| /*-*- 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" |
| |
| struct PTYForward { |
| sd_event *event; |
| |
| int master; |
| |
| sd_event_source *stdin_event_source; |
| sd_event_source *stdout_event_source; |
| sd_event_source *master_event_source; |
| |
| sd_event_source *sigwinch_event_source; |
| |
| struct termios saved_stdin_attr; |
| struct termios saved_stdout_attr; |
| |
| bool saved_stdin:1; |
| bool saved_stdout:1; |
| |
| bool stdin_readable:1; |
| bool stdin_hangup:1; |
| bool stdout_writable:1; |
| bool stdout_hangup:1; |
| bool master_readable:1; |
| bool master_writable:1; |
| bool master_hangup:1; |
| |
| char in_buffer[LINE_MAX], out_buffer[LINE_MAX]; |
| size_t in_buffer_full, out_buffer_full; |
| |
| usec_t escape_timestamp; |
| unsigned escape_counter; |
| }; |
| |
| #define ESCAPE_USEC (1*USEC_PER_SEC) |
| |
| static bool look_for_escape(PTYForward *f, const char *buffer, size_t n) { |
| const char *p; |
| |
| assert(f); |
| assert(buffer); |
| assert(n > 0); |
| |
| for (p = buffer; p < buffer + n; p++) { |
| |
| /* Check for ^] */ |
| if (*p == 0x1D) { |
| usec_t nw = now(CLOCK_MONOTONIC); |
| |
| if (f->escape_counter == 0 || nw > f->escape_timestamp + ESCAPE_USEC) { |
| f->escape_timestamp = nw; |
| f->escape_counter = 1; |
| } else { |
| (f->escape_counter)++; |
| |
| if (f->escape_counter >= 3) |
| return true; |
| } |
| } else { |
| f->escape_timestamp = 0; |
| f->escape_counter = 0; |
| } |
| } |
| |
| return false; |
| } |
| |
| static int shovel(PTYForward *f) { |
| ssize_t k; |
| |
| assert(f); |
| |
| while ((f->stdin_readable && f->in_buffer_full <= 0) || |
| (f->master_writable && f->in_buffer_full > 0) || |
| (f->master_readable && f->out_buffer_full <= 0) || |
| (f->stdout_writable && f->out_buffer_full > 0)) { |
| |
| if (f->stdin_readable && f->in_buffer_full < LINE_MAX) { |
| |
| k = read(STDIN_FILENO, f->in_buffer + f->in_buffer_full, LINE_MAX - f->in_buffer_full); |
| if (k < 0) { |
| |
| if (errno == EAGAIN) |
| f->stdin_readable = false; |
| else if (errno == EIO || errno == EPIPE || errno == ECONNRESET) { |
| f->stdin_readable = false; |
| f->stdin_hangup = true; |
| |
| f->stdin_event_source = sd_event_source_unref(f->stdin_event_source); |
| } else { |
| log_error_errno(errno, "read(): %m"); |
| return sd_event_exit(f->event, EXIT_FAILURE); |
| } |
| } else if (k == 0) { |
| /* EOF on stdin */ |
| f->stdin_readable = false; |
| f->stdin_hangup = true; |
| |
| f->stdin_event_source = sd_event_source_unref(f->stdin_event_source); |
| } else { |
| /* Check if ^] has been |
| * pressed three times within |
| * one second. If we get this |
| * we quite immediately. */ |
| if (look_for_escape(f, f->in_buffer + f->in_buffer_full, k)) |
| return sd_event_exit(f->event, EXIT_FAILURE); |
| |
| f->in_buffer_full += (size_t) k; |
| } |
| } |
| |
| if (f->master_writable && f->in_buffer_full > 0) { |
| |
| k = write(f->master, f->in_buffer, f->in_buffer_full); |
| if (k < 0) { |
| |
| if (errno == EAGAIN || errno == EIO) |
| f->master_writable = false; |
| else if (errno == EPIPE || errno == ECONNRESET) { |
| f->master_writable = f->master_readable = false; |
| f->master_hangup = true; |
| |
| f->master_event_source = sd_event_source_unref(f->master_event_source); |
| } else { |
| log_error_errno(errno, "write(): %m"); |
| return sd_event_exit(f->event, EXIT_FAILURE); |
| } |
| } else { |
| assert(f->in_buffer_full >= (size_t) k); |
| memmove(f->in_buffer, f->in_buffer + k, f->in_buffer_full - k); |
| f->in_buffer_full -= k; |
| } |
| } |
| |
| if (f->master_readable && f->out_buffer_full < LINE_MAX) { |
| |
| k = read(f->master, f->out_buffer + f->out_buffer_full, LINE_MAX - f->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) |
| f->master_readable = false; |
| else if (errno == EPIPE || errno == ECONNRESET) { |
| f->master_readable = f->master_writable = false; |
| f->master_hangup = true; |
| |
| f->master_event_source = sd_event_source_unref(f->master_event_source); |
| } else { |
| log_error_errno(errno, "read(): %m"); |
| return sd_event_exit(f->event, EXIT_FAILURE); |
| } |
| } else |
| f->out_buffer_full += (size_t) k; |
| } |
| |
| if (f->stdout_writable && f->out_buffer_full > 0) { |
| |
| k = write(STDOUT_FILENO, f->out_buffer, f->out_buffer_full); |
| if (k < 0) { |
| |
| if (errno == EAGAIN) |
| f->stdout_writable = false; |
| else if (errno == EIO || errno == EPIPE || errno == ECONNRESET) { |
| f->stdout_writable = false; |
| f->stdout_hangup = true; |
| f->stdout_event_source = sd_event_source_unref(f->stdout_event_source); |
| } else { |
| log_error_errno(errno, "write(): %m"); |
| return sd_event_exit(f->event, EXIT_FAILURE); |
| } |
| |
| } else { |
| assert(f->out_buffer_full >= (size_t) k); |
| memmove(f->out_buffer, f->out_buffer + k, f->out_buffer_full - k); |
| f->out_buffer_full -= k; |
| } |
| } |
| } |
| |
| if (f->stdin_hangup || f->stdout_hangup || f->master_hangup) { |
| /* Exit the loop if any side hung up and if there's |
| * nothing more to write or nothing we could write. */ |
| |
| if ((f->out_buffer_full <= 0 || f->stdout_hangup) && |
| (f->in_buffer_full <= 0 || f->master_hangup)) |
| return sd_event_exit(f->event, EXIT_SUCCESS); |
| } |
| |
| return 0; |
| } |
| |
| static int on_master_event(sd_event_source *e, int fd, uint32_t revents, void *userdata) { |
| PTYForward *f = userdata; |
| |
| assert(f); |
| assert(e); |
| assert(e == f->master_event_source); |
| assert(fd >= 0); |
| assert(fd == f->master); |
| |
| if (revents & (EPOLLIN|EPOLLHUP)) |
| f->master_readable = true; |
| |
| if (revents & (EPOLLOUT|EPOLLHUP)) |
| f->master_writable = true; |
| |
| return shovel(f); |
| } |
| |
| static int on_stdin_event(sd_event_source *e, int fd, uint32_t revents, void *userdata) { |
| PTYForward *f = userdata; |
| |
| assert(f); |
| assert(e); |
| assert(e == f->stdin_event_source); |
| assert(fd >= 0); |
| assert(fd == STDIN_FILENO); |
| |
| if (revents & (EPOLLIN|EPOLLHUP)) |
| f->stdin_readable = true; |
| |
| return shovel(f); |
| } |
| |
| static int on_stdout_event(sd_event_source *e, int fd, uint32_t revents, void *userdata) { |
| PTYForward *f = userdata; |
| |
| assert(f); |
| assert(e); |
| assert(e == f->stdout_event_source); |
| assert(fd >= 0); |
| assert(fd == STDOUT_FILENO); |
| |
| if (revents & (EPOLLOUT|EPOLLHUP)) |
| f->stdout_writable = true; |
| |
| return shovel(f); |
| } |
| |
| static int on_sigwinch_event(sd_event_source *e, const struct signalfd_siginfo *si, void *userdata) { |
| PTYForward *f = userdata; |
| struct winsize ws; |
| |
| assert(f); |
| assert(e); |
| assert(e == f->sigwinch_event_source); |
| |
| /* The window size changed, let's forward that. */ |
| if (ioctl(STDOUT_FILENO, TIOCGWINSZ, &ws) >= 0) |
| (void)ioctl(f->master, TIOCSWINSZ, &ws); |
| |
| return 0; |
| } |
| |
| int pty_forward_new(sd_event *event, int master, PTYForward **ret) { |
| _cleanup_(pty_forward_freep) PTYForward *f = NULL; |
| struct winsize ws; |
| int r; |
| |
| f = new0(PTYForward, 1); |
| if (!f) |
| return -ENOMEM; |
| |
| if (event) |
| f->event = sd_event_ref(event); |
| else { |
| r = sd_event_default(&f->event); |
| if (r < 0) |
| return r; |
| } |
| |
| r = fd_nonblock(STDIN_FILENO, true); |
| if (r < 0) |
| return r; |
| |
| r = fd_nonblock(STDOUT_FILENO, true); |
| if (r < 0) |
| return r; |
| |
| r = fd_nonblock(master, true); |
| if (r < 0) |
| return r; |
| |
| f->master = master; |
| |
| if (ioctl(STDOUT_FILENO, TIOCGWINSZ, &ws) >= 0) |
| (void)ioctl(master, TIOCSWINSZ, &ws); |
| |
| if (tcgetattr(STDIN_FILENO, &f->saved_stdin_attr) >= 0) { |
| struct termios raw_stdin_attr; |
| |
| f->saved_stdin = true; |
| |
| raw_stdin_attr = f->saved_stdin_attr; |
| cfmakeraw(&raw_stdin_attr); |
| raw_stdin_attr.c_oflag = f->saved_stdin_attr.c_oflag; |
| tcsetattr(STDIN_FILENO, TCSANOW, &raw_stdin_attr); |
| } |
| |
| if (tcgetattr(STDOUT_FILENO, &f->saved_stdout_attr) >= 0) { |
| struct termios raw_stdout_attr; |
| |
| f->saved_stdout = true; |
| |
| raw_stdout_attr = f->saved_stdout_attr; |
| cfmakeraw(&raw_stdout_attr); |
| raw_stdout_attr.c_iflag = f->saved_stdout_attr.c_iflag; |
| raw_stdout_attr.c_lflag = f->saved_stdout_attr.c_lflag; |
| tcsetattr(STDOUT_FILENO, TCSANOW, &raw_stdout_attr); |
| } |
| |
| r = sd_event_add_io(f->event, &f->master_event_source, master, EPOLLIN|EPOLLOUT|EPOLLET, on_master_event, f); |
| if (r < 0) |
| return r; |
| |
| r = sd_event_add_io(f->event, &f->stdin_event_source, STDIN_FILENO, EPOLLIN|EPOLLET, on_stdin_event, f); |
| if (r < 0 && r != -EPERM) |
| return r; |
| |
| r = sd_event_add_io(f->event, &f->stdout_event_source, STDOUT_FILENO, EPOLLOUT|EPOLLET, on_stdout_event, f); |
| if (r == -EPERM) |
| /* stdout without epoll support. Likely redirected to regular file. */ |
| f->stdout_writable = true; |
| else if (r < 0) |
| return r; |
| |
| r = sd_event_add_signal(f->event, &f->sigwinch_event_source, SIGWINCH, on_sigwinch_event, f); |
| |
| *ret = f; |
| f = NULL; |
| |
| return 0; |
| } |
| |
| PTYForward *pty_forward_free(PTYForward *f) { |
| |
| if (f) { |
| sd_event_source_unref(f->stdin_event_source); |
| sd_event_source_unref(f->stdout_event_source); |
| sd_event_source_unref(f->master_event_source); |
| sd_event_unref(f->event); |
| |
| if (f->saved_stdout) |
| tcsetattr(STDOUT_FILENO, TCSANOW, &f->saved_stdout_attr); |
| if (f->saved_stdin) |
| tcsetattr(STDIN_FILENO, TCSANOW, &f->saved_stdin_attr); |
| |
| free(f); |
| } |
| |
| /* STDIN/STDOUT should not be nonblocking normally, so let's |
| * unconditionally reset it */ |
| fd_nonblock(STDIN_FILENO, false); |
| fd_nonblock(STDOUT_FILENO, false); |
| |
| return NULL; |
| } |