| /*-*- 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; |
| |
| } |