAL_STR_MAX(dev_t) + 1];
_cleanup_free_ char *buf = NULL;
const char *fn = NULL, *w;
dev_t devnr;
int r;
r = get_ctty_devnr(pid, &devnr);
if (r < 0)
return r;
r = device_path_make_canonical(S_IFCHR, devnr, &buf);
if (r < 0) {
struct stat st;
if (r != -ENOENT) /* No symlink for this in /dev/char/? */
return r;
/* Maybe this is PTY? PTY devices are not listed in /dev/char/, as they don't follow the
* Linux device model and hence device_path_make_canonical() doesn't work for them. Let's
* assume this is a PTY for a moment, and check if the device node this would then map to in
* /dev/pts/ matches the one we are looking for. This way we don't have to hardcode the major
* number (which is 136 btw), but we still rely on the fact that PTY numbers map directly to
* the minor number of the pty. */
xsprintf(pty, "/dev/pts/%u", minor(devnr));
if (stat(pty, &st) < 0) {
if (errno != ENOENT)
return -errno;
} else if (S_ISCHR(st.st_mode) && devnr == st.st_rdev) /* Bingo! */
fn = pty;
if (!fn) {
/* Doesn't exist, or not a PTY? 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, &buf);
if (r < 0)
return r;
fn = buf;
}
} else
fn = buf;
w = path_startswith(fn, "/dev/");
if (!w)
return -EINVAL;
if (ret) {
r = strdup_to(ret, w);
if (r < 0)
return r;
}
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);
if (l > SIZE_MAX / 2)
return -ENOMEM;
l *= 2;
}
}
int openpt_allocate(int flags, char **ret_slave) {
_cleanup_close_ int fd = -EBADF;
_cleanup_free_ char *p = NULL;
int r;
fd = posix_openpt(flags|O_NOCTTY|O_CLOEXEC);
if (fd < 0)
return -errno;
if (ret_slave) {
r = ptsname_malloc(fd, &p);
if (r < 0)
return r;
if (!path_startswith(p, "/dev/pts/"))
return -EINVAL;
}
if (unlockpt(fd) < 0)
return -errno;
if (ret_slave)
*ret_slave = TAKE_PTR(p);
return TAKE_FD(fd);
}
static 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_allocate_in_namespace(pid_t pid, int flags, char **ret_slave) {
_cleanup_close_ int pidnsfd = -EBADF, mntnsfd = -EBADF, usernsfd = -EBADF, rootfd = -EBADF, fd = -EBADF;
_cleanup_close_pair_ int pair[2] = EBADF_PAIR;
pid_t child;
int r;
assert(pid > 0);
r = namespace_open(pid, &pidnsfd, &mntnsfd, /* ret_netns_fd = */ 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_SIGKILL,
pidnsfd, mntnsfd, -1, usernsfd, rootfd, &child);
if (r < 0)
return r;
if (r == 0) {
pair[0] = safe_close(pair[0]);
fd = openpt_allocate(flags, NULL);
if (fd < 0)
_exit(EXIT_FAILURE);
if (send_one_fd(pair[1], fd, 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;
fd = receive_one_fd(pair[0], 0);
if (fd < 0)
return fd;
if (ret_slave) {
r = ptsname_namespace(fd, ret_slave);
if (r < 0)
return r;
}
return TAKE_FD(fd);
}
int open_terminal_in_namespace(pid_t pid, const char *name, int mode) {
_cleanup_close_ int pidnsfd = -EBADF, mntnsfd = -EBADF, usernsfd = -EBADF, rootfd = -EBADF;
_cleanup_close_pair_ int pair[2] = EBADF_PAIR;
pid_t child;
int r;
r = namespace_open(pid, &pidnsfd, &mntnsfd, /* ret_netns_fd = */ 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_SIGKILL,
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 on_dev_null(void) {
struct stat dst, ost, est;
if (cached_on_dev_null >= 0)
return cached_on_dev_null;
if (stat("/dev/null", &dst) < 0 || fstat(STDOUT_FILENO, &ost) < 0 || fstat(STDERR_FILENO, &est) < 0)
cached_on_dev_null = false;
else
cached_on_dev_null = stat_inode_same(&dst, &ost) && stat_inode_same(&dst, &est);
return cached_on_dev_null;
}
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() && !on_dev_null())
return true;
return getenv_terminal_is_dumb();
}
static ColorMode parse_systemd_colors(void) {
const char *e;
int r;
e = getenv("SYSTEMD_COLORS");
if (!e)
return _COLOR_INVALID;
if (streq(e, "16"))
return COLOR_16;
if (streq(e, "256"))
return COLOR_256;
r = parse_boolean(e);
if (r >= 0)
return r > 0 ? COLOR_ON : COLOR_OFF;
return _COLOR_INVALID;
}
ColorMode get_color_mode(void) {
/* Returns the mode used to choose output colors. The possible modes are COLOR_OFF for no colors,
* COLOR_16 for only the base 16 ANSI colors, COLOR_256 for more colors and COLOR_ON for unrestricted
* color output. For that we check $SYSTEMD_COLORS first (which is the explicit way to
* change the mode). 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 continuously due to fear
* of SAK, and hence things are a bit weird. */
ColorMode m;
if (cached_color_mode < 0) {
m = parse_systemd_colors();
if (m >= 0)
cached_color_mode = m;
else if (getenv("NO_COLOR"))
/* We only check for the presence of the variable; value is ignored. */
cached_color_mode = COLOR_OFF;
else if (getpid_cached() == 1) {
/* PID1 outputs to the console without holding it open all the time.
*
* Note that the Linux console can only display 16 colors. We still enable 256 color
* mode even for PID1 output though (which typically goes to the Linux console),
* since the Linux console is able to parse the 256 color sequences and automatically
* map them to the closest color in the 16 color palette (since kernel 3.16). Doing
* 256 colors is nice for people who invoke systemd in a container or via a serial
* link or such, and use a true 256 color terminal to do so. */
if (getenv_terminal_is_dumb())
cached_color_mode = COLOR_OFF;
} else {
if (terminal_is_dumb())
cached_color_mode = COLOR_OFF;
}
if (cached_color_mode < 0) {
/* We failed to figure out any reason to *disable* colors.
* Let's see how many colors we shall use. */
if (STRPTR_IN_SET(getenv("COLORTERM"),
"truecolor",
"24bit"))
cached_color_mode = COLOR_24BIT;
else
cached_color_mode = COLOR_256;
}
}
return cached_color_mode;
}
bool dev_console_colors_enabled(void) {
_cleanup_free_ char *s = NULL;
ColorMode m;
/* 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. */
m = parse_systemd_colors();
if (m >= 0)
return m;
if (getenv("NO_COLOR"))
return false;
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;
return RET_NERRNO(ioctl(fd, KDSKBMODE, kb));
}
int vt_restore(int fd) {
static const struct vt_mode mode = {
.mode = VT_AUTO,
};
int r, ret = 0;
assert(fd >= 0);
if (!isatty_safe(fd))
return log_debug_errno(errno, "Asked to restore the VT for an fd that does not refer to a terminal: %m");
if (ioctl(fd, KDSETMODE, KD_TEXT) < 0)
RET_GATHER(ret, log_debug_errno(errno, "Failed to set VT to text mode, ignoring: %m"));
r = vt_reset_keyboard(fd);
if (r < 0)
RET_GATHER(ret, log_debug_errno(r, "Failed to reset keyboard mode, ignoring: %m"));
if (ioctl(fd, VT_SETMODE, &mode) < 0)
RET_GATHER(ret, log_debug_errno(errno, "Failed to set VT_AUTO mode, ignoring: %m"));
r = fchmod_and_chown(fd, TTY_MODE, 0, GID_INVALID);
if (r < 0)
RET_GATHER(ret, log_debug_errno(r, "Failed to chmod()/chown() VT, ignoring: %m"));
return ret;
}
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 (!isatty_safe(fd))
return log_debug_errno(errno, "Asked to release the VT for an fd that does not refer to a terminal: %m");
if (ioctl(fd, VT_RELDISP, 1) < 0)
return -errno;
if (restore)
return vt_restore(fd);
return 0;
}
void get_log_colors(int priority, const char **on, const char **off, const char **highlight) {
/* Note that this will initialize output variables only when there's something to output.
* The caller must pre-initialize to "" or NULL as appropriate. */
if (priority <= LOG_ERR) {
if (on)
*on = ansi_highlight_red();
if (off)
*off = ansi_normal();
if (highlight)
*highlight = ansi_highlight();
} else if (priority <= LOG_WARNING) {
if (on)
*on = ansi_highlight_yellow();
if (off)
*off = ansi_normal();
if (highlight)
*highlight = ansi_highlight();
} else if (priority <= LOG_NOTICE) {
if (on)
*on = ansi_highlight();
if (off)
*off = ansi_normal();
if (highlight)
*highlight = ansi_highlight_red();
} else if (priority >= LOG_DEBUG) {
if (on)
*on = ansi_grey();
if (off)
*off = ansi_normal();
if (highlight)
*highlight = ansi_highlight_red();
}
}
int set_terminal_cursor_position(int fd, unsigned int row, unsigned int column) {
int r;
char cursor_position[STRLEN("\x1B[") + DECIMAL_STR_MAX(int) * 2 + STRLEN(";H") + 1];
assert(fd >= 0);
xsprintf(cursor_position, "\x1B[%u;%uH", row, column);
r = loop_write(fd, cursor_position, SIZE_MAX);
if (r < 0)
return log_warning_errno(r, "Failed to set cursor position, ignoring: %m");
return 0;
}
void termios_disable_echo(struct termios *termios) {
assert(termios);
termios->c_lflag &= ~(ICANON|ECHO);
termios->c_cc[VMIN] = 1;
termios->c_cc[VTIME] = 0;
}
typedef enum BackgroundColorState {
BACKGROUND_TEXT,
BACKGROUND_ESCAPE,
BACKGROUND_BRACKET,
BACKGROUND_FIRST_ONE,
BACKGROUND_SECOND_ONE,
BACKGROUND_SEMICOLON,
BACKGROUND_R,
BACKGROUND_G,
BACKGROUND_B,
BACKGROUND_RED,
BACKGROUND_GREEN,
BACKGROUND_BLUE,
BACKGROUND_STRING_TERMINATOR,
} BackgroundColorState;
typedef struct BackgroundColorContext {
BackgroundColorState state;
uint32_t red, green, blue;
unsigned red_bits, green_bits, blue_bits;
} BackgroundColorContext;
static int scan_background_color_response(
BackgroundColorContext *context,
const char *buf,
size_t size) {
assert(context);
assert(buf || size == 0);
for (size_t i = 0; i < size; i++) {
char c = buf[i];
switch (context->state) {
case BACKGROUND_TEXT:
context->state = c == '\x1B' ? BACKGROUND_ESCAPE : BACKGROUND_TEXT;
break;
case BACKGROUND_ESCAPE:
context->state = c == ']' ? BACKGROUND_BRACKET : BACKGROUND_TEXT;
break;
case BACKGROUND_BRACKET:
context->state = c == '1' ? BACKGROUND_FIRST_ONE : BACKGROUND_TEXT;
break;
case BACKGROUND_FIRST_ONE:
context->state = c == '1' ? BACKGROUND_SECOND_ONE : BACKGROUND_TEXT;
break;
case BACKGROUND_SECOND_ONE:
context->state = c == ';' ? BACKGROUND_SEMICOLON : BACKGROUND_TEXT;
break;
case BACKGROUND_SEMICOLON:
context->state = c == 'r' ? BACKGROUND_R : BACKGROUND_TEXT;
break;
case BACKGROUND_R:
context->state = c == 'g' ? BACKGROUND_G : BACKGROUND_TEXT;
break;
case BACKGROUND_G:
context->state = c == 'b' ? BACKGROUND_B : BACKGROUND_TEXT;
break;
case BACKGROUND_B:
context->state = c == ':' ? BACKGROUND_RED : BACKGROUND_TEXT;
break;
case BACKGROUND_RED:
if (c == '/')
context->state = context->red_bits > 0 ? BACKGROUND_GREEN : BACKGROUND_TEXT;
else {
int d = unhexchar(c);
if (d < 0 || context->red_bits >= sizeof(context->red)*8)
context->state = BACKGROUND_TEXT;
else {
context->red = (context->red << 4) | d;
context->red_bits += 4;
}
}
break;
case BACKGROUND_GREEN:
if (c == '/')
context->state = context->green_bits > 0 ? BACKGROUND_BLUE : BACKGROUND_TEXT;
else {
int d = unhexchar(c);
if (d < 0 || context->green_bits >= sizeof(context->green)*8)
context->state = BACKGROUND_TEXT;
else {
context->green = (context->green << 4) | d;
context->green_bits += 4;
}
}
break;
case BACKGROUND_BLUE:
if (c == '\x07') {
if (context->blue_bits > 0)
return 1; /* success! */
context->state = BACKGROUND_TEXT;
} else if (c == '\x1b')
context->state = context->blue_bits > 0 ? BACKGROUND_STRING_TERMINATOR : BACKGROUND_TEXT;
else {
int d = unhexchar(c);
if (d < 0 || context->blue_bits >= sizeof(context->blue)*8)
context->state = BACKGROUND_TEXT;
else {
context->blue = (context->blue << 4) | d;
context->blue_bits += 4;
}
}
break;
case BACKGROUND_STRING_TERMINATOR:
if (c == '\\')
return 1; /* success! */
context->state = c == ']' ? BACKGROUND_ESCAPE : BACKGROUND_TEXT;
break;
}
/* Reset any colors we might have picked up */
if (IN_SET(context->state, BACKGROUND_TEXT, BACKGROUND_ESCAPE)) {
/* reset color */
context->red = context->green = context->blue = 0;
context->red_bits = context->green_bits = context->blue_bits = 0;
}
}
return 0; /* all good, but not enough data yet */
}
int get_default_background_color(double *ret_red, double *ret_green, double *ret_blue) {
int r;
assert(ret_red);
assert(ret_green);
assert(ret_blue);
if (!colors_enabled())
return -EOPNOTSUPP;
if (!isatty(STDIN_FILENO) || !isatty(STDOUT_FILENO))
return -EOPNOTSUPP;
if (streq_ptr(getenv("TERM"), "linux")) {
/* Linux console is black */
*ret_red = *ret_green = *ret_blue = 0.0;
return 0;
}
struct termios old_termios;
if (tcgetattr(STDIN_FILENO, &old_termios) < 0)
return -errno;
struct termios new_termios = old_termios;
termios_disable_echo(&new_termios);
if (tcsetattr(STDOUT_FILENO, TCSADRAIN, &new_termios) < 0)
return -errno;
r = loop_write(STDOUT_FILENO, "\x1B]11;?\x07", SIZE_MAX);
if (r < 0)
goto finish;
usec_t end = usec_add(now(CLOCK_MONOTONIC), 100 * USEC_PER_MSEC);
char buf[256];
size_t buf_full = 0;
BackgroundColorContext context = {};
for (;;) {
usec_t n = now(CLOCK_MONOTONIC);
if (n >= end) {
r = -EOPNOTSUPP;
goto finish;
}
r = fd_wait_for_event(STDIN_FILENO, POLLIN, usec_sub_unsigned(end, n));
if (r < 0)
goto finish;
if (r == 0) {
r = -EOPNOTSUPP;
goto finish;
}
ssize_t l;
l = read(STDIN_FILENO, buf, sizeof(buf) - buf_full);
if (l < 0) {
r = -errno;
goto finish;
}
buf_full += l;
assert(buf_full <= sizeof(buf));
r = scan_background_color_response(&context, buf, buf_full);
if (r < 0)
goto finish;
if (r > 0) {
assert(context.red_bits > 0);
*ret_red = (double) context.red / ((UINT64_C(1) << context.red_bits) - 1);
assert(context.green_bits > 0);
*ret_green = (double) context.green / ((UINT64_C(1) << context.green_bits) - 1);
assert(context.blue_bits > 0);
*ret_blue = (double) context.blue / ((UINT64_C(1) << context.blue_bits) - 1);
r = 0;
goto finish;
}
}
finish:
(void) tcsetattr(STDOUT_FILENO, TCSADRAIN, &old_termios);
return r;
}
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