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systemd/src/basic/terminal-util.c
T
Lennart Poettering 7176f06c9e basic: split out dev_t related calls into new devno-util.[ch] 
No actual code changes, just splitting out of some dev_t handling
related calls from stat-util.[ch], they are quite a number already, and
deserve their own module now I think.

Also, try to settle on the name "devnum" as the name for the concept,
instead of "devno" or "dev" or "devid". "devnum" is the name exported in
udev APIs, hence probably best to stick to that. (this just renames a
few symbols to "devum", local variables are left untouched, to make the
patch not too invasive)

No actual code changes.
2022-04-13 16:26:31 +02:00

1450 lines
43 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 "def.h"
#include "devnum-util.h"
#include "env-util.h"
#include "fd-util.h"
#include "fileio.h"
#include "fs-util.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"
#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_color_mode = _COLOR_INVALID;
static volatile int cached_underline_enabled = -1;
int chvt(int vt) {
_cleanup_close_ int fd = -1;
/* 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 = 0;
/* Set terminal to some sane defaults */
assert(fd >= 0);
if (isatty(fd) < 1)
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 */
(void) vt_reset_keyboard(fd);
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;
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) {
_cleanup_close_ int fd = -1;
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(50 * USEC_PER_MSEC);
c++;
}
if (isatty(fd) < 1)
return negative_errno();
return TAKE_FD(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 = 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 = -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 = 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 = -1;
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 = -1;
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, false);
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 {
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, *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;
}
/* 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;
}
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], *c; /* 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;
c = strdup(skip_dev_prefix(path));
if (!c)
return -ENOMEM;
*ret = c;
return 0;
}
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 (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) {
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) {
_cleanup_free_ char *b = NULL;
b = strdup(w);
if (!b)
return -ENOMEM;
*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);
if (l > SIZE_MAX / 2)
return -ENOMEM;
l *= 2;
}
}
int openpt_allocate(int flags, char **ret_slave) {
_cleanup_close_ int fd = -1;
_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 = -1, mntnsfd = -1, usernsfd = -1, rootfd = -1, fd = -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) {
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 = -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();
}
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. */
cached_color_mode = getenv_terminal_is_dumb() ? COLOR_OFF : COLOR_256;
else
cached_color_mode = terminal_is_dumb() ? COLOR_OFF : 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, q = 0;
if (isatty(fd) < 1)
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)
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;
}
if (ioctl(fd, VT_SETMODE, &mode) < 0) {
log_debug_errno(errno, "Failed to set VT_AUTO mode, ignoring: %m");
if (q >= 0)
q = -errno;
}
r = fchmod_and_chown(fd, TTY_MODE, 0, GID_INVALID);
if (r < 0) {
log_debug_errno(r, "Failed to chmod()/chown() VT, ignoring: %m");
if (q >= 0)
q = r;
}
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 (isatty(fd) < 1)
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();
}
}
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