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Systemd/src/basic/terminal-util.c

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/* SPDX-License-Identifier: LGPL-2.1+ */
/***
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 <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <stdarg.h>
#include <stddef.h>
#include <stdlib.h>
#include <string.h>
#include <sys/inotify.h>
#include <sys/socket.h>
#include <sys/sysmacros.h>
#include <sys/time.h>
#include <linux/kd.h>
#include <linux/tiocl.h>
#include <linux/vt.h>
#include <poll.h>
#include <signal.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <termios.h>
#include <unistd.h>
#include "alloc-util.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) {
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 > 0 ? -errno : -EIO;
truncate_nl(line);
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, ...) {
assert(ret);
assert(text);
for (;;) {
char line[LINE_MAX];
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);
errno = 0;
if (!fgets(line, sizeof(line), stdin))
return errno > 0 ? -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 */
(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);
}
r = fd;
fd = -1;
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;
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 = 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 = 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) {
if (cached_on_tty < 0)
cached_on_tty = isatty(STDOUT_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 *_devnr, char **r) {
char fn[STRLEN("/dev/char/") + 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;
}
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 = safe_fork("(sd-openpt)", FORK_RESET_SIGNALS|FORK_DEATHSIG, &child);
if (r < 0)
return r;
if (r == 0) {
int master;
pair[0] = safe_close(pair[0]);
r = namespace_enter(pidnsfd, mntnsfd, -1, usernsfd, rootfd);
if (r < 0)
_exit(EXIT_FAILURE);
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-openpt)", 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 = safe_fork("(sd-terminal)", FORK_RESET_SIGNALS|FORK_DEATHSIG, &child);
if (r < 0)
return r;
if (r == 0) {
int master;
pair[0] = safe_close(pair[0]);
r = namespace_enter(pidnsfd, mntnsfd, -1, usernsfd, rootfd);
if (r < 0)
_exit(EXIT_FAILURE);
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-terminal)", 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;
}
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