| /* SPDX-License-Identifier: LGPL-2.1-or-later */ |
| |
| #include <errno.h> |
| #include <fcntl.h> |
| #include <limits.h> |
| #include <signal.h> |
| #include <stddef.h> |
| #include <stdint.h> |
| #include <stdlib.h> |
| #include <string.h> |
| #include <sys/epoll.h> |
| #include <sys/ioctl.h> |
| #include <sys/time.h> |
| #include <termios.h> |
| #include <unistd.h> |
| |
| #include "sd-event.h" |
| |
| #include "alloc-util.h" |
| #include "errno-util.h" |
| #include "fd-util.h" |
| #include "log.h" |
| #include "macro.h" |
| #include "ptyfwd.h" |
| #include "terminal-util.h" |
| #include "time-util.h" |
| |
| struct PTYForward { |
| sd_event *event; |
| |
| int input_fd; |
| int output_fd; |
| int master; |
| |
| PTYForwardFlags flags; |
| |
| 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 close_input_fd:1; |
| bool close_output_fd:1; |
| |
| 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; |
| |
| bool read_from_master:1; |
| |
| bool done:1; |
| bool drain:1; |
| |
| bool last_char_set:1; |
| char last_char; |
| |
| char in_buffer[LINE_MAX], out_buffer[LINE_MAX]; |
| size_t in_buffer_full, out_buffer_full; |
| |
| usec_t escape_timestamp; |
| unsigned escape_counter; |
| |
| PTYForwardHandler handler; |
| void *userdata; |
| }; |
| |
| #define ESCAPE_USEC (1*USEC_PER_SEC) |
| |
| static void pty_forward_disconnect(PTYForward *f) { |
| |
| if (!f) |
| return; |
| |
| f->stdin_event_source = sd_event_source_unref(f->stdin_event_source); |
| f->stdout_event_source = sd_event_source_unref(f->stdout_event_source); |
| |
| f->master_event_source = sd_event_source_unref(f->master_event_source); |
| f->sigwinch_event_source = sd_event_source_unref(f->sigwinch_event_source); |
| f->event = sd_event_unref(f->event); |
| |
| if (f->output_fd >= 0) { |
| if (f->saved_stdout) |
| (void) tcsetattr(f->output_fd, TCSANOW, &f->saved_stdout_attr); |
| |
| /* STDIN/STDOUT should not be non-blocking normally, so let's reset it */ |
| (void) fd_nonblock(f->output_fd, false); |
| if (f->close_output_fd) |
| f->output_fd = safe_close(f->output_fd); |
| } |
| |
| if (f->input_fd >= 0) { |
| if (f->saved_stdin) |
| (void) tcsetattr(f->input_fd, TCSANOW, &f->saved_stdin_attr); |
| |
| (void) fd_nonblock(f->input_fd, false); |
| if (f->close_input_fd) |
| f->input_fd = safe_close(f->input_fd); |
| } |
| |
| f->saved_stdout = f->saved_stdin = false; |
| } |
| |
| static int pty_forward_done(PTYForward *f, int rcode) { |
| _cleanup_(sd_event_unrefp) sd_event *e = NULL; |
| assert(f); |
| |
| if (f->done) |
| return 0; |
| |
| e = sd_event_ref(f->event); |
| |
| f->done = true; |
| pty_forward_disconnect(f); |
| |
| if (f->handler) |
| return f->handler(f, rcode, f->userdata); |
| else |
| return sd_event_exit(e, rcode < 0 ? EXIT_FAILURE : rcode); |
| } |
| |
| 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 bool ignore_vhangup(PTYForward *f) { |
| assert(f); |
| |
| if (f->flags & PTY_FORWARD_IGNORE_VHANGUP) |
| return true; |
| |
| if ((f->flags & PTY_FORWARD_IGNORE_INITIAL_VHANGUP) && !f->read_from_master) |
| return true; |
| |
| return false; |
| } |
| |
| static bool drained(PTYForward *f) { |
| int q = 0; |
| |
| assert(f); |
| |
| if (f->out_buffer_full > 0) |
| return false; |
| |
| if (f->master_readable) |
| return false; |
| |
| if (ioctl(f->master, TIOCINQ, &q) < 0) |
| log_debug_errno(errno, "TIOCINQ failed on master: %m"); |
| else if (q > 0) |
| return false; |
| |
| if (ioctl(f->master, TIOCOUTQ, &q) < 0) |
| log_debug_errno(errno, "TIOCOUTQ failed on master: %m"); |
| else if (q > 0) |
| return false; |
| |
| return true; |
| } |
| |
| 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(f->input_fd, 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_IS_DISCONNECT(errno)) { |
| 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 pty_forward_done(f, -errno); |
| } |
| } 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 pty_forward_done(f, -ECANCELED); |
| |
| 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 (IN_SET(errno, EAGAIN, EIO)) |
| f->master_writable = false; |
| else if (IN_SET(errno, EPIPE, 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 pty_forward_done(f, -errno); |
| } |
| } 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 caused by vhangup() or |
| * temporary closing of everything on |
| * the other side, we treat it like |
| * EAGAIN here and try again, unless |
| * ignore_vhangup is off. */ |
| |
| if (errno == EAGAIN || (errno == EIO && ignore_vhangup(f))) |
| f->master_readable = false; |
| else if (IN_SET(errno, EPIPE, ECONNRESET, EIO)) { |
| 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 pty_forward_done(f, -errno); |
| } |
| } else { |
| f->read_from_master = true; |
| f->out_buffer_full += (size_t) k; |
| } |
| } |
| |
| if (f->stdout_writable && f->out_buffer_full > 0) { |
| |
| k = write(f->output_fd, f->out_buffer, f->out_buffer_full); |
| if (k < 0) { |
| |
| if (errno == EAGAIN) |
| f->stdout_writable = false; |
| else if (errno == EIO || ERRNO_IS_DISCONNECT(errno)) { |
| 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 pty_forward_done(f, -errno); |
| } |
| |
| } else { |
| |
| if (k > 0) { |
| f->last_char = f->out_buffer[k-1]; |
| f->last_char_set = true; |
| } |
| |
| 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 pty_forward_done(f, 0); |
| } |
| |
| /* If we were asked to drain, and there's nothing more to handle from the master, then call the callback |
| * too. */ |
| if (f->drain && drained(f)) |
| return pty_forward_done(f, 0); |
| |
| return 0; |
| } |
| |
| static int on_master_event(sd_event_source *e, int fd, uint32_t revents, void *userdata) { |
| PTYForward *f = ASSERT_PTR(userdata); |
| |
| 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 = ASSERT_PTR(userdata); |
| |
| assert(e); |
| assert(e == f->stdin_event_source); |
| assert(fd >= 0); |
| assert(fd == f->input_fd); |
| |
| 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 = ASSERT_PTR(userdata); |
| |
| assert(e); |
| assert(e == f->stdout_event_source); |
| assert(fd >= 0); |
| assert(fd == f->output_fd); |
| |
| 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 = ASSERT_PTR(userdata); |
| struct winsize ws; |
| |
| assert(e); |
| assert(e == f->sigwinch_event_source); |
| |
| /* The window size changed, let's forward that. */ |
| if (ioctl(f->output_fd, TIOCGWINSZ, &ws) >= 0) |
| (void) ioctl(f->master, TIOCSWINSZ, &ws); |
| |
| return 0; |
| } |
| |
| int pty_forward_new( |
| sd_event *event, |
| int master, |
| PTYForwardFlags flags, |
| PTYForward **ret) { |
| |
| _cleanup_(pty_forward_freep) PTYForward *f = NULL; |
| struct winsize ws; |
| int r; |
| |
| f = new(PTYForward, 1); |
| if (!f) |
| return -ENOMEM; |
| |
| *f = (struct PTYForward) { |
| .flags = flags, |
| .master = -EBADF, |
| .input_fd = -EBADF, |
| .output_fd = -EBADF, |
| }; |
| |
| if (event) |
| f->event = sd_event_ref(event); |
| else { |
| r = sd_event_default(&f->event); |
| if (r < 0) |
| return r; |
| } |
| |
| if (FLAGS_SET(flags, PTY_FORWARD_READ_ONLY)) |
| f->output_fd = STDOUT_FILENO; |
| else { |
| /* If we shall be invoked in interactive mode, let's switch on non-blocking mode, so that we |
| * never end up staving one direction while we block on the other. However, let's be careful |
| * here and not turn on O_NONBLOCK for stdin/stdout directly, but of re-opened copies of |
| * them. This has two advantages: when we are killed abruptly the stdin/stdout fds won't be |
| * left in O_NONBLOCK state for the next process using them. In addition, if some process |
| * running in the background wants to continue writing to our stdout it can do so without |
| * being confused by O_NONBLOCK. */ |
| |
| f->input_fd = fd_reopen(STDIN_FILENO, O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NONBLOCK); |
| if (f->input_fd < 0) { |
| /* Handle failures gracefully, after all certain fd types cannot be reopened |
| * (sockets, …) */ |
| log_debug_errno(f->input_fd, "Failed to reopen stdin, using original fd: %m"); |
| |
| r = fd_nonblock(STDIN_FILENO, true); |
| if (r < 0) |
| return r; |
| |
| f->input_fd = STDIN_FILENO; |
| } else |
| f->close_input_fd = true; |
| |
| f->output_fd = fd_reopen(STDOUT_FILENO, O_WRONLY|O_CLOEXEC|O_NOCTTY|O_NONBLOCK); |
| if (f->output_fd < 0) { |
| log_debug_errno(f->output_fd, "Failed to reopen stdout, using original fd: %m"); |
| |
| r = fd_nonblock(STDOUT_FILENO, true); |
| if (r < 0) |
| return r; |
| |
| f->output_fd = STDOUT_FILENO; |
| } else |
| f->close_output_fd = true; |
| } |
| |
| r = fd_nonblock(master, true); |
| if (r < 0) |
| return r; |
| |
| f->master = master; |
| |
| if (ioctl(f->output_fd, TIOCGWINSZ, &ws) < 0) |
| /* If we can't get the resolution from the output fd, then use our internal, regular width/height, |
| * i.e. something derived from $COLUMNS and $LINES if set. */ |
| ws = (struct winsize) { |
| .ws_row = lines(), |
| .ws_col = columns(), |
| }; |
| |
| (void) ioctl(master, TIOCSWINSZ, &ws); |
| |
| if (!(flags & PTY_FORWARD_READ_ONLY)) { |
| assert(f->input_fd >= 0); |
| |
| if (tcgetattr(f->input_fd, &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(f->input_fd, TCSANOW, &raw_stdin_attr); |
| } |
| |
| if (tcgetattr(f->output_fd, &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(f->output_fd, TCSANOW, &raw_stdout_attr); |
| } |
| |
| r = sd_event_add_io(f->event, &f->stdin_event_source, f->input_fd, EPOLLIN|EPOLLET, on_stdin_event, f); |
| if (r < 0 && r != -EPERM) |
| return r; |
| |
| if (r >= 0) |
| (void) sd_event_source_set_description(f->stdin_event_source, "ptyfwd-stdin"); |
| } |
| |
| r = sd_event_add_io(f->event, &f->stdout_event_source, f->output_fd, 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; |
| else |
| (void) sd_event_source_set_description(f->stdout_event_source, "ptyfwd-stdout"); |
| |
| r = sd_event_add_io(f->event, &f->master_event_source, master, EPOLLIN|EPOLLOUT|EPOLLET, on_master_event, f); |
| if (r < 0) |
| return r; |
| |
| (void) sd_event_source_set_description(f->master_event_source, "ptyfwd-master"); |
| |
| r = sd_event_add_signal(f->event, &f->sigwinch_event_source, SIGWINCH, on_sigwinch_event, f); |
| if (r < 0) |
| return r; |
| |
| (void) sd_event_source_set_description(f->sigwinch_event_source, "ptyfwd-sigwinch"); |
| |
| *ret = TAKE_PTR(f); |
| |
| return 0; |
| } |
| |
| PTYForward *pty_forward_free(PTYForward *f) { |
| pty_forward_disconnect(f); |
| return mfree(f); |
| } |
| |
| int pty_forward_get_last_char(PTYForward *f, char *ch) { |
| assert(f); |
| assert(ch); |
| |
| if (!f->last_char_set) |
| return -ENXIO; |
| |
| *ch = f->last_char; |
| return 0; |
| } |
| |
| int pty_forward_set_ignore_vhangup(PTYForward *f, bool b) { |
| int r; |
| |
| assert(f); |
| |
| if (!!(f->flags & PTY_FORWARD_IGNORE_VHANGUP) == b) |
| return 0; |
| |
| SET_FLAG(f->flags, PTY_FORWARD_IGNORE_VHANGUP, b); |
| |
| if (!ignore_vhangup(f)) { |
| |
| /* We shall now react to vhangup()s? Let's check |
| * immediately if we might be in one */ |
| |
| f->master_readable = true; |
| r = shovel(f); |
| if (r < 0) |
| return r; |
| } |
| |
| return 0; |
| } |
| |
| bool pty_forward_get_ignore_vhangup(PTYForward *f) { |
| assert(f); |
| |
| return !!(f->flags & PTY_FORWARD_IGNORE_VHANGUP); |
| } |
| |
| bool pty_forward_is_done(PTYForward *f) { |
| assert(f); |
| |
| return f->done; |
| } |
| |
| void pty_forward_set_handler(PTYForward *f, PTYForwardHandler cb, void *userdata) { |
| assert(f); |
| |
| f->handler = cb; |
| f->userdata = userdata; |
| } |
| |
| bool pty_forward_drain(PTYForward *f) { |
| assert(f); |
| |
| /* Starts draining the forwarder. Specifically: |
| * |
| * - Returns true if there are no unprocessed bytes from the pty, false otherwise |
| * |
| * - Makes sure the handler function is called the next time the number of unprocessed bytes hits zero |
| */ |
| |
| f->drain = true; |
| return drained(f); |
| } |
| |
| int pty_forward_set_priority(PTYForward *f, int64_t priority) { |
| int r; |
| assert(f); |
| |
| if (f->stdin_event_source) { |
| r = sd_event_source_set_priority(f->stdin_event_source, priority); |
| if (r < 0) |
| return r; |
| } |
| |
| r = sd_event_source_set_priority(f->stdout_event_source, priority); |
| if (r < 0) |
| return r; |
| |
| r = sd_event_source_set_priority(f->master_event_source, priority); |
| if (r < 0) |
| return r; |
| |
| r = sd_event_source_set_priority(f->sigwinch_event_source, priority); |
| if (r < 0) |
| return r; |
| |
| return 0; |
| } |
| |
| int pty_forward_set_width_height(PTYForward *f, unsigned width, unsigned height) { |
| struct winsize ws; |
| |
| assert(f); |
| |
| if (width == UINT_MAX && height == UINT_MAX) |
| return 0; /* noop */ |
| |
| if (width != UINT_MAX && |
| (width == 0 || width > USHRT_MAX)) |
| return -ERANGE; |
| |
| if (height != UINT_MAX && |
| (height == 0 || height > USHRT_MAX)) |
| return -ERANGE; |
| |
| if (width == UINT_MAX || height == UINT_MAX) { |
| if (ioctl(f->master, TIOCGWINSZ, &ws) < 0) |
| return -errno; |
| |
| if (width != UINT_MAX) |
| ws.ws_col = width; |
| if (height != UINT_MAX) |
| ws.ws_row = height; |
| } else |
| ws = (struct winsize) { |
| .ws_row = height, |
| .ws_col = width, |
| }; |
| |
| if (ioctl(f->master, TIOCSWINSZ, &ws) < 0) |
| return -errno; |
| |
| /* Make sure we ignore SIGWINCH window size events from now on */ |
| f->sigwinch_event_source = sd_event_source_unref(f->sigwinch_event_source); |
| |
| return 0; |
| } |
