clib: Fix Linux cursor positioning

clib/clib_term.c

@@ -21,6 +21,7 @@
 #    include <stdio.h>
 #    ifdef __GNUC__
 #        include <sys/ioctl.h>
+#        include <termios.h>
 #        include <unistd.h>
 #    endif
 #endif
@@ -90,36 +91,40 @@ term_get_size_y()
 int
 term_get_cursor_pos(uint8_t *x, uint8_t *y)
 {
-    char ch;
+    int rx, ry, n;
+    struct termios attrs;
 
-    fputs("\033[6n", stderr);
-    fflush(stderr);
-    if (getc(stdin) != 0x1b)
+    /* Capturing then uncapturing stdin like this is weird, but it'll have to do. */
+    if (tcgetattr(STDOUT_FILENO, &attrs))
         return 0;
-    if (getc(stdin) != '[')
+    int old_lflag = attrs.c_lflag;
+    attrs.c_lflag &= ~(ECHO | ICANON);
+    if (tcsetattr(STDOUT_FILENO, TCSANOW, &attrs))
         return 0;
-    *x = *y = 0;
-    while (1) {
-        ch = getc(stdin);
-        if ((ch < '0') || (ch > '9'))
-            break;
-        *x = (*x * 10) + (ch - '0');
-    }
-    while (1) {
-        ch = getc(stdin);
-        if ((ch < '0') || (ch > '9'))
-            break;
-        *y = (*y * 10) + (ch - '0');
+
+    /* Send CPR request. */
+    fputs("\033[6n", stderr);
+    fflush(stderr);
+
+    /* Read CPR response. */
+    n = scanf("\033[%d;%dR", &ry, &rx);
+    if (n >= 2) {
+        *x = rx - 1;
+        *y = ry - 1;
     }
-    *x -= 1;
-    *y -= 1;
-    return 1;
+
+    /* Uncapture stdin. */
+    attrs.c_lflag = old_lflag;
+    tcsetattr(STDOUT_FILENO, TCSANOW, &attrs);
+
+    return n >= 2;
 }
 
 int
 term_set_cursor_pos(uint8_t x, uint8_t y)
 {
-    fprintf(stderr, "\033[%d;%dH", x + 1, y + 1);
+    fprintf(stdout, "\033[%d;%dH", y + 1, x + 1);
+    fflush(stdout);
     return 1;
 }
 #else