return loop_write(fd, cursor_position, SIZE_MAX);
}
+static int terminal_verify_same(int input_fd, int output_fd) {
+ assert(input_fd >= 0);
+ assert(output_fd >= 0);
+
+ /* Validates that the specified fds reference the same TTY */
+
+ if (input_fd != output_fd) {
+ struct stat sti;
+ if (fstat(input_fd, &sti) < 0)
+ return -errno;
+
+ if (!S_ISCHR(sti.st_mode)) /* TTYs are character devices */
+ return -ENOTTY;
+
+ struct stat sto;
+ if (fstat(output_fd, &sto) < 0)
+ return -errno;
+
+ if (!S_ISCHR(sto.st_mode))
+ return -ENOTTY;
+
+ if (sti.st_rdev != sto.st_rdev)
+ return -ENOLINK;
+ }
+
+ if (!isatty_safe(input_fd)) /* The check above was just for char device, but now let's ensure it's actually a tty */
+ return -ENOTTY;
+
+ return 0;
+}
+
+typedef enum CursorPositionState {
+ CURSOR_TEXT,
+ CURSOR_ESCAPE,
+ CURSOR_ROW,
+ CURSOR_COLUMN,
+} CursorPositionState;
+
+typedef struct CursorPositionContext {
+ CursorPositionState state;
+ unsigned row, column;
+} CursorPositionContext;
+
+static int scan_cursor_position_response(
+ CursorPositionContext *context,
+ const char *buf,
+ size_t size,
+ size_t *ret_processed) {
+
+ assert(context);
+ assert(buf);
+ assert(ret_processed);
+
+ for (size_t i = 0; i < size; i++) {
+ char c = buf[i];
+
+ switch (context->state) {
+
+ case CURSOR_TEXT:
+ context->state = c == '\x1B' ? CURSOR_ESCAPE : CURSOR_TEXT;
+ break;
+
+ case CURSOR_ESCAPE:
+ context->state = c == '[' ? CURSOR_ROW : CURSOR_TEXT;
+ break;
+
+ case CURSOR_ROW:
+ if (c == ';')
+ context->state = context->row > 0 ? CURSOR_COLUMN : CURSOR_TEXT;
+ else {
+ int d = undecchar(c);
+
+ /* We read a decimal character, let's suffix it to the number we so far read,
+ * but let's do an overflow check first. */
+ if (d < 0 || context->row > (UINT_MAX-d)/10)
+ context->state = CURSOR_TEXT;
+ else
+ context->row = context->row * 10 + d;
+ }
+ break;
+
+ case CURSOR_COLUMN:
+ if (c == 'R') {
+ if (context->column > 0) {
+ *ret_processed = i + 1;
+ return 1; /* success! */
+ }
+
+ context->state = CURSOR_TEXT;
+ } else {
+ int d = undecchar(c);
+
+ /* As above, add the decimal character to our column number */
+ if (d < 0 || context->column > (UINT_MAX-d)/10)
+ context->state = CURSOR_TEXT;
+ else
+ context->column = context->column * 10 + d;
+ }
+
+ break;
+ }
+
+ /* Reset any positions we might have picked up */
+ if (IN_SET(context->state, CURSOR_TEXT, CURSOR_ESCAPE))
+ context->row = context->column = 0;
+ }
+
+ *ret_processed = size;
+ return 0; /* all good, but not enough data yet */
+}
+
+int terminal_get_cursor_position(
+ int input_fd,
+ int output_fd,
+ unsigned *ret_row,
+ unsigned *ret_column) {
+
+ _cleanup_close_ int nonblock_input_fd = -EBADF;
+ int r;
+
+ assert(input_fd >= 0);
+ assert(output_fd >= 0);
+
+ if (terminal_is_dumb())
+ return -EOPNOTSUPP;
+
+ r = terminal_verify_same(input_fd, output_fd);
+ if (r < 0)
+ return log_debug_errno(r, "Called with distinct input/output fds: %m");
+
+ struct termios old_termios;
+ if (tcgetattr(input_fd, &old_termios) < 0)
+ return log_debug_errno(errno, "Failed to get terminal settings: %m");
+
+ struct termios new_termios = old_termios;
+ termios_disable_echo(&new_termios);
+
+ if (tcsetattr(input_fd, TCSANOW, &new_termios) < 0)
+ return log_debug_errno(errno, "Failed to set new terminal settings: %m");
+
+ /* Request cursor position (DSR/CPR) */
+ r = loop_write(output_fd, "\x1B[6n", SIZE_MAX);
+ if (r < 0)
+ goto finish;
+
+ /* Open a 2nd input fd, in non-blocking mode, so that we won't ever hang in read() should someone
+ * else process the POLLIN. */
+
+ nonblock_input_fd = r = fd_reopen(input_fd, O_RDONLY|O_CLOEXEC|O_NONBLOCK|O_NOCTTY);
+ if (r < 0)
+ goto finish;
+
+ usec_t end = usec_add(now(CLOCK_MONOTONIC), CONSOLE_REPLY_WAIT_USEC);
+ char buf[STRLEN("\x1B[1;1R")]; /* The shortest valid reply possible */
+ size_t buf_full = 0;
+ CursorPositionContext context = {};
+
+ for (bool first = true;; first = false) {
+ if (buf_full == 0) {
+ usec_t n = now(CLOCK_MONOTONIC);
+ if (n >= end) {
+ r = -EOPNOTSUPP;
+ goto finish;
+ }
+
+ r = fd_wait_for_event(nonblock_input_fd, POLLIN, usec_sub_unsigned(end, n));
+ if (r < 0)
+ goto finish;
+ if (r == 0) {
+ r = -EOPNOTSUPP;
+ goto finish;
+ }
+
+ /* On the first try, read multiple characters, i.e. the shortest valid
+ * reply. Afterwards read byte-wise, since we don't want to read too much, and
+ * unnecessarily drop too many characters from the input queue. */
+ ssize_t l = read(nonblock_input_fd, buf, first ? sizeof(buf) : 1);
+ if (l < 0) {
+ if (errno == EAGAIN)
+ continue;
+
+ r = -errno;
+ goto finish;
+ }
+
+ assert((size_t) l <= sizeof(buf));
+ buf_full = l;
+ }
+
+ size_t processed;
+ r = scan_cursor_position_response(&context, buf, buf_full, &processed);
+ if (r < 0)
+ goto finish;
+
+ assert(processed <= buf_full);
+ buf_full -= processed;
+ memmove(buf, buf + processed, buf_full);
+
+ if (r > 0) {
+ /* Superficial validity check */
+ if (context.row >= 32766 || context.column >= 32766) {
+ r = -ENODATA;
+ goto finish;
+ }
+
+ if (ret_row)
+ *ret_row = context.row;
+ if (ret_column)
+ *ret_column = context.column;
+
+ r = 0;
+ goto finish;
+ }
+ }
+
+finish:
+ RET_GATHER(r, RET_NERRNO(tcsetattr(input_fd, TCSANOW, &old_termios)));
+ return r;
+}
+
int terminal_reset_defensive(int fd, TerminalResetFlags flags) {
int r = 0;
termios->c_cc[VTIME] = 0;
}
-static int terminal_verify_same(int input_fd, int output_fd) {
- assert(input_fd >= 0);
- assert(output_fd >= 0);
-
- /* Validates that the specified fds reference the same TTY */
-
- if (input_fd != output_fd) {
- struct stat sti;
- if (fstat(input_fd, &sti) < 0)
- return -errno;
-
- if (!S_ISCHR(sti.st_mode)) /* TTYs are character devices */
- return -ENOTTY;
-
- struct stat sto;
- if (fstat(output_fd, &sto) < 0)
- return -errno;
-
- if (!S_ISCHR(sto.st_mode))
- return -ENOTTY;
-
- if (sti.st_rdev != sto.st_rdev)
- return -ENOLINK;
- }
-
- if (!isatty_safe(input_fd)) /* The check above was just for char device, but now let's ensure it's actually a tty */
- return -ENOTTY;
-
- return 0;
-}
-
typedef enum BackgroundColorState {
BACKGROUND_TEXT,
BACKGROUND_ESCAPE,
return r;
}
-typedef enum CursorPositionState {
- CURSOR_TEXT,
- CURSOR_ESCAPE,
- CURSOR_ROW,
- CURSOR_COLUMN,
-} CursorPositionState;
-
-typedef struct CursorPositionContext {
- CursorPositionState state;
- unsigned row, column;
-} CursorPositionContext;
-
-static int scan_cursor_position_response(
- CursorPositionContext *context,
- const char *buf,
- size_t size,
- size_t *ret_processed) {
-
- assert(context);
- assert(buf);
- assert(ret_processed);
-
- for (size_t i = 0; i < size; i++) {
- char c = buf[i];
-
- switch (context->state) {
-
- case CURSOR_TEXT:
- context->state = c == '\x1B' ? CURSOR_ESCAPE : CURSOR_TEXT;
- break;
-
- case CURSOR_ESCAPE:
- context->state = c == '[' ? CURSOR_ROW : CURSOR_TEXT;
- break;
-
- case CURSOR_ROW:
- if (c == ';')
- context->state = context->row > 0 ? CURSOR_COLUMN : CURSOR_TEXT;
- else {
- int d = undecchar(c);
-
- /* We read a decimal character, let's suffix it to the number we so far read,
- * but let's do an overflow check first. */
- if (d < 0 || context->row > (UINT_MAX-d)/10)
- context->state = CURSOR_TEXT;
- else
- context->row = context->row * 10 + d;
- }
- break;
-
- case CURSOR_COLUMN:
- if (c == 'R') {
- if (context->column > 0) {
- *ret_processed = i + 1;
- return 1; /* success! */
- }
-
- context->state = CURSOR_TEXT;
- } else {
- int d = undecchar(c);
-
- /* As above, add the decimal character to our column number */
- if (d < 0 || context->column > (UINT_MAX-d)/10)
- context->state = CURSOR_TEXT;
- else
- context->column = context->column * 10 + d;
- }
-
- break;
- }
-
- /* Reset any positions we might have picked up */
- if (IN_SET(context->state, CURSOR_TEXT, CURSOR_ESCAPE))
- context->row = context->column = 0;
- }
-
- *ret_processed = size;
- return 0; /* all good, but not enough data yet */
-}
-
int terminal_get_size_by_dsr(
int input_fd,
int output_fd,
projects / thirdparty / systemd.git / commitdiff
