mirror of
https://github.com/systemd/systemd.git
synced 2024-11-14 15:21:37 +03:00
d60473c7ba
Apparently bash doesn't turn off non-blocking mode on stdin/stdout when reading from it, so be nice to bash. Ideally bash would do this on its own for robustness reasons, though. https://bugs.freedesktop.org/show_bug.cgi?id=70622
387 lines
16 KiB
C
387 lines
16 KiB
C
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
|
|
|
|
/***
|
|
This file is part of systemd.
|
|
|
|
Copyright 2010-2013 Lennart Poettering
|
|
|
|
systemd is free software; you can redistribute it and/or modify it
|
|
under the terms of the GNU Lesser General Public License as published by
|
|
the Free Software Foundation; either version 2.1 of the License, or
|
|
(at your option) any later version.
|
|
|
|
systemd is distributed in the hope that it will be useful, but
|
|
WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
Lesser General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Lesser General Public License
|
|
along with systemd; If not, see <http://www.gnu.org/licenses/>.
|
|
***/
|
|
|
|
#include <sys/epoll.h>
|
|
#include <sys/signalfd.h>
|
|
#include <sys/ioctl.h>
|
|
#include <limits.h>
|
|
#include <termios.h>
|
|
|
|
#include "util.h"
|
|
#include "ptyfwd.h"
|
|
|
|
#define ESCAPE_USEC USEC_PER_SEC
|
|
|
|
static bool look_for_escape(usec_t *timestamp, unsigned *counter, const char *buffer, size_t n) {
|
|
const char *p;
|
|
|
|
assert(timestamp);
|
|
assert(counter);
|
|
assert(buffer);
|
|
assert(n > 0);
|
|
|
|
for (p = buffer; p < buffer + n; p++) {
|
|
|
|
/* Check for ^] */
|
|
if (*p == 0x1D) {
|
|
usec_t nw = now(CLOCK_MONOTONIC);
|
|
|
|
if (*counter == 0 || nw > *timestamp + USEC_PER_SEC) {
|
|
*timestamp = nw;
|
|
*counter = 1;
|
|
} else {
|
|
(*counter)++;
|
|
|
|
if (*counter >= 3)
|
|
return true;
|
|
}
|
|
} else {
|
|
*timestamp = 0;
|
|
*counter = 0;
|
|
}
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
static int process_pty_loop(int master, sigset_t *mask, pid_t kill_pid, int signo) {
|
|
char in_buffer[LINE_MAX], out_buffer[LINE_MAX];
|
|
size_t in_buffer_full = 0, out_buffer_full = 0;
|
|
struct epoll_event stdin_ev, stdout_ev, master_ev, signal_ev;
|
|
bool stdin_readable = false, stdout_writable = false, master_readable = false, master_writable = false;
|
|
bool stdin_hangup = false, stdout_hangup = false, master_hangup = false;
|
|
bool tried_orderly_shutdown = false, process_signalfd = false, quit = false;
|
|
usec_t escape_timestamp = 0;
|
|
unsigned escape_counter = 0;
|
|
_cleanup_close_ int ep = -1, signal_fd = -1;
|
|
|
|
assert(master >= 0);
|
|
assert(mask);
|
|
assert(kill_pid == 0 || kill_pid > 1);
|
|
assert(signo >= 0 && signo < _NSIG);
|
|
|
|
fd_nonblock(STDIN_FILENO, true);
|
|
fd_nonblock(STDOUT_FILENO, true);
|
|
fd_nonblock(master, true);
|
|
|
|
signal_fd = signalfd(-1, mask, SFD_NONBLOCK|SFD_CLOEXEC);
|
|
if (signal_fd < 0) {
|
|
log_error("signalfd(): %m");
|
|
return -errno;
|
|
}
|
|
|
|
ep = epoll_create1(EPOLL_CLOEXEC);
|
|
if (ep < 0) {
|
|
log_error("Failed to create epoll: %m");
|
|
return -errno;
|
|
}
|
|
|
|
/* We read from STDIN only if this is actually a TTY,
|
|
* otherwise we assume non-interactivity. */
|
|
if (isatty(STDIN_FILENO)) {
|
|
zero(stdin_ev);
|
|
stdin_ev.events = EPOLLIN|EPOLLET;
|
|
stdin_ev.data.fd = STDIN_FILENO;
|
|
|
|
if (epoll_ctl(ep, EPOLL_CTL_ADD, STDIN_FILENO, &stdin_ev) < 0) {
|
|
log_error("Failed to register STDIN in epoll: %m");
|
|
return -errno;
|
|
}
|
|
}
|
|
|
|
zero(stdout_ev);
|
|
stdout_ev.events = EPOLLOUT|EPOLLET;
|
|
stdout_ev.data.fd = STDOUT_FILENO;
|
|
|
|
zero(master_ev);
|
|
master_ev.events = EPOLLIN|EPOLLOUT|EPOLLET;
|
|
master_ev.data.fd = master;
|
|
|
|
zero(signal_ev);
|
|
signal_ev.events = EPOLLIN;
|
|
signal_ev.data.fd = signal_fd;
|
|
|
|
if (epoll_ctl(ep, EPOLL_CTL_ADD, STDOUT_FILENO, &stdout_ev) < 0) {
|
|
if (errno != EPERM) {
|
|
log_error("Failed to register stdout in epoll: %m");
|
|
return -errno;
|
|
}
|
|
|
|
/* stdout without epoll support. Likely redirected to regular file. */
|
|
stdout_writable = true;
|
|
}
|
|
|
|
if (epoll_ctl(ep, EPOLL_CTL_ADD, master, &master_ev) < 0 ||
|
|
epoll_ctl(ep, EPOLL_CTL_ADD, signal_fd, &signal_ev) < 0) {
|
|
log_error("Failed to register fds in epoll: %m");
|
|
return -errno;
|
|
}
|
|
|
|
for (;;) {
|
|
struct epoll_event ev[16];
|
|
ssize_t k;
|
|
int i, nfds;
|
|
|
|
nfds = epoll_wait(ep, ev, ELEMENTSOF(ev), quit ? 0 : -1);
|
|
if (nfds < 0) {
|
|
|
|
if (errno == EINTR || errno == EAGAIN)
|
|
continue;
|
|
|
|
log_error("epoll_wait(): %m");
|
|
return -errno;
|
|
}
|
|
|
|
if (nfds == 0)
|
|
return 0;
|
|
|
|
for (i = 0; i < nfds; i++) {
|
|
if (ev[i].data.fd == STDIN_FILENO) {
|
|
|
|
if (ev[i].events & (EPOLLIN|EPOLLHUP))
|
|
stdin_readable = true;
|
|
|
|
} else if (ev[i].data.fd == STDOUT_FILENO) {
|
|
|
|
if (ev[i].events & (EPOLLOUT|EPOLLHUP))
|
|
stdout_writable = true;
|
|
|
|
} else if (ev[i].data.fd == master) {
|
|
|
|
if (ev[i].events & (EPOLLIN|EPOLLHUP))
|
|
master_readable = true;
|
|
|
|
if (ev[i].events & (EPOLLOUT|EPOLLHUP))
|
|
master_writable = true;
|
|
|
|
} else if (ev[i].data.fd == signal_fd)
|
|
process_signalfd = true;
|
|
}
|
|
|
|
while ((stdin_readable && in_buffer_full <= 0) ||
|
|
(master_writable && in_buffer_full > 0) ||
|
|
(master_readable && out_buffer_full <= 0) ||
|
|
(stdout_writable && out_buffer_full > 0)) {
|
|
|
|
if (stdin_readable && in_buffer_full < LINE_MAX) {
|
|
|
|
k = read(STDIN_FILENO, in_buffer + in_buffer_full, LINE_MAX - in_buffer_full);
|
|
if (k < 0) {
|
|
|
|
if (errno == EAGAIN)
|
|
stdin_readable = false;
|
|
else if (errno == EIO || errno == EPIPE || errno == ECONNRESET) {
|
|
stdin_readable = false;
|
|
stdin_hangup = true;
|
|
epoll_ctl(ep, EPOLL_CTL_DEL, STDIN_FILENO, NULL);
|
|
} else {
|
|
log_error("read(): %m");
|
|
return -errno;
|
|
}
|
|
} else {
|
|
/* Check if ^] has been
|
|
* pressed three times within
|
|
* one second. If we get this
|
|
* we quite immediately. */
|
|
if (look_for_escape(&escape_timestamp, &escape_counter, in_buffer + in_buffer_full, k))
|
|
return !quit;
|
|
|
|
in_buffer_full += (size_t) k;
|
|
}
|
|
}
|
|
|
|
if (master_writable && in_buffer_full > 0) {
|
|
|
|
k = write(master, in_buffer, in_buffer_full);
|
|
if (k < 0) {
|
|
|
|
if (errno == EAGAIN || errno == EIO)
|
|
master_writable = false;
|
|
else if (errno == EPIPE || errno == ECONNRESET) {
|
|
master_writable = master_readable = false;
|
|
master_hangup = true;
|
|
epoll_ctl(ep, EPOLL_CTL_DEL, master, NULL);
|
|
} else {
|
|
log_error("write(): %m");
|
|
return -errno;
|
|
}
|
|
|
|
} else {
|
|
assert(in_buffer_full >= (size_t) k);
|
|
memmove(in_buffer, in_buffer + k, in_buffer_full - k);
|
|
in_buffer_full -= k;
|
|
}
|
|
}
|
|
|
|
if (master_readable && out_buffer_full < LINE_MAX) {
|
|
|
|
k = read(master, out_buffer + out_buffer_full, LINE_MAX - out_buffer_full);
|
|
if (k < 0) {
|
|
|
|
/* Note that EIO on the master
|
|
* device might be cause by
|
|
* vhangup() or temporary
|
|
* closing of everything on
|
|
* the other side, we treat it
|
|
* like EAGAIN here and try
|
|
* again. */
|
|
|
|
if (errno == EAGAIN || errno == EIO)
|
|
master_readable = false;
|
|
else if (errno == EPIPE || errno == ECONNRESET) {
|
|
master_readable = master_writable = false;
|
|
master_hangup = true;
|
|
epoll_ctl(ep, EPOLL_CTL_DEL, master, NULL);
|
|
} else {
|
|
log_error("read(): %m");
|
|
return -errno;
|
|
}
|
|
} else
|
|
out_buffer_full += (size_t) k;
|
|
}
|
|
|
|
if (stdout_writable && out_buffer_full > 0) {
|
|
|
|
k = write(STDOUT_FILENO, out_buffer, out_buffer_full);
|
|
if (k < 0) {
|
|
|
|
if (errno == EAGAIN)
|
|
stdout_writable = false;
|
|
else if (errno == EIO || errno == EPIPE || errno == ECONNRESET) {
|
|
stdout_writable = false;
|
|
stdout_hangup = true;
|
|
epoll_ctl(ep, EPOLL_CTL_DEL, STDOUT_FILENO, NULL);
|
|
} else {
|
|
log_error("write(): %m");
|
|
return -errno;
|
|
}
|
|
|
|
} else {
|
|
assert(out_buffer_full >= (size_t) k);
|
|
memmove(out_buffer, out_buffer + k, out_buffer_full - k);
|
|
out_buffer_full -= k;
|
|
}
|
|
}
|
|
|
|
}
|
|
|
|
if (process_signalfd) {
|
|
struct signalfd_siginfo sfsi;
|
|
ssize_t n;
|
|
|
|
n = read(signal_fd, &sfsi, sizeof(sfsi));
|
|
if (n != sizeof(sfsi)) {
|
|
|
|
if (n >= 0) {
|
|
log_error("Failed to read from signalfd: invalid block size");
|
|
return -EIO;
|
|
}
|
|
|
|
if (errno != EINTR && errno != EAGAIN) {
|
|
log_error("Failed to read from signalfd: %m");
|
|
return -errno;
|
|
}
|
|
} else {
|
|
|
|
if (sfsi.ssi_signo == SIGWINCH) {
|
|
struct winsize ws;
|
|
|
|
/* The window size changed, let's forward that. */
|
|
if (ioctl(STDOUT_FILENO, TIOCGWINSZ, &ws) >= 0)
|
|
ioctl(master, TIOCSWINSZ, &ws);
|
|
|
|
} else if (sfsi.ssi_signo == SIGTERM && kill_pid > 0 && signo > 0 && !tried_orderly_shutdown) {
|
|
|
|
if (kill(kill_pid, signo) < 0)
|
|
quit = true;
|
|
else {
|
|
log_info("Trying to halt container. Send SIGTERM again to trigger immediate termination.");
|
|
|
|
/* This only works for systemd... */
|
|
tried_orderly_shutdown = true;
|
|
}
|
|
|
|
} else
|
|
/* Signals that where
|
|
* delivered via signalfd that
|
|
* we didn't know are a reason
|
|
* for us to quit */
|
|
quit = true;
|
|
}
|
|
}
|
|
|
|
if (stdin_hangup || stdout_hangup || master_hangup) {
|
|
/* Exit the loop if any side hung up and if
|
|
* there's nothing more to write or nothing we
|
|
* could write. */
|
|
|
|
if ((out_buffer_full <= 0 || stdout_hangup) &&
|
|
(in_buffer_full <= 0 || master_hangup))
|
|
return !quit;
|
|
}
|
|
}
|
|
}
|
|
|
|
int process_pty(int master, sigset_t *mask, pid_t kill_pid, int signo) {
|
|
struct termios saved_stdin_attr, raw_stdin_attr;
|
|
struct termios saved_stdout_attr, raw_stdout_attr;
|
|
bool saved_stdin = false;
|
|
bool saved_stdout = false;
|
|
struct winsize ws;
|
|
int r;
|
|
|
|
if (ioctl(STDOUT_FILENO, TIOCGWINSZ, &ws) >= 0)
|
|
ioctl(master, TIOCSWINSZ, &ws);
|
|
|
|
if (tcgetattr(STDIN_FILENO, &saved_stdin_attr) >= 0) {
|
|
saved_stdin = true;
|
|
|
|
raw_stdin_attr = saved_stdin_attr;
|
|
cfmakeraw(&raw_stdin_attr);
|
|
raw_stdin_attr.c_oflag = saved_stdin_attr.c_oflag;
|
|
tcsetattr(STDIN_FILENO, TCSANOW, &raw_stdin_attr);
|
|
}
|
|
if (tcgetattr(STDOUT_FILENO, &saved_stdout_attr) >= 0) {
|
|
saved_stdout = true;
|
|
|
|
raw_stdout_attr = saved_stdout_attr;
|
|
cfmakeraw(&raw_stdout_attr);
|
|
raw_stdout_attr.c_iflag = saved_stdout_attr.c_iflag;
|
|
raw_stdout_attr.c_lflag = saved_stdout_attr.c_lflag;
|
|
tcsetattr(STDOUT_FILENO, TCSANOW, &raw_stdout_attr);
|
|
}
|
|
|
|
r = process_pty_loop(master, mask, kill_pid, signo);
|
|
|
|
if (saved_stdout)
|
|
tcsetattr(STDOUT_FILENO, TCSANOW, &saved_stdout_attr);
|
|
if (saved_stdin)
|
|
tcsetattr(STDIN_FILENO, TCSANOW, &saved_stdin_attr);
|
|
|
|
/* STDIN/STDOUT should not be nonblocking normally, so let's
|
|
* unconditionally reset it */
|
|
fd_nonblock(STDIN_FILENO, false);
|
|
fd_nonblock(STDOUT_FILENO, false);
|
|
|
|
return r;
|
|
|
|
}
|