diff options
| -rw-r--r-- | src/shared/ptyfwd.c | 113 |
1 files changed, 81 insertions, 32 deletions
diff --git a/src/shared/ptyfwd.c b/src/shared/ptyfwd.c index bb372d4001..305fd8a0f1 100644 --- a/src/shared/ptyfwd.c +++ b/src/shared/ptyfwd.c @@ -1,6 +1,7 @@ /* SPDX-License-Identifier: LGPL-2.1+ */ #include <errno.h> +#include <fcntl.h> #include <limits.h> #include <signal.h> #include <stddef.h> @@ -27,6 +28,8 @@ struct PTYForward { sd_event *event; + int input_fd; + int output_fd; int master; PTYForwardFlags flags; @@ -40,6 +43,9 @@ struct PTYForward { 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; @@ -73,25 +79,36 @@ struct PTYForward { static void pty_forward_disconnect(PTYForward *f) { - if (f) { - f->stdin_event_source = sd_event_source_unref(f->stdin_event_source); - f->stdout_event_source = sd_event_source_unref(f->stdout_event_source); + 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); + 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) - tcsetattr(STDOUT_FILENO, TCSANOW, &f->saved_stdout_attr); + (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) - tcsetattr(STDIN_FILENO, TCSANOW, &f->saved_stdin_attr); + (void) tcsetattr(f->input_fd, TCSANOW, &f->saved_stdin_attr); - f->saved_stdout = f->saved_stdin = false; + (void) fd_nonblock(f->input_fd, false); + if (f->close_input_fd) + f->input_fd = safe_close(f->input_fd); } - /* STDIN/STDOUT should not be nonblocking normally, so let's unconditionally reset it */ - (void) fd_nonblock(STDIN_FILENO, false); - (void) fd_nonblock(STDOUT_FILENO, false); + f->saved_stdout = f->saved_stdin = false; } static int pty_forward_done(PTYForward *f, int rcode) { @@ -191,7 +208,7 @@ static int shovel(PTYForward *f) { 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); + k = read(f->input_fd, f->in_buffer + f->in_buffer_full, LINE_MAX - f->in_buffer_full); if (k < 0) { if (errno == EAGAIN) @@ -275,7 +292,7 @@ static int shovel(PTYForward *f) { if (f->stdout_writable && f->out_buffer_full > 0) { - k = write(STDOUT_FILENO, f->out_buffer, f->out_buffer_full); + k = write(f->output_fd, f->out_buffer, f->out_buffer_full); if (k < 0) { if (errno == EAGAIN) @@ -345,7 +362,7 @@ static int on_stdin_event(sd_event_source *e, int fd, uint32_t revents, void *us assert(e); assert(e == f->stdin_event_source); assert(fd >= 0); - assert(fd == STDIN_FILENO); + assert(fd == f->input_fd); if (revents & (EPOLLIN|EPOLLHUP)) f->stdin_readable = true; @@ -360,7 +377,7 @@ static int on_stdout_event(sd_event_source *e, int fd, uint32_t revents, void *u assert(e); assert(e == f->stdout_event_source); assert(fd >= 0); - assert(fd == STDOUT_FILENO); + assert(fd == f->output_fd); if (revents & (EPOLLOUT|EPOLLHUP)) f->stdout_writable = true; @@ -377,7 +394,7 @@ static int on_sigwinch_event(sd_event_source *e, const struct signalfd_siginfo * assert(e == f->sigwinch_event_source); /* The window size changed, let's forward that. */ - if (ioctl(STDOUT_FILENO, TIOCGWINSZ, &ws) >= 0) + if (ioctl(f->output_fd, TIOCGWINSZ, &ws) >= 0) (void) ioctl(f->master, TIOCSWINSZ, &ws); return 0; @@ -400,6 +417,8 @@ int pty_forward_new( *f = (struct PTYForward) { .flags = flags, .master = -1, + .input_fd = -1, + .output_fd = -1, }; if (event) @@ -410,14 +429,42 @@ int pty_forward_new( return r; } - if (!(flags & PTY_FORWARD_READ_ONLY)) { - r = fd_nonblock(STDIN_FILENO, true); - if (r < 0) - return r; - - r = fd_nonblock(STDOUT_FILENO, true); - 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); @@ -426,7 +473,7 @@ int pty_forward_new( f->master = master; - if (ioctl(STDOUT_FILENO, TIOCGWINSZ, &ws) < 0) { + 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. */ @@ -439,7 +486,9 @@ int pty_forward_new( (void) ioctl(master, TIOCSWINSZ, &ws); if (!(flags & PTY_FORWARD_READ_ONLY)) { - if (tcgetattr(STDIN_FILENO, &f->saved_stdin_attr) >= 0) { + assert(f->input_fd >= 0); + + if (tcgetattr(f->input_fd, &f->saved_stdin_attr) >= 0) { struct termios raw_stdin_attr; f->saved_stdin = true; @@ -447,10 +496,10 @@ int pty_forward_new( 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); + tcsetattr(f->input_fd, TCSANOW, &raw_stdin_attr); } - if (tcgetattr(STDOUT_FILENO, &f->saved_stdout_attr) >= 0) { + if (tcgetattr(f->output_fd, &f->saved_stdout_attr) >= 0) { struct termios raw_stdout_attr; f->saved_stdout = true; @@ -459,10 +508,10 @@ int pty_forward_new( 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); + tcsetattr(f->output_fd, TCSANOW, &raw_stdout_attr); } - r = sd_event_add_io(f->event, &f->stdin_event_source, STDIN_FILENO, EPOLLIN|EPOLLET, on_stdin_event, f); + 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; @@ -470,7 +519,7 @@ int pty_forward_new( (void) sd_event_source_set_description(f->stdin_event_source, "ptyfwd-stdin"); } - r = sd_event_add_io(f->event, &f->stdout_event_source, STDOUT_FILENO, EPOLLOUT|EPOLLET, on_stdout_event, f); + 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; |