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Systemd/src/basic/terminal-util.c
Lennart Poettering 0c69794138 tree-wide: remove Lennart's copyright lines 
These lines are generally out-of-date, incomplete and unnecessary. With
SPDX and git repository much more accurate and fine grained information
about licensing and authorship is available, hence let's drop the
per-file copyright notice. Of course, removing copyright lines of others
is problematic, hence this commit only removes my own lines and leaves
all others untouched. It might be nicer if sooner or later those could
go away too, making git the only and accurate source of authorship
information.
2018-06-14 10:20:20 +02:00

1452 lines
41 KiB
C
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/* SPDX-License-Identifier: LGPL-2.1+ */
#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 <string.h>
#include <sys/inotify.h>
#include <sys/ioctl.h>
#include <sys/socket.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 "copy.h"
#include "def.h"
#include "env-util.h"
#include "fd-util.h"
#include "fileio.h"
#include "fs-util.h"
#include "io-util.h"
#include "log.h"
#include "macro.h"
#include "pager.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);
}
return TAKE_FD(fd);
}
int release_terminal(void) {
static const struct sigaction sa_new = {
.sa_handler = SIG_IGN,
.sa_flags = SA_RESTART,
};
_cleanup_close_ int fd = -1;
struct sigaction sa_old;
int r;
fd = open("/dev/tty", O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
if (fd < 0)
return -errno;
/* Temporarily ignore SIGHUP, so that we don't get SIGHUP'ed
* by our own TIOCNOTTY */
assert_se(sigaction(SIGHUP, &sa_new, &sa_old) == 0);
r = ioctl(fd, TIOCNOTTY) < 0 ? -errno : 0;
assert_se(sigaction(SIGHUP, &sa_old, NULL) == 0);
return r;
}
int terminal_vhangup_fd(int fd) {
assert(fd >= 0);
if (ioctl(fd, TIOCVHANGUP) < 0)
return -errno;
return 0;
}
int terminal_vhangup(const char *name) {
_cleanup_close_ int fd;
fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
if (fd < 0)
return fd;
return terminal_vhangup_fd(fd);
}
int vt_disallocate(const char *name) {
_cleanup_close_ int fd = -1;
const char *e, *n;
unsigned u;
int r;
/* Deallocate the VT if possible. If not possible
* (i.e. because it is the active one), at least clear it
* entirely (including the scrollback buffer) */
e = path_startswith(name, "/dev/");
if (!e)
return -EINVAL;
if (!tty_is_vc(name)) {
/* So this is not a VT. I guess we cannot deallocate
* it then. But let's at least clear the screen */
fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC);
if (fd < 0)
return fd;
loop_write(fd,
"\033[r" /* clear scrolling region */
"\033[H" /* move home */
"\033[2J", /* clear screen */
10, false);
return 0;
}
n = startswith(e, "tty");
if (!n)
return -EINVAL;
r = safe_atou(n, &u);
if (r < 0)
return r;
if (u <= 0)
return -EINVAL;
/* Try to deallocate */
fd = open_terminal("/dev/tty0", O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
if (fd < 0)
return fd;
r = ioctl(fd, VT_DISALLOCATE, u);
fd = safe_close(fd);
if (r >= 0)
return 0;
if (errno != EBUSY)
return -errno;
/* Couldn't deallocate, so let's clear it fully with
* scrollback */
fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC);
if (fd < 0)
return fd;
loop_write(fd,
"\033[r" /* clear scrolling region */
"\033[H" /* move home */
"\033[3J", /* clear screen including scrollback, requires Linux 2.6.40 */
10, false);
return 0;
}
int make_console_stdio(void) {
int fd, r;
/* Make /dev/console the controlling terminal and stdin/stdout/stderr */
fd = acquire_terminal("/dev/console", ACQUIRE_TERMINAL_FORCE|ACQUIRE_TERMINAL_PERMISSIVE, USEC_INFINITY);
if (fd < 0)
return log_error_errno(fd, "Failed to acquire terminal: %m");
r = reset_terminal_fd(fd, true);
if (r < 0)
log_warning_errno(r, "Failed to reset terminal, ignoring: %m");
r = rearrange_stdio(fd, fd, fd); /* This invalidates 'fd' both on success and on failure. */
if (r < 0)
return log_error_errno(r, "Failed to make terminal stdin/stdout/stderr: %m");
reset_terminal_feature_caches();
return 0;
}
bool tty_is_vc(const char *tty) {
assert(tty);
return vtnr_from_tty(tty) >= 0;
}
bool tty_is_console(const char *tty) {
assert(tty);
return streq(skip_dev_prefix(tty), "console");
}
int vtnr_from_tty(const char *tty) {
int i, r;
assert(tty);
tty = skip_dev_prefix(tty);
if (!startswith(tty, "tty") )
return -EINVAL;
if (tty[3] < '0' || tty[3] > '9')
return -EINVAL;
r = safe_atoi(tty+3, &i);
if (r < 0)
return r;
if (i < 0 || i > 63)
return -EINVAL;
return i;
}
int resolve_dev_console(char **ret) {
_cleanup_free_ char *active = NULL;
char *tty;
int r;
assert(ret);
/* Resolve where /dev/console is pointing to, if /sys is actually ours (i.e. not read-only-mounted which is a
* sign for container setups) */
if (path_is_read_only_fs("/sys") > 0)
return -ENOMEDIUM;
r = read_one_line_file("/sys/class/tty/console/active", &active);
if (r < 0)
return r;
/* If multiple log outputs are configured the last one is what /dev/console points to */
tty = strrchr(active, ' ');
if (tty)
tty++;
else
tty = active;
if (streq(tty, "tty0")) {
active = mfree(active);
/* Get the active VC (e.g. tty1) */
r = read_one_line_file("/sys/class/tty/tty0/active", &active);
if (r < 0)
return r;
tty = active;
}
if (tty == active)
*ret = TAKE_PTR(active);
else {
char *tmp;
tmp = strdup(tty);
if (!tmp)
return -ENOMEM;
*ret = tmp;
}
return 0;
}
int get_kernel_consoles(char ***ret) {
_cleanup_strv_free_ char **l = NULL;
_cleanup_free_ char *line = NULL;
const char *p;
int r;
assert(ret);
/* If /sys is mounted read-only this means we are running in some kind of container environment. In that
* case /sys would reflect the host system, not us, hence ignore the data we can read from it. */
if (path_is_read_only_fs("/sys") > 0)
goto fallback;
r = read_one_line_file("/sys/class/tty/console/active", &line);
if (r < 0)
return r;
p = line;
for (;;) {
_cleanup_free_ char *tty = NULL;
char *path;
r = extract_first_word(&p, &tty, NULL, 0);
if (r < 0)
return r;
if (r == 0)
break;
if (streq(tty, "tty0")) {
tty = mfree(tty);
r = read_one_line_file("/sys/class/tty/tty0/active", &tty);
if (r < 0)
return r;
}
path = strappend("/dev/", tty);
if (!path)
return -ENOMEM;
if (access(path, F_OK) < 0) {
log_debug_errno(errno, "Console device %s is not accessible, skipping: %m", path);
free(path);
continue;
}
r = strv_consume(&l, path);
if (r < 0)
return r;
}
if (strv_isempty(l)) {
log_debug("No devices found for system console");
goto fallback;
}
*ret = TAKE_PTR(l);
return 0;
fallback:
r = strv_extend(&l, "/dev/console");
if (r < 0)
return r;
*ret = TAKE_PTR(l);
return 0;
}
bool tty_is_vc_resolve(const char *tty) {
_cleanup_free_ char *resolved = NULL;
assert(tty);
tty = skip_dev_prefix(tty);
if (streq(tty, "console")) {
if (resolve_dev_console(&resolved) < 0)
return false;
tty = resolved;
}
return tty_is_vc(tty);
}
const char *default_term_for_tty(const char *tty) {
return tty && tty_is_vc_resolve(tty) ? "linux" : "vt220";
}
int fd_columns(int fd) {
struct winsize ws = {};
if (ioctl(fd, TIOCGWINSZ, &ws) < 0)
return -errno;
if (ws.ws_col <= 0)
return -EIO;
return ws.ws_col;
}
unsigned columns(void) {
const char *e;
int c;
if (cached_columns > 0)
return cached_columns;
c = 0;
e = getenv("COLUMNS");
if (e)
(void) safe_atoi(e, &c);
if (c <= 0)
c = 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) {
/* We check both stdout and stderr, so that situations where pipes on the shell are used are reliably
* recognized, regardless if only the output or the errors are piped to some place. Since on_tty() is generally
* used to default to a safer, non-interactive, non-color mode of operation it's probably good to be defensive
* here, and check for both. Note that we don't check for STDIN_FILENO, because it should fine to use fancy
* terminal functionality when outputting stuff, even if the input is piped to us. */
if (cached_on_tty < 0)
cached_on_tty =
isatty(STDOUT_FILENO) > 0 &&
isatty(STDERR_FILENO) > 0;
return cached_on_tty;
}
int getttyname_malloc(int fd, char **ret) {
size_t l = 100;
int r;
assert(fd >= 0);
assert(ret);
for (;;) {
char path[l];
r = ttyname_r(fd, path, sizeof(path));
if (r == 0) {
char *c;
c = strdup(skip_dev_prefix(path));
if (!c)
return -ENOMEM;
*ret = c;
return 0;
}
if (r != ERANGE)
return -r;
l *= 2;
}
return 0;
}
int getttyname_harder(int fd, char **r) {
int k;
char *s = NULL;
k = getttyname_malloc(fd, &s);
if (k < 0)
return k;
if (streq(s, "tty")) {
free(s);
return get_ctty(0, NULL, r);
}
*r = s;
return 0;
}
int get_ctty_devnr(pid_t pid, dev_t *d) {
int r;
_cleanup_free_ char *line = NULL;
const char *p;
unsigned long ttynr;
assert(pid >= 0);
p = procfs_file_alloca(pid, "stat");
r = read_one_line_file(p, &line);
if (r < 0)
return r;
p = strrchr(line, ')');
if (!p)
return -EIO;
p++;
if (sscanf(p, " "
"%*c " /* state */
"%*d " /* ppid */
"%*d " /* pgrp */
"%*d " /* session */
"%lu ", /* ttynr */
&ttynr) != 1)
return -EIO;
if (major(ttynr) == 0 && minor(ttynr) == 0)
return -ENXIO;
if (d)
*d = (dev_t) ttynr;
return 0;
}
int get_ctty(pid_t pid, dev_t *_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;
}
static bool urlify_enabled(void) {
static int cached_urlify_enabled = -1;
/* Unfortunately 'less' doesn't support links like this yet 😭, hence let's disable this as long as there's a
* pager in effect. Let's drop this check as soon as less got fixed a and enough time passed so that it's safe
* to assume that a link-enabled 'less' version has hit most installations. */
if (cached_urlify_enabled < 0) {
int val;
val = getenv_bool("SYSTEMD_URLIFY");
if (val >= 0)
cached_urlify_enabled = val;
else
cached_urlify_enabled = colors_enabled() && !pager_have();
}
return cached_urlify_enabled;
}
int terminal_urlify(const char *url, const char *text, char **ret) {
char *n;
assert(url);
/* Takes an URL and a pretty string and formats it as clickable link for the terminal. See
* https://gist.github.com/egmontkob/eb114294efbcd5adb1944c9f3cb5feda for details. */
if (isempty(text))
text = url;
if (urlify_enabled())
n = strjoin("\x1B]8;;", url, "\a", text, "\x1B]8;;\a");
else
n = strdup(text);
if (!n)
return -ENOMEM;
*ret = n;
return 0;
}
int terminal_urlify_path(const char *path, const char *text, char **ret) {
_cleanup_free_ char *absolute = NULL;
struct utsname u;
const char *url;
int r;
assert(path);
/* Much like terminal_urlify() above, but takes a file system path as input
* and turns it into a proper file:// URL first. */
if (isempty(path))
return -EINVAL;
if (isempty(text))
text = path;
if (!urlify_enabled()) {
char *n;
n = strdup(text);
if (!n)
return -ENOMEM;
*ret = n;
return 0;
}
if (uname(&u) < 0)
return -errno;
if (!path_is_absolute(path)) {
r = path_make_absolute_cwd(path, &absolute);
if (r < 0)
return r;
path = absolute;
}
/* As suggested by https://gist.github.com/egmontkob/eb114294efbcd5adb1944c9f3cb5feda, let's include the local
* hostname here. Note that we don't use gethostname_malloc() or gethostname_strict() since we are interested
* in the raw string the kernel has set, whatever it may be, under the assumption that terminals are not overly
* careful with validating the strings either. */
url = strjoina("file://", u.nodename, path);
return terminal_urlify(url, text, ret);
}
static int cat_file(const char *filename, bool newline) {
_cleanup_fclose_ FILE *f = NULL;
_cleanup_free_ char *urlified = NULL;
int r;
f = fopen(filename, "re");
if (!f)
return -errno;
r = terminal_urlify_path(filename, NULL, &urlified);
if (r < 0)
return r;
printf("%s%s# %s%s\n",
newline ? "\n" : "",
ansi_highlight_blue(),
urlified,
ansi_normal());
fflush(stdout);
for (;;) {
_cleanup_free_ char *line = NULL;
r = read_line(f, LONG_LINE_MAX, &line);
if (r < 0)
return log_error_errno(r, "Failed to read \"%s\": %m", filename);
if (r == 0)
break;
puts(line);
}
return 0;
}
int cat_files(const char *file, char **dropins, CatFlags flags) {
char **path;
int r;
if (file) {
r = cat_file(file, false);
if (r == -ENOENT && (flags & CAT_FLAGS_MAIN_FILE_OPTIONAL))
printf("%s# config file %s not found%s\n",
ansi_highlight_magenta(),
file,
ansi_normal());
else if (r < 0)
return log_warning_errno(r, "Failed to cat %s: %m", file);
}
STRV_FOREACH(path, dropins) {
r = cat_file(*path, file || path != dropins);
if (r < 0)
return log_warning_errno(r, "Failed to cat %s: %m", *path);
}
return 0;
}
void print_separator(void) {
/* Outputs a separator line that resolves to whitespace when copied from the terminal. We do that by outputting
* one line filled with spaces with ANSI underline set, followed by a second (empty) line. */
if (underline_enabled()) {
size_t i, c;
c = columns();
flockfile(stdout);
fputs_unlocked(ANSI_UNDERLINE, stdout);
for (i = 0; i < c; i++)
fputc_unlocked(' ', stdout);
fputs_unlocked(ANSI_NORMAL "\n\n", stdout);
funlockfile(stdout);
} else
fputs("\n\n", stdout);
}
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